JP2017124618A - Liquid ejection apparatus and liquid ejection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably supply liquid to a liquid ejection head through a plurality of supply paths.SOLUTION: Liquid is supplied to a plurality of areas of a liquid ejection head through a plurality of supply paths, and a liquid ejection amount per unit time from the liquid ejection head is controlled so that a liquid flow amount for each of the areas becomes a predetermined amount or less.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a liquid discharge apparatus and a liquid discharge method for discharging a liquid such as ink.

  In recent years, inkjet liquid ejection heads as liquid ejection heads that eject liquid ink have been required to suppress blurring of recording due to insufficient supply of ink in accordance with demands for higher image quality and higher recording speed. Yes. As a cause of blurring of an image, there is a pressure loss in a flow path for supplying ink to an ink ejection port. On the other hand, inks tend to increase in viscosity due to an increase in color materials and resin members in order to improve image quality. In addition, the width of the ink flow path tends to be narrowed as the density of the ejection openings is increased. For these reasons, an increase in pressure loss with increasing recording speed is a major issue.

  Patent Document 1 describes a configuration in which the print flow is pre-read from print data, and the ink flow rate is controlled according to the print duty so that the average flow rate for all the ejection ports becomes a predetermined flow rate. On the other hand, Patent Document 2 describes a configuration in which ink is supplied to a plurality of discharge ports in a liquid discharge head through a plurality of supply paths as the liquid discharge head becomes longer.

JP 2005-280246 A JP 2007-69419 A

  However, in a configuration in which ink is supplied to a plurality of discharge ports in the liquid discharge head through a plurality of supply paths, when ink is supplied as described in Patent Document 1, insufficient supply of ink May occur. That is, as described in Patent Document 1, when the ink flow rate is controlled based on the average flow rate of ink for all the ejection ports, there is a risk that local supply of ink to the liquid ejection head may occur. .

  An object of the present invention is to stably supply liquid to a liquid discharge head through a plurality of supply paths.

  The liquid ejection apparatus according to the present invention is a liquid ejection apparatus having a liquid ejection head having a plurality of ejection openings for ejecting liquid, and supplying liquid to a plurality of regions of the liquid ejection head communicating with the plurality of ejection openings. And a control unit that controls a liquid discharge amount per unit time from the liquid discharge head so that a liquid flow rate for each region is a predetermined amount or less.

  According to the present invention, the liquid flow rate in each of the plurality of regions of the liquid discharge head to which the liquid is supplied through the plurality of supply paths is set to a predetermined amount or less, thereby suppressing local supply of liquid to the liquid discharge head. In addition, the liquid can be supplied stably.

1 is an explanatory diagram of a recording apparatus as a liquid ejection apparatus according to a first embodiment of the present invention. FIG. 2 is a perspective view for explaining a different configuration example of a liquid ejection head in FIG. 1. FIG. 2 is an explanatory diagram of an ink supply system for the liquid ejection head of FIG. 1. FIG. 2 is an explanatory diagram of a recording element substrate in the liquid ejection head of FIG. 1. 3 is a flowchart for explaining a control process of an ink flow rate in the recording apparatus of FIG. 1. FIG. 6 is an explanatory diagram of a relationship between a recording duty and an ink flow rate. It is explanatory drawing of an example of the monitoring area | region of the pressure loss in a liquid discharge head. It is explanatory drawing of the other example of the monitoring area | region of the pressure loss in a liquid discharge head. It is explanatory drawing of the further another example of the monitoring area | region of the pressure loss in a liquid discharge head. It is explanatory drawing of the further another example of the monitoring area | region of the pressure loss in a liquid discharge head. It is explanatory drawing of the recording device as a liquid discharge apparatus of the 2nd Embodiment of this invention. FIG. 12 is an explanatory diagram of an ink supply system for the liquid ejection head of FIG. 11. FIG. 12 is an explanatory diagram of a recording element substrate in the liquid ejection head of FIG. 11. 12 is a flowchart for explaining ink flow rate control processing in the recording apparatus of FIG. 11. It is explanatory drawing of the ink supply system in the recording device as a liquid discharge apparatus of the 3rd Embodiment of this invention. FIG. 16 is an explanatory diagram of a recording element substrate in the liquid ejection head of FIG. 15. FIG. 16 is an explanatory diagram of an example of a pressure loss monitoring region in the liquid ejection head of FIG. 15. It is explanatory drawing of the recording device as a liquid discharge apparatus of the 4th Embodiment of this invention. It is explanatory drawing of the 1st circulation form of the circulation path of the ink applicable to the recording device of FIG. It is explanatory drawing of the 2nd circulation form of the circulation path of the ink applicable to the recording device of FIG. It is explanatory drawing of the circulation amount of the ink in a 1st circulation form and a 2nd circulation form. It is a perspective view of the liquid discharge head in FIG. It is an exploded perspective view of a liquid discharge head. It is a figure which shows the surface and back surface of the 1st, 2nd and 3rd flow-path member in a liquid discharge head. It is an expansion perspective view of the channel formed by joining the 1st, 2nd and 3rd channel members. It is sectional drawing which follows the XXVI-XXVI line | wire of FIG. It is a perspective view of a discharge module. It is explanatory drawing of a recording element board | substrate. FIG. 29 is a perspective view of the recording element substrate taken along a line XXIV-XXIV in FIG. 28. FIG. 4 is an enlarged plan view of adjacent portions in two recording element substrates. It is a perspective view of the liquid discharge head in the 5th Embodiment of this invention. It is an exploded perspective view of a liquid discharge head. It is explanatory drawing of the flow-path member which comprises a liquid discharge head. FIG. 5 is a perspective view for explaining a connection relationship between a recording element substrate and a flow path member in the liquid discharge head. It is sectional drawing which follows the XXXV-XXXV line | wire of FIG. It is explanatory drawing of the discharge module in a liquid discharge head. 2 is a perspective view of a recording element substrate. FIG. It is explanatory drawing of the recording device as a liquid discharge apparatus of the 5th Embodiment of this invention. It is a figure which shows the structure of the liquid discharge head of the 6th Embodiment of this invention. It is a figure which shows the structure of the liquid discharge head of the 6th Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
The liquid ejection apparatus of this embodiment is an application example as an inkjet recording apparatus that records an image using an inkjet liquid ejection head that ejects ink as a liquid. The liquid discharge head of the present invention that discharges liquid such as ink and the liquid discharge device equipped with the liquid discharge head can be applied to devices such as a printer, a copying machine, a facsimile having a communication system, and a word processor having a printer unit. is there. Furthermore, the present invention can be applied to an industrial recording apparatus combined with various processing apparatuses. For example, it can be used for applications such as biochip fabrication, electronic circuit printing, and semiconductor substrate fabrication.

  Each embodiment described below is an appropriate specific example of the present invention, and thus has various technically preferable limitations. However, the application example and the embodiment are not limited to the application example, the embodiment, and other specific methods of the present specification as long as the idea of the present invention is satisfied.

(Configuration of recording device)
FIG. 1A is a schematic perspective view of a main part for explaining the basic configuration of an ink jet recording apparatus 101 to which the present invention can be applied. The recording apparatus 101 of this example is a recording apparatus equipped with a so-called page-wide type liquid discharge head, and includes a transport unit 103 that transports the recording medium 104 in the transport direction of the arrow A, and an ink jet liquid discharge head that can eject ink. (Liquid discharge head) 102. The conveyance unit 103 of this example conveys the recording medium 104 using the conveyance belt 103A. The liquid discharge head 102 is a line-type (page wide type) liquid discharge head that extends in a direction that intersects (in the present example, orthogonal) with the conveyance direction of the recording medium 104, and includes a plurality of ink discharge heads. The discharge ports are arranged along the width direction of the recording medium 104. Ink is supplied to the liquid ejection head 102 from an ink tank (not shown) through an ink supply unit that forms an ink flow path. An image is recorded on the recording medium 104 by ejecting ink from the ejection port of the liquid ejection head 102 based on recording data (ejection data) while continuously conveying the recording medium 104. The recording medium 104 is not limited to a cut sheet, and may be a long roll sheet.

  FIG. 1B is a block diagram for explaining a configuration example of a control system of the recording apparatus 101. The CPU 105 executes control processing of the operation of the recording apparatus 101, data processing, and the like. The ROM 106 stores programs such as those processing procedures, and the RAM 107 is used as a work area for executing these processes. The liquid ejection head 102 includes a plurality of ejection openings, a plurality of ink flow paths communicating with the respective ejection openings, and a plurality of ejection energy generating elements arranged in the respective ink flow paths. Thus, a plurality of nozzles capable of ejecting ink are formed. These nozzles function as recording elements. As the discharge energy generating element, an electrothermal conversion element, a piezoelectric element, or the like can be used. When the electrothermal conversion element is used, the ink in the ink flow path can be foamed by the heat generated by the electrothermal conversion element, and the ink can be ejected from the ejection port using the foaming energy. Ink is ejected from the liquid ejection head 102 when the CPU 105 drives the ejection energy generating element via the head driver 102A based on image data input from the host device 108 or the like. The CPU 105 drives the transport motor 103C that drives the transport unit 103 via the motor driver 103B.

(Configuration of liquid discharge head)
As shown in FIG. 2, the liquid ejection head 102 includes a recording element substrate (liquid ejection substrate) 202 and a support member 201 that supports the recording element substrate 202. The recording element substrate 202 includes an ejection port 203, an ink flow path, And a discharge energy generating element.

  In the liquid discharge head 102 of FIG. 2A, a plurality of recording element substrates 202 are arranged in a staggered manner, and the plurality of discharge ports 203 intersect with the conveyance direction indicated by the arrow A (in this example, orthogonal). It is arranged in the direction to. In the case of this example, the discharge ports 203 are arranged so as to form four discharge port arrays, and these discharge port arrays may discharge different inks, or discharge the same ink. It may be. In the liquid discharge head 102 of FIG. 2B, a plurality of recording element substrates 202 are arranged adjacent to each other. In the liquid discharge head 102 of FIG. 2C, a single recording element substrate 202 is disposed. The configuration of the liquid ejection head 102 is not limited to the examples of FIGS. 2A, 2B, and 2C, and various configurations that are arbitrary can be adopted.

(Configuration of ink supply system)
FIG. 3 is a schematic diagram for explaining a configuration example of a supply system that supplies ink to the liquid ejection head 102.

  The liquid connection head 302 of the liquid discharge head 102 is fluidly connected to the main tank 301 via the common channel 303. The common flow path 303 and the liquid discharge head 102 are connected at the liquid connection portion 302a, and the ink in the main tank 301 is supplied to the liquid discharge head 102. The ink supplied to the liquid discharge head 102 is supplied to the recording element substrate 202 corresponding to the branched flow paths 304 via the branched flow paths 304 branched into a plurality from the common flow path 303.

(Description of configuration of recording element substrate)
4A, 4 </ b> B, and 4 </ b> C are explanatory diagrams of a configuration example of the recording element substrate 202 in the liquid discharge head 102.

  FIG. 4A is a perspective view of the recording element substrate 202 of this example, and an orifice plate 401 is bonded on the substrate 402. The orifice plate 401 is provided with a plurality of discharge ports 203, and these discharge ports 203 form a discharge port array 403. Electronic devices such as ejection energy generating elements, electric circuits, electric wirings, and temperature sensors can be arranged on the surface of the substrate 402 by semiconductor processing. Therefore, as a material of the substrate 402, a flow path is formed by MEMS processing. Materials such as possible semiconductor substrates are desirable. Any material can be used as the material of the orifice plate 401. For example, a resin substrate capable of forming an ejection port by laser processing, an inorganic plate capable of forming an ejection port by dicing, a photosensitive resin material capable of forming an ejection port and a channel by photocuring, and an ejection port and a channel by MEMS processing A semiconductor substrate or the like that can form the substrate can be used.

  4B is an enlarged perspective view of the recording element substrate 202 viewed from the orifice plate 401 side, and FIG. 4C is a cross-sectional view taken along the line IVc-IVc in FIG. 4B. The configuration of the recording element substrate will be described with reference to FIGS. 4B and 4C. A pressure chamber 404 is formed in the space between the substrate 402 and the orifice plate 401. An energy generating element 405 for discharging ink from the discharge port 203 is disposed at a position of the substrate 402 facing the discharge port 203. As the energy generating element 405, an electrothermal conversion element (heater), a piezoelectric element, or the like can be used. The pressure chamber 404 is fluidly connected to the common liquid chamber 407 to form a series of ink flow paths (fluid flow paths). Discharge port arrays 403 are formed in parallel with the common liquid chamber 407 on both sides of the common liquid chamber 407 extending in the vertical direction in FIG. 4B (left and right in FIGS. 4B and 4C). The ink in the common liquid chamber 407 is ejected from the ejection port 203 through the pressure chambers 404 on both sides thereof.

(Ink supply system pressure loss)
In general, when recording an image by ejecting ink from the liquid ejection head 102, the higher the ink viscosity and the higher the ink ejection frequency, the greater the pressure loss in the ink supply system, resulting in insufficient ink supply. Recording failure tends to occur. The reason will be described below.

  The pressure loss ΔP when ink is ejected from the ejection port is obtained by ΔP = viscosity resistance R of the supply flow path × ink flow rate Q. The viscosity resistance R changes depending on the viscosity of the ink, and the pressure loss increases as the ink becomes higher in viscosity. In addition, the fact that the ink supply flow path to the ejection port is narrowed to increase the density of the ejection port is a factor that increases the pressure loss. For this reason, drop formation is disturbed due to the drop of the meniscus (increase in mist, fluctuation in the discharge amount Vd), which may cause recording failure. Therefore, it is considered that the influence of the local pressure loss can be suppressed by calculating the pressure loss in units of the monitoring area. The flow rate Q is determined by the ink ejection frequency (corresponding to the number of ink ejections per unit time) and the number of ejection ports.

  In this embodiment, as shown in FIGS. 6 to 10, the pressure loss for each monitoring region of the recording element substrate corresponding to the parallel branch flow paths is calculated. However, the monitoring area may be in a form other than this embodiment. For example, in a configuration in which ink is supplied to a plurality of recording element substrates 202 from a main common supply flow path in which a circulation flow flows from upstream to downstream, it is downstream of the recording element substrate 202 located upstream. The recording element substrate 202 located on the side has a larger pressure loss. In such a configuration, when ink is ejected from both the upstream and downstream recording element substrates, the downstream recording element substrate 202 is more likely to be insufficiently supplied. In this way, by controlling the ink flow rate (liquid flow rate) in consideration of the effect of pressure loss for each printing element substrate, local ink supply shortage on a plurality of printing element substrates can be alleviated and normal ink can be obtained. Discharging becomes possible. The duty threshold value in the monitoring area is determined by calculating the ink flow rate as will be described later with respect to the arrangement direction of the ejection ports. Further, the recording medium conveyance direction (relative movement direction with respect to the liquid ejection head) can be arbitrarily set by determining the influence of pressure loss from the printed image.

(Ink flow control example)
FIG. 5 is a flowchart for explaining the ink flow rate control process executed by the CPU 105.

  The CPU 105 reads image data from the host device 108 or the like (step S1), then designates an ink flow rate monitoring region (step S2), and then calculates the number of ejection ports in that region (step S3). The monitoring area of the ink flow rate will be described later. The processing of steps S2 and S3 can be executed based on known parameters, and it is not necessary to calculate the number of monitoring areas and the number of ejection ports for each recording operation, and these are stored as design default values at the time of design. You may keep it. For each monitoring area, the average flow rate Q of ink passing through the monitoring area is calculated from the ejection frequency and ejection amount of ink ejected from the monitoring area and the number of ejection ports in the monitoring area (step S4). ). Then, these monitoring areas are regarded as pressure loss portions, and for each monitoring area, the pressure loss ΔP is calculated from the ink viscosity resistance R and the average flow rate Q (step S5), and the pressure loss ΔP is a predetermined value. It is determined whether or not ΔTP is exceeded (step S6). If the pressure loss ΔP does not exceed the predetermined value ΔTP, the recording operation is performed without controlling the ink flow rate (step S7). On the other hand, when the pressure loss ΔP exceeds the predetermined value ΔTP, the ink flow rate is controlled (step S8). That is, the ink discharge frequency is decreased, and the conveyance speed of the recording medium 104 is decreased correspondingly, thereby reducing the ink flow rate passing through the monitoring region. Thereby, the pressure loss ΔP in the monitoring region can be suppressed to a predetermined value ΔTP or less. Thereafter, a recording operation is performed (step S7).

  FIG. 6 is an explanatory diagram of an ink flow rate monitoring region.

  As shown in FIG. 6A, the four recording element substrates 202 in the liquid discharge head 102 are referred to as substrates C1, C2, C3, and C4. The liquid discharge head in the present embodiment is assumed to be a page-wide type having a length corresponding to the width of the recording medium. However, in order to simplify the description, a description will be given of a configuration including four recording element substrates. 6B, 6C, and 6D show a recording pattern 701 recorded on the recording medium 104, and the patterns 701 (C1), 701 (C2), 701 (C3), and 701 (C4) are substrates. Corresponds to C1, C2, C3 and C4. For convenience of explanation, in each of the substrates C1, C2, C3, and C4, the pressure loss becomes a predetermined value ΔTP when the recording duty is 25%, and the pressure loss becomes the predetermined value ΔTP when the average recording duty exceeds 25%. It shall be exceeded. The recording duty corresponds to the amount of ink applied per unit recording area, and when recording a so-called solid image, the recording duty is 100%.

  FIG. 6B is an explanatory diagram when the recording duty of all the substrates C1, C2, C3, and C4 is 25%. In this case, the average recording duty of the entire liquid ejection head 102 is also 25%. Images can be recorded normally. FIG. 6C is an explanatory diagram when the recording duty of the substrates C1, C2 and C3 is 0% and the recording duty of the substrate C4 is 100%. In this case as well, the average recording of the entire liquid discharge head 102 is performed. The duty is 25%. However, since the recording duty of the substrate C4 is 100%, a large amount of ink flows through the branch channel 304 (4) of the substrate C4, and the pressure loss increases. In such a situation, if the ink flow rate is controlled on the condition that the average recording duty of the entire liquid ejection head 102 exceeds 25%, the ink flow rate is not controlled, and the supply of ink to the substrate C4 is insufficient. May occur. Furthermore, if it is attempted to avoid such an insufficient supply of ink, it is necessary to control the ink flow rate when the recording duty exceeds 25% even with one of the substrates C1, C2, C3, and C4. . For this purpose, as shown in FIG. 6D, it is assumed that the recording duty of the substrates C1, C2, and C3 is 0% and the recording duty of the substrate C4 is 25%, and the recording duty of the substrate C4 is 25%. When exceeded, the ink flow must be controlled. In the case of FIG. 6D, the average recording duty of the entire liquid discharge head 102 is 6%, and the average recording duty must be suppressed to 6%, which suppresses the ink flow rate excessively. become. Specifically, the ink ejection frequency and the recording medium conveyance speed must be ¼.

  In the present embodiment, in consideration of such a situation, the ink flow rate is controlled based on the recording duty of each recording element substrate (each liquid ejection substrate) corresponding to the ink branch flow path. In the above example, the ink flow rate is controlled when the recording duty of at least one of the substrates C1, C2, C3 and C4 exceeds 25%.

In the present embodiment, as shown in FIG. 7A, monitoring areas 801 (801 (1), 801 (2), 801 (3), 801 (4)) in units of substrates C1, C2, C3, and C4 are provided. The pressure loss ΔP is calculated for each of these areas. In general, the pressure loss ΔP is expressed by the following equation (1) when the flow resistance is R [Pa · s / m ³ ] and the flow rate is Q [m ³ / s].
ΔP = R × Q (1)

The flow rate Q is expressed by the following equation (2) when the number of discharge ports is n, the discharge amount is Vd [m ³ ], and the discharge frequency fp [Hz].
Q = n × Vd × fop (2)

In this embodiment, the pressure loss ΔP is calculated for each monitoring region 801 (801 (1), 801 (2), 801 (3), 801 (4)). That is, as shown in FIG. 7B, ink is supplied from the four branch channels 304 (304 (1), 304 (2), 304 (3), 304 (4)) branched from the common channel 303. The pressure loss ΔP is calculated for each of the substrates C1, C2, C3, and C4. The flow resistance between the connection part 302a connecting the main tank 301 and the common flow path 303 to the connection part 302b connecting the common flow path 303 and the liquid ejection head 102 is R0, and the flow rate is Q0. First, when the flow resistance of the branch channel 304 (1) is R1 and the flow rate is Q1, the pressure loss ΔP1 of the substrate C1 is expressed by the following equation (3).
ΔP1 = R0 × Q0 + R1 × Q1 (3)

Similarly, the pressure losses ΔP2, ΔP3, ΔP4 of the substrates C2, C3, C4 are expressed by the following equations (4), (5), (6).
ΔP2 = R0 × Q0 + R2 × Q2 (4)
ΔP3 = R0 × Q0 + R3 × Q3 (5)
ΔP4 = R0 × Q0 + R4 × Q4 (6)

  In each of the substrates C1, C2, C3, and C4, the pressure loss becomes a predetermined value ΔTP when the recording duty is 25%, and the pressure loss exceeds the predetermined value ΔTP when the average recording duty exceeds 25%. . When the recording pattern 701 shown in FIG. 6B is recorded, the recording duty of the substrates C1, C2, C3, and C4 does not exceed 25%. Therefore, it is necessary to reduce the ink ejection frequency and the recording medium conveyance speed. There is no. That is, an image can be recorded without reducing the recording speed. When the recording pattern 701 in FIG. 6C is recorded, the recording duty of the substrate C4 exceeds 25%. Therefore, the ink ejection frequency and the recording medium conveyance speed are reduced to reduce the ink flow rate. Thereby, pressure loss is suppressed and occurrence of insufficient supply of ink is suppressed.

  In order to supply ink to the plurality of recording element substrates 202, the form in which the substrate common flow path 303 is branched into the plurality of branch flow paths 304 is only a form in which one branch flow path 304 corresponds to one recording element substrate 202. It is not limited to.

  For example, as shown in FIGS. 8A and 8B, one branch path may correspond to a plurality of recording element substrates 202. 8A and 8B, ink is supplied from the branch path 304 (1) to the substrates C1 and C2, and these substrates C1 and C2 become the monitoring region 802 (1). Further, ink is supplied from the branch path 304 (2) to the substrates C3 and C4, and the substrates C3 and C4 become the monitoring region 802 (2). Further, as shown in FIGS. 9A and 9B, one branch path may correspond to one ejection port array in one printing element substrate 202. 9A and 9B, ink is supplied from the branch path 304 (1) to one ejection port array 403 on the substrate C1, and the ejection port array 403 is in the monitoring region 803 (1). It becomes. Further, ink is supplied from the branch path 304 (2) to the other ejection port array 403 in the substrate C1, and the ejection port array 403 becomes the monitoring region 803 (2). The relationship between the other branch flow paths and the monitoring area in FIGS. 9A and 9B is the same. Further, as shown in FIGS. 10A and 10B, one branch path 304 may correspond to a plurality of ejection ports 203 in one printing element substrate 202. In this case, the same branch path 304 is used. The ejection port 203 to which the ink is supplied from becomes a monitoring area 804. Similarly to the case of FIG. 7, in these cases of FIGS. 8, 9, and 10, the pressure loss is calculated for each monitoring region, and when the pressure loss in any one monitoring region exceeds the threshold value, The ink flow rate can be reduced by lowering the ejection frequency and the conveyance speed of the recording medium.

  As described above, in this embodiment, in the configuration in which ink is supplied to each recording element substrate through the branch flow path branched from the common flow path, the recording element substrate corresponding to the branch flow path is monitored based on the image data. Calculate the pressure loss for each region. When the pressure loss for each monitoring area exceeds a predetermined threshold, the local pressure loss in the liquid ejection head is suppressed by relatedly reducing the ink ejection frequency and the recording medium conveyance speed. can do. That is, the ink can be reliably supplied by reducing the ink discharge amount per unit time from the liquid discharge head. The ejection amount of ink per unit time can be controlled by changing the size of ink droplets in addition to the ejection frequency corresponding to the number of ink ejections per unit time. It is only necessary that the ink discharge amount per unit time can be controlled so that the ink flow rate for each monitoring area is equal to or less than a predetermined amount. The present invention is not limited to the above-described embodiment. For example, in a configuration having a plurality of branch channels branched from a common channel, one monitoring region is provided for each of the plurality of branch channels, or for each branch channel. It is also possible to apply a form in which a plurality of pressure losses are calculated for each monitoring region.

(Second Embodiment)
In the first embodiment, as shown in FIG. 4, the discharge ports 203 are arranged on both sides of the common liquid chamber 407, and ink is supplied to each recording element substrate through a branch flow path branched from the common flow path. The pressure loss was calculated for each monitoring region of the recording element substrate corresponding to the branch flow path. In the present embodiment, in a configuration in which a plurality of openings for supplying ink to the discharge ports are formed in the liquid discharge head, the pressure loss is calculated in units of the openings.

  The recording apparatus of the present embodiment is a serial scanning type recording apparatus as shown in FIG. The liquid discharge head 102 is mounted on the carriage 54 and reciprocated in the main scanning direction indicated by an arrow X together with the carriage 54 by a moving mechanism (not shown). The recording medium 104 is conveyed in the sub-scanning direction indicated by an arrow Y that intersects the main scanning direction (orthogonal in this example) by a conveyance mechanism unit 103 that uses conveyance rollers or a conveyance belt. The conveyance unit 103 in this example is configured to convey the recording medium 104 using a conveyance roller. Recording is performed by alternately repeating the operation of ejecting ink from the liquid ejection head 102 and the transporting operation of transporting the recording medium 104 in the sub-scanning direction while moving the liquid ejection head 102 together with the carriage 54 in the main scanning direction. Images are sequentially recorded on the medium 104.

(Configuration of liquid discharge head)
FIG. 11B is a perspective view of a main part of the liquid ejection head 102 in the present embodiment. In the liquid discharge head 102 of this example, a single recording element substrate 202 is supported by a support member 201. The plurality of ejection ports 203 in the recording element substrate 202 are arranged so as to form ejection port arrays extending in a direction intersecting (or orthogonal in this example) with the main scanning direction. The form of the recording element substrate 202 is not limited to this example. For example, a form in which a plurality of recording element substrates 202 are arranged may be used.

(Configuration of ink supply system)
FIG. 12 is a schematic diagram of an ink supply system for supplying ink to the liquid ejection head 102 in the present embodiment. Ink is supplied from the main tank 301 to the liquid discharge head 102 via the common flow path 303. The common flow path 303 and the main tank 301 are connected by a liquid connection portion 302a, and the common flow path 203 and the liquid discharge head 102 are connected by a liquid connection portion 302b. The ink supplied to the liquid ejection head 102 corresponds to the openings 1401 via the inflow side openings 1401 (1401 (1), 1401 (2), 1401 (3)) branched from the common flow path 303. Supplied to the discharge port. The inflow side opening 1401 will be described later.

(Configuration of recording element substrate)
FIG. 13 is an explanatory diagram of a configuration example of the recording element substrate 202 in the liquid discharge head 102.

  In the recording element substrate 202 of this example, as shown in FIG. 13A, the cover plate 1501 and the substrate 402 are joined, and further, the substrate 402 and the orifice plate 401 are joined. A discharge port 203 is formed. The plurality of discharge ports 203 are arranged to form a discharge port array 403 that intersects (in the present example, orthogonal) with the main scanning direction of the arrow X. Electronic devices such as ejection energy generating elements, electrical circuits, electrical wirings, and temperature sensors can be arranged on the surface of the substrate 402 by a semiconductor process. As a material of the substrate 402, a flow path can be formed by MEMS processing. A semiconductor substrate such as is desirable. Any material can be used as the material of the orifice plate 401. For example, a resin substrate that can form discharge ports by laser processing, an inorganic plate that can form discharge ports by dicing, a photosensitive resin material that can form discharge ports and flow paths by photocuring, or a discharge port and flow paths that can be formed by MEMS processing A semiconductor substrate or the like on which can be formed can be used.

  FIG. 13B is an enlarged perspective view of the recording element substrate 202 as viewed from the orifice plate 401 side. A pressure chamber 404 is formed in the space between the substrate 402 and the orifice plate 401. A discharge energy generating element 405 for discharging ink from the discharge port 203 is disposed at a position of the substrate 402 facing the discharge port 203. As the ejection energy generating element 405, an electrothermal conversion element (heater), a piezoelectric element, or the like can be used. Ink is supplied to the pressure chamber 404 through the vertical supply port 1502. FIG. 13C is a cross-sectional view of the recording element substrate 202 of FIG. 13B taken along line XIII-XIII. The vertical supply port 1502 passes through the substrate 402, and the inflow side back surface flow path 1503 communicating with the vertical supply port 1502 is fluidly connected to the inflow side opening 1401 of the cover plate 1501.

(Ink flow control example)
As shown in FIG. 12, the ink flow rate monitoring region in the present embodiment includes an ejection port 201 corresponding to the opening 1401 (1401 (1), 1401 (2), 1401 (3)) branched from the common flow path 303. A region 805 (805 (1), 805 (2), 805 (3)). Ink is supplied mainly from the opening 1401 corresponding to the monitoring region 805 to the ejection port 201 in the monitoring region 805.

  FIG. 14 is a flowchart for explaining the ink flow rate control process of this embodiment. As in the first embodiment, the pressure loss ΔP for each monitoring region 805 is calculated based on the image data (steps S1 to S5), and it is determined whether or not the pressure loss ΔP exceeds a predetermined value ΔTP ( Step S6). If the pressure loss ΔP does not exceed the predetermined value ΔTP, the recording operation is performed without controlling the ink flow rate (step S7). On the other hand, when the pressure loss ΔP exceeds the predetermined value ΔTP, the ink flow rate is controlled (step S11). In the present embodiment, the ink discharge frequency is decreased, and the moving speed of the carriage 54 is decreased correspondingly, thereby decreasing the ink flow rate passing through the monitoring region. Furthermore, the conveyance speed of the recording medium 104 may be decreased. Thereby, the pressure loss ΔP in the monitoring region can be suppressed to a predetermined value ΔTP or less. Thereafter, a recording operation is performed (step S7).

  The liquid discharge head in the present embodiment is not limited to the configuration shown in FIGS. 12 and 13, and may be, for example, a liquid discharge head including a plurality of recording element substrates as in the first embodiment. The present embodiment can also be applied to such a liquid discharge head.

  As described above, the liquid ejection head according to the present embodiment includes an inflow side back surface flow path 1503 in which a single or a plurality of recording element substrates are provided and communicated with the vertical supply port 1502, an inflow side opening 1401 of the cover plate 1501, Is communicated. In such a liquid discharge head, the pressure loss ΔP for each monitoring region 805 corresponding to the inflow side opening 1401 branched from the common flow path 303 is calculated. When the pressure loss ΔP for each monitoring region 805 exceeds a predetermined threshold value ΔTP, the local pressure loss in the liquid ejection head is suppressed by reducing the ink ejection frequency and the carriage moving speed. Can do. In that case, the conveyance speed of the recording medium may be reduced.

  The present invention is also applied to a configuration for calculating the pressure loss for each monitoring region with the opening position as a boundary, and a configuration for calculating the pressure loss for each monitoring region obtained by further dividing the region with the opening position as a boundary. Is possible.

(Third embodiment)
In the configuration example of the second embodiment, the pressure loss is calculated in units of monitoring areas corresponding to the branch flow paths that supply ink to the liquid ejection head. In the present embodiment, in a so-called circulation configuration in which ink flows from the inflow side opening to the recovery side opening through the ejection port, the pressure loss is calculated in units of monitoring regions corresponding to the inflow side opening and the recovery side opening.

(Configuration of ink supply system)
FIG. 15 is a schematic diagram of an ink supply system for supplying ink to the liquid ejection head 102 in the present embodiment. The ink in the ink tank 1601 is supplied to the liquid ejection head 102 through the ink supply channel 1602. A part of the ink supplied to the liquid discharge head 102 is supplied to the pressure chamber 404, a part of the liquid is discharged from the discharge port 203, and the other ink is recovered to the ink tank 1601 through the ink recovery channel 1607. The While the negative pressure adjusting device 1603 provided in the ink supply flow channel 1602 and the constant flow pump 1606 provided in the ink recovery flow channel 1607, an ink circulation flow is generated between the ink tank 1601 and the liquid ejection head 102, The ink pressure at the ejection port 203 is adjusted. The constant flow pump 1606 and the negative pressure adjusting device 1603 that generate the circulation flow of ink can be provided integrally with the liquid discharge head 102, or can be attached to the outside of the liquid discharge head 102 and liquid via a supply tube or the like. It can even be connected to the ejection head 102. Further, it can be incorporated as a MEMS element such as a micropump inside the recording element substrate.

(Configuration of recording element substrate)
FIG. 16 is an explanatory diagram of a configuration example of the recording element substrate 202 in the liquid ejection head 102. The recording element substrate 202 is configured in the same manner as in the second embodiment.

  FIG. 16B is an enlarged perspective view of the recording element substrate 202 viewed from the orifice plate 401 side. A pressure chamber 404 is formed in a space between the substrate 402 and the orifice plate 401. An ejection energy generating element 405 for ejecting ink from the ejection port 203 is disposed inside the pressure chamber 404 facing the ejection port 203. As the ejection energy generating element 405, an electrothermal conversion element (heater), a piezoelectric element, or the like can be used. Ink is supplied to the pressure chamber 404 through the vertical supply port 1502. FIG. 16C is a cross-sectional view of the recording element substrate 202 of FIG. 16B taken along line XVIc-XVIc. The pressure chamber 404 is fluidly connected by an inflow channel 1604 and a recovery channel 1605, which form a series of channels. Therefore, the ink flows from the inflow channel 1604 through the pressure chamber 404 toward the recovery channel 1605. The vertical supply port 1502 and the vertical recovery port 1701 pass through the substrate 402 and communicate with the inflow channel 1604 and the liquid recovery channel 1605, respectively. Further, an inflow side back surface flow path 1503 communicating with the vertical supply port 1502 and a recovery side back surface flow path 1702 communicating with the vertical recovery port 1701 are respectively an inflow side opening 1401 and a recovery side opening of the cover plate 1501. 1703.

  In the present embodiment, an ink circulation path is formed, and the ejection energy generating element 405 is driven in a state where an ink flow from the inflow channel 1604 to the recovery channel 1605 is generated. Ink is discharged from. In the state where ink flows from the inflow channel 1604 to the recovery channel 1605, the ink ejection operation has little effect on the ink droplet landing accuracy.

(Ink flow control example)
The reason why there is a concern about insufficient supply at the discharge port located at the end of the recording element substrate in the configuration in which ink flows from the inflow side opening to the recovery side opening in the present embodiment will be described below. 28A is a plan view of the recording element substrate 202 shown in FIG. 16A, FIG. 28B is an enlarged view of a portion A in FIG. 28A, and FIG. 28C is FIG. It is a reverse view of the recording element board | substrate 202 of (a). FIG. 29 is a cross-sectional view of the recording element substrate 10 and the cover plate 20 along XXIX-XXIX in FIG. As shown in FIG. 29, ink is circulated from the position of the opening 21 of the cover plate 20 through the liquid supply path 18, the pressure chamber 23, and the liquid recovery path 19. Since the flow path length of the liquid supply path 18 or the liquid recovery path 19 from the opening 21 positioned at the end in the arrangement direction of the discharge ports 13 to the discharge port 13 positioned at the end increases, accordingly, Pressure loss increases. In addition, when ink is ejected from the plurality of ejection ports 13, an increase in the ink flow rate in the liquid supply path 18 or the liquid recovery path 19 is also a factor that increases pressure loss.

  Similarly to the second embodiment, by controlling the ink flow rate based on the pressure loss for each monitoring region as shown in FIG. 14, ink supply shortage due to pressure loss can be suppressed.

