Liquid dispensing device, liquid dispensing head, liquid dispensing head control device, and liquid dispensing head control method

Abstract

The circulating energy generation element is driven at a different frequency than the discharge energy generation element. [Solution] A liquid dispensing device comprising a liquid dispensing head and a control unit for controlling the liquid dispensing head, wherein the liquid dispensing head comprises a plurality of dispensing energy generating elements for dispensing liquid in a plurality of pressure chambers from a plurality of dispensing ports, a plurality of circulating energy generating elements for circulating the liquid in the plurality of pressure chambers inside the liquid dispensing head, and means for inputting a plurality of dispensing energy generating element selection signals, a plurality of dispensing time-division selection signals, and a circulating period control signal, wherein the liquid is circulated by driving the circulating energy generating elements selected by the circulating energy generating element selection signals and the circulating time-division selection signals, and the control unit comprises means for generating a circulating period control signal such that the period of the plurality of circulating time-division selection signals is the same as or longer than the period of the plurality of dispensing time-division selection signals.

Description

Technical Field

[0001] The present disclosure relates to a liquid ejection head for ejecting a liquid onto a recording medium, a liquid ejection apparatus including the liquid ejection head, a liquid ejection head control apparatus for controlling the liquid ejection head, and a liquid ejection head control method.

Background Art

[0002] For the purpose of discharging bubbles in a flow path and suppressing thickening of ink near a discharge port in a liquid ejection head (hereinafter also referred to as a "head"), a circulation type inkjet recording apparatus (simply also referred to as a "recording apparatus") that circulates ink is known. As a method (system) for circulating ink, a method using a pressure difference (hereinafter also referred to as a "differential pressure method") is well known. In the differential pressure method, by using a pressure adjustment mechanism or the like to control the pressure on the side (inlet side) that supplies ink to the discharge port to be higher than the pressure on the side (outlet side) that collects ink, ink is made to flow from the inlet side to the outlet side. At this time, in order to circulate the ink, it is necessary to return the ink that has flowed to the outlet side to the inlet side, and a circulation pump (simply also referred to as a "pump") is required as a mechanism for this. Note that there are some that circulate ink between the liquid ejection head and the main body by providing a pump outside the head, such as in the main body of the recording apparatus, and there are also some that circulate ink within the liquid ejection head by providing a pump inside the liquid ejection head. However, in such a circulation method using differential pressure, mechanisms such as a pressure adjustment mechanism and a pump are required, and the recording apparatus main body and the head tend to become large.

[0003] Therefore, an ink circulation method that does not use differential pressure has been studied. Specifically, a circulation flow path communicating with the discharge port is provided. Then, an energy generating element for ejecting ink (hereinafter also referred to as an "ejection energy generating element") and an energy generating element for circulating ink (hereinafter also referred to as a "circulation energy generating element") are arranged in the circulation flow path. By driving the circulation energy generating element, ink is circulated in the circulation path.

[0004] Patent Document 1 discloses a circuit configuration for selectively driving multiple discharge energy generating elements and multiple circulating energy generating elements provided on a recording element substrate. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Special Publication No. 2020-507497 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, in Patent Document 1, addresses are assigned to the ejection energy generating element and the circulation energy generating element so that they can be selected individually. When the inkjet recording device individually addresses each energy generating element with a different function and transmits data signals, a problem arises in that the amount of data increases depending on the number of energy generating elements. As a configuration to reduce the amount of data, a configuration can be considered in which the selection information of the circulation energy generating element is converted within the recording element substrate according to the selection information of the ejection energy generating element, and each circulation energy generating element is selected. In this case, since the ejection energy generating element and the circulation energy generating element are selected at the same drive frequency, a problem arises in that the circulation energy generating element cannot be driven at the optimal drive frequency for the circulation energy generating element. For example, if the drive frequency of the circulation energy generating element is the same as the drive frequency of the ejection energy generating element, and this drive frequency is faster than the optimal drive frequency for the circulation energy generating element, a problem arises in that ideal ink circulation cannot be achieved.

[0007] This disclosure aims to enable the circulating energy generation element to be driven at a different frequency than the discharge energy generation element. [Means for solving the problem]

[0008] One embodiment of the present disclosure is a liquid dispensing device comprising a liquid dispensing head for dispensing liquid onto a recording medium and a liquid dispensing head control unit for controlling the liquid dispensing head, wherein the liquid dispensing head comprises a plurality of outlets for dispensing liquid, a plurality of pressure chambers communicating with the plurality of outlets, a plurality of discharge energy generating elements that generate energy for dispensing the liquid in the plurality of pressure chambers from the plurality of outlets, a plurality of circulating energy generating elements that generate energy for circulating the liquid in the plurality of pressure chambers inside the liquid dispensing head, and means for inputting a plurality of discharge energy generating element selection signals, a plurality of discharge time division selection signals, and a circulating period control signal, wherein the liquid is circulated by driving the circulating energy generating elements selected by the circulating energy generating element selection signals and the circulating time division selection signals, and the liquid dispensing head control unit comprises generation means for generating the circulating period control signal such that the period of the plurality of circulating time division selection signals is the same as or longer than the period of the plurality of discharge time division selection signals. [Effects of the Invention]

[0009] According to this disclosure, the circulating energy generating element can be driven at a different frequency from the discharge energy generating element, while using at least some of the information for selecting the discharge energy generating element to select the circulating energy generating element. [Brief explanation of the drawing]

[0010] [Figure 1] A schematic perspective view of a liquid dispensing device. [Figure 2] A schematic diagram illustrating the area near the discharge port of the liquid discharge head in detail. [Figure 3] A perspective view showing the liquid dispensing head, and a plan view of the liquid dispensing tip. [Figure 4] Functional block diagram showing an example configuration of a liquid discharge head. [Figure 5] Functional block diagram showing the configuration of the liquid dispensing device. [Figure 6] Timing diagram for explaining the operation of the timing generation unit [Figure 7] Functional block diagram showing the configuration of the liquid ejection head control unit [Figure 8] Timing diagram showing the signals generated by the liquid ejection head control unit [Figure 9] Timing diagram showing an example of the generation of the circulation cycle control signal [Figure 10] Functional block diagram showing an example of the configuration of the circulation cycle control signal generation unit [Figure 11] Timing diagram showing the signals generated by the circulation cycle control signal generation unit [Figure 12] Flowchart showing an example of the operation of the circulation cycle control signal generation unit [Figure 13] Functional block diagram showing another example of the configuration of the liquid ejection head [Figure 14] Circuit diagram showing an example of the configuration of the circulation group selection signal generation unit and circuit diagram showing an example of the configuration of the circulation time-division selection signal generation unit [Figure 15] Functional block diagram showing still another example of the configuration of the liquid ejection head [Figure 16] Circuit diagram showing an example of the configuration of the circulation adjustment unit

Mode for Carrying Out the Invention

[0011] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the matters of the present disclosure, and not all combinations of the features described in the present embodiments are essential for the solution means of the present disclosure. The same reference numerals are assigned to the same components. In the following description, first, the basic configuration of the present disclosure will be described, and then, the characteristic parts of the present disclosure will be described.

[0012] <Components of the circulation unit> <Liquid ejection device> First, the schematic configuration of the liquid ejection device 50 in the present embodiment will be described. FIGS. 1(a) and 1(b) are perspective views schematically showing two types of liquid ejection devices.

[0013] The liquid ejection device 50 described in FIGS. 1(a) and 1(b) is a liquid ejection device (serial type liquid ejection device) that performs image recording by ejecting liquid onto a recording medium P by a liquid ejection head that scans in a direction intersecting the conveyance direction of the recording medium P. The present disclosure is not limited to only serial type liquid ejection devices. The present disclosure is also applicable to a page-wide type liquid ejection device that performs image recording by ejecting liquid onto a recording medium conveyed in the conveyance direction using a line head (page-wide head) that is long in the page width direction of the recording medium. In the present embodiment, the liquid ejection head can eject four types of inks: black (K), cyan (C), magenta (M), and yellow (Y), and it is possible to record a full-color image with these inks. The inks that can be ejected from the liquid ejection head are not limited to the above four types of inks. The present disclosure is also applicable to a liquid ejection head for ejecting other types of inks. That is, the type and number of inks ejected from the liquid ejection head are not limited.

[0014] In the serial type liquid ejection device 50, the liquid ejection head 1 is mounted on the carriage 60. The carriage 60 reciprocates along a guide shaft 51 extending in the main scanning direction (X direction). The recording medium is conveyed in the sub-scanning direction (Y direction) that intersects (in this example, is orthogonal to) the main scanning direction by conveyance rollers (conveyance means) 55, 56, 57, 58. In each of the figures referred to below, the Z direction indicates the vertical direction and intersects (in this example, is orthogonal to) the X-Y plane defined by the X direction and the Y direction.

