KR20170083503A - Liquid discharge apparatus and liquid discharge head - Google Patents

Abstract

The liquid ejection apparatus includes a plurality of ejection openings configured to eject liquid, a plurality of pressure chambers having therein a recording element configured to generate energy used to eject the liquid, and a plurality of pressure chambers communicating with the plurality of ejection openings through the ejection channels, respectively A liquid ejection head including a recording element substrate including a pressure chamber, a liquid supply channel configured to supply liquid to the plurality of pressure chambers, and a liquid recovery channel configured to recover liquid from the plurality of pressure chambers, And a tank configured to store the liquid. The plurality of pressure chambers communicate with the liquid supply channel and the liquid recovery channel so that the liquid flows through the plurality of pressure chambers and the relative dielectric constant? _R of the liquid stored in the tank satisfies the relationship of? _R ? 65 .

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liquid ejection apparatus,

The present disclosure relates to a liquid discharge device and a liquid discharge head.

Volatile components in the liquid discharged from the discharge port evaporate in the liquid discharge head that discharges liquid such as ink from the discharge port and causes liquid to change in the vicinity of the discharge port to cause a change in discharge speed of the discharged liquid droplet, .

There is a known method for circulating the ink supplied to the liquid discharge head along the circulation path as a countermeasure for the liquid enrichment phenomenon. Japanese Patent Application Laid-Open No. 2002-355973 discloses a liquid discharge head which suppresses clogging of the discharge port due to evaporation of liquid from the discharge port by circulating the liquid in the channel formed between the member on which the discharge port is formed and the substrate on which the heating resistance element is formed. .

When the rest period after the ejection operation is long, the increased viscosity of the liquid near the ejection opening becomes prominent, and the solid component in the liquid can be solidified near the ejection opening. Thus, the solid component increases the fluid resistance when the liquid passes through the discharge port in the initial liquid discharge after rest, which can lead to defective discharge. However, in the liquid discharge head disclosed in Japanese Patent Application Laid-Open No. 2002-355973, no consideration is given to such defect discharge. Therefore, defective discharge occurring in the initial liquid discharge after the rest may cause deterioration of image quality.

It has been found desirable to provide a liquid discharge head and a liquid discharge device capable of forming a high-resolution and high-quality image.

The liquid ejection apparatus includes a plurality of ejection openings configured to eject liquid, a plurality of pressure chambers having therein a recording element configured to generate energy used to eject the liquid, and a plurality of pressure chambers communicating with the plurality of ejection openings through the ejection channels, respectively A liquid discharge head having a recording element substrate including a pressure chamber, a liquid supply channel configured to supply liquid to the plurality of pressure chambers, and a liquid recovery channel configured to recover liquid from the plurality of pressure chambers; And a tank configured to recover the liquid supplied to the liquid discharge head. A plurality of pressure chambers communicate with the liquid supply channel and the liquid recovery channel (19), so that the liquid flows through the plurality of pressure chambers. The relative dielectric constant? _R of the liquid stored in the tank satisfies the relationship of? _R ? 65.

The liquid discharge head includes a discharge port configured to discharge liquid; A recording element configured to generate energy used to eject liquid; A pressure chamber having a recording element therein; A liquid supply channel configured to supply liquid to the pressure chamber; And a liquid recovery channel configured to recover liquid from the pressure chamber. The liquid dielectric constant (ε _r) is satisfied a relationship of ε _r ≤ 65 is circulated through a liquid supply channel, a pressure chamber and the liquid collection channels.

The relative dielectric constant of the liquid can be lowered according to the liquid discharge device and the liquid discharge head described above and consequently the stagnation of the solid content near the periphery of the discharge port can be suppressed even after stopping the discharge operation for a specific amount of time. Therefore, even in the case of a liquid having a large amount of solid content, defective discharge can be suppressed in the initial release of the liquid after the rest, thereby suppressing deterioration of the image quality.

Other features of the invention will become apparent from the following description of an illustrative embodiment with reference to the accompanying drawings.

1 is a perspective view illustrating an inkjet recording apparatus according to a first application example.
2 is a schematic view illustrating a first circulation path in the first application example;
3 is a schematic view illustrating a second circulation path in the first application example;
4A and 4B are perspective views of the liquid discharge head according to the first application example.
5 is an exploded perspective view of the liquid discharge head according to the first application example.
6A to 6F are plan views illustrating the first to third channel members according to the first application example.
7 is an enlarged perspective view of a part of the channel member of the first application example;
8 is a cross-sectional view taken along line VIII-VIII in Fig.
9A and 9B are views illustrating a discharge module according to the first application example, wherein FIG. 9A is a perspective view and FIG. 9B is an exploded view.
10A and 10C are plan views of the recording element substrate according to the first application example.
11 is a perspective view illustrating the cross-section XI-XI of FIG. 10A.
12 is a plan view showing a partially enlarged view of an adjacent portion of the recording element substrate according to the first application example.
13A and 13B are perspective views of the liquid discharge head according to the second application example.
14 is an exploded perspective view of the liquid discharge head according to the second application example.
15A to 15E are plan views of first and second channel members constituting the channel member according to the second application example.
16 is an enlarged perspective view of a part of the channel member of the second application example.
17 is a cross-sectional view taken along line XVII-XVII in Fig.
18A and 18B are views illustrating a discharge module according to the second application example, wherein FIG. 18A is a perspective view and FIG. 18B is an exploded view.
19A and 19C are plan views of the recording element substrate according to the second application example.
20 is a perspective view illustrating an inkjet recording apparatus according to a second application example.
Figs. 21A to 21C are views illustrating a main portion of the liquid discharge head according to the first embodiment, wherein Fig. 21A is a plan view, Fig. 21B is a sectional view, and Fig. 21C is a perspective view.
22 is an enlarged cross-sectional view of the vicinity of the discharge port of the liquid discharge head.
23 is a graph for explaining the relationship between the head dimension and the flow mode.
Figure 24 is a graph illustrating the identified results of the relationship between flow mode and head dimensions.
25A to 25D are diagrams illustrating a circulating flow in the discharge port.
26A to 26C are diagrams illustrating the concentration of ink in the discharge port.
27A to 27D are diagrams illustrating the concentration distribution of the solvent in the discharge port and the concentration distribution of the pigment.
28 is a graph depicting a discharge speed with respect to the number of droplets ejected after a rest.
29A to 29C are graphs depicting the ejection speed with respect to the number of droplets ejected after a rest.
30 is a sectional view of the liquid discharge head according to the second embodiment.
31A and 31B are plan views of a liquid discharge head according to the third embodiment.
32 is a perspective view of the inkjet recording apparatus according to the first application example.
33 is a diagram illustrating a third circulation path.
34A and 34B are views illustrating a liquid discharge head according to the first application example.
35 is an exploded perspective view of the liquid discharge head according to the first application example.
36 is a schematic view of a channel member of the liquid discharge head according to the first application example.
37 is a diagram illustrating a recording apparatus according to a third application example.
38 is a diagram exemplifying a fourth circulation path.
39A and 39B are views illustrating a liquid discharge head according to a third application example.
40A to 40C are views illustrating a liquid discharge head according to a third application example.

The application examples and the embodiments will be described with reference to the accompanying drawings. The first to third application examples will be described first, and then an embodiment will be described. However, it should be understood that the following description does not limit the scope of the invention. As an example, a thermal system in which bubbles are generated by a heating element and liquid is ejected is suggested in this application example, but this disclosure can be applied to a liquid ejection head employing a piezoelectric system or various other types of liquid ejection systems have.

Although the application example relates to an ink jet recording apparatus (or simply "recording apparatus") in the form in which liquid such as ink circulates between the tank and the liquid discharge head, other forms can be used as well. As an example, instead of the ink circulation, a configuration in which two different tanks are provided on the upstream side of the liquid discharge head and on the downstream side, and the ink in the pressure chamber flows by moving the ink from one tank to the other tank Can be used. The application example relates to a so-called line head having a length corresponding to the width of the recording medium, but the embodiment may also be a so-called serial liquid ejection head which records while scanning on the recording medium. An example of a serial liquid discharge head is one having, but not limited to, one substrate for each of black ink recording and color ink recording. An array in which a short line head is formed shorter than the width of the recording medium and a plurality of recording element substrates are arranged so as to overlap the ejection orifices in the ejection orifice row direction and are scanned on the recording medium can be formed.

First application example

Explanation of inkjet recording apparatus

Fig. 1 illustrates a schematic configuration of an ink-jet recording apparatus 1000 (hereinafter, simply referred to as "recording apparatus") for ejecting liquid, particularly, ink-ejecting recording. The recording apparatus 1000 is a line recording apparatus which includes a conveying unit 1 for conveying the recording medium 2 and a line-type (page-wide) liquid ejecting head 2 which is arranged substantially orthogonal to the conveying direction of the recording medium 2. [ (3), and performs a single pass continuous recording while conveying a plurality of recording media (2) continuously or intermittently. The recording medium 2 is not limited to a cut sheet but may be a continuous roll sheet. The liquid discharge head 3 is capable of full color printing by cyan, magenta, yellow and black (abbreviated as "CMYK") inks. The liquid discharge head 3 has a liquid supply unit serving as a supply path for supplying liquid to the liquid discharge head 3, a main tank and a buffer tank (see Fig. 2) connected by fluid connection. The liquid discharge head 3 is also electrically connected to an electric control unit, which transmits power and discharge control signals to the liquid discharge head 3. The liquid path and the electric signal path in the liquid discharge head 3 will be described later.

Explanation of the first circulation route.

2 is a schematic view illustrating a first circulation path as a first type of circulation path applied to the recording apparatus of the present application example. 2 is a diagram exemplifying a first circulation pump (high pressure side) 1001, a first circulation pump (low pressure side) 1002, and a buffer tank 1003, which are connected by fluid connection as a flow unit. Although FIG. 2 only illustrates the path through which one color ink flows in the CMYK ink flow for the sake of brevity of description, there is actually a circulating path for the four colors provided in the recording apparatus main unit and the liquid discharge head 3 . The buffer tank 1003 serving as a sub tank connected to the main tank 1006 is provided with an atmospheric communication opening (not shown), whereby the inside and the outside of the tank communicate with each other and the bubbles in the ink are discharged to the outside . Buffer tank 1003 is also connected to supplemental pump 1005. [ When ink is consumed in the liquid discharge head 3 by discharging (discharging) ink from the discharge port of the liquid discharge head by discharging the ink to perform recording, suction count, etc., the replenishment pump 1005 supplies the ink to the main tank 1006, The same amount of ink as that consumed from the ink tank 1003 is sent to the buffer tank 1003.

The first circulation pumps 1001 and 1002 serve to extract liquid from the liquid connector 111 of the liquid discharge head 3 and to flow the liquid to the buffer tank 1003. The first circulation pumps 1001 and 1002, which function as a flow unit for flowing liquid through the liquid discharge head 3, are preferably positive displacement pumps having a quantitative fluid transfer function. Specific examples may include tube pumps, gear pumps, diaphragm pumps, syringe pumps, and the like. Arrangements in which a constant flow is ensured by disposing a common constant flow valve and a relief valve at the outlet of the pump may be used. The first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002 are configured such that a certain amount of ink is supplied to the common supply channel 211 and the common recovery channel (212). The amount of the flow is preferably set to a level or more so that the temperature difference between the recording element substrates 10 of the liquid discharge head 3 does not affect the quality of the recorded image. On the other hand, when the flow rate is set to be excessively high, the influence of the pressure drop of the channel in the liquid discharge unit 300 causes an excessive large difference in negative pressure between the recording element substrates 10, do. Therefore, it is preferable that the flow rate is set in consideration of the temperature difference between the recording element substrates 10 and the negative pressure difference.

The negative pressure control unit 230 is provided between the path of the liquid discharge unit 300 and the second circulation pump 1004. The negative pressure control unit 230 controls the pressure of the downstream side (that is, on the side of the liquid discharge unit 300) from the negative pressure control unit 230 to a predetermined constant pressure even when the flow rate of the circulation system fluctuates due to the difference in duty upon recording. To be maintained. Any mechanism can be used as the two pressure regulating mechanisms constituting the negative pressure control unit 230 if the downstream pressure from itself can be controlled to fluctuate within a predetermined range centered on the desired set pressure. As an example, a mechanism equivalent to a so-called "decompression regulator" can be used. In the case of using the decompression regulator, the upstream side of the negative pressure control unit 230 is preferably pushed by the second circulation pump 1004 through the liquid supply unit 220 as illustrated in Fig. This makes it possible to suppress the influence of the head pressure on the liquid discharge head 3 of the buffer tank 1003 with respect to the liquid discharge head 3 so that a wider freedom degree of the layout of the buffer tank 1003 of the recording apparatus 1000 Lt; / RTI > It is sufficient that the second circulation pump 1004 has a specific heading pressure or higher within a range of the circulating flow pressure of the ink used when driving the liquid discharge head 3, and a turbo pump, a volumetric pump, or the like can be used. Specifically, a diaphragm pump or the like can be used. Alternatively, by way of example, a water head tank arranged with a specific head difference to the negative pressure control unit 230 may be used instead of the second circulation pump 1004. [

As illustrated in FIG. 2, the negative pressure control unit 230 has two pressure regulating mechanisms, which are set at different control pressures with respect to each other. 2) and the relative low-pressure setting side (indicated by L in Fig. 2) of the two negative pressure regulating mechanisms are connected to the liquid supply unit 220 via the liquid supply unit 220, The supply channel 211 and the common recovery channel 212. [ The liquid discharge unit 300 is provided with an individual supply channel 213 and an individual recovery channel 214 communicating between the common supply channel 211, the common recovery channel 212 and the recording element substrate 10. [ A flow occurs due to the individual supply channels 213 communicating with the common supply channel 211 and the common recovery channel 212 and a part of the liquid flows from the common supply channel 211 to the inside of the recording element substrate 10 Channel, and to the common collection channel 212 (indicated by arrows in FIG. 2). The reason is that the pressure regulating mechanism H is connected to the common supply channel 211 and the pressure regulating mechanism L is connected to the common recovery channel 212 so that a pressure difference is generated between the two common channels.

A part of the liquid passes through the recording element substrate 10 while the liquid is generated in the liquid discharge unit 300 and liquid flows through each of the common supply channel 211 and the common collecting channel 212. [ The heat generated in the recording element substrate 10 can be discharged from the recording element substrate 10 to the outside by the flow through the common supply channel 211 and the common collecting channel 212. [ This configuration also allows an ink flow to be generated in the pressure chambers and the ejection openings which are not used for recording while the recording is performed by the liquid ejection head 3, so that the enrichment of the ink in such a portion can be suppressed have. In addition, enriched ink and foreign matter in the ink can be discharged to the common recovery channel 212. [ The liquid discharge head 3 according to this application example can record at high speed with high image quality.

Explanation of the second circulation route.

3 illustrates a second circulation path, which is a circulation path different from the above-described first circulation path, for the circulation path applied to the recording apparatus according to the present application example. The main difference with respect to the above-described first circulation path is that both of the two pressure regulating mechanisms constituting the negative pressure control unit 230 are configured to regulate the upstream pressure from the negative pressure control unit 230 to a certain range And to have a mechanism for controlling it to fluctuate within a certain range. This mechanism is a mechanical part having an action equivalent to a so-called "back pressure regulator". The other difference is that the second circulation pump 1004 acts as a negative pressure source for depressurizing the downstream side from the negative pressure control unit 230. [ The other difference is that the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002 are disposed on the upstream side of the liquid discharge head 3 and the negative pressure control unit 230 is disposed on the upstream side of the liquid discharge head 3. [ (3).

The negative pressure control unit 230 of the second circulation path functions as follows. That is, the negative pressure control unit 230 controls the pressure fluctuation on the upstream side (i.e., on the side of the liquid discharge unit 300) itself even when the flow rate fluctuates due to the difference in duty during recording by the liquid discharge head 3 And is kept within a certain range centered on the previously set pressure. The downstream side of the negative pressure control unit 230 is preferably pushed by the second circulation pump 1004 via the liquid supply unit 220 as illustrated in Fig. This provides a wider selection range for the layout of the buffer tank 1003 in the recording apparatus 1000 by making it possible to suppress the influence of the head of the buffer tank 1003 on the liquid discharge head 3. Alternatively, by way of example, a water head tank arranged with a specific head difference to the negative pressure control unit 230 may be used instead of the second circulation pump 1004. [

The negative pressure control unit 230 has two pressure control mechanisms, which are set at different control pressures with respect to each other as illustrated in FIG. 3 in the same manner as in the first application example. 3) and the relative low-pressure setting side (indicated by L in Fig. 3) of the two negative pressure regulating mechanisms are connected to the common electrode of the liquid discharge unit 300 via the liquid supply unit 220, The supply channel 211 and the common recovery channel 212. [ The pressure of the common supply channel 211 is relatively higher than the pressure of the common recovery channel 212 by the two negative pressure regulating mechanisms. A flow occurs and the ink flows from the common supply channel 211 to the common return channels 212 through the individual channels 213 and 214 and the inner channels of the recording element substrate 10 Displayed). Therefore, the second circulation path produces the same ink flow state as that of the first circulation path in the liquid discharge unit 300, but has two advantages different from the case of the first circulation path.

One advantage is that the negative pressure control unit 230 is disposed on the downstream side of the liquid discharge head 3 in the second circulation path so that the dust and foreign matter generated in the negative pressure control unit 230 may flow into the head There is little. A second advantage is that the maximum value of the required flow rate supplied from the buffer tank 1003 to the liquid discharge head 3 can be smaller in the second circulation path than in the case of the first circulation path. The reason for this is as follows. The total flow rate in the common supply channel 211 and the common recovery channel 212 during circulation during write standby is denoted by A. [ The value of A is defined as a minimum flow rate required to maintain the temperature difference of the liquid discharge unit 300 within a preferable range when temperature control of the liquid discharge head 3 is performed during recording standby. The ejection flow rate when ink is ejected from all the ejection openings of the liquid ejection unit 300 (full ejection) is defined as F. Therefore, in the case of the first circulation path (Fig. 2), the set flow rate of the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) The maximum value of the liquid supply amount to the discharge head 3 is A + F.

On the other hand, in the case of the second circulation path (Fig. 3), the liquid supply amount to the liquid discharge head 3 necessary for recording standby is the flow rate A. [ This means that the supply amount to the liquid discharge head 3 necessary for the entire discharge is the flow rate F. [ Therefore, in the case of the second circulation path, the total value of the set flow rate of the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side 1002), that is, The maximum value (A or F) of the required supply amount of the second circulation path is the maximum value (A + F) of the required supply amount of the first circulation path, As a result, the degree of freedom with respect to the circulating pump which can be applied becomes higher in the case of the second circulation path, so that a low-cost circulation pump with a simple structure can be used and, for example, The advantage of this is that the value of A or F is relatively large, which is more pronounced in the line head, and the cost of the line head (not shown) can be reduced. The longer the length in the longitudinal direction Innovation is useful.

However, the first circulation path is more advantageous than the second circulation path. That is, in the second circulation path, the flow rate flowing through the liquid discharge unit 300 at the time of recording standby is the maximum value, so that the lower the recording duty of the image, the larger the negative pressure is applied to the nozzle. Therefore, the channel width (the length in the direction perpendicular to the liquid flow direction) of the common supply channel 211 and the common collecting channel 212 is reduced in order to reduce the head width (the length of the liquid discharge head in the transverse direction) , This can lead to more impact of satellite droplets. The reason is that a high negative pressure is applied to the nozzle in a low duty image with good uniformity. On the other hand, in the case of the first circulation path, a high negative pressure is applied to the nozzles in the high duty imaging, so that any generated satellites are less visible, which is advantageous in that the effect on image quality is small. Which of these two circulation paths is more preferable can be selected in view of the specification (discharge flow rate (F), minimum circulation flow rate (A) and channel resistance in the head) of the liquid discharge head and recording apparatus main unit.

Description of the Third Circulation Route

33 is a schematic view illustrating a third circulation path as a first type of circulation path applied to the recording apparatus. Description of the same functions and configurations as those of the above-described first and second circulation paths will be omitted, and the differences will be mainly described.

The liquid is supplied to the inside of the liquid discharge head 3 at three positions in total at two positions in the middle of the liquid discharge head 3 and one end side of the liquid discharge head 3. The liquid passes from the common supply channel 211 through the pressure chamber 23 and is then recovered by the common recovery channel 212 and then from the recovery opening at the other end of the liquid discharge head 3 to the outside Respectively. The individual channels 213 and 214 communicate with the common supply channel 211 and the common recovery channel 212 and the pressure chamber 23 disposed within the recording element substrate 10 and the recording element substrate 10 is communicated with the individual supply channels 211, (213, 214). A part of the ink pumped by the first circulation pump 1002 flows from the common supply channel 211 to the common recovery channel 212 through the pressure chamber 23 in the recording element substrate 10 (Indicated by arrows in Fig. 33). This is because a pressure difference is formed between the pressure regulating mechanism H connected to the common supply channel 211 and the pressure regulating mechanism L connected to the common recovery channel 212, Channel 212 only.

Therefore, the flow of the liquid passing through the common recovery channel 212 and the flow from the common supply channel 211 to the common recovery channel 212 through the pressure chamber 23 of the recording element substrate 10, (300). The heat generated in the recording element substrate 10 can be discharged from the recording element substrate 10 to the outside by the flow from the common supply channel 211 to the common recovery channel 212 while suppressing an increase in pressure loss . Further, in accordance with the circulation path, the number of pumps functioning as the liquid transportation unit can be reduced as compared with the first and second circulation paths described above.

Description of the configuration of the liquid discharge head

The configuration of the liquid discharge head 3 according to the first application example will be described. 4A and 4B are perspective views of the liquid discharge head 3 according to the present application example. The liquid ejection head 3 is a line type liquid ejection head in which 15 recording element substrates 10 on which the recording element substrates 10 can eject inks of four colors of C, M, Y and K are arranged in a straight line (In-line layout). 4A, the liquid discharge head 3 includes a recording element substrate 10, an input terminal 91 electrically connected to the flexible printed circuit board 40 via the electric wiring substrate 90, And a power supply terminal 92. The input terminal 91 and the power supply terminal 92 are electrically connected to the control unit of the recording apparatus 1000 and supply a discharge drive signal and power necessary for discharge to the recording element substrate 10, respectively. The integration of the wirings into the electric wiring substrate 90 by the electric circuit enables the number of the input terminals 91 and the electric power supply terminals 92 to be reduced as compared with the number of the recording element substrates 10. [ This makes it possible to reduce the number of electrical connection portions to be removed at the time of replacing the liquid discharge head 3 or in assembling the liquid discharge head 3 to the recording apparatus 1000. The liquid connection portion 111 provided at both ends of the liquid discharge head 3 is connected to the liquid supply system of the recording apparatus 1000, as shown in Fig. 4B. Thus, four colors of CMYK ink are supplied to the liquid discharge head 3, and the ink that has passed through the liquid discharge head 3 is recovered to the supply system of the recording apparatus 1000. [ In this way, the ink of each color can circulate the path of the recording apparatus 1000 and the path of the liquid discharge head 3.

Fig. 5 illustrates an exploded perspective view of the components and units constituting the liquid discharge head 3. Fig. The liquid discharge unit 300, the liquid supply unit 220 and the electric wiring substrate 90 are attached to the case 80. [ 3) is provided in the liquid supply unit 220 and is provided with a filter 221 for each color in communication with each opening of the liquid connection portion 111 to remove foreign matter in the supplied ink, (Figs. 2 and 3) are provided inside the liquid supply unit 220. Fig. The two liquid supply units 220 each have a filter 221 for two colors. The liquid that has passed through the filter 221 is supplied to each of the negative pressure control units 230 provided in the corresponding liquid supply unit 220. Each of the negative pressure control units 230 is a unit consisting of a pressure control valve for each of its colors and is provided with a supply of the recording apparatus 1000 that occurs due to the fluctuation of the flow rate of the liquid, System (a supply system on the upstream side of the liquid discharge head 3). Therefore, the negative pressure control unit 230 can stabilize the variation of the negative pressure on the downstream side (the liquid discharge unit 300 side) thereof within a specific range. Each negative pressure control unit 230 for each color has two built-in pressure control valves as described in FIG. These two pressure regulating valves are respectively set to different control pressures. In the case of the high-pressure side, the common supply channel 211 in the liquid discharge unit 300 and the low- And communicates with the liquid supply unit 220.

The case 80 is configured to include a liquid discharge unit support member 81 and an electric wiring board support member 82 and supports the liquid discharge unit 300 and the electric wiring substrate 90, In order to ensure the rigidity. The electric wiring substrate support member 82 is for supporting the electric wiring substrate 90 and is fixed by screwing to the liquid discharge unit support member 81. The liquid ejection unit support member 81 functions to correct warping and deformation of the liquid ejection unit 300 and thus suppresses the unevenness of the recorded matter by ensuring the relative positional accuracy of the plurality of recording element substrates 10. [ Therefore, it is preferable that the liquid discharge unit support member 81 has sufficient stiffness. Examples of suitable materials include metal materials such as stainless steel and aluminum and ceramics such as alumina. The liquid discharge unit support member 81 has openings 83 and 84 into which the engaging rubber member 100 is inserted. The liquid supplied from the liquid supply unit 220 passes through the bonded rubber member 100 and is guided to the third channel member 70 which is a component constituting the liquid discharge unit 300. [

The liquid discharge unit 300 is constituted by a plurality of discharge modules 200 and a channel member 210 and the cover member 130 is attached to the surface of the liquid discharge unit 300 facing the recording medium. The cover member 130 is a member having a frame-shaped surface on which the long opening 131 is provided. The recording element substrate 10 included in the ejection module 200 and the sealing portion 110 (FIG. 9) composed of the sealing material are exposed from the opening 131 as illustrated in FIG. The frame portion of the periphery of the opening 131 serves as a contact surface for the cap member which covers the liquid discharge head 3 during recording standby. Therefore, by covering the periphery of the opening 131 with an adhesive, a sealant, a filling member, or the like to fill the gap and irregularities of the discharge port surface of the liquid discharge unit 300, a closed space is preferably formed when the lid is attached.

Next, the configuration of the channel member 210 included in the liquid discharge unit 300 will be described. The channel member 210 is an article formed by laminating the first channel member 50, the second channel member 60, and the third channel member 70. The channel member 210 is a channel member that distributes the liquid supplied to each of the discharge modules 200 from the liquid supply unit 220 and returns the liquid recirculated from the discharge module 200 to the liquid supply unit 220. The channel member 210 is fixed to the liquid discharge unit support member 81 by a screw, thereby suppressing distortion and deformation of the channel member 210.

6A to 6F are views illustrating the front and rear side portions of the channel members constituting the first to third channel members. 6A illustrates the side of the first channel member 50 on which the discharging module 200 is mounted and FIG. 6F illustrates the side of the third channel member 70 which comes into contact with the liquid discharging unit supporting member 81 do. The first channel member 50 and the second channel member 60 have channel member contact surfaces that engage each other as illustrated in Figs. 6B and 6C, respectively, and as illustrated in Figs. 6D and 6E, The same applies to the second channel member 60 and the third channel member 70. The common channel grooves 62 and 71 are formed on the second channel member 60 and the third channel member 70 which are coupled to each other. When they face each other, eight common channels extending in the longitudinal direction of the channel member Channel. This forms a set of common supply channels 211 and common collection channels 212 for each color in channel member 210 (FIG. 7). The communication port 72 of the third channel member 70 communicates with the hole in the coupling rubber member 100 to communicate with the liquid supply unit 220 by fluid connection. A plurality of communication ports 61 are formed on the bottom surface of the common channel groove 62 of the second channel member 60 and communicate with one end of the individual channel groove 52 of the first channel member 50. The communication port 51 is formed at the other end of the individual channel groove 52 of the first channel member 50 so as to communicate with the plurality of discharge modules 200 by the fluid connection through the communication port 51. These individual channel grooves 52 allow the channels to be integrated in the middle of the channel member.

The first to third channel members are preferably formed of a material which is corrosion resistant to liquid and has a low linear expansion coefficient. Exemplary suitable materials include alumina, a liquid crystal polymer (LCP) and a composite material (resin material), wherein the composite material is an inorganic filler such as fine silica particles or fibers such as polyphenyl sulfide (PPS), polysulfone Such as modified polyphenylene ether (PPE). The channel member 210 may be formed by laminating three channel members and adhering by using an adhesive, or when a composite resin material is selected as a material, three channel members may be joined by fusion.

Next, the connection relationship of the channels in the channel member 210 will be described with reference to FIG. 7 is a partially enlarged perspective view of the channel in the channel member 210 formed by joining the first to third channel members, as viewed from the side of the first channel member 50 on which the discharge module 200 is mounted. The channel member 210 has common supply channels 211 (211a, 211b, 211c and 211d) and common collecting channels 212 (212a, 212b, and 212c) extending in the longitudinal direction of the liquid discharge head 3, 212c, and 212d. A plurality of individual supply channels 213 (213a, 213b, 213c, and 213d) formed in the individual channel grooves 52 are connected to the common supply channels 211 of the respective colors via the communication ports 61. [ A plurality of individual recovery channels 214 (214a, 214b, 214c, 214d) formed in individual channel grooves 52 are connected to common color recovery channels 212 of each color via communication ports 61. [ This channel configuration allows ink to be incorporated in the recording element substrate 10 disposed in the middle of the channel member from the common supply channel 211 via the separate supply channels 213. [ In addition, the ink can be recovered from the recording element substrate 10 to the common recovery channel 212 via the individual recovery channel 214. [

8 is a cross-sectional view taken along line VIII-VIII of FIG. 7 illustrating how the individual recovery channels 214a and 214c communicate with the dispensing module 200 via the communication port 51. FIG. Although FIG. 8 illustrates only the individual recovery channels 214a and 214c, the individual supply channels 213 and the discharge module 200 communicate in the other cross section as illustrated in FIG. 10B) for supplying ink from the first channel member 50 to the recording element 15 provided in the recording element substrate 10 is supported by the recording element substrate 10 and the support Is formed in the member (30). A channel for recovering (recirculating) some or all of the liquid supplied to the recording element 15 to the first channel member 50 is formed on the recording element substrate 10 and the support member 30. [ The common supply channel 211 of each color is connected to the negative pressure control unit 230 (high pressure side) of the corresponding color via the liquid supply unit 220 and the common recovery channel 212 is connected via the liquid supply unit 220 And is connected to the negative pressure control unit 230 (low pressure side). The negative pressure control unit 230 generates a pressure difference between the common supply channel 211 and the common recovery channel 212. Therefore, in the liquid discharge head 3 according to the present application example in which channels are connected as illustrated in FIGS. 7 and 8, the common supply channel 211 → the individual supply channel 213 → the recording element substrate 10 → the individual recovery A flow for each color occurs in the order of channel 214 → common collection channel 212.

Description of Discharge Module

FIG. 9A illustrates a perspective view of one discharge module 200, and FIG. 9B shows an exploded view thereof. A method of manufacturing the discharging module 200 is as follows. First, the recording element substrate 10 and the flexible printed circuit board 40 are attached to the support member 30 in which the communication port 31 is formed in advance. Subsequently, the terminal 16 on the recording element substrate 10 is electrically connected to the terminal 41 on the flexible printed circuit board 40 by wire bonding, and thereafter the wire-bonded portion (electrical connection portion) Is covered and sealed with a sealant to form the sealing portion (110). The terminal 42 at the other end of the flexible printed circuit board 40 from the recording element substrate 10 is electrically connected to the connection terminal 93 (Fig. 5) of the electric wiring substrate 90. Fig. The supporting member 30 is a supporting member for supporting the recording element substrate 10 and is also a channel member communicating between the channel member 210 and the recording element substrate 10 by fluid connection. Therefore, the support member 30 should have a high degree of flatness and also be able to be coupled to the recording element substrate 10 with high reliability. Examples of suitable materials include alumina and resin materials.

Description of the structure of the recording element substrate

The structure of the recording element substrate 10 according to this application example will be described. 10A is a plan view of the side of the recording element substrate 10 on which the ejection orifices 13 are formed, FIG. 10B is an enlarged view of a portion indicated by XB in FIG. 10A, (10). The recording element substrate 10 has a discharge port forming member 12, and four discharge port rows corresponding to ink colors are formed in the discharge port forming member as shown in Fig. 10A. Hereinafter, it is mentioned that the direction in which the discharge orifice row in which the plurality of discharge orifices 13 are arranged will be referred to as the "discharge orifice row" direction.

The recording element 15, which is a heating element for generating energy used for ejecting the liquid, is disposed at a position corresponding to the ejection opening 13 as illustrated in Fig. 10B. The pressure chamber 23 accommodating the recording element 15 is isolated by the partition wall 22. The recording element 15 is electrically connected to the terminal 16 of Fig. 10A by electric wiring (not shown) provided in the recording element substrate 10. [ The recording element 15 is configured so that the liquid is boiled based on the pulse signal input from the control circuit of the recording apparatus 1000 via the electric wiring substrate 90 (Fig. 5) and the flexible printed circuit board 40 (Fig. 9) To generate heat. The force of foaming due to such boiling discharges the liquid from the discharge port (13). The liquid supply channel 18 extends along one side of each row of the ejection openings, and the liquid recovery channel 19 extends along the other side. The liquid supply channel 18 and the liquid recovery channel 19 are channels extending in the direction of the ejection orifice row provided in the recording element substrate 10 and are respectively connected to the ejection openings 13 and 17 via the supply port 17a and the recovery port 17b Communicate.

The sheet-like cover 20 is stacked on the rear surface from the surface of the recording element substrate 10 on which the ejection orifices 13 are formed and the cover 20 is stacked on the rear surface of the recording element substrate 10, as illustrated in Figs. 10C and 11, And has a plurality of openings (21) communicating with the channels (18) and the liquid recovery channel (19). Three openings 21 are provided in the cover 20 for each liquid supply channel 18 and two openings 21 are provided for each liquid recovery channel 19. In this application, The opening 21 of the cover 20 communicates with the plurality of communication ports 51 illustrated in Fig. 6A, as illustrated in Fig. 10B. The cover 20 functions as a cover constituting a part of the side of the liquid recovery channel 19 and the liquid supply channel 18 formed in the substrate 11 of the recording element substrate 10 as shown in Fig. The cover 20 is preferably sufficiently corrosion resistant to the liquid and should have a high degree of precision regarding the shape and position of the opening 21 of the opening 21 from the standpoint of preventing color mixing. Therefore, a photosensitive resin material or a silicon plate, in which the opening 21 is formed by a photolithography process, is preferably used as a material for the cover 20. [ Thus, the cover 20 is for changing the pitch of the channel by the opening 21. [ The cover 20 is preferably thin, preferably formed of a film material, in view of the pressure drop.

Next, the flow of the liquid in the recording element substrate 10 will be described. Fig. 11 is a perspective view illustrating a section of the cover 20 and the recording element substrate 10 taken along the plane XI-XI in Fig. 10A. The recording element substrate 10 is formed by laminating a discharge port forming member 12 formed of a photosensitive resin and a substrate 11 formed of silicon (Si), and the cover 20 is bonded to the rear surface of the substrate 11. The recording element 15 is formed on the other surface side of the substrate 11 (Fig. 10B), and the liquid supply channel 18 extending along the discharge port row and the groove constituting the liquid recovery channel 19 are formed on the back surface side . The liquid supply channel 18 and the liquid recovery channel 19 formed by the substrate 11 and the cover 20 are respectively connected to the common supply channel 211 and the common collecting channel 212 in the channel member 210 , There is a pressure difference between the liquid supply channel 18 and the liquid recovery channel 19. When the liquid is discharged from the plurality of discharge ports 13 of the liquid discharge head 3 and recording is performed, the liquid flows as follows due to the differential pressure at the discharge port 13 which does not perform the discharge operation. That is, the ink in the liquid supply channel 18 provided in the substrate 11 flows to the liquid recovery channel 19 via the supply port 17a, the pressure chamber 23, and the recovery port 17b C). Such a flow can be recovered from the discharge port 13 and the pressure chamber 23, which are not enriched ink, bubbles, foreign matter, or the like due to evaporation from the discharge port 13 to the liquid recovery channel 19 do. This makes it possible to suppress the thickening of the ink in the pressure chamber 23 and the discharge port 13. The liquid recovered in the liquid recovery channel 19 flows through the opening 21 of the cover 20 and the support 21 in the order of the communication port 51, the individual recovery channel 214 and the common recovery channel 212 of the channel member 210, (See Fig. 9B), and ultimately, is recovered to the supply path of the recording apparatus 1000. In the present embodiment,

That is, the liquid supplied from the recording apparatus main unit to the liquid discharge head 3 is supplied and recovered by the flow of the following procedure. First, the liquid flows from the liquid connecting portion 111 of the liquid supply unit 220 into the liquid discharge head 3. Thereafter, the liquid is supplied to the joint rubber member 100, the communication port 72 provided in the third channel member 70 and the common channel groove 71, the common channel groove 62 provided in the second channel member 60, The port 61 and the individual channel groove 52 and the communication port 51 provided in the first channel member 50. [ Thereafter, the liquid is supplied to the pressure chamber 23 in the order of the liquid supply channel 18 and the supply port 17a provided in the substrate 11. The liquid that has been supplied to the pressure chamber 23 but not discharged from the discharge port 13 is returned to the recovery port 17b and the liquid recovery channel 19 provided in the substrate 11, the opening 21 provided in the cover 20, And the liquid communication port 31 provided in the liquid flow path 30. Thereafter, the liquid flows through the communication port 51 and the individual channel groove 52 provided in the first channel member 50, the communication port 61 and the common channel groove 62 provided in the second channel member 60, The common channel groove 71 and the communication port 72 provided in the channel member 70, and the coupling rubber member 100 in this order. The liquid further flows out of the liquid discharge head 3 from the liquid connection portion 111 provided in the liquid supply unit. In the first circulation path illustrated in FIG. 2, the liquid introduced from the liquid connecting portion 111 passes through the negative pressure control unit 230, and is then supplied to the coupling rubber member 100. 3, the liquid recovered from the pressure chamber 23 passes through the bonding rubber member 100, and thereafter flows from the liquid connection portion 111 through the negative pressure control unit 230 to the liquid discharge head 100. In the second circulation path illustrated in FIG. 3, (3).

Further, all the liquid introduced from one end of the common supply channel 211 of the liquid discharge unit 300 is supplied to the pressure chamber 23 via the individual supply channel 213 as illustrated in FIGS. 2 and 3 It is not. Liquid that flows from the other end of the common supply channel 211 through the liquid supply unit 220 does not enter the individual supply channel 213 at all. Therefore, providing the channel through which the liquid flows without proceeding through the recording element substrate 10 is advantageous in that even when the recording element substrate 10 has microchannels with large flow resistance, as in this application example, So that the backflow of the refrigerant can be suppressed. Therefore, the liquid discharge head according to this application example can suppress the thickening of the liquid in the vicinity of the discharge port and in the pressure chamber, thereby suppressing the discharge deviation from the normal direction and the liquid non-discharge, and consequently, Recording can be performed.

Description of positional relationship between recording element substrates

12 is a plan view showing a partial enlarged view of adjacent portions of the recording element substrate 10 of two adjacent discharge modules. The recording element substrate 10 according to this application example is formed in a parallelogram shape as illustrated in Figs. 10A to 10C. The ejection orifice rows 14a to 14d in which the ejection orifices 13 are arranged on the recording element substrate 10 are arranged to be inclined with respect to the conveyance direction of the recording medium by a certain angle as illustrated in Fig. At least one discharge port of the discharge port row of the adjacent portion of the recording element substrate 10 is thereby overlapped in the transport direction of the recording medium. In Fig. 12, the two discharge ports on line D exist in an overlapping relationship with each other. This layout makes it possible to prevent the black stripes and blank portions of the recorded image from being invisible by the drive control of the overlapping ejection openings even when the position of the recording element substrate 10 deviates from a predetermined position. The configuration illustrated in Fig. 12 can also be used when a plurality of recording element substrates 10 are arranged in a straight line (in-line) instead of a staggered arrangement. Therefore, the black stripes and blank portions in the overlapping portion between the recording element substrates 10 can be processed while suppressing an increase in the length of the liquid discharge head 3 in the transport direction of the recording medium. Although the shape of the main surface of the recording element substrate 10 in accordance with the discharge port row is a parallelogram, this is not restrictive. The configuration of the present disclosure can be suitably applied even when the shape is a rectangle, a trapezoid, or another shape.

Explanation of Variations of Liquid Discharge Head Configuration

A modification of the above-described liquid discharge head configuration will be described with reference to Fig. 32 and Figs. 34A to 36. Fig. The same structure and function as the above-described example will be omitted from the description, and the differences will be mainly described. In this modification, a plurality of liquid connecting portions 111, which are connection portions between the liquid and the outside of the liquid discharge head 3, are arranged in the longitudinal direction of the liquid discharge head 3 as illustrated in Figs. 32, 34A and 34B Are disposed in an integrated manner at one end side. A plurality of negative pressure control units 230 are arranged in an integrated manner on the other end side of the liquid discharge head 3 (Fig. 35). The liquid supply unit 220 included in the liquid discharge head 3 is constituted as a long and thin unit corresponding to the length of the liquid discharge head 3 and includes a channel corresponding to the supplied four color liquid and a filter 221, . The positions of the openings 83 to 86 provided in the liquid discharge unit support member 81 are also different from the above-described liquid discharge head 3 as illustrated in Fig.

36 illustrates a stacked state of the channel members 50, 60, and 70. FIG. A plurality of recording element substrates 10 are arranged in a straight line on the upper surface of the first channel member 50 which is the uppermost layer of the plurality of channel members 50, Two individual supply channels 213 and one individual recovery channel 214 are provided for each liquid color as channels communicating with openings 21 (Figure 19C) formed on the rear side of each recording element substrate 10, exist. Correspondingly, with respect to the opening 21 formed on the cover 20 provided on the rear surface of the recording element substrate 10, two feeding openings 21 for each liquid color and one collecting opening 21 ). The common supply channels 211 and the common collecting channels 212 extending in the longitudinal direction of the liquid discharge head 3 are alternately arranged as illustrated in Fig.

Second example

The configuration of the liquid discharge head 3 and the inkjet recording apparatus 1000 according to the second application example will be described. It is noted that mainly the parts different from the first application example are mainly described, and the same parts as the first application example are omitted from the description.

Explanation of inkjet recording apparatus

20 illustrates an inkjet recording apparatus according to a second application example. The recording apparatus 1000 according to the second application example is different from the first application example in that full color recording is performed on the recording medium by arranging four monochromatic liquid discharge heads 3 respectively corresponding to one of CMYK inks. Although the number of discharge port rows usable per color in the first application example is one row, the number of discharge port rows usable per color in the second application example is 20 rows (Fig. 19A). This makes it possible to perform recording at an extremely high speed by assigning write data to a plurality of ejection opening rows. The reliability can be improved by the discharge port at the corresponding position in the conveying direction of the recording medium of the other row performing the discharging in a complementary manner even when there is a discharge port indicating the ink body discharge, Do. The supply system of the recording apparatus 1000, the buffer tank 1003 and the main tank 1006 (Fig. 2) are connected to the liquid discharge head 3 by fluid connection in the same manner as in the first application example. Each of the liquid discharge heads 3 is also electrically connected to an electric control unit, which transmits power and discharge control signals to the liquid discharge head 3.

Description of the circulation path.

The first circulation path and the second circulation path illustrated in Figs. 2 and 3 can be used as a liquid circulation path between the recording apparatus 1000 and the liquid discharge head 3 in the same manner as the first application example.

Description of the structure of the liquid discharge head

The structure of the liquid discharge head 3 according to the second application example will be described. 13A and 13B are perspective views of the liquid discharge head 3 according to the present application example. The liquid discharge head 3 is an ink jet line recording head having 16 recording element substrates 10 linearly arranged in the longitudinal direction of the liquid discharge head 3 and capable of recording with one color of liquid. The liquid discharge head 3 has a liquid connecting portion 111, an input terminal 91 and a power supply terminal 92 in the same manner as in the first application example. The liquid discharge head 3 according to this application example is different from the first application example in that the input terminal 91 and the power supply terminal 92 are disposed on both sides of the liquid discharge head 3 because the number of discharge port rows is larger. This is intended to reduce the voltage drop and the signal transmission delay occurring in the wiring portion provided on the recording element substrate 10. [

14 is an exploded perspective view of the liquid discharge head 3 illustrating each part or unit constituting the liquid discharge head 3 which is disassembled according to the function. The roles of the unit and the member and the order of the liquid flow through the liquid discharge head are basically the same as those of the first application example, but the functions in which the rigidity of the liquid discharge head is guaranteed are different from each other. The stiffness of the liquid discharge head is mainly ensured by the second channel member 60 included in the liquid discharge unit 300 in the second application example although it is mainly guaranteed by the liquid discharge unit support member 81 in the first application example. In this application example, there is a liquid discharge unit support member 81 connected to both ends of the second channel member 60. This liquid discharge unit 300 is mechanically coupled to the carriage of the recording apparatus 1000, whereby the liquid discharge head 3 is located. The liquid supply unit 220 having the electric wiring substrate 90 and the negative pressure control unit 230 is coupled to the liquid discharge unit support member 81. [ A filter (not shown) is built in the two liquid supply units 220. The two negative pressure control units 230 are set to control the pressure by the high and low negative pressures which are relatively different from each other. When the high-pressure side and low-pressure side negative pressure control units 230 are disposed at the ends of the liquid discharge head 3 as illustrated in Figs. 14A to 15, a common supply channel (not shown) extending in the longitudinal direction of the liquid discharge head 3 (211) and the common collecting channel (212) are opposite to each other. This facilitates the heat exchange between the common supply channel 211 and the common return channel 212 so that the temperature difference between the two common channels can be reduced. This is advantageous in that a temperature difference does not easily occur between the plurality of recording element substrates 10 disposed along the common channel, and therefore, unevenness in recording due to the temperature difference does not easily occur.

