JP5265495B2 - Inkjet recording apparatus and image processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately correct a driving waveform applied to a piezoelectric element to become constant even if the number of nozzles for simultaneously discharging an ink droplet varies. <P>SOLUTION: A memory 73 memorizes a reference correction voltage &Delta;Va and a reference current consumption Ia beforehand for each number of nozzle N, and outputs the reference correction voltage &Delta;Va and the reference current consumption Ia to a multiplier 74 according to the number of nozzle N counted by a nozzle number counting part 72. A correction voltage &Delta;V is computed by the multiplier 74 using the reference correction voltage &Delta;Va and the reference current consumption Ia and a current consumption Ib which is measured by a current measuring part 80 and actually flows to a recording head. An adder 77 adds the correction voltage &Delta;V to the driving wave form that has been quantized. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an ink jet recording apparatus that forms an image on a sheet with ink droplets ejected from a nozzle, and an image processing apparatus mounted on such an ink jet recording apparatus.

  In recent years, many inkjet printers that form images by ejecting ink onto paper have become widespread. In such an ink jet printer, the sheets stored in the sheet cassette are fed out one by one, and the sheets are transported to a position facing the recording head for ejecting ink by a transport belt. When the paper reaches a position facing the recording head, ink droplets are ejected from the recording head toward the paper, and images are sequentially formed on the paper.

  The recording head has a configuration in which a plurality of ink ejection units having a pressurizing chamber communicating with a nozzle that is an ejection port for ejecting ink droplets and a piezoelectric element (piezo element) disposed on a wall surface of the pressurizing chamber are arranged. Is done. The piezoelectric element operates according to the supplied driving waveform, and the pressurizing chamber is always filled with ink. The ink filled in the pressurizing chamber is ejected as ink droplets from the nozzle in accordance with the operation of the piezoelectric element.

  In order to obtain high image quality in an image formed on paper, common conditions such as the same timing, the same discharge speed, and the same amount of ink droplets are required from all nozzles. However, in reality, the current consumption of the recording head varies depending on the variation in capacitance of individual piezoelectric elements and the number of nozzles that simultaneously eject ink droplets (that is, the number of piezoelectric elements to be driven). When the consumption current fluctuates in this way, the applied voltage to the recording head also changes, and the drive waveform supplied to the piezoelectric element also changes, so the amount of ink droplets changes and the image quality is not maintained. There was a problem.

  Therefore, in Patent Document 1, the relationship between the number of nozzles that simultaneously eject ink droplets and the DA converter output is stored in advance, and the drive voltage supplied to the piezoelectric element is determined according to the number of nozzles that eject ink droplets. A correction method using a DA converter and a DC-DC converter is described.

Japanese Patent Laid-Open No. 05-116342

  However, the method described in Patent Document 1 does not consider the current consumption of the recording head, which varies depending on the number of nozzles ejecting ink droplets at the same time, so that the drive voltage supplied to the piezoelectric element can be made completely constant. It wasn't.

  The present invention has been made to solve the above problem, and at the same time, even when the number of nozzles ejecting ink droplets changes, the drive waveform supplied to the piezoelectric element is accurately corrected. An object of the present invention is to provide an ink jet recording apparatus and an image processing apparatus.

An ink jet recording apparatus according to a first aspect of the present invention includes a pressurizing chamber for storing ink, and a piezoelectric element disposed on a wall surface of the pressurizing chamber, and the piezoelectric element according to a supplied driving waveform. Is activated to eject ink droplets from nozzles communicating with the pressurizing chamber, a recording head having a plurality of ink ejection means, and each ink based on input image data. Print data generating means for generating print data indicating the amount of ink droplets discharged from the discharge means; counting means for counting the number of nozzles that simultaneously discharge ink droplets from the generated print data; and Reference correction voltage storage means for storing a reference correction voltage set in advance for correcting the drive waveform according to the number of the nozzles that simultaneously eject ink droplets; and A reference drive waveform generating means for generating a reference drive waveform based on the character data, the number of the nozzles to eject a measuring means for measuring the current consumption of the recording head, the ink droplets simultaneously reference consumption current of the recording head In accordance with the reference consumption current storage means for storing the reference correction voltage and the reference correction voltage corresponding to the number of nozzles counted by the counting means from the reference correction voltage storage means, and according to the number of nozzles counted by the counting means Calculation means for taking in a reference consumption current from the reference consumption current storage means, calculating an actual correction voltage from the taken reference correction voltage and reference consumption current and the consumption current measured by the measurement means, and calculating by the calculation means actual correction voltage driving waveform generating means for outputting said each ink ejection means as said driving waveform by correcting the reference driving waveform with that A conveying means for conveying the sheet in a position facing the nozzle having said ink ejection means comprises, by ink droplets ejected from said ink ejection means forms an image on the paper.

According to a second aspect of the present invention, there is provided an image processing apparatus comprising: a print data generating unit that generates print data based on input image data; a pressurizing chamber that contains ink; and a wall surface of the pressurizing chamber. The piezoelectric element is disposed and driven to supply ink discharge means for discharging ink droplets from a nozzle communicating with the pressurizing chamber by operating the piezoelectric element in accordance with the supplied driving waveform. A drive waveform generating means for generating a waveform, a counting means for counting the number of the nozzles that simultaneously eject ink droplets from the print data generated by the print data generating means, and a preset for correcting the drive waveform A reference correction voltage storage means for storing the generated reference correction voltage according to the number of the nozzles that simultaneously eject ink droplets, and a reference drive waveform based on the print data is generated A reference driving waveform generating means, measuring means for measuring the current consumption of the recording head having a plurality of said ink ejection means, respectively in accordance with the number of the nozzles for ejecting ink droplets simultaneously reference consumption current of the recording head The reference consumption current storage means for storing and the reference correction voltage corresponding to the number of nozzles counted by the counting means are taken from the reference correction voltage storage means, and the reference consumption current corresponding to the number of nozzles counted by the counting means is obtained. The drive waveform generation means includes: a calculation means that takes in the reference consumption current storage means and calculates an actual correction voltage from the taken reference correction voltage and reference consumption current and the consumption current measured by the measurement means. the reference drive waveform after correcting the said correcting the reference driving waveform using the actual correction voltage said calculating means is calculated as the drive waveform Serial and outputs it to the respective ink discharging means.

  Here, since the consumption current of the recording head fluctuates due to the fluctuation of the number of nozzles that simultaneously eject ink droplets, the fluctuation of this consumption current is actually measured at the design stage of the inkjet recording apparatus or before factory shipment, A reference correction voltage is preset and stored based on the measurement result. That is, it is desirable that the value of the reference correction voltage is a value that takes into account the variation in the current consumption of the recording head due to the variation in the number of nozzles that simultaneously eject ink droplets.

  According to these configurations, by correcting the reference drive waveform using the reference correction voltage corresponding to the number of nozzles that simultaneously eject ink droplets, a stable drive waveform is supplied to the nozzle supply unit regardless of the number of nozzles. be able to. Therefore, even if the current consumption of the recording head changes due to the change in the number of nozzles that simultaneously eject ink droplets, the ink ejection amount can be kept constant and the image quality can be maintained.

  According to these configurations, by correcting the drive waveform using the reference correction voltage corresponding to the number of nozzles that simultaneously eject ink droplets or the reference consumption current of the recording head, a stable drive waveform can be obtained regardless of the number of nozzles. It can supply to a nozzle supply means. Therefore, even if the current consumption of the recording head changes due to the change in the number of nozzles that simultaneously eject ink droplets, the ink ejection amount can be kept constant and the image quality can be maintained. Furthermore, the actual consumption current of the recording head is measured, and the measured consumption current is used for correcting the drive waveform, so that it depends on the installation environment (temperature, humidity, etc.) of the inkjet recording apparatus and image processing apparatus, continuous printing time, etc. The drive waveform can be corrected according to the fluctuation of the current consumption of the recording head.

  According to the present invention, by correcting the reference drive waveform using the reference correction voltage corresponding to the number of nozzles that simultaneously eject ink droplets, a stable drive waveform is supplied to the nozzle supply unit regardless of the number of nozzles. Can do. Therefore, even if the current consumption of the recording head changes due to the change in the number of nozzles that simultaneously eject ink droplets, the ink ejection amount can be kept constant and the image quality can be maintained.

1 is a schematic sectional view of an ink jet printer. FIG. 3 is a plan view when the recording head and the belt unit are viewed from above. 1 is a block diagram showing an electrical configuration of an ink jet printer. The block diagram which showed the electric constitution of the drive control circuit. The figure which showed an example of the data structure of a reference | standard correction voltage memory | storage part. The figure which showed an example of the circuit structure of a current measurement part. The timing chart of the voltage correction by a drive control circuit. The figure which showed the reference | standard drive waveform and the drive waveform after correction | amendment.

  Hereinafter, embodiments of an ink jet recording apparatus and an image processing apparatus according to the present invention will be described with reference to the drawings. In the following embodiments, an inkjet printer alone will be described as an example of an inkjet recording apparatus. However, the inkjet recording apparatus according to the present invention can be applied to a copying machine, a facsimile, or an electronic apparatus such as a multifunction machine having these functions. . An ink jet printer that performs color printing using a plurality of recording heads will be described as an example, but an ink jet printer for monochromatic printing may be used.

  FIG. 1 is a schematic cross-sectional view of an inkjet printer 1 according to the present embodiment. The ink jet printer 1 includes a paper cassette 11, a pickup roller 12, a transport roller pair 13, a suction roller 14, a transport belt 15, a recording head 18, a cleaning device 21, a discharge roller pair 25, and a discharge tray 26.

  In the paper cassette 11, paper P before printing is stacked and stored. The paper P is picked up one by one by driving the pickup roller 12 and sent out to the conveyance path 31. The transport roller pair 13 transports the paper P that has passed through the transport path 31 to the transport path 32.

  The sheet P that has passed through the conveyance path 32 is conveyed to a position facing the ink discharge port of the recording head 18 via the nip portion between the suction roller 14 and the conveyance belt 15. The surface of the suction roller 14 is in contact with the transport belt 15, and the paper P is pressed against the transport belt 15 and sucked.

  For example, a dielectric resin sheet is used as the transport belt 15, and a (seamless) belt having no seam is mainly used. The conveyor belt 15 is stretched over a paper feed side (upstream side) driven roller 22, a paper discharge side (downstream side) drive roller 20, and a tension roller 19, and the drive roller 20 is counterclockwise on the paper surface. When rotating around, the conveyor belt 15 rotates in the direction of arrow Y, and the driven roller 22 and the tension roller 19 are driven by the conveyor belt 15 to rotate. The tension roller 19 is a roller for applying tension so that the conveying belt 15 does not sag between the driving roller 20 and the driven roller 22. Hereinafter, a portion constituted by the conveyor belt 15, the driven roller 22, the tension roller 19, the driving roller 20, the cleaning device 21, and the like is referred to as a “belt unit 100”.

  The recording head 18 includes, for example, a yellow recording head 18Y, a magenta recording head 18M, a cyan recording head 18C, and a black recording head 18K. Then, cyan, magenta, yellow, and black inks are ejected toward the paper P to sequentially form images. The ink ejection method of the recording head 18 in the present embodiment uses a piezo method in which ink is ejected from a nozzle using a piezoelectric element such as a piezo element.

  The cleaning device 21 is for removing ink adhering to the surface of the transport belt 15. The sheet P on which the image has been formed passes through the discharge conveyance path 24 and is discharged to the discharge tray 26 by the discharge roller pair 25.

  FIG. 2 is a plan view of the recording head 18 and the belt unit 100 as viewed from above. The recording head 18 is disposed from the upstream side toward the downstream side in the rotation direction along the circumferential direction (paper conveyance direction) of the conveyance belt 15. Each recording head 18 has a line head 51 extending in a direction perpendicular to the paper transport direction (paper width direction), and a plurality of nozzles for ejecting ink droplets on the lower surface of the line head 51. Is provided.

  Each nozzle provided in the line head 51 communicates with the pressurizing chamber, and a piezoelectric element (piezo element) is disposed on the wall surface of the pressurizing chamber. The piezoelectric element operates according to the supplied driving waveform, and the pressurizing chamber is always filled with ink. Therefore, the ink filled in the pressurizing chamber is ejected as ink droplets from the nozzle in accordance with the operation of the piezoelectric element. Each recording head 18 is equipped with a drive control circuit that selects a nozzle for ejecting ink droplets and supplies a drive waveform to a piezoelectric element corresponding to the selected nozzle.

  Here, in order to form an image with good image quality on the paper P, appropriate timing, the same ejection speed, and the same amount of ink droplets are ejected from all the nozzles provided in the line head 51. Common conditions are required. However, in practice, it is difficult to make the amount of ink droplets ejected from all the nozzles constant due to variations in accuracy of the piezoelectric elements and variations in the configuration of the recording head 18.

  In order to solve this problem, conventionally, a drive waveform that has been corrected in advance according to the characteristics of the piezoelectric element, the recording head 18 and the like is stored in a memory for each nozzle, so that the ink droplets discharged from the nozzles are stored. A method of correcting variation in quantity was used. However, in the case of a print head with a large number of nozzles, the number of drive waveform data to be stored increases accordingly, so a memory with a large storage capacity is required, and the drive control circuit mounted on the print head 18 can be reduced in size and cost. There was a problem in terms of

  Therefore, the present invention proposes a method capable of correcting the variation in the amount of ink droplets ejected from the nozzles even using a memory having a small storage capacity.

  FIG. 3 is a block diagram showing an electrical configuration of the ink jet printer 1. The inkjet printer 1 includes a control unit 60, a storage unit 61, a paper transport unit 62, an image memory 63, an image processing unit 64, an image forming unit 65, an input operation unit 66, and a network I / F unit 67. .

  The control unit 60 is configured by a CPU (Central Processing Unit) or the like, reads a program stored in the storage unit 61 and executes processing, and outputs an instruction signal to each functional unit, data transfer, and the like. The overall control of the ink jet printer 1 is performed.

  The storage unit 61 stores programs, data, and the like for realizing various functions provided in the inkjet printer 1. The paper transport unit 62 includes the belt unit 100 and various rollers. The image memory 63 temporarily stores image data transmitted from an external device via the network I / F unit 67. The image processing unit 64 performs image processing such as image correction and enlargement / reduction on the image data stored in the image memory 63. The image forming unit 65 includes the recording head 18 and forms an image indicated by the image data on the sheet conveyed by the sheet conveying unit 62. The recording head 18 includes a drive control circuit 181 that supplies a drive waveform to the piezoelectric element to control ink droplets ejected from each nozzle. The drive control circuit 181 will be described in detail later.

  The input operation unit 66 includes a display panel for displaying various messages and operation buttons for inputting various operation commands such as a power key and a reset key. The network I / F unit 67 includes a communication module such as a LAN board, and transmits / receives various data to / from an external device via a network (not shown) connected to the network I / F unit 67.

  FIG. 4 is a block diagram showing an electrical configuration of the drive control circuit 181. The drive control circuit 181 includes a control unit 71, a nozzle number counting unit 72, a storage unit 73, a multiplier 74, a rectangular wave generation unit 75, a quantization unit 76, an adder 77, a DA converter (DAC) 78, an output unit 79, A resistor R0 and a current measuring unit 80 are provided.

  The control unit 71 performs overall control of the drive control circuit 181 by performing data transfer, output of instruction signals, and the like to each functional unit constituting the drive control circuit 181.

  When the printing cycle signal is output from the control unit 71, the nozzle number counting unit 72 takes in printing data (gradation data) and simultaneously calculates the number N of nozzles (N is an integer equal to or larger than 0) that ejects ink droplets. Count. The print cycle signal is intermittently output at predetermined intervals in consideration of the time required for ink ejection for one line of the line head 51.

  The storage unit 73 includes a pulse information storage unit 731, a reference correction voltage storage unit 732, and a reference consumption current storage unit 733. The pulse information storage unit 731 uses, as print data, pulse information (Ton: piezoelectric element on-time, Toff: piezoelectric element off-time, etc.) for generating a reference drive waveform that is the basis of the drive waveform supplied to the piezoelectric element 90. Each is memorized accordingly. The control unit 71 causes the pulse information storage unit 731 to read out pulse information corresponding to the print data and output it to the rectangular wave generation unit 75.

  The reference correction voltage storage unit 732 stores a reference correction voltage ΔVa used when calculating a correction voltage for the reference drive waveform generated by the rectangular wave generation unit 75 in association with the number N of nozzles. FIG. 5 is a diagram illustrating an example of a data configuration of the reference correction voltage storage unit 732.

  The reference consumption current storage unit 733 stores the reference consumption current Ia used when calculating the correction voltage for the reference drive waveform generated by the rectangular wave generation unit 75 in association with the number N of nozzles.

  When the number of nozzles that simultaneously eject ink droplets is N, the drive waveforms are supplied to the N piezoelectric elements 90 simultaneously. Since the piezoelectric element 90 includes capacitance, there is a problem that the current consumption of the recording head 18 varies depending on the number of piezoelectric elements 90 that are driven simultaneously, and the voltage at Toff becomes unstable. Therefore, a reference correction voltage ΔVa and a reference consumption current Ia to be corrected are set in advance for every N nozzles that simultaneously eject ink droplets, and a correction voltage that is actually added to the reference drive waveform is calculated using these values. Thus, a stable driving waveform irrespective of the number N of nozzles can be supplied to the piezoelectric element 90. The reference correction voltage ΔVa and the reference consumption current Ia are set by a measurement experiment or the like before shipment from the factory, and then stored in the storage unit 73.

  The rectangular wave generation unit 75 takes in the clock signal (CLK) output from the control unit 71 and the pulse information output from the storage unit 73, and generates a reference drive waveform. The quantization unit 76 quantizes (A / D conversion) the reference drive waveform output from the rectangular wave generation unit 75 and outputs a quantized value (approximate value).

  The adder 77 adds the correction voltage ΔV output from the multiplier 74 and the quantized value. The DAC 78 D / A converts the addition result output from the adder 77. The output unit 79 amplifies the value output from the DAC 78 and outputs it as a drive waveform for supplying to the piezoelectric element 90.

  The resistor R0 is a resistor provided between the output unit 79 and the piezoelectric element 90, and is a sufficiently small resistor. The current measuring unit 80 measures the consumption current Ib flowing through the recording head 18 based on the voltage value at the input end and the output end of the resistor R0.

  FIG. 6 is a diagram illustrating an example of a circuit configuration of the current measuring unit 80. The current measuring unit 80 includes buffer amplifiers 81 and 82, an operational amplifier 83, an ADC 84, a divider 85, and resistors R5, R6, R7, and R8. The buffer amplifier 81 inputs and amplifies the voltage at the input terminal of the resistor R0. The buffer amplifier 82 inputs and amplifies the voltage at the output terminal of the resistor R0. The operational amplifier 83 outputs the difference (Vs = V1−V2) between the voltage at the input end and the voltage at the output end of the resistor R0, and the ADC 84 A / D converts the voltage Vs. The divider 85 divides the A / D converted voltage Vs by the resistor R0 and outputs the result as the actual consumption current Ib in the recording head 18.

  The multiplier 74 takes in the reference correction voltage ΔVa and the reference consumption current Ia output from the storage unit 73, further takes in the actual consumption current Ib output from the current measurement unit 80, and uses these values to correct the correction voltage. ΔV is calculated. As an example of the calculation method, the multiplier 74 calculates a ratio (Ib / Ia) between the reference consumption current Ia and the actual consumption current Ib, and multiplies this ratio by the reference correction voltage ΔVa to calculate the correction voltage ΔV. The adder 77 adds the correction voltage ΔV to the quantized value output from the quantizing unit 76.

  FIG. 7 is a timing chart of voltage correction by the drive control circuit 181. When the control unit 71 outputs a print cycle signal at time t1, the control unit 71 outputs print data D1 after a predetermined time. While the print data D1 is being output (time T), the nozzle number counting unit 72 simultaneously counts the number N of nozzles that eject ink droplets. When the output of the print data D1 by the control unit 71 is completed, the nozzle number counting unit 72 outputs the counted nozzle number N1 to the storage unit 73. The storage unit 73 and the reference correction voltage ΔVa1 and the reference number corresponding to the nozzle number N are output. The consumption current Ia is output. (In actuality, the nozzle number counting unit 72 outputs the nozzle number N to the control unit 71, and the control unit 71 outputs the nozzle number N from the reference correction voltage storage unit 732 and the reference consumption current storage unit 733 based on the nozzle number N. The reference correction voltage ΔVa1 and the reference consumption current Ia are read out according to the above).

  Subsequently, the multiplier 74 calculates and outputs the correction voltage ΔV1 using the reference correction voltage ΔVa1, the reference consumption current Ia, and the actual consumption current Ib, and the adder 77 outputs the correction voltage ΔV1 and the reference drive waveform at the time of Toff. The voltage V0 is added to output V0 + ΔV1.

  FIG. 8 is a diagram showing the reference drive waveform and the corrected drive waveform. The reference driving waveform supplies the on / off voltage to the piezoelectric element 90 by being a voltage V0 at Toff and a GND level voltage at Ton. The piezoelectric element 90 operates according to the supplied voltage value.

  Here, when the correction voltage output from the multiplier 74 is ΔVn, the adder 77 corrects the reference drive waveform by adding ΔVn to the voltage V0 at the time of Toff. That is, the corrected driving waveform is a voltage V0 + ΔVn at Toff, and a GND level voltage at Ton.

  As described above, the reference correction voltage ΔVa and the reference consumption current Ia are stored in advance for each number of nozzles N, and the correction voltage ΔV is calculated using these values and the consumption current Ib that actually flows through the recording head 18. Thus, a stable driving waveform can be supplied to the piezoelectric element 90 regardless of the number N of nozzles.

  The present invention is not limited to the configuration of the above embodiment, and various modifications can be made. In the above embodiment, the consumption current Ib of the recording head 18 is measured using the resistor R0 and the current measuring unit 80, and the multiplier 74 uses the consumption current Ib, the reference correction voltage ΔVa, and the reference consumption current Ia to correct the correction voltage. Although ΔV is calculated, the adder 77 may directly take in the reference correction voltage ΔVa and add it to the reference drive waveform without measuring the consumption current Ib.

  In this case, the reference consumption current storage unit 733, the multiplier 74, the current measurement unit 80, and the resistor R0 are not necessary. At the same time, the current consumption of the recording head 18 fluctuates due to fluctuations in the number N of nozzles that eject ink droplets at the same time. Based on the measurement result, a reference correction voltage is set and stored in the reference correction voltage storage unit 733. That is, even when the reference drive waveform is corrected using only the reference voltage, the value of the reference correction voltage is a value that takes into account the fluctuation of the current consumption of the recording head 18 due to the fluctuation of the number N of nozzles that simultaneously eject ink droplets. It has become.

  However, in practice, the current consumption Ib of the recording head 18 may vary depending on the installation environment (temperature, humidity, etc.) of the inkjet printer 1 and the continuous printing time. It is desirable to use it as a correction factor when correcting the reference drive waveform.

1 Inkjet printer (inkjet recording device)
15 Conveying belt (conveying means)
18 Recording Head 181 Drive Control Circuit 65 Image Forming Unit 71 Control Unit (Print Data Generation Unit)
72 Nozzle number counting section (counting means)
73 storage unit 731 pulse information storage unit 732 reference correction voltage storage unit (reference correction voltage storage means)
733 Reference consumption current storage unit (reference consumption current storage means)
74 Multiplier (Calculation means)
75 Rectangular wave generator (reference drive waveform generator)
76 Quantization unit (drive waveform generation means)
77 Adder (drive waveform generating means)
78 DAC (drive waveform generation means)
79 Output unit (drive waveform generating means)
80 Current measuring section (measuring means)
90 Piezoelectric elements (ink ejection means)

Claims (2)

A pressure chamber containing ink; and a piezoelectric element disposed on a wall surface of the pressure chamber. The piezoelectric element is operated according to a supplied driving waveform to communicate with the pressure chamber. Ink ejection means for ejecting ink droplets from the nozzles,
A recording head having a plurality of ink ejection means;
Print data generating means for generating print data indicating the amount of ink droplets ejected from each ink ejecting means based on the input image data;
Counting means for counting the number of the nozzles that simultaneously eject ink droplets from the generated print data;
Reference correction voltage storage means for storing a reference correction voltage set in advance for correcting the drive waveform according to the number of the nozzles that simultaneously eject ink droplets,
Reference drive waveform generating means for generating a reference drive waveform based on the print data;
Measuring means for measuring current consumption of the recording head;
Reference consumption current storage means for storing the reference consumption current of the recording head according to the number of the nozzles that simultaneously eject ink droplets,
A reference correction voltage corresponding to the number of nozzles counted by the counting means is taken from the reference correction voltage storage means, and a reference current consumption corresponding to the number of nozzles counted by the counting means is taken from the reference consumption current storage means. Calculating means for calculating an actual correction voltage from the captured reference correction voltage and reference consumption current and the consumption current measured by the measurement means;
Drive waveform generation means for correcting the reference drive waveform using the actual correction voltage calculated by the calculation means and outputting the corrected drive waveform to the ink ejection means;
Transport means for transporting paper to a position facing the nozzles of the ink ejection means;
And an ink jet recording apparatus that forms an image on the paper with ink droplets ejected from the ink ejection means. Print data generation means for generating print data based on the input image data;
A pressure chamber containing ink; and a piezoelectric element disposed on a wall surface of the pressure chamber. The piezoelectric element is operated according to a supplied driving waveform to communicate with the pressure chamber. Drive waveform generating means for generating a drive waveform to be supplied to the ink discharge means for discharging ink droplets from the nozzles being disposed;
Counting means for counting the number of nozzles that simultaneously eject ink droplets from the print data generated by the print data generating means;
Reference correction voltage storage means for storing a reference correction voltage set in advance for correcting the drive waveform according to the number of the nozzles that simultaneously eject ink droplets,
Reference drive waveform generating means for generating a reference drive waveform based on the print data;
Measuring means for measuring current consumption of a recording head having a plurality of the ink ejection means;
Reference consumption current storage means for storing the reference consumption current of the recording head according to the number of the nozzles that simultaneously eject ink droplets,
A reference correction voltage according to the number of nozzles counted by the counting means is taken from the reference correction voltage storage means, and a reference consumption current according to the number of nozzles counted by the counting means is taken from the reference consumption current storage means. Calculating means for calculating an actual correction voltage from the captured reference correction voltage and reference consumption current and the consumption current measured by the measurement means;
The drive waveform generation means corrects the reference drive waveform using the actual correction voltage calculated by the calculation means, and outputs the corrected reference drive waveform as the drive waveform to the ink ejection means. An image processing apparatus.

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