JP7388026B2 - Filtration module, degassing filtration unit and inkjet image forming device - Google Patents

Description

The present invention relates to a filtration module, a degassing filtration unit, and an inkjet image forming apparatus.

In image formation using an inkjet apparatus, a filter is provided in a flow path through which ink flows, and this filter collects foreign substances in the ink.

For example, Patent Document 1 discloses a configuration including a metal mesh filter, a filter holding member, a filter case surrounding the outer periphery of the filter and the holding member, and an O-ring. In Patent Document 1, the O-ring has the role of providing airtightness between the flow path block and the filter case, as well as holding the holding member and the filter.

Japanese Patent Application Publication No. 2011-73412

However, in the technology described in Patent Document 1, the O-ring has the role of holding the filter, and the ink flows from the peripheral edge of the filter (the gap between the O-ring and the filter or the gap between the filter and the filter case). There is a risk that foreign objects may slip through.

Therefore, by providing an annular flange portion by welding or the like on the outer circumferential portion of the filter itself and pressing this flange portion with an O-ring, it is possible to prevent foreign matter from slipping through the circumferential edge of the filter. However, there is a problem in that the manufacturing cost for providing the flange portion on the filter is high.

SUMMARY OF THE INVENTION An object of the present invention is to provide a filtration module, a degassing filtration unit, and an inkjet image forming apparatus that can reduce manufacturing costs and prevent foreign matter from slipping through the peripheral edge of the filter.

The filtration module according to the present invention includes:
A filtration module that filters fluid,
a filter disposed on the first housing member side and formed from a mesh;
A seal that is arranged on the second housing member side and has a softness that elastically deforms when pressed onto the surface of the mesh so that the gap with the surface of the mesh is equal to or smaller than the size of the hole in the mesh. parts and
Equipped with
The second housing member is fixed to the first housing member by pressing the sealing member onto the surface of the mesh so that the gap is equal to or smaller than the size of the hole in the mesh.

Furthermore, the degassing filtration unit according to the present invention includes:
a degassing module that degasses fluid;
The above-mentioned filtration module, which is provided downstream of the deaeration module in the fluid flow direction and filters the fluid after deaeration;
Equipped with.

Furthermore, the inkjet image forming apparatus according to the present invention includes:
The above degassing filtration unit,
an inkjet head that is provided downstream of the degassing filtration unit in the fluid flow direction and that discharges ink as a fluid;
Equipped with.

According to the present invention, it is possible to reduce manufacturing costs and to prevent foreign matter from slipping through the peripheral edge of the filter.

1 is a diagram schematically showing an inkjet image forming apparatus according to an embodiment of the present invention. 2 is a diagram schematically showing a head unit installed in the inkjet image forming apparatus shown in FIG. 1. FIG. FIG. 2 is a diagram illustrating a filter and an O-ring according to an embodiment of the present invention. FIG. 3 is a three-sided view of a twill mesh shown as an example of a filter. FIG. 1 is a perspective view showing the appearance of a filtration module according to an embodiment of the present invention. 6 is a diagram with the first housing member removed from the filtration module shown in FIG. 5. FIG. FIG. 7 is a diagram with the support member removed from the filtration module shown in FIG. 6; 8 is a diagram showing a filter and a second housing member separated from the filtration module shown in FIG. 7. FIG. 6 is a cross-sectional view taken along line AA of the filtration module shown in FIG. 5. FIG. 10 is a cross-sectional view showing area B in FIG. 9. FIG.

Hereinafter, a filtration module, a degassing filtration unit, and an inkjet image forming apparatus according to embodiments of the present invention will be described in detail based on the drawings.

(Inkjet image forming device)
FIG. 1 is a diagram showing a schematic configuration of an inkjet image forming apparatus 1. As shown in FIG. The inkjet image forming apparatus 1 includes a paper feeding section 10, an image forming section 20, a paper discharging section 30, a main tank 40 (see FIG. 2), and a control section (not shown).

The inkjet image forming apparatus 1 transports the recording medium P stored in the paper feed section 10 to the image forming section 20 under the control of the control section, forms an image on the recording medium P in the image forming section 20, and then displays the image. The formed recording medium P is conveyed to the paper discharge section 30. As the recording medium P, in addition to paper such as plain paper or coated paper, various media capable of fixing ink that has landed on the surface, such as cloth or sheet-like resin, can be used.

The paper feed section 10 includes a paper feed tray 11 that stores the recording medium P, and a medium supply section 12 that transports and supplies the recording medium P from the paper feed tray 11 to the image forming section 20. The medium supply unit 12 includes a ring-shaped belt whose inner side is supported by two rollers, and rotates the rollers with the recording medium P placed on this belt to feed the recording medium P from the paper feed tray 11. It is transported to the image forming section 20.

The image forming section 20 includes a transport section 21, a delivery unit 22, a heating section 23, a head unit 50, a fixing section 24, a delivery section 25, and the like.

The conveying unit 21 holds the recording medium P placed on the conveying surface 212 (placing surface) of a cylindrical conveying drum 211, and the conveying drum 211 rotates in the direction of the arrow around its rotation axis (cylindrical axis). By rotating and moving around, a conveyance operation is performed to convey the recording medium P on the conveyance drum 211.

The delivery unit 22 delivers the recording medium P transported by the medium supply section 12 of the paper feed section 10 to the transport section 21 . The delivery unit 22 is provided at a position between the medium supply section 12 and the conveyance section 21 of the paper supply section 10, and picks up one end of the recording medium P conveyed from the medium supply section 12 by holding it with a swing arm section 221. , and delivered to the transport section 21 via the delivery drum 222.

The heating section 23 is provided between the arrangement position of the delivery drum 222 and the arrangement position of the head unit 50, and heats the recording medium P transported by the transport section 21 so that the temperature falls within a predetermined temperature range. Heat P. The heating unit 23 includes, for example, an infrared heater, and generates heat by supplying electricity to the infrared heater based on a control signal supplied from the control unit.

The head unit 50 injects nozzles provided on an ink ejection surface (head chip 95 described below) facing the transport surface 212 of the transport drum 211 at an appropriate timing according to the rotation of the transport drum 211 holding the recording medium P. An image is formed on the recording medium P by ejecting ink from the recording medium P. The head unit 50 is arranged such that the ink ejection surface and the conveyance surface 212 are separated by a predetermined distance. In the image forming section 20, four head units 50 respectively corresponding to the four color inks of yellow (Y), magenta (M), cyan (C), and black (K) are installed in the Y direction from the upstream side in the conveyance direction of the recording medium P. , M, C, and K are arranged at predetermined intervals in this order. The configuration of the head unit 50 will be described later with reference to FIG. 2.

The fixing section 24 has a light emitting section disposed across the width of the conveyance section 21 (width in the rotational axis direction of the conveyance drum 211), and the light emitting section emits light onto the recording medium P placed on the conveyance section 21. The ink ejected onto the recording medium P is cured and fixed by irradiating energy rays such as ultraviolet rays. The light emitting section of the fixing section 24 is arranged facing the transport surface 212 between the position of the head unit 50 and the position of the transfer drum 251 of the delivery section 25 in the transport direction.

The delivery section 25 includes a belt loop 252 having a ring-shaped belt whose inner side is supported by two rollers, and a cylindrical transfer drum 251 that transfers the recording medium P from the conveyance section 21 to the belt loop 252. The recording medium P transferred from the conveyance section 21 onto the belt loop 252 by the transfer drum 251 is conveyed by the belt loop 252 and sent to the paper discharge section 30 .

The paper discharge section 30 has a plate-shaped paper discharge tray 31 on which the recording medium P sent out from the image forming section 20 by the delivery section 25 is placed.

(head unit)
FIG. 2 is a diagram schematically showing a head unit 50 mounted on the inkjet image forming apparatus 1. In FIG. 2, a head unit 50 for one color of ink and a corresponding main tank 40 are shown. The main tank 40 and head unit 50 have the same configuration for other colors.

The main tank 40 stores ink (fluid) used for printing. Ink stored in the main tank 40 is supplied to the sub-tank module 60 using a supply pump 41.

The head unit 50 includes a sub-tank module 60, a degassing module 70, a filtration module 80, an inkjet head 90, and the like. A deaeration filtration unit consisting of a deaeration module 70 and a filtration module 80 is arranged at one end of the subtank module 60, and the filtration module 80 is arranged between the subtank module 60 and the deaeration module 70. . In this way, since the deaeration module 70 and the filtration module 80 are arranged at one end of the sub-tank module 60, they can be easily removed when replacing the deaeration module 70 and the filtration module 80. ing.

Note that depending on the type of ink, such as heat-melting ink such as UV ink, the ink may be heated. It is desirable that the configuration is connected to the For example, it is desirable that these casings be made of aluminum, which has good thermal conductivity.

The sub-tank module 60 includes a first sub-tank 61, a liquid feeding pump 62, a second sub-tank 63, a liquid level sensor 64, a pressure sensor 65, and the like. Ink supplied from the main tank 40 using the supply pump 41 is stored in the first sub-tank 61. The first sub-tank 61 also stores ink returned from the inkjet head 90, as will be described later.

The ink stored in the first sub-tank 61 is sent to the degassing module 70 and the filtration module 80 by suction using the liquid sending pump 62 .

Gas (air) is removed from the ink supplied to the degassing module 70. The deaeration module 70 includes a hollow fiber body 71 configured by winding a hollow fiber fabric made of a large number of hollow fibers, a channel pipe 72 that supplies ink to the hollow fiber body 71, and a channel pipe 72 that supplies ink to the hollow fiber body 71 and the channel pipe. It has a housing 73 (casing) that accommodates 72. The inside of the hollow fiber of the hollow fiber body 71 is kept in a vacuum state by a vacuum pump (not shown), and the ink is degassed by sucking gas from the ink in contact with the outer surface of the hollow fiber into the inside of the hollow fiber. Is going. Note that this degassing module 70 is just one example, and any configuration can be applied as long as it can degas ink. Further, when heating the ink, a heating mechanism for heating may be provided in the degassing module 70 having a large heat capacity.

The ink supplied to the filtration module 80 is filtered by the filtration module 80. This filtration module 80 is arranged so that a filter 84, which will be described later, is parallel or substantially parallel to the axial direction of the flow path pipe 72 of the degassing module 70. With this arrangement, the degassing module 70 and the filtration module 80 can be arranged in a compact manner at one end of the sub-tank module 60. The detailed configuration of the filtration module 80 will be described later with reference to FIGS. 3 to 10.

The ink that has been degassed by the deaeration module 70 and filtered by the filtration module 80 is supplied to the second sub-tank 63 using the liquid feed pump 62 . The second sub-tank 63 has a configuration in which the air pressure within the second sub-tank 63 can be adjusted by a back pressure pump (not shown), and by adjusting this air pressure, the ejection of ink from the nozzles of the inkjet head 90, which will be described later, is controlled. are doing.

A liquid level sensor 64 is provided inside the second sub-tank 63 and detects the height of the liquid level of the ink supplied to the second sub-tank 63. When foreign matter is collected in the filtration module 80 and the pressure loss in the filtration module 80 increases, the filtration module 80 needs to be replaced. The liquid level sensor 64 monitors the rate of change in the liquid level per unit time, and when this rate of change becomes smaller than a predetermined value, an alarm is sent to the inkjet image forming apparatus to request replacement of the filtration module 80. I am trying to display it as 1.

Further, a pressure sensor 65 is provided on the outlet side of the second sub-tank 63 to detect the ejection pressure of the ink supplied from the second sub-tank 63. This pressure sensor 65 is used to adjust the air pressure within the second sub-tank 63.

The inkjet head 90 includes an inlet 91, an upper head flow path 92, a filter 93, a lower head flow path 94, a head chip 95, an outlet 96, a drive circuit (not shown), and the like. Although FIG. 2 illustrates a configuration in which two inkjet heads 90 are connected in series, the number of inkjet heads 90 may be one, or three or more inkjet heads 90 may be connected in series.

The inlet 91 is connected to the head upper flow path 92, and the ink from the second sub-tank 63 flows into the head upper flow path 92 via the inlet 91 (in FIG. 2, the inlet 91 of the upstream inkjet head 90). Supplied. A filter 93 is arranged between the upper head flow path 92 and the lower head flow path 94, and the ink supplied to the upper head flow path 92 is filtered by the filter 93 and then supplied to the lower head flow path 94. be done.

The head chip 95 is provided with elements for controlling opening and closing of a plurality of nozzles and individual nozzles, and these elements are controlled by a drive circuit. The ink supplied to the lower head flow path 94 is ejected from the nozzle that is controlled to be open to form an image.

The outlet 96 is also connected to the head upper flow path 92, and unused (ejected) ink is passed through the outlet 96 (in FIG. 2, the outlet 96 of the downstream inkjet head 90) to the head upper flow path 92. and is returned to the first sub tank 61. Note that an outlet may be separately connected to the lower head flow path 94 to return unused (discharged) ink from the lower head flow path 94 to the first sub-tank 61. In this way, the ink in the head unit 50 is circulated, and while it is being circulated, foreign substances in the ink are filtered out by the filtration module 80.

(filtration module)
In the above-described head unit 50, there is a possibility that a portion of the ink degassed by the deaeration module 70 may aggregate to form an aggregate. Therefore, a filtration module 80 is provided on the downstream side of the degassing module 70, and the filtration module 80 collects foreign substances in the ink, including aggregates that have become foreign substances, and filters the ink.

However, when applying the technology described in Patent Document 1 as a filtration module, the O-ring described in Patent Document 1 serves to hold the filter. Therefore, there is a risk that foreign matter in the ink may slip through the peripheral edge of the filter (the gap between the O-ring and the filter or the gap between the filter and the filter case).

In addition, if an annular flange is provided on the outer circumference of the filter by welding or the like and this flange is pressed with an O-ring, it is possible to prevent foreign matter from slipping through the peripheral edge of the filter. There is a problem in that the manufacturing cost for providing this is high.

Therefore, in this embodiment, the filtration module 80 has the configuration shown in FIG. 3. Specifically, the filtration module 80 is pressed onto the mesh surface such that the gap G between the filter 84 formed from the mesh, the O-ring 837, and the mesh surface is less than or equal to the size of the hole in the mesh. It also includes an O-ring 837 as a sealing member. Examples of the size of the holes in the mesh include the hole diameter of the mesh and the filtration particle size of the mesh.

The filter 84 may be of any type as long as it is made of mesh. The entire surface may be formed of mesh. Further, depending on the target filtration particle size, a twill weave, a flat tatami weave mesh, etc. may be used. Regardless of which mesh is used, it is sufficient that when the O-ring 837 is pressed onto the mesh surface, the gap G between the O-ring 837 and the mesh surface is equal to or smaller than the size of the hole in the mesh. The sealing member may be an O-ring or something similar to an O-ring, but a soft material that elastically deforms to follow the roughness (irregularities) of the mesh surface is desirable.

As an example of the filter 84, FIGS. 3 and 4 illustrate a filter 84 formed from a twill mesh. The filter 84 shown in FIGS. 3 and 4 is formed by twilling warp threads 841 and weft threads 842 of thin metal wires made of, for example, SUS (stainless steel).

The present inventor prototyped a filtration module 80 having the configuration described below using a filter 84 made of a twilled mesh with a mesh hole size of 10 μm. As a result of measurement, the surface roughness (maximum height roughness Rz) of the mesh surface of the filter 84 before trial production was 15 μm. As a result of evaluating the prototype filtration module 80 by bubble point pressure measurement, it was confirmed that the maximum pore diameter of the bubbles obtained by bubble point pressure measurement was 10 μm or less. In other words, it was confirmed that the mesh hole size of the filter 84 including the gap G in FIG. 3 was 10 μm or less. This means that foreign particles larger than 10 μm can be prevented from slipping through from around the O-ring 837, which is the peripheral edge of the filter 84.

In this way, by making the gap G between the O-ring 837 and the mesh surface of the filter 84 smaller than the size of the hole in the mesh, it is possible to prevent foreign matter from slipping through from the peripheral edge of the filter 84. . Furthermore, since there is no need to provide a flange on the filter 84, manufacturing costs can also be reduced.

In addition, since the filter 84 and O-ring 837 having the configuration described in FIG. 3 can be applied to any shape of filter, the degree of freedom in designing the shape of the filter 84 increases. In other words, regardless of the shape of the filter, manufacturing costs can be reduced and foreign matter can be prevented from slipping through the peripheral edge of the filter.

Next, the configuration of the filtration module 80 including the above-described filter 84 and O-ring 837 will be described in more detail with reference to FIGS. 5 to 10.

The filtration module 80 includes a first housing member 81, a support member 82, and a second housing member 83. The support member 82 is sandwiched between the first housing member 81 and the second housing member 83. Each member is fixed to each other using a plurality of screws and screw holes, but their description is omitted in FIGS. 5 to 10.

A discharge port 811 through which ink is discharged is provided on the outer surface of the first housing member 81 that contacts the sub-tank module 60 (see FIG. 2). The discharge port 811 is connected to the liquid feeding pump 62 of the sub-tank module 60. An O-ring groove 812 is provided around the discharge port 811, and an O-ring 813 is arranged in the O-ring groove 812, thereby forming a connection between the sub-tank module 60 and the first housing member 81 (flow path to the liquid pump 62). is sealed. Further, a recess 814 (see FIG. 9) having a shape corresponding to the shape of the filter 84 shown in FIG.

A plurality of openings 821 passing through the support member 82 are formed in the support member 82 . These openings 821 are arranged within a range of the filter 84 shown in FIG. 8, and allow the ink that has passed through the filter 84 to pass into the recess 814 of the first housing member 81. A support portion 822 is formed between the openings 821, and the plurality of support portions 822 support the filter 84 from the downstream side of the ink flowing through the filtration module 80, thereby preventing the filter 84 from deflecting. . Further, an O-ring groove 823 is provided around these openings 821, and an O-ring 824 is disposed in the O-ring groove 823 to seal between the first housing member 81 and the support member 82. .

The opening 821 formed in the support member 82 may have any shape, but if you want to increase the opening ratio (reduce pressure loss) while preventing the filter 84 from deflecting, as shown in FIG. A long hole shape is desirable. In the case of an elongated hole shape, the manufacturing cost for processing is low and the strength of the support portion 822 that becomes the rib can be ensured.

On the inner surface of the second housing member 83, an O-ring groove 831 is provided on the outer circumferential side of the O-ring 837 pressed by the filter 84, and an O-ring 832 is disposed in the O-ring groove 831. 82 and the second housing member 83 are sealed.

A supply port 833 through which ink is supplied is provided on the outer surface of the second housing member 83 that contacts the degassing module 70 (see FIG. 2). Although not shown, an O-ring groove is provided around the supply port 833, and the O-ring is arranged in this O-ring groove between the second housing member 83 and the degassing module 70 (degassing). The flow path from the module 70 to the filtration module 80) is sealed.

A recess 834 having a shape corresponding to the shape of the filter 84 is also provided on the inner surface of the second housing member 83 and communicates with the supply port 833 . A guide groove 835 is formed in the recess 834 so that the ink supplied from the supply port 833 spreads over the entire area of the recess 834 .

An O-ring groove 836 is provided at the peripheral edge of the recess 834, and an O-ring 837 is disposed in the O-ring groove 836. O-ring 837 will be placed upstream of filter 84. As explained in FIG. 3, this O-ring 837 is pressed onto the mesh surface so that the gap G between the mesh surface of the filter 84 and the O-ring 837 is less than or equal to the size of the hole in the mesh. . Thereby, it is possible to prevent foreign matter from slipping through from the peripheral edge of the filter 84. Note that the ink itself leaks from the peripheral edge of the filter 84, but since the outside of the filter 84 is sealed with the above-mentioned O-ring 832, no ink leaks to the outside of the filtration module 80.

Furthermore, a convex portion 838 is formed in an annular shape along the O-ring groove 836 on the inside of the O-ring groove 836, and a convex portion 839 is formed in an annular shape along the O-ring groove 836 on the outside thereof. There is. In these convex portions 838 and 839, as shown in FIG. It's getting bigger.

Even if the filter 84 outside the O-ring 837 is damaged, the filtration performance of the filtration module 80 will not be affected. On the other hand, if the filter 84 inside the O-ring 837 comes into contact with, for example, the protrusion 838 and damages this part, the filtration performance may deteriorate (foreign objects of a size that should be blocked may slip through). . Therefore, as described above, the gap H1 is made larger than the gap H2 to prevent the filter 84 from being damaged by the convex portion 838. This gap H1 may be made larger as long as the O-ring 837 can be held within the O-ring groove 836.

Further, the surface roughness of the support member 82 is made smaller than that of the mesh surface of the filter 84. This means that if the surface roughness of the support member 82 is greater than the surface roughness of the mesh surface of the filter 84, the surface roughness of the mesh surface of the filter 84 that is in contact with the support member 82 will imitate the surface roughness of the support member 82. This is because there is a possibility that it will become larger. In that case, the gap G between the mesh surface of the filter 84 and the O-ring 837 may be particularly affected. Therefore, the surface roughness of the support member 82 is made smaller than the surface roughness of the mesh surface of the filter 84 so as not to affect the gap G. As for the surface roughness of the support member 82, it is desirable that its maximum height roughness Rz is, for example, 6.3 μm or less.

The flow of ink in the filtration module 80 having the above-described configuration will be briefly described. Ink from the degassing module 70 is supplied from the supply port 833, flows through the guide groove 835, and is supplied to the entire area of the recess 834. The ink supplied to the recess 834 is filtered by the filter 84 and is supplied to the recess 814 via the opening 821. The ink supplied to the recess 814 is discharged from the discharge port 811 and supplied to the second sub-tank 63. At this time, since the filtration module 80 includes the filter 84 and the O-ring 837 having the configuration described in FIG. There is no way to pass it through.

In the above embodiment, an example was explained in which the filter 84 and O-ring 837 having the configuration described in FIG. 3 are applied to the filtration module 80 of the head unit 50. It can also be applied to parts. Furthermore, the present invention can be applied not only to the inkjet image forming apparatus 1 but also to other apparatuses that require filtration.

Further, the above embodiments are merely examples of implementation of the present invention, and the technical scope of the present invention should not be construed as limited by these embodiments. That is, the present invention can be implemented in various forms without departing from its gist or main features.

1 Inkjet image forming apparatus 70 Degassing module 80 Filtration module 81 First housing member 82 Support member 821 Opening 83 Second housing member 838, 839 Convex portion 84 Filter 837 O-ring

Claims (11)

A filtration module that filters fluid,
a filter disposed on the first housing member side and formed from a mesh;
It is arranged on the second housing member side and has the flexibility to elastically deform when pressed onto the surface of the mesh so that the gap with the surface of the mesh is equal to or less than the size of the hole in the mesh. a seal member;
Equipped with
The second housing member is fixed to the first housing member by pressing the sealing member onto the surface of the mesh so that the gap is equal to or less than the size of the hole in the mesh.
filtration module. A support member that supports the filter from the downstream side in the fluid flow direction is provided between the first housing member and the second housing member ,
The filtration module according to claim 1. The surface roughness of the support member is smaller than the surface roughness of the mesh.
The filtration module according to claim 2. A plurality of openings are formed in the support member.
The filtration module according to claim 2 or 3. the opening is a long hole;
The filtration module according to claim 4. The second housing member has a groove in which the seal member is arranged,
The gap between the surface of the second housing member inside the groove and the surface of the mesh is larger than the gap between the surface of the second housing member outside the groove and the surface of the mesh.
A filtration module according to any one of claims 1 to 5. The filtration module according to any one of claims 1 to 6, wherein the filter is formed from a twill mesh. a degassing module that degasses the fluid;
The filtration module according to any one of claims 1 to 7, which is provided downstream of the deaeration module in the flow direction of the fluid and filters the fluid after deaeration;
A degassing filtration unit equipped with. The casing of the filtration module and the casing of the degassing module are thermally connected to each other.
The degassing filtration unit according to claim 8. At least one of the casings is made of aluminum.
The degassing filtration unit according to claim 9. The degassing filtration unit according to any one of claims 8 to 10,
an inkjet head that is provided downstream of the degassing filtration unit in the flow direction of the fluid and that discharges ink as the fluid;
An inkjet image forming apparatus.

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