Method for Adjusting Recording Position

Abstract

To reduce misalignment of recording positions between recording heads caused by heat expansion without causing increase of a data processing load.SOLUTION: In an adjustment method of a recording position, recording element substrates 10 of a reference head 3A and an adjustment target head 3B are adjusted to a target temperature and liquid is circulated through the recording element substrates 10. After thermal expansion of the reference head 3A and the adjustment target head 3B reaches a steady state, a first recording region 171 being a recording region of the reference head 3A and a second recording region 174 being a recording region of the adjustment target head 3B in a longitudinal direction are obtained from an image recorded by using all recording elements 15. Then, used regions to be used for actual recording are set among the recording elements arranged on the reference head 3A and the adjustment target head 3B on the basis of the first recording region 171 and the second recording region 174.SELECTED DRAWING: Figure 17

Description

Technical Field

[0001] The present invention relates to a method for adjusting a recording position.

Background Art

[0002] A line-type inkjet recording apparatus that records an image using a plurality of recording heads having a length corresponding to the width of a recording medium can output the image at high speed. However, a long recording head may thermally expand due to a heat treatment for maintaining an appropriate ejection operation. In particular, in a recording apparatus having a configuration in which ink is circulated through the recording head in order to maintain a normal ejection operation, the recording head is likely to expand due to the heat of the ink flowing through the recording head. And in this case, if the degree of thermal expansion differs among the plurality of recording heads, a recording position shift between the recording heads occurs on the recording medium. When individual recording heads eject different inks, this recording position shift may be perceived as a color shift of the image.

[0003] Patent Document 1 discloses a method in which dummy data is input to a recording head with small thermal expansion to expand the apparent recording width and bring it closer to the recording width of a recording head with large thermal expansion.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the method of Patent Document 1, it is necessary to generate dummy data according to the degree of thermal expansion and image data, resulting in a large data processing load. Also, the longer the recording head is, the greater the variation in the temperature distribution within the recording head becomes, and the prediction process of the thermal expansion amount becomes complicated. That is, the processing load for generating dummy data according to the degree of thermal expansion increases as the liquid ejection head is longer, making high-speed processing difficult.

[0006] The present invention has been made to solve the above problems. Therefore, an object of the present invention is to reduce the recording position shift between recording heads due to thermal expansion in an inkjet recording apparatus without causing an increase in data processing load.

Means for Solving the Problems

[0007] To achieve this, the present invention includes a plurality of recording element substrates on which a plurality of recording elements are arranged continuously in a first direction, temperature control means for adjusting the temperature of the recording element substrates, and circulation means for circulating a liquid through the recording element substrates. A method for adjusting the recording positions in the first direction of a first recording head and a second recording head that thermally expand according to the circulation of the liquid by the temperature control means and the circulation means, wherein the first recording head and the second recording head are arranged in a second direction intersecting the first direction, and are mounted on the recording apparatus with one side in the first direction as a fixed side and the other side as a movable side that displaces according to thermal expansion. For the first recording head and the second recording head, temperature control is performed under the same conditions by the temperature control means and the circulation means, and the plurality of recording elements are driven to eject the liquid to record a test pattern on a recording medium, and a first recording area that is the recording area of the first recording head in the first direction and a second recording area that is the recording area of the second recording head are acquired. An acquisition step, and based on the first recording area, a first use area to be actually used for recording among the plurality of recording elements arranged in the first recording head is set, and based on the first use area and the second recording area, a second use area to be actually used for recording among the plurality of recording elements arranged in the second recording head is set. It is characterized by having a setting step. [Effect of the Invention]

[0008] According to the present invention, it is possible to reduce the recording position shift between recording heads due to thermal expansion without causing an increase in the data processing load. [Brief Description of the Drawings]

[0009]

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Mode for Carrying Out the Invention

[0010] (First Embodiment) <Overall Configuration of the Recording Device> FIGS. 1(a) and (b) are diagrams showing an example of a recording device that can be used in the present embodiment. The recording device of the present embodiment is an inkjet recording device (hereinafter simply referred to as the recording device) 1000 that records a color image on a recording medium S by ejecting cyan (C), magenta (M), yellow (Y), and black (Bk) inks. In the figure, the X direction is the conveyance direction of the recording medium S, the Y direction is the width direction of the recording medium, and the Z direction is the vertically upward direction.

[0011] Fig. 1(a) shows a recording apparatus 1000 in which a liquid ejection head (hereinafter referred to as a recording head) 3 directly applies ink to a recording medium S conveyed in the X direction. The recording medium S is mounted on a conveyance unit 1 and is conveyed in the X direction at a predetermined speed below four recording heads 3 that eject different inks. In Fig. 1(a), the four recording heads 3 are arranged in the X direction in the order of cyan, magenta, yellow, and black, and ink is applied to the recording medium S in this order. In each recording head 3, a plurality of ejection ports for ejecting ink are arranged in the Y direction.

[0012] Fig. 1(b) shows a recording apparatus 1000 in which the ink ejected from the four-color recording heads 3 is transferred to the recording medium S via an intermediate transfer drum 2. The four recording heads 3 that eject different inks are arranged such that the ejection port surfaces face the surface of the columnar intermediate transfer drum 2. When the recording medium S conveyed in the X direction by a conveyance roller 4 passes through the nip portion between the intermediate transfer drum 2 and a transfer roller 5, the ink applied to the intermediate transfer drum 2 is transferred to the recording medium S. The recording head 3 of the present embodiment can be used in either of the recording apparatuses 1000 shown in Figs. 1(a) and (b).

[0013] In addition, in Figs. 1(a) and (b), cut paper is shown as the recording medium S, but the recording medium S2 may be continuous paper supplied from a roll paper.

[0014] Fig. 2 is a block diagram for explaining the control configuration in the recording apparatus 1000. The control unit 500 is composed of a CPU or the like, and controls the entire recording apparatus 1000 while using the RAM 502 as a work area according to the programs and various parameters stored in the ROM 501. The control unit 500 performs predetermined image processing on the image data received from the host device 600 connected externally according to the programs and parameters stored in the ROM 501, and generates ejection data that can be ejected by the recording head 3. Then, the recording head 3 is driven according to this ejection data to eject ink at a predetermined frequency.

[0015] During the ejection operation by the recording head 3, the control unit 500 drives the conveyance motor 503 to convey the recording medium S in the X direction at a speed corresponding to the drive frequency. As a result, an image according to the image data received from the host device 600 is recorded on the recording medium S. In the ROM 501, information on the usage area of the ejection ports used for ejection in the recording head 3 is stored in a rewritable manner for each recording head 3. The method for setting the usage area will be described in detail later.

[0016] Although not shown in FIG. 2, a plurality of recording element substrates 10 (see FIGS. 3 and 4) are arranged in the recording head 3. And, a plurality of temperature sensors 301 for detecting the temperature of the recording element substrate 10 and a plurality of sub-heaters 302 for heating the recording element substrate 10 to a predetermined set temperature are provided on each recording element substrate 10. In FIG. 2, for simplicity of explanation, the plurality of temperature sensors 301 and sub-heaters 302 are shown combined into one. When performing the recording operation, the control unit 500 drives the sub-heater 302 based on the temperature detected by the temperature sensor 301 to keep each recording element substrate 10 at an appropriate temperature. In the present embodiment, in a general recording operation, the recording element substrate 10 is kept at 65°C.

[0017] The liquid circulation unit 504 is a unit for supplying liquid (ink) to the recording head 3 while circulating it. The liquid circulation unit 504 controls a system for circulating the ink under the management of the control unit 500. In FIG. 2, for simplicity, the recording head 3 and the liquid circulation unit 504 for one color are shown, but actually, the recording head 3 and the liquid circulation unit 504 for four colors are controlled by the control unit.

[0018] <Ink Circulation System> FIGS. 3(a) and (b) are diagrams for explaining the ink circulation system controlled by the liquid circulation unit 504.

[0019] In each of FIGS. 3(a) and 3(b), the ink stored in the buffer tank 1001 is supplied to the recording head 3, and the ink not consumed by ejection is recovered back into the buffer tank 1001 again. That is, the ink circulates between the buffer tank 1001 and the recording head 3. When the amount of ink stored in the buffer tank 1001 becomes equal to or less than a predetermined amount, the replenishing pump P0 is driven, and the ink stored in the main tank 1002 is replenished into the buffer tank 1001. The buffer tank 1001 is provided with an air communication port (not shown), and the bubbles contained in the ink recovered from the recording head 3 rise to the water surface by buoyancy and are released into the atmosphere.

[0020] The recording head 3 of the present embodiment has a discharge unit 300 that discharges ink according to discharge data, and two liquid supply units 220 for adjusting the pressure of the ink supplied to the discharge unit 300. A first negative pressure control unit 230 and a second negative pressure control unit 231 for controlling the pressure of the ink flowing into the discharge unit 300 are respectively arranged in the two liquid supply units 220.

[0021] FIG. 3(a) shows an example in which the first negative pressure control unit 230 and the second negative pressure control unit 231 are arranged upstream of the discharge unit 300 in the ink flow. The ink stored in the buffer tank 1001 is discharged by the first circulation pump P1 and then divided into two branches and supplied to the left and right liquid supply units 220. The supplied ink is supplied to the first negative pressure control unit 230 and the second negative pressure control unit 231 through the respective filters 221.

[0022] The control pressure of the first negative pressure control unit 230 is set to a weak negative pressure (a negative pressure with a small pressure difference from the atmospheric pressure). The control pressure of the second negative pressure control unit 231 is set to a strong negative pressure (a negative pressure with a large pressure difference from the atmospheric pressure). Since the pressure realized by the first negative pressure control unit 230 is higher (the negative pressure is lower) than the pressure realized by the second negative pressure control unit 231, in the figure, the first negative pressure control unit 230 is shown as H and the first negative pressure control unit 230 is shown as L.

[0023] The ink whose pressure is adjusted by the first negative pressure control unit 230 is recovered into the buffer tank 1003 via the common supply channel 211 of the discharge unit 300 by the suction force of the second circulation pump P2. The ink whose pressure is adjusted by the second negative pressure control unit 231 is recovered into the buffer tank 1003 via the common recovery channel 212 of the discharge unit 300 by the suction force of the third circulation pump P3. The adjustment pressures in the first negative pressure control unit 230 and the second negative pressure control unit 231 are maintained within an appropriate range by driving the second circulation pump P2 and the third circulation pump P3.

[0024] The amount of liquid flowing through the common supply channel 211 and the common recovery channel 212 varies according to the frequency at which the discharge unit 300 discharges ink, that is, the duty of the image. As in this embodiment, by providing the first negative pressure control unit 230 and the second negative pressure control unit 231 on the upstream side of the discharge unit 300, the pressure of the ink in the discharge unit 300 can be maintained within a certain range regardless of the duty of the image.

[0025] In the discharge unit 300, a plurality of recording element substrates 10 are arranged in the extending direction (Y direction) of the common supply channel 211 and the common recovery channel 212. Each recording element substrate 10 is connected to the common supply channel 211 via an individual supply channel 213a and is connected to the common recovery channel 212 via an individual recovery channel 213b. Since there is a pressure difference between the ink flowing through the common supply channel 211 and the ink flowing through the common recovery channel 212, in each recording element substrate 10, a flow of ink from the individual supply channel 213a toward the individual recovery channel 213b is formed.

[0026] In the above ink circulation configuration, as the first circulation pump P1, it is preferable to use one that can obtain a head pressure of a certain level or higher within the range of the ink circulation flow rate realized when the discharge unit 300 is driven. A turbo pump, a positive displacement pump, or the like can be used. Specifically, a diaphragm pump or the like is applicable. Further, instead of the first circulation pump P1, a head tank arranged with a certain head difference with respect to the first negative pressure control unit 230 and the second negative pressure control unit 231 can also be used.

[0027] As the second circulation pump P2 and the third circulation pump P3, a positive displacement pump having a quantitative liquid feeding ability can be used. Specifically, a tube pump, a gear pump, a diaphragm pump, a syringe pump, or the like can be mentioned. Further, a form in which a general constant flow rate valve or relief valve is arranged at the pump outlet to ensure a constant flow rate may also be adopted.

[0028] As the first negative pressure control unit 230 and the second negative pressure control unit 231, a mechanism similar to a so-called "pressure reducing regulator" can be adopted. When a pressure reducing regulator is used, as shown in Fig. 3(a), it is preferable to arrange the first circulation pump P1 so as to pressurize the upstream side of the first negative pressure control unit 230 and the second negative pressure control unit 231. By doing so, the influence of the head pressure on the discharge unit 300 of the buffer tank 1001 can be suppressed, so that the degree of freedom in the layout of the buffer tank 1003 in the recording apparatus 1000 can be improved.

[0029] In the ejection unit 300 shown in Fig. 3(a), when the recording apparatus 1000 is performing a recording operation, a certain amount of ink flows through each recording element substrate 10 regardless of the presence or absence of ejection data. Therefore, it is possible to suppress thickening of the ink at ejection ports with a low ejection frequency, and to discharge thickened ink or foreign matter from the ejection unit 300. Further, as shown in Fig. 3(a), by making the flow direction of the ink in the common supply channel 211 opposite to the flow direction of the ink in the common recovery channel 212, heat exchange can be promoted between these opposing channels. As a result, the temperature gradient in the longitudinal direction (Y direction) within the recording head 3 can be reduced, and variation in ejection amounts among the plurality of recording element substrates 10 can be suppressed.

[0030] However, if the ink flow rate in the ejection unit 300 is set to be too large, a large negative pressure difference may occur between the recording element substrates 10 due to the pressure loss in the channels, and density unevenness may occur in the output image. Therefore, it is preferable that the ink flow rate in the ejection unit 300 be appropriately adjusted according to the thickening at ejection ports with a low ejection frequency, the temperature variation between the recording element substrates 10, and the degree of pressure loss.

[0031] Fig. 3(b) shows an example in which the first negative pressure control unit 230 and the second negative pressure control unit 231 are arranged on the downstream side of the ejection unit 300 in the ink flow. The configuration shown in Fig. 3(b) also provides substantially the same effects as those described with reference to Fig. 3(a). Hereinafter, the differences from the configuration of Fig. 3(a) will be described.

[0032] In Fig. 3(b), the ink flows in the direction opposite to that in Fig. 3(a). That is, the ink stored in the buffer tank 1001 is supplied to the common supply channel 211 of the liquid supply unit 220 by the second circulation pump P2, and is supplied to the common recovery channel 212 of the liquid supply unit 220 by the third circulation pump P3. The ink that has passed through the common supply channel 211 is recovered into the buffer tank 1001 via the first negative pressure control unit 230 by the first circulation pump P1 acting as a negative pressure source. The ink that has passed through the common recovery channel 212 is recovered into the buffer tank 1001 via the second negative pressure control unit 231 by the first circulation pump P1 acting as a negative pressure source.

[0033] As the first negative pressure control unit 230 and the second negative pressure control unit 231 in Fig. 3(b), a mechanism similar to the so-called "back pressure regulator" can be adopted. By providing the first negative pressure control unit 230 and the second negative pressure control unit 231 serving as back pressure regulators on the downstream side of the discharge unit 300, the pressure of the ink in the discharge unit 300 can be maintained within a certain range regardless of the duty of the image. Also in the configuration of Fig. 3(b), similar to the configuration of Fig. 3(a), the influence of the head pressure of the buffer tank 1001 on the discharge unit 300 can be suppressed, so that the degree of freedom in the layout of the buffer tank 1003 in the recording apparatus 1000 can be increased.

[0034] In the case of the configuration of Fig. 3(b), the ink supplied from the buffer tank 1001 is directly supplied to the discharge unit 300 via the filter 221. Therefore, even if dust or foreign matter is generated in the first negative pressure control unit 230 or the second negative pressure control unit 231, it will not mix into the liquid discharge unit.

[0035] Also, in the case of the configuration of Fig. 3(b), the maximum value of the flow rate of the ink sent from the buffer tank 1001 to the discharge unit 300 can be suppressed to be lower than that in the configuration of Fig. 3(a). The reason is explained below.

[0036] First, let Qa be the flow rate required to circulate the ink in the ejection unit 300 in a state without an ejection operation. The flow rate Qa is defined as the minimum flow rate required to keep the ejection unit 300 at an appropriate temperature when the recording apparatus 1000 is in the standby state. Also, let Qb be the flow rate of the ink consumed by the ejection unit 300 in a state where ejection operations are performed at the maximum frequency at all ejection ports.

[0037] In the case of the configuration of FIG. 3(a), the sum of the set flow rates of the second circulation pump P2 on the high-pressure side and the third circulation pump P3 on the low-pressure side is Qa. Therefore, when ejection operations are performed at the maximum frequency at all ejection ports, the maximum value of the ink supply amount to the ejection unit 300 is Qa + Qb. On the other hand, in the case of the configuration of FIG. 3(b), the sum of the set flow rates of the second circulation pump P2 on the high-pressure side and the third circulation pump P3 on the low-pressure side may be the larger value of Qa and Qb. That is, in the configuration of FIG. 3(b), the total circulation amount of the ink and thus the power of the pump can be suppressed lower than in the configuration of FIG. 3(a), and as a result, the degree of freedom of the applicable circulation pump can be increased. And such an effect becomes more prominent as Qa and Qb increase, that is, as the size of the line head increases.

[0038] On the other hand, in the case of the configuration of FIG. 3(b), the negative pressure acting on each nozzle is larger than in the configuration of FIG. 3(a), and satellites may be prominent in the output image. This is because in the configuration of FIG. 3(b), the maximum value of the flow rate flowing in the ejection unit 300 is the same as the flow rate flowing in a state without an ejection operation. Therefore, the lower the duty of the image, the larger the negative pressure acting on each ejection port. For this reason, satellites are generated at each ejection port even in an image with a low duty, and such satellites are more prominent in an image with a lower duty. Such a tendency becomes more prominent particularly when the widths of the common supply channel 211 and the common recovery channel 212 are reduced for miniaturization of the liquid ejection head. On the other hand, in the configuration of FIG. 3(a), the negative pressure acting on each nozzle becomes larger when the duty is high. In this case, even if satellites are generated, the satellites are less prominent in an image with a high duty.

[0039] Considering each of the features described above, the ink circulation configuration of this embodiment can adopt either of FIGS. 3(a) and (b). In FIGS. 3(a) and (b), the ink circulation configuration for one color of ink is shown, but in reality, such a configuration is provided for each ink color. Also, in the above, in order to reduce the temperature gradient in the longitudinal direction (Y direction) within the recording head 3, the flow directions of the liquids in the common supply channel 211 and the common recovery channel 212 are set to be opposite directions, but these may be in the same direction.

[0040] <Configuration of the recording head> FIGS. 4(a) and (b) are external perspective views of the recording head 3 that can be used in this embodiment. FIG. 4(a) is a view of the recording head 3 seen from obliquely below, and FIG. 4(b) is a view of the recording head 3 seen from obliquely above. In the recording head 3, recording head support portions 80 for ensuring rigidity are provided on both sides in the Y direction, which is the longitudinal direction, and the liquid supply units 220 described in FIGS. 3(a) and (b) are accommodated in each of these two recording head support portions 80. In the figure, the first negative pressure control unit 230 and the second negative pressure control unit 231 protrude above (+Z direction) the recording head support portion 80. A liquid connection portion 111 for connecting to the buffer tank 1001 is provided on the lower surface of the recording head support portion 80.

[0041] On the lower surface of the recording head 3, a plurality of recording element substrates 10 are linearly arranged along the Y direction at a distance corresponding to the width of the A3 size. On each individual recording element substrate 10, ejection port rows formed by arranging a plurality of ejection ports in the Y direction are arranged in parallel in the X direction for 20 rows (see FIG. 10).

[0042] On both side surfaces in the X direction, which is the short side direction of the recording head 3, there are provided electrical wiring boards 90 extending in the Y direction. Each of the recording element boards 10 is connected to the electrical wiring boards 90 on both sides via flexible wiring boards 40. Each of the electrical wiring boards 90 is provided with two power supply terminals 92 for receiving power from the main body of the recording apparatus 1000 and four signal input terminals 91 for receiving ejection signals. By aggregating the wirings by the electrical circuits within the electrical wiring boards 90, the number of signal input terminals 91 and power supply terminals 92 can be kept less than the number of recording element boards 10, and the connection work when attaching and detaching the recording head 3 to and from the recording apparatus 1000 can be simplified.

[0043] FIG. 5 is an exploded perspective view of the recording head 3. The recording head 3 mainly includes a liquid supply unit 220, an electrical wiring board 90, a recording head support portion 80, and an ejection unit 300. The ejection unit 300 has a flow path member 210 for circulating ink through each recording element board 10, a plurality of ejection modules 200 composed of the recording element boards 10 and the flexible wiring boards 40, and a cover member 130 covering the outer periphery of the ejection module 200.

[0044] The flow path member 210 has a first flow path member 50 that is fluidly connected to the recording element board 10 and a second flow path member 60 that is fluidly connected to the liquid supply unit 220. In the first flow path member 50, the individual supply flow paths 213a and individual recovery flow paths 213b described with reference to FIGS. 3(a) and 3(b) are formed. In the second flow path member 60, the common supply flow path 211 and common recovery flow path 212 described with reference to FIGS. 3(a) and 3(b) are formed. The second flow path member 60 is coupled to the recording head support portion 80 and, together with the recording head support portion 80, bears the rigidity of the recording head 3. As the material of the second flow path member 60, those having sufficient corrosion resistance against the liquid and high mechanical strength are preferable. Specifically, SUS, Ti, alumina, etc. can be preferably used.

