JP2012101415A - Recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording apparatus that prevents thickening of ink and can carry out high-definition recording over long time.SOLUTION: The recording apparatus includes: a recording head having a flow path forming part 14 which has an ejection orifice plate 18 having ejection orifices 9 and respective liquid chambers 8 provided in the orifices 9 to supply ink to the orifices 9, and an energy generating element 7; and ink tanks 6 and 6'. A surface layer 14' of the flow path forming part 14 opposes to the outside of the ejection orifice plate 18, and an opening 31 is provided opposing to the orifices 9 in the surface layer 14' of the flow path forming part 14. Further an ink reservoir 10 is provided between the ejection orifice plate 18 and the opening 31 of the surface layer 14', and a circulation flow path 11 communicating with the ink reservoir 10 is provided. Both ends of the circulation flow path 11 are respectively connected to an inlet 32 and an outlet 33 connected to the circulation flow path 11. The inlet 32 and the outlet 33 and the respective liquid chambers 8 are connected to the ink tanks 6 and 6'.

Description

  The present invention relates to a recording apparatus that performs recording by discharging ink.

  As a representative example of an ink jet recording method (drop-on-demand method) in which ink is ejected intermittently from a discharge port provided in a recording head in accordance with recording information and adhered to a recording medium such as paper, a thermal method and a piezoelectric method are used. There is an element system. The thermal method is a method in which ink is foamed by thermal energy and ink droplets are ejected from the ejection port by the foaming pressure. On the other hand, the piezoelectric element method is a method in which ink droplets are ejected from the ejection port by changing the pressure in the liquid chamber provided in each ejection port by deformation of the piezoelectric element. In a recording apparatus using such a type of recording head, moisture or the like in the ink in the vicinity of the ejection port may evaporate, and the ink in the vicinity of the ejection port may increase in viscosity due to the accompanying advection. As a result, ink may not be ejected from all or some of the ejection ports, or a state where the ink ejection amount does not reach a desired value may occur. In addition, when a large amount of mist-like ink mist that has been ejected from the ejection port but does not reach the recording medium adheres to the vicinity of the ejection port, the adhered ink mist hinders ink ejection and causes ink droplet landing deviation.

  When applying a recording apparatus using an inkjet recording head to commercial recording that requires high-speed recording, a full multi-type recording head in which discharge ports are aligned corresponding to the entire width of the recording medium is often used. It is done. In a recording apparatus called a line printer having such a recording head, recording is performed without the recording head reciprocating in a direction perpendicular to the recording medium conveyance direction. In a recording apparatus for commercial recording, continuous recording for a long time is desirable in order to finish recording on a large number of recording media in a short time. However, if the suction recovery operation of the recording head is performed during recording in order to prevent ink thickening, continuous recording for a long time will be hindered. Further, since the full multi-type recording head has a large number of ejection openings arranged corresponding to the entire width of the recording medium, the running cost is greatly increased if preliminary ejection is performed. Measures for solving these problems and configuring an ink jet recording head capable of continuous recording for a long time are required.

  As a countermeasure against the ink thickening phenomenon and the ink mist adhering to the vicinity of the ejection opening in the line printer, the countermeasure disclosed in Patent Document 1 is known. In Patent Document 1, a thermal-type ink jet recording head has a configuration in which an opening wider than the cross-sectional area of the ejection port is formed on the outer surface of the recording head corresponding to the ejection port, and the ink meniscus is held by this opening portion. is doing. Moreover, adjacent openings communicate with each other via a communication part. According to such a configuration, even if floating ink mist adheres to the opening, it is absorbed by the ink in the opening, so that the ink mist does not adversely affect ink ejection. In addition, after ink ejection, the ink in the opening corresponding to the ejection port where ink is not ejected moves to the opening corresponding to the ejection port where ink is ejected via the communicating portion. As a result, fresh ink that is not thickened from the liquid chamber is also replenished to the opening where ink is not ejected.

JP 2006-95857 A

  However, even in the method disclosed in Patent Document 1, in a non-recording state where ink is not ejected over a long period of time, it is not possible to completely avoid ejection failure due to evaporation of moisture or the like from the ink. When ink ejection is started after a long non-recording state, the ink droplets immediately after the start are thickened, resulting in a decrease in recording quality and landing deviation. In addition, depending on the recording information, ink is ejected only from specific ejection ports, and ejection characteristics such as ejection speed, ejection ink droplet amount, and ink refilling speed vary with the ejection ports with low ejection frequency. There is a possibility. This variation may adversely affect the recording quality on the recording medium.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a recording apparatus that solves the above-described problems, suppresses ink thickening, and enables high-quality recording over a long period of time.

  The recording apparatus of the present invention includes a recording head and an ink tank. The recording head is provided with a flow path forming unit having a discharge port plate having a plurality of discharge ports for discharging ink and an individual liquid chamber provided for each discharge port for supplying ink to the discharge port. It has been. In addition, an energy generating element that generates energy for discharging the ink stored in the individual liquid chamber is also provided.

  The surface layer of the flow path forming part faces the outside of the discharge port plate. Openings are respectively provided at positions on the surface layer of the flow path forming portion facing the discharge ports. An ink reservoir is provided between the discharge port plate and the opening of the surface layer, and a circulation channel communicating with the ink reservoir is provided. The opening area of the opening is larger than the opening area of the discharge port. Both end portions of the circulation channel are connected to an inflow portion and an outflow portion where the circulation channels are connected to each other, and the inflow portion, the outflow portion, and the individual liquid chamber are connected to the ink tank.

  Since fresh ink that does not always thicken is supplied to the vicinity of the ejection port, there is no effect of thickening even on ejection ports that are not ejected over a long period of time. High-quality recording is possible.

1 is a schematic configuration diagram of an embodiment of a recording apparatus according to the present invention. FIG. 2 is an enlarged cross-sectional view of the recording head according to the first embodiment of the present invention. It is the schematic which expanded the discharge outlet vicinity. It is a schematic block diagram of the recording head of the 2nd Embodiment of this invention. It is the schematic which shows the flow of the ink in the 3rd Embodiment of this invention. It is a schematic diagram of the recording head of the 4th Embodiment of this invention. It is a schematic diagram of the recording head of the 5th Embodiment of this invention. It is a schematic diagram of the recording head of the 6th Embodiment of this invention. It is an expanded sectional view of the recording head of the 7th Embodiment of this invention. FIG. 10 is a plan view of the recording head of FIG. 9. FIG. 10 is an enlarged schematic view of the vicinity of the ejection opening of the recording head of FIG. 9. It is a modification of the recording head of 7th Embodiment. It is another modification of the recording head of 7th Embodiment. It is an expanded sectional view of the recording head of the 8th Embodiment of this invention. FIG. 15 is a plan view of the recording head in FIG. 14. FIG. 15 is an enlarged schematic view of the vicinity of the ejection opening of the recording head of FIG. 14.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, the same number is attached | subjected to the structure which has the same function in an accompanying drawing, and the description may be abbreviate | omitted. Note that the present invention is not limited thereby.

  FIG. 1 is a schematic configuration diagram of an embodiment of a recording apparatus according to the present invention. In this recording apparatus, the recording medium 2 is placed on an endless belt-like conveyance belt 4 stretched around a conveyance roller 3 as conveyance means, and the recording medium 2 is driven by the conveyance belt 4 by driving the conveyance belt 4. Be transported.

  In the example of the recording apparatus shown in FIG. 1, an ink jet recording head 1 having a recording element substrate in which ejection openings are aligned over a range corresponding to the width of the recording medium 2 is used. In this embodiment, four recording heads 1 are provided corresponding to four colors, for example, yellow (Y), magenta (M), cyan (C), and black (Bk). They are arranged in order in the transport direction of the recording medium 2. By discharging the recording ink from the recording head 1 while conveying the recording medium 2 by the conveying belt 4, full-color recording is performed on the recording medium 2 at high speed.

[First Embodiment]
FIG. 2 is an enlarged cross-sectional view of the recording head according to the first embodiment of the present invention. 3 is an enlarged schematic view of the vicinity of the discharge port 9, FIG. 3A is a schematic view of the upper surface of the vicinity of the discharge port 9, and FIG. 3B is AA ′ in FIG. It is the schematic of a cross section.

  The recording head is composed of a substrate (not shown) provided with a circuit, a piezoelectric element 7 (to be described later), and a flow path forming portion 14 in which a discharge port 9 and a flow path for ink are formed.

  Inside the flow path forming unit 14, a discharge port plate 18 provided with a plurality of discharge ports 9 penetrating therethrough, and an individual plate formed for each discharge port 9 and partially formed using the discharge port plate 18. A liquid chamber 8 and a common liquid chamber 12 connected to each individual liquid chamber 8 via a throttle portion 13 are provided. The common liquid chamber 12 is connected to the ink tank 6 and the ink tank 6 ′ in which ink is stored via the ink flow path 22.

  Further, the surface layer 14 ′ constituting the surface of the flow path forming portion 14 faces the outside of the discharge port plate 18. Openings 31 are provided in the surface layer 14 ′ at positions corresponding to the respective discharge ports 9. Further, between the surface layer 14 ′ and the discharge port plate 18, a circulation channel 11 through which ink that circulates corresponding to each discharge port 9 flows is provided. The discharge port 9 and the surface of the circulation channel 11 are provided. An ink reservoir 10 is provided at the position of the opening 31 of the layer 14 ′. The opening 31 of the surface layer 14 ′ is larger than the opening area of the discharge port 9. Further, the position corresponding to the circulation channel 11 of the surface layer 14 ′ is narrowly opened along the circulation ink channel 11. That is, as shown in FIGS. 3A and 3B, the ink reservoir 10 and the circulation channel 11 are exposed to the outside from the surface layer 14 ′ of the channel forming unit 14.

  The circulation channel 11 is provided at each ejection port 9, and both ends thereof are connected to the common ink inflow portion 32 and the common ink outflow portion 33. The common ink inflow portion 32 and the common ink outflow portion 33 are each connected to the ink tank 6 via the ink flow path 22. A pump 5 is provided as an ink flow means for circulating ink in each of the ink flow paths 22 connected from the ink tank 6 to the common ink inflow portion 32 and the common ink outflow portion 33. If the ink circulation is performed smoothly, the pump 5 may be one instead of both between the ink tank 6 and the common ink inflow portion 32 and between the ink tank 6 and the common ink outflow portion 33. Absent.

  An energy generating element for causing the ink to protrude from the ejection port 9 at a position corresponding to the individual liquid chamber 8 on the surface (back surface layer 14 ″) opposite to the surface layer 14 ′ of the flow path forming portion 14. A piezoelectric element 7 is provided.

  As described above, the ink tank 6 passes through the ink flow path 22, the common ink inflow portion 32, the circulation flow path 11 through the ink reservoir 10, the common ink outflow portion 33, and the ink flow path 22 from the ink tank 6. A circulation path is circulated to circulate ink. An ink flow path from the ink tank 6 ′ to the ejection port 9 through the ink flow path 22, the common liquid chamber 12, the throttle portion 13, and the individual liquid chamber 8 is also completed.

  When the ink tanks 6 and 6 ′ are attached to the recording apparatus, the ink in the ink tank 6 ′ is filled into the individual liquid chamber 8 by capillary force or the like. Further, the ink flows into the circulation channel 11 through the discharge port 9 by the capillary force. At the same time, the ink for circulation is also supplied from the ink tank 6, and the circulation path through which the ink circulates fills the ink. Then, the ink from the ink tank 6 always flows as shown by the arrows in FIGS. 2 and 3 by the pump 5 which is the ink flow means.

  When the ink from the ink tank 6 passes through the ink reservoir 10 and the circulation flow path 11, it evaporates from a portion exposed to the outside of the surface layer 14 ′, resulting in ink thickening. Therefore, the ink is always supplied from the ink tank 6 to the ink reservoir 10 and the circulation channel 11 by the pump 5 so as to eliminate the influence of the ink thickening. Desirably, the amount of ink supplied to the ink reservoir 10 and the ink flow path 11 is made larger than the amount of ink to be evaporated.

  The recording head of the present invention is used by being mounted on a recording apparatus having a recording medium transport mechanism, an ink supply mechanism to the recording head, a control mechanism of the recording apparatus, and the like. The piezoelectric element 7 corresponding to the required pixel is selectively driven in accordance with the recording image data taken into the recording apparatus, and ink droplets are ejected from the discharge port 9 of the individual liquid chamber 8 corresponding to the driven piezoelectric element 7. Is discharged toward the recording medium, whereby recording on the recording medium is performed.

  In discharging the ink, when the piezoelectric element 7 is driven, the pressure in the individual liquid chamber 8 changes with the deformation of the piezoelectric element 7, and the ink in the individual liquid chamber 8 is pushed out through the discharge port 9. It is discharged toward the recording medium through the reservoir 10. At this time, a droplet corresponding to the cross-sectional area of the discharge port 9 is discharged.

  Immediately after ink ejection, the ink is partially removed from the ink reservoir 10. However, the ink remaining in the ink reservoir 10, the ink sent to the circulation flow path 11, or the ink supplied from the individual liquid chamber 8 through the discharge port 9 by capillary force is used again to the ink reservoir 10. Is filled.

  As described above, according to the present embodiment, the ink reservoir 10 that covers the ejection port 9 and the ink in the circulation flow path 11 are constantly flowing by the pump 5 that is a flow means. Accordingly, since ink having sufficient moisture is always supplied to the ejection port 9 and the vicinity thereof, it is possible to prevent the ink from being thickened by evaporation. Even when a non-ejection state in which ink is not ejected continues for a long time, the ink in the ink reservoir 10 and the circulation channel 11 is circulated, so that the ejection port 9 is not clogged, and the viscosity of the ink is increased. Therefore, ink can be stably discharged from the discharge port 9. Also, variations in ink ejection characteristics such as ejection speed, ejected ink amount, or ink refillability can be kept small between the ejection ports 9 having different ink ejection frequencies. Therefore, according to this embodiment, high-quality recording can be performed continuously for a long time.

[Second Embodiment]
FIG. 4 is a schematic configuration diagram of a recording head according to the second embodiment of the present invention. FIG. 4A is an enlarged schematic view of the upper surface in the vicinity of the ejection port 9, and FIG. ) Is a schematic view of a BB ′ cross section. In the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the present embodiment, the circulation channel 11 is not exposed to the outside from the surface layer 14 ′ of the channel forming unit 14 of the first embodiment. However, an opening 31 facing the discharge port 9 is provided in the surface layer 14 '. An opening corresponding to the circulation channel 11 may not be formed in the surface layer 14 ′, or the opening corresponding to the circulation channel 11 may be covered with a shielding member (not shown).

According to the present embodiment, by preventing the circulation channel 11 from being exposed to the outside from the surface layer 14 ′ of the channel formation member 14, excessive ink evaporation from the circulation channel 11 can be suppressed. . Further, unlike the first embodiment, since the entire periphery of the opening 31 is surrounded by the surface layer 14 ′ (or the surface layer 14 ′ and the shielding member), the capillary force for holding the ink in the opening 31 is increased. Get higher. As a result, even if the ink is circulated at a faster flow rate by the ink flow means, the possibility that the ink in the ink reservoir 10 overflows from the opening 31 or the ink does not accumulate in the ink reservoir 10 is reduced. it can.
[Third Embodiment]
The description of the same configuration as that of the above embodiment is omitted. In the present embodiment, in the recording head of the first embodiment shown in FIG. 2, a pump is also provided as an ink flow means in the ink flow path 22 that connects the ink tank 6 ′ and the common liquid chamber 12. By doing so, as shown in FIG. 5, even in the non-ejection state, ink flows from the individual liquid chamber 8 to the circulation channel 11 through the ejection port 9 and the ink reservoir 10. For this reason, the ink inside the ejection port 9 can be made to flow without locally stagnation. As a result, it is possible to effectively suppress the density distribution due to the stagnation of the ink at the ejection port 9. In addition, it is possible to more effectively reduce the influence of ink thickening due to evaporation from the portions of the ink reservoir 10 and the circulation channel 11 exposed to the outside.

  Note that the configuration of the present embodiment may be combined with the configuration of the second embodiment.

[Fourth Embodiment]
6A and 6B are schematic views of a recording head according to a fourth embodiment of the present invention. FIG. 6A is a plan view of the recording head, and FIG. 6B is an outline of a CC ′ cross section in FIG. FIG. The description of the same configuration as that of the above embodiment is omitted.

  In the first embodiment, the circulation flow path 11 is provided for each discharge port 9. In the present embodiment, the circulation flow path 11 is provided so as to connect the circulation flow paths 11 and communicate with the plurality of discharge ports 9. Specifically, a common ink inflow portion 32 and a common ink outflow portion 33 are provided so as to sandwich the plurality of discharge ports 9 arranged side by side, and the circulation flow path 11 extending from the common ink inflow portion 32 to the common ink outflow portion 33. However, it is provided so that all the ink reservoirs 10 communicate with each other.

  According to this embodiment, since the structure of the recording head is simplified by sharing a plurality of circulation channels 11 as one circulation channel, the discharge ports 9 can be arranged at high density. Note that the configuration of the present embodiment may be combined with the configuration of the second embodiment.

[Fifth Embodiment]
7A and 7B are schematic views of a recording head according to a fifth embodiment of the present invention. FIG. 7A is a plan view of the recording head, and FIG. 7B is a cross-sectional view taken along DD ′ in FIG. FIG. The description of the same configuration as that of the above embodiment is omitted.

  Unlike the above-described embodiment, the discharge port plate 18 is provided with two rows in which a plurality of discharge ports 9 are arranged. The individual liquid chamber 8 provided corresponding to the discharge port 9 is connected to the common ink inflow portion 32 via the throttle portion 13. The common ink inflow portion 32 is provided for each row of the ejection ports 9, and is connected to another common ink inflow portion 32 for each row of the ejection ports 9.

  In addition to the common ink inflow portion 32, the flow path forming portion 14 is provided with a common ink outflow portion 33 between the rows of the ejection ports 9. In addition, a circulation channel 11 is provided from the ink reservoir 10 provided corresponding to the ejection port 9 to the common ink outflow portion 33, and all the circulation channels 11 are connected to the common ink outflow portion 33. .

  Each common ink inflow portion 32 and common ink outflow portion 33 are connected to an ink tank 6 ″ provided outside the recording head. The ink flow path 22 between the ink tank 6 ″ and each common ink inflow portion 32 and common ink outflow portion 33 is provided with a pump 5 that is an ink flow means.

  In the present embodiment, the ink tank 6 ″ passes through the common ink inflow portion 32, the throttle portion 13, the individual liquid chamber 8, the discharge port 9, the ink reservoir 10, the circulation channel 11, and the common ink outflow portion 33. Ink always circulates at 6 ″.

  In the embodiment described above, the ink flowing through the ejection port 9 and the ink flowing through the circulation channel 11 may interfere with each other at the position of the ink reservoir 10. In this embodiment, since the flow of ink flowing through the position of the ink reservoir 10 is only in one direction, the ink flows smoothly. Therefore, even if the plurality of ejection ports 9 communicate with the common ink outflow portion 33, it is possible to effectively suppress the occurrence of crosstalk from the adjacent ejection ports 9. Further, it is only necessary to provide one ink tank 6 ″, and the ink in one ink tank 6 ″ covers the ink used for recording and the ink that is constantly circulated to prevent evaporation. . Note that the configuration of the present embodiment may be combined with the configuration of the second embodiment.

  It is also possible to provide a plurality of sets of ejection port groups instead of providing one group of ejection port groups with two rows of ejection port arrays. In that case, what is necessary is just to apply said structure for every set.

  Further, the ink flow to be circulated to suppress evaporation flows from one of the common ink inflow portions 32 or the common ink outflow portion 33 and from the other of the common ink inflow portions 32 or the other of the common ink outflow portions 33. It should just flow out.

[Sixth Embodiment]
8A and 8B are schematic views of a recording head according to the sixth embodiment of the present invention. FIG. 8A is a plan view of the recording head, and FIG. 8B is a cross-sectional view taken along the line EE ′ of FIG. FIG. The description of the same configuration as that of the above embodiment is omitted.

  Unlike the fifth embodiment, the recording head according to the present embodiment includes an ink reservoir 10 facing each of the ejection ports 9 in the row of one ejection port 9 of the ink reservoir 10 and the other ejection port 9 corresponding thereto. An ink reservoir 10 facing each ejection port 9 in the row communicates with the circulation flow path 11. In addition, one of the two common ink inflow portions 32 in the fifth embodiment is a common ink outflow portion 33. The common ink inflow portion 32 and the common ink outflow portion 33 are respectively connected to the ink tank 6 ″. The ink flow path 22 between the ink tank 6 ″ and the common ink inflow portion 32 and the common ink outflow portion 33 is provided with a pump 5 that is an ink flow means.

  From the ink tank 6 ″, the common ink inlet 32, one individual liquid chamber 8, one ejection port 9, one ink reservoir 10, the circulation channel 11, the other ink reservoir 10, the other ejection port 9, and the other Ink always flows into the ink tank 6 ″ via the individual liquid chamber 8 and the common ink outflow portion 33.

  According to this embodiment, the print head may be provided with one common ink inflow portion 32 and one common ink outflow portion 33. Further, the circulation flow path 11 only needs to communicate the ink reservoir 10 facing each ejection port 9 of one ejection port 9 row and the corresponding ink reservoir 10 facing the other ejection port 9 row. Therefore, the structure of the recording head is simplified, and the discharge ports 9 can be arranged at high density. Note that the configuration of the present embodiment may be combined with the configuration of the second embodiment.

[Seventh Embodiment]
FIG. 9 is an enlarged sectional view of a recording head according to the seventh embodiment of the present invention. FIG. 10 is a plan view of the recording head of FIG. 11 is an enlarged schematic view of the vicinity of the ejection port 9 of the recording head of FIG. 9, FIG. 11 (a) is an enlarged view, and FIG. 11 (b) is an FF ′ cross section of FIG. 11 (a). FIG. 11C is a schematic view of the GG ′ cross section of FIG.

  Two rows in which a plurality of discharge ports 9 are arranged are provided inside the flow path forming portion 14 of the recording head of this embodiment. The individual liquid chamber 8 has a surface other than the discharge port plate 18 having the discharge port 9 provided corresponding to the individual liquid chamber 8 formed of the piezoelectric element 7, and is perpendicular to the discharge port plate 18. 7 separates the individual liquid chambers 8 from each other. The ejection port plate 18 is provided with an ink introduction port 16 and an ink outlet port 17 along the individual liquid chamber 8 at positions facing each other with the ejection port 9 in between. A spacer 51 is interposed between the discharge port plate 18 and the surface layer 14 ′ of the flow path forming unit 14 so as to surround a space including the discharge port 9, the ink introduction port 16, and the ink outlet port 17. The discharge port plate 18 and the surface layer 14 ′ of the flow path forming part 14 are connected. An opening 31 is provided at a position corresponding to the discharge port 9 of the surface layer 14 ′ of the flow path forming unit 14, and the ink reservoir 10 is provided between the discharge port 9 and the opening 31 of the circulation flow channel 11. Is provided. With this configuration, the circulation channel 11 is formed from the ink inlet 16 to the ink outlet 17 through the ink reservoir 10.

  When the pressure inside the individual liquid chamber 8 is changed by the piezoelectric element 7, ink is ejected from the ejection port 9, and recording is performed.

  Inside the flow path forming unit 14, a common ink inflow portion 32 is provided along the row of the ejection ports 9 at a position sandwiched between the rows of the ejection ports 9, and the inflow portion 32 across the row of the ejection ports 9. A common ink outflow portion 33 is provided along the row of the ejection ports 9 at a position opposite to. The common ink inflow portion 32 and the two common ink outflow portions 33 are connected to the ink tank 6 ″, and an ink flow path between the ink tank 6 ″, the common ink inflow portion 32, and the common ink outflow portion 33. 22 is provided with a pump 5 which is an ink flow means.

  The ink is always circulated from the ink tank 6 ″ to the ink tank 6 ″ through the common ink inflow portion 32, the individual liquid chambers 8, and the common ink outflow portion 33 by the pump 5.

  The flow of ink in the individual liquid chamber 8 will be described. As indicated by the arrow shown in FIG. 11B, a part of the ink flowing from the common ink inflow portion 32 flows toward the common ink outflow portion 33 in the individual liquid chamber 8. Other part of the ink flowing from the common ink inflow portion 32 flows out from the individual liquid chamber 8 through the ink outlet 16 to the circulation flow path 11 and again from the ink inlet 17 through the ink reservoir 10. Ink flows into the liquid chamber 8.

  The piezoelectric element 7 of the present embodiment is composed of a piezoelectric body typified by PZT (lead zirconate titanate), and such an ink discharge type recording head is called a shear mode type.

  When the piezoelectric body, which is the piezoelectric element 7 constituting a part of the individual liquid chamber 8, is deformed into a U shape by shear deformation, the pressure in the individual liquid chamber 8 changes and ink is ejected from the ejection port 9. Is done.

  In the recording head of the present embodiment, the circulation channel 11 is formed simply by forming the holes of the ink outlet 16 and the ink inlet 17 in the ejection port plate 18, so that the structure of the recording head can be simplified. In addition, it is possible to more effectively suppress the occurrence of crosstalk between adjacent discharge ports 9. Further, the flow of ink in the direction perpendicular to the cross section of the ejection port 9 can be controlled by the design of the ink introduction port 16, the ink outlet port 17, and the circulation channel 11. For example, as shown in FIGS. 12A and 12B, the ejection port 9 is used as the ink introduction port 16 or the ink outlet port 17, and as shown in FIGS. 13A and 13B, the ink is used. The opening area of the outlet 16 and the ink outlet 17 is configured to have a magnitude relationship. By doing in this way, the flow of the ink of the discharge port 9 can be made into arbitrary directions.

  In addition, it is possible to provide a plurality of sets instead of providing one set of discharge port sets in which two rows of discharge port arrays are formed as one set. In that case, what is necessary is just to apply said structure for every set.

  In addition, the flow of ink to be circulated to suppress evaporation flows from one of the common ink inflow portions 32 or the common ink outflow portion 33, and from the other of the common ink inflow portions 32 or the other of the common ink outflow portions 33. Just let it flow out.

[Eighth Embodiment]
FIG. 14 is an enlarged sectional view of a recording head according to the eighth embodiment of the present invention. FIG. 15 is a plan view of the recording head of FIG. 16 is an enlarged schematic view of the vicinity of the ejection port 9 of the recording head of FIG. 14, FIG. 16 (a) is an enlarged perspective view, and FIG. 16 (b) is an HH ′ cross section of FIG. 16 (a). FIG. 16C is a schematic view of the II ′ cross section of FIG.

  The present embodiment is a share mode type ink jet recording head, as in the seventh embodiment.

  The ink inlet 16 and the ink outlet 17 in the seventh embodiment are not provided in the ejection port plate 18. Further, the discharge ports 9 adjacent in the same row of discharge ports 9 are arranged so as to be positioned on the upstream side and the downstream side, respectively, with respect to the direction of ink flow in each individual liquid chamber 8. The inner surface of the surface layer 14 ′ and the discharge port plate 18 are provided in contact with each other. Adjacent ink reservoirs 10 are connected via a circulation channel 11 provided in the surface layer 14 ′ of the channel formation unit 14. In the present embodiment, unlike the seventh embodiment, the spacer 51 is not necessary.

  If the distance shifted to the upstream side and the downstream side of the adjacent discharge ports 9 increases, the pressure difference between the adjacent discharge ports 9 also increases. Therefore, the ink reservoir 10 connecting the adjacent ejection ports 9 and the ink in the circulation channel 11 can be flowed by the pump 5. In the description of the present embodiment, two adjacent discharge ports 9 are connected to each other, but three or more adjacent discharge ports 9 may communicate with each other.

  In the present embodiment, since the ink reservoir 10 and the circulation flow path 11 are formed on the surface layer 14 ′ of the flow path forming unit 14 and the adjacent discharge ports 9 are connected to each other, the structure is simpler than that of the seventh embodiment. Can be manufactured easily.

  In addition, it is also possible to provide a plurality of sets of discharge port groups instead of providing one set of two discharge port arrays. In that case, what is necessary is just to apply said structure for every set.

  In addition, the flow of the ink to be circulated may flow from one of the common ink inflow portions 32 or the common ink outflow portion 33 and out of the other of the common ink inflow portions 32 or the common ink outflow portion 33. That's fine.

  In the present invention, the ink reservoir 10 is provided so that the ink in the ink reservoir 10 is always circulated. Therefore, the number of the ink flow means for circulating the ink may be adjusted as appropriate. The direction of the flow may be changed as appropriate.

1 Recording head 6, 6 ′, 6 ″ ink tank 7 Piezoelectric element (energy generating element)
10 ink reservoir 14 flow path forming portion 14 'surface layer 18 discharge port plate 32 inflow portion 33 outflow portion

Claims (22)

A flow path forming portion having a discharge port plate having a plurality of discharge ports for discharging ink, and an individual liquid chamber provided for each of the discharge ports for supplying ink to the discharge port, and the individual liquid A recording apparatus having a recording head including an energy generating element that generates energy for ejecting ink contained in a chamber, and an ink tank,
The surface layer of the flow path forming part faces the outside of the discharge port plate,
Openings are respectively provided in the surface layer of the flow path forming portion at positions facing the discharge ports,
An ink reservoir is provided between the discharge port plate and the opening of the surface layer, and a circulation channel communicating with the ink reservoir is provided.
The opening area of the opening is larger than the opening area of the discharge port,
Both ends of the circulation flow path are connected to the inflow part and the outflow part to which the circulation flow path is connected, respectively.
The recording apparatus, wherein the inflow portion, the outflow portion, and the individual liquid chamber are connected to the ink tank.   The recording apparatus according to claim 1, wherein an ink tank connected to the inflow portion and the outflow portion is different from an ink tank connected to the individual liquid chamber.   The recording apparatus according to claim 1, wherein the circulation channel is provided for each of the discharge ports.   The recording apparatus according to claim 1, wherein a plurality of the circulation channels are connected to communicate with the plurality of ink reservoirs.   The discharge port plate is provided with at least one discharge port group in which two discharge port arrays in which a plurality of the discharge ports are arranged are provided, and one discharge port array and the other of the discharge port groups are provided. One of the outflow portion or the inflow portion is provided along the discharge port row between the discharge port row and faces one of the outflow portion or the inflow portion across the discharge port row. The inflow part or the other of the inflow part is provided at a position, and the circulation channel is connected to one of the outflow part or the inflow part from each ink reservoir, and the outflow part or the inflow part The recording apparatus according to claim 1, wherein the other is connected to the individual liquid chamber.   The discharge port plate is provided with at least one discharge port group provided with two discharge port arrays in which a plurality of the discharge ports are arranged, and along the discharge port array of the discharge port group, An outflow portion and the inflow portion are provided, and two rows of the discharge port arrays are arranged at positions sandwiched between the inflow portion and the outflow portion, and each of the circulation flow paths has one of the discharge channels. 2. The recording apparatus according to claim 1, wherein the ink reservoir facing each ejection port of the outlet row communicates with the ink reservoir facing each ejection port of the other ejection port row corresponding thereto. A discharge port plate provided with at least one discharge port set including two discharge port arrays in which a plurality of discharge ports for discharging ink are arranged, and provided for each of the discharge ports; A recording head having a flow path forming portion having an individual liquid chamber for supplying the ink to the outlet, and an ink tank;
The surface layer of the flow path forming part faces the outside of the discharge port plate,
The discharge port plate is provided with an introduction port and a discharge port along the individual liquid chamber at positions facing each other across the discharge port,
The individual liquid chamber is provided perpendicular to the discharge port plate, delimited by a wall formed by an energy generating element, and covered by the discharge port plate,
An opening having an opening area larger than the opening area of the discharge port is provided at a position facing the discharge port of the surface layer of the flow path forming unit,
The discharge port plate and the surface layer are connected via a spacer provided so as to surround a space including the discharge port, the introduction port, the discharge port, and the opening. And a circulation channel is formed between the surface layer and the surface layer,
One of the outflow portion or the inflow portion is provided between the one discharge port row and the other discharge port row along the discharge port row, and the outflow portion or the inflow portion is sandwiched between the discharge port rows. The inflow portion or the other of the inflow portion is provided at a position facing one of the
The recording apparatus, wherein the inflow portion and the outflow portion are connected to the ink tank.   The recording apparatus according to claim 7, wherein the discharge port is shared with the introduction port or the discharge port.   The recording apparatus according to claim 7, wherein an opening area of the introduction port is different from an opening area of the outlet port. A discharge port plate provided with at least one discharge port set including two discharge port arrays in which a plurality of discharge ports for discharging ink are arranged, and provided for each of the discharge ports; A recording head having a flow path forming portion having an individual liquid chamber for supplying the ink to the outlet, and an ink tank;
The discharge port plate is provided in contact with the surface layer of the flow path forming part,
The individual liquid chamber is provided perpendicular to the discharge port plate, delimited by a wall formed by an energy generating element, and covered by the discharge port plate,
The discharge ports are arranged such that adjacent discharge ports in the same discharge port row are positioned on the upstream side and the downstream side with respect to the ink flow in each individual liquid chamber, respectively.
An opening having an opening area larger than the opening area of the discharge port is provided at a position facing the discharge port of the surface layer of the flow path forming unit, and the adjacent opening is connected to form a circulation flow path. Has been
One of the outflow portion or the inflow portion is provided between the one discharge port row and the other discharge port row along the discharge port row, and the outflow portion or the inflow portion is sandwiched between the discharge port rows. The inflow portion or the other of the inflow portion is provided at a position facing one of the
The recording apparatus, wherein the inflow portion and the outflow portion are connected to the ink tank.   11. The ink flowing means is provided between the ink tank and the inflow portion and / or between the ink tank and the outflow portion, respectively. 11. Recording device.   The recording apparatus according to claim 1, wherein the energy generating element is a piezoelectric element. A flow path forming unit having a discharge port plate having a plurality of discharge ports for discharging ink, and an individual liquid chamber for supplying the ink to the discharge port, provided for each of the discharge ports; and Ink in a recording apparatus having a recording head provided with an energy generating element that generates energy for discharging ink stored in the individual liquid chamber, an ink tank, and a flow means for flowing the ink in the ink tank. A method for suppressing thickening,
The discharge port plate is arranged so that the surface layer of the flow path forming part faces the outside of the discharge port plate,
The discharge port plate and the surface layer are each provided with an opening having an opening area larger than the opening area of the discharge port at a position facing the discharge port of the discharge port plate of the surface layer of the flow path forming unit. Forming an ink reservoir between each of the openings and a circulation channel communicating with the ink reservoir,
A method of suppressing ink thickening, wherein the fluid means causes the ink in the ink tank to flow into the circulation channel.   The method according to claim 13, wherein the circulation flow path is provided for each ejection port.   The method according to claim 13, wherein the plurality of circulation channels are connected to communicate with the plurality of ink reservoirs. Providing at least one discharge port set provided with two rows of discharge port rows in which a plurality of the discharge ports are arranged on the discharge port plate;
The ink is caused to flow into the individual liquid chamber from an inflow portion provided along the discharge port row between the one discharge port row and the other discharge port row of the discharge port group. 14. The ink increase according to claim 13, wherein the ink is supplied to the ink reservoir and further to the outflow portion provided at a position opposite to the inflow portion of the discharge port array of the discharge port set via the circulation channel. A method of suppressing viscosity. Providing at least one discharge port set provided with two rows of discharge port rows in which a plurality of the discharge ports are arranged on the discharge port plate;
The ink reservoirs facing the respective ejection ports of one of the ejection port arrays and the ink reservoirs opposed to the ejection ports of the other ejection port array corresponding to the circulation flow path are arranged as one of the ejection ports. In communication with the ink reservoirs at corresponding positions in the row and the other ejection port row,
The ink that has flowed from the inflow portion provided along the discharge port row of the discharge port set to the individual liquid chambers in one row is caused to flow to the ink reservoir via the discharge port, and the circulation channel Through the discharge port and the individual liquid chamber, and then through the discharge port and the individual liquid chamber to the outflow portion provided at a position opposite to the inflow portion. A method for suppressing the thickening of the ink according to claim 13. A discharge port plate provided with at least one discharge port set including two discharge port arrays in which a plurality of discharge ports for discharging ink are arranged, and provided for each of the discharge ports; Increasing the viscosity of ink in a recording apparatus having a recording head having a flow path forming portion having an individual liquid chamber for supplying the ink to an outlet, an ink tank, and a flow means for flowing ink in the ink tank. A method of suppressing,
The discharge port plate is arranged so that the surface layer of the flow path forming part faces the outside of the discharge port plate,
The individual liquid chamber is formed by a wall formed by an energy generating element and arranged perpendicularly to the discharge port plate and the discharge port plate,
The discharge port plate is provided with an introduction port and a discharge port at positions facing each other across the discharge port,
An opening having an opening area larger than the opening area of the discharge port is provided at a position facing the discharge port of the surface layer of the flow path forming unit,
By connecting the surface layer and the discharge port plate via a spacer provided so as to surround a space including the discharge port, the introduction port, the discharge port, and the opening, the discharge port plate And forming a circulation channel between the surface layer and the surface layer,
In the discharge port group, from the inflow portion formed along the discharge port row at a position sandwiched between the one discharge port row and the other discharge port row of the flow path forming unit, the ink tank Ink is allowed to flow in, the ink is allowed to flow from the individual liquid chamber to the circulation channel through the inlet, and returned to the individual liquid chamber via the outlet, and the inflow is sandwiched by the ejection port array. A method of suppressing the increase in the viscosity of the ink, which is caused to flow out to an outflow portion formed along the ejection port array at a position facing the portion.   By making the discharge port and the introduction port or the discharge port in common, the ink in the circulation channel flows into the individual liquid chamber through the discharge port, or the ink in the individual liquid chamber is used. The method for suppressing ink thickening according to claim 18, wherein the ink is caused to flow through the discharge port to the circulation channel.   By making the opening area of the inlet port larger than the opening area of the outlet port, a part of the ink in the circulation channel flows into the individual liquid chamber through the discharge port, or 19. The ink increase according to claim 18, wherein a part of the ink in the individual liquid chamber is caused to flow to the circulation channel through the ejection port by making the opening area larger than the opening area of the introduction port. A method of suppressing viscosity. A discharge port plate provided with at least one discharge port set including two discharge port arrays in which a plurality of discharge ports for discharging ink are arranged, and provided for each of the discharge ports; Ink thickening in a recording apparatus having a recording head having a flow path forming portion having an individual liquid chamber for supplying the ink to the outlet, an ink tank, and a flow means for flowing the ink in the ink tank A method of suppressing
The individual liquid chamber is formed by a wall formed by an energy generating element and arranged perpendicularly to the discharge port plate and the discharge port plate,
The discharge ports are arranged in the individual liquid chambers so as to be positioned on the upstream side and the downstream side with respect to the ink flow, respectively.
The discharge port plate is brought into contact with the inner surface of the surface layer of the flow path forming portion, and an opening having an opening area larger than the opening area of the discharge port is provided at a position facing the discharge port of the surface layer. Forming a circulation flow path so that the adjacent openings are connected,
Ink of the ink tank is supplied to the individual liquid chamber from an inflow portion formed along the discharge port array at a position sandwiched between the one discharge port array and the other discharge port array of the flow path forming unit. The ink is allowed to flow from one individual liquid chamber to the other individual liquid chamber via the one opening, the circulation channel, and the other opening, and further sandwich the ejection port array. A method of suppressing the increase in the viscosity of the ink, which is caused to flow out to an outflow portion formed along the ejection port array at a position facing the inflow portion.   The method for suppressing ink thickening according to any one of claims 13 to 21, wherein the amount of the ink flowing in the circulation flow path is made larger than the amount of the ink evaporated.

Images