JP6696294B2 - Drive waveform generation device, device for ejecting liquid - Google Patents

Description

  The present invention relates to a drive waveform generation device, a head drive device, and a device that ejects liquid.

  When the liquid is ejected from the liquid ejecting head, if the distance between the head and the landing surface on which the liquid adheres is long, the mist generated due to the ejection of the liquid easily floats.

  Conventionally, when the distance from the head to the landing surface is long, there is one that attempts to suppress the generation of mist by slowing down the ejection speed of droplets (Patent Document 1).

JP, 2006-248001, A

  As described above, when the mist generated by the liquid ejection becomes easy to float, the floating mist adheres to the inside of the device and stains the inside of the device, and adheres to the nozzle surface of the head to cause nozzle clogging and ejection bending. There is a problem called.

  The present invention has been made in view of the above problems, and an object thereof is to reduce the occurrence of mist.

In order to solve the above problems, the drive waveform generation device according to claim 1 of the present invention is
A device for generating a drive waveform including a plurality of drive pulses in time series for ejecting liquid from a liquid ejection head,
The drive waveform is a waveform in which the speed of the liquid ejected in the final drive pulse of the plurality of drive pulses is slower than the speed of the liquid ejected in the drive pulse immediately before the final drive pulse. ,
The drive pulse falls from an intermediate potential, and an expansion waveform element that expands the individual liquid chamber of the liquid ejection head,
Including a contraction waveform element that rises from the falling potential of the expansion waveform element to the intermediate potential, contracts the individual liquid chamber and discharges liquid,
Of the two drive pulses that are continuous in time series, the interval from the end point of the contraction waveform element of the previous drive pulse to the start point of the expansion waveform element of the subsequent drive pulse is the first pulse interval, which is the first pulse interval. When the interval from the start point of the contraction waveform element of the drive pulse to the start point of the contraction waveform element of the drive pulse after that is the second pulse interval,
The second pulse interval between the final drive pulse and the immediately previous drive pulse is different from the natural vibration period Tc × n (n is an integer of 1 or more) of the head,
The second pulse interval between the drive pulses before the drive pulse immediately before is a natural vibration period Tc × n (n is an integer of 1 or more) of the head,
The first pulse interval between the final drive pulse and the immediately preceding drive pulse is longer than the first pulse interval of the drive pulses up to the immediately preceding drive pulse.

  According to the present invention, generation of mist can be reduced.

It is a plane explanatory view of a mechanism part in an example of a device which discharges a liquid concerning the present invention. FIG. FIG. 6 is a cross-sectional explanatory view in a direction (liquid chamber longitudinal direction) orthogonal to the nozzle array direction of an example of a liquid ejection head. Similarly, it is a cross-sectional explanatory view in the nozzle arrangement direction (liquid chamber short side direction). It is a block explanatory view of the control part of the device. 3 is a block diagram illustrating an example of a portion related to head drive control. FIG. It is an explanatory view of a drive waveform in a 1st embodiment of the present invention. It is an explanatory view with which operation explanation of the embodiment is offered. It is explanatory drawing of the drive waveform in 2nd Embodiment of this invention. It is explanatory drawing of the drive waveform in 3rd Embodiment of this invention. It is explanatory drawing of the drive waveform in 4th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. An example of a device for ejecting a liquid according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is an explanatory plan view of a mechanical portion of the apparatus, and FIG.

  This apparatus is a serial type apparatus and holds a carriage 3 movably in a main scanning direction by a guide mechanism such as a main guide member 1. The carriage 3 is reciprocally moved in the main scanning direction (carriage moving direction) by a main scanning motor 5, which constitutes a main scanning movement mechanism, via a timing belt 8 spanning between a driving pulley 6 and a driven pulley 7.

  The carriage 3 is equipped with two liquid ejection units 40A and 40B (which will be referred to as “liquid ejection unit 40” if not distinguished. The same applies to other members). The liquid ejecting unit 40 is configured by integrating a liquid ejecting head 41 as a liquid ejecting unit and a head tank 42 that supplies liquid to the liquid ejecting head 41.

  The liquid ejection head 41 has two nozzle rows in which a plurality of nozzles are arranged. One nozzle row of the head 41A of the liquid ejection unit 40A ejects a black (K) droplet, and the other nozzle row ejects a cyan (C) droplet. Further, one nozzle row of the head 41B of the liquid ejection unit 40B ejects a magenta (M) droplet, and the other nozzle row ejects a yellow (Y) droplet.

  It should be noted that as the liquid ejecting means, it is also possible to use one having a plurality of nozzle rows for ejecting droplets of each color in which a plurality of nozzles are arranged on the nozzle surface of one liquid ejecting head.

  The head tank 42 is configured to include a plurality of tank portions that correspond to the two nozzle rows of each head 41 and that pair two tank portions that store the liquids of the respective colors.

  A cartridge holder 51 to which a main tank (liquid cartridge) 50 (50y, 50m, 50c, 50k) containing liquid of each color is replaceably mounted is arranged on the apparatus body side.

  The cartridge holder 51 is provided with a liquid feed pump portion 52, and the liquid feed pump portion 52 from the main tank 50 feeds each color to the head portion 42 of each head tank 42 via a feed tube (also referred to as a liquid feed path) 56 of each color. Liquid is supplied.

  On the other hand, in order to convey the sheet material 10, it is provided with a conveyor belt 12 which is a conveying means for adsorbing the sheet material 10 and conveying it at a position facing the head 41 of the liquid ejection unit 40. The suction of the sheet material 10 by the transport belt 12 can be performed by electrostatic suction or air suction.

  The conveyor belt 12 is an endless belt, and is stretched between the conveyor roller 13 and the tension roller 14. The transport belt 12 is rotated in the sub-scanning direction by the sub-scanning motor 16 rotating the transport roller 13 via the timing belt 17 and the timing pulley 18.

  Further, on one side of the carriage 3 in the main scanning direction, a maintenance / recovery mechanism 20 for maintenance / recovery of the head 41 is arranged beside the transport belt 12. On the other side of the carriage 3 in the main scanning direction, an idle ejection receiver 81 for receiving a liquid to be preliminarily ejected (idle ejection) from the head 41 is arranged beside the transport belt 12.

  The maintenance / recovery mechanism 20 is composed of, for example, a suction cap 21 that caps the nozzle surface 41a of the head 41, a moisturizing cap 22, a wiper member 23 that wipes the nozzle surface 41a, and an idle ejection receiver 24 that receives an idle ejection liquid. There is. The idle discharge may be performed on the suction cap 21.

  In addition, an encoder scale 123 having a predetermined pattern is stretched between both side plates along the main scanning direction of the carriage 3, and an encoder sensor 124 formed of a transmissive photo sensor for reading the pattern of the encoder scale 123 is provided on the carriage 3. It is provided. The encoder scale 123 and the encoder sensor 124 form a linear encoder (main scanning encoder) that detects the movement of the carriage 3.

  A code wheel 125 is attached to the shaft of the transport roller 13, and an encoder sensor 126, which is a transmissive photo sensor for detecting the pattern formed on the code wheel 125, is provided. The code wheel 125 and the encoder sensor 126 constitute a rotary encoder (sub-scanning encoder) that detects the moving amount and moving position of the conveyor belt 12.

  In the apparatus configured as described above, the sheet material 10 is fed onto the conveyor belt 12 and adsorbed thereto, and is conveyed in the sub-scanning direction by the circulation movement of the conveyor belt 12.

  Therefore, by moving the carriage 3 in the main scanning direction and driving the head 41 in accordance with the image signal, the liquid is ejected onto the stopped sheet material 10 to record one line. Then, after the sheet material 10 is conveyed by a predetermined amount, the next row is recorded.

  Upon receiving a recording end signal or a signal that the trailing edge of the sheet material 10 has reached the recording area, the printing operation is terminated and the sheet material 10 is discharged to a discharge tray (not shown).

  Next, an example of the liquid ejection head will be described with reference to FIGS. 3 and 4. 3 is a cross-sectional explanatory view in a direction (liquid chamber longitudinal direction) orthogonal to the nozzle array direction of the same head, and FIG. 4 is a cross-sectional explanatory view in the nozzle array direction (liquid chamber short-side direction).

  In this liquid ejection head, a nozzle plate 101, a flow path plate 102, and a vibrating plate member 103 are joined together. The piezoelectric actuator 111 for displacing the diaphragm member 103 and the frame member 120 as a common flow path member are provided.

  As a result, an individual liquid chamber (also referred to as a pressure chamber, a pressurizing chamber, etc.) 106 that communicates with the plurality of nozzles 104 that eject droplets, and a liquid supply that also serves as a fluid resistance portion that supplies the liquid to the individual liquid chamber 106. A passage 107 and a liquid introduction portion 108 communicating with the liquid supply passage 107 are formed. Adjacent individual liquid chambers 106 are separated by a partition wall 106A in the nozzle arrangement direction.

  Then, the liquid is supplied from the common liquid chamber 110 serving as the common flow path of the frame member 120 to the plurality of individual liquid chambers 106 through the liquid introduction portion 108 and the liquid supply passage 107 through the filter portion 109 formed on the diaphragm member 103. ..

  The piezoelectric actuator 111 is arranged on the opposite side of the individual liquid chamber 106 with the deformable vibration region 130 forming the wall surface of the individual liquid chamber 106 of the vibrating plate member 103 interposed therebetween.

  The piezoelectric actuator 111 has a plurality of laminated piezoelectric members 112 bonded on a base member 113. Grooves are formed in the piezoelectric member 112 by half-cut dicing, and columnar piezoelectric elements (piezoelectric columns) 112A that give a drive waveform and columns 112B are formed in a comb shape at a predetermined interval.

  The piezoelectric element 112A is bonded to the island-shaped convex portion 103a formed in the vibration region 130 of the diaphragm member 103. Further, the column 112B is joined to the convex portion 103b of the diaphragm member 103.

  The piezoelectric member 112 is formed by alternately stacking piezoelectric layers and internal electrodes. The internal electrodes are provided on the end faces of the piezoelectric members 112 and external electrodes are provided, and a piezoelectric element 112A is provided with a drive waveform for applying a drive waveform to the external electrodes. The FPC 115 as a flexible wiring board having flexibility is connected.

  A common liquid chamber 110 to which the liquid is supplied from the head tank 42 is formed in the frame member 120.

  In this liquid ejection head, for example, by lowering the voltage applied to the piezoelectric element 112A from the intermediate potential, the piezoelectric element 112A contracts, the vibrating region 130 of the vibrating plate member 103 descends, and the volume of the individual liquid chamber 106 expands. As a result, the liquid flows into the individual liquid chamber 106.

  After that, the voltage applied to the piezoelectric element 112A is increased to expand the piezoelectric element 112A in the stacking direction, deform the vibrating region 130 of the vibrating plate member 103 in the nozzle 104 direction, and contract the volume of the individual liquid chamber 106. As a result, the liquid in the individual liquid chamber 106 is pressurized, and the liquid is ejected (jetted) from the nozzle 104.

  Then, by returning the voltage applied to the piezoelectric element 112A to the intermediate potential, the vibration region 130 of the diaphragm member 103 is restored to the initial position. As a result, the individual liquid chamber 106 expands and a negative pressure is generated, so that the individual liquid chamber 106 is filled with the liquid from the common liquid chamber 110 through the liquid supply path 107. Therefore, after the vibration of the meniscus surface of the nozzle 104 is attenuated and stabilized, the operation for the next ejection is started.

  Next, an outline of the control unit of this device will be described with reference to FIG. FIG. 5 is a block diagram of the control unit.

  The control unit 500 includes a CPU 501 that controls the entire apparatus, a ROM 502 that stores fixed data such as various programs including programs executed by the CPU 501, and a main control unit 500A that includes a RAM 503 that temporarily stores image data and the like. ing.

  The control unit 500 includes a rewritable non-volatile memory 504 for holding data even when the power of the device is cut off. The control unit 500 includes an ASIC 505 that processes various signal processing for image data, image processing for rearranging, and other input / output signals for controlling the entire apparatus.

  The control unit 500 includes a print control unit 508 including a data transfer unit for driving and controlling the liquid ejection head 41 and a drive signal generating unit, and a drive IC for driving the liquid ejection head 41 (herein referred to as “head driver”). .) 509.

  The control unit 500 is connected to the main scanning motor 5 for moving and scanning the carriage 3, the sub-scanning motor 16 for moving the conveyor belt 12 in an orbit, the caps 21 and 22 of the maintenance / recovery mechanism 20, the movement of the wiper member 23, and the cap 21. A motor drive unit 510 for driving a maintenance / recovery motor 556 for driving the suction means is provided.

  The control unit 500 includes a supply system drive unit 512 that drives the liquid feed pump 54 of the liquid feed pump unit 52.

  The control unit 500 has an I / O unit 513. The I / O unit 513 can process various sensor information and acquires information from various sensor groups 515 mounted on the device. Then, information necessary for controlling the apparatus is extracted and used for controlling the print control unit 508 and the motor drive unit 510. The sensor group 515 includes an optical sensor for detecting the position of the sheet material 10 and an interlock switch for detecting opening / closing of the cover.

  An operation panel 514 for inputting and displaying information necessary for this apparatus is connected to the control unit 500.

  Here, the control unit 500 has an I / F 506 for transmitting and receiving data and signals to and from the host side, and from the information processing apparatus such as a personal computer, the host 600 side such as an image reading apparatus, a cable or a network. It is received by the I / F 506 via.

  Then, the CPU 501 of the control unit 500 reads out and analyzes the print data in the reception buffer included in the I / F 506, performs necessary image processing, data rearrangement processing, and the like in the ASIC 505, and print-controls this image data. Transfer from the unit 508 to the head driver 509. Note that the dot pattern data for outputting an image can be generated by the printer driver 601 on the host 600 side or by the control unit 500.

  The print control unit 508 transfers the image data as serial data, and outputs a transfer clock, a latch signal, a control signal, and the like necessary for transferring the image data and confirming the transfer to the head driver 509.

  The print control unit 508 includes a drive waveform generation unit including a D / A converter that performs D / A conversion of drive waveform pattern data, a voltage amplifier, and a current amplifier. Then, the print control unit 508 generates a drive waveform including a plurality of drive signals (drive pulses) in time series and outputs the drive waveform to the head driver 509.

  The head driver 509 selects a drive pulse that forms a drive waveform provided from the print control unit 508 based on image data corresponding to one row of the liquid ejection head 41 that is serially input, and selects the pressure of the liquid ejection head 41. It is given to the piezoelectric element 112A as a generating means. This drives the liquid ejection head 41.

  At this time, all or a part of a plurality of drive signals forming the drive waveform (a part of the waveform elements forming the drive signal) is selected. As a result, it is possible to eject dots of different sizes, such as large drops, medium drops, and small drops.

  Next, an example of a portion related to head drive control will be described with reference to the block diagram of FIG.

  The print control unit 508 includes a drive waveform generation unit 701 as a drive waveform generation device according to the present invention. In addition, data transfer that outputs 2-bit image data (gradation signals 0 and 1) corresponding to the print image and a selection signal (drop control signal) that selects a clock signal, a latch signal, and a drive pulse forming a drive waveform. The unit 702 is included.

  Here, the drive waveform generation unit 701 generates and outputs a drive waveform PV in which a plurality of drive pulses (drive signals) for ejecting the liquid are arranged in time series within one printing cycle (one drive cycle).

  The selection signal is a signal for instructing the opening and closing of the analog switch AS, which is the switch means of the head driver 509, for each droplet. The drive pulse (or the waveform element) to be selected according to the printing cycle of the drive waveform PV transits to H level (ON), and when not selected, transits to L level (OFF).

  The head driver 509 includes a shift register 711, a latch circuit 712, a decoder 713, a level shifter 714, and an analog switch array 715.

  The shift register 711 inputs a transfer clock (shift clock) and serial image data (gradation data: 2 bits / 1 channel (1 nozzle)) from the data transfer unit 702. The latch circuit 712 is a register of the shift register 711. The value is latched by the latch signal.

  The decoder 713 decodes the grayscale data and the selection signal and outputs the result. The level shifter 714 converts the logic level voltage signal of the decoder 713 into a level at which the analog switch AS of the analog switch array 715 can operate.

  The analog switch AS of the analog switch array 715 is turned on / off (opened / closed) by the output of the decoder 713 provided via the level shifter 714.

  The analog switch AS of the analog switch array 715 is connected to the individual electrode of the piezoelectric element 112A, and the drive waveform PV from the drive waveform generation unit 701 is input. Therefore, the analog switch AS is turned on according to the result of decoding the serially transferred image data (gradation data) and the selection signal by the decoder 713. As a result, a drive pulse (or a waveform element) that is a required drive signal forming the drive waveform PV passes (is selected) and is given to the individual electrode of the piezoelectric element 112A.

  Next, a first embodiment of the present invention will be described with reference to FIG. FIG. 7 is an explanatory diagram of drive waveforms in the same embodiment.

  The drive waveform PV is composed of drive pulses P1, P2, P3, and P4, which are drive signals, in time series. The drive pulse P4 is the final drive pulse, and the drive pulse P3 is the immediately preceding drive pulse. The number of drive pulses may be two or more, and is not limited to four (the same applies to the following).

  Each of the drive pulses P1 to P4 is a single pulse including an expansion waveform element (pull-in waveform element) a, a holding waveform element b, and a contraction waveform element (push-in waveform element) c. For simplification of the drawing, reference signs a to c are added only to the drive pulse P1, but other drive pulses P2 to P4 are also the same. Further, the number of drive pulses may be two or more and is not limited to four.

  The expansion waveform element a falls from the intermediate potential Vm and expands the individual liquid chamber 106. The holding waveform element b holds the falling potential of the expansion waveform element a for a certain period of time. The contraction waveform element c rises from the potential held by the holding waveform element b (falling potential due to the expansion waveform element a) to the intermediate potential Vm, contracts the individual liquid chamber 106, and ejects the liquid.

  Here, when the potential difference between the rising start potential due to the contraction waveform element c and the intermediate potential Vm, that is, the potential difference between the intermediate potential Vm and the falling potential due to the expansion waveform element a is the peak value, the immediately preceding drive pulse P3 has the peak value. Va, and the final drive pulse P4 has a peak value Vb (Vb <Va) smaller than the peak value Va. The drive pulses P1 and P2 are also set to the peak value Va.

  In this case, the peak value Vb of the final drive pulse P4 is a speed at which a microdroplet is not generated together with the main droplet upon ejection, and is higher than the speed of the microdroplet generated upon ejection by the immediately preceding drive pulse P3. It is set to a value that ejects drops at a speed.

  Further, when the time from the end point of the contraction waveform element c of the previous drive pulse to the start point of the expansion waveform element a of the subsequent drive pulse of the two consecutive drive pulses is the first pulse interval, the drive pulse The same interval Td1 is set between P1 and P2, P2 and P3, and P3 and P4.

  In addition, when the time from the start point of the contraction waveform element c of the preceding drive pulse to the start point of the contraction waveform element c of the subsequent drive pulse is the second pulse interval among the two consecutive drive pulses, the drive pulse is Between P1 and P2, between P2 and P3, and between P3 and P4, the natural vibration period of the head is Tc × n (n is an integer of 1 or more). In the present embodiment, n = 1 and the second pulse interval is the natural vibration period Tc.

  The operation of this embodiment will be described with reference to FIG. FIG. 8 is an explanatory diagram for explaining the same operation.

  First, as shown in FIGS. 8A to 8D, the droplets D1 to D4 are sequentially ejected by the drive pulses P1 to P4.

  Here, the velocities of the droplets D1 to D3 ejected by the drive pulses P1 to P3 have the same crest value and the second pulse interval is the natural vibration period Tc, so that the relationship of D1 <D2 <D3 is satisfied.

  As a result, as shown in FIG. 8E, the droplet D3 catches up with the preceding droplets D1 and D2 during flight and merges (merges) to form one droplet D11.

  Here, the minute droplet M1 is generated together with the droplet D3 (main droplet) by the immediately preceding drive pulse P3. At this time, the speed of the droplet D4 due to the drive pulse P4 is faster than the speed of the microdroplet M1, and therefore the microdroplet M1 is merged with the subsequent drop D4, as shown in FIGS. 8F and 8G. Do not scatter.

  Since the peak value Vb of the final drive pulse P4 is smaller than the peak value Va of the immediately preceding drive pulse P3, the drop D4 does not catch up with the preceding drop D11, as shown in FIG. The droplet D11 is landed at substantially the same position with respect to 10a to form one dot.

  By using such a drive waveform, the occurrence of mist can be reduced.

  Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 9 is an explanatory diagram of drive waveforms in the same embodiment.

  The drive waveform PV is composed of drive pulses P1, P2, P3, and P4, which are drive signals, in time series. The drive pulse P4 is the final drive pulse, and the drive pulse P3 is the immediately preceding drive pulse.

  In the present embodiment, all the drive pulses P1 to P4 have the same peak value Va.

  The first pulse interval between the drive pulses P1 and P2 and P2 and P3 is the same as the interval Td1. On the other hand, the first pulse interval between the final drive pulse P4 and the immediately previous drive pulse P3 is set to the interval Td2 (Td2> Td1).

  The second pulse interval between the drive pulses P1 and P2 and P2 and P3 is the natural vibration period Tc. On the other hand, the second pulse interval between the final drive pulse P4 and the immediately previous drive pulse P3 is the interval Te (Te> Tc).

  In this way, the first pulse interval between the final drive pulse P4 and the immediately preceding drive pulse P3 is set to the interval Td2, and the second pulse interval is deviated from the natural vibration period Tc. The speed of the droplet 3 can be slower than the speed of the immediately preceding drive pulse P3.

  Therefore, the speed of the droplets ejected by the final drive pulse P4 is a speed at which minute droplets are not generated together with the main droplets due to ejection, and is faster than the speed of minute droplets caused by ejection by the immediately preceding drive pulse P3. It has a high speed.

  Thereby, similarly to the first embodiment, the generation of mist can be suppressed.

  Further, since the voltage value of the drive waveform PV can be fixed, it is possible to easily cope with a binary drive pulse composed of a single pulse or a rectangular wave.

  Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 10 is an explanatory diagram of drive waveforms in the same embodiment.

  The drive waveform PV is composed of drive pulses P1, P2, P3, and P4, which are drive signals, in time series. The drive pulse P4 is the final drive pulse, and the drive pulse P3 is the immediately preceding drive pulse.

  In the present embodiment, the crest values of the drive pulses P1 to P4 are the same as the crest value Va.

  In addition, the first pulse intervals between the drive pulses P1 and P2, P2 and P3 are the same as the interval Td1. On the other hand, the first pulse interval between the final drive pulse P4 and the immediately previous drive pulse P3 is set to the interval Td3 (Td3 <Td1). That is, the first pulse interval between the final drive pulse and the immediately previous drive pulse is set longer than the first pulse interval of the drive pulses up to the immediately previous drive pulse.

  The second pulse interval between the drive pulses P1 and P2 and P2 and P3 is the natural vibration period Tc. On the other hand, the second pulse interval between the final drive pulse P4 and the immediately previous drive pulse P3 is set to the interval Tf (Tf <Tc), which is different from the natural vibration period Tc.

  In this way, the first pulse interval between the final drive pulse P4 and the immediately preceding drive pulse P3 is set to the interval Td3, and the first pulse interval is different from the natural vibration period Tc. The speed of the droplet can be made slower than the speed of the immediately preceding drive pulse P3.

  Therefore, the speed of the droplets ejected by the final drive pulse P4 is a speed at which minute droplets are not generated together with the main droplets due to ejection, and is faster than the speed of minute droplets caused by ejection by the immediately preceding drive pulse P3. It has a high speed.

  Thereby, similarly to the first embodiment, the generation of mist can be suppressed.

  Further, since the voltage value of the drive waveform PV can be fixed, it is possible to easily cope with a binary drive pulse composed of a single pulse or a rectangular wave.

  Furthermore, since the waveform length of the entire drive waveform can be made shorter than in the first and second embodiments, the number of drive weeks can be increased.

  Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 11 is an explanatory diagram of drive waveforms in the same embodiment.

  The drive waveform PV is composed of drive pulses P1, P2, P3, and P4, which are drive signals, in time series. The drive pulse P4 is the final drive pulse, and the drive pulse P3 is the immediately preceding drive pulse.

  In the present embodiment, the drive pulse P1 has a peak value Va1, the drive pulse P2 has a peak value Va2 (Va2> Va1), the drive pulse P3 has a peak value Va3 (Va3> Va2), and the drive pulse P4 has a peak value Vb (Vb <Va1). ).

  Further, the first pulse intervals between the drive pulses P1 and P2, P2 and P3, P3 and P4 are all set to the interval Td3 (Td3 <Td1).

  Further, the second pulse intervals between the drive pulses P1 and P2, P2 and P3, P3 and P4 are all set to the interval Tf (Tf <Tc), which is different from the natural vibration period Tc.

  In this way, since the crest values of the drive pulses P1 to P3 are successively increased, even if the second pulse interval deviates from the natural vibration period Tc, the speed of the drops is sequentially increased as in the first embodiment. Get faster Therefore, as in the first embodiment, the droplets ejected by the drive pulses P1 to P3 coalesce during flight.

  Further, since the crest value of the drive pulse P4 is smaller than the crest value of the drive pulse P3, the speed of the droplet caused by the drive pulse P4 can be made slower than the speed of the droplet caused by the immediately preceding drive pulse P3.

  Therefore, the speed of the droplets ejected by the final drive pulse P4 is a speed at which minute droplets are not generated together with the main droplets due to ejection, and is faster than the speed of minute droplets caused by ejection by the immediately preceding drive pulse P3. It has a high speed.

  Thereby, similarly to the first embodiment, the generation of mist can be suppressed.

  Since the waveform length of the entire drive waveform can be made shorter than that of the first to third embodiments, the drive frequency can be increased.

  In the present application, the liquid to be ejected is not particularly limited as long as it has a viscosity and a surface tension that can be ejected from the head, but the viscosity becomes 30 mPa · s or less at room temperature and normal pressure, or by heating and cooling. It is preferably one. More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, functional compounds such as polymerizable compounds, resins and surfactants, biocompatible materials such as DNA, amino acids, proteins and calcium. , Solutions, suspensions, emulsions, etc. containing edible materials such as natural pigments, etc., such as ink-jet inks, surface treatment solutions, components of electronic devices and light-emitting devices, and formation of electronic circuit resist patterns. It can be used for applications such as a working fluid and a three-dimensional modeling material fluid.

  Piezoelectric actuators (multilayer piezoelectric element and thin-film piezoelectric element), thermal actuators that use electrothermal conversion elements such as heating resistors, electrostatic actuators that consist of a diaphragm and counter electrode, etc. are used as the energy generation source that ejects liquid What you do is included.

  Further, the “apparatus for ejecting liquid” includes not only an apparatus capable of ejecting a liquid to which a liquid can be attached, but also an apparatus ejecting the liquid toward the air or into the liquid. ..

  This "device for ejecting liquid" can include a means for feeding, carrying, and discharging paper to which liquid can be attached, as well as a pretreatment device, a posttreatment device, and the like.

  For example, an "apparatus for ejecting a liquid" is an image forming apparatus that ejects ink to form an image on a sheet, and a powder is formed in layers to form a three-dimensional object (three-dimensional object). There is a three-dimensional modeling apparatus (three-dimensional modeling apparatus) that discharges the modeling liquid to the formed powder layer.

  Further, the “device for ejecting liquid” is not limited to a device in which a significant image such as characters and figures is visualized by the ejected liquid. For example, it also includes ones that form patterns and the like that have no meaning per se, and ones that form a three-dimensional image.

  The above-mentioned "liquid can be adhered" means a liquid to which a liquid can be at least temporarily adhered, which is adhered and fixed, and which is adhered and permeated. Specific examples include recording media such as paper, recording paper, recording paper, film and cloth, electronic substrates, electronic components such as piezoelectric elements, powder layers (powder layers), organ models, inspection cells and other media. Yes, and unless otherwise specified, includes anything to which liquid adheres.

  The material of the above-mentioned "liquid can be adhered" may be paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, etc. as long as the liquid can be adhered even temporarily.

  Further, the “device for ejecting liquid” includes a device in which the liquid ejection head and the device to which the liquid can be attached move relatively, but the device is not limited to this. Specific examples include a serial type device that moves the liquid discharge head, a line type device that does not move the liquid discharge head, and the like.

  Further, as the "apparatus for ejecting liquid", a treatment liquid application device for ejecting the treatment liquid onto the paper in order to apply the treatment liquid to the surface of the paper for the purpose of modifying the surface of the paper, and the like. There is an injection granulation device in which a composition liquid in which raw materials are dispersed in a solution is jetted through a nozzle to granulate fine particles of the raw materials.

  In the terms of the present application, image formation, recording, printing, printing, printing, modeling, etc. are synonymous.

40 Liquid Ejection Unit 41 Liquid Ejection Head (Head)
106 individual liquid chamber 500 control unit 502 printing control unit 701 drive waveform generation unit 702 data transfer unit

Claims (5)

A device for generating a drive waveform including a plurality of drive pulses in time series for ejecting liquid from a liquid ejection head,
The drive waveform is a waveform in which the speed of the liquid ejected in the final drive pulse of the plurality of drive pulses is slower than the speed of the liquid ejected in the drive pulse immediately before the final drive pulse. ,
The drive pulse falls from an intermediate potential, and an expansion waveform element that expands the individual liquid chamber of the liquid ejection head,
Including a contraction waveform element that rises from the falling potential of the expansion waveform element to the intermediate potential, contracts the individual liquid chamber and discharges liquid,
Of the two drive pulses that are continuous in time series, the interval from the end point of the contraction waveform element of the previous drive pulse to the start point of the expansion waveform element of the subsequent drive pulse is the first pulse interval, which is the first pulse interval. When the interval from the start point of the contraction waveform element of the drive pulse to the start point of the contraction waveform element of the drive pulse after that is the second pulse interval,
The second pulse interval between the final drive pulse and the immediately previous drive pulse is different from the natural vibration period Tc × n (n is an integer of 1 or more) of the head,
The second pulse interval between the drive pulses before the drive pulse immediately before is a natural vibration period Tc × n (n is an integer of 1 or more) of the head,
The drive waveform generation device, wherein the first pulse interval between the final drive pulse and the immediately previous drive pulse is longer than the first pulse interval of the drive pulses up to the immediately previous drive pulse. A device for generating a drive waveform including a plurality of drive pulses in time series for ejecting liquid from a liquid ejection head,
The drive waveform is a waveform in which the speed of the liquid ejected in the final drive pulse of the plurality of drive pulses is slower than the speed of the liquid ejected in the drive pulse immediately before the final drive pulse. ,
The drive pulse falls from an intermediate potential, and an expansion waveform element that expands the individual liquid chamber of the liquid ejection head,
Including a contraction waveform element that rises from the falling potential of the expansion waveform element to the intermediate potential, contracts the individual liquid chamber and discharges liquid,
Of the two continuous drive pulses in time series, the interval from the end point of the contraction waveform element of the previous drive pulse to the start point of the expansion waveform element of the subsequent drive pulse is the first pulse interval, When the interval from the start point of the contraction waveform element of the drive pulse to the start point of the contraction waveform element of the drive pulse after that is the second pulse interval,
The second pulse interval between the final drive pulse and the immediately previous drive pulse is different from the natural vibration period Tc × n (n is an integer of 1 or more) of the head,
The second pulse interval between the drive pulses before the drive pulse immediately before is a natural vibration period Tc × n (n is an integer of 1 or more) of the head,
The drive waveform generation device, wherein the first pulse interval between the final drive pulse and the immediately preceding drive pulse is shorter than the first pulse interval of the drive pulses up to the immediately preceding drive pulse. A device for generating a drive waveform including a plurality of drive pulses in time series for ejecting liquid from a liquid ejection head,
The drive waveform is a waveform in which the speed of the liquid ejected in the final drive pulse of the plurality of drive pulses is slower than the speed of the liquid ejected in the drive pulse immediately before the final drive pulse. ,
The drive pulse falls from an intermediate potential, and an expansion waveform element that expands the individual liquid chamber of the liquid ejection head,
Including a contraction waveform element that rises from the falling potential of the expansion waveform element to the intermediate potential, contracts the individual liquid chamber and discharges liquid,
When the potential difference between the intermediate potential and the rising start potential of the contraction waveform element is a peak value,
Among the plurality of drive pulses, the peak value of the immediately preceding drive pulse is the largest,
The peak value of the final drive pulse is smaller than the peak value of the immediately preceding drive pulse,
Of the two drive pulses that are continuous in time series, the interval from the end point of the contraction waveform element of the previous drive pulse to the start point of the expansion waveform element of the subsequent drive pulse is the first pulse interval, which is the first pulse interval. When the interval from the start point of the contraction waveform element of the drive pulse to the start point of the contraction waveform element of the drive pulse after that is the second pulse interval,
Between the plurality of drive pulses, the second pulse interval is different from the natural vibration cycle Tc × n (n is an integer of 1 or more) of the head,
The drive waveform generation device, wherein the first pulse intervals are the same among the plurality of drive pulses. A device for generating a drive waveform including a plurality of drive pulses in time series for ejecting liquid from a liquid ejection head,
The drive waveform is a waveform in which the speed of the liquid ejected in the final drive pulse of the plurality of drive pulses is slower than the speed of the liquid ejected in the drive pulse immediately before the final drive pulse. ,
The speed of the liquid ejected by the immediately preceding drive pulse is the speed at which minute droplets are generated along with the main droplet,
The velocity of the liquid ejected by the final drive pulse is a velocity that does not generate the microdroplets, and is faster than the velocity of the microdroplets generated by the ejection by the immediately previous drive pulse. The drive waveform generation device according to any one of 1 to 5. Apparatus for ejecting liquid, characterized in that it comprises a driving waveform generating device according to any one of claims 1 to 4.

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