[0045] The cover member 130 is a member having a frame-shaped surface provided with a long cover opening 131. From the cover opening 131 of the cover member 130, a plurality of recording element substrates 10 and a sealing material 110 (see FIG. 9) for sealing the connection portion between each recording element substrate 10 and the flexible wiring substrate 40 are exposed. The frame portion around the cover opening 131 functions as a contact surface when a cap provided in the recording apparatus 1000 caps the discharge port surface of the recording head 3. Around the cover opening 131, in order to form a suitable closed space during capping, it is preferable to apply an adhesive, a sealing material, a filling material, etc. so as to fill the unevenness and gaps on the discharge port surface of the discharge unit 300.

[0046] When assembling the recording head 3, the discharge unit 300 is attached to the lower surface of the recording head support portion 80, two electric wiring substrates 90 are attached to both side surfaces of the recording head support portion 80, and the liquid supply unit 220 is mounted in the recording head support portion 80. Note that a joint rubber 100 for suppressing ink leakage is disposed at the connection portion between the liquid supply unit 220 and the discharge unit 300.

[0047] FIG. 6 is a diagram showing a state in which the recording head 3 is mounted on a carriage 70 provided in the recording apparatus 1000. The carriage 70 has a box shape capable of mounting the recording head 3, and a movable portion 71 that is slidable in the Y direction is provided on one side in the longitudinal direction, which is the Y direction.

[0048] In the present embodiment, by providing the movable portion 71 on one side of the carriage 70 in this manner, when the recording head 3 expands in the longitudinal direction, the movable portion 71 of the carriage 70 moves in the +Y direction. Therefore, even when the recording head 3 thermally expands in the longitudinal direction, the carriage 70 can support the recording head 3 without distorting it.

[0049] Figs. 7(a) to (e) are diagrams for explaining the detailed configuration of the flow path member 210. Figs. 7(a) and (b) show the front and back surfaces of the first flow path member 50, and Figs. 7(c) to (e) show the front surface, middle layer cross-section, and back surface of the second flow path member 60, respectively. Fig. 7(a) becomes the contact surface with the recording element substrate 10, and Fig. 7(e) becomes the contact surface with the liquid supply unit 220. Also, the surface of the first flow path member 50 shown in Fig. 7(b) and the surface of the second flow path member 60 shown in Fig. 7(c) are in contact with each other.

[0050] The first flow path member 50 includes a plurality of individual members 52 arranged in the Y direction, and one recording element substrate 10 is associated with each individual member 52. With such a configuration, by adjusting the number of ejection modules 200 and the number of individual members 52 arranged, recording heads 3 of various sizes can be assembled.

[0051] As shown in Fig. 7(a), on the surface of the first flow path member 50 that contacts the recording element substrate 10, communication paths 51 are formed that are in fluid connection with the recording element substrate 10 and serve as the individual supply flow paths 213a and individual recovery flow paths 213b described in Figs. 3(a) and (b). Individual communication ports 53 that are in fluid communication with the second flow path member 60 are formed in each communication path 51.

[0052] As shown in Fig. 7(c), on the surface of the second flow path member 60 that contacts the first flow path member 50, communication ports 61 that communicate with the individual communication ports 53 of the first flow path member 50 are formed. For each individual member 52, one pair of supply and recovery communication ports 61 are provided.

[0053] As shown in Fig. 7(d), in the middle layer of the second flow path member 60, common flow path grooves 62 extending in the Y direction that serve as the common supply flow path 211 and common recovery flow path 212 described in Figs. 3(a) and (b) are formed. Common communication ports 63 that are in fluid communication with the liquid supply unit 220 are formed at both ends of the common flow path grooves 62.

[0054] Figs. 8(a) and 8(b) are a perspective view and a cross-sectional view for explaining the flow path structure formed inside the flow path member 210. Fig. 8(a) is an enlarged perspective view of the flow path member 210 as viewed from the Z direction, and Fig. 8(b) is a cross-sectional view taken along line VIIIb-VIIIb of Fig. 8(a).

[0055] The common supply flow path 211 and the common recovery flow path 212 extending in the longitudinal direction (Y direction) of the second flow path member 60 are connected to the first flow path member 50 via the communication port 61 of the second flow path member 60 and the individual communication port 53 of the first flow path member 50. That is, the second flow path member 60 and the first flow path member 50 are laminated with the communication port 61 and the individual communication port 53 aligned. Further, the recording element substrate 10 of the ejection module 200 is placed on the communication path 51 of the first flow path member 50 via the support member 30. Although the individual communication port 53 corresponding to the common recovery flow path 212 is not shown in Fig. 8(b), it is clear from Fig. 8(a) that it will be shown in another cross-section.

[0056] As already described, the common supply flow path 211 is connected to the relatively high-pressure first negative pressure control unit 230, and the common recovery flow path 212 is connected to the relatively low-pressure second negative pressure control unit 231. For this reason, an ink supply path to the recording element substrate 10 is formed, which consists of the common communication port 63 (see Fig. 7), the common supply flow path 211, the communication port 61, the individual communication port 53, the communication path 51 (individual supply flow path 213a), and the recording element substrate 10. Similarly, an ink recovery path is formed, which consists of the recording element substrate 10, the communication path 51 (individual recovery flow path 213b), the individual communication port 53, the communication port 61, the common recovery flow path 212, and the common communication port 63 (see Fig. 7). While the ink is circulated in this way, in the recording element substrate 10, an ejection operation is performed according to the ejection data, and the ink that has not been consumed by the ejection operation among the ink supplied through the ink supply path is recovered through the ink recovery path.

[0057] Figs. 9(a) and (b) are a perspective view and an exploded view of the ejection module 200. The ejection module 200 is manufactured by adhering the recording element substrate 10 to the support member 30, electrically connecting the terminals 16 of the recording element substrate 10 and the terminals 41 of the flexible wiring substrate 40 by wire bonding, and sealing the wire bonding portion with a sealing material 110. In the flexible wiring substrate 40, the terminal 42 located at a position opposite to the recording element substrate 10 is electrically connected to the electrical wiring substrate 90 (see Fig. 4). The recording element substrate 10 of the present embodiment is provided with 20 rows of ejection port rows, that is, 20 rows of recording element rows, and one of the 10 rows on one side and the 10 rows on the other side are associated with different flexible wiring substrates 40. In this way, by connecting the flexible wiring substrates 40 to both sides of the recording element substrate 10, the distance between each recording element row arranged on the recording element substrate 10 and the terminal 16 can be made as short as possible, and the voltage drop and signal transmission delay occurring in the wiring portion can be reduced. However, when the number of recording element rows is small or when the voltage drop or the like is not a serious problem, the flexible wiring substrate 40 may be arranged only on one side of the recording element substrate 10.

[0058] In the support member 30, a liquid supply port 31 serving as an opening is formed at a position corresponding to the communication path 51 described with reference to Figs. 8(a) and (b) so as to straddle all the ejection port rows of the recording element substrate 10. The support member 30 is both a support for the recording element substrate 10 and one of the flow path members located between the recording element substrate 10 and the flow path member 210. Therefore, it is preferable that the support member 30 has high flatness and can be joined to the recording element substrate 10 with sufficiently high reliability. Examples of suitable materials that can be used include alumina and resin materials.

[0059] <Configuration of the recording element substrate> FIGS. 10(a) to 10(c) and FIG. 11 are diagrams for explaining the structure of the recording element substrate 10 in detail. FIG. 10(a) is a top view of the recording element substrate 10, FIG. 10(b) is an enlarged perspective view of the region Xb shown in FIG. 10(a), and FIG. 10(c) is a rear view of the recording element substrate 10. Further, FIG. 11 is a cross-sectional view taken along the line XI-XI of FIG. 10(a). As shown in FIG. 11, one recording element substrate 10 is formed by laminating a discharge port forming member 12 made of a photosensitive resin, a substrate 11 made of silicon, and a thin film cover plate 20.

[0060] As shown in FIG. 10(a), the recording element substrate 10 of the present embodiment has a parallelogram shape. Further, in the recording element substrate 10, terminals 16 for electrically connecting to the flexible wiring substrate 40 are formed at both ends in the short side direction (±X direction) of the recording head 3.

[0061] In the discharge port forming member 12, a discharge port row in which discharge ports 13 for discharging the same color ink are arranged in the Y direction is arranged in parallel in the X direction for 20 rows. For this reason, the discharge data for one pixel may be discharged by any one of the 20 discharge ports at the same position in the Y direction, and the driving frequency of the recording head 3 can be increased while ensuring the driving period of each discharge port. Further, even if a non-discharging discharge port occurs, the discharge data of the discharge port can be allocated to another discharge port at the same position in the Y direction, so that an image without missing parts can be recorded.

[0062] FIG. 10(b) is an enlarged view of the region Xb shown in FIG. 10(a). In the discharge port forming member 12, a plurality of pressure chambers 23 are formed by arranging the partition walls 22 in the Y direction at a predetermined pitch to partition them. Recording elements 15, which are electrothermal conversion elements, are arranged at positions on the surface of the substrate 11 corresponding to the individual pressure chambers 23. The recording element 15 is electrically connected to the terminal 16 by wiring (not shown) provided on the recording element substrate 10. The control unit 500 (see FIG. 2) of the recording apparatus 1000 transmits a pulse voltage according to the discharge data, and this pulse voltage is applied to the recording element 15 via the electric wiring board 90 and the flexible wiring board 40. Then, the recording element 15 generates heat, film boiling occurs in the liquid accommodated in the pressure chamber 23, and a part of the ink accommodated in the pressure chamber 23 is discharged to the outside from the discharge port 13 by the growth energy of the generated bubbles.

[0063] On the other hand, on both sides in the X direction of each discharge port row, a liquid supply path 18 that connects to the individual supply flow paths 213a of the flow path member 210 and connects to the plurality of pressure chambers 23, and a liquid recovery path 19 that connects to the individual recovery flow paths 213b of the flow path member 210 and connects to the plurality of pressure chambers 23 extend in the Y direction. Also, as shown in the cross-sectional view of FIG. 11, a supply port 17a that communicates with the pressure chamber 23 is formed in the liquid supply path 18, and a recovery port 17b that communicates with the pressure chamber 23 is formed in the liquid recovery path 19, corresponding to each pressure chamber 23. The liquid inside the pressure chamber 23 flows between the inside and outside of the pressure chamber 23 via the supply port 17a and the recovery port 17b. That is, regardless of whether or not ink is discharged from the discharge port 13 for the discharge operation, fresh ink is supplied to the pressure chamber 23.