[0015] Figure 1(a) shows a configuration in which a main ink tank 2 is provided outside the liquid ejection head as a liquid storage unit. The liquid (ink) stored in the ink tank 2 is supplied to the sub-ink tank 54 on the liquid ejection head 1 side via an ink supply tube (liquid communication passage) 59, etc., by the driving force of an external pump 21. On the other hand, Figure 1(b) shows a configuration in which there is no main ink tank 2 as a liquid storage unit outside the liquid ejection head, and an ink tank 54B is provided directly above the liquid ejection head 1. In the configuration of Figure 1(b), the liquid ejection head 1 may be provided integrally with the ink tank 54B and configured to be removable / attachable to the carriage 60. Alternatively, the liquid ejection head 1 may be provided integrally with the carriage 60, and only the ink tank 54B may be removable / attachable. The following explanation will use the configuration of Figure 1(a) as a representative example.

[0016] The liquid discharge head 1 is composed of individual discharge units, which will be described later. The specific configuration will be described later, but as shown in Figure 2, the individual discharge unit is provided with a discharge port 211 for discharging liquid and a pressure chamber 212 communicating with the discharge port 211. The individual discharge unit is also provided with a first energy generating element (discharge energy generating element) 214 located in the pressure chamber 212, which generates energy for discharging liquid from the discharge port 211. Furthermore, the individual discharge unit is provided with an individual flow path 223 communicating with the pressure chamber 212 and a second energy generating element (circulation energy generating element) 224 located in the individual flow path 223. The liquid discharge head 1 has a plurality of individual discharge units, and each individual discharge unit has a supply flow path for supplying liquid to its individual flow path.

[0017] When using a liquid ejection head, the ejection of liquid can become unstable due to evaporation of volatile components such as water from the ejection port, and the resulting concentration of solids near the ejection port. Various measures have been taken to prevent this. For example, the liquid ejection device may be equipped with a cap member (not shown) that can cover the ejection port surface of the liquid ejection head, located off-center in the X direction from the transport path of the recording medium. The cap member is used to cover the ejection port surface of the liquid ejection head when recording is not in progress, preventing drying and protecting the ejection port. Furthermore, an ink suction mechanism (not shown) may also be provided, in which case the cap member is used for ink suction from the ejection port. This ink suction refreshes the ink near the ejection port, maintaining the quality of the resulting image. In addition, a method called pre-ejection (pre-discharge) is known, in which concentrated ink is discarded by ejecting ink when recording is not in progress. Furthermore, a method is known in which a small amount of ink is pre-ejected (paper surface pre-ejection / in-page pre-ejection) in an inconspicuous location on the recording medium during recording. While these methods significantly improve image quality, they involve discarding some ink to refresh the ink ejection port. Therefore, it is necessary to minimize the amount of waste ink while refreshing the ejection port.

[0018] To address these challenges, a second energy generating element (circulating energy generating element) 224 is installed in each individual flow path to circulate the ink within the individual flow path. This suppresses the amount of waste ink while also preventing drying at the discharge port and concentration of ink near the discharge port. More specifically, the number of pre-discharge and suction recovery cycles can be minimized. Furthermore, minimizing the number of pre-discharge cycles leads to improvements in throughput and yield.

[0019] The circulating energy generating element 224 does not need to be installed in all individual discharge units of the liquid discharge head. The above-mentioned effects can be obtained by installing it in some individual discharge units compared to not installing it.

[0020] Furthermore, the liquid ejection head shown in Figure 1(a) may be configured such that all parts corresponding to the four types of ink are equipped with a circulating energy generating element 224, or it may be configured such that only the part corresponding to one type of ink is equipped with a circulating energy generating element 224. In other words, the liquid ejection head may not circulate all four types of ink, but may be configured to circulate at least one type of ink.

[0021] <Basic configuration of a liquid dispensing head> Figure 3(a) is an exploded perspective view of the liquid ejection head of this embodiment. As shown in Figure 3, the liquid ejection head 1 includes a sub-ink tank 54 for temporarily storing ink in the head and a liquid ejection tip 301 for ejecting the ink supplied from the sub-ink tank 54 onto the recording medium P. In this embodiment, the liquid ejection head 1 is fixedly supported on the carriage 60 of the liquid ejection device 50 by positioning means (not shown) and electrical contacts provided on the carriage 60. The liquid ejection head 1 ejects ink while moving together with the carriage 60 in the main scanning direction (X direction) shown in Figure 1, and records onto the recording medium P.

[0022] The liquid dispensing head 1 includes a dispensing unit 300, as shown in Figure 3(a). The dispensing unit 300 is composed of a first support member 4, a second support member 7, a liquid dispensing tip 301, and an electrical wiring member (electrical wiring tape) 204.

[0023] An external pump 21, connected to an ink tank 2 which serves as the ink supply source, is equipped with an ink supply tube 59 (see Figure 1(a)). A liquid connector (not shown) is provided at the tip of this ink supply tube 59. When the liquid ejection head 1 is mounted on the liquid ejection device 50, the liquid connector at the tip of the ink supply tube 59 is liquid-tightly connected to the liquid connector insertion port, which is the liquid inlet provided on the head housing 53 of the liquid ejection head 1. This forms an ink supply path from the ink tank 2 through the external pump 21 to the liquid ejection head 1. In this embodiment, since four types of ink are used, four sets of ink tanks 2, external pumps 21, ink supply tubes 59, and sub-ink tanks 54 are provided, corresponding to each ink, and four independent ink supply paths corresponding to each ink are formed. Thus, the liquid ejection device 50 of this embodiment is equipped with an ink supply system that supplies ink from an ink tank 2 located outside the liquid ejection head 1. Note that the liquid ejection device 50 of this embodiment is not equipped with an ink recovery system that recovers the ink in the liquid ejection head 1 into the ink tank. Therefore, the liquid ejection head 1 is provided with a liquid connector inlet for connecting the ink supply tube 59 of the ink tank 2, but it is not provided with a connector inlet for connecting a tube to collect the ink from the liquid ejection head 1 back into the ink tank 2. Note that a separate liquid connector inlet is provided for each ink cartridge.

[0024] Figures 3(b), 3(c), and 3(d) are plan views of the liquid discharge tip 301, which constitutes the liquid discharge head, as seen from the discharge surface side. Figure 3(b) shows a configuration with one tip per four colors, Figure 3(c) shows a configuration with one tip per two colors, and Figure 3(d) shows a configuration with one tip per color. Each liquid discharge tip 301 is provided with a discharge port 211 and a pad 1321 used for electrical mounting. Figure 3(a) shows the single-tip configuration of Figure 3(b).

[0025] Figure 3(b) shows a configuration with one chip per four colors. The four colors are, for example, black, cyan, magenta, and yellow, and each color is assigned to a column extending in the Y direction. In the example shown in the figure, the ejection ports for each color are arranged in a staggered pattern in two columns extending in the Y direction. The pitch of the ejection ports along the Y direction is constant. Alternatively, the ejection ports for each color may be arranged in a single column along the Y direction. Furthermore, the ejection ports for black may be arranged in two columns, while the ejection ports for the other colors are arranged in a single column. In that case, the total number of columns would be five.

[0026] Figure 3(c) shows a configuration where two colors are assigned to one chip, resulting in two chips. In this case, two chips may be mounted on one liquid dispensing head, or one chip may be mounted on one liquid dispensing head, resulting in two heads.

[0027] Figure 3(d) shows a configuration where one color is assigned to each chip, resulting in a total of four chips. In this case, four chips may be mounted on one liquid dispensing head, or one chip may be mounted on each liquid dispensing head, resulting in a total of four heads. Furthermore, two chips may be mounted on each liquid dispensing head, resulting in a total of two heads.

[0028] Furthermore, as shown in Figures 3(c) and 3(d), when the chip is divided into multiple parts, it is not necessary for all chips to have the same length. Also, there are no restrictions on the combination of assigning multiple colors to multiple chips. The same applies when the total number of colors is greater than four (simple straight type).

[0029] Figure 2 is a schematic diagram illustrating in detail the area near the nozzle of a liquid ejection head that ejects liquids such as ink. Figure 2(a) is a plan view as seen from the direction in which the liquid droplets are ejected from the nozzle. Figure 2(b) is a cross-sectional view AA' in Figure 2(a) with the first configuration. Figure 2(c) is a cross-sectional view AA' in Figure 2(a) with the second configuration.

[0030] In Figures 2(a) to 2(c), a partition wall 221 separates the recording element substrate 201 from the orifice plate 202, forming pressure chambers 212 corresponding to each discharge port 211, and individual flow channels 223 for flowing ink through these pressure chambers 212. An ink meniscus forms at each discharge port 211, creating a discharge port interface, which is the interface between the ink and the atmosphere.

[0031] The recording element substrate 201 is equipped with an ejection energy generating element 214 that generates energy to eject ink from the pressure chamber. In this example, an electrothermal conversion element is used as the ejection energy generating element 214. The position of the ejection energy generating element 214 is closer to the second opening (outlet opening) 232 than to the first opening (supply opening) 222, similar to the positions of the ejection port 211 and the pressure chamber 212. By driving the ejection energy generating element 214 to generate heat and foam the ink in the pressure chamber 212, the foaming energy can be used to eject ink from the ejection port 211. The ejection energy generating element 214 is not limited to an electrothermal conversion element as in this example; a piezoelectric element or the like can be used. The recording element substrate 201 is also equipped with a circulating energy generating element 224 that generates energy to create a circulating flow 227 of ink in the individual flow channels, as indicated by the arrows. In this example, an electrothermal conversion element is used as the circulating energy generating element 224. The position of the circulating energy generating element 224 is closer to the first opening 222 than to the second opening 232.

[0032] The individual channel 223 extends in a second direction that intersects (in this example, perpendicular to) the row of discharge ports arranged in a first direction. The individual channel 223 includes a pressure chamber 212, an inlet (upstream) side connecting channel 213A in Figure 2(b) that communicates with one end of the pressure chamber 212, and an outlet (downstream) side channel 213B in Figure 2(b) that communicates with the other end of the pressure chamber 212. The individual channel 223 communicates with a first opening 222 and a second opening 232 that penetrate the recording element substrate 201 on both sides. Therefore, in Figures 2(a), 2(b), and 2(c), the connecting channel 213A is located to the left of the row of discharge ports. The connecting channel 213B is located to the right of the row of discharge ports. Both ends of the individual channel 223 are located on opposite sides of the row of discharge ports.

[0033] The ink flow in the individual channel 223 can be broadly classified into the following two types.

[0034] (1) The ink flow that drives the first energy element 214 and refills after ejection. (2) Ink flow to drive the second energy element 224 and form a circulating flow When the first energy element 214 is driven and liquid is discharged from the discharge port 211, ink flows in from the first opening 222 and the second opening 232 to supply the ink associated with the discharge.

[0035] When the second energy element 224 is driven to form a circulating flow, the ink flows into the individual channel 223 through the first opening 222, which is on the connecting channel side, and flows out to the outside through the second opening 232, which is not on the connecting channel side. In this example, the ink that has flowed out from the second opening 232 is returned to the first opening 222 and circulated, thereby forming a circulating flow 227 indicated by the arrow within the individual channel 223.

[0036] Figure 2(b) shows a configuration in which the first opening 222 and the second opening 232 are connected to individual flow paths 223 and shared outside the liquid discharge head. Figure 2(c) shows a configuration in which the first opening 222 and the second opening 232 are not shared within the tip. Either configuration may be adopted.

[0037] The ink circulation channels inside and outside the liquid ejection head 1 may be equipped with filters to remove foreign matter from the ink. For example, filters may be placed on the inlet side and outlet side, which are outside the individual channel 223. Alternatively, a filter may be placed between the ejection energy generating element 214 and the circulation energy generating element 224 in the individual channel 223. In this case, a filter does not need to be placed on the upstream side (circulation energy generating element 224 side), which is outside the individual channel 223.

[0038] (Drive system of this embodiment: toggle drive) In this embodiment, a selective drive circuit 403, as shown in Figure 4, is formed on the recording element substrate 201. A voltage source (+V) and an external circuit 402 located outside the recording element substrate 201 are connected to the selective drive circuit 403 on the recording element substrate 201. The selective drive circuit 403 includes an on-on drive circuit 404 that turns on and drives either the discharge energy generating element 214 or the circulating energy generating element 224 in response to control signals at each address (for example, N1 to N16) received from the controller 401. Here, the controller 401 controls the drive pulse for driving the discharge energy generating element 214 or the circulating energy generating element 224, and the time interval for applying the drive pulse to each element. Furthermore, if the circulating energy generating element 224 is selected by the on-on drive circuit 404, the on-off drive circuit 405 controls the driving of the circulating energy generating element 224 according to the drive availability signal 406. As described above, in this embodiment, the drive of the circulating energy generating element 224 is controlled by the on-on drive circuit 404 and the on-off drive circuit 405.

[0039] Therefore, if the discharge energy generating element 214 is selected by the on-on drive circuit 404, the discharge energy generating element 4 is driven, and the circulating energy generating element 224 is not driven, regardless of the drive capability signal 406.

[0040] If the second energy generating element 224 is selected by the on-on drive circuit 404, the discharge energy generating element 214 will not be driven, regardless of the drive availability signal 406.

[0041] If the on-on drive circuit 404 selects the second energy generating element 224, and the on-off drive circuit 405 is turned on by the drive feasibility signal 406, the circulating energy generating element 224 is driven.

[0042] If the second energy generating element 224 is selected by the on-on drive circuit 404 and the on-off drive circuit 405 is turned off by the drive availability signal 406, the circulating energy generating element 224 is not driven. Therefore, if the second energy generating element 224 is selected by the on-on drive circuit 404 and the on-off drive circuit 405 is turned off by the drive availability signal 406, neither the discharge energy generating element 214 nor the circulating energy generating element 224 is driven.

[0043] Therefore, the circulating energy generating element 224 is driven according to the drive data of the discharge energy generating element 214 (control signals at each address received from the controller 401) and the drive feasibility signal 406. In this way, the configuration shown in Figure 4 does not require dedicated drive data for the circulating energy generating element 224. Therefore, this configuration has the advantage of reducing the amount of drive data by about half compared to a configuration where dedicated drive data for the circulating energy generating element 224 is required.

[0044] Furthermore, it is possible to control the drive of multiple circulating energy generating elements 224 together based on a common drive / fail signal 406. For example, it is possible to control the drive of circulating energy generating elements B1 to Bn based on a common drive / fail signal 406. In the example shown in Figure 4, n is set to 16. In other words, a total of 32 elements (16 sets of elements) consisting of discharge energy generating elements A1 to A16 and circulating energy generating elements B1 to B16 constitute one group. The circulating energy generating elements B1 to B16 are then controlled on / off by a common drive / fail signal 406. However, n may be changed to other values. If n is 8, the number of elements in the group is 16, and if n is 12, the number of elements in the group is 24.

[0045] Furthermore, while an electrothermal conversion element or a piezoelectric element can be used as the circulating energy generating element 224, an electrothermal conversion element is used in this embodiment. The direction of the circulating flow is as indicated by arrow 227. When a piezoelectric element is used, the direction of the circulating flow may be opposite to the direction of arrow 227 depending on its driving method.

[0046] In this embodiment, a configuration is shown in which a drive enable / disable signal 406 is introduced to the recording element substrate 201 to control the drive of the circulating energy generating element 224. The controller 401, selective drive circuit 403, and on / off drive circuit 405 shown in Figure 4 are formed on the recording element substrate 201. However, this is not limited to this configuration, and some or all of the parts that control the drive of the circulating energy generating element 224 may be provided in the part of the liquid discharge head 1 excluding the recording element substrate 201, or in the part of the liquid discharge device 50 excluding the liquid discharge head 1. For example, at least a part of the controller 401, selective drive circuit 403, and on / off drive circuit 405 may be provided in the part of the liquid discharge head 1 excluding the recording element substrate 201, or in the part of the liquid discharge device 50 excluding the liquid discharge head 1.

[0047] Figure 5 is a block diagram showing the control configuration of the liquid ejection device 50. The host interface 502 receives image data from the host device 501. This image data is stored in the receive buffer 506A provided in the RAM 506. The image processing unit 504 converts the image data into multi-level data of CMYK color components and stores it in the multi-level data buffer 506B provided in the RAM 506. The print data processing unit 505 converts the multi-level data into dot data (binary data) and stores it in the dot data buffer 506C. The liquid ejection head control unit 510 transfers the binary data stored in the dot data buffer 506C to the liquid ejection head 1. The processing in the print data processing unit 505 is synchronized with the heat trigger signal 314 (see Figure 6) output by the timing generation unit 509. The processing in the liquid ejection head control unit 510 is synchronized with the block trigger signal 514 output by the timing generation unit 509. Here, as will be described later, both the heat trigger signal 513 and the block trigger signal 514 are synchronized with encoder signals 511 and 512, which have position information along the scanning direction (main scanning direction) of the liquid ejection head 1. Therefore, the processing in the print data processing unit 505 and the processing in the liquid ejection head control unit 510 are synchronized with the scanning timing of the liquid ejection head 1.

[0048] In Figure 5, 503 indicates an operation panel for the user to give instructions to the liquid dispensing device 50. The processor 507 performs control of the recording element's drive and relative transport control between the recording element and the recording medium (e.g., paper) according to the control program stored in the ROM 508.

[0049] The generation of data transfer timing will be explained using Figure 6. Here, we will explain a method in which the print data for one column is divided into 16 timings (time-division drive). From the encoder that generates an encoder signal having position information along the scanning direction of the liquid ejection head 1, an encoder signal (phase A) 511 and an encoder signal (phase B) which is phase-shifted by one-quarter of a period are input to the timing generation unit 509. The timing generation unit 509 generates a reference pulse 601 at the timing of the rising edge of the encoder signal 511, and generates and outputs a heat trigger signal 513 having intervals equal to the recording resolution by multiplying it. Furthermore, the timing generation unit 509 generates a block trigger signal 514 by dividing the interval of the heat trigger signal 513 into 16. Data is supplied to the liquid ejection head 1 at the timing of this block trigger signal 514. By transferring data within the period of the block trigger signal 514, which is generated based on encoder signals 511 and 512 that have position information of the liquid discharge head 1, images and the like can be recorded at a desired position along the main scanning direction.

[0050] The liquid discharge head control unit 510 will be explained using Figures 7 and 8.

[0051] Figure 7 is a block diagram showing the configuration of the liquid discharge head control unit 510. The liquid discharge head control unit 510 operates based on the timing of the block trigger signal 514 generated by the timing generation unit 509.

[0052] When the clock signal generation unit 701 receives a block trigger signal 514 from the timing generation unit 509, it generates a clock signal of a predetermined number of cycles and transfers that clock signal to the liquid discharge head 1. In the example shown in Figure 8, the clock signal generation unit 701 generates a clock signal for 23 cycles for each period of the latch signal. The number of cycles of the generated clock signal is variable by setting, and the required number of cycles is determined by the number of bits of data to be transferred to the liquid discharge head 1. The clock signal is used, for example, to transmit serial data from the liquid discharge head control unit 510 to the recording element board 201 as a data signal.

[0053] When the block trigger signal 514 is input to the latch signal generation unit 702, it generates a latch signal and transfers it to the recording element board 201 included in the liquid discharge head 1. The latch signal is used, for example, to parallelize and latch serial data transmitted from the liquid discharge head control unit 510 to the recording element board 201.

[0054] The enable signal generation unit 704 generates an enable signal based on the data read from the RAM 506 by the data signal generation unit 703 and transfers it to the liquid discharge head 1. The enable signal is used to specify the duration for which the selected energy generating element is driven during one cycle of the latch signal.

[0055] The cyclic period control signal generation unit 705 (also called the "first generation means" or simply the "generation means") generates a cyclic period control signal. The cyclic period control signal is used to control the period in which the circulating drive element MD2 (see Figures 13 and 15) drives the circulating energy generation element 224. Details will be described later.

[0056] The data signal generation unit 703 generates data signals including a discharge group selection signal (also called a "discharge energy generating element selection signal") and a discharge time-division selection signal. When a block trigger signal 514 is input, the data signal generation unit 703 reads data such as image data from the RAM 506. The data signal generation unit 703 then temporarily stores the discharge group selection signal and discharge time-division selection signal for one time-division drive based on the read data in an internal buffer. The data signal generation unit 703 then transfers the data to the recording element board 201 included in the liquid discharge chip 301 of the liquid discharge head 1 when the next block trigger signal 514 is input. For each block trigger signal 514, data for one time-division drive is transmitted from the liquid discharge head control unit 510 to the recording element board 201 via a data signal.

[0057] Figure 8 shows the data signal, which includes a 40-bit ejection group selection signal (0-39) and a 6-bit ejection time-division selection signal (G0-G5). Of the multiple ejection drive elements MD1 included in the liquid ejection head 1, the ejection drive element MD1 to be activated is determined by the ejection group selection signal and the ejection time-division selection signal transmitted from the liquid ejection head control unit 510. The ejection drive element MD1 thus determined drives the ejection energy generating element 214 corresponding to the period during which the enable signal indicates the enable level, thereby ejecting ink.

[0058] Here, activating a specific discharge drive element MD1 means driving the corresponding discharge energy generating element 214 with the specific discharge drive element MD1. Similarly, activating a specific circulation drive element MD2 means driving the corresponding circulation energy generating element 224 with the specific circulation drive element MD2.

[0059] Figure 8 shows an example where the ejection time-division selection signal is composed of 6 bits (G0 to G5). This allows for a configuration in which a maximum of 64 ejection energy generating elements 214 are included in one block. However, in this embodiment, since only 16 ejection energy generating elements 214 are included in one block, the ejection time-division selection signal only needs to be composed of 4 bits (G0 to G3). Therefore, 2 bits (G4, G5) are left over. To do this, the cyclic period control signal is assigned to G4 or G5 and transferred to the recording element board 201. For example, as shown in Figure 8, the cyclic period control signal is assigned to G4. This makes it possible to control the period for driving the cyclic energy generating element 224, as will be described later. In order to assign the cyclic period control signal to G4, for example, a circuit (not shown) is provided for inserting the cyclic period control signal output by the cyclic period control signal generation unit 705 into the G4 slot of the data signal output by the data signal generation unit 703 shown in Figure 7.

[0060] In the liquid discharge head 1, the circulating drive element MD2 that should drive the circulating energy generating element 224 is determined based on the discharge group selection signal and discharge time division selection signal received from the liquid discharge head control unit 510, as well as the circulating cycle control signal. The circulating drive element MD2 thus determined drives the circulating energy generating element 224 during the period when the enable signal indicates enable.

[0061] Specifically, the circulating drive element MD2 to be activated is narrowed down to the circulating drive element MD2 selected by the discharge time-division selection signal (first narrowing down). Through this first narrowing down, the circulating drive element MD2 to be activated for each group is narrowed down to one.

[0062] Here, the time-division selection signal for discharge is masked by the cyclic period control signal in accordance with this disclosure. That is, even if the time-division selection signal for discharge indicates selection, if the cyclic period control signal indicates non-selection, it is equivalent to the time-division selection signal for discharge indicating non-selection. Therefore, if the cyclic period control signal indicates non-selection, there is no cyclic drive element MD2 that needs to be activated.

[0063] Furthermore, the circulating drive elements MD2 to be activated are narrowed down to those belonging to the group indicated by the discharge group selection signal as unselected (second narrowing down). Note that the combination of groups indicated by the discharge group selection signal as selected and groups indicated as unselected is arbitrary. For example, if the number of groups is 10, the number of combinations is 2^10.

[0064] In this way, the circulating drive element MD2 narrowed down by multiplying the first and second narrowing is selected as the circulating drive element MD2 to be activated. Here, as described above, if the circulating cycle control signal indicates non-selection, there is no circulating drive element MD2 to be activated.

[0065] The time-division selection signal for discharge changes cyclically to select the circulating drive element MD2 to be activated within the group for each latch signal. If the number of circulating drive elements MD2 in the group is N, then one cycle occurs for every N latch signals. Here, for example, if the period of the circulating period control signal is adjusted so that the selection level and non-selection level alternate for every N latches, the period due to the first narrowing can be changed from N to 2N. Alternatively, for example, if the period of the circulating period control signal is adjusted so that the selection level is taken for N latch periods and the non-selection level is taken for 2N latch periods, the period due to the first narrowing can be changed from N to 3N.

[0066] Figure 9 is a timing diagram showing an example of the transfer timing of the discharge group selection signal and the cyclic period control signal. In Figure 9, the cyclic period control signal is shown as a separate signal from the data signal. However, a configuration in which the cyclic period control signal is included as part of the data signal may be adopted, or a configuration in which the cyclic period control signal is transmitted from the liquid discharge head control unit 510 to the recording element board 201 as a separate signal from the data signal may be adopted.

[0067] <When the operating cycle of the discharge drive element and the operating cycle of the circulation drive element are the same> Figure 9(a) shows an example where the cyclic period control signal is not controlled. In 16-time division drive, 16 cyclic energy generating elements 224 belong to one group. One cyclic energy generating element 224 is driven with each latch signal. Therefore, 16 active latch signals constitute one cycle. When the cyclic period control signal is not controlled (i.e., the cyclic period control signal is always at a level that instructs driving), the cyclic period control signal is continuously at the selected level (HIGH level). Therefore, when the cyclic period control signal is not controlled, the operating cycle of the ejection drive element MD1 and the operating cycle of the cyclic drive element MD2 become the same. For example, when the operating cycle of the ejection drive element MD1 in printing is the same as the optimal operating cycle for cyclic operation, the cyclic period control signal should be kept at a level that instructs driving, as shown in Figure 9(a).

[0068] On the other hand, the example shown in Figure 9(b) is an example of controlling the cyclic period control signal. In Figure 9(b), the cyclic period control signal is toggled between a selectable level (HIGH level) and a non-selectable level (LOW level) every 16 latch signals. Therefore, the cyclic period drive element MD2 is operated at twice the operating period of the ejection drive element MD1. For example, the operating frequency of the ejection drive element MD1 in printing may be 20KHz, but the optimal operating frequency for the cyclic period drive element MD2 is 10KHz. In such a case, as shown in Figure 9(b), the cyclic period control signal is toggled every 16 times the latch signal becomes active. By doing this, it is possible to operate the cyclic period drive element MD2 at twice the operating period of the ejection drive element MD1, and at the optimal period for circulation. In order to make the operating period of the cyclic period drive element MD2 N times the operating period of the ejection drive element MD1, the cyclic period control signal should be adjusted as follows. In other words, the cyclical control signal should be configured to alternate between a selection level period having the same length as the period of the discharge time-division selection signal and a non-selection level period having a length that is a multiple of the period of the discharge time-division selection signal (N-1).

[0069] Figure 10 is a functional block diagram showing an example configuration of the cyclic period control signal generation unit 705. The cyclic drive element on-time holding circuit 1001 is a circuit that can set how many times the cyclic period control signal will be continuously turned on by the latch signal, and this number can be set by the processor 507. The cyclic drive element off-time holding circuit 1002 is a circuit that can set how many times the cyclic period control signal will be continuously turned off by the latch signal, and this number can be set by the processor 507.

[0070] The latch count circuit 1003 is a circuit that counts the block trigger signal 514, which is a signal for generating a latch signal. The latch count circuit 1003 counts up in response to the block trigger signal 514 and returns to zero when it has counted the number of block trigger signals set in the cyclic drive element on-time holding circuit 1001. The latch count circuit 1003 continues to count up in response to the block trigger signal 514 and returns to zero when it has counted the number of block trigger signals set in the cyclic drive element off-time holding circuit 1002, and repeats this operation.

[0071] The generation circuit 1004 generates a cycle cycle control signal based on the count value counted by the latch count circuit 1003, the value set in the cycle drive element on time holding circuit 1001, and the value set in the cycle drive element off time holding circuit 1002. In this case, the cycle cycle control signal is not generated when the state set in the data generation enable setting unit 1005 is disabled.

[0072] The operation of the cyclic period control signal generation unit 705 is described using the timing chart in Figure 11. At time t1, the data generation enable setting unit 1005 is set to enable data generation. From time t2, when the data generation enable is set, the latch count circuit 1003 starts counting the block trigger signal 514. The latch count circuit 1003 resets the latch count value to 0 when the count value reaches the value set in the cyclic drive element on time holding circuit 1001 (time t3). The latch count circuit 1003 starts counting up again, and resets the latch count value to zero when it reaches the value set in the cyclic drive element off time holding circuit 1002 (time t4). The above operation is repeated thereafter. During this time, the generation circuit 1004 sets the cyclic period control signal to a HIGH level (i.e., a level corresponding to operation) in section 1 (from time t2 to time t3). Furthermore, the generation circuit 1004 sets the cyclic period control signal to a LOW level (i.e., a level corresponding to inoperability) in section 2 (from time t3 to time t4), and to a HIGH level in section 3.

[0073] The cyclic period control signal generation unit 705 generates a cyclic period control signal, and as described above, the recording element substrate 201 controls the operation of the cyclic drive element MD2 based on the ejection group selection signal, the ejection time division selection signal, and the cyclic period control signal. This makes it possible to operate the cyclic drive element MD2 at a different cycle than the ejection drive element MD1.

[0074] The control flow for generating the cyclical control signal is explained using Figure 12. In step S1201, the operating cycle of the ejection drive element MD1 in printing is determined.

[0075] In step S1202, the operating period of the fastest circulating drive element MD2 is compared with the operating period of the discharge drive element MD1 determined in step S1201. If the operating period of the discharge drive element MD1 is longer than the fastest circulating operating period, step S1203 is performed. If the operating period of the discharge drive element MD1 is shorter than the fastest circulating operating period, step S1204 is performed.

[0076] In step S1203, the off-time of the circulating drive element is set to zero in the circulating drive element off-time holding circuit 1002.

[0077] In step S1204, the on-time holding circuit 1001 and the off-time holding circuit 1002 for the circulating drive element are set to have a circulating period for the on-time and off-time of the circulating drive element.

[0078] In step S1205, it is determined whether the data generation enable setting unit 1005 is enabled or disabled. Note that the setting in the data generation enable setting unit 1005 can be made at any time.

[0079] If the disable function is set in step S1205, the cycle control signal in the generation circuit 1004 is set to zero in step 1206.

[0080] If enable is set in step S1205, the value set in the circulating drive element off-time holding circuit 1002 is checked in step S1207.

[0081] If the set value for the off-time of the circulating drive element in step S1207 is zero, the circulating cycle control signal in the generation circuit 1004 is set to 1 in step S1208. If the set value for the off-time of the circulating drive element in step S1207 is not zero, step S1209 is performed.

[0082] In steps S1209, S1210, S1211, and S1212, the drive capability data for the circulating drive element is set to 1, and then the system waits until the circulating drive ON time has elapsed. Then the drive capability data for the circulating drive element is set to zero, and then the system waits until the circulating drive OFF time has elapsed. The system then returns to S1205. By repeating steps S1209 through S1212 via S1205 and S1207, a circulating cycle control signal is repeatedly generated in which 1 persists for the duration of the circulating drive ON time and zero persists for the duration of the circulating drive OFF time.

[0083] The circulating operation controlled as described above can be performed in any state of the inkjet recording device, including while printing is being performed while scanning the liquid ejection head, or when the liquid ejection head is stopped.

[0084] Figure 13 shows the circuit configuration of the recording element substrate 201 in the embodiment, as well as the liquid discharge head control unit 510 and power supply circuit 1301 mounted on the main body 50M of the liquid discharge device 50. The recording element substrate 201 includes a plurality of discharge modules 1311 and a plurality of circulation modules 1312.

[0085] Each ejection module 1311 includes an ejection heater (electric heat conversion element) RhA that functions as an ejection energy generating element 214. The ejection module 1311 also includes an ejection drive element (transistor) MD1 for supplying current to the heater RhA, and an ejection logic circuit AND1 for selectively operating the ejection drive element MD1. By supplying current to the ejection heater RhA, heat is generated, causing the ink to foam and eject, enabling recording onto the recording paper.

[0086] Each circulation module 1312 includes a circulation heater (electric heat conversion element) RhB that functions as a circulation energy generating element 224. Each circulation module 1312 also includes a circulation drive element (transistor) MD2 for supplying current to the heater RhB, and a circulation logic circuit AND2 for selectively operating the circulation drive element MD2. By supplying current to the circulation heater RhB, heat is generated, causing ink bubbles to grow and creating a circulation flow in the ink supply channel.

[0087] Furthermore, a piezoelectric element can be used instead of the ejection heater RhA as the ejection energy generating element 214 for ejecting ink. Similarly, a piezoelectric element can be used instead of the circulation heater RhB as the circulation energy element 224 for circulating ink.

[0088] The discharge logic circuit AND1 is supplied with a discharge group selection signal 1319, a discharge time-division selection signal 1318, and an enable signal HE. The discharge group selection signal 1319 and the discharge time-division selection signal 1318 are output from the control data supply circuit 1331. The enable signal HE is used to control the pulse width (the time during which the discharge drive element MD1 is turned on and current is flowing), and as described above, it is supplied from the enable signal generation unit 704 of the liquid discharge head control unit 510.

[0089] When the discharge group selection signal 1319 indicates selection, the discharge time division selection signal 1318 indicates selection, and the enable signal HE indicates enable, the output of the discharge logic circuit AND1 becomes HIGH level. As a result, the discharge drive element MD1 becomes conductive and current flows to the discharge heater RhA.

[0090] The discharge logic circuit AND2 is supplied with a circulating group selection signal (also called the "circulating energy generation element selection signal") 1320, a circulating time-division selection signal 1333, and an enable signal HE. The circulating group selection signal 1320 and the circulating time-division selection signal 1333 are output from the control data supply circuit 1331. The enable signal HE is used to control the pulse width (the time during which the circulating drive element MD2 is turned on and current is flowing), and as described above, it is supplied from the enable signal generation unit 704 of the liquid discharge head control unit 510.

[0091] When the cyclic group selection signal 1320 indicates selection, the cyclic time-division selection signal 1333 indicates selection, and the enable signal HE indicates enable, the output of the cyclic logic circuit AND2 becomes HIGH level. As a result, the cyclic drive element MD2 becomes conductive and current flows to the cyclic heater RhB.

[0092] The control data supply circuit 1331 is configured to include, for example, shift registers 1313a, 1313b, and 1313c and latch circuits 1314a, 1314b, and 1314c, as shown in the figure. The control data supply circuit 1331 has external input terminals for a clock signal CLK, a data signal DATA, and a latch signal LT. The clock signal CLK is for serial data transfer of selection information for the dispensing module 1311 and the circulation module 1312 to the shift registers 1313a, 1313b, and 1313c. The latch signal LT is for the latch circuits 1314a, 1314b, and 1314c to hold the selection information. The clock signal CLK, data signal DATA, and latch signal LT are supplied from the clock signal generation unit 701, data signal generation unit 703, and latch signal generation unit 702 of the liquid dispensing head control unit 510, respectively.

[0093] The enable signal HE is a signal used to adjust the current pulse width so that more desired thermal energy can be generated, taking into account manufacturing variations in heater resistance values ​​on the recording element substrate 201, manufacturing variations in power supplies, etc., and voltage drops in power supply wiring when multiple heaters are driven simultaneously. It is preferable to have separate enable signals HE for the ejection heater and the circulation heater, and to control the pulse width of each separately. In this embodiment, one enable signal HE is shared between the ejection heater and the circulation heater to reduce the number of signal terminals, so it is not possible to control the pulse width of the ejection heater and the circulation heater separately. Therefore, it is preferable to form the ejection heater RhA and the circulation heater RhB in the same process of the semiconductor manufacturing process, and to adjust the pulse width with one enable signal HE, assuming that the two types of heaters are made with the same manufacturing variation (amount of resistance value deviation from the ideal value).

[0094] Here, we will explain the drive control method for a series of ejector heaters 1321 having m groups, where each group consists of n ejector heaters RhA. For example, assuming a recording element substrate with heater rows arranged at a density of 600 dpi within a 1-inch length, the control method for the ejector heaters RhA in a series of (n=16) × (m=40 groups) is described below.

[0095] Each ejection module 1311 contains one ejection heater RhA. A group contains 16 modules. The n=16 ejection modules 1311 within each group are time-division driven by the ejection time-division selection signal 1318. Time-division driving is a method of controlling the system to divide the time of a certain ejection cycle into n=16 units and to sequentially select one ejection module 1311 at a time for each divided unit time. Within each group, multiple ejection heaters RhA are never selected simultaneously, and all time-division defined ejection modules 1311 are controlled to be selected exactly once within one ejection cycle. At this time, only one signal line of the ejection time-division selection signal 1318 is selected, so by incorporating the ejection decoder circuit 1315 as shown in Figure 13, the amount of serial data transferred from the inkjet recording device 50 can be further reduced. The ejection decoder circuit 1315 expands the number of output data bits to 2 to the power of q, where q is the number of bits of the input data encoded in binary. Specifically, when 4-bit data is input to the ejection decoder circuit 1315, it is converted to 2 to the power of 4 = 16 bits of output data. In this case, the output signal is output as information in which only 1 bit of the 16 bits is valid. Unless there is a special application, it is preferable to use all the signal lines output from the ejection decoder circuit 1315 as the ejection time-division selection signal 1318, as this is the most efficient use of input data. Note that as the amount of data transferred in serial transfer increases, faster serial data transfer speeds are required. In the inkjet recording device 50 and recording element board 201, this leads to increased costs and size of signal transmission and reception circuits and transmission lines, so it is preferable to reduce the amount of data as much as possible.

[0096] An m-bit discharge group selection signal 1319 for selecting and driving each of the m groups is output from the control data supply circuit 1331. The group selection is a control that allows simultaneous selection, and m bits of information, equal to the number of groups, are serially transferred from the data signal generation unit 703 included in the liquid discharge head control unit 510. As described above, the discharge module 1311 is selected and controlled so that current flows to the discharge heater RhA at the corresponding location when the discharge group selection signal 1319, the discharge time division selection signal 1318, and the enable signal HE are input to the discharge logic circuit AND1. In this embodiment, n=16 and m=40 are used as an example, but similar control can be performed with other values ​​such as n=8 and m=80, or with different nozzle lengths such as n=32 and m=40. However, since the time division number n is configured to use the output signal of the decoder circuit as the selection signal, it is preferable to use a value expressed as a power of 2 (n=2, 4, 8, 16, 32...).

[0097] Next, the drive control method for the circulating heater array 1322 will be described. The circulating heater RhB functions as a circulating energy generating element 224 that generates an ink circulating flow 227 in an individual channel 223 adjacent to the ejection port 211 (see Figure 2). The circulating heater RhB is paired with the ejection heater RhA, which is located directly below the ejection port 211, and is also positioned in close proximity to the ejection heater RhA. In this embodiment, a method will be described for selecting and controlling a circulating heater array 1322, which consists of the same number of circulating heaters RhB as the number of ejection heaters RhA (n=16) × (m=40 groups), from the main body 50M of the inkjet recording device 50.

[0098] One circulation module 1311 contains one circulation heater RhB. One group contains 16 modules.

[0099] The frequency at which the latch signal LT becomes active is defined as the unit frequency, and the period corresponding to this unit frequency is defined as the unit period. (Here, the unit period is the same as the unit period for selection / deselection of each ejection time division selection signal 1318. In other words, each ejection time division selection signal 1318 can be selected or deselected for each unit period.) The n ejection drive elements MD1 included in each group are driven sequentially in a cycle period of n × unit period. In contrast, the n cyclic drive elements MD2 included in each group are driven sequentially in a cycle period of p × unit period. In the configuration shown in Figure 13, for example, p = n, 2 × n, 3 × n, 4 × n, ... That is, with a as an integer, p = a × n. If n is 16, then p is 16, 32, 48, 64, ... The cyclic period control signal is active during a period of n, and inactive during a period of (a-1) × n. For this purpose, the cyclic period control signal generation unit 705 generates a cyclic period control signal that has one active period and no inactive period, or has one or more inactive periods, with the cycle of the discharge time division selection signal 1318 as the unit.

[0100] Here, p is an integer multiple of n in the above explanation, but it does not necessarily have to be an integer multiple of n. As will be described later, in the configuration shown in Figure 15, p can be set so that p = n+1, n+2, n+3, ... That is, p = n+b, where b is a non-negative integer. In this case, the cyclic period control signal is active during the period of n, and inactive during the period of b. At this time, the drive period of the circulating energy generation element 224 can be set to (p / n) times the drive period of the discharge energy generation element 214.

[0101] In the configuration shown in Figure 13, we will now explain the part related to the circulating drive element MD2.

[0102] The control data supply circuit 1331 shown in Figure 13 includes a cyclic group selection signal generation unit 1316 and a cyclic time-division selection signal generation unit 1341. The cyclic time-division selection signal generation unit 1341 constitutes a second generation means on the recording element substrate 201 shown in Figure 13.

[0103] The circulation group selection signal generation unit 1316 is for generating each circulation group selection signal 1320 based on each discharge group selection signal 1319.

[0104] The circulation time-division selection signal generation unit 1341 is for generating each circulation time-division selection signal 1333 based on each discharge time-division selection signal 1318 and circulation cycle control signal 1342.

[0105] Figure 14(a) shows a circuit diagram illustrating the configuration of the cyclic group selection signal generation unit 1316. As shown in the figure, the cyclic group selection signal generation unit 1316 includes a logic inversion gate for logically inverting each discharge group selection signal 1319 and a logic AND gate that takes the logic AND of the logically inverted discharge group selection signal 1319 and the cyclic flag signal 1317. The output of each logic AND gate is used as the respective cyclic group selection signal 1320.

[0106] The number of these gates is equal to the number of groups; for example, if there are 40 groups, then the number of these gates is 40.

[0107] By setting the circulation flag signal 1317 to indicate invalidity, the selection of the circulation module 1312 can be prohibited during normal recording operations that do not require ink circulation.

[0108] When the circulation flag signal 1317 indicates that it is valid, each circulation group selection signal 1320 becomes the logical inversion of each discharge group selection signal 1319.

[0109] Figure 14(b) shows a circuit diagram illustrating the configuration of the cyclic time-division selection signal generation unit 1341. As shown in the figure, the cyclic time-division selection signal generation unit 1341 includes a logic gate that takes the logical AND of each discharge time-division selection signal 1318 and the cyclic period control signal 1342. The output of each logical AND gate is used as the respective cyclic time-division selection signal 1333.

[0110] For example, as shown in Figure 11, the cyclic period control signal 1342 has a logic level of HIGH during the period when the latch count is from 0 to 15, and a logic level of LOW during the subsequent period when the latch count is from 0 to 31. In this case, during the first 16 unit periods, the 16 cyclic time division selection signals 1333 are sequentially at the HIGH level. Then, during the following 32 unit periods, all 16 cyclic time division selection signals 1333 are at the LOW level. Therefore, the period of each cyclic time division selection signal 1333 is 48. This is three times the period of each discharge time division selection signal 1318. In this way, the period of each cyclic time division selection signal 1333 can be made three times the period of each discharge time division selection signal 1318.

[0111] For example, during periods when recording is not being performed, the logic level of all discharge group selection signals 1319 is set to LOW, and the logic level of the cycle flag signal 1317 is kept HIGH. By doing this, all cycle heaters RhB belonging to each group can be driven cyclically during this period. In this case, the cycle period can be controlled by adjusting the period of the cycle cycle control signal 1342.

[0112] In the configuration shown in Figure 13, if the periods during which the logic level of the cyclic period control signal 1342 is HIGH and LOW are integer multiples of the period of the discharge time division selection signal 1318, then there will be no fluctuation in the period during which each cyclic heater RhB is driven. In the operation example in Figure 11, the j-th cyclic heater RhB in each group is driven in the (i × 48 + j)th period when viewed in terms of unit periods. However, if the periods during which the logic level of the cyclic period control signal 1342 is HIGH and LOW are not integer multiples of the period of the discharge time division selection signal 1318, then there will be fluctuations in the period during which each cyclic heater RhB is driven. For example, if the period of the discharge time division selection signal 1318 is 24, and the period during which the logic level is HIGH is 16 and the period during which the logic level is LOW is 8 in each period, then the following will occur. For example, the zeroth cyclic heater RhB will be driven in the 0th period, the 32nd period, the 48th period, ... In this case, the driving intervals would be 32 cycles, 16 cycles, 32 cycles, 16 cycles, ... Similarly, the driving intervals for the circulating heaters RhB from the 1st to the 15th would be 32 cycles, 16 cycles, 32 cycles, 16 cycles, ...

[0113] In contrast, the configuration shown in Figure 15 allows for equal intervals between the operation of each circulating heater RhB in such cases. In other words, in the example above, the interval between the operation of each circulating heater RhB can always be set to 24 cycles. To achieve this, in each cycle, the logic level of the circulating cycle control signal 1342 is set to HIGH for 12 periods and to LOW for 12 periods.

[0114] In the configuration shown in Figure 15, we will now explain the part related to the circulating drive element MD2.

[0115] The control data supply circuit 1331 shown in Figure 15 includes a cyclic group selection signal generation unit 1316, a cyclic counter 1501, a cyclic decoder 1502, and a cyclic adjustment unit 1503. The cyclic counter 1501, the cyclic decoder 1502, and the cyclic adjustment unit 1503 constitute a second generation means on the recording element substrate 201 shown in Figure 15.

[0116] The circulation group selection signal generation unit 1316 is the same as that shown in Figure 13, and is for generating each circulation group selection signal 1320 based on each discharge group selection signal 1319.

[0117] The cyclic counter 1501 is a counter that receives the cyclic period control signal 1342 as an enable signal and the latch signal LT as a clock signal. The cyclic counter 1501 counts up at the same frequency d as the unit frequency of selection / deselection of the output time division selection signal when the cyclic period control signal 1342 is active, and pauses counting up when the cyclic period control signal 1342 is inactive. In this example, the cyclic counter 1501 cyclically counts up from 0 to 15 by the latch signal LT when the logic level of the cyclic period control signal 1342 is HIGH.

[0118] The cyclic decoder 1502 decodes the 4-bit output of the cyclic counter 1501, which represents a number between 0 and 15, and expands it into a 16-bit signal 1504. Therefore, the level of the 16-bit output signal 1504 of the cyclic decoder 1502 becomes HIGH cyclically. Also, because the logic level of the cyclic period control signal 1342 is LOW, the output signal 1504, whose logic level is HIGH, does not change when the cyclic counter 1501 is stopped.

[0119] As shown in Figure 16, the cycle adjustment unit 1503 takes a logical AND operation with the LT signal for each of the 16 output signals 1504 of the cycle decoder 1502, and outputs the result as each cycle time division selection signal 1333. Therefore, when the logic level of the cycle period control signal 1342 is LOW, the logic levels of all cycle time division selection signals 1333 become LOW.

[0120] For example, as shown in Figure 11, the cyclic period control signal 1342 has a logic level of HIGH during the period when the latch count is from 0 to 15, and a logic level of LOW during the subsequent period when the latch count is from 0 to 31. In this case, during the first 16 unit periods, the 16 cyclic time division selection signals 1333 are sequentially at the HIGH level. Then, during the following 32 unit periods, all 16 cyclic time division selection signals 1333 are at the LOW level. Therefore, the period of each cyclic time division selection signal 1333 is 48. This is three times the period of each discharge time division selection signal 1318. In this way, the period of each cyclic time division selection signal 1333 can be made three times the period of each discharge time division selection signal 1318.

[0121] For example, during periods when recording is not being performed, the logic level of all discharge group selection signals 1319 is set to LOW, and the logic level of the cycle flag signal 1317 is kept HIGH. By doing this, all cycle heaters RhB belonging to each group can be driven cyclically during this period. In this case, the cycle period can be controlled by adjusting the period of the cycle cycle control signal 1342.

[0122] In the configuration shown in Figure 15, as described above, even if the period of the circulation period control signal 1342 is not an integer multiple of the period of the discharge time division selection signal 1318, the intervals at which each circulation heater RhB is driven can be made equal. In other words, in the example above, the interval at which each circulation heater RhB is driven can always be set to 24 periods.

[0123] <Other Embodiments> In the above embodiment, an inkjet recording device that ejects ink from a liquid ejection head was used as an example; however, the inkjet recording device can also be used as a liquid ejection device that ejects liquids other than ink from a liquid ejection head.

[0124] <Technical Features of This Disclosure> This disclosure includes the following components:

[0125] [Configuration 1] A liquid dispensing head for dispensing liquid onto a recording medium, A liquid discharge head control unit for controlling the liquid discharge head, A liquid dispensing device comprising, The aforementioned liquid dispensing head is Multiple outlets for dispensing liquid, Multiple pressure chambers communicating with the aforementioned multiple discharge ports, Multiple discharge energy generating elements that generate energy to discharge the liquid in the multiple pressure chambers from the multiple discharge ports, Multiple circulating energy generating elements that generate energy to circulate the liquid in the multiple pressure chambers inside the liquid discharge head, A means for inputting multiple discharge energy generation element selection signals, multiple discharge time-division selection signals, and a cyclic period control signal, Equipped with, The liquid is circulated by driving the circulating energy generating element selected by the circulating energy generating element selection signal and the circulation time-division selection signal. The liquid discharge head control unit is The system includes a first generation means for generating the cyclic period control signal such that the periods of the multiple cyclic time-division selection signals are the same as or longer than the periods of the multiple discharge time-division selection signals. Liquid discharge device.

[0126] [Configuration 2] The liquid discharge head further comprises a second generation means for generating each of the time-division selection signals for circulation based on each of the time-division selection signals for discharge and the circulation cycle control signal. A liquid dispensing device as described in Configuration 1.

[0127] [Configuration 3] The first generation means generates a cyclic period control signal that is continuously at a selection level, or a cyclic period control signal that repeats a period of selection level having the same length as the period of the discharge time-division selection signal and a period of non-selection level having a length that is a multiple of the period of the discharge time-division selection signal. The second generation means generates a circulating time-division selection signal identical to the discharge time-division selection signal when the circulating cycle control signal is at a selection level, and generates a circulating time-division selection signal that is at a non-selection level when the circulating cycle control signal is at a non-selection level. The liquid dispensing device described in Configuration 2.

[0128] [Structure 4] The liquid discharge head further comprises a second generation means for generating each of the time-division selection signals for circulation based on the circulation cycle control signal. A liquid dispensing device as described in Configuration 1.

[0129] [Composition 5] The first generation means generates a cyclic cycle control signal that is continuously at a selection level, or a cyclic cycle control signal that repeats a selection level period that is an integer multiple of the period during which each of the discharge time-division selection signals is at a selection level, and a non-selection level period that is an integer multiple of the period during which each of the discharge time-division selection signals is at a selection level. The second generating means is A circulating counter that counts up each time the time-division selection signal for discharge, which has a selection level, switches during the period when the circulating cycle control signal is at a selection level, and pauses counting up during the period when the circulating cycle control signal is at a non-selection level, A means for generating a plurality of cycle time division selection signals by taking a logical AND of a plurality of signals obtained by expanding the count value output by the cycle counter and the cycle period control signal, Equipped with, The liquid dispensing device described in configuration 4.

[0130] [Composition 6] The liquid discharge head further comprises means for generating each of the circulating energy generating element selection signals based on each of the discharge energy generating element selection signals. A liquid dispensing device according to any one of configurations 1 to 5.

[0131] [Composition 7] The liquid discharge head discharges the liquid by driving the discharge energy generating element selected by the discharge energy generating element selection signal and the discharge time-division selection signal. A liquid dispensing device according to any one of configurations 1 to 6.

[0132] [Structure 8] The discharge energy generating element selected by the discharge energy generating element selection signal and the discharge time-division selection signal discharges the liquid according to an enable signal that specifies the period for which the discharge energy generating element is driven. The liquid dispensing device described in configuration 7.

[0133] [Composition 9] The circulating energy generating element selected by the circulating energy generating element selection signal and the circulating time-division selection signal circulates the liquid according to an enable signal that specifies the period for which the circulating energy generating element is driven. A liquid dispensing device according to any one of configurations 1 to 8.

[0134] [Configuration 10] Each of the plurality of discharge energy generation element selection signals corresponds to each of the plurality of circulating energy generation element selection signals, Each of the aforementioned circulating energy generation element selection signals becomes a non-selection level if the corresponding discharge energy generation element selection signal is at a selection level. A liquid dispensing device according to any one of configurations 1 to 9.

[0135] [Composition 11] Each of the aforementioned circulating energy generation element selection signals will be selected or deselected according to the circulation flag if the corresponding discharge energy generation element selection signal is at a non-selection level. A liquid dispensing device as described in configuration 10.

[0136] [Composition 12] A liquid discharge head control device for controlling a liquid discharge head for dispensing liquid onto a recording medium, The aforementioned liquid dispensing head is Multiple outlets for dispensing liquid, Multiple pressure chambers communicating with the aforementioned multiple discharge ports, Multiple discharge energy generating elements that generate energy to discharge the liquid in the multiple pressure chambers from the multiple discharge ports, Multiple circulating energy generating elements that generate energy to circulate the liquid in the multiple pressure chambers inside the liquid discharge head, A means for inputting multiple discharge energy generation element selection signals, multiple discharge time-division selection signals, and a cyclic period control signal, Equipped with, The liquid is circulated by driving the circulating energy generating element selected by the circulating energy generating element selection signal and the circulation time-division selection signal. The liquid discharge head control device is The system includes a generation means for generating the cyclic period control signal such that the periods of the multiple cyclic time-division selection signals are the same as or longer than the periods of the multiple discharge time-division selection signals. Liquid dispensing head control device.

[0137] [Composition 13] A liquid dispensing head for dispensing liquid onto a recording medium, The liquid dispensing head is controlled by a liquid dispensing head control device. The aforementioned liquid dispensing head is Multiple outlets for dispensing liquid, Multiple pressure chambers communicating with the aforementioned multiple discharge ports, Multiple discharge energy generating elements that generate energy to discharge the liquid in the multiple pressure chambers from the multiple discharge ports, Multiple circulating energy generating elements that generate energy to circulate the liquid in the multiple pressure chambers inside the liquid discharge head, A means for inputting multiple discharge energy generation element selection signals, multiple discharge time-division selection signals, and a cyclic period control signal, Equipped with, The liquid is circulated by driving the circulating energy generating element selected by the circulating energy generating element selection signal and the circulation time-division selection signal. The liquid discharge head control device is The system includes a generation means for generating the cyclic period control signal such that the periods of the multiple cyclic time-division selection signals are the same as or longer than the periods of the multiple discharge time-division selection signals. Liquid dispensing head.

[0138] [method] A liquid dispensing head control method for controlling a liquid dispensing head for dispensing liquid onto a recording medium, The aforementioned liquid dispensing head is Multiple outlets for dispensing liquid, Multiple pressure chambers communicating with the aforementioned multiple discharge ports, Multiple discharge energy generating elements that generate energy to discharge the liquid in the multiple pressure chambers from the multiple discharge ports, Multiple circulating energy generating elements that generate energy to circulate the liquid in the multiple pressure chambers inside the liquid discharge head, A means for inputting multiple discharge energy generation element selection signals, multiple discharge time-division selection signals, and a cyclic period control signal, Equipped with, The liquid is circulated by driving the circulating energy generating element selected by the circulating energy generating element selection signal and the circulation time-division selection signal. The liquid discharge head control method is as follows: The step of generating the cyclic period control signal such that the periods of the multiple cyclic time-division selection signals are the same as or longer than the periods of the multiple discharge time-division selection signals, Liquid dispensing head control method.

Claims

1. A liquid dispensing head for dispensing liquid onto a recording medium, A liquid discharge head control unit for controlling the liquid discharge head, A liquid dispensing device comprising, The aforementioned liquid dispensing head is Multiple outlets for dispensing liquid, Multiple pressure chambers communicating with the aforementioned multiple discharge ports, Multiple discharge energy generating elements that generate energy to discharge the liquid in the multiple pressure chambers from the multiple discharge ports, Multiple circulating energy generating elements that generate energy to circulate the liquid in the multiple pressure chambers inside the liquid discharge head, A means for inputting multiple discharge energy generation element selection signals, multiple discharge time-division selection signals, and a cyclic period control signal, Equipped with, The liquid is circulated by driving the circulating energy generating element selected by the circulating energy generating element selection signal and the circulation time-division selection signal. The liquid discharge head control unit is The system includes a first generation means for generating the cyclic period control signal such that the periods of the multiple cyclic time-division selection signals are the same as or longer than the periods of the multiple discharge time-division selection signals. Liquid discharge device.

2. The liquid discharge head further comprises a second generation means for generating each of the time-division selection signals for circulation based on each of the time-division selection signals for discharge and the circulation cycle control signal. The liquid dispensing device according to claim 1.

3. The first generation means generates a cyclic period control signal that is continuously at a selection level, or a cyclic period control signal that repeats a period of selection level having the same length as the period of the discharge time-division selection signal and a period of non-selection level having a length that is a multiple of the period of the discharge time-division selection signal. The second generation means generates a circulating time-division selection signal identical to the discharge time-division selection signal when the circulating cycle control signal is at a selection level, and generates a circulating time-division selection signal that is at a non-selection level when the circulating cycle control signal is at a non-selection level. The liquid dispensing device according to claim 2.

4. The liquid discharge head further comprises a second generation means for generating each of the time-division selection signals for circulation based on the circulation cycle control signal. The liquid dispensing device according to claim 1.

5. The first generation means generates a cyclic period control signal that is continuously at a selection level, or a cyclic period control signal that repeats a selection level period that is an integer multiple of the period during which each of the discharge time-division selection signals is at a selection level, and a non-selection level period that is an integer multiple of the period during which each of the discharge time-division selection signals is at a selection level. The second generating means is, A circulating counter that counts up each time the time-division selection signal for discharge, which has a selection level, switches during the period when the circulating cycle control signal is at a selection level, and pauses counting up during the period when the circulating cycle control signal is at a non-selection level, A means for generating a plurality of cycle time division selection signals by taking a logical AND of a plurality of signals obtained by expanding the count value output by the cycle counter and the cycle period control signal, Equipped with, The liquid dispensing device according to claim 4.

6. The liquid discharge head further comprises means for generating each of the circulating energy generating element selection signals based on each of the discharge energy generating element selection signals. The liquid dispensing device according to claim 1.

7. The liquid discharge head discharges the liquid by driving the discharge energy generating element selected by the discharge energy generating element selection signal and the discharge time-division selection signal. The liquid dispensing device according to claim 1.

8. The discharge energy generating element selected by the discharge energy generating element selection signal and the discharge time-division selection signal discharges the liquid according to an enable signal that specifies the period for which the discharge energy generating element is driven. The liquid dispensing device according to claim 7.

9. The circulating energy generating element selected by the circulating energy generating element selection signal and the circulating time-division selection signal circulates the liquid according to an enable signal that specifies the period for which the circulating energy generating element is driven. The liquid dispensing device according to claim 1.

10. Each of the plurality of discharge energy generation element selection signals corresponds to each of the plurality of circulating energy generation element selection signals, Each of the aforementioned circulating energy generation element selection signals becomes a non-selection level if the corresponding discharge energy generation element selection signal is at a selection level. The liquid dispensing device according to claim 1.

11. Each of the aforementioned circulating energy generation element selection signals will be selected or deselected according to the circulation flag if the corresponding discharge energy generation element selection signal is at a non-selection level. The liquid dispensing device according to claim 10.

12. A liquid discharge head control device for controlling a liquid discharge head for dispensing liquid onto a recording medium, The aforementioned liquid dispensing head is Multiple outlets for dispensing liquid, Multiple pressure chambers communicating with the aforementioned multiple discharge ports, Multiple discharge energy generating elements that generate energy to discharge the liquid in the multiple pressure chambers from the multiple discharge ports, Multiple circulating energy generating elements that generate energy to circulate the liquid in the multiple pressure chambers inside the liquid discharge head, A means for inputting multiple discharge energy generation element selection signals, multiple discharge time-division selection signals, and a cyclic period control signal, Equipped with, The liquid is circulated by driving the circulating energy generating element selected by the circulating energy generating element selection signal and the circulation time-division selection signal. The liquid discharge head control device is The system includes a generation means for generating the cyclic period control signal such that the periods of the multiple cyclic time-division selection signals are the same as or longer than the periods of the multiple discharge time-division selection signals. Liquid dispensing head control device.

13. A liquid dispensing head for dispensing liquid onto a recording medium, The liquid dispensing head is controlled by a liquid dispensing head control device. The aforementioned liquid dispensing head is Multiple outlets for dispensing liquid, Multiple pressure chambers communicating with the aforementioned multiple discharge ports, Multiple discharge energy generating elements that generate energy to discharge the liquid in the multiple pressure chambers from the multiple discharge ports, Multiple circulating energy generating elements that generate energy to circulate the liquid in the multiple pressure chambers inside the liquid discharge head, A means for inputting multiple discharge energy generation element selection signals, multiple discharge time-division selection signals, and a cyclic period control signal, Equipped with, The liquid is circulated by driving the circulating energy generating element selected by the circulating energy generating element selection signal and the circulation time-division selection signal. The liquid discharge head control device is The system includes a generation means for generating the cyclic period control signal such that the periods of the multiple cyclic time-division selection signals are the same as or longer than the periods of the multiple discharge time-division selection signals. Liquid dispensing head.

14. A liquid dispensing head control method for controlling a liquid dispensing head for dispensing liquid onto a recording medium, The aforementioned liquid dispensing head is Multiple outlets for dispensing liquid, Multiple pressure chambers communicating with the aforementioned multiple discharge ports, Multiple discharge energy generating elements that generate energy to discharge the liquid in the multiple pressure chambers from the multiple discharge ports, Multiple circulating energy generating elements that generate energy to circulate the liquid in the multiple pressure chambers inside the liquid discharge head, A means for inputting multiple discharge energy generation element selection signals, multiple discharge time-division selection signals, and a cyclic period control signal, Equipped with, The liquid is circulated by driving the circulating energy generating element selected by the circulating energy generating element selection signal and the circulation time-division selection signal. The liquid discharge head control method is as follows: The step of generating the cyclic period control signal such that the periods of the multiple cyclic time-division selection signals are the same as or longer than the periods of the multiple discharge time-division selection signals, Liquid dispensing head control method.

Images