The channel member 210 of the liquid discharge unit 300 will be described in detail below. The channel member 210 is a first channel member 50 and a second channel member 60 which are stacked as illustrated in Fig. 14, and the liquid supplied from the liquid supply unit 220 is supplied to the discharge module 200 Distribution. The channel member 210 also functions as a channel member for returning the liquid recirculating from the discharge module 200 to the liquid supply unit 220. The second channel member 60 of the channel member 210 is a channel member in which the common supply channel 211 and the common collecting channel 212 are formed and mainly assumes the stiffness of the liquid discharge head 3 . Thus, the material of the second channel member 60 is sufficiently corrosion resistant to liquids and has high mechanical strength. Examples of suitable materials include stainless steel, titanium (Ti), alumina, and the like.

15A is a view illustrating a side of the first channel member 50 on the side where the discharge module 200 is mounted, and FIG. 15B is a view illustrating a back side from which the second channel member 60 is brought into contact. Unlike the first application example, the first channel member 50 according to the second application example is an arrangement in which a plurality of members corresponding to the discharge module 200 are arranged adjacently. The use of such a divided structure allows a length corresponding to the length of the liquid discharge head to be realized and thus can be suitably used particularly for a liquid discharge head of a comparatively long scale corresponding to, for example, a B2 size and a larger sheet . The communication port 51 of the first channel member 50 communicates with the discharge module 200 by fluid connection as illustrated in Figure 15A and the individual communication port 53 of the first channel member 50 communicates with the discharge module 200 Communicates with the communication port 61 of the second channel member 60 by fluid connection as illustrated in Figs. Figure 15C illustrates a side view of a second channel member 60 in contact with the first channel member 50 and Figure 15D illustrates a cross-section of a middle portion of the second channel member 60 taken in the thickness direction, 15E is a view illustrating a surface of the second channel member 60 to be brought into contact with the liquid supply unit 220. Fig. The function of the channel and the communication port of the second channel member 60 is the same as that of one color in the first application example. One of the common channel grooves 71 of the second channel member 60 is the common supply channel 211 illustrated in FIG. 16, and the other is the common collecting channel 212. Both have a liquid supplied from one end side toward the other end side along the longitudinal direction of the liquid discharge head 3. [ Unlike the case of the first application example, the longitudinal directions of the liquid for the common supply channel 211 and the common recovery channel 212 are opposite to each other.

16 is a perspective view illustrating the connection relationship between the recording element substrate 10 and the channel member 210 with respect to the liquid. A common supply channel 211 and a common collecting channel 212 extending in the longitudinal direction of the liquid discharge head 3 are provided in the channel member 210 as illustrated in Fig. The communication ports 61 of the second channel member 60 are positioned and connected to the respective communication ports 53 of the first channel member 50 so that the communication between the communication channels 61 of the second channel member 60 The liquid supply path from the port 72 to the communication port 51 of the first channel member 50 via the common supply channel 211 is formed. A liquid supply path from the communication port 72 of the second channel member 60 to the communication port 51 of the first channel member 50 via the common recovery channel 212 is also formed in the same manner.

17 is a view illustrating a cross section taken along the line XVII-XVII in Fig. 17 shows how the common supply channel 211 is connected to the discharge module 200 through the communication port 61, the individual communication port 53 and the communication port 51. [ Although omitted in the example of FIG. 17, it can be clearly seen from FIG. 16 that the other cross section will show the individual collection channel 214 connected to the dispensing module 200 via a similar path. A channel is formed on the recording element substrate 10 and the discharge module 200 so as to communicate with the discharge port 13 and a part or all of the supplied liquid is discharged from the discharge port 13 (the pressure chamber 23) ) In the same manner as in the first application example. The common supply channel 211 is connected to the negative pressure producing unit 230 (high pressure side) via the liquid supply unit 220 in the same manner as in the first application example, and the common collecting channel 212 is connected to the negative pressure control unit 230 ) (Low-pressure side). Therefore, a flow occurs due to the differential pressure, and this flow flows from the common supply channel 211 to the ejection port 13 (the pressure recovery chamber 23 through the common recovery channel 212) of the recording element substrate 10.

Description of Discharge Module

Fig. 18A illustrates a perspective view of one discharge module 200, and Fig. 18B is an exploded view thereof. The difference from the first application example is that the plurality of terminals 16 are arranged on both sides (the long side portion of the recording element substrate 10) along the direction of the plurality of ejection orifice rows of the recording element substrate 10 And two flexible printed circuit boards 40 are provided on one recording element substrate 10 and are electrically connected thereto. This is because the number of ejection orifice rows provided on the recording element substrate 10 is 20 columns, which is greatly increased compared to the eight columns in the first application example. The object is to reduce the voltage drop and the signal transmission delay occurring in the wiring portion provided on the recording element substrate 10 by keeping the maximum distance from the terminal 16 to the recording element 15 provided corresponding to the discharge port row short, I will. The liquid communication port 31 of the support member 30 is provided in the recording element substrate 10 and is opened to cover all the ejection orifice rows. The difference is the same as in the first application example.

Description of the structure of the recording element substrate

19A is a schematic view illustrating the surface of the recording element substrate 10 on the side where the discharge port 13 is disposed, and FIG. 19C is a schematic view illustrating the back surface of the element illustrated in FIG. 19A. 19B is a schematic view illustrating the surface of the recording element substrate 10 when the cover 20 provided on the rear surface side of the recording element substrate 10 is removed in Fig. 19C. Fig. The liquid supply channel 18 and the liquid recovery channel 19 are alternately provided on the rear surface of the recording element substrate 10 along the discharge port column direction as illustrated in Fig. 19B. Although the number of the discharge port rows is much larger than that of the first application example, a remarkable difference from the first application example is that the terminals 16 are arranged on both side portions of the recording element substrate 10 along the discharge port row direction as described above It is a point. The basic configuration is the same as that of the first application example. For example, a set of the liquid supply channel 18 and the liquid recovery channel 19 are provided in each discharge port row, and the liquid communication port 31 of the support member 30 An opening 21 is provided in the cover 20 and the like.

Third example

The configuration of the liquid discharge head 3 and the inkjet recording apparatus 1000 according to the third application example will be described. The liquid discharge head 3 according to the third application example is a page-wide head which records in a B2 size recording medium sheet with a single scan. The third application example is similar to the second application example with respect to a plurality of points, and therefore, the difference with respect to the second application example will be mainly described later, and the same parts as the second application example will be omitted from the description.

Explanation of inkjet recording apparatus

37 is a schematic view of an inkjet recording apparatus according to this application example. The recording apparatus 1000 forms an image by ejecting liquid onto the intermediate transferring member (intermediate transferring drum 1007) without directly recording onto the recording medium from the liquid discharge head 3, The recording apparatus 1000 has four monochromatic liquid discharge heads 3 corresponding to the four ink types of CMYK arranged in the arcuate portion along the intermediate transfer drum 1007. [ Therefore, the full-color printing is performed on the intermediate transferring member, the recorded image is dried in an appropriate state on the intermediate transferring member, and then the recording medium 1008 is transferred by the transferring unit 1008 by the sheet conveying roller 1009 2). The sheet conveying system of the second application example mainly has a horizontal conveying path for conveying the cutting sheet, whereas this application example takes a continuous sheet fed from the main roll (not shown) This kind of the drum conveying system can easily convey the sheet in a state in which a specific tension is applied, and therefore, there is little conveyance jamming in performing high-speed recording. Therefore, reliability of the apparatus is improved, The buffer tank 1003 and the main tank 1006 are connected to the liquid discharge head 3 by fluid connection in the same manner as the first and second application examples, Each liquid discharge head 3 is also electrically connected to an electric control unit, which transmits power and discharge control signals to the liquid discharge head 3.

Explanation of the fourth circulation route

Although the first and second circulation paths illustrated in Figs. 2 and 3 between the tank of the recording apparatus 1000 and the liquid discharge head 3 can be applied as the liquid circulation path in the same manner as the second application example, The circulation path illustrated in Fig. The main difference with respect to the second circulation path in Fig. 3 is that a bypass valve 1010 communicating with the channels of the first circulation pump 1001, 1002 and the second circulation pump 1004 is added. The bypass valve 1010 functions to lower the pressure on the upstream side of the bypass valve 1010 due to the valve opening even if the pressure exceeds a predetermined pressure (first function). Further, the bypass valve 1010 functions to open and close the valve at a predetermined timing by a signal from the control board in the recording apparatus main unit (second function).

According to the first function, an excessively large or excessively small pressure can be prevented from being applied to the channel on the downstream side of the first circulating pump 1001, 1002 and on the upstream side of the second circulating pump 1004. For example, when the functions of the first circulation pumps 1001 and 1002 malfunction, an excessive flow rate or pressure can be applied to the liquid discharge head 3. This may cause the liquid to leak from the discharge port 13 of the liquid discharge head 3 or cause the bonded portion in the liquid discharge head 3 to be damaged. However, when a bypass valve is added to the first circulation pumps 1001 and 1002 as in the present application example, opening of the bypass valve 1010 opens the liquid path to the upstream side of the circulation pump, The problem as described above can be suppressed even when it occurs.

Further, due to the second function, when the circulation operation is stopped, all the bypass valves 1010 are controlled by the control signal from the main unit side after the first circulation pumps 1001, 1002 and the second circulation pump 1004 are stopped, As shown in FIG. This allows the high negative pressure (for example, several kPa to several tens kPa) of the downstream portion of the liquid discharge head 3 (between the negative pressure control unit 230 and the second circulation pump 1004) to be released in a short time . When a volumetric pump such as a diaphragm pump is used as the circulating pump, a check valve is usually incorporated in the pump. However, opening of the bypass valve 1010 similarly enables the pressure release from the downstream buffer tank 1003 to be performed on the downstream side of the liquid discharge head 3. Although there is a pressure drop in the channel in the liquid discharge head 3 and in the channel on the upstream side of the liquid discharge head 3 although the pressure release on the downstream side of the liquid discharge head 3 can be performed from the upstream side as well do. Therefore, there is a concern that the pressure discharge takes time, the pressure in the common channel in the liquid discharge head 3 temporarily drops too much, and the meniscus at the discharge port may be destroyed. The opening of the bypass valve 1010 on the upstream side of the liquid discharge head 3 promotes the discharge of pressure on the downstream side of the liquid discharge head 3 and thus the risk of destruction of the meniscus at the discharge port is reduced.

Description of the structure of the liquid discharge head

The structure of the liquid discharge head 3 according to the third application example will be described. Fig. 39A is a perspective view of the liquid discharge head 3 according to the present application example, and Fig. 39B is an exploded perspective view thereof. The liquid discharge head 3 has 36 recording element substrates 10 arranged in a straight line (in-line) in the longitudinal direction of the liquid discharge head 3 and has a line-type (page-wide ) Ink jet recording head. The liquid discharge head 3 is provided with the signal input terminal 91 and the power supply terminal 92 in the same manner as in the second application example and further includes the shield plate 132 for protecting the longitudinal side surface of the head do.

Fig. 39B is an exploded perspective view of the liquid discharge head 3 exemplifying each part or unit constituting the liquid discharge head 3 according to the function (the shield plate 132 is not shown). The roles of the unit and member and the order of liquid flow through the liquid discharge head 3 are basically the same as in the second application example. The third application example differs from the second application example mainly in terms of the shape of the first channel member 50, the position of the negative pressure control unit 230, and the points of the electric wiring substrate 90 divided and arranged in plural. For example, in the case of the liquid discharge head 3 having a length corresponding to the B2 size recording medium, since the amount of electric power used by the liquid discharge head 3 is large, as in the case of the present application example, A substrate 90 is provided. Each of the four electric wiring boards 90 is attached to both sides of the electric wiring board support member 82 attached to the liquid discharge unit support member 81. [

40A is a side view of the liquid discharge head 3 having the liquid discharge unit 300, the liquid supply unit 220 and the negative pressure control unit 230, FIG. 40B is a schematic view illustrating the liquid flow, 40A is a perspective view illustrating a cross-section taken along line XLC-XLC. Portions of the configuration are simplified to facilitate understanding.

The liquid connection portion 111 and the filter 221 are provided in the liquid supply unit 220 and the negative pressure control unit 230 is integrally formed under the liquid supply unit 220. [ This allows the distance in the height direction between the recording element substrate 10 and the negative pressure control unit 230 to be reduced as compared with the second application example. This configuration is also advantageous in that the number of channel connecting portions in the liquid supply unit 220 is reduced, and the number of components and the assembling process can be reduced as well as increased reliability regarding leakage of the recording liquid.

The difference in head between the negative pressure control unit 230 and the surface on which the discharge port is formed is comparatively smaller and therefore the inclination angle of the liquid discharge head 3 with respect to each liquid discharge head 3 as illustrated in Fig. Can be suitably applied to other recording apparatuses. This is because, even when each of the plurality of liquid discharge heads 3 is used at different inclination angles, a reduced head difference enables the negative pressure difference applied to the discharge port of each recording element substrate 10 to be reduced. Reducing the distance from the negative pressure control unit 230 to the recording element substrate 10 also reduces the pressure drop due to fluctuations in the flow of the liquid because the flow resistance is reduced and a more stable negative pressure control can be performed .

40B is a schematic view illustrating the flow of the recording liquid in the liquid discharge head 3; The circuit is the same as the circulation path exemplified in Fig. 38, and Fig. 40B illustrates the liquid flow in each component in the actual liquid discharge head 3. The common supply channel 211 and the common recovery channel 212 are provided in the second channel member 60 whose set is narrow and extend in the longitudinal direction of the liquid discharge head 3. [ The common supply channel 211 and the common collecting channel 212 are configured such that the liquid flows in mutually opposite directions and the filter 221 is disposed on the upstream side of these channels to capture the foreign substance introduced from the connecting portion 111, do. This arrangement in which liquid flows in mutually opposite directions in the common supply channel 211 and the common recovery channel 212 is preferable in that the temperature gradient in the longitudinal direction in the liquid discharge head 3 is reduced. The flow directions of the common supply channel 211 and the common collecting channel 212 are shown to be the same in Fig. 38 to simplify the explanation.

The negative pressure control unit 230 is disposed on the downstream side of each of the common supply channel 211 and the common recovery channel 212. [ The common supply channel 211 has a branch to a plurality of individual supply channels 213 along the path and the common recovery channel 212 has a branch to a plurality of individual recovery channels 214 along the path. An individual supply channel 213 and an individual recovery channel 214 are formed in the plurality of first channel members 50. Each of the individual channels communicates with the opening 21 of the cover 20 provided on the back surface of the recording element substrate 10 (see Fig. 19C)

The negative pressure control unit 230 indicated by H and L in FIG. 40B is a high pressure side H and a low pressure side L unit. Each of the negative pressure control units 230 is a reverse pressure regulating mechanism that is set to control the upstream pressure of the negative pressure control unit 230 at relatively high (H) and low (L) negative pressures. The common supply channel 211 is connected to the negative pressure control unit 230 (high pressure side), and the common recovery channel 212 is connected to the negative pressure control unit 230 (low pressure side). Which creates a differential pressure between the common supply channel 211 and the common recovery channel 212. This differential pressure is generated when the liquid passes from the common supply channel 211 through the individual supply channels 213 and the discharge ports 13 (the pressure chambers 23 and the individual recovery channels 214) in the recording element substrate 10 To flow into the collection channel 212.

40C is a perspective view illustrating a cross-section taken along line XLC-XLC in FIG. 40A. Each ejection module 200 of this application example is configured to include a first channel member 50, a recording element substrate 10, and a flexible printed circuit board 40. This application example does not have the support member 30 (Fig. 18) described in the second application example, and the recording element substrate 10 has the cover 20 which is directly coupled to the first channel member 50. Fig. The common supply channel 211 provided in the second channel member 60 is connected to the second channel member 60 via the individual communication port 53 formed in the lower surface of the first channel member 50 from the communication port 61 provided on the upper surface thereof, And supplies the liquid to the channel 213. Thereafter, the liquid passes through the pressure chamber 23 and is recovered in the common recovery channel 212 via the individual recovery channel 214, the individual communication port 53, and the communication port 61 in that order.

Unlike the arrangement illustrated in the second application example illustrated in Figs. 15A and 15B, the individual communication port 53 on the lower surface (the surface facing the second channel member 60) of the first channel member 50 is formed Is an opening of sufficient size with respect to the communication port (61) formed on the upper surface of the two-channel member (60). According to this configuration, even when there is a positional deviation when the discharging module 200 is mounted on the second channel member 60, the gap between the first channel member 50 and the second channel member 60 can be maintained in a reliable manner Fluid communication is realized, and therefore the yield is improved during head manufacturing, thereby reducing the cost.

First Embodiment

Specific embodiments are described below. Although a description is given of the case of using the liquid discharge head according to the first application example illustrated in Figs. 1 to 12, the liquid discharge head according to another application example can also be used in the same manner.

Description of the flow of liquid in the discharge port

21A to 21C are schematic views for explaining the vicinity of the discharge port of the recording element substrate in detail. Fig. 21A is a plan view from the discharge direction in which liquid is discharged, Fig. 21B is a sectional view taken along the line XXIB-XXIB in Fig. 21A, and Fig. 21C is a perspective view exemplifying a section taken along the line XXIC-XXIC in Fig.

A circulating flow C in which the liquid in the liquid supply channel 18 provided in the substrate 11 flows into the liquid recovery channel 19 through the supply port 17a, the pressure chamber 23 and the recovery port 17b Is formed in the recording element substrate 10 with respect to the discharge port 13 which does not perform the discharging operation as described above. The velocity of the circulating flow C in the pressure chamber 23 is, for example, about 0.1 to 100 mm / s, and the velocity at which the performance of the discharging operation in the state in which the liquid flows has little influence on the droplet landing accuracy or the like. A liquid meniscus, i.e., a discharge port interface 24, which is the interface between the liquid and the atmosphere, is formed in the outlet 13. The discharge port 13 is an opening of the through path 25 formed in the discharge port forming member 12 and is an opening opened on the surface of the discharge port forming member 12 on the side on which the liquid is discharged as illustrated in Fig. In the following description, the through path 25 will be referred to as a "discharge port portion ", and the direction in which liquid is discharged from the discharge port 13 (vertical direction in FIG. 21B) The direction of flow in the chamber 23 (horizontal direction in Figure 21B) will simply be referred to as the "flow direction ".

Now, the dimensions of the pressure chamber 23 and the discharge port portion 25 are defined as follows. The height of the pressure chamber 23 on the upstream side from the portion communicating with the discharge port portion 25 is defined as H, the length of the discharge port portion 25 in the discharge direction is defined as P, W. Examples of these dimensions are 3 to 30 占 퐉 for H, 3 to 30 占 퐉 for P, and 6 to 30 占 퐉 for W. An example of the case where the discharged liquid is an ink will be described later. This ink has a nonvolatile solvent concentration of 30%, a color material concentration of 3%, and a viscosity of 0.002 to 0.003 Pa · s.

22 is an enlarged cross-sectional view of the vicinity of the discharge port 13 and shows the state of the circulating flow C in the discharge port 13, the discharge port portion 25 and the pressure chamber 23 when the circulating flow C is in the steady state . Specifically, the arrows indicate the distance from the supply port 17a to the pressure chambers 23 (23) at a flow rate of 1.26 x 10 < ^-4 > ml / min in the recording element substrate 10 in which H is 14 mu m, P is 5 mu m and W is 12.4 mu m. ≪ / RTI > It should be noted that the length of the arrow in FIG. 22 does not indicate speed.

Although the evaporation of the ink from the ejection port 13 causes a change in the concentration of the color material, the recording element substrate 10 having the above-described dimensions is capable of suppressing such ink stagnation at the ejection opening 13 and the ejection opening portion 25 . That is, the portion of the circulating flow C in the pressure chamber 23 flows inside the discharge port portion 25, reaches the position of the meniscus formed at the discharge port 13 (near the meniscus interface) And returns to the pressure chamber 23 from the discharge port portion 25. Therefore, not only the ink in the discharge port portion 25 already affected by the evaporation but also the ink near the discharge port interface 24, which is particularly large in evaporation or effect, does not wait inside the discharge port portion 25 but flows into the pressure chamber 23 . Here, the characteristic of the circulating flow C is that at least the velocity component (hereinafter referred to as "positive (positive) " component) is determined with respect to the flow direction (direction from left to right in FIG. 21B) in the vicinity of the middle portion (center portion of the discharge port) Quot; velocity component "). The flow mode in which the circulating flow C has a positive velocity component at least in the vicinity of the middle portion of the discharge port interface 24 as illustrated in Fig. 22 is referred to as "flow mode A ". A flow mode having a negative velocity component (from right to left in FIG. 21B) opposite to the positive velocity component of the circulating flow C in the vicinity of the middle portion of the discharge port interface 24 to be described below is referred to as " do.

The inventor of the present invention determines whether or not the circulating flow C of the liquid discharge head is the flow mode A (or the flow mode B) by the above-described dimensions (H, P, W) of the discharge port portion 25 and the pressure chamber 23 . That is, in the liquid discharge head in which the circulating flow C is in the flow mode A, the height H of the pressure chamber 23 on the upstream side, the length P of the discharge port portion 25 in the discharge direction, The length W satisfies the following relationship (see Fig. 21B).

H ^-0.34 x P ^-0.66 x W > 1.7 (1)

Therefore, the flow mode A as illustrated in Fig. 22 is realized in the liquid discharge head which satisfies the relationship of the equation (1), and the flow mode B is realized in the liquid discharge head which does not satisfy the relationship of the equation (1) do. The left side of the equation (1) will be referred to as "decision value J ".

23 is a graph for explaining the relationship between the flow mode and the dimension of the liquid discharge head. The horizontal axis represents the ratio of P to H (P / H), and the vertical axis represents the ratio of W to P (W / P). The thick line T in FIG. 23 is a threshold line satisfying the following relationship.

