JP2007030193A - Inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recorder which can solve a positional shift of a recording position of ink on a recording medium brought about by a secular change of ink nature or the like, a change of a carriage speed, etc., by a uniform method, and moreover which can solve the positional shift easily and correctly. <P>SOLUTION: The inkjet recorder 1 of a serial system is equipped with a head position detector 24 capable of detecting a position of a recording head 11 to the recording medium S, a controller 20 which makes ink ejected on the basis of a set recording condition and position information of the recording head 11, a recording position detector 13 capable of detecting the recording position of ink struck on the recording medium, and a corrector 25 which calculates an emission speed v<SB>0</SB>sinθ<SB>0</SB>of the ejected ink on the basis of an interval L between the recording positions Q<SB>a</SB>and Q<SB>b</SB>of the ink when the ink is ejected under different conditions from the recording head 11, and which carries out correction of the recording condition set to the controller 20 on the basis of the calculated emission speed v<SB>0</SB>sinθ<SB>0</SB>of the ink. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to a serial head type ink jet recording apparatus capable of correcting a positional deviation of an ink recording position.

  An ink jet recording apparatus that records an image or the like on a recording medium by ejecting and landing ink on the recording medium from a nozzle of a recording head, that is, an ink jet recording apparatus is not only paper or fabric, but also a resin film or metal Since recording can be performed even on a recording medium having poor ink absorbability such as a plate, its application range is expanded in various fields today.

  In this ink jet recording apparatus, in particular, in a serial head type ink jet recording apparatus that performs recording while the recording head moves in the main scanning direction on the recording medium, the recording head is arranged so that ink is landed at the same recording position on the recording medium. In spite of the control of ejecting ink from the ink, there may be a problem of so-called misregistration of the recording position in which the recording position is shifted without the ink landing on the same recording position.

  For example, as shown in FIGS. 20 (A) and 20 (B), the positional deviation of the ink recording position is caused by a forward operation and a backward operation from the recording head 100 that reciprocates in the main scanning direction in a serial head type ink jet recording apparatus. Occasionally occurs when performing so-called bidirectional recording, in which ink is ejected to the recording medium.

  That is, as shown in FIG. 20 (A), the ink discharge timing from the recording head 100 is too early and the ink lands on the recording medium S before the original recording position, or as shown in FIG. 20 (B). When the ejection timing is too late and the ink reaches the original recording position, the ink recording position shifts.

  In addition, such a displacement of the recording position can occur between a plurality of recording heads. That is, as shown in FIG. 21A, after the ink is ejected and landed on the recording medium S from the recording head 100a that is positioned forward in the moving direction among the recording heads 100a and 100b that move in the same direction, FIG. As shown in (B), even if ink is ejected from the recording head 100b at the rear in the moving direction so as to land the ink at the same recording position, the recording position may be displaced without landing at the same recording position. is there.

  Note that the displacement of the recording position of the ink as shown in FIG. 21 is not only the case of the bidirectional recording described above, but also a so-called one-sided ink that ejects ink only during the forward operation of the recording head that reciprocates in the main scanning direction. It also occurs when performing direction recording.

  When such a position shift occurs in the ink recording position on the recording medium, the recording quality on the recording medium deteriorates. Accordingly, various methods have been devised in order to prevent the occurrence of such displacement of the ink recording position.

  For example, when the recording head is replaced, an index indicating the dispersion of recording characteristics due to the optimum value of the driving voltage unique to each recording head and the manufacturing variation of the recording head is automatically read from the recording head for each recording head. Ink jet recording apparatuses (see Patent Documents 1 and 2) that perform individual control have been proposed.

  These ink jet recording apparatuses are methods and apparatuses for eliminating the positional deviation of the recording position in the initial state such as when the recording head is replaced. However, the positional deviation of the recording position is caused by moisture from the ink ejected from the recording head. The position of the recording position cannot be dealt with, for example, when the properties of the ink change with time due to evaporation of the ink or when the driving waveform of the driving voltage applied to the recording head changes with time.

As an ink jet recording apparatus capable of coping with the positional deviation of the recording position due to such a change over time, a test pattern is created by ejecting ink from the recording head, and the landed ink is detected by a sensor or the like and the original recording position is detected. A recording apparatus (for example, refer to Patent Documents 3 to 5) that determines the deviation from the recording head, the ejection speed of ink ejected from the recording head, the moving speed of the carriage, the relationship between the recording head and the recording medium An inkjet recording apparatus that detects a distance and refers to a correction table having a misregistration correction value stored in a storage device to determine a corresponding correction value to eliminate misregistration of the recording position (see Patent Document 6). Are known.
JP-A-9-234883 JP-A-8-309981 Japanese Patent Publication No. 6-4331 JP-A-4-28548 JP 10-217479 A JP-A-6-143724

  Certainly, according to the ink jet recording apparatuses described in Patent Documents 3 to 5, the positional deviation of the recording position due to the change in the properties of the ink over time can be eliminated by checking it appropriately. However, the misregistration of the ink recording position occurs, for example, when the moving speed of the carriage on which the recording head is mounted is changed, in addition to the change over time such as the mounting error of the recording head and the properties of the ink. .

  That is, when the ink ejection timing from the recording head is not appropriately corrected when changing the carriage speed, the ink recording position on the recording medium is shifted as shown in FIGS. It will occur.

  In the ink jet recording apparatuses described in Patent Documents 3 to 5, when the carriage speed is changed, it is necessary to correct the misregistration of the recording position, and the correction work becomes complicated and after the carriage speed is changed. The next recording operation cannot be started immediately, and the efficiency of the recording operation is reduced.

  On the other hand, in the ink jet recording apparatus described in Patent Document 6, a specific ink jet recording apparatus with a carriage speed of about 1 m per second is assumed, and no significant change in the carriage speed is assumed.

  In addition, since the document does not originally describe how to determine the misregistration correction value, it is not possible to obtain knowledge about how to create a correction table. Even if it is configured to select a misregistration correction value corresponding to the carriage speed from the storage device in accordance with a significant change in the carriage speed, the ink ejection speed, the carriage movement speed, the recording head-the recording medium It is very difficult to prepare a correction table by determining all accurate misregistration correction values in advance for all numerical ranges having a very wide range of distances.

  With respect to this point, according to this document, since the ink ejection speed of about 7 to 30 m per second can be treated as being sufficiently large with respect to the carriage speed of about 1 m per second, correction regarding fluctuations in the ink ejection speed can be omitted. However, in the ink jet recording apparatus in which the carriage speed can be changed greatly as described above, such an assumption is not established and the above problem cannot be solved.

  Therefore, the present invention can eliminate the positional deviation of the recording position of the ink on the recording medium caused by a change in the recording head with respect to the carriage, an ink property, etc. over time, or a change in the carriage speed. Moreover, an object of the present invention is to provide an ink jet recording apparatus that can easily and accurately eliminate misalignment.