[0064] Furthermore, as shown in FIG. 10(c), on the cover plate 20 disposed on the side in contact with the first flow path member 50, a plurality of openings 21 are formed at positions corresponding to the communication path 51 of the first flow path member 50 and the liquid supply port 31 of the support member 30. 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 are provided for one of the liquid recovery paths 19. As shown in FIG. 10(b), each opening 21 of the cover plate 20 communicates with the plurality of communication paths 51 shown in FIG. 7(a). In such a cover plate 20, sufficient corrosion resistance against the liquid (ink) and high layout accuracy of the plurality of openings 21 are required. Therefore, the plurality of cover plates 20 are preferably formed by a photolithography process using, for example, a photosensitive resin material or a silicon plate.

[0065] FIG. 12 is a diagram showing the connection state of adjacent recording element substrates 10. The recording head 3 of the present embodiment has a parallelogram shape, and two adjacent recording element substrates 10 are continuously arranged in the Y direction while abutting their side edges against each other. At this time, at the connection portion of the two recording element substrates 10, at least one discharge port 13 located at the outermost end of one recording element substrate 10 and the discharge port 13 located at the outermost end of the other recording element substrate 10 are laid out at the same position in the Y direction. In other words, the inclination angle of the parallelogram is designed so as to be laid out in such a manner. In the figure, the two discharge ports 13 on the P line are laid out at the same position in the Y direction.

[0066] According to such a configuration, even if the two recording element substrates 10 are connected with a slight deviation during the manufacture of the liquid discharge head, the image at the position corresponding to the connection portion can be recorded by the plurality of discharge ports included in the overlap region. Therefore, in the image recorded on the paper surface, the black streaks and white spots due to the above deviation can be made less conspicuous. In the above description, the main plane of the recording element substrate 10 is a parallelogram, but the present invention is not limited to this. For example, a rectangular, trapezoidal, or other shaped recording element substrate can also be used.

[0067] Although not shown in FIGS. 10 to 12, each recording element substrate 10 is divided into a plurality of areas, and a temperature sensor 301 and a sub-heater 302 are provided for each area. Then, the control unit 500 (see FIG. 2) performs temperature adjustment based on the temperature set for each area using these temperature sensor 301 and sub-heater 302. That is, the control unit 500 drives the sub-heater 302 only for the areas where the detected temperature of the temperature sensor 301 is below the target temperature. By setting the target temperature of the recording element substrate 10 to a relatively high temperature, the viscosity of the ink can be lowered, and the ejection operation and circulation can be suitably performed. Further, by performing such temperature control and suppressing the temperature variation of the plurality of recording element substrates 10 within a predetermined range, the variation in the ejection amount due to the temperature variation between the recording element substrates 10 can be reduced, and density unevenness in the recorded image can be suppressed.

[0068] The target temperature of the recording element substrate 10 is preferably set to a temperature equal to or higher than the equilibrium temperature of the recording element substrate 10 when all the recording elements 15 are driven at the highest driving frequency assumed. As the temperature sensor 301, a diode sensor is applicable.

[0069] Note that as the heating means for the recording element substrate 10, the recording element 15 which is a heating element can also be used. Specifically, the recording element substrate 10 may be heated by applying a voltage to the recording element 15 that does not cause foaming. In the present embodiment, the recording element 15 may be employed instead of the sub-heater 302 as the heating means, or the sub-heater 302 and the recording element 15 may be used in combination.

[0070] <Another example of the recording head> FIGS. 13(a) and (b) are diagrams for explaining another example of the recording head 3 that can be used in the present embodiment. FIG. 13(a) is an external perspective view of the recording head 3, and FIG. 13(b) is an exploded view. Hereinafter, differences from the recording head 3 described with reference to FIGS. 4 and 5 will be described.

[0071] In the recording head 3 of this example, 36 ejection modules 200 are arranged in the Y direction and can accommodate a recording medium of size B2. That is, the recording head 3 of this example is longer than the recording head 3 described with reference to FIGS. 4 and 5. Hereinafter, the differences from the recording head 3 described with reference to FIGS. 4 and 5 will be described.

[0072] In the recording head 3 of this example, an electric wiring board support portion 82 extending in the Y direction is disposed at the center in the ±X direction. On both sides in the ±X direction of the electric wiring board support portion 82, four electric wiring boards 90 are arranged so as to be continuous in the Y direction and are supported by the electric wiring board support portion 82. Each of the electric wiring boards 90 is provided with a signal input terminal 91 and a power supply terminal 92. A shield plate 132 is provided outside the electric wiring boards 90 in the ±X direction to protect the wiring circuits of the electric wiring boards 90, the flexible wiring board 40, and their connection portions. In the exploded view of FIG. 13(b), the shield plate 132 is shown omitted.

[0073] In the recording head 3 of this example, the first negative pressure control unit 230 and the second negative pressure control unit 231 are provided on the lower side (-Z direction side) of the liquid supply unit 220 and do not protrude upward with respect to each of the recording head support portions 80.

[0074] FIGS. 14(a) to 14(c) are diagrams showing in detail the flow path structure of the recording head 3 of this example. FIG. 14(a) is a side sectional view of the recording head 3. Compared with the configuration described with reference to FIG. 4, the distances in the gravitational direction (Z direction) between the first negative pressure control unit 230 and the second negative pressure control unit 231 and the recording element substrate 10 are small. For this reason, the number of flow path connection portions is reduced as compared with the configuration described with reference to FIG. 4, the number of parts and the number of assembly steps can be reduced, and ink leakage can be suppressed.

[0075] In addition, the head difference between the first negative pressure control unit 230 and the second negative pressure control unit 231 and the discharge module 200 becomes smaller than the configuration described with reference to FIG. 4. Therefore, the recording apparatus 1000 can be particularly preferably employed in the form shown in FIG. 1(b), that is, a form in which a plurality of recording heads are arranged at different inclinations. Further, since the head difference becomes smaller, the flow resistance in the circulation channel decreases, the difference in pressure loss accompanying the change in flow rate becomes smaller, and stable negative pressure control can be performed.

[0076] FIG. 14(b) is a schematic diagram showing the state of ink circulation in the recording head 3 of this example. The ink circulation of this example is basically the same as the circulation described with reference to FIG. 3(b). That is, the pressure of the ink flowing into the discharge unit 300 is controlled by the first negative pressure control unit 230 and the second negative pressure control unit 231 that function as back pressure regulators arranged downstream thereof.

[0077] FIG. 14(c) is a cross-sectional view taken along the line XIVc-XIVc of FIG. 14(a). The discharge unit 300 of this example is also laminated with the second flow path member 60, the first flow path member 50, and the discharge module 200 in this order, similar to the discharge unit 300 described with reference to FIG. 8(b). However, in the discharge unit 300 of FIG. 8(b), the support member 30 is interposed between the first flow path member 50 and the recording element substrate 10, whereas in the discharge unit 300 of this example, the cover plate 20 (see FIG. 11) of the recording element substrate 10 is directly mounted on the surface of the first flow path member 50.

[0078] The individual supply channels 213a and the individual recovery channels 213b formed in each of the plurality of individual members 52 constituting the first flow path member 50 communicate with the openings 21 (see FIG. 10(c)) of the cover plate 20 disposed on the back surface of the recording element substrate 10. In the discharge unit 300 of this example, the individual communication ports 53 of the first flow path member 50 are openings sufficiently large with respect to the communication ports 61 of the second flow path member 60. For this reason, the alignment when mounting the first flow path member 50 on the second flow path member 60 becomes easier than the configuration described with reference to FIGS. 4(a) to 8(b), and as a result, the yield during manufacturing of the recording head can be improved.

[0079] In the recording apparatus 1000 of the present embodiment, either the recording head described with reference to FIGS. 4 to 8 or the recording head 3 described with reference to FIGS. 13 to 14 can be preferably used.

[0080] <Recording position deviation due to thermal expansion of the recording head> As already described, a plurality of temperature sensors 301 and sub heaters 302 are arranged on each recording element substrate 10 of the recording head 3 of the present embodiment, and during the recording operation, the recording element substrate 10 is adjusted to an appropriate temperature. Hereinafter, the process of adjusting the temperature of the recording head 3 prior to the recording operation is referred to as a temperature adjustment process. When the temperature adjustment process is performed, the ink heated by the recording element substrate 10 flows in the longitudinal direction (±Y direction) in the common recovery channel 212. As a result, the second channel member 60 is heated and tends to thermally expand in the longitudinal direction. And such a degree of thermal expansion becomes larger as the heating temperature by the sub heater 302 is higher and as the circulation amount of the ink passing through the recording element substrate 10 is larger.

[0081] On the other hand, the temperature sensors 301 and the sub heaters 302 include a certain degree of variation. Further, the circulation amount of the ink passing through the recording element substrate 10 depends on the pressure difference created by the first and second negative pressure control units 230 and 231, the flow resistance of the recording element substrate 10, the viscosity of the ink, etc., but it is difficult to make these tolerances and variations zero. That is, in the plurality of recording heads 3 mounted on the recording apparatus 1000, a certain degree of variation inevitably occurs in the degree of thermal expansion during the temperature adjustment process and the recording operation.

[0082] For example, a recording head in which the detected temperature of the temperature sensor 301 is detected higher than the actual temperature and the sub heater 302 is driven weakly becomes a recording head with small thermal expansion. Also, in a recording head with a small pressure difference created by the two negative pressure control units 230 and 231 or a recording head that discharges ink with a higher viscosity than others, the ink circulation amount of the recording element substrate 10 is relatively small, and it becomes a recording head with smaller thermal expansion compared to others.

[0083] Conversely, a recording head in which the detected temperature of the temperature sensor 301 is detected lower than the actual temperature and the sub-heater 302 is driven more strongly will be a recording head with a large thermal expansion. Also, in a recording head where the pressure difference created by the two negative pressure control units 230 and 231 is large, or a recording head that discharges ink with a lower viscosity than others, the ink circulation amount of the recording element substrate 10 is relatively large, and it becomes a recording head with a larger thermal expansion compared to others.

[0084] FIG. 15 is a diagram for explaining the recording position shift due to the thermal expansion of the recording head 3. Here, the carriage 70 is not shown, but the recording head 3 mounted on the carriage 70 via the connecting portion 72 is shown. When the recording head 3 thermally expands, the side of the movable portion 71 of the carriage 70 moves in the +Y direction, while the other side hardly moves (see FIG. 6). Hereinafter, for convenience of explanation, the +Y direction is referred to as the movable side, and the opposite -Y direction is referred to as the fixed side. In FIG. 15, among the plurality of recording heads 3 mounted on the recording apparatus 1000, the recording head 3 with a small thermal expansion in the longitudinal direction is shown as head A, and the recording head 3 with a large thermal expansion is shown as head B.

[0085] When temperature control is not performed and no thermal expansion occurs, the sizes of both head A and head B in the Y direction are almost the same. That is, the positions of the ends of the recording area in the Y direction are almost the same for head A and head B.

[0086] When thermal expansion occurs, for both head A and head B, the position of the connecting portion 72 on the fixed side does not change, and the connecting portion 72 on the movable side moves in the +Y direction. That is, all the recording element substrates 10 are displaced toward the movable side compared to before expansion, and the amount of displacement is larger for the recording element substrate 10 located in the +Y direction. And the amount of displacement of each recording element substrate 10 is larger for head B with a large thermal expansion than for head A with a small thermal expansion.

[0087] In the figure, the recording position Xb1 at the fixed-side outermost end of head B is slightly shifted in the +Y direction from the recording position Xa1 at the fixed-side outermost end of head A. Also, the recording position Xb2 at the movable-side outermost end of head B is shifted in the +Y direction from the recording position Xa2 at the movable-side outermost end of head A. And the amount of shift (Xb2 - Xa2) at the movable-side end is larger than the amount of shift (Xb1 - Xa1) at the fixed-side end.

[0088] Also, even in the same recording head, the above shift amount changes according to the ejection frequency. The higher the ejection frequency, the more the heated ink is discharged to the outside and the circulation amount of the ink decreases, so the expansion amount in the Y direction is suppressed to be small.

[0089] Figure 16 is a diagram comparing the recording areas in the Y direction of the above head A and head B in the maximum drive state and the minimum drive state. Hereinafter, for convenience of explanation, a state in which all the recording elements 15 are driven at the maximum drive frequency to eject a large amount of ink is called the maximum drive state. Also, a state in which non-ejection or ejection to the extent that it can be regarded as equivalent to non-ejection is called the minimum drive state.

[0090] As described above, since the expansion amount is suppressed to be smaller as the ejection frequency is higher, for both head A and head B, the recording area in the maximum drive state is narrower than the recording area in the minimum drive state. In the figure, the recording position of the movable-side end of head A in the minimum drive state is shown as Xa2, and the recording position of the movable-side end of head B in the minimum drive state is shown as Xb2. Also, the recording position of the movable-side outermost end of head A in the maximum drive state is shown as Xa3, and the recording position of the movable-side end of head B in the maximum drive state is shown as Xb3. In this case, a color shift of up to (Xb2 - Xa3) will occur between head A with small thermal expansion and head B with large thermal expansion. Such a recording position shift is on the order of several hundred micrometers at most, and there is concern about a decrease in image quality.

[0091] <Method for setting the usage area in the first embodiment> As already described, in the recording head 3 of the present embodiment, a plurality of recording element substrates 10 are arranged in the Y direction so as to include the width of the recording medium, that is, over a distance larger than the width of the recording medium. Therefore, the ejection port region in which a plurality of ejection ports arranged in the Y direction are arranged includes a used region actually used for recording and an unused region not used for recording. In the present embodiment, by devising such setting of the used region and the unused region for each recording head, the recording position shift due to thermal expansion between the plurality of recording heads 3 is suppressed to be small.

[0092] FIG. 17 is a flowchart for explaining the adjustment process of the recording position shift in the present embodiment. This process is executed by the control unit 500 according to a program stored in the ROM (see FIG. 2). In addition, this process is appropriately executed not only at the time of shipment of the recording apparatus 1000 but also when the recording head 3 is replaced or when the recording position shift becomes conspicuous.

[0093] When this process is started, the control unit 500 first performs temperature control on all the recording heads 3 under the same conditions in step S1. After the thermal expansion reaches a steady state, using all the ejection ports of each recording head 3, the test pattern read from the ROM 502 is recorded on the recording medium.

[0094] In step S2, the control unit 500 acquires the recording region of each recording head 3. Here, the recording region means information on the width in the Y direction and the position of the end of the image recorded using all the ejection ports. The acquisition of the recording region may be performed by the control unit 500 reading the test pattern using a reading sensor (not shown) provided in the apparatus, or may be performed by receiving the result measured by the user or the service technician.

[0095] In step S3, the control unit 500 sets the used region of each recording head 3. Here, the used region indicates the region occupied by the ejection ports 13 actually used for recording among the plurality of ejection ports 13 arranged in each recording head 3. When the used region of the ejection port 13 is determined, the used region of the recording element 15 driven for actual recording is determined.

[0096] FIG. 18 is a diagram for explaining a method of setting a usage area that the control unit 500 performs in step S3. First, the control unit 500 determines a reference head 3A serving as a reference among the plurality of recording heads 3. As the reference head 3A, for example, a recording head 3 that discharges black ink may be used. Heads other than the reference head 3A become adjustment target heads 3B for which a usage area is set with the reference head 3A as a reference. In FIG. 18, the reference head 3A and one adjustment target head 3B are shown in comparison.

[0097] Next, a usage area 172 of the reference head 3A is set. Specifically, based on the relative position in the Y direction between the recording area 171 of the reference head 3A and the recording medium, an area that can be recorded at an appropriate position with respect to the recording medium in the recording area 171 of the reference head 3A is set as the usage area 172. As a result, an area not included in the usage area 172 in the recording area 171 of the reference head 3A becomes a non-usage area 173.

[0098] Next, the center position O of the usage area 172 in the reference head 3A is obtained. Then, for the recording area 174 of the adjustment target head 3B, an area that is uniform in the ±Y direction and includes a predetermined number of nozzles is set as the usage area 175 from the same position as the center position O. As a result, an area not included in the usage area 175 in the recording area 174 of the adjustment target head 3B becomes a non-usage area 176.

[0099] FIG. 18 shows a case where the adjustment target head 3B has a larger amount of thermal expansion than the reference head 3A. The recording area 174 of the adjustment target head 3B with a large amount of thermal expansion expands more greatly on the movable side than on the fixed side with respect to the recording area 171 of the reference head. In the figure, the displacement amount on the fixed side between the recording area 171 of the reference head 3A and the recording area 174 of the adjustment target head 3B is shown as Δd1, and the displacement amount on the movable side is shown as Δd2 (>Δd1).

[0100] Regarding the use areas 172 of the reference head 3A and 175 of the head 3B to be adjusted, the displacement amount on the fixed side is shown as Δd3, and the displacement amount on the movable side is shown as Δd4. Here, focusing on the displacement amount on the movable side, it can be seen that the displacement amount Δd4 between the use areas 172 and 175 is suppressed to be smaller than the displacement amount Δd2 between the recording areas 171 and 174. This is because the use areas of the reference head 3A and the head 3B to be adjusted are determined so that their respective center positions O coincide, and the displacement of the recording positions between the reference head 3A and the head 3B to be adjusted due to thermal expansion is dispersed to the fixed side and the movable side. If the use area of the head 3B to be adjusted is determined based on the end on the fixed side or the movable side of the use area 172 of the reference head 3A, a larger displacement of the recording position than Δd4 will occur on the movable side. Such an effect can be obtained similarly even when the thermal expansion amount of the head 3B to be adjusted is smaller than that of the reference head 3A. In step S3 of FIG. 17, the use areas of all the heads 3B to be adjusted are determined by the above method.

[0101] Return to the flowchart of FIG. 17. In step S4, the control unit 500 stores the use area of each recording head 3 determined in step S3 in the memory. The memory may be the ROM 501, or may be a storage means provided separately from the ROM 501. This ends this process.

[0102] Thereafter, when a recording command is input to the recording apparatus 1000, the control unit 500 reads out the use area of each recording head 3 stored in the above memory. Then, using the said use area, an image is recorded on the recording medium according to the image data. Thereby, a high-quality image without color misregistration can be recorded on the recording medium S.

[0103] As described above, according to the present embodiment, the use areas of the reference head 3A and the head 3B to be adjusted are determined based on the center position in the Y direction. Thereby, the displacement of the recording positions between the reference head 3A and the head 3B to be adjusted can be suppressed to be small, and the color misregistration on the image can be made less noticeable.

[0104] Note that the setting of the usage area for each recording head described above is preferably performed for each size of the recording medium that the recording apparatus 1000 can handle, and is stored for each size of the recording medium.

[0105] (Second Embodiment) Also in this embodiment, as in the first embodiment, the recording apparatus 1000 and the recording head 3 described with reference to FIGS. 1 to 14 are used. However, in this embodiment, the usage area of the adjustment target head 3B is set in consideration of the expansion difference due to the difference in ejection frequency described with reference to FIG. 16.

[0106] FIG. 19 shows a case where the usage area of the reference head 3A and the usage area of the adjustment target head 3B are set by the method of the first embodiment using the same reference head 3A and adjustment target head 3B as in FIG. 18.

[0107] If both the reference head 3A and the adjustment target head 3B are in the maximum drive state, the recording position shift on the movable side is Δd5, and if both the reference head 3A and the adjustment target head 3B are in the minimum drive state, the recording position shift on the movable side is Δd6. Such a recording position shift amount is the result of being distributed between the fixed side and the movable side, and is suppressed to a relatively small value. However, depending on the image to be recorded, the reference head 3A may be in the maximum drive state and the adjustment target head 3B may be in the minimum drive state. In such a case, the recording position shift Δd7 on the movable side becomes even larger than Δd5 and Δd6. In view of the above, in this embodiment, the recording position shift is further reduced in consideration of the expansion due to the difference in the drive state, that is, the ejection frequency.

[0108] Also in this embodiment, the adjustment process is performed according to the flowchart described with reference to FIG. 17. However, in step S1 of this embodiment, for each recording head 3, a test pattern is recorded in each of the maximum drive state and the minimum drive state. Then, in step S2, based on these test patterns, the minimum recording area in the maximum drive state and the maximum recording area in the minimum drive state are acquired.

[0109] Specifically, each recording element substrate 10 is heated to the temperature control temperature for normal recording operation, and while performing predetermined circulation control, all recording elements are driven at the maximum driving frequency. Then, after the thermal expansion reaches a steady state, a test pattern is recorded, and the recording area in the Y direction of the image is acquired as the minimum recording area. Similarly, under the same conditions as above, a plurality of recording elements are driven at the lowest driving frequency at which the recording area can be confirmed. Then, after the thermal expansion reaches a steady state, a test pattern is recorded, and the recording area in the Y direction of the image is acquired as the maximum recording area.

[0110] FIGS. 20(a) and (b) are diagrams for explaining a method of setting a use area performed by the control unit 500 in step S3 of the present embodiment. FIG. 20(a) shows a case where the amount of thermal expansion of the adjustment target head 3B is larger than that of the reference head 3A, and FIG. 20(b) shows a case where the amount of thermal expansion of the adjustment target head 3B is smaller than that of the reference head 3A. Also in the present embodiment, first, for the recording area 171 of the reference head 3A, the use area 172 and the non-use area 173 are set from the relative position with the sheet.

[0111] In the case of FIG. 20(a), the maximum deviation amount between the reference head 3A and the adjustment target head 3B is on the movable side when the reference head 3A is in the maximum driving state and the adjustment target head 3B is in the minimum driving state. In this case, first, the deviation amount Δd8 between the end on the movable side of the minimum recording area of the reference head 3A and the end on the movable side of the maximum recording area of the adjustment target head 3B is obtained. Here, in FIG. 20, the non-use area 173 is enlarged for explanation, but the actual non-use area 173 is sufficiently small compared to the entire discharge port area. Therefore, the deviation amount Δd8 measured using all the discharge ports can be regarded as the sum of the deviation amounts of the use areas of the adjustment target head 3B and the reference head 3A.

[0112] Next, the movable-side end R2 of the use area 175 in the minimum drive state of the adjustment target head 3B is set so that the deviation amount between the movable-side end R1 of the use area 172 in the maximum drive state of the reference head 3A and the movable-side end R2 of the use area 175 in the minimum drive state of the adjustment target head 3B becomes Δd8 / 2. Then, with this movable-side end R2 as a reference, the fixed-side end R2', that is, the use area 175 of the adjustment target head 3B is set. As described above, on both the fixed side and the movable side, the recording position deviation regarding the use areas of the reference head 3A and the adjustment target head 3B can be suppressed to an amount smaller than Δd8 / 2 regardless of the ejection frequency of these recording heads.

[0113] Note that the use area 175 of the adjustment target head 3B can also be set with reference to the fixed side. That is, the fixed-side end of the use area 175 may be set so that the deviation amount between the fixed-side end R1' in the minimum drive state of the use area 172 of the reference head 3A and the fixed-side end R2' in the minimum drive state (or maximum drive state) of the use area 175 of the adjustment target head 3B becomes Δd8 / 2. In this case, with this fixed-side end as a reference, the movable-side end, that is, the use area 175 of the adjustment target head 3B may be set. In either case, the same effect can be obtained.

[0114] On the other hand, in the case of Fig. 20(b) where the amount of thermal expansion of the adjustment target head 3B is smaller than that of the reference head 3A, the deviation amount between the reference head 3A and the adjustment target head 3B becomes maximum when the reference head 3A is in the minimum drive state and the adjustment target head 3B is in the maximum drive state. In this case, the deviation amount Δd9 between the movable-side end of the maximum recording area of the reference head 3A and the movable-side end of the minimum recording area of the adjustment target head 3B is obtained. Next, the movable-side end of the use area 175 of the adjustment target head 3B is set so that the deviation between the movable-side end R3 of the use area 172 in the minimum drive state of the reference head 3A and the movable-side end R4 of the use area 175 in the maximum drive state of the adjustment target head 3B becomes Δd9 / 2. Then, with this movable-side end as a reference, the fixed-side end, that is, the use area 175 of the adjustment target head 3B is set. Note that also in the case of Fig. 20(b), the use area of the adjustment target head 3B can be set with reference to the fixed side.

[0115] Return to the flowchart of FIG. 17. In step S3, the use areas of all the heads 3B to be adjusted are determined by the above method. Thereafter, in step S4, the control unit 500 stores the use areas of the respective recording heads 3 determined in step S3 in the memory. This concludes this process.

[0116] Thereafter, when a recording command is input to the recording apparatus 1000, the control unit 500 uses the use areas of the respective recording heads 3 stored in the memory and records an image on the recording medium according to the image data. As a result, regardless of the ejection frequencies of the reference head 3A and the head 3B to be adjusted, the recording position shift between the two can be suppressed to an amount smaller than Δd9 / 2 both on the fixed side and on the movable side, and color misregistration on the image can be made inconspicuous.

[0117] (Third Embodiment) In the second embodiment, the maximum recording area and the minimum recording area were actually measured for each recording head 3. However, such actual measurement requires continuous temperature control processing and ejection operations until the state of thermal expansion stabilizes for each recording head, consuming a great deal of time and ink.

[0118] Therefore, in the present embodiment, for each recording head 3, the recording area in a state where thermal expansion intermediate between the maximum driving state and the minimum driving state is obtained is actually measured, and the use area of the head 3B to be adjusted is set based on the recording area. Specifically, while the drive of the recording head 3 is set to the minimum drive state, intermediate thermal expansion is reproduced by adjusting the recording element substrate 10 to a temperature lower than the set temperature (65° C.) in the normal recording operation. Hereinafter, a state where thermal expansion intermediate between the maximum driving state and the minimum driving state is obtained is referred to as an intermediate state.

[0119] <Method for reproducing intermediate state> FIG. 21 is a diagram showing the relationship between the circulation amount Vs and the temperature control temperature Ts for reproducing the intermediate state. In the following description, in the recording head 3, the total amount of ink flowing through the plurality of recording element substrates 10 arranged in the Y direction per unit time is referred to as the circulation amount Vs. Further, the target temperature that is commonly set for the plurality of recording element substrates 10 arranged in the Y direction and is adjusted by the temperature sensor 301 and the sub-heater 302 (see FIG. 2) is referred to as the temperature control temperature Ts. In general recording operations, the temperature control temperature is set to 65°C.

[0120] In FIG. 21, the relationship between the circulation amount Vs and the temperature control temperature Ts capable of reproducing the intermediate expansion amount is plotted. Such a relationship can be obtained by a thermal fluid structure coupling simulation and can be approximated by a cubic function having a minimum value α and a maximum value β. In the present embodiment, the ink temperature Ti flowing through the recording apparatus 1000 is controlled between 28°C and 32°C by a heat exchanger, and the cases where the ink temperature T is 28°C and 32°C are shown as legends in the figure.

[0121] Here, the cubic function Ts(Vs) of the temperature control temperature Ts can be expressed by the following general formula using the coefficients a, b, c, and d.

[0122]

Equation

[0123] However, in the case of (Equation 1), the coefficients a, b, c, and d also change according to the ink temperature Ti, but the values of the coefficients a, b, c, and d corresponding to an arbitrary ink temperature Ti cannot be linearly obtained from the cases where the ink temperature Ti is 28°C and 32°C. Therefore, in the present embodiment, the following (Equation 2) using the minimum value α and the maximum value β is used as the cubic function Ts(Vs) of the temperature control temperature Ts.

[0124]

Equation

[0125] Using equation (2), the values of the coefficients a, α, and β corresponding to any ink temperature Ti can be linearly determined from the cases where the ink temperature T is 28°C and 32°C. Note that the coefficients a, α, and β when the ink temperature T is 28°C and 32°C are obtained in advance by simulation.

[0126] In this embodiment, for any ink temperature Ti between 28°C and 32°C, it is assumed that the coefficients a, α, and β can be calculated using the following equation (3).

[0127] [Equation]

[0128] That is, in this embodiment, the cubic function of any recording head 3 can be derived by measuring the ink temperature Ti circulating through the recording apparatus 1000 via the recording head 3. Then, by using the derived cubic function, the temperature control temperature Ts for reproducing the intermediate expansion amount in the recording head 3 can be obtained based on the circulation amount Vs of the recording element substrate 10.

[0129] Next, a method for measuring the circulation amount Vs will be described.

[0130] Figs. 22(a) to (c) are diagrams for explaining the relationship between the circulation amount Vs and the ink flow rate in the discharge unit 300.

[0131] Fig. 22(a) is a diagram schematically showing the circulation of ink. A first negative pressure control unit 230 that generates a relatively high pressure is connected to the common supply channel 211, and a second negative pressure control unit 231 that generates a relatively low pressure is connected to the common recovery channel 212. Therefore, a flow from the common supply channel 211 toward the common recovery channel 212 is generated in the recording element substrate 10, and the total flow rate passing through the plurality of recording element substrates 10 becomes the circulation amount Vs. The circulation amount Vs is controlled based on tolerances such as the differential pressure created by the first and second negative pressure control units 230 and 231, the liquid viscosity, and the flow path resistance, and is adjusted to 25 to 255 ml / min in this embodiment.

[0132] In this embodiment, when the ejection operation is performed on each recording element substrate 10, it is assumed that ink is supplied to the recording element substrate 10 from the common supply channel 211 and the common recovery channel 212 at a ratio of approximately 6:4. Also, the consumption amount of ink accompanying the ejection operation is set to 0 to 308 ml / min. Note that this maximum value of 308 ml / min is an average value considering the instantaneous substantial consumption amount of 375 ml / min when driving at the highest driving frequency and the non-ejection period at the time of page switching. However, these numerical values can be appropriately changed according to the flow path shape and the like.

[0133] Figs. 22(b) and (c) respectively show the relationship between the circulation amount Vs and the upstream flow rate Q1 of the common supply channel 211 and the relationship between the circulation amount Vs and the upstream flow rate Q2 of the common recovery channel 212.

[0134] The relationship between the upstream flow rates Q1 and Q2 and the circulation amount Vs can be measured by installing flow meters at a total of four locations, upstream and downstream, of the common supply channel 211 and the common recovery channel 212. Specifically, the difference between the measured values of the two flow meters provided upstream and downstream of the common supply channel 211, that is, the difference between the upstream flow rate and the downstream flow rate, is defined as the circulation amount Vs. Similarly, the difference between the measured values of the two flow meters provided upstream and downstream of the common recovery channel 212 can also be defined as the circulation amount Vs. Alternatively, the average value of these two types of differences may be defined as the circulation amount Vs.

[0135] In FIGS. 22(b) and (c), the minimum required flow rate determined by the amount of ink that may be consumed by the recording element substrate 10, the maximum allowable flow rate determined by the conditions for the normal operation of the negative pressure control unit, and the set flow rate of the present embodiment are shown as a legend. All of them have a linear relationship with the circulation amount Vs. That is, in the recording head 3 of the present embodiment, while checking the measured value of the flow meter, by controlling the first to third circulation pumps P1 to P3 described with reference to FIG. 3, the circulation amount Vs of the recording element substrate 10 can be adjusted. Further, based on the graphs of FIGS. 22(b) and (c), the circulation amount Vs of the recording head 3 can be obtained from the measured values of the upstream flow rate Q1 of the common supply channel 211 and the upstream flow rate Q2 of the common recovery channel 212 of the target recording head 3.

[0136] That is, in the present embodiment, the intermediate state of any recording head 3 can be reproduced by the following procedure. First, the ink temperature Ti and the circulation amount Vs of the target recording head 3 are measured. At this time, for the circulation amount Vs, the upstream flow rate Q1 of the common supply channel 211 and the upstream flow rate Q2 of the common recovery channel 212 are actually measured and obtained based on the graphs of FIGS. 22(b) and (c). Next, using the measured ink temperature Ti, a cubic function of the target recording head 3 is derived according to (Equation 2) and (Equation 3). Then, according to the derived cubic function, the temperature control temperature Ts corresponding to the circulation amount Vs is obtained (see FIG. 21). Finally, the temperature of each recording element substrate 10 of the target recording head 3 is adjusted to the temperature control temperature Ts and waiting for it to reach a steady state. Thereby, in the target recording head 3, an intermediate state of thermal expansion between the maximum drive state and the minimum drive state can be reproduced.

[0137] <Usage area setting method> Also in the present embodiment, adjustment processing is performed according to the flowchart described with reference to FIG. 17. However, in step S1 of the present embodiment, a test pattern is recorded in the intermediate state for each recording head 3, and in step S2, the recording area is obtained from the test pattern.

[0138] Figs. 23(a) and (b) are diagrams for explaining the method of setting the usage area that the control unit 500 performs in step S3 of the present embodiment. Here, a case where the thermal expansion amount of the head 3B to be adjusted is larger than that of the reference head 3A is shown.

[0139] Fig. 23(a) is a diagram for comparing the entire ejection port area before setting the usage area between the reference head 3A and the head 3B to be adjusted. In the figure, the deviation amount between the movable-side end of the recording area of the reference head 3A and the movable-side end of the recording area of the head 3B to be adjusted in the intermediate state is indicated by Δd0. Also, in the recording area of the reference head 3A, the deviation amount between the movable-side end in the maximum drive state and the movable-side end in the intermediate state, and the deviation amount between the movable-side end in the intermediate state and the movable-side end in the minimum drive state are indicated by Δdr. Further, in the recording area of the head 3B to be adjusted, the deviation amount between the movable-side end in the maximum drive state and the movable-side end in the intermediate state, and the deviation amount between the movable-side end in the intermediate state and the movable-side end in the minimum drive state are indicated by Δdt. As already described, the intermediate state is a state in which thermal expansion intermediate between the maximum drive state and the minimum drive state is obtained. Therefore, the deviation amount between the maximum ejection and the intermediate state, and the deviation amount between the intermediate state and the substantially non-ejection state are equal values.

[0140] Here, the deviation amount Δd0 is a value that can be actually measured in a state where the reference head 3A and the head 3B to be adjusted are stabilized in thermal expansion in their respective intermediate states. On the other hand, the deviation amounts Δdr and Δdt are values obtained from the graph of Fig. 24 acquired by simulation.

[0141] Fig. 24 is a diagram showing the relationship between the circulation amount Vs of the recording element substrate 10 in the recording head 3 and the expansion amount Δd. Such a relationship can be obtained in advance by calculating or actually measuring it by a thermal fluid structure coupling simulation under the above-described predetermined circulation control. In Fig. 24, cases where the ink temperature Ti is 28°C and 32°C are plotted. That is, by using this graph, the deviation amount Δdr of the reference head 3A can be derived from the circulation amount Vs and the ink temperature Ti of the reference head 3A, and the deviation amount Δdt of the head 3B to be adjusted can be derived from the circulation amount Vs and the ink temperature Ti of the head 3B to be adjusted.

[0142] As shown in Fig. 23(a), when the thermal expansion amount of the head 3B to be adjusted is larger than that of the reference head 3A, the recording position deviation becomes maximum when the reference head 3A is in the maximum driving state and the head 3B to be adjusted is in the minimum driving state. And the maximum deviation amount Δdmax can be expressed by (Equation 4).

[0143]

Equation

[0144] Fig. 23(b) is a diagram for explaining a method of setting the use areas of the reference head 3A and the head 3B to be adjusted. Regarding the use area 172 of the reference head 3A, similar to the above embodiment, it is set at an appropriate position with respect to the recording medium in the recording area 171 of the reference head 3A. And when the above maximum recording position deviation amount Δdmax occurs, the use area 175 of the head 3B to be adjusted is set so that this deviation amount is equally divided between the fixed side and the movable side.

[0145] That is, the movable side end R6 of the use area 175 of the head 3B to be adjusted is determined so that the deviation amount between the movable side end R5 of the use area 172 of the reference head 3A in the maximum driving state and the movable side end R6 of the use area 175 of the head 3B to be adjusted in the minimum driving state becomes Δdmax / 2. And with this movable side end as a reference, the fixed side end, that is, the use area 175 of the head 3B to be adjusted is set.

[0146] Also, the use area of the head 3B to be adjusted can be set with the fixed side as a reference. That is, the deviation amount between the fixed side end R5' of the use area 172 of the reference head 3A in the minimum driving state and the fixed side end R6' of the use area 175 of the head 3B to be adjusted in the maximum driving state is made Δdmax / 2. That is, the fixed side end of the use area 175 of the head 3B to be adjusted is determined in that way. And with this fixed side end as a reference, the movable side end, that is, the use area 175 of the head 3B to be adjusted may be set.

[0147] However, in this embodiment, only the end positions of the movable side and the fixed side in the intermediate state can be confirmed for the actual position, and the positions of R5, R6, R5', and R6' cannot be confirmed. Therefore, the use area 175 of the adjustment target head 3B is determined based on the end positions of the movable side and the fixed side in the intermediate state.

[0148] Figs. 25(a) and (b) are enlarged views for explaining a method of setting the use area of the adjustment target head 3B based on the use area 172 of the reference head 3A in the intermediate state. Fig. 25(a) shows a state of setting the end of the movable side of the use area 175 of the adjustment target head 3B with reference to the end of the movable side of the use area 172 of the reference head 3A.

[0149] As shown in Fig. 25(a), in the intermediate state, the end R8 of the movable side of the use area 175 of the adjustment target head 3B may be set at a position offset by Δds to the movable side from the end R7 of the movable side of the use area of the reference head 3A. The offset amount Δds can be obtained by (Equation 5). Δds = Δdmax / 2 - Δdr - Δdt =(Δd0 + Δdr + Δdt) / 2 - Δdr - Δdt (Equation 5) =(Δd0 - Δdr - Δdt) / 2

[0150] Also, the use area of the adjustment target head 3B can be set with reference to the fixed side. Fig. 25(b) shows a state of setting the end of the fixed side of the use area 175 of the adjustment target head 3B with reference to the end of the fixed side of the use area 172 of the reference head 3A. On the fixed side, the recording position shift due to thermal expansion can be almost ignored. Therefore, in this case, in the intermediate state, the end R10 of the fixed side of the use area 175 of the adjustment target head 3B may be set at a position offset by Δdmax / 2 = (Δd0 + Δdr + Δdt) / 2 to the fixed side from the end R9 of the fixed side of the use area 172 of the reference head 3A.

[0151] FIG. 26(a) and (b) are diagrams for explaining a method of setting a use area when the amount of thermal expansion of the head 3B to be adjusted is smaller than that of the reference head 3A. The methods for obtaining Δd0, Δdr, Δdt, Δdmax, and Δds are the same as those in FIGS. 23(a) and (b), but the offset direction is opposite. That is, when the movable side is used as a reference, in the intermediate state, the movable-side end of the use area 175 of the head 3B to be adjusted may be set at a position offset by Δds toward the fixed side from the movable-side end of the use area 172 of the reference head 3A. Also, when the fixed side is used as a reference, in the intermediate state, the fixed-side end of the use area 175 of the head 3B to be adjusted may be set at a position shifted by Δdmax / 2 = (Δd0 + Δdr + Δdt) / 2 toward the movable side from the fixed-side end of the use area 172 of the reference head 3A.

[0152] Return to the flowchart of FIG. 17. In step S3, the use areas of all the heads 3B to be adjusted are determined by the above method. Then, in step S4, the control unit 500 stores the use areas of the respective recording heads 3 determined in step S3 in the memory. This completes the present process.

[0153] Thereafter, when a recording command is input to the recording apparatus 1000, the control unit 500 uses the use areas of the respective recording heads 3 stored in the memory and records an image on the recording medium according to the image data.

[0154] According to the present embodiment described above, without measuring the maximum recording area and the minimum recording area as in the second embodiment, by measuring only the recording area in the intermediate state, the same effect as in the second embodiment can be obtained. That is, the recording position shift between the reference head 3A and the head 3B to be adjusted can be made inconspicuous on the image regardless of the ejection frequency of these recording heads.

[0155] Incidentally, in the above description, with reference to FIG. 21, the case where the temperature control temperature Ts is approximated by a cubic function of the circulation rate Vs has been described. However, depending on the underlying circulation control, such a function may preferably be approximated by a function different from a cubic function. In any case, as long as an approximation function is obtained such that the temperature control temperature Ts is determined with respect to the circulation rate Vs based on the relationship obtained by simulation or actual measurement, any function may be used.

[0156] Also, in FIGS. 22(b) and (c), the case where the upstream flow rate Q1 of the common supply channel 211 and the upstream flow rate Q2 of the common recovery channel 212 continuously change with respect to the circulation rate Vs has been described. However, in the present embodiment, such continuity is not an essential requirement. When the upstream flow rate Q1 of the common supply channel 211 or the upstream flow rate Q2 of the common recovery channel 212 discontinuously changes with respect to the circulation rate Vs, it may be expressed by a plurality of functions that are not continuous with each other. In any case, it is sufficient that the circulation rate Vs is uniquely determined with respect to the measured Q1 and Q2.

[0157] Furthermore, in the above, after deriving the function of the temperature control temperature Ts and the circulation rate Vs as shown in FIG. 22 in association with the ink temperature Ti and obtaining the temperature control temperature Ts from the circulation rate Vs using the function, these procedures can be reversed. That is, a function of the temperature control temperature Ts and the ink temperature Ti may be derived in association with the circulation rate Vs, and the temperature control temperature Ts may be obtained from the ink temperature Ti using the function.

[0158] Moreover, in the above, the temperature control temperature Ts corresponding to the ink temperature Ti and the circulation rate Vs has been calculated using functional expressions such as (Equation 2) and (Equation 3), but the temperature control temperature Ts may also be obtained by referring to a look-up table. In this case, a three-dimensional look-up table in which the ink temperature Ti, the circulation rate Vs, and the temperature control temperature Ts are associated with each other may be prepared in advance. Such a look-up table can be created by actually measuring the relationship between the temperature control temperature Ts and the thermal expansion amount of the recording head 3 or by performing a thermal fluid structure coupling simulation.

[0159] Also, in the above description, an intermediate state in which intermediate thermal expansion is obtained by adjusting the temperature control temperature Ts has been reproduced. However, such an intermediate state can also be reproduced by adjusting the driving conditions, for example, by setting the driving frequency to approximately half of the maximum driving state. In any case, if an intermediate state in which substantially intermediate thermal expansion is obtained can be reproduced and the recording area can be actually measured, it becomes possible to set the usage area of the adjustment target head 3B by the method described with reference to FIGS. 25 and 26, and the effects of the present embodiment can be obtained.

[0160] (Other Embodiments) In the second and third embodiments, the maximum displacement amounts of the two recording heads were measured based on the maximum driving state in which all the recording elements are driven at the maximum driving frequency to eject ink and the minimum driving state in which the minimum ejection operation capable of confirming the recording width on the recording medium is performed. However, such maximum displacement amounts can also be obtained by conversion from the displacement amounts of the recording areas when driving at a relatively high driving frequency and when driving at a relatively low driving frequency, for example.

[0161] Also, in the above description, the case where the ink temperature Ti flowing through the recording apparatus 1000 is maintained at 28° C. to 32° C. by the heat exchanger and the temperature control temperature Ts of the recording element substrate 10 in the normal recording operation is set to 65° C. has been described as an example. However, such temperatures can also be changed. However, if the difference between the ink temperature Ti and the temperature control temperature Ts is too small, the difference in thermal expansion between the recording heads due to the temperature control process and the circulation control may not appear so significantly. In order to sufficiently exhibit the effects of the above-described embodiment, it is preferable that the temperature control temperature Ts in the recording operation is 10° C. or higher than the ink temperature Ti.

[0162] Also, in the above description, a full-line type inkjet recording apparatus equipped with four-color recording heads has been described as an example. However, the above-described method for adjusting the recording position can also be adopted in other types of recording apparatuses. For example, the recording apparatus 1000 may be configured to include five or more recording heads that eject five or more colors of ink, or may be configured to include two recording heads 3 that eject the same color of ink.

[0163] Also, in the above, with reference to FIGS. 4 and 5, a recording head capable of corresponding to A3 size and B2 size has been taken as an example, but the length of the recording head is not particularly limited. In addition, the recording head 3 does not necessarily have to be a line-type recording head mounted on the full-line type recording apparatus 1000. Even in a serial type recording apparatus 1000 that alternately repeats the recording scan of the recording head and the conveyance operation of conveying the recording medium in a direction intersecting the recording scan, if the mounted recording head 3 is long, it is also assumed that a recording position shift due to thermal expansion may occur. And even in such a case, by setting the use area of the ejection ports between the recording heads according to the above-described embodiment, the effect of correcting the recording position shift between the recording heads can be obtained. However, in order to obtain the effect of correcting the recording position shift due to thermal expansion, it is preferable that the recording head has a recording width of A3 size or more.

[0164] The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiment to a system or apparatus via a network or a storage medium, and causing one or more processors in a computer of the system or apparatus to read and execute the program. Further, it can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

Explanation of Reference Numerals

[0165] 13 Recording element 10 Recording element substrate 3A Reference head 3B Head to be adjusted 1000 Recording apparatus

Claims

1. A method for adjusting a printing position in a first direction of a first print head and a second print head, each of which includes a plurality of printing element substrates on which a plurality of printing elements are arranged continuously in a first direction, a temperature control device for controlling a temperature of the printing element substrates, and a circulation device for circulating a liquid through the printing element substrates, the first print head and the second print head thermally expanding in response to circulation of the liquid by the temperature control device and the circulation device, comprising: the first recording head and the second recording head are disposed in a second direction intersecting the first direction, and are mounted on a recording device such that one side of the first direction is a fixed side and the other side is a movable side that is displaced in response to thermal expansion; an acquisition step of performing temperature control for the first print head and the second print head under the same conditions by the temperature control means and the circulation means, and driving the plurality of print elements to eject liquid and print a test pattern on a print medium, thereby acquiring a first print area which is a print area of ​​the first print head in the first direction, and a second print area which is a print area of ​​the second print head; a setting step of setting a first use area to be used for actual recording among a plurality of recording elements arranged on the first recording head based on the first recording area, and setting a second use area to be used for actual recording among a plurality of recording elements arranged on the second recording head based on the first use area and the second recording area; 13. A method for adjusting a recording position, comprising:

2. In the setting step, the first use area is set based on a relative position in the first direction between the recording medium and the first recording area; 2 . The method for adjusting a print position according to claim 1 , wherein the second area of ​​use is set such that a center of the first area of ​​use and a center of the second area of ​​use in the first direction coincide with each other.

3. In the obtaining step, a first driving state in which the first recording area and the second recording area are driven under a first driving condition in which the recording elements of the first recording head and the second recording head are driven at a maximum driving frequency compatible with the first recording head and the second recording head, and a second driving state in which the first recording head and the second recording head are driven under a second driving condition different from the first driving condition in which the first recording area and the second recording area are driven at a minimum driving frequency that can be confirmed on a recording medium, the second driving state having a larger amount of thermal expansion than the first driving state; In the setting step, when the second recording area is larger than the first recording area, the second recording area is set so that an amount of deviation between the movable side end of the first recording area in the first driving state and the movable side end of the second recording area in the second driving state is half an amount of deviation between the movable side end of the first recording area in the first driving state and the movable side end of the second recording area in the second driving state; A method for adjusting a recording position as described in claim 1, wherein, when the second recording area is smaller than the first recording area, the second use area is set so that the amount of deviation between the movable side end of the first use area in the second driving state and the movable side end of the second use area in the first driving state is half the amount of deviation between the movable side end of the first recording area in the second driving state and the movable side end of the second recording area in the first driving state.

4. In the obtaining step, an intermediate state is reproduced in which an intermediate thermal expansion between a first driving state in which the first recording head and the second recording head are driven at a maximum driving frequency and a second driving state in which the first recording head and the second recording head are driven at a minimum driving frequency is obtained, and the first recording area and the second recording area are obtained in the intermediate state; In the setting step, when the second recording area is larger than the first recording area, the second used area is set based on a deviation amount Δd0 between the movable side end of the first recording area in the intermediate state and the movable side end of the second recording area in the second driving state so that a deviation amount between the movable side end of the first used area in the first driving state and the movable side end of the second used area in the second driving state is half a deviation amount between the movable side end of the first recording area in the first driving state and the movable side end of the second recording area in the second driving state; 2. The method for adjusting a recording position according to claim 1, wherein, when the second recording area is smaller than the first recording area, the second use area is set based on a deviation Δd0 between the movable side end of the first recording area in the intermediate state and the movable side end of the second recording area in the first driving state, so that the deviation between the movable side end of the first recording area in the second driving state and the movable side end of the second use area in the first driving state is half the deviation between the movable side end of the first recording area in the second driving state and the movable side end of the second recording area in the first driving state.

5. a measuring step of measuring a circulation amount of liquid in the plurality of recording element substrates for each of the first recording head and the second recording head; acquiring a deviation amount Δdr between the movable side end of the first recording area in the first driving state and the movable side end of the first recording area in the intermediate state, and an deviation amount Δdt between the movable side end of the second recording area in the first driving state and the movable side end of the second recording area in the intermediate state based on the circulation amount; Further comprising: The method for adjusting a recording position according to claim 4, wherein in the setting process, the second use area is set so that the amount of deviation between the movable side end of the first use area and the movable side end of the second use area in the intermediate state is (Δd0-Δdr-Δdt) / 2, or so that the amount of deviation between the fixed side end of the first use area opposite the movable side and the fixed side end of the second use area in the intermediate state is (Δd0+Δdr+Δdt) / 2.

6. the first print head and the second print head each include a common supply flow path for commonly supplying liquid to the plurality of print element substrates, and a common recovery flow path for commonly recovering liquid from the plurality of print element substrates; The printing position adjustment method according to claim 5 , wherein in the measurement step, the circulation amount is obtained based on at least one of the difference between the upstream flow rate and the downstream flow rate of the common supply flow path and the difference between the upstream flow rate and the downstream flow rate of the common recovery flow path.

7. 7. The method for adjusting a print position according to claim 4, wherein the intermediate state is reproduced by setting a target temperature of the temperature adjustment means to a predetermined temperature lower than a temperature set in a normal print operation.

8. The method for adjusting a printing position according to claim 7, wherein the specified temperature is derived based on a function or a lookup table showing a relationship between the specified temperature, the amount of ink circulated through the multiple printing element substrates, and the temperature of ink circulating through the printing device.

9. 7. The method for adjusting a print position according to claim 4, wherein the intermediate state is reproduced by driving the print elements of the first print head and the second print head at a drive frequency lower than a maximum drive frequency that the print elements can support.

10. 10. The method of adjusting a print position according to claim 1, wherein the first printhead and the second printhead are line-type printheads having a print width equal to or larger than A3 size in the first direction.

11. A method for adjusting a printing position according to any one of claims 1 to 10, wherein the first print head and the second print head cause film boiling in the liquid by applying a pulse voltage to the printing element, and eject the liquid by the growth energy of the generated bubbles.

12. The method of adjusting a print position according to claim 1 , wherein the first print head and the second print head eject inks of different colors.

13. A method for adjusting a printing position according to any one of claims 1 to 12, wherein the temperature of the printing element substrate adjusted by the temperature control means when performing a printing operation is 10°C or more higher than the temperature of the liquid before it is supplied to the first printing head and the second printing head.

14. 14. The method for adjusting a print position according to claim 1, further comprising the step of storing information about the first use area and the second use area set in the setting step in a storage means.

15. receiving image data; reading information on the first and second use areas from the storage means; a step of recording an image on a recording medium according to the image data, using the first use area of ​​the first recording head and the second use area of ​​the second recording head corresponding to the information read from the storage means; 15. The method of claim 14, further comprising:

16. a temperature control device for controlling a temperature of the recording element substrate; and a circulation device for circulating a liquid through the recording element substrate, the temperature control device controlling the temperature of the recording element substrate. The temperature control device and the circulation device circulate a liquid through the recording element substrate. The temperature control device and the circulation device are provided with a plurality of recording element substrates on which a plurality of recording elements are arranged continuously in a first direction, and a method for adjusting recording positions in the first direction of a reference head and a head to be adjusted, the reference head and head to be adjusted each being thermally expanded in response to circulation of the liquid by the temperature control device and the circulation device, the method comprising the steps of: setting a recordable area of ​​the recording area of ​​the reference head at a position corresponding to the recording medium as a first usable area based on a relative position in the first direction between the recording area of ​​the reference head and the recording medium, and determining a center position of the first usable area; A method for adjusting a recording position, comprising: setting, as a second use area, equal areas on both sides of the first direction, with the same position as the center position of the first use area as the center position in the recording area of ​​the head to be adjusted.

17. The reference head and the head to be adjusted are mounted on a recording device with one end being a fixed side and the other end being a movable side, When thermal expansion occurs, positional deviation occurs on both the fixed side and the movable side, 17. The method of adjusting a print position according to claim 16, wherein the amount of deviation on the movable side is greater than the amount of deviation on the fixed side.

18. 18. The method of adjusting a print position according to claim 1, wherein the method is performed for each size of a print medium.

19. 19. The method for adjusting the print position according to claim 1, wherein the method for adjusting the print position is performed at the time of shipment, when the print head is replaced, or when a print position deviation becomes noticeable.

20. A program for causing a computer to execute the method for adjusting a recording position according to any one of claims 1 to 19.

Images