(2)

(2)

The flow mode A is realized in the liquid discharge head of the portion (shaded region) where the relationship of H, P and W exceeds the threshold line T in Fig. 23, and the flow mode B is realized below the threshold line T. [ That is, the flow mode A is realized in the liquid discharge head satisfying the following relationship.

(3)

(3)

Rearranging equation (3) yields equation (1), so that flow mode A is realized in a liquid discharge head in which the relationship of H, P and W satisfies equation (1). On the other hand, the flow mode B is realized in a liquid discharge head in which the relationship of H, P and W satisfies the following relationship.

H ^-0.34 x P ^-0.66 x W? 1.7 (4)

Now, the liquid discharge head having flow mode B is advantageous in that cracking of the discharge port forming member 12 can be suppressed, because the length P in the longitudinal direction of the discharge port portion 25, that is, This is because the thickness of the discharge port forming member 12 can be made larger. The height H of the pressure chamber 23 can also be increased and this is also advantageous because the pressure difference required to create the circulating flow C can be made smaller.

The relationship described above and the flow in the discharge port portion 25 will be described in detail with reference to Figs. 24 to 25D. 24 is a graph illustrating a result of confirming the flow in the discharge port portion of the liquid discharge head of various shapes. The dot in Fig. 24 represents the liquid discharge head determined to have flow mode A, and the check mark represents the discharge head determined to have flow mode B. 25A to 25D are views illustrating examples of circulating flow of the displayed liquid discharge head by the respective points A to D of FIG.

The liquid discharge head indicated by point A in Fig. 24 has H of 3 占 퐉, P of 9 占 퐉 and W of 12 占 퐉. The decision value J on the left side of the equation (1) is 1.93, which is larger than 1.7. In this case, the actual flow in the discharge port portion 25 is as illustrated in Fig. 25A, which is a flow mode A having a positive velocity component in the vicinity of the middle portion of the discharge port interface 24. The liquid discharge head indicated by point B in Fig. 24 has H of 8 占 퐉, P of 9 占 퐉 and W of 12 占 퐉. The determination value J is 1.39, which is smaller than 1.7. In this case, the actual flow in the discharge port portion 25 is as illustrated in Fig. 25B, which is a flow mode B having a negative velocity component in the vicinity of the middle portion of the discharge port interface 24. The liquid discharge head corresponding to point C in Fig. 24 has H of 6 占 퐉, P of 6 占 퐉 and W of 12 占 퐉. The crystal value J is 2.0, which is greater than 1.7. In this case, the actual flow in the discharge port portion 25 is as illustrated in Fig. 25C, which is a flow mode A having a positive velocity component in the vicinity of the middle portion of the discharge port interface 24. The liquid discharge head indicated by the point D in Fig. 24 has H of 6 占 퐉, P of 6 占 퐉 and W of 6 占 퐉. The determination value J is 1.0, which is less than 1.7. In this case, the actual flow in the discharge port portion 25 is as illustrated in Fig. 25D, which is a flow mode B having a negative velocity component in the vicinity of the middle portion of the discharge port interface 24.

Therefore, the liquid discharge head representing the flow mode A and the liquid discharge head representing the flow mode B can be distinguished by the threshold line T of Fig. 23 as a boundary. That is, the liquid discharge head in which the determination value J of the equation (1) is larger than 1.7 realizes the flow mode A, and the circulating flow C has a positive component at least in the vicinity of the middle portion of the discharge port interface 24 .

It should be noted that the conditions of H, P and W are the dominant influences on whether the circulating flow C in the discharge port portion 25 is flow mode A or flow mode B. As an example, the influence of other conditions such as the flow rate of the circulating flow C, the viscosity of the ink, and the width of the discharge port 13 (the length in the direction perpendicular to the flow direction) is insignificant compared to the conditions of H, P and W. Therefore, the flow velocity of the circulating flow C and the viscosity of the ink can be appropriately set according to the requirements of the liquid discharge head (inkjet recording apparatus) and the use environment conditions. As an example, an ink having a flow rate of the circulating flow (C) in the pressure chamber 23 of 0.1 to 100 mm / s and a viscosity of 0.01 Pa · s may be used. The flow mode A can be maintained if the amount of ink evaporation from the discharge port in the liquid discharge head having the flow mode A increases due to a change in the operating environment or the like and the circulating flow C is appropriately increased. However, on the other hand, in the liquid discharge head in which the dimension is set to realize the flow mode B, the flow mode of the circulating flow C can not be increased by increasing the flow rate. Among the liquid discharge heads in which the flow mode A is realized, a liquid discharge head in which H is 20 占 퐉 or less, P is 20 占 퐉 or less and W is 30 占 퐉 or less is particularly preferable, thereby enabling higher resolution image formation .

Second Embodiment

30 is a view illustrating the flow of ink flowing through the liquid discharge head according to the second embodiment. The liquid discharge head according to this embodiment has a stepped portion at the communicating portion between the discharge port portion 13b and the channel 26 as illustrated in Fig. The portion from the discharge port 13 to the portion where the stepped portion is formed is the discharge port portion 13b and the discharge port portion 13b is formed by the portion (Not shown). Therefore, P, W and H in this embodiment are defined as illustrated in Fig. The flow mode A can also be realized in a liquid discharge head having this shape by setting P, W and H to satisfy equation (3). Therefore, the multi-stepped configuration from the channel toward the discharge port can make the flow resistance from the recording element 15 toward the discharge port 13 relatively small.

Third Embodiment

Figs. 31A and 31B are views illustrating two examples of the shape of the discharge port of the liquid discharge head according to the third embodiment in particular. 31A and 31B are plan views (schematic views) of the discharge port 13 observed from the liquid discharge direction. The discharge port 13 according to the present embodiment is formed so as to form a protrusion 13d extending from the opposite positions toward the center of the discharge port. The protruding portion 13d continuously extends from the outer surface of the discharge port 13 to the inner portion of the discharge port portion 13b. The flow mode A can also be realized in an arrangement with these protrusions by setting H, P and W to satisfy the above-mentioned equation (2).

The ejection orifice of the example illustrated in Fig. 31A has a protrusion 13d that protrudes in the direction intersecting the flow of liquid in the channel 26. Fig. The ejection orifice of the example illustrated in Fig. 31B has a protrusion 13d protruding in the direction along the flow of the ink. The formation of such protrusions in the ejection openings 13 allows the meniscus formed between the protrusions 13d to be held more easily than the meniscus of the other part of the ejection openings so that the liquid droplets of the ink droplet extending from the ejection openings Can be cut at an earlier time. Therefore, the generation of the fine droplet mist generated together with the main droplet can be suppressed.

Description of features common to the first to third embodiments

Explanation of the influence of the relative dielectric constant of the degraded ink

The ink in the discharge port portion 25 and in particular the ink in the vicinity of the discharge port interface 24 has a positive speed component reaching the vicinity of the discharge port interface 24 in the liquid discharge head 3 in the flow mode A And can be moved to the pressure chamber 23 by the circulating flow (C). Therefore, congestion of the ink in the discharge port portion 25 can be suppressed, and an increase in the color material concentration of the ink in the discharge port portion 25 in association with evaporation from the discharge port 13 can be reduced. However, even when the circulating flow C is present in the pressure chamber 23, the circulating flow C can not easily occur near the periphery of the discharge port 13 due to the influence of the viscosity, It is difficult to do.

26A to 26C show a liquid discharge head (J = 1.3, H = 14 μm, P = 11 μm, W = 16 μm) having a flow mode B in FIG. 26A, (J = 3.5, H = 5 占 퐉, P = 5 占 퐉, W = 18 占 퐉) having flow mode A in FIG. 18 [micro] m). 26A to 26C are the procedures in which the circulating flow C is likely to reach the discharge port interface 24. It can be seen from Figs. 26 (b) and 26 (c) that even when the liquid discharge head has the flow mode A, the concentrated ink stagnates in the vicinity of the periphery of the discharge port 13 (the region surrounded by the dotted line as the " Therefore, when the ink has a large amount of solid (for example, 8 wt% or more), the influence of the concentrated ink near the periphery of the discharge port 13 is more easily received, and defect discharge more easily occurs. Solids contained in the ink include emulsions such as pigments, resins, polymers, and the like.

The present inventors have found that decreasing the relative dielectric constant of ink in order to cancel the defect discharge which occurs when using an ink having a large amount of solids causes a receding phenomenon of the pigment of the ink, It was found that the concentration could be suppressed. When the moisture of the ink is evaporated from the discharge port, the pigment having hydrophilicity in the vicinity of the discharge port retreats (moves) to the pressure chamber 23 side (recording element side) containing more water, The concentration of the pigment near the discharge port interface decreases. This will be described with reference to Figs. 27A to 29C.

27A and 27B show a state in which the liquid in the discharge port portion 25 in the state in which the circulating flow C is generated by using the liquid discharge head having the solid amount of 8 wt% or more and the flow mode A (J = 2.3) (Simulation) of the numerical value calculation of the concentration distribution. Fig. 27A illustrates a case where the phenomenon of the retraction of the pigment does not substantially occur, and Fig. 27B illustrates a state of retraction of the pigment. 27C and 27D show a state in which a liquid discharge head having a solid amount of 8 wt% or more and a flow mode A (J = 2.3) is used to discharge the liquid from the discharge port portion 25) of the solvent concentration distribution. Fig. 27 (c) illustrates a case where the phenomenon of the retraction of the pigment does not substantially occur, and Fig. 27 (d) illustrates the state of retraction of the pigment.

Concentration of the ink due to the evaporation of the ink from the discharge port 13 does not occur even if the circulation flow C is generated as illustrated in Fig. 27A, It can not be sufficiently suppressed in the vicinity of the periphery of the pigment, and the pigment is concentrated. As a result, the agglomeration characteristics of the pigment particles between each other are increased, the ink is easily enriched, and in the extreme case, the ink is solidified and the initial discharge defect discharge after the discharge operation is stopped after a certain amount of time (for example, Change) occurs more easily. On the other hand, when the pigment retreats, the pigment is moved back to the pressure chamber 23 side as illustrated in FIG. 27B, and therefore, the discharge port 13 is not formed due to the circulating flow C reaching the discharge port 13, It is not easily stagnated near the periphery of As a result, the ink is not easily enriched and the solidification is suppressed, so that the discharge of the first off-set defect after the rest is not easily occurred.

As illustrated in Figs. 27C and 27D, the concentration of the solvent in the peripheral portion of the discharge port 13 occurs in the same manner regardless of whether or not the pigment retreat occurs. However, it is particularly important to suppress the stagnation of the ink solid near the discharge port 13 from the standpoint of suppressing the influence of the ink enrichment on the discharge, because the effect of the solid such as the pigment is generally larger for the enrichment of the ink .

28 shows a state in which the circulating flow C is formed and the discharging operation is stopped for 10 seconds and thereafter the liquid discharging head having the flow mode A (J = 2.3) Is a graph when two types of ink having different relative dielectric constant (solvent composition) are used. Specifically, the vertical axis is a ratio obtained by taking the average value of the ejection speeds after the 20th ejection after the pause as 1. [ The result drawn is that when the solids in the ink (including emulsions of pigment, resin, polymer and the like) were 15 wt%, the flow rate of the circulating flow C was 10 mm / s (circulation rate), and the head temperature was 55 . The following two types of solvent compositions were used for the inks. Details of the definition of the relative dielectric constant ( _r ) will be described later.

Composition A: 20% by weight of glycerin (Gly), a large relative dielectric constant (? _R = 45)

Composition B: 20% by weight of trimethylolpropane (TMP), a small relative dielectric constant (? _R = 30)

28 shows that the composition B (black dot in FIG. 28) having a relatively low relative dielectric constant has a higher relative dielectric constant than the composition A (circle in FIG. 28) Is relatively small. The reason for this is that the lowering of the relative dielectric constant makes the backward phenomenon of the pigment more remarkable. Therefore, a lower relative dielectric constant is preferable in order to reduce the change in the discharge speed from the first discharge (and then the subsequent discharge) after the rest.

29A to 29C are graphs in which the ejection speeds of three types of inks each having a different relative dielectric constant (solvent composition) are drawn. Specifically, the circulation flow C is formed, the discharge operation is stopped for 10 seconds, and then the discharge rate (the rate at which the average value of the discharge rate after the 20th discharge after the discharge is taken as 1) is plotted against the discharge coefficient value Is a graph when these inks are used in a liquid discharge head having flow mode A (J = 3.5). The result drawn is that when the solids (pigment, polymer, etc.) in the ink are 12 wt% and the flow rates of the circulating flow C are 10 mm / s and 30 mm / s (circulation rate) . The solvent composition of the ink is as shown in the table. FIG. 29A shows the discharge speed of the composition 1, FIG. 29B shows the discharge speed of the composition 2, and FIG. 29C shows the discharge speed of the composition C.

Standard Solvent (wt%) Relative dielectric constant glycerin 2-pyrrolidinone Trimethylol
Propane sum Composition 1 15 5 0 20 45.4 Composition 2 10 5 5 20 40.7 Composition 3 0 5 10 15 33.8

Figs. 29A to 29C show the liquid discharge head of Fig. 26B obtained by using the liquid discharge head of Fig. 26C having flow mode A (J = 3.5) and the circulating flow C having flow mode A (J = 2.3) It can be seen that the outlet surface 24 reaches the outlet surface 24 more easily. However, in the case where the ink has a high solid concentration (12 wt%), as shown in Fig. 29A, even when the circulating flow velocity is high (30 mm / s) The change in the discharge speed of the discharge roller is large. The composition 2 having the specific dielectric constant lower than the composition 1 is preferable because the change in the discharge speed is small overall when the circulating flow velocity is high (30 mm / s) as illustrated in FIG. 29B. On the other hand, the composition 3 having a much lower specific permittivity is much more preferable, as shown in FIG. 29C, even when the circulating flow velocity is low (10 mm / s), since the change in the discharge speed from the initial discharge after the rest is small. Therefore, with respect to the relative dielectric constant? _R ,? _R ? 40.7 is preferable, and? _R ? 33.8 is more preferable. It is also understood from Fig. 28 that? _R ? 30.0 is even more preferable. If the concentration of the ink solids is high, the viscosity tends to increase, and thus the differential pressure required to cause the ink flow to increase the flow rate of the circulating flow C needs to be increased. However, this increase in the differential pressure increases the negative pressure applied to the discharge port 13, which has a negative influence on the discharge characteristic. On the other hand, the slower the flow rate of the circulating flow C is, the more easily the solid of the ink in the discharge port portion 25 becomes stagnant, and the more the defective discharge It occurs easily. However, the change in the discharge speed of the first discharge after the rest is caused by increasing the determination value J in the flow mode A, and also by lowering the relative dielectric constant of the ink so as to cause the retraction of the pigment, Can be suppressed to a lower level.

Explanation of the influence of the relative dielectric constant of the degraded ink

The relative dielectric constant [epsilon] _r of the ink is defined by the following equation, and is used herein as an integer value obtained by rounding off the fractional part.

(5)

(5)

In the above formula (5), n represents the type of the water-soluble organic solvent, ε _n represents the relative dielectric constant of the water-soluble organic solvent represented by _n , r _n represents the relative dielectric constant of the water- And is the physical property value excluding water. In this case, the region to be condensed by the circulating flow (C) can be considered to have little water due to evaporation, so that the water-free water-soluble organic solvent is used as the physical property value of the liquid in the condensation region.

The relative dielectric constant epsilon _n defined by the above-mentioned equation (5) represents the relative dielectric constant of the entire aqueous medium constituted of the water-soluble organic solvent in the ink, specifically, the value calculated as follows. , The values obtained by multiplying the relative dielectric constant (non-dimensional number) inherent to the water-soluble organic solvent by the content (content of the total mass of ink in mass%) in the ink of this component with respect to the component are summed, The content of water in the ink can be found by Karl Fischer titration and the content of water-soluble organic solvent is measured by gas chromatography (GC / MS) MS) or high performance liquid chromatography (LC / MS).

The inks used in the present disclosure may include various types of additives as needed. Examples of such additives include surfactants, pH adjusting agents, defoamers, rust inhibitors, preservatives, antioxidants, reduction inhibitors, evaporation accelerators, chelating agents and the like. The content of such an additive in the ink is very small, and therefore it is not necessary to consider it in the calculation of the relative dielectric constant.

Description of the relationship between the presence / absence of circulating flow in the pressure chamber and the drop in relative dielectric constant of the ink

Even in the configuration in which no circulating flow C is formed in the pressure chamber 23, a poor medium can be used as the ink solvent composition to reduce the relative dielectric constant. However, in the case of a more solid ink such as a pigment or the like, the relative dielectric constant of the ink is difficult to lower even in the configuration in which no circulating flow C is generated in the pressure chamber 23 due to the following two damages.

In a configuration in which no circulating flow C is generated, the pigment is concentrated when the ejection operation is stopped for a predetermined time, so that the optical density OD tends to increase with respect to the originally landed dot after the rest. However, when the relative dielectric constant of the ink is lowered, a retraction phenomenon of the pigment occurs, so that the OD of the first landed dot after the rest is lowered instead. This is the first damage.

Further, in a configuration in which the circulating flow C is not generated, as one measure for solving the solidification due to ink evaporation from the discharge port 13, a good medium having a high relative dielectric constant such as glycerin with good moisture- ) Is used to suppress the solidification due to the pigment concentration. Further, in order to induce the retraction phenomenon of the pigment, it is difficult to cause the pigment concentration to occur by using a blank medium having a low relative dielectric constant, thereby suppressing the solidification. However, excessively promoting the occurrence of the backward phenomenon of the pigment, i.e., excessively promoting the lowering of the relative dielectric constant, causes the retreated pigment to solidify in the pressure chamber 23. This makes it difficult to significantly reduce the relative dielectric constant. This is the second harm.

These two damages can be avoided by creating a circulating flow C in the pressure chamber 23 and it can be added to make the determination value J larger in the flow mode A. [ That is, irrespective of whether or not a backward phenomenon of the pigment occurs, in a state in which the circulating flow C is generated, particularly in a state in which the ink flows through the discharge port portion 25 as the flow mode A, OD does not change easily. Therefore, ink having a lower relative permittivity can be used, and congestion of ink near the periphery of the ejection opening 13 can be suppressed. Irrespective of whether or not a retreating phenomenon of the solidification pigment in the discharge port portion 25 and the pressure chamber 23 occurs, ink having a lower relative dielectric constant can be used. Therefore, the lowering of the relative dielectric constant of the ink is particularly effective in the configuration in which the circulating flow C is generated in the pressure chamber 23. The present disclosure is particularly applicable to flow mode A, but may also apply to flow mode B when a circulating flow C is generated.

Thus, according to the present disclosure, a liquid discharge device and a liquid discharge head capable of high resolution and high quality image formation can be provided.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims (17)

A liquid ejecting apparatus comprising:
A liquid discharge head having a recording element substrate,
Wherein the recording element substrate comprises:
A discharge port configured to discharge liquid,
A pressure chamber having therein a recording element configured to generate energy used to eject liquid;
A liquid supply channel configured to supply liquid to the pressure chamber, and
A liquid recovery channel configured to recover liquid from the pressure chamber;
A liquid discharge head,
And a flow unit configured to cause liquid to flow in the liquid supply channel, the pressure chamber, and the liquid recovery channel in this order,
The relative permittivity? _R of the liquid flowing through the pressure chamber by the flow unit satisfies the relationship of? _R ? 40.7. The method according to claim 1,
The relative dielectric constant? _R of the liquid flowing through the pressure chamber satisfies the relationship of? _R ? 33.8. 3. The method of claim 2,
The relative dielectric constant? _R of the liquid flowing through the pressure chamber satisfies the relationship of? _R ? 30.0. 4. The method according to any one of claims 1 to 3,
A discharge port portion formed between the pressure chamber and the discharge port,
A height (H) of the pressure chamber on the upstream side in the liquid flow direction with respect to the communicating portion with the discharge port portion, a length (P) of the discharge port portion in the liquid discharge direction, ^Wherein a length (W) to a width of the liquid ejection head satisfies a relationship of H ^-0.34 x P- ^0.66 x W > 1.7. 5. The method of claim 4,
Wherein the height (H) is 20 占 퐉 or less, the length (P) is 20 占 퐉 or less, and the length (W) is 30 占 퐉 or less. 4. The method according to any one of claims 1 to 3,
Wherein the flow rate of the liquid flowing through the pressure chamber is 0.1 to 100 mm / s. 4. The method according to any one of claims 1 to 3,
Wherein the solid component of the liquid is at least 8 wt%. A liquid discharge head comprising:
A discharge port configured to discharge liquid,
A recording element configured to generate energy used to eject the liquid;
A pressure chamber having the recording element therein,
A liquid supply channel configured to supply liquid to the pressure chamber; And
And a liquid recovery channel configured to recover liquid from the pressure chamber,
Wherein a liquid having a relative dielectric constant ( _r ) satisfying a relationship of? _R ? 40.7 is circulated through the liquid supply channel, the pressure chamber and the liquid recovery channel in this order. 9. The method of claim 8,
The relative dielectric constant? _{R of the} liquid satisfies the relationship of? _R ? 33.8. 10. The method according to claim 8 or 9,
A discharge port portion formed between the pressure chamber and the discharge port,
A height (H) of the pressure chamber on the upstream side in the liquid flow direction with respect to the communicating portion with the discharge port portion, a length (P) of the discharge port portion in the liquid discharge direction, ^Wherein the length (W) of the liquid discharge head satisfies the relationship of H ^-0.34 x P- ^0.66 x W > 1.7. 11. The method of claim 10,
Wherein the height (H) is 20 占 퐉 or less, the length (P) is 20 占 퐉 or less, and the length (W) is 30 占 퐉 or less. 10. The method according to claim 8 or 9,
Wherein a flow velocity of the liquid flowing through the pressure chamber is 0.1 to 100 mm / s. 10. The method according to claim 8 or 9,
Wherein the solid component of the liquid is at least 8 wt%. 10. The method according to claim 8 or 9,
A plurality of recording element substrates having recording elements; And
Further comprising a channel member for supporting the plurality of recording element substrates and supplying liquid to the plurality of recording element substrates,
Wherein the liquid discharge head is a page-wide liquid discharge head. 15. The method of claim 14,
Wherein the channel member comprises:
A common supply channel configured to supply liquid to the plurality of recording element substrates while extending in an arrangement direction in which the plurality of recording element substrates are arranged,
And a common recovery channel configured to recover liquid from the plurality of recording element substrates while extending in the arrangement direction. 15. The method of claim 14,
And the plurality of recording element substrates are arranged in a straight line. 10. The method according to claim 8 or 9,
Wherein the liquid in the pressure chamber is circulated between the inside of the pressure chamber and the outside of the pressure chamber.

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