In order to solve the above-mentioned problem, the invention according to claim 1
In an ink jet recording apparatus that performs recording by relatively moving a recording head and a recording medium using a serial recording head provided with an ink discharge port for discharging ink,
A head position detecting device capable of detecting the position of the recording head with respect to the recording medium;
A control device that applies a driving voltage to the recording head at the ejection position based on the set recording conditions and the position information from the head position detection device and ejects the ink from the ink ejection port;
A recording position detecting device capable of detecting the recording position of the ink landed on the recording medium;
When the ink is ejected from the recording head under different conditions, the ejection speed of the ejected ink is calculated based on the interval between the recording positions of the ink detected by the recording position detection device, and based on the calculated ejection speed of the ink And a correction device that corrects the recording condition set in the control device.

  According to the first aspect of the present invention, the ink jet recording apparatus correcting device confirms the position of the recording head based on the detection result from the head position detecting device, and, for example, the reciprocating recording head traveling through the control device. The recording position detection device detects ink that has landed at different recording positions on the recording medium by ejecting ink at the same ejection position from the recording head that moves at different movement speeds in the same direction during operation and backward operation. The correction device measures the interval between the recording positions of the ink, calculates the ink ejection speed based on the motion model, and sets the drive voltage set in the control device based on the calculated ink ejection speed. And correction of recording conditions such as head temperature and ink ejection timing.

  According to a second aspect of the present invention, in the ink jet recording apparatus according to the first aspect, the correction device is configured to perform a forward operation at the same ejection position from the recording head that reciprocates in the main scanning direction with respect to the recording medium. The present invention is characterized in that the ejection speed of the ejected ink is calculated based on the interval between the recording positions of the ink detected by the recording position detecting device when each of the inks is ejected during the backward operation.

  According to the second aspect of the present invention, the correction device causes the ink to be ejected at the same ejection position during the forward operation and the backward operation of the recording head that reciprocates via the control device, and different recording positions on the recording medium. The recording position detection device detects the ink landed on the ink and transmits it to the correction device. The correction device measures the interval between the ink recording positions and calculates the ink ejection speed based on the motion model. Based on the ejection speed, the recording conditions such as drive voltage, head temperature, and ink ejection timing set in the control device are corrected.

  According to a third aspect of the present invention, in the ink jet recording apparatus according to the first aspect, the correcting device discharges the same from the recording head that moves at different moving speeds in the same direction in the main scanning direction with respect to the recording medium. When the ink is ejected at each position, the ejection speed of the ejected ink is calculated based on the interval between the ink recording positions detected by the recording position detecting device.

  According to the invention described in claim 3, the correction device causes the ink to be ejected at the same ejection position from the recording heads that move at different movement speeds in the same direction via the control device, and different recording positions on the recording medium. The recording position detection device detects the ink landed on the ink and transmits it to the correction device. The correction device measures the interval between the ink recording positions and calculates the ink ejection speed based on the motion model. Based on the ejection speed, the recording conditions such as drive voltage, head temperature, and ink ejection timing set in the control device are corrected.

  According to a fourth aspect of the present invention, in the ink jet recording apparatus according to any one of the first to third aspects, the correction device calculates an ink ejection speed based on an interval between ink recording positions. In this case, the calculation is performed according to an expression including an exponential function as a term of air resistance.

  According to a fourth aspect of the present invention, the correction device is a force equation applied to the ink as an equation of motion used when calculating the ink ejection speed based on the interval between the ink recording positions in the correction of the recording condition. Using an equation of motion that takes into account a resistance force proportional to the velocity, the ink ejection velocity is calculated according to an equation including an exponential function as a term of air resistance calculated from the equation of motion.

  According to a fifth aspect of the present invention, in the ink jet recording apparatus according to any one of the first to fourth aspects, the correction device moves when the moving speed of the recording head is changed to a different moving speed. The ink ejection timing after the change of the moving speed is corrected based on the ink ejection speed calculated under the recording conditions before the speed change.

  According to the fifth aspect of the present invention, when there is an instruction to change the moving speed of the recording head, the correcting device changes the moving speed based on the ink ejection speed calculated under the recording conditions before changing the moving speed. The ink ejection timing is automatically calculated to correct the ejection timing as the recording condition.

The invention according to claim 6 is the ink jet recording apparatus according to any one of claims 1 to 5,
When a plurality of the recording heads are provided,
The correction device calculates an ink ejection speed for each of the plurality of recording heads so that the recording positions of the ink on the recording medium are the same in the main scanning direction based on the calculated ejection speeds of the ink. Further, the present invention is characterized in that the ejection timing is corrected for each recording head.

  According to the invention described in claim 6, the correction device eliminates the positional deviation of the recording position for each of the plurality of recording heads, and then inks from the recording heads to the same recording position on the recording medium. When the ink is ejected, the ejection timing of each recording head, which is a recording condition, is corrected so that the ink lands on the same recording position.

The invention according to claim 7 is the ink jet recording apparatus according to any one of claims 1 to 6,
The recording head is configured to be able to change the ejection speed of the ejected ink according to the change of the applied drive voltage,
The correction device is configured such that the control device corrects a drive voltage to be applied to the recording head based on the calculated ink ejection speed.

  According to the seventh aspect of the present invention, the correction device calculates the correction value of the drive voltage to be applied to the recording head from the ink ejection speed calculated based on the interval between the ink recording positions, and is the recording condition. Correct the drive voltage.

  According to an eighth aspect of the present invention, in the ink jet recording apparatus according to the seventh aspect, the correction device corrects the drive voltage to be applied to the recording head by the control device based on the calculated ink ejection speed. When performing, a correction value of the drive voltage is calculated using a linear function as a relational expression between the injection speed and the drive voltage.

  According to the eighth aspect of the present invention, the correction device obtains the correction value of the drive voltage to be applied to the print head from the ink injection speed calculated based on the interval between the ink recording positions, the injection speed and the drive voltage. The drive voltage, which is a recording condition, is corrected by calculation using a linear function as a relational expression.

The invention according to claim 9 is the inkjet recording apparatus according to any one of claims 1 to 8,
The recording head is configured to be able to change the ejection speed of the ejected ink according to the change in the temperature of the ink inside,
The correction device is configured to correct the temperature of the ink in the recording head to be maintained by the control device based on the calculated ink ejection speed.

  According to the ninth aspect of the invention, the correction device calculates the amount of change in the temperature of the ink inside the recording head to be changed from the ink ejection speed calculated based on the interval between the ink recording positions, and the recording condition The ink temperature in the recording head is corrected.

The invention according to claim 10 is the ink jet recording apparatus according to any one of claims 1 to 9,
A transport device that transports the recording medium in the sub-scanning direction during recording,
The correction device is configured to detect an interval between ink recording positions by causing ink to land on a stationary recording medium without driving the transport device when calculating the ink ejection speed. It is characterized by being.

  According to the tenth aspect of the present invention, the correction device detects the interval between the ink recording positions by causing the ink to land on the stationary recording medium without driving the recording medium conveying device.

  According to an eleventh aspect of the present invention, in the ink jet recording apparatus according to any one of the first to tenth aspects, a photocurable ink is used as the ink.

  According to the invention described in claim 11, a photocurable ink that is cured by light irradiation is used as the ink.

  According to the first aspect of the present invention, prior to the normal recording process of the ink jet recording apparatus, the ink properties and the like over time with reference to the standard value of the ink ejection speed based on the recording conditions set in the control apparatus. In the correction of the recording conditions to eliminate the misregistration caused by the change in the recording and the correction of the ejection timing between the multiple recording heads, the recording conditions should be corrected so that the ink ejection speed matches the standard value. Thus, it is possible to accurately align the ink ejection positions.

  In addition, it is possible to clearly grasp the amount of change in drive voltage and head temperature for the print head that should be corrected to return the ink ejection speed to the standard value according to the difference between the standard value of the ink ejection speed and the calculated current value. For this reason, it is possible to easily and accurately correct the recording conditions such as the driving voltage and the head temperature and to eliminate the positional deviation of the recording position accurately.

  As described above, according to the present invention, the positional deviation of the recording position on the recording medium can be easily and accurately eliminated by correcting the recording condition by a unified method of adjusting the ink ejection speed to the standard value. It becomes possible.

  According to the second aspect of the present invention, the ink is ejected from the recording head at the same ejection position during the forward operation and the backward operation, and the ink is landed at different recording positions on the recording medium. Since it is possible to determine the interval as a recording position that is clearly separated rather than determining the interval between the recording positions of the semi-overlapping inks that are slightly misaligned due to the same manner as in actual recording. It is possible to accurately determine whether or not a deviation has occurred, and it is possible to easily and accurately calculate how much the recording condition should be corrected.

  Further, when the interval between different recording positions is L, for example, at the time of normal recording, the recording head is separated by L / 2 on the upstream side in the forward operation direction and the backward operation direction of the recording position on the recording medium to be recorded. If the ejection timing is adjusted or corrected so that ink is ejected at the ejected position, it is possible to easily and accurately eliminate the displacement of the recording position at all the recording positions on the recording medium. The effects of the described invention can be exhibited accurately.

  According to the invention described in claim 3, by ejecting ink at the same ejection position from the recording heads moving at different movement speeds in the same direction and landing the ink at different recording positions on the recording medium, The interval can be determined as a clearly separated recording position, rather than the interval between the recording positions of the semi-overlapping inks that are slightly misaligned by the same way of hitting as in the conventional recording. Therefore, it is possible to accurately determine whether or not a positional deviation has occurred, and it is possible to easily and accurately calculate how much the recording condition should be corrected.

  In addition, if the ejection timing is adjusted or corrected based on the calculated interval between the recording positions and the motion model, the positional deviation of the recording positions between the plurality of recording heads can be easily and accurately performed at all the recording positions on the recording medium. Therefore, the effect of the invention described in claim 1 can be exhibited accurately.

  According to the fourth aspect of the present invention, the ink ejection speed is easily and accurately calculated by calculating the ink ejection speed according to an expression including an exponential function as an air resistance term in the correction of the recording condition. Therefore, the effects of the inventions described in the above claims can be more accurately exhibited.

  According to the fifth aspect of the present invention, as described above, since the recording conditions are corrected so that the ejection speed of the ink ejected from the recording head always becomes the standard value, the movement is performed using the standard value. The correction value of the ink ejection timing from the recording head after the speed change can be automatically and accurately calculated, and the correction value can be easily calculated without calculating the ink ejection speed again. The effects of the inventions described in the above claims can be exhibited accurately.

  According to the sixth aspect of the present invention, it is possible to eliminate the positional deviation of the recording position for each recording head and to correct the ejection timing of each recording head for each of the recording heads. It is possible to easily and accurately eliminate the displacement of the recording position between the plurality of recording heads at the position, and the effects of the invention described in the above claims can be exhibited accurately.

  According to the seventh aspect of the present invention, the drive voltage which is a recording condition can be corrected to return the ink ejection speed to its standard value so that the ink ejection speed can be maintained constant. It becomes possible to exhibit the effect of invention described in (2) more effectively.

  According to the eighth aspect of the invention, since the drive voltage is corrected using a linear function as a relational expression between the ink ejection speed and the drive voltage applied to the recording head, the correction value of the drive voltage can be calculated. It becomes very easy and the effects of the invention described in the above claims can be more effectively exhibited.

  According to the ninth aspect of the invention, the temperature of the ink in the recording head, which is the recording condition, can be corrected to return the ink ejection speed to its standard value, and the ink ejection speed can be kept constant. The effects of the invention described in the above claims can be more effectively exhibited.

  According to the tenth aspect of the present invention, when the recording medium is transported, there is a possibility that a blur occurs in the direction orthogonal to the transport direction and the interval between the recording positions cannot be accurately detected. By performing the correction process in a stationary state without the occurrence of this, it is possible to prevent such blurring and to accurately measure the interval between recording positions. Therefore, the effects of the invention described in the above claims can be more accurately exhibited.

  According to the invention described in claim 11, the invention described in each of the claims is applied to the ink jet recording apparatus using the photocurable ink, and the photocurable type having different image quality depending on the scanning speed and the ink curing timing. Even in an ink jet recording apparatus, its usefulness can be effectively exhibited.

  Embodiments of an ink jet recording apparatus according to the present invention will be described below with reference to the drawings.

[First Embodiment]
In the present embodiment, a case where so-called bidirectional recording is performed in a serial head type inkjet recording apparatus will be described.

  FIG. 1 is a diagram illustrating a configuration of a recording unit of the inkjet recording apparatus according to the present embodiment, and FIG. 2 is a block diagram illustrating a control configuration in the inkjet recording apparatus of FIG.

  A flat platen 2 that supports the recording medium S from the back side of the recording surface is disposed substantially horizontally in the recording unit of the inkjet recording apparatus 1, and upstream of the platen 2 in the sub-scanning direction indicated by an arrow Y in the drawing. Conveying rollers 3 for conveying the recording medium S in the sub-scanning direction Y are disposed on the side and the downstream side, respectively.

  A rotational driving force of a drive motor (not shown) is transmitted to at least one of the transport rollers 3 via a chain or the like. In the present embodiment, the transport roller 3 and the drive motor constitute a transport device 23 for transporting the recording medium S in the sub-scanning direction Y. Note that, for example, an endless conveyance belt may be stretched between the conveyance rollers, and the recording medium S may be conveyed while being placed on the conveyance belt.

  Above the platen 2, a rod-shaped guide rail 4 extends in the main scanning direction indicated by an arrow X in the drawing, which is parallel to the platen 2 and orthogonal to the sub-scanning direction Y. A carriage 5 is supported. The carriage 5 is regulated by the guide rail 4 so that the distance between the bottom surface of the carriage 5 and the platen 2 is maintained constant. The carriage 5 is guided by the guide rail 4 and can be reciprocated in the main scanning direction X.

  In the vicinity of the guide rails on both sides of the platen 2 in the main scanning direction, a pair of pulleys 6 a and 6 b that are rotatable around a rotation axis along the vertical direction are arranged. A belt 7 is stretched between the pair of pulleys 6 a and 6 b so that a span is parallel to the guide rail 4, and both ends of the belt 7 are fixed to the carriage 5.

  Further, the output shaft of the motor 8 is directly connected to the rotation shaft of one pulley 6a, and the rotation drive of the motor 8 is transmitted to the belt 7 through the pulley 6a, so that the belt 7 circulates between the pulleys 6a and 6b. The carriage 5 reciprocates along the guide rail 4 as the belt 7 circulates. In this embodiment, the pulleys 6a and 6b, the belt 7 and the motor 8 constitute a carriage driving device 22 for reciprocating the carriage 5 in the main scanning direction X.

  Below the guide rail 4, a linear scale 9 for specifying the position of the carriage 5 is provided along the guide rail 4. A sensor 10 for reading a mark provided on the linear scale 9 is attached to the back of the side surface of the carriage 5, and the sensor 10 reads the mark on the linear scale 9 and transmits a pulse signal. .

  The linear encoder 24 including the linear scale 9 and the sensor 10 can detect the position of the recording head 11 mounted on the carriage 5 with respect to the recording medium S by specifying the position of the carriage 5 in this way. In this embodiment, the head position detection device is configured.

  Mounted on the bottom surface of the carriage 5 is a recording head 11 in which a plurality of nozzles (not shown) that eject ink to the recording medium S supported by the platen 2 are provided in a row. A plurality of recording heads 11 are arranged so as to correspond to inks of each color such as yellow (Y), magenta (M), cyan (C), and black (K), for example.

  Although not shown, the carriage 5 is also equipped with a plurality of sub ink tanks for storing the inks of the respective colors to be supplied to the recording head 11, and the sub ink tanks store the inks of the respective colors. The ink tanks to be stored are connected via supply pipes.

  The recording head 11 is deformed by an electrostrictive effect when a driving voltage is applied to a piezoelectric element (not shown) provided inside the recording head from a power supply device (not shown) based on a control signal of the control device 20. The ink in the ink chamber in the recording head is pressurized by the deformation, and the ink is ejected from the ink ejection port of the nozzle provided on the lower surface of the recording head 11, that is, the ejection surface facing the recording surface of the recording medium S. Has been.

  The piezoelectric element used in the present embodiment is capable of adjusting the degree of deformation due to the electrostrictive effect in accordance with the driving voltage applied from the power supply apparatus, and is applied to the piezoelectric element inside the recording head from the power supply apparatus. By changing the voltage, the ejection speed of the ink ejected from the ink ejection port of the recording head 11 can be varied. The relationship between the drive voltage to be applied and the standard value of the ink ejection speed differs depending on the type of ink. In this embodiment, the standard of the drive voltage and the ink ejection speed for all the inks used as shown in FIG. An expression or table representing the relationship with the value is stored in the control device 20.

  Instead of using a piezoelectric element, it is also possible to use, for example, a heating element, and even a recording head of a type that discharges ink from an ink discharge port by bubbles generated in ink by heating of the heating element by application of a driving voltage. As in the case of a recording head using a piezoelectric element, the ink ejection speed can be changed by changing the drive voltage.

  In this embodiment, although not shown in the drawing head 11 and the sub ink tank, a heater for heating and maintaining ink and a temperature sensor for temperature management are provided. By changing the temperature of the ink in the recording head, the ejection speed of ink ejected from the ink ejection port can be changed.

  Here, the ink used in the present embodiment is a photocurable ink that is cured and fixed on a recording medium when irradiated with light, and an ultraviolet curable ink that is cured by irradiation with ultraviolet light is preferably used. The ink is not limited to ultraviolet curable ink or light curable ink.

  As the ultraviolet curable ink, a radical polymerization ink containing a radical polymerizable compound, a cationic polymerization ink containing a cationic polymerizable compound, and a radical polymerization ink and a cationic polymerization ink were combined as a polymerizable compound. Hybrid ink is applicable. In particular, it is preferable to use a cationic polymerization ink that has almost no inhibitory action on the polymerization reaction due to oxygen and is excellent in functionality and versatility. The ink includes a polymerizable compound that is polymerized and cured with light other than ultraviolet light, and a photoinitiator that initiates a polymerization reaction between the polymerizable compounds with light other than ultraviolet light, such as electron beams, X-rays, and infrared light. May be applied.

  Light irradiation devices 12 that irradiate light onto the ink landed on the recording medium S are provided on both sides of the recording head 11 in the main scanning direction on the bottom surface of the carriage. In the present embodiment, since ultraviolet curable ink is used as the photocurable ink, an ultraviolet light source is employed as the light source of the light irradiation device 12, and a high pressure mercury lamp, a metal halide lamp, a black light, a hot cathode tube, A cold cathode tube, LED (Light Emitting Diode), etc. are employable. Further, if the ink is cured by light other than ultraviolet rays, a light source suitable for the curing is used.

  A CCD (Charge Coupled Device) camera 13 is attached to the side surface of the carriage 5 as a recording position detection device capable of detecting the recording position of the ink landed on the recording surface of the recording medium S. In this embodiment, the CCD camera Reference numeral 13 is attached to the side surface of the carriage 5 on the side where the recording positions of the two inks recorded during the forward operation and the backward operation of the carriage 5 can be detected at the same time during the backward operation.

  The CCD camera 13 only needs to be able to detect the ink recording position on the recording medium, and is not necessarily attached to the carriage 5. In addition to the CCD camera, for example, the recording position detection device can detect the presence or absence of ink on the recording surface of the recording medium S as long as it can detect the recording position of the ink that has landed on the recording medium. It is also possible to use a simple sensor or the like.

  The control device 20 is constituted by a computer in which a CPU, ROM, RAM, input / output interface and the like (not shown) are connected to a bus. The control device 20 is connected to an input device 21 such as a keyboard, a mouse, various disk drives, and an external computer capable of communication.

  The control device 20 is connected via an input device 21 to the distance between the recording head and the platen, the thickness of the recording medium S, the type of ink used for each recording head 11, the drive voltage applied to each recording head 11, Head temperature indicating the temperature of ink in the recording head, carriage speed indicating the moving speed of the recording head 11 in the main scanning direction, recording method for specifying bi-directional recording or unidirectional recording, and how many passes the image for the head width is recorded Recording conditions such as the number of passes for specifying whether to perform the recording are input and set. In addition, data of an image to be recorded on the recording medium S is input to the control device 20 via the input device 21.

  The control device 20 is connected to the carriage drive device 22 composed of the pulleys 6a and 6b, the belt 7 and the motor 8 described above, and the transport device 23 composed of the transport roller 3 and the drive motor. Based on the set recording conditions, the control device 20 issues a control signal to the carriage drive device 22 to reciprocate the carriage 5 in the main scanning direction X at the set carriage speed, and issues a control signal to the transport device 23. Thus, the recording medium S is intermittently conveyed in the sub-scanning direction Y at a conveyance width and a conveyance speed based on the set number of passes.

  The control device 20 is connected to a heater or a temperature sensor provided in the above-described recording head 11 or the like, and the control device 20 displays the measurement result transmitted from the temperature sensor based on the set recording conditions. While monitoring, the heater is heated to maintain the temperature of the ink such as the recording head at a set head temperature.

  The control device 20 is connected to the sensor 10 of the linear encoder 24 as the head position detection device described above, and the control device 20 counts the pulse signal input from the sensor 10 and mounts it on the carriage 5 or the carriage 5. The position and moving speed of the recording head 11 in the main scanning direction are recognized.

Further, the control device 20 confirms the position of each recording head 11 based on the position information from the sensor 10 of the linear encoder 24, while the recording head 11 should eject ink based on the input image data. It is determined whether or not it is at the ejection position, and if it is determined that it is at the ejection position, a control signal is transmitted to the power supply device to the piezoelectric element corresponding to the nozzle ejection port that should eject the ink of the recording head 11. A pulse voltage corresponding to the set drive voltage V _S as shown in FIG. 4 is applied to cause the recording head 11 to eject ink from the ink ejection port.

  Although not shown in FIG. 2, the control device 20 may, for example, turn on and off the light irradiation device 12, supply ink from the sub ink tank to the recording head 11, maintain the recording head 11, and the like. The inkjet recording apparatus 1 is configured to perform general control.

  On the other hand, a correction device 25 for correcting the set recording condition is connected to the control device 20, and the correction device 25 is connected to the linear encoder 24 which is a head position detection device and the above-described recording medium. Detection results are input from the CCD camera 13 which is a recording position detecting device capable of detecting the recording position of the landed ink. For example, the correction device 25 may be configured by a computer or the like separate from the control device 20, or may be configured as one module configuring the control device 20.

  The correction device 25 is a recording set in the control device 20 prior to the start of the next image recording, such as when the inkjet recording device 1 is installed, when the recording head 11 or ink is replaced, during maintenance, or when the carriage speed is changed. It is configured to correct and reset the conditions, and to automatically eliminate the displacement of the recording position of the ink that lands on the recording medium during normal recording.

That is, at the time of normal recording, as shown in FIG. 5, the control device 20 performs ink at different ejection positions q _a and q _b during the forward operation and the backward operation in the reciprocating movement of the recording head 11 in the main scanning direction X, respectively. The ink is discharged and ink is landed on the same recording position Q on the recording surface of the recording medium S. The correction device 25 eliminates a slight misalignment between the recording position during the forward operation and the recording position during the backward operation, which should be the same position Q during the normal recording.

  Here, an ink motion model used for calculation of a correction value in the correction device 25 will be described. As shown in FIG. 6, in the system in which the inkjet recording apparatus 1 is stationary, when the x axis is taken in the main scanning direction and the y axis is taken in the direction from the recording head 11 to the recording medium S, this model The ink motion is calculated based on the following formulas (3) to (6) obtained by solving the motion equations of the following formulas (1) and (2) that are set in consideration of the air resistance.

In the equation, a _x, a _y, v _x, v _y each represent a x and y components of the acceleration a and velocity v of the ink, v ₀ is the initial velocity, theta ₀ is the initial velocity vector of the ink in the ink And the x axis, m is the mass of the ink, g is the gravitational acceleration, and c is a proportional constant of air resistance that increases in proportion to the velocity. The ink mass m and proportionality constant c are experimentally determined in advance.

The x component v ₀ cosθ ₀ of the initial ink velocity v ₀ is equal to the moving velocity v _H of the recording head 11, and the carriage velocity v _H input from the input device 21 is substituted for v ₀ cosθ ₀ in the relational expression. . The y component v ₀ sinθ ₀ of the initial ink velocity v ₀ represents the ink ejection speed in the direction of the recording medium at the ink ejection port 26 of the recording head 11 in the recording head stationary system.

In the present embodiment, the correction device 25 uses the ink ejection speed v ₀ sinθ ₀ at the ink ejection port as a reference for the ink flying speed, and calculates the ink ejection speed v ₀ sinθ ₀ . Therefore, the following calculation operation is performed according to the calculation flow shown in FIG.

First, the correction device 25 moves the carriage 5 back and forth in the main scanning direction X via the control device 20 in a state where the recording medium S is stationary on the platen without driving the transport device 23, and the sensor of the linear encoder 24. As shown in FIG. 8, while recognizing the position of the recording head 11 based on the position information transmitted from the recording head 10, ink is ejected from the recording head 11 at the same ejection position q during forward operation and backward operation. Ink is landed on the recording positions Q _a and Q _b on the recording surface of the medium S (step S10).

Then, the recording position Q _a of the CCD camera 13 has detected moving together with the recording head 11, Q _b recording position Q _a based on the position information, to measure the distance L Q _b (step S11). Then, L / 2 the as the distance of the recording position Q _a discharge position q and the ink of the recording head 11 (5) substituted into equation x, further the equation of v ₀ cos [theta] ₀ on the set the carriage velocity v _H Is substituted to calculate the flight time t _q-Qa from the time the ink is ejected until it lands (step S12).

Further, the correction device 25 reads the recording head-platen distance l _HP and the thickness l _S of the recording medium S from the recording conditions set in the control device 20, and records the recording head 11 and the recording medium S as the difference between them. The distance l _HS between them is obtained and substituted for y in the above equation (6), and the flying time t _q-Qa calculated in the equation is substituted for calculating the ink ejection speed v ₀ sinθ ₀ (step S13). .

The correction device 25 discharges ink from the recording head 11 at the same ejection position q during the forward operation and the backward operation at the same ejection position q, and records the recording positions Q _a and Q _b of the ink recorded on the recording medium S. and it calculates the injection speed v ₀ sin [theta ₀ of the ink on the basis of the distance L.

FIG. 9 is a graph showing an example of the relationship between the ink ejection speed v ₀ sinθ ₀ calculated in this way and the interval L between the recording positions Q _a and Q _b . From this graph, it can be seen that at the same carriage speed v _H , the interval L between the recording positions Q _a and Q _b decreases as the ink ejection speed v ₀ sinθ ₀ increases. This is because the ink ejection speed v ₀ sin θ ₀ itself does not depend on the carriage speed, but the ink arrival time from the recording head 11 to the recording medium S decreases as the ink ejection speed v ₀ sin θ ₀ increases. This is because the moving distance of the ink in the x-axis direction is shortened.

In addition, it can be seen from this graph that at the same ink ejection speed, the interval L between the recording positions Q _a and Q _b increases as the carriage speed v _H increases. This is the expression (3) or (5). This is because the movement distance x and the velocity v _x of the ink in the x-axis direction depend on v ₀ cos θ _0, that is, the carriage velocity v _{H as shown} in FIG.

The reason why the recording medium S is stopped in the above operation is that the recording medium S is transported in the sub-scanning direction while the reciprocating movement of the recording head 11 is changed from the forward operation to the backward operation. This is to avoid the occurrence of blurring and the inability to accurately detect the interval L between the recording positions Q _a and Q _b .

On the other hand, the ink ejection speed v ₀ sinθ ₀ can be changed by changing the drive voltage applied to the recording head 11 as described above. The correlation between the change in the drive voltage from the set drive voltage and the ink ejection speed v ₀ sinθ ₀ that changes with the change is obtained by experiments. Figure 10 is a graph showing an example of a correlation between the injection rate of change in the ink of the driving voltage, within the practical range of the driving voltage as shown in FIG. 10, normally, the variation of the driving voltage V _S The graph showing the correlation between the minute ΔV _S and the ink ejection speed v ₀ sinθ ₀ is substantially linear for each ink type.

For this reason, in the present embodiment, the correction device 25 is provided with a linear function as a relational expression representing the correlation between the change ΔV _S of the drive voltage and the ink ejection speed v ₀ sinθ ₀ for each ink type. In addition, information on the slope a and intercept b of the linear function, which is a relational expression, is stored in a storage device (not shown) of the correction device 25 for each ink type.

Further, as described above, the ink ejection speed v ₀ sinθ ₀ can also be changed by changing the ink temperature of the recording head 11, and within the practical temperature range as shown in FIG. It has been found that there is a proportional relationship between the ink temperature rise and the change in the ink ejection speed v ₀ sinθ ₀ that changes accordingly.

Therefore, in the present embodiment, the storage device of the correction device 25 stores a proportional constant k that represents the rate of change in the temperature of the ink with respect to the unit change amount of the ink ejection speed v ₀ sinθ ₀ for each ink type. .

  Next, adjustment of the positional deviation of the recording position and correction of the recording condition in the inkjet recording apparatus 1 according to the present embodiment will be described.

In the present embodiment, adjustment of misregistration and correction of recording conditions are performed on the basis that the ink ejection speed v ₀ sinθ ₀ based on the recording conditions set in the control device 20 is always kept constant. If a new recording condition is set for the control device 20, the ink ejection speed v ₀ sinθ ₀ to be maintained is also changed accordingly.

[Adjusting the recording position offset]
Adjustment of the recording position misalignment is performed when the ink jet recording apparatus 1 is initially installed, when the recording head 11 is replaced, when ink is replaced, or when the recording condition is reset and a new recording condition is set in the control device 20. To be done. As described above, when the recording condition is input to the control device 20 and the driving voltage V _S is set, even if the recording operation is performed as it is in an ideal state, the recording position is not displaced, and it is necessary to adjust the displacement. In reality, however, the drive waveform shown in FIG. 4 deviates from the ideal shape due to manufacturing variations of the circuit board, and if the recording operation is performed as it is, the recording position is displaced, so recording is performed for each recording head. It is necessary to adjust the positional deviation.

FIG. 12 is a flowchart showing a procedure for adjusting the recording position misalignment. When receiving the misalignment adjustment instruction, the correction device 25 first reads out the recording conditions set in the control device 20, stores them in the storage device, temporarily sets the drive voltage V _S, and the relationship shown in FIG. Based on this, the standard value of the ink ejection speed v ₀ sinθ ₀ is determined (step S20) and stored in the storage device.

Then, the ejection position q of the recording head 11 for performing the arithmetic operation shown in FIG. 7 is provisionally determined (step S21), and the current ink ejection speed v ₀ sin θ ₀ is calculated by the arithmetic operation (step S22). Specifically, as shown in FIG. 8, ink is ejected from the recording head 11 at the same ejection position q to the stationary recording medium S as shown in FIG. Based on the interval L between the ink recording positions Q _a and Q _b , the current value of the ink ejection speed v ₀ sinθ ₀ is calculated.

Subsequently, the correction device 25 is shown in FIG. 10 according to the type of ink used from the storage device to the recording head 11 in order to correct the current value of the ink ejection speed v ₀ sinθ _{0 to} the standard value. The slope a of the linear function representing the correlation between the change ΔV _S of the drive voltage and the ink ejection speed v ₀ sinθ ₀ is read, and the change ΔV _s of the drive voltage is calculated based on the following equation (7). Then, the correction value of the drive voltage is determined (step S23).
ΔV _s = (standard value of ink ejection speed v ₀ sin θ ₀₋ current value) / a (7)

Then, the correction device 25 determines a value obtained by adding the correction value ΔV _s to the driving voltage V _s as an initial value V _s0 of the driving voltage to be applied to the recording head 11 (step S24), and an initial value of the driving voltage. V _s0 is stored in the storage device, and the initial value V _s0 is transmitted to the control device 20 to reset the drive voltage. The correction device 25 performs this initial adjustment for each recording head, and corrects the driving voltage to adjust the positional deviation of the recording position.

  When the ejection timing of the recording head 11 is adjusted in this way, the recording head 11 is moved forward and backward at any of the recording positions Q of ink recorded on the recording surface of the recording medium S. Positional alignment can be performed accurately without any positional deviation.

[Correction of recording conditions when changes occur over time]
Next, property change and the ink caused by the evaporation of moisture or the like in the ink, the position of the recording position caused by change over time of the drive waveform of the driving voltage V _S applied to the piezoelectric element of the recording head 11 shown in FIG. 4 The correction of the recording condition for eliminating the deviation will be described. This correction work is performed when the apparatus is started up after the continuous stop time of the recording work has elapsed for a predetermined time or when the operating state of the apparatus has exceeded a predetermined time.

FIG. 13 is a flowchart showing a procedure for correcting a recording condition when a change with time occurs. When the correction device 25 receives the recording condition correction instruction at the time point, it first reads the initial value V _{s0 of the} drive voltage and the standard value of the ink ejection speed v ₀ sin θ ₀ from the storage device (step S30). Then, the ejection position q of the recording head 11 for performing the arithmetic operation shown in FIG. 7 is provisionally determined (step S31), and the current value of the ink ejection speed v ₀ sinθ ₀ is calculated by the arithmetic operation (step S32). .

Subsequently, the correction device 25 is shown in FIG. 10 according to the type of ink used from the storage device to the recording head 11 in order to correct the current value of the ink ejection speed v ₀ sinθ _{0 to} the standard value. The linear function slope a representing the correlation between the change ΔV _S of the drive voltage and the ink ejection speed v ₀ sinθ ₀ is read, and the drive voltage is based on the following equation (8) similar to the equation (7). Change ΔV _s is calculated to calculate a drive voltage correction value ΔV _s (step S33).
ΔV _s = (standard value of ink ejection speed v ₀ sin θ ₀₋ current value) / a (8)

Here, in the correlation between the change ΔV _s of the drive voltage and the ink ejection speed v ₀ sinθ ₀ shown in FIG. 10, a range of voltage fluctuation that can correct the drive voltage is preset according to the type of ink. Yes. Therefore, the correction device 25 determines whether or not the calculated correction value ΔV _s is within the correction range of this drive voltage (step S34). If it is within the correction range (step S34: YES), the correction device 25 A value obtained by adding this ΔV _s to the initial value V _s0 is determined as a correction value V _smod of the drive voltage to be applied to the recording head 11 and stored in the storage device, and the correction value V _smod is transmitted to the control device 20. The drive voltage is reset (step S35). Then, the correction process ends.

If the correction device 25 determines that the correction value ΔV _s exceeds the correction range (step S34: NO), the correction device 25 increases the drive voltage so as to increase or decrease the ink ejection speed v ₀ sinθ ₀ to the limit value. After changing to the limit value of the correction range of the drive voltage, the ink in the print head with respect to the unit change amount of the ink ejection speed v ₀ sinθ ₀ corresponding to the type of ink used from the storage device to the print head 11 is changed. A proportional constant k representing the rate of temperature change is read, and a change ΔT in ink temperature T is calculated based on the following equation (9) (step S36).
ΔT = k × (standard value of ink ejection speed v ₀ sinθ ₀₋ limit value) (9)

Here, also in the correlation between the ink temperature rise and the ejection speed change shown in FIG. 11, a temperature fluctuation range in which the ink temperature can be corrected is set in advance according to the ink type. Therefore, the correction device 25 determines whether or not the calculated change ΔT in ink temperature is within the correction range of this ink temperature (step S37). If it is within the correction range (step S37: YES), the ink temperature A value obtained by adding this change ΔT to T is determined as a correction value T _mod of the ink temperature, stored in the storage device, and transmitted to the control device 20 to reset the ink temperature (step S38). Then, the correction process ends.

It should be noted that there is a case where the temperature dependence of the ink ejection speed v ₀ sinθ ₀ is not necessarily reliable for the correction of the ink temperature compared to the correction of the drive voltage. In such a case, after the ink temperature is corrected (step S38), it is possible to confirm whether or not the ink ejection speed v ₀ sinθ ₀ is corrected to the standard value. Further, when the ink ejection speed v ₀ sinθ ₀ is not sufficiently corrected to the standard value, the above procedure can be repeated.

  When the correction device 25 determines that the change ΔT exceeds the correction range in the determination (step S37) (step S37: NO), the correction device 25 displays a warning or generates a warning sound on a display device (not shown). The operator is informed that the ink should be replaced (step S39), and the correction process is terminated.

If the above-described misregistration of the recording position has been adjusted, the ink ejection state from the recording head 11 is changed to the initial state by correcting the ink ejection speed v ₀ sinθ ₀ to the standard value in this way. Thus, the recording position misalignment during the forward operation and the backward operation of the recording head 11 is eliminated.

[Correction of recording conditions when changing carriage speed]
Next, the correction of the recording condition when the carriage speed v _H, that is, the moving speed v _H of the recording head 11 is changed will be described.

As described above, the movement distance in the x-axis direction, that is, the horizontal direction, of the ink ejected from the recording head 11 varies depending on the moving speed v _H of the recording head 11. Therefore, as shown in FIG. 5, in order to make the recording position during the forward operation and the backward operation of the recording head 11 the same position Q, the ejection positions qa, qb and the recording position Q of the recording head 11 Needs to be corrected so that the distance becomes equal to the movement distance of the ink in the x-axis direction.

Therefore, in the present embodiment, the correction device 25 determines that the distance between the ejection position of the recording head 11 and the recording position of the ink is the x-axis direction of the ink even after the moving speed v _H of the recording head 11 is changed to a different speed. The ink ejection timing after the change is calculated on the basis of the ink ejection speed v ₀ sinθ ₀ calculated under the recording conditions before the change so as to be equal to the movement distance of The discharge timing is automatically corrected.

FIG. 14 is a flowchart illustrating a procedure for correcting the recording condition when the carriage speed is changed. As described above, since the ink ejection speed v ₀ sinθ ₀ itself does not depend on the carriage speed v _H , the ink ejection speed v ₀ sinθ ₀ after changing the carriage speed is the same value as before the change. Accordingly, when receiving the carriage speed change instruction, the correction device 25 first reads the standard value of the ink ejection speed v ₀ sinθ ₀ from the storage device (step S40).

At this stage, if necessary, the calculation operation shown in FIG. 7 is performed again to calculate the ink ejection speed v ₀ sinθ ₀ to correct the recording conditions. That is, the ejection position q of the recording head 11 for performing the arithmetic operation shown in FIG. 7 is provisionally determined, and the current value of the ink ejection speed v ₀ sinθ ₀ is calculated by the arithmetic operation (step S41). The recording condition is corrected in the same manner as the correction of the recording condition when the change with time occurs (step S42). If it is not necessary, steps S41 and S42 are omitted.

Subsequently, the correction device 25 reads the recording head-platen distance l _HP and the thickness l _S of the recording medium S from the recording conditions set in the control device 20 as shown in FIG. Then, the distance l _HS between the recording head 11 and the recording medium S is obtained, and this and the standard value of the ink ejection speed v ₀ sinθ ₀ are substituted into the equation (6) to land after the ink is ejected from the recording head 11. The ink flying time t until the ink is calculated is calculated (step S43).

Incidentally, since the flying time t is the same numerical value as the time of flight t _q-Qa calculated by the arithmetic operation, to keep the time of flight t _q-Qa calculated by the arithmetic operation in the storage device, this modification You may comprise so that it may be read in work and it may be made into the flight time t.

Subsequently, the correction device 25 substitutes the calculated or read ink flying time t into the equation (5), substitutes the changed carriage speed v _H into v ₀ cosθ ₀ in the equation, and sets the ink x The movement distance x in the axial direction is calculated. As in the case of the adjustment of the positional deviation of the recording position described above, when the recording position of the ink to be recorded on the recording surface of the recording medium S is the position Q, the recording is performed as shown in FIG. During the forward operation and the backward operation of the head 11, the ejection positions q _a and q _b that are separated from the recording position Q by the distance x on the upstream side in the forward operation direction and the backward operation direction of the recording head 11 from the recording head 11. The ejection timing of the recording head 11 is corrected so as to eject ink (step S44).

  If the ejection timing of the recording head 11 is corrected in this way, at any recording position Q of any ink on the recording surface of the recording medium S, the recording head 11 is moved forward and backward after the carriage speed is changed. Sometimes there is no misalignment. The correction device 25 stores the corrected ejection timings in the forward operation and the backward operation in the recording device and transmits them to the control device 20 to correct the ejection timing. The ejection timing is corrected for all of the plurality of recording heads 11.

  By the way, if the recording conditions are corrected when the carriage speed is changed, the position of the ejection position q of the reference recording head is changed as shown in FIG. In some cases, the recording heads 111 to 114 may be displaced. In such a case, even if the same recording head has been eliminated from the positional deviation during the forward operation and the backward operation, it is possible to perform recording from the different recording heads to the same recording position on the recording medium. There may be a problem of misalignment between so-called recording heads that are not recorded at the same recording position.

  Therefore, in the present embodiment, the correction device 25 recorrects the ejection timings of the recording heads 111 to 114 when correcting the recording conditions when the carriage speed is changed, and positions between the plurality of recording heads. The deviation is corrected (step S45).

Specifically, the correction device 25 scans the recording heads 111 to 114 at the carriage speed after the change, and discharges ink from the same discharge position during forward operation and reverse operation, as shown in FIG. Ink is landed on the recording positions Q _a1 , Q _b1 ,..., Q _a4 , Q _b4 on the recording medium. Then, the CCD camera 13 attached to the carriage detects the recording positions Q _a1 , Q _b1 ,..., Q _a4 , Q _b4, and the detected recording positions Q _a1 , Q _{b1 ,.} Intermediate positions Q _{1 to} Q ₄ are calculated from Q _b4 and stored.

Then, to calculate the average position Q _ave of respective intermediate positions _Q 1 to Q _4, a difference only discharge position of each recording head for the recording heads 111 to 114 and each intermediate position _Q 1 to Q ₄ and the average position Q _ave In order to shift, the ink ejection timings from the recording heads 111 to 114 already stored in the storage device are recorrected.

  In this way, by re-correcting the ejection timing of each of the recording heads 111 to 114, the recording position between the plurality of recording heads at each of the recording positions Q of a large number of inks recorded on the recording surface of the recording medium S. The positional deviation of is eliminated. The correction device 25 stores the ejection timing of each recording head after re-correction in the recording device, and transmits it to the control device 20 to correct the ejection timing.

In this embodiment, the case where the average position Q _ave is automatically calculated and the ejection timing is corrected to match the average position Q _ave has been described. For example, the recording in the main scanning direction on the recording medium designated by the operator is described. It is also possible to configure to match the position. It is also possible to make the ink ejection speeds v ₀ sin θ ₀ of the recording heads 111 to 114 uniform.

As described above, according to the ink jet recording apparatus 1 according to the present embodiment, as shown in FIG. 8, the recording head 11 reciprocally moves in the main scanning direction X with respect to the recording medium S at the same ejection position q. Based on the interval L between the ink recording positions Q _a and Q _b detected by the recording position detecting device such as the CCD camera 13 by ejecting ink during the forward operation and the backward operation, the relational expressions (3) to (6) ) To calculate the ejection speed v ₀ sinθ ₀ of the ejected ink according to the formula.

In addition, in the correction of the recording condition for eliminating the positional deviation caused by the change with time of the ink property or the correction of the ejection timing between the plurality of recording heads accompanying the change in the speed of the carriage 5, the ink ejection speed v ₀ sinθ. _The recording conditions are such that ₀ coincides with the standard value of the ink ejection speed v ₀ sinθ ₀ calculated in the positional deviation adjustment of the recording position performed at the initial installation of the inkjet recording apparatus 1 or when the recording head 11 is replaced. Corrections are made.

For this reason, first, the configuration is such that the interval L between the recording positions Q _a and Q _b of ink recorded by discharging ink from the recording head 11 at the same ejection position q during the forward operation and the backward operation is obtained. recording position Q _a of the ink in the overlapping mid occurs slightly positional deviation in the same Uchikata that during actual recording _as, than obtaining the distance Q _b, clearly spaced recording position Q _a, Q _b Therefore, it is possible to accurately determine whether or not there is a positional deviation.

Further, paying attention to the injection velocity v ₀ sin [theta ₀ of the ink, the modifications and adjustments by performing the basis of the standard value of the injection velocity v ₀ sin [theta ₀ of the ink, it is possible to accurately align the discharge position of the ink possible and with made, it is modified to the injection speed v ₀ sin [theta ₀ of the ink in accordance with the difference between the current value of the injection velocity v ₀ sin [theta ₀ standard values and the ink injection speed v ₀ sin [theta ₀ of the ink back to the standard value The amount of change in drive voltage and head temperature with respect to the power recording head 11 can be clearly grasped, so that the drive voltage and head temperature can be easily and accurately corrected to eliminate the positional deviation accurately.

Further, the printing condition is modified so that the ejection speed v ₀ sinθ _{0 of the} ink ejected from the recording head 11 is always the standard value, so that the carriage is determined based on the standard value of the ejection speed v ₀ sinθ ₀ of the ink. It becomes possible to easily and accurately calculate the correction value of the ejection timing of the ink from the recording head 11 after the speed change.

In this way, by the unified method of always adjusting the ink ejection speed v ₀ sinθ ₀ to the standard value, the relational expressions shown in the above formulas (3) to (6) and FIG. 10, FIG. 7) The recording position on the recording medium has only a correlation between the ejection speed v ₀ sinθ _{0 of} the ink expressed by the equation (8) and the change in the driving voltage of the recording head 11 or the change in the head temperature. Can be easily and accurately eliminated.

[Second Embodiment]
In the present embodiment, a case of so-called unidirectional recording in which ink is ejected to a recording medium only during a forward operation of a recording head that reciprocates in the main scanning direction in a serial head type ink jet recording apparatus will be described.

  The ink jet recording apparatus 1 according to this embodiment has substantially the same configuration as the ink jet recording apparatus 1 in the first embodiment, but the light irradiation device 12 mounted on the carriage 5 is the same as in the first embodiment. A pair is not provided on each side of the recording head 11, but is configured to be mounted only on the side where the ink that has landed on the recording medium S can be irradiated with light.

Further, the calculation operation for calculating the ink ejection speed v ₀ sinθ ₀ in the correction device 25 is also different from that in the first embodiment. The calculation flow of the calculation operation in this embodiment is the same as the calculation flow of the calculation operation in the first embodiment shown in FIG. 7, and will be described with reference to FIG. 7, but the recording position Q _a on the recording medium will be described. , Q _b is different from the first