  In the present embodiment, as shown in FIG. 17, an inflow side opening 1401 (1401 (1), 1401 (2), 1401 (3)) is branched from an inflow side back surface flow path 1503 that is a common flow path. Further, the collection-side back surface opening 1703 (1703 (1), 1703 (2)) branches off from the collection-side back surface flow path 1702 which is a common flow path. As described with reference to FIG. The ink supplied from the plurality of inflow side openings 1401 formed in the provided cover plate 1501 is supplied to the plurality of pressure chambers 404 through the inflow side back surface flow path 1503 which is a common flow path. The ink is supplied to the recovery side back surface opening 1703 via the recovery side back surface flow path 1702 which is a common flow path.The monitoring area in this embodiment corresponds to each of the inflow side opening 1401 and the recovery side back surface opening 1703. This is a region 806 (806 (1) to 806 (5)) of the nozzle row 403 to be used.

The pressure loss is calculated for each of these monitoring regions 806. At that time, the flow rate Q of ink at each ejection port 203 is taken into consideration, and the flow rate Q is expressed by the following equation (7). Here, the total number of nozzles in the monitoring area is n ′.
Q = (n × Vd × fop) + (n ′ × Q ′) (7)

  However, as described above, the ink circulation flow rate Q 'has little influence on the ink droplet landing accuracy during the ink ejection operation.

  The method for calculating the pressure loss for each monitoring region 806 corresponding to each of the inflow side opening 1401 and the recovery side back surface opening 1703 is the same as that in the first embodiment. The liquid discharge head is not limited to the configuration shown in FIGS. 16 and 17 as long as it can circulate ink. As described above, in the liquid discharge head according to the present embodiment, a single or a plurality of recording element substrates are provided, the inflow side back surface flow path 1503 communicates with the vertical supply port 1502, and the recovery side back surface flow path 1702 is connected with the vertical recovery port 1701. Communicate. The inflow side back surface flow path 1503 and the recovery side back surface flow path 1702 communicate with the inflow side opening 1401 and the recovery side opening 1703 of the cover plate 1501, respectively, thereby forming an ink circulation flow path. In such a liquid discharge head, a pressure loss is calculated for each monitoring region 806 corresponding to the inflow side opening 1401 and the recovery side opening 1703, and the ink flow rate is controlled based on the pressure loss. Thereby, local pressure loss in the liquid discharge head is suppressed, and ink can be normally discharged.

  In addition, the present invention is not limited to the above-described example. For example, the configuration for calculating the pressure loss for each monitoring region with the opening position as a boundary, or for each monitoring region obtained by further dividing the region with the opening position as a boundary. A configuration for calculating the pressure loss may be mentioned. In particular, by making the monitoring area further divided into the area with the opening position as a boundary, more detailed pressure loss can be suppressed.

(Fourth embodiment)
18 to 30 are explanatory views of the fourth embodiment of the present invention, in which the same ink circulation path as that of the third embodiment is formed. Similar to the third embodiment, the local pressure loss in the liquid ejection head can be suppressed by setting the monitoring region and controlling the ink flow rate based on the pressure loss for each monitoring region.

(Description of inkjet recording apparatus)
FIG. 18 is a diagram showing a schematic configuration of a liquid ejection apparatus for ejecting a liquid according to the present invention, in particular, an ink jet recording apparatus (hereinafter also referred to as a recording apparatus) 1000 that performs recording by ejecting ink. The recording apparatus 1000 includes a transport unit 1 that transports the recording medium 2, and a line type (page wide type) liquid ejection head 3 that is disposed substantially orthogonal to the transport direction of the recording medium 2, and includes a plurality of recording media. This is a line type recording apparatus that performs continuous recording in one pass while conveying 2 continuously or intermittently. The liquid discharge head 3 includes a negative pressure control unit 230 that controls the pressure (negative pressure) in the circulation path, a liquid supply unit 220 that is in fluid communication with the negative pressure control unit 230, and ink supply and recovery to the liquid supply unit 220. A liquid connecting portion 111 serving as a mouth and a housing 80 are provided. The recording medium 2 is not limited to cut paper but may be a continuous roll medium. The liquid discharge head 3 is capable of full-color recording with cyan C, magenta M, yellow Y, and black K inks, and includes a liquid supply means, a main tank, and a buffer tank (a supply path for supplying liquid to the liquid discharge head 3). Are connected fluidically. The liquid discharge head 3 is electrically connected to an electric control unit that transmits power and a discharge control signal to the liquid discharge head 3. The liquid path and the electric signal path in the liquid discharge head 3 will be described later.

  The recording apparatus 1000 is an ink jet recording apparatus configured to circulate a liquid such as ink between a tank described later and the liquid ejection head 3. As a form of the circulation, a first circulation form circulated by two circulation pumps (for high pressure and low pressure) arranged on the downstream side of the liquid discharge head 3 and two circulations arranged on the upstream side of the liquid discharge head 3. There is a second circulation form that is circulated by a pump (for high pressure and low pressure). Hereinafter, the first circulation mode and the second circulation mode of the circulation will be described.

(Description of first circulation mode)
FIG. 19 is a schematic diagram showing a first circulation form of the circulation path applied to the recording apparatus 1000 of the present embodiment. The liquid discharge head 3 is fluidly connected to a first circulation pump (high pressure side) 1001, a first circulation pump (low pressure side) 1002, a buffer tank 1003, and the like. In FIG. 19, for the sake of simplicity, only the path through which one of the inks of cyan C, magenta M, yellow Y, and black K flows is shown. A circulation path is provided in the liquid discharge head 3 and the recording apparatus main body.

  In the first circulation mode, the ink in the main tank 1006 is supplied to the buffer tank 1003 by the replenishment pump 1005, and then to the liquid supply unit 220 of the liquid discharge head 3 through the liquid connection portion 111 by the second circulation pump 1004. Supplied. Thereafter, the ink adjusted to two different negative pressures (high pressure and low pressure) by the negative pressure control unit 230 connected to the liquid supply unit 220 circulates in two flow paths on the high pressure side and the low pressure side. The ink in the liquid discharge head 3 circulates in the liquid discharge head by the action of the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002, and the liquid discharge head 3 is connected via the liquid connection portion 111. And is returned to the buffer tank 1003.

  A buffer tank 1003, which is a sub tank, is connected to the main tank 1006, has an air communication port (not shown) that communicates the inside and outside of the tank, and can collect bubbles in the ink. A replenishment pump 1005 is provided between the buffer tank 1003 and the main tank 1006. The replenishment pump 1005 transports ink consumed by ejecting (discharging) ink from the ejection port of the liquid ejection head 3 from the main tank 1006 to the buffer tank 1003, such as recording by ink ejection and recovery of suction.

  The two first circulation pumps 1001 and 1002 draw liquid from the liquid connection portion 111 of the liquid discharge head 3 and flow it to the buffer tank 1003. As the first circulation pump, a positive displacement pump having a quantitative liquid feeding capacity is preferable. Specific examples include a tube pump, a gear pump, a diaphragm pump, and a syringe pump. For example, a general constant flow valve or a relief valve may be arranged at the pump outlet to ensure a constant flow rate. When the liquid discharge head 3 is driven, the first circulation pump (high-pressure side) 1001 and the first circulation pump (low-pressure side) 1002 are operated, so that the ink in the common supply path 211 and the common recovery path 212 has a predetermined flow rate, respectively. Flows. By flowing ink in this way, the temperature of the liquid discharge head 3 during recording is maintained at an optimum temperature. The predetermined flow rate at the time of driving the liquid discharge head 3 is preferably set to be equal to or higher than a flow rate that can be maintained so that the temperature difference between the recording element substrates 10 in the liquid discharge head 3 does not affect the recording image quality. However, if the flow rate is set too high, the negative pressure difference is increased in each recording element substrate 10 due to the pressure loss of the flow path in the liquid discharge unit 300, resulting in uneven density of the image. Therefore, it is preferable to set the flow rate in consideration of the temperature difference and the negative pressure difference between the recording element substrates 10.

  The negative pressure control unit 230 is provided in a path between the second circulation pump 1004 and the liquid discharge unit 300. The negative pressure control unit 230 controls the pressure downstream of the negative pressure control unit 230 (that is, the liquid discharge unit 300 side) even when the ink flow rate in the circulation system fluctuates due to a difference in the discharge amount per unit area. It operates to maintain a preset constant pressure. As the two pressure adjusting mechanisms constituting the negative pressure control unit 230, any pressure control mechanism can be used as long as the pressure downstream of the negative pressure control unit 230 can be controlled with a fluctuation within a certain range around a desired set pressure. Such a mechanism may be used. As an example, a mechanism similar to a so-called “pressure reduction regulator” can be employed. In the circulation channel in the present embodiment, the second circulation pump 1004 pressurizes the upstream side of the negative pressure control unit 230 through the liquid supply unit 220. In this way, the influence of the water head pressure on the liquid discharge head 3 of the buffer tank 1003 can be suppressed, so that the layout flexibility of the buffer tank 1003 in the recording apparatus 1000 can be expanded.

  The second circulation pump 1004 may be any pump that has a lift pressure that is equal to or higher than a certain pressure in the range of the ink circulation flow rate that is used when the liquid discharge head 3 is driven, and a turbo pump or a positive displacement pump can be used. Specifically, a diaphragm pump or the like is applicable. Further, instead of the second circulation pump 1004, for example, a water head tank arranged with a certain water head difference with respect to the negative pressure control unit 230 can be applied. As shown in FIG. 19, the negative pressure control unit 230 includes two pressure adjustment mechanisms each set with a different control pressure. Of the two negative pressure adjustment mechanisms, the relatively high pressure setting side (denoted as H in FIG. 19) and the relatively low pressure side (denoted as L in FIG. 19) pass through the liquid supply unit 220, respectively. Thus, the common supply path 211 and the common recovery flow path 212 in the liquid discharge unit 300 are connected. The liquid discharge unit 300 is provided with a common supply path 211, a common recovery path 212, and individual paths 215 (individual supply paths 213, individual recovery paths 214) communicating with the respective recording element substrates. A pressure adjustment mechanism H is connected to the common supply flow path 211, and a pressure adjustment mechanism L is connected to the common recovery flow path 212, and a differential pressure is generated between the two common flow paths. Since the individual supply channel 213 and the individual recovery channel 214 communicate with the common supply channel 211 and the common recovery channel 212, a part of the liquid flows from the common supply channel 211 to the internal channel of the recording element substrate 10. And flows to the common recovery channel 212 (arrow in FIG. 19).

  In this way, in the liquid ejection unit 300, a part of the liquid passes through each recording element substrate 10 while flowing the liquid so as to pass through the common supply flow path 211 and the common recovery flow path 212. Flow occurs. Therefore, the heat generated in each recording element substrate 10 can be recovered to the outside of the recording element substrate 10 by the ink flowing through the common supply channel 211 and the common recovery channel 212. Further, with such a configuration, when recording is performed by the liquid ejection head 3, it is possible to cause ink to flow even in ejection ports and pressure chambers where ejection is not performed. As a result, the viscosity of the ink that has increased in viscosity within the ejection port is reduced, thereby suppressing the increase in the viscosity of the ink. Further, the thickened ink and the foreign matter in the ink can be collected into the common collection channel 212. For this reason, the liquid discharge head 3 of the present embodiment can perform high-speed and high-quality recording.

(Description of second circulation mode)
FIG. 20 is a schematic diagram illustrating a second circulation form that is a circulation form different from the first circulation form described above, among circulation paths applied to the recording apparatus of the present embodiment. The main difference from the first circulation mode described above is that both of the two pressure adjustment mechanisms constituting the negative pressure control unit 230 are configured so that the pressure upstream of the negative pressure control unit 230 is centered on a desired set pressure. It is a point to control by fluctuation within a certain range. Further, the difference from the first circulation mode is that the second circulation pump 1004 acts as a negative pressure source for reducing the pressure downstream of the negative pressure control unit 230. Further, a first circulation pump (high pressure side) 1001 and a first circulation pump (low pressure side) 1002 are arranged on the upstream side of the liquid discharge head 3, and a negative pressure control unit 230 is arranged on the downstream side of the liquid discharge head 3. This is also different.

  In the second circulation mode, the ink in the main tank 1006 is supplied to the buffer tank 1003 by the replenishment pump 1005. Thereafter, the ink is divided into two flow paths, and circulates in the two flow paths on the high pressure side and the low pressure side by the action of the negative pressure control unit 230 provided in the liquid ejection head 3. The ink divided into the two flow paths on the high pressure side and the low pressure side passes through the liquid connection portion 111 to the liquid discharge head 3 by the action of the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002. And supplied to the liquid discharge head 3. Thereafter, the ink circulated in the liquid discharge head by the action of the first circulation pump (high-pressure side) 1001 and the first circulation pump (low-pressure side) 1002 passes through the negative pressure control unit 230 and passes through the liquid connection portion 111. Collected from the ejection head 3. The collected ink is returned to the buffer tank 1003 by the second circulation pump 1004.

  The negative pressure control unit 230 in the second circulation mode has a pressure fluctuation on the upstream side of the negative pressure control unit 230 (that is, the liquid discharge unit 300 side) even if there is a fluctuation in flow rate caused by a change in the discharge amount per unit area. Is stabilized within a certain range around a preset pressure. In the circulation channel of the present embodiment, the second circulation pump 1004 depressurizes the downstream side of the negative pressure control unit 230 via the liquid supply unit 220. In this way, since the influence of the water head pressure of the buffer tank 1003 on the liquid discharge head 3 can be suppressed, the selection range of the layout of the buffer tank 1003 in the recording apparatus 1000 can be widened. Instead of the second circulation pump 1004, for example, a water head tank arranged with a predetermined water head difference with respect to the negative pressure control unit 230 can be applied. In the second circulation mode, similarly to the first circulation mode, the negative pressure control unit 230 includes two pressure adjustment mechanisms each having a different control pressure. Of the two negative pressure adjustment mechanisms, the high pressure setting side (denoted as H in FIG. 20) and the low pressure setting side (denoted as L in FIG. 20) each pass through the liquid supply unit 220 and then the liquid discharge unit. 300 is connected to a common supply path 211 and a common recovery flow path 212 in 300. By making the pressure of the common supply flow path 211 relatively higher than the pressure of the common recovery flow path 212 by two negative pressure adjusting mechanisms, the individual flow paths 211 to the individual flow paths 213 and the inside of each recording element substrate 10 An ink flow that flows to the common recovery channel 212 via the channel is generated.

  In such a second circulation mode, an ink flow state similar to that in the first circulation mode can be obtained in the liquid ejection unit 300, but there are two advantages different from those in the first circulation mode. The first advantage is that, in the second circulation mode, the negative pressure control unit 230 is disposed downstream of the liquid discharge head 3, so that dust and foreign matters generated from the negative pressure control unit 230 flow into the liquid discharge head 3. There is little concern to do. The second advantage is that in the second circulation mode, the maximum required flow rate supplied from the buffer tank 1003 to the liquid ejection head 3 is smaller than in the first circulation mode. The reason is as follows.

  The total of the flow rates in the common supply channel 211 and the common recovery channel 212 when circulating during recording standby is defined as a flow rate A. The value of the flow rate A is defined as the minimum flow rate required to bring the temperature difference in the liquid discharge unit 300 within a desired range when adjusting the temperature of the liquid discharge head 3 during recording standby. Further, a discharge flow rate when ink is discharged from all the discharge ports of the liquid discharge unit 300 (at the time of full discharge) is defined as a flow rate F (discharge amount per discharge port × discharge frequency per unit time × number of discharge ports).

  FIG. 21 is a schematic diagram illustrating the difference in the amount of ink flowing into the liquid ejection head 3 between the first circulation mode and the second circulation mode. FIG. 21A shows a standby time in the first circulation mode, and FIG. 21B shows a full discharge time in the first circulation mode. FIGS. 21 (c) to 21 (f) show the second circulation form. FIGS. 21 (c) and 21 (d) show the case where the flow rate F <the flow rate A, and FIGS. This is the case where the flow rate F> the flow rate A, and shows the flow rates during standby and full discharge, respectively. When the flow rate F is equal to the flow rate A, the flow rate may be any of FIGS. 21 (c) and 21 (d) or FIGS.

  In the case of the first circulation mode in which the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002 having a quantitative liquid feeding capacity are arranged on the downstream side of the liquid discharge head 3 (FIG. 21 ( a), (b)), and the total set flow rate of these pumps 1001, 1002 is A. With this flow rate A, the temperature in the liquid discharge unit 300 during standby can be managed. When total discharge is performed by the liquid discharge head 3, the total set flow rate of the pump 1001 and the pump 1002 remains at the flow rate A. However, the negative pressure generated by the discharge from the liquid discharge head 3 acts, and the maximum flow rate supplied to the liquid discharge head 3 is the sum of the set flow rate A and the amount consumed by the total discharge (flow rate F). Therefore, the maximum value of the supply amount to the liquid ejection head 3 is the flow rate A + the flow rate F because the flow rate F is added to the flow rate A (FIG. 21B).

  On the other hand, in the case of the second circulation mode in which the first circulation pump 1001 and the first circulation pump 1002 are arranged on the upstream side of the liquid discharge head 3 (FIG. 21 (c) to FIG. 21 (f)), recording standby The supply amount to the liquid discharge head 3 that is sometimes required is the flow rate A as in the first circulation mode. Accordingly, in the second circulation mode in which the first circulation pump 1001 and the first circulation pump 1002 are arranged on the upstream side of the liquid discharge head 3, the flow rate A is higher than the flow rate F (FIG. 21 (c), (d )), The flow rate A is sufficient for the supply amount to the liquid discharge head 3 even during full discharge. At that time, the recovery flow rate from the liquid discharge head 3 is flow rate A−flow rate F (FIG. 21D). However, when the flow rate F is higher than the flow rate A (FIGS. 21E and 21F), the flow rate becomes insufficient if the supply flow rate to the liquid ejection head 3 is the flow rate A at the time of full ejection. Therefore, when the flow rate F is higher than the flow rate A, the supply amount to the liquid ejection head 3 needs to be the flow rate F. At that time, if the full discharge is performed, the flow rate F is consumed in the liquid discharge head 3, so that the recovery flow rate from the liquid discharge head 3 is hardly recovered (FIG. 21 (f)). In the case where the flow rate F is higher than the flow rate A and the discharge is performed but not the full discharge, the amount obtained by subtracting the amount consumed by the discharge from the flow rate F is collected from the liquid discharge head 3.

  As described above, in the case of the second circulation mode, the total value of the set flow rates of the first circulation pump 1001 and the first circulation pump 1002, that is, the maximum value of the necessary supply flow rate is the larger value of the flow rate A or the flow rate F. . Therefore, as long as the liquid discharge unit 300 having the same configuration is used, the maximum value of the required supply amount (flow rate A or flow rate F) in the second circulation mode is the maximum value of the required supply flow rate (flow rate A + flow rate) in the first circulation mode. Smaller than F).

  Therefore, in the case of the second circulation mode, the degree of freedom of the applicable circulation pump is increased. For example, a low-cost circulation pump with a simple configuration is used, or a load of a cooler (not shown) installed in the main body side path is reduced. There is an advantage that the cost of the recording apparatus can be reduced. This advantage increases as the line head has a relatively large value of the flow rate A or the flow rate F. Among line heads, a line head having a long length in the longitudinal direction is more beneficial.

  On the other hand, however, the first circulation mode is advantageous over the second circulation mode. That is, in the second circulation mode, the flow rate that flows through the liquid ejection unit 300 during recording standby is maximum, so that the smaller the amount of ejection per unit area (hereinafter also referred to as a low-duty image), A high negative pressure is applied. For this reason, when the flow path width is narrow and the negative pressure is high, a high negative pressure is applied to the discharge port in a low-duty image in which unevenness is easily visible, so that many so-called satellite droplets are discharged along with the main ink droplets. It may occur and the recording quality may deteriorate.

  On the other hand, in the case of the first circulation mode, since a high negative pressure is applied to the discharge port when an image with a large discharge amount per unit area (hereinafter also referred to as a high duty image) is formed, satellite droplets are temporarily generated. Even if it is difficult to see, there is an advantage that the influence on the image is small. These two circulation modes can be selected in light of the specifications of the liquid discharge head and the recording apparatus main body (discharge flow rate F, minimum circulation flow rate A, and in-head flow path resistance).

(Description of liquid discharge head configuration)
The configuration of the liquid ejection head 3 according to this embodiment will be described. FIG. 22A and FIG. 22B are perspective views showing the liquid discharge head 3 according to this embodiment. In the liquid discharge head 3, 15 recording element substrates 10 capable of discharging inks of four colors of cyan C / magenta M / yellow Y / black K are arranged in a straight line (arranged inline) by one recording element substrate 310. This is a line type liquid discharge head. As shown in FIG. 22A, the liquid ejection head 3 includes each recording element substrate 310, a signal input terminal 91 and a power supply terminal 92 electrically connected via the flexible wiring substrate 40 and the electric wiring substrate 90. Prepare. The signal input terminal 91 and the power supply terminal 92 are electrically connected to the control unit of the recording apparatus 1000 and supply the ejection drive signal and the power necessary for ejection to the recording element substrate 310, respectively. By consolidating the wiring by the electric circuit in the electric wiring board 90, the number of signal output terminals 91 and power supply terminals 92 can be reduced as compared with the number of recording element boards 310. This reduces the number of electrical connections that need to be removed when the liquid ejection head 3 is assembled to the recording apparatus 1000 or when the liquid ejection head is replaced. As shown in FIG. 22B, the liquid connection portions 111 provided at both ends of the liquid ejection head 3 are connected to the liquid supply system of the recording apparatus 1000. Thus, cyan C / magenta M / yellow Y / black K four color inks are supplied from the supply system of the recording apparatus 1000 to the liquid discharge head 3, and ink that has passed through the liquid discharge head 3 is supplied to the supply system of the recording apparatus 1000. It has come to be collected. As described above, the ink of each color can be circulated through the path of the recording apparatus 1000 and the path of the liquid discharge head 3.

  FIG. 23 is an exploded perspective view showing each component or unit constituting the liquid discharge head 3. The liquid discharge unit 300, the liquid supply unit 220, and the electric wiring substrate 90 are attached to the housing 80. The liquid supply unit 220 is provided with a liquid connection portion 111 (see FIG. 20), and each color communicated with each opening of the liquid connection portion 111 in the liquid supply unit 220 in order to remove foreign matters in the supplied ink. Another filter 221 (see FIGS. 19 and 20) is provided. The two liquid supply units 220 are each provided with filters 221 for two colors. In the first circulation form as shown in FIG. 19, the liquid that has passed through the filter 221 is supplied to the negative pressure control unit 230 disposed on the liquid supply unit 220 corresponding to each color. The negative pressure control unit 230 is a unit composed of a pressure regulating valve for each color, and the inside of the supply system of the recording apparatus 1000 (liquid is generated by the action of a valve and a spring member provided in each of the negative pressure control units 230 The pressure loss change in the supply system upstream of the discharge head 3) is greatly attenuated. Thus, the negative pressure control unit 230 can stabilize the negative pressure change on the downstream side (liquid ejection unit 300 side) from the negative pressure control unit within a certain range. In the negative pressure control unit 230 for each color, two pressure regulating valves for each color are incorporated as described in FIG. The two pressure regulating valves are set to different control pressures, the high pressure side is the common supply channel 211 (see FIG. 19) in the liquid discharge unit 300, and the low pressure side is the common recovery channel 212 (see FIG. 19) and the liquid supply unit. Communicate via 220.

  The casing 80 includes a liquid discharge unit support part 81 and an electric wiring board support part 82, supports the liquid discharge unit 300 and the electric wiring board 90, and ensures the rigidity of the liquid discharge head 3. The electric wiring board support part 82 is for supporting the electric wiring board 90 and is fixed to the liquid discharge unit support part 81 by screws. The liquid discharge unit support portion 81 has a role of correcting the warp and deformation of the liquid discharge unit 300 and ensuring the relative positional accuracy of the plurality of recording element substrates 10, thereby suppressing streaks and unevenness in the recorded matter. . Therefore, the liquid discharge unit support portion 81 preferably has sufficient rigidity, and a metal material such as SUS or aluminum, or a ceramic such as alumina is preferable as the material. The liquid discharge unit support portion 81 is provided with openings 83 and 84 into which the joint rubber 100 is inserted. The liquid supplied from the liquid supply unit 220 is guided to the third flow path member 70 constituting the liquid discharge unit 300 via the joint rubber.

  The liquid discharge unit 300 includes a plurality of discharge modules 200 and a flow path member 210, and a cover member 130 is attached to the surface of the liquid discharge unit 300 on the recording medium side. Here, the cover member 130 is a member having a frame-like surface provided with a long opening 131 as shown in FIG. 23. From the opening 131, the recording element substrate 10 included in the discharge module 200 and the sealing member 130 are sealed. The stopper 110 (see FIG. 27 described later) is exposed. The frame portion around the opening 131 functions as a contact surface of a cap member that caps the liquid ejection head 3 during recording standby. For this reason, a closed space is formed at the time of capping by applying an adhesive, a sealing material, a filler, or the like along the periphery of the opening 131 and filling the irregularities and gaps on the discharge port surface of the liquid discharge unit 300. It is preferable to do so.

  Next, the configuration of the flow path member 210 included in the liquid discharge unit 300 will be described. As shown in FIG. 23, the flow path member 210 is formed by laminating the first flow path member 50, the second flow path member 60, and the third flow path member 70, and the liquid supplied from the liquid supply unit 220 is removed. Distribute to each discharge module 200. The flow path member 210 is a flow path member for returning the liquid circulating from the discharge module 200 to the liquid supply unit 220. The flow path member 210 is fixed to the liquid discharge unit support portion 81 with screws, thereby suppressing warpage and deformation of the flow path member 210.

  FIGS. 24A to 24F are views showing the front surface and the back surface of each flow path member of the first to third flow path members. 24A shows the surface of the first flow path member 50 on the side where the discharge module 200 is mounted, and FIG. 24F shows the liquid discharge unit support portion 81 of the third flow path member 70. The surface on the abutting side is shown. The first flow path member 50 and the second flow path member 60 are joined so that FIG. 24B and FIG. 24C, which are contact surfaces of the respective flow path members, face each other. The member and the third flow path member are joined so that FIG. 24D and FIG. 7E, which are contact surfaces of the respective flow path members, face each other. By joining the second flow path member 60 and the third flow path member 70, the eight flow paths extending in the longitudinal direction of the flow path member from the common flow path grooves 62 and 71 formed in each flow path member. Common flow paths (211a, 211b, 211c, 211d, 212a, 212b, 212c, 212d) are formed. As a result, a set of the common supply channel 211 and the common recovery channel 212 is formed in the channel member 210 for each color. Ink is supplied from the common supply flow path 211 to the liquid discharge head 3, and the ink supplied to the liquid discharge head 3 is recovered by the common recovery flow path 212. The communication port 72 (see FIG. 24F) of the third flow path member 70 communicates with each hole of the joint rubber 100 and is in fluid communication with the liquid supply unit 220 (see FIG. 23). On the bottom surface of the common channel groove 62 of the second channel member 60, there are communication ports 61 (a communication port 61-1 communicating with the common supply channel 211 and a communication port 61-2 communicating with the common recovery channel 212). A plurality are formed and communicate with one end of the individual flow channel 52 of the first flow channel member 50. A communication port 51 is formed at the other end of the individual flow channel 52 of the first flow channel member 50, and is in fluid communication with the plurality of discharge modules 200 via the communication port 51. The individual flow channel 52 enables the flow channels to be concentrated on the center side of the flow channel member.

  The first to third flow path members are preferably made of a material having corrosion resistance to the liquid and a low linear expansion coefficient. As a material, for example, a composite material (aluminum, LCP (liquid crystal polymer), PPS (polyphenyl sulfide) or PSF (polysulfone or modified PPE (polyphenylene ether)) as a base material and an inorganic filler such as silica fine particles or fibers added ( Resin material) can be suitably used. As a method of forming the flow path member 210, three flow path members may be laminated and bonded to each other. When a resin composite resin material is selected as the material, a joining method by welding may be used.

  FIG. 25 shows the α portion of FIG. 24A, and the flow path in the flow path member 210 formed by joining the first to third flow path members is the first flow path member 50. It is the perspective view which expanded and showed a part from the surface side in which the discharge module 200 is mounted. The common supply flow path 211 and the common recovery flow path 212 are alternately arranged from the flow paths at both ends. Here, the connection relation of each flow path in the flow path member 210 will be described.

  The channel member 210 is provided with a common supply channel 211 (211a, 211b, 211c, 211d) and a common recovery channel 212 (212a, 212b, 212c, 212d) extending in the longitudinal direction of the liquid ejection head 3 for each color. It has been. A plurality of individual supply channels (213 a, 213 b, 213 c, and 213 d) formed by the individual channel grooves 52 are connected to the common supply channel 211 of each color via the communication port 61. In addition, a plurality of individual recovery channels (214a, 214b, 214c, 214d) formed by the individual channel grooves 52 are connected to the common recovery channel 212 of each color via the communication port 61. With such a flow path configuration, it is possible to collect ink from each common supply flow path 211 via the individual supply flow path 213 to the recording element substrate 10 located at the center of the flow path member. Ink can be recovered from the recording element substrate 10 to each common recovery channel 212 via the individual recovery channel 214.

  FIG. 26 is a view showing a cross section taken along line IX-IX in FIG. Each individual recovery channel (214a, 214c) communicates with the discharge module 200 via the communication port 51. In FIG. 26, only the individual recovery passages (214a, 214c) are shown, but in another cross section, the individual supply passage 213 and the discharge module 200 communicate with each other as shown in FIG. A flow path for supplying ink from the first flow path member 50 to the recording element 15 provided on the recording element substrate 10 is formed in the support member 30 and the recording element substrate 10 included in each ejection module 200. . Further, the support member 30 and the recording element substrate 10 are provided with a flow path for collecting (circulating) a part or all of the liquid supplied to the recording element 15 to the first flow path member 50.

  Here, the common supply flow path 211 of each color is connected to the corresponding negative pressure control unit 230 (high pressure side) via the liquid supply unit 220, and the common recovery flow path 212 is connected to the negative pressure control unit 230. (Low pressure side) and the liquid supply unit 220 are connected. By this negative pressure control unit 230, a differential pressure (pressure difference) is generated between the common supply channel 211 and the common recovery channel 212. For this reason, as shown in FIGS. 25 and 26, in the liquid discharge head of this embodiment in which the respective flow paths are connected, the common supply flow path 211, the individual supply flow path 213, and the recording element are provided for each ink color. A flow in the order of the substrate 10, the individual recovery channel 214, and the common recovery channel 212 occurs.

(Description of discharge module)
FIG. 27A is a perspective view showing one discharge module 200, and FIG. 27B is an exploded view thereof. As a manufacturing method of the discharge module 200, first, the recording element substrate 10 and the flexible wiring substrate 40 are bonded onto the support member 30 provided with the liquid communication port 31 in advance. Thereafter, the terminals 16 on the recording element substrate 10 and the terminals 41 on the flexible wiring substrate 40 are electrically connected by wire bonding, and then the wire bonding portion (electrical connection portion) is covered with the sealing material 110 and sealed. . A terminal 42 of the flexible wiring board 40 opposite to the recording element substrate 10 is electrically connected to a connection terminal 93 (see FIG. 23) of the electric wiring board 90. The support member 30 is a support member that supports the recording element substrate 10, and is a flow path member that fluidly communicates the recording element substrate 10 and the flow path member 210. Therefore, the support member 30 has high flatness and is sufficiently high. Those that can be reliably bonded to the recording element substrate are preferable. As a material, for example, alumina or a resin material is preferable.

(Description of structure of recording element substrate)
FIG. 28A shows a plan view of the surface of the recording element substrate 10 on which the ejection port 13 is formed, and FIG. 28B shows an enlarged view of the portion indicated by A in FIG. FIG.28 (c) shows the top view of the back surface of Fig.28 (a). Here, the configuration of the recording element substrate 10 in the present embodiment will be described. As shown in FIG. 28A, the discharge port forming member 12 of the recording element substrate 10 is formed with four rows of discharge port rows corresponding to the respective ink colors. Hereinafter, the direction in which the discharge port array in which the plurality of discharge ports 13 are arranged is referred to as “discharge port array direction”. As shown in FIG. 28B, a recording element 15 that is a heating element for foaming a liquid by thermal energy is disposed at a position corresponding to each discharge port 13. A partition 22 defines a pressure chamber 23 having the recording element 15 therein. The recording element 15 is electrically connected to the terminal 16 by electrical wiring (not shown) provided on the recording element substrate 10. The recording element 15 generates heat based on the pulse signals input from the control circuit of the recording apparatus 1000 via the electric wiring board 90 (see FIG. 6) and the flexible wiring board 40 (see FIG. 27) to boil the liquid. Let The liquid is discharged from the discharge port 13 by the foaming force due to the boiling. As shown in FIG. 28B, along each discharge port array, a liquid supply path 18 extends on one side, and a liquid recovery path 19 extends on the other side. The liquid supply path 18 and the liquid recovery path 19 are channels extending in the direction of the discharge port array provided in the recording element substrate 10 and communicate with the discharge port 13 via the supply port 17a and the recovery port 17b, respectively.

  As shown in FIG. 28 (c), a sheet-like cover plate 20 is laminated on the back surface of the recording element substrate 10 on which the discharge ports 13 are formed. A plurality of openings 21 communicating with the passage 18 and the liquid recovery passage 19 are provided. In the present embodiment, three openings 21 are provided in the cover plate 20 for one of the liquid supply paths 18 and two openings 21 for one of the liquid recovery paths 19. As shown in FIG. 28 (b), each opening 21 of the cover plate 20 communicates with a plurality of communication ports 51 shown in FIG. 24 (a). The cover plate 20 preferably has sufficient corrosion resistance to the liquid, and high accuracy is required for the opening shape and the opening position of the opening 21 from the viewpoint of preventing color mixing. For this reason, it is preferable to use a photosensitive resin material or a silicon plate as the material of the cover plate 20 and provide the opening 21 by a photolithography process. As described above, the cover plate 20 converts the pitch of the flow path by the openings 21, and considering the pressure loss, the cover plate 20 is preferably thin and is preferably formed of a film-like member.

  FIG. 29 is a perspective view showing cross sections of the recording element substrate 10 and the cover plate 20 in XXIX-XXIX in FIG. Here, the flow of the liquid in the recording element substrate 10 will be described. The cover plate 20 has a function as a lid that forms part of the walls of the liquid supply path 18 and the liquid recovery path 19 formed on the substrate 11 of the recording element substrate 10. The recording element substrate 10 includes a substrate 11 formed of Si and a discharge port forming member 12 formed of a photosensitive resin, and a cover plate 20 is bonded to the back surface of the substrate 11. A recording element 15 is formed on one surface side of the substrate 11 (see FIG. 28), and a liquid supply path 18 and a liquid recovery path 19 extending along the ejection port array are formed on the back surface side thereof. Grooves are formed. The liquid supply path 18 and the liquid recovery path 19 formed by the substrate 11 and the cover plate 20 are connected to the common supply path 211 and the common recovery path 212 in the flow path member 210, respectively. And a liquid recovery path 19 has a differential pressure. When recording is performed by discharging liquid from the discharge port 13, the liquid in the liquid supply path 18 provided in the substrate 11 is supplied to the supply ports 17 a and 17 a by the differential pressure. It flows to the liquid recovery path 19 via the pressure chamber 23 and the recovery port 17b (arrow C in FIG. 29). By this flow, it is possible to collect the thickened ink, bubbles, foreign matters, and the like generated by evaporation from the ejection port 13 in the liquid recovery path 19 in the ejection port 13 and the pressure chamber 23 where recording is paused. Further, it is possible to prevent the ink in the ejection port 13 and the pressure chamber 23 from being thickened. The liquid recovered into the liquid recovery path 19 is communicated from the opening 21 of the cover plate 20 and the liquid communication port 31 of the support member 30 (see FIG. 27B) to the communication port 51 in the flow path member 210, the individual recovery flow path. 214 and the common recovery flow path 212 are recovered in this order. Thereafter, the recording medium 1000 is collected into the supply path. That is, the liquid supplied from the recording apparatus main body to the liquid discharge head 3 flows in the following order, and is supplied and recovered.

  The liquid first flows into the liquid ejection head 3 from the liquid connection part 111 of the liquid supply unit 220. The liquid is the joint rubber 100, the communication port 72 and the common channel groove 71 provided in the third channel member, the common channel groove 62 and the communication port 61 provided in the second channel member, and the first channel. The individual flow channel 52 and the communication port 51 provided in the member are supplied in this order. Thereafter, the pressure is supplied to the pressure chamber 23 through the liquid communication port 31 provided in the support member 30, the opening 21 provided in the cover plate 20, the liquid supply path 18 and the supply port 17 a provided in the substrate 11 in order. Of the liquid supplied to the pressure chamber 23, the liquid that has not been discharged from the discharge port 13 is the recovery port 17 b and the liquid recovery path 19 provided in the substrate 11, the opening 21 provided in the cover plate 20, and the support member 30. It flows through the liquid communication port 31 provided in the order. Thereafter, the liquid is provided in the communication port 51 and the individual flow channel 52 provided in the first flow channel member, the communication port 61 and the common flow channel 62 provided in the second flow channel member, and the third flow channel member 70. The common channel groove 71, the communication port 72, and the joint rubber 100 are sequentially flowed. Then, the liquid flows from the liquid connection part 111 provided in the liquid supply unit 220 to the outside of the liquid discharge head 3.

  In the form of the first circulation form shown in FIG. 19, the liquid flowing in from the liquid connecting portion 111 is supplied to the joint rubber 100 after passing through the negative pressure control unit 230. In the form of the second circulation form shown in FIG. 20, the liquid recovered from the pressure chamber 23 passes through the joint rubber 100 and then passes from the liquid connection unit 111 to the outside of the liquid discharge head via the negative pressure control unit 230. To flow. Further, not all the liquid that has flowed 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. That is, there is a liquid that flows from one end of the common supply channel 211 and flows from the other end of the common supply channel 211 to the liquid supply unit 220 without flowing into the individual supply channel 213. As described above, by providing a path that flows without passing through the recording element substrate 10, even if the recording element substrate 10 includes a fine flow path having a high flow resistance as in the present embodiment, the liquid is provided. The reverse flow of the circulating flow can be suppressed. As described above, in the liquid discharge head 3 of the present embodiment, it is possible to suppress the increase in the viscosity of the liquid in the pressure chamber 23 and the vicinity of the discharge port. High-quality recording can be performed.

(Description of positional relationship between recording element substrates)
FIG. 30 is a plan view showing a partially enlarged adjacent portion of the recording element substrate in two adjacent ejection modules. In this embodiment, a substantially parallelogram recording element substrate is used. The respective ejection port arrays (14a to 14d) in which the ejection ports 13 in each recording element substrate 10 are arranged are arranged so as to be inclined at a certain angle with respect to the conveyance direction of the recording medium. The ejection port arrays in the adjacent portions of the recording element substrates 10 are configured such that at least one ejection port overlaps in the conveyance direction of the recording medium. In FIG. 30, the two discharge ports on the line D are in a relationship of overlapping each other. With such an arrangement, even if the position of the recording element substrate 10 is slightly deviated from the predetermined position, black stripes and white spots in the recorded image can be made inconspicuous by driving control of the overlapping discharge ports. Even when a plurality of recording element substrates 10 are arranged in a straight line (inline) instead of in a staggered arrangement, the recording element substrate is suppressed while suppressing an increase in the length of the liquid ejection head in the recording medium conveyance direction by the configuration shown in FIG. It is possible to take measures against black streaks and white spots in the connecting portion between the ten. In this embodiment, the main plane of the recording element substrate is a parallelogram. However, the present invention is not limited to this, and the configuration of the present invention is preferable even when a rectangular, trapezoidal or other shape recording element substrate is used. Can be applied.

(Fifth embodiment)
Hereinafter, configurations of an ink jet recording apparatus 2000 and a liquid discharge head 2003 according to a fifth embodiment of the present invention will be described with reference to the drawings. In the following description, only the parts different from the fourth embodiment will be mainly described, and the description of the same parts as those of the fourth embodiment will be omitted. Also in this embodiment, the same ink circulation path as that in the third embodiment is formed. Similarly to the third embodiment, the monitoring area is set, and the ink is based on the pressure loss for each monitoring area. Control the flow rate. Thereby, local pressure loss in the liquid discharge head can be suppressed.

(Description of inkjet recording apparatus)
FIG. 38 is a diagram showing an ink jet recording apparatus 2000 to which the present embodiment can be applied and performs recording by discharging a liquid. The recording apparatus 2000 of the present embodiment performs full-color recording on a recording medium by arranging four monochromatic liquid ejection heads 2003 corresponding to each of cyan C, magenta M, yellow Y, and black K in parallel. Is different from the first embodiment. In the fourth embodiment, the number of discharge port rows that can be used per color is one, whereas in this embodiment, the number of discharge port rows that can be used per color is 20. For this reason, it is possible to perform very high-speed recording by appropriately recording the recording data to a plurality of ejection port arrays. Furthermore, even if there is a discharge port that does not discharge, reliability is improved by interpolating discharge from the discharge ports in other rows that are at positions corresponding to the discharge direction of the recording medium. And suitable for commercial records. As in the fourth embodiment, the supply system of the recording apparatus 2000, the buffer tank 1003 (see FIGS. 19 and 20), and the main tank 1006 (see FIGS. 19 and 20) are fluids for each liquid discharge head 2003. Connected. Each liquid discharge head 2003 is electrically connected to an electric control unit that transmits power and a discharge control signal to the liquid discharge head 2003.

(Explanation of circulation route)
As in the fourth embodiment, as the liquid circulation path between the recording apparatus 2000 and the liquid discharge head 2003, the first and second circulation forms shown in FIG. 19 or FIG. 20 are used as in the fourth embodiment. Can do.

(Description of liquid discharge head structure)
FIGS. 31A and 31B are perspective views showing a liquid discharge head 2003 according to the present embodiment. Here, the structure of the liquid discharge head 2003 according to the present embodiment will be described. The liquid discharge head 2003 is an ink jet line type liquid discharge head that includes 16 recording element substrates 2010 arranged linearly in the longitudinal direction of the liquid discharge head 2003 and is capable of recording with one color liquid. The liquid ejection head 2003 includes a liquid connection unit 111, a signal input terminal 91, and a power supply terminal 92, as in the first embodiment. However, since the liquid discharge head 2003 of this embodiment has more discharge port arrays than the fourth embodiment, the signal output terminal 91 and the power supply terminal 92 are arranged on both sides of the liquid discharge head 2003. This is to reduce voltage drop and signal transmission delay that occur in the wiring portion provided on the recording element substrate 2010.

  FIG. 32 is an exploded perspective view showing the liquid discharge head 2003, in which each component or unit constituting the liquid discharge head 2003 is divided for each function. The role of each unit and member and the order of liquid circulation in the liquid discharge head are basically the same as those in the fourth embodiment, but the functions for ensuring the rigidity of the liquid discharge head are different. In the fourth embodiment, the liquid discharge head support portion 81 mainly secures the liquid discharge head rigidity. However, in the liquid discharge head 2003 of the fifth embodiment, the second flow path member 2060 included in the liquid discharge unit 2300 is used. This ensures the rigidity of the liquid discharge head. In the present embodiment, the liquid discharge unit support portion 81 is connected to both ends of the second flow path member 2060, and the liquid discharge unit 2300 is mechanically coupled to the carriage of the recording apparatus 2000 to provide a liquid discharge head 2003. Perform positioning. The liquid supply unit 2220 including the negative pressure control unit 2230 and the electrical wiring board 90 are coupled to the liquid discharge unit support portion 81. Each of the two liquid supply units 2220 includes a filter (not shown).

  The two negative pressure control units 2230 are set so as to control the pressure with different relatively high and low negative pressures. Further, as shown in FIG. 31, when the negative pressure control unit 2230 on the high pressure side and the low pressure side is installed at both ends of the liquid discharge head 2003, a common supply channel extending in the longitudinal direction of the liquid discharge head 2003. And the flow of liquid in the common recovery channel face each other. In such a configuration, heat exchange is promoted between the common supply channel and the common recovery channel, and a temperature difference between the two common channels is reduced. Accordingly, there is an advantage that a temperature difference in each of the recording element substrates 2010 provided along the common flow path is reduced, and recording unevenness due to the temperature difference is less likely to occur.

  Next, details of the flow path member 2210 of the liquid discharge unit 2300 will be described. As shown in FIG. 32, the flow path member 2210 is a laminate of the first flow path member 2050 and the second flow path member 2060, and distributes the liquid supplied from the liquid supply unit 2220 to each discharge module 2200. To do. The flow path member 2210 functions as a flow path member for returning the liquid circulating from the discharge module 2200 to the liquid supply unit 2220. The second flow path member 2060 of the flow path member 2210 is a flow path member in which a common supply flow path and a common recovery flow path are formed, and has a function of mainly responsible for the rigidity of the liquid discharge head 2003. For this reason, as a material of the 2nd flow path member 2060, what has sufficient corrosion resistance with respect to a liquid and high mechanical strength is preferable. Specifically, SUS, Ti, alumina or the like can be used.

  FIG. 33A is a view showing the surface of the first flow path member 2050 on which the discharge module 2200 is mounted, and FIG. 33B shows the back surface thereof, and the second flow path member 2060 is shown. It is the figure which showed the surface contact | abutted with. Unlike the fourth embodiment, the first flow path member 2050 in the present embodiment is formed by arranging a plurality of members corresponding to each discharge module 2200 adjacent to each other. By adopting such a divided structure, a plurality of modules can be arranged to correspond to the length of the liquid discharge head 2003. For example, a relatively long scale corresponding to the B2 size or longer The present invention can be particularly preferably applied to the liquid discharge head. As shown in FIG. 33 (a), the communication port 51 of the first flow path member 2050 is in fluid communication with the discharge module 2200. As shown in FIG. The communication port 53 is in fluid communication with the communication port 61 of the second flow path member 2060. FIG. 33C shows a surface of the second flow path member 60 that comes into contact with the first flow path member 2050, and FIG. 33D shows a cross section of the central portion in the thickness direction of the second flow path member 60. FIG. 33 (e) is a diagram showing a surface of the second flow path member 2060 that contacts the liquid supply unit 2220. The functions of the flow path and the communication port of the second flow path member 2060 are the same as for one color in the fourth embodiment. One of the common flow channel grooves 71 of the second flow channel member 2060 is a common supply flow channel 2211 shown in FIG. 34, which will be described later, and the other is a common recovery flow channel 2212. The longitudinal direction of the liquid discharge head 2003, respectively. The liquid is supplied from one end side to the other end side. This embodiment differs from the fourth embodiment in that the liquid flows in the common supply channel 2211 and the common recovery channel 2212 are in opposite directions.

  FIG. 34 is a perspective view showing a liquid connection relationship between the recording element substrate 2010 and the flow path member 2210. In the flow path member 2210, a set of a common supply flow path 2211 and a common recovery flow path 2212 extending in the longitudinal direction of the liquid discharge head 2003 are provided. The communication port 61 of the second flow path member 2060 is connected in alignment with the individual communication port 53 of each first flow path member 50. Thus, a liquid supply path is formed which communicates from the communication port 72 of the second flow channel member 2060 to the communication port 51 of the first flow channel member 2050 via the common supply flow channel 2211. Similarly, a liquid supply path that communicates from the communication port 72 of the second flow channel member 2060 to the communication port 51 of the first flow channel member 2050 via the common recovery flow channel 2212 is also formed.

  35 is a view showing a cross section taken along line XXXV-XXXV in FIG. The common supply channel 2211 is connected to the discharge module 2200 via the communication port 61, the individual communication port 53, and the communication port 51. Although not shown in FIG. 35, it is apparent with reference to FIG. 34 that in another cross section, the common recovery flow path 2212 is connected to the discharge module 2200 through a similar path. As in the fourth embodiment, each ejection module 2200 and the recording element substrate 2010 are formed with a flow path communicating with each ejection port, and part or all of the supplied liquid pauses the ejection operation. It can be recirculated through the outlet. Similarly to the fourth embodiment, the common supply flow path 2211 is connected to the negative pressure control unit 2230 (high pressure side), and the common recovery flow path 2212 is connected to the negative pressure control unit 2230 (low pressure side) and the liquid supply unit 2220. Connected. Therefore, the differential pressure causes a flow that flows from the common supply flow path 2211 to the common recovery flow path 2212 through the discharge port of the recording element substrate 2010.

(Description of discharge module)
FIG. 36 (a) is a perspective view showing one discharge module 2200, and FIG. 36 (b) is an exploded view thereof. The difference from the fourth embodiment is that a plurality of terminals 16 are arranged on both sides (long sides of each printing element substrate 2010) along the plurality of ejection port array directions of the printing element substrate 2010. is there. Accordingly, two flexible wiring boards 40 that are electrically connected to the recording element substrate 2010 are also arranged on one recording element substrate 2010. This is because the number of ejection port arrays provided on the recording element substrate 2010 is 20, which is significantly larger than the eight arrays in the fourth embodiment, and the maximum distance from the terminal 16 to the recording element is shortened. This is to reduce a voltage drop and a signal delay that occur in the wiring portion in the recording element substrate 2010. Further, the liquid communication port 31 of the support member 2030 is provided in the recording element substrate 2010 and is opened so as to straddle all the ejection port arrays. Other points are the same as in the fourth embodiment.

(Description of structure of recording element substrate)
FIG. 37A is a schematic diagram of the surface of the recording element substrate 2010 on which the ejection ports 13 are arranged, and FIG. 37C is a schematic diagram showing the back surface of the surface of FIG. FIG. 37B is a schematic diagram showing the surface of the recording element substrate 2010 when the cover plate 2020 provided on the back side of the recording element substrate 2010 is removed in FIG. As shown in FIG. 37B, the liquid supply path 18 and the liquid recovery path 19 are alternately provided on the back surface of the recording element substrate 2010 along the discharge port array direction. Although the number of ejection port arrays is significantly increased as compared with the fourth embodiment, the essential difference from the fourth embodiment is that the terminals 16 are arranged in the ejection port array direction of the recording element substrate as described above. It is arranged on both sides along. A set of liquid supply path 18 and liquid recovery path 19 is provided for each discharge port array, and an opening 21 communicating with the liquid communication port 31 of the support member 2030 is provided on the cover plate 2020. The basic configuration is the same as that of the fourth embodiment.

  In addition, the description of the said embodiment does not limit the scope of the present invention. As an example, in the present embodiment, a thermal method in which bubbles are generated by a heating element to discharge a liquid has been described. However, the present invention is also applied to a liquid discharge head employing a piezo method and other various liquid discharge methods. be able to.

  In the present embodiment, an ink jet recording apparatus (recording apparatus) in which liquid such as ink is circulated between a tank and a liquid discharge head has been described. However, other forms may be used. In another embodiment, for example, two tanks are provided upstream and downstream of the liquid discharge head without circulating ink, and the ink in the pressure chamber is caused to flow by flowing ink from one tank to the other tank. It may be.

  In this embodiment, an example using a so-called line-type head having a length corresponding to the width of the recording medium has been described. However, a so-called serial-type liquid ejection head that performs recording while scanning the recording medium. The present invention can also be applied to. As a serial type liquid discharge head, for example, a configuration in which a recording element substrate for discharging black ink and a recording element substrate for discharging color ink are mounted one by one, but the present invention is not limited to this. That is, a mode in which a plurality of recording element substrates are arranged so that the discharge ports overlap in the discharge port array direction, and a short liquid discharge head shorter than the width of the recording medium is created, and the recording medium is scanned with respect to the recording medium It may be.

(Sixth embodiment)
In the configuration examples of the third to fifth embodiments, in the configuration in which ink flows from the inflow side opening 1401 to the recovery side opening 1703 via the pressure chamber 404, monitoring corresponding to each of the inflow side opening 1401 and the recovery side opening 1703 is performed. Pressure loss was calculated in area units. In the present embodiment, the pressure loss is calculated in units of monitoring regions corresponding to each region obtained by equally dividing the inside of the recording element substrate with reference to the discharge port on the end side in the recording element substrate.

  Description of the same parts as those in the third to fifth embodiments is omitted. Also in this embodiment, the same ink circulation path as in the third to fifth embodiments is formed.

(Ink flow control example)
FIG. 39 is a plan view of the surface of the recording element substrate 10 on the side where the discharge ports 13 are formed, as in FIG. 28A in the fourth embodiment. In this embodiment, an example of a recording apparatus that performs continuous recording in one pass and includes a page-wide liquid ejection head having a plurality of recording element substrates is shown. FIG. 39 shows one recording element substrate positioned on the end side of the liquid ejection head. In FIG. 39, regions 807 (1) to 807 (6) are obtained by equally dividing up to 807b, which is the discharge port at the other end, with respect to the discharge port position 807a at one end with respect to one discharge port array. The monitoring area. In this case, the local pressure loss in the liquid ejection head can be controlled by controlling the ink flow rate based on the pressure loss for each monitoring region in the same manner as in the third to fifth embodiments.

  Here, in the present embodiment, the threshold value of the ink flow rate controlled for each monitoring region is the value in the region where the distance from the opening 21 of the cover plate 2020 (FIG. 37) is the largest and the pressure loss is the largest. For example, in FIG. 39, when paying attention to both ends of the recording element substrate 10 in the arrangement direction of the discharge ports, the distance from the opening 21 of the cover plate to the end of the region is the longest in the monitoring region 807 (1). is there. Since the pressure loss in the monitoring region 807 (1) becomes the largest, the flow rate in the monitoring region 807 (1) is adopted as a threshold value. By providing a threshold value based on the region with the most severe pressure loss, it is inevitably possible to record in other monitoring regions in the recording element substrate as long as the recording duty is equal to or less than the threshold value.

  In this case, the threshold value of the recording duty in each monitoring area can be a uniform threshold value in all the areas, or a different threshold value can be provided in each area. In addition, the threshold value is not limited to this, and the threshold value can be changed for each column, or the threshold value can be provided for each printing element substrate.

  FIG. 40 has the same configuration as that of FIG. 30 in the fourth embodiment, and the recording element substrate 10a at the end of the page wide type liquid discharge head having a plurality of recording element substrates 10 and the recording elements adjacent thereto. The connection part of the board | substrate 10b is shown. As shown in FIG. 39, the recording element substrate 10a including the discharge port position 807a at the end is used as a reference for dividing the monitoring area. In this case, the recording element substrate 10a is equally divided as shown in FIG. 39 (six divisions 807 (1) to 807 (6)). At this time, as described above, the recording element substrate 10 uses a substantially parallelogram, and each of the ejection port arrays 14a to 14d in which the ejection ports 13 in the recording element substrate 10a are arranged is constant with respect to the conveyance direction of the recording medium. It is arranged to tilt at an angle. In the ejection port arrays in the adjacent portions of the recording element substrates 10a and 10b, at least one ejection port overlaps in the conveyance direction of the recording medium. Therefore, for example, the start of the monitoring area in the ejection port array 14d of the printing element substrate 10b is the ejection port position 807c of the second nozzle from the connection portion with the printing element substrate 10a. As a result, the monitoring area is shifted for each adjacent recording element substrate. Therefore, in the present embodiment, there is a place where the cover area does not include the opening 21 of the cover plate in the page wide type liquid discharge head having a plurality of recording element substrates. Control pressure loss.

  The liquid discharge head in the present embodiment is not limited to the configuration as shown in FIGS. 39 and 40, and may be, for example, a liquid discharge head having only one recording element substrate as in the second embodiment. The present embodiment can also be applied to such a liquid discharge head. Further, the numerical aperture and the number of divisions of the monitoring area are not limited to this embodiment. In this embodiment, the main plane of the recording element substrate is a parallelogram. However, the present invention is not limited to this, and the configuration of the present invention is preferable even when a rectangular, trapezoidal or other shape recording element substrate is used. Can be applied. The monitoring area may also be in a form that does not overlap the recording report of the recording medium at the joint between adjacent recording element substrates, and is not limited to this.

(Other embodiments)
The present invention can be applied to ink jet recording apparatuses of various recording methods, and the recording method includes a full line method and a serial scan method for recording an image with relative movement between a liquid discharge head and a recording medium. Etc. are optional.

  The present invention is widely applicable to an ink jet recording apparatus that records an image using an ink jet liquid discharge head capable of discharging ink, and a liquid discharge apparatus using a liquid discharge head capable of discharging various liquids. . For example, the present invention can be applied to apparatuses such as printers, copying machines, facsimiles having a communication system, word processors having a printer unit, and industrial recording apparatuses combined with various processing apparatuses. It can also be used for applications such as biochip fabrication and electronic circuit printing.

101 Recording device (liquid ejection device)
102 Liquid discharge head (liquid discharge head)
104 Recording medium (medium)
105 CPU (control unit)
203 Discharge port 303 Common channel 304 Branch channel (supply channel)

Claims (12)

A liquid discharge apparatus having a liquid discharge head comprising a plurality of discharge ports for discharging liquid,
A supply path for supplying a liquid to a plurality of regions of the liquid discharge head communicating with the plurality of discharge ports;
Control means for controlling the liquid discharge amount per unit time from the liquid discharge head so that the liquid flow rate for each region is a predetermined amount or less;
A liquid ejection apparatus comprising:   The liquid ejection apparatus according to claim 1, further comprising a calculation unit that calculates the liquid flow rate based on ejection data for ejecting liquid from the plurality of ejection ports. Moving means for relatively moving the liquid discharge head and a medium to which the liquid discharged from the liquid discharge head is applied;
The liquid ejecting apparatus according to claim 1, wherein the control unit controls a discharge frequency at which the liquid discharge head discharges a liquid and a moving speed of the moving unit.   The liquid ejection apparatus according to claim 1, wherein the supply path is provided for each of the plurality of regions.   The liquid ejection apparatus according to claim 1, wherein the region includes a region where the supply path is provided and a region where the supply path is not provided.   6. The liquid ejection apparatus according to claim 1, wherein the supply path is branched in units of the region corresponding to a plurality of the ejection ports. The plurality of discharge ports are arranged to form a plurality of discharge port arrays,
6. The liquid ejection apparatus according to claim 1, wherein the supply path is branched in units of the area corresponding to each of the ejection port arrays. The liquid discharge head includes a plurality of liquid discharge substrates on which the discharge ports are formed,
6. The liquid ejection apparatus according to claim 1, wherein the supply path is branched in units of the region corresponding to each of the liquid ejection substrates. The liquid ejection head includes a plurality of flow paths communicating with the plurality of ejection openings, and a plurality of openings communicating with each of the plurality of flow paths.
The liquid ejection apparatus according to claim 1, wherein the supply path is branched in units of the regions corresponding to the openings. The liquid discharge head includes a discharge energy generating element for discharging a liquid, a pressure chamber having the discharge energy generating element therein, and a recovery path for recovering the liquid from the pressure chamber,
The liquid ejecting apparatus according to claim 1, further comprising a circulation unit that circulates the liquid through the supply path, the pressure chamber, and the recovery path. An inkjet recording apparatus including the liquid ejection apparatus according to claim 1,
The liquid discharge head is an inkjet liquid discharge head capable of discharging liquid ink supplied through the supply path from the plurality of discharge ports;
The inkjet recording apparatus includes a moving unit that relatively moves the inkjet liquid ejection head and a recording medium to which ink ejected from the inkjet liquid ejection head is applied. A liquid discharge method for discharging liquid from a plurality of discharge ports of a liquid discharge head,
Supplying a liquid to each of a plurality of regions of the liquid discharge head communicating with the plurality of discharge ports through a plurality of supply paths corresponding to the plurality of regions;
Controlling the liquid discharge amount per unit time from the liquid discharge head so that the liquid flow rate for each region is a predetermined amount or less;
A liquid discharge method comprising: