JPH0544539U - Inkjet recording device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an inkjet recording apparatus that is highly reliable, inexpensive, and easy to maintain. [Configuration] A print head 6 for ejecting minute ink droplets,
Ink tank 1 for storing ink, and the ink tank 1
An ink supply conduit 2 connected so that ink is supplied to the print head 6 from a filter unit 11;
The damper member 4 is provided with an ink flow path whose one end communicates with the print head 6 and the other end communicates with the ink supply conduit 2 and a pressure adjusting conduit which internally seals an air layer. In the ink supply system in which the filter 5 is fixed to the branch portion between the ink flow path and the pressure adjusting conduit, the print head 6 and the damper member 4 are assembled as a head unit 11 in an easily attachable / detachable form, It is mounted on a reciprocating head carriage.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an inkjet recording device, and particularly to an ink supply system.

[0002]

[Prior Art]

 In the ink jet recording apparatus, it is important that the nozzles of the print head are not clogged due to missing dots due to air bubbles or pressure fluctuations, ink deposits, dust, foreign matter, etc. As shown in FIG. 5, one filter unit 3 is provided in a part of the ink supply conduit 2 in the ink supply system from the ink tank 1 to the printing head 6 so that the inside of the ink supply system can be improved. The ink was supplied to the nozzles in the print head and fine ink droplets were ejected to print while capturing and removing minute air bubbles, dust, foreign matter, and mitigating pressure fluctuations.

[0003]

[Problems to be solved by the device]

 However, it is not only difficult to completely capture minute air bubbles, dust, foreign matter, etc. just by providing one filter unit in a part of the ink supply line as in the conventional ink supply system. When dust or foreign matter was mixed into the ink supply system from the filter unit to the print head during the assembly of the printing device, it was not possible to prevent nozzle clogging of the print head. Therefore, in order to prevent dust and foreign matter from entering during assembly, it is necessary to work in a clean room or a clean booth until the entire ink supply system is assembled, which may result in poor work efficiency and expensive equipment. It also became a factor of cost increase.

In addition, if fine air bubbles / precipitation of the ink composition or products generated by a chemical reaction between a member forming the ink supply system and the ink are generated in the ink supply system after the filter unit, The risk of clogging of the printer could not be avoided, and the reliability of the recording device was greatly impaired. In the past, if the user had a problem with the print head due to the above-mentioned problems and maintenance was required, there is a high risk that dust, foreign matter, etc. will be mixed in when the print head is replaced locally. However, it could not be repaired and it was returned to the factory, which puts a heavy burden on the user.

Further, by providing a filter unit in a part of the ink supply conduit, it has an effect of mitigating pressure fluctuation occurring in the ink supply conduit, but mitigating pressure fluctuation affecting the inside of the nozzle of the print head. In order to achieve this, it is desirable to dispose it in the vicinity of the print head, and the conventional effect has not been sufficient.

[0006]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention is arranged near a print head, one end of which communicates with the print head, and the other end of which communicates with the ink supply conduit to supply ink to the print head. It has a function to absorb and mitigate the pressure fluctuations that accompany the reciprocating movement of the head carriage, as well as having an ink flow path to supply and a pressure adjustment conduit that seals the air layer inside. By fixing a filter to the branching portion of the damper member between the ink flow path and the pressure adjusting conduit, minute air bubbles and ink composition precipitation, and the ink forming member and ink forming By capturing the products generated by chemical reactions and ensuring the pressure relaxation effect, the reliability of the ink supply system is improved, and the assembly efficiency and cost in the manufacturing process of the printer are improved. It is intended to measure the down.

In addition, the print head and the damper member are assembled as a head unit in a form that can be easily attached and detached, and the print device is configured so as to be mounted on a reciprocating head carriage, so that filter clogging and the like can be prevented. It also simplifies the replacement of parts when a problem occurs and improves maintainability.

[0008]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. 1 is an embodiment of an ink supply system of the present invention, FIG. 2 is a plan view of a damper member 4 according to the present invention, and FIG. 3 is a sectional view of a damper member 4 according to the present invention. FIG. 4 is a sectional view of a head unit 11 embodying the present invention. In the figure, reference numeral 1 indicates an ink tank, which is not shown in the drawing, but a metal thin film or a high molecular weight element is provided so that the physical properties of the ink stored inside do not change under the influence of the external environment. A bag-shaped ink bag package made by laminating a resin film is stored. Reference numeral 2 is an ink supply line, and in consideration of air permeation and ink resistance, a multilayer tube made of a polymer resin material such as polyethylene or nylon is adopted in this embodiment, but stainless steel, aluminum, etc. The metal pipe may be used, or both may be used together. Reference numeral 3 is a filter unit, which is a structure in which a sheet-like mesh filter made by weaving nylon fiber (not shown) is sandwiched between the rubber packing and the plastic exterior from both sides, and serves as an ink reservoir and an air reservoir inside. It has a functional space.

In this embodiment, the sheet-like mesh filter has an opening of about 25 to 40 μm, but basically it must be smaller than the opening of the nozzle through which the ink is ejected. The filter unit 3 captures minute air bubbles, dust, foreign matter, deposits, etc. that are mixed or deposited in the ink supply path from the ink tank 1 to the filter unit 3, and are also stored in the ink supply pipeline. It also has the function of mitigating the sudden pressure fluctuations that occur in the openings of the filter. Reference numeral 4 is a damper member, which is composed of a member main body 4a and a damper sheet 4b, both of which are fixed by a processing method such as thermocompression bonding, ultrasonic welding or adhesion. The member main body 4a is molded from a polymer resin material such as polyethylene in consideration of ink resistance. The damper sheet 4b is a multi-layered thin film sheet made of a polymer resin such as polyethylene or nylon in consideration of air permeation and ink resistance, and seals the cross-sectional direction of the shape formed in the member body 4a. Then, in order to obtain a closed shape, it is fixed to the member main body 4a by the above-described processing method.

An ink passage 4c is formed inside the member body 4a so that ink from the ink tank 1 is supplied to the print head 6, and the print head is provided at one end of the ink passage 4c. A head connecting portion 4d connected to the nozzle 6 and a conduit connecting portion 4e connected to the ink supply conduit 2 are provided at the other end. Further, the head connecting portion 4d has a rubber packing 4f, which keeps the connection between the print head 6 and the damper member 4 and keeps the airtightness. The pipe line connecting portion 4e has a screw portion 4g for fastening the connecting joint 12, and after the ink supply pipe 2 is inserted, the damper member 4 and the ink supply pipe 2 are connected and held together with a rubber packing (not shown). Is kept.

In addition, inside the damper member 4, a pressure adjusting pipe passage portion 4h is formed in a portion different from the ink passage 4c. Since the end portion of the pressure adjusting conduit 4h is processed so that it only communicates with the ink flow path 4c at the branch portion 4i in the ink flow path 4c, but not with the other parts, the ink flow path 4c. When the ink is filled in the inside, the air inside the pressure adjusting conduit 4i is in a state of hermetically sealing the air, so that the air inside the pressure adjusting conduit 4i is compared with the ink in the solid state against the rapid pressure change acting on the ink. It has a damper effect and an effective pressure relief function. Further, the filter 5 is fixed to the branched portion 4i in the ink flow path 4c by a processing method such as thermocompression bonding, ultrasonic welding or adhesion.

In this embodiment, a nylon sheet mesh filter is used as the filter 5, and its opening has a diameter of about 20 to 25 μm. As a result, smaller air bubbles, dust, foreign matter, deposits, etc. that have passed through the filter unit 3, mixed in the ink supply path between the filter unit 3 and the filter 5, or have deposited To capture. Further, like the filter unit 3, the filter 5 also has a function of alleviating a rapid pressure fluctuation generated in the print head 6 and the ink flow path 4c at the opening hole portion of the sheet mesh filter.

Reference numeral 6 denotes a print head, and in this embodiment, as shown in FIG. 4, a plurality of ejection nozzles 6 a reciprocally move in the width direction of the recording medium 8 at intervals of 8 nozzles / mm. Are arranged in series in a direction perpendicular to the direction of movement of the recording medium, and based on the print information, the recording medium 8 such as recording paper or recording film is supplied to the recording medium 8 by a driving pulse supplied from a head driving circuit (not shown) via a flexible substrate (not shown). It uses a multi-nozzle on-demand type inkjet recording head that ejects minute ink droplets toward the nozzle. Inside the print head 6, there is an ink reservoir 6b for supplying ink to the ejection nozzle 6a, and it is designed so that ink can be quickly replenished after ejecting ink from the nozzle. The supply port 6c for receiving ink supply from the outside communicates with the ink reservoir 6b, and the head connecting portion 4d of the damper member 4 and the rubber packing 4f are detachably inserted, so that the ink supply from the outside is received. Prevents the inclusion of air bubbles and foreign substances.

Then, after fixing the print head 6 to the head fixing plate 9 with a screw or the like, the print head 6 and the damper member 4 are simply connected by inserting the head connecting portion 4d and the rubber packing 4f into the supply port 6c as described above. Can be easily assembled, and when the exterior 10 is mounted, the head unit 11 is integrally managed and flowed in a unitized state, and is mounted in the head carriage 7 in a united state. Further, since the supply port 6c, the head connecting portion 4d, and the rubber packing 4f are detachably inserted, the print head 6 and the damper member 4 can be easily disassembled, and the damper can be mounted on the head carriage 7 as it is. The member 4 can be replaced.

Next, the assembling work of the ink supply system of one embodiment of the present invention having the above configuration will be described. First, it is necessary to ensure the cleanliness of each part by assembling in a clean environment or by cleaning or sealing after manufacturing, based on the work standard in each manufacturing process. It is desirable that the filter unit 3, the damper member 4, the print head 6, the head unit 11 and the like are manufactured and assembled in a clean room or a clean booth of about class 50000 to 10000, and the ink supply pipe line 2 is manufactured. It is desirable to thoroughly wash with a solvent, but these are exactly the same in the conventional method and the present embodiment. Further, in the past, even in the factory where the assembly work of the ink supply system was carried out, a clean room or a clean booth was set up for the work. This is because there was a fear that dust and foreign matter floating in the factory environment could get into the path of the ink supply system after the filter unit 3 during the assembly work.

In this embodiment, the filter 5 is fixed in the ink flow path 4c inside the damper member 4 arranged immediately before the print head 6 after the filter unit 3, and the damper member 4 and the printing are performed. Since the head unit 11 is formed by connecting the head 6 and assembling it with the head fixing plate 9 and the outer casing 10, no equipment such as a clean room or a clean booth is required for assembling the printing device, the ink supply system, or the like. Since the filter 5 is provided in the head unit 11, only the tip of the nozzle 6a needs to be protected against dust and foreign substances during assembly, which significantly reduces the operator's attention and conversely to a clean room or clean booth. Work efficiency will be greatly improved by eliminating time loss when entering and wearing dustproof clothes.

Furthermore, if the nozzle 6a portion of the head unit 11 is sealed with a cap or the like, it is not necessary to pay much attention to dust and foreign matters, so that the sealing process of each component can be performed easily. In addition to the above, general equipment and facilities such as parts management and transportation will be sufficient. Next, the operation of the ink supply system according to the embodiment of the present invention will be described. A negative pressure generated by a suction pump of an ink suction system (not shown) is added to the tip portion of the nozzle 6a of the print head 6 so that the ink supply pipe line 2, the filter unit 3, the ink supply pipe line 2 again, and the damper. The ink in the ink tank 1 is supplied in this order to the member 4 and the print head 6, and the initial filling of the ink is executed over the entire ink supply system. In this initial ink filling operation, the confidentiality of the entire ink supply system and At the same time, clogging and line resistance are also confirmed. When ink droplets are ejected from the nozzle 6a while the ink is filled, the ink is automatically supplied by the self-pumping action generated by the capillary phenomenon and the volume change of the nozzle, and the ink is supplied from the ink tank 1 to the print head 6. A flow of ink is formed towards it.

However, since the amount of the ink droplets ejected from the nozzle is extremely small, the ink flow in the ink supply system is slow, and the recording device is also required to carry out continuous printing operation for a long time. It is a product produced by precipitation of the ink composition or chemical reaction between the ink forming member and the ink. And the like, and the dissolved gas in the ink and the air that has permeated the ink supply conduit 2 form bubble nuclei that gather together and grow into bubbles, which interferes with the normal operation of the ink supply system. It was a risk factor. Separately from this, air bubbles, foreign matter, dust, etc. that are mixed in when replacing the ink tank at the time of ink emptying or during the assembly work of the ink supply system were the same risk factors as described above.

If these risk factors are left unattended, they move to an inconvenient place due to the natural flow of ink in the ink supply system and the forced flow due to the strong suction force generated by the suction pump when the suction system operates. As a result, the line resistance increases or the ink supply line 2 is clogged, and in serious cases, it reaches the ejection nozzle 6a in the print head 6 to cause nozzle clogging. It may even cause the print head to be replaced.

A filter unit 3 and a filter 5 are arranged as a device for removing these risk factors, and the risk factors existing in the ink flow flowing from the ink tank 1 toward the print head 6 are first detected by the filter unit 3. To be captured. The risk factors captured by the filter unit 3 are mainly air bubbles, foreign substances, dust, etc. that are mixed in when replacing the ink tank at the time of ink emptying or during the assembly work of the ink supply system. The resulting products are also of a relatively large category. Risk factors are captured. There are many risk factors captured by the filter unit 3 and it may cause filter clogging in a short time. Therefore, the filter unit 3 is easy to disassemble and assemble, and the area of the filter itself is increased to prevent ink accumulation and It has a structure with an air reservoir, and is designed so that the captured risk factors do not deposit on the ink reservoir and the air reservoir and do not affect the ink supply.

If the ink pool and the air pool are designed to be large in consideration of the above, problems due to clogging of the filter unit 3 hardly occur. As described above, the effect of the filter unit 3 as a removal device is great, but minute bubbles of 25 μm or less, precipitates, products generated by chemical reaction, etc. pass through. In addition, minute air bubbles, dust, foreign matter, and deposits that have entered or deposited in the ink supply path after the filter unit 3 also flow toward the print head 6, but these dangers may occur. Factors are removed by a filter 5 provided inside the damper member 4.

The relatively large risk factors captured by the filter 5 are dust and foreign substances that are mixed in during the assembly work of the ink supply system, and thus a large amount of dust and foreign matter are clogged in a short time. However, since the area of the filter 5 is small, the supply port 6c, the head connecting portion 4d, and the rubber packing 4f are detachably inserted in consideration of maintainability, and the print head 6 and the duster are not attached. The disassembly with the damper member 4 is also easy. Even if troubles such as clogging of the filter 5 occur in the field, if the damper member 4 is replaced while paying attention to the dust prevention of the print head 6, it can be easily recovered in a short time and the burden on the user. It can be greatly reduced. Further, since the filter 5 is fixed to the branch portion 4i between the ink flow path 4c and the pressure adjusting conduit 4h, the trapped air bubbles are absorbed in the pressure adjusting conduit 4h and affect the ink supply. Absent.

As a result, only the clean ink is supplied to the print head 6, and even if there is a risk factor of passing through the filter 5, the size is 20 μm or less, and the tip of the ejection nozzle 6a. Considering that it has an elliptical shape with a diameter of 110 * 40 μm, it can be said that there is no effect. This solves the biggest problems of inkjet recording devices, such as missing prints due to minute bubbles, dust, foreign matter, and precipitates that are mixed or deposited in the ink supply path, and nozzle clogging. It is possible.

Next, the pressure relaxation action of the filter 5 will be described. Acceleration fluctuations that accompany the head carriage 7 moving back and forth and vibrations and shocks that are applied to the device cause sudden pressure fluctuations in the ink supply system. The most affected effect is the ejection of the print head 6. At the meniscus formed at the tip of the nozzle 6a, since this holding force is only the surface tension of the ink, it is destroyed even if it is not so large. If the meniscus is destroyed, the ink will flow out to the nozzle surface or the ink will recede from inside the nozzle, making it impossible to continue ejecting ink droplets. It is an important issue not to cause such a thing. As a countermeasure, the damper action is achieved by the pressure adjusting conduit portion 4i communicating with the ink passage 4c, but it is preferable that the damper is closer to the nozzle 6a for the above reason.

The filter 5 in this embodiment also has a function of removing the above-mentioned risk factors and a function of alleviating a sudden pressure fluctuation generated in the ink flow path 4c at the opening hole portion of the sheet mesh filter. In addition, the damper effect is most effectively exerted since it is arranged at the position closest to the print head 6. Further, when the ink is sucked from the tip of the nozzle 6a by the operation of the suction system, the pressure adjusting pipe line portion 4h in the damper member 4 also sucks the ink up to the branch portion 4i, so that the inside of the damper member 4 is negative pressure. After the suction system stops operating and the negative pressure at the tip of the nozzle 6a is released, the pressure adjusting conduit 4h keeps the pressure balance, so that the ink is rapidly drawn into the original state. Trying to get back. Even if the meniscus formed at the tip of the nozzle 6a is destroyed by this action, the filter 5 is connected to the print head 6 from the branched portion 4i of the ink flow passage 4c and the pressure adjusting pipe passage portion 4h. Since it is fixed in the ink flow path up to the head connecting portion 4d, the damper effect is sufficiently exerted against the pressure fluctuation as described above.

[0026]

[Effect of the device]

 As described above, according to the present invention, a filter is arranged in the vicinity of the print head, and a filter is provided at the branch portion between the ink flow path and the pressure adjustment flow path in the damper member that has the function of absorbing and reducing pressure fluctuations. By sticking, minute air bubbles / precipitation of the ink composition, capture of products generated by the chemical reaction between the ink supply system-forming member and the ink, and more reliable pressure relaxation effect, The objectives of improving the reliability of the supply system, improving the assembling efficiency in the manufacturing process of the printing apparatus, and reducing the cost are achieved, and a highly reliable and inexpensive inkjet recording apparatus can be provided.

In addition, the print head and the damper member are assembled as a head unit in a form that can be easily attached and detached, and the print device is configured to be mounted on the head carriage that reciprocates. It is possible to simplify the replacement of parts when problems occur, improve maintenance, and provide users with services such as a drastic reduction in repair time and reduction in repair costs.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of an ink supply system according to the present invention.

FIG. 2 is a plan view showing an embodiment of a damper member according to the present invention.

FIG. 3 is a sectional view showing an embodiment of a damper member according to the present invention.

FIG. 4 is a sectional view showing an embodiment of a head unit according to the present invention.

FIG. 5 is a schematic view showing a conventional ink supply system.

[Explanation of symbols]

 1 Ink Tank 2 Ink Supply Pipeline 3 Filter Unit 4 Damper Member 5 Filter 6 Print Head 7 Head Carriage 8 Recording Medium 9 Head Fixing Plate 10 Exterior 11 Head Unit 12 Connection Joint

Claims (3)

[Scope of utility model registration request] 1. A print head for ejecting at least minute ink droplets, an ink tank for storing ink, and an ink supply conduit connected so that ink is supplied from the ink tank to the print head. A damper member including a filter unit, an ink flow path whose one end communicates with the print head and the other end communicates with the ink supply conduit, a pressure adjusting conduit having an air layer sealed therein, and a filter. An inkjet recording apparatus having an ink supply system including the following. 2. A filter provided on the damper member is fixed in an ink flow passage from a branch portion between the ink flow passage and the pressure adjusting pipe passage portion to an end portion communicating with the print head. The ink jet recording apparatus according to claim 1, wherein: 3. A damper member provided with the filter is disposed closer to the print head side than the filter unit in an ink supply system of an ink jet recording apparatus, and is fixed to the damper member. The ink jet recording apparatus according to claim 1, wherein has an opening hole density equal to or less than that of the filter used in the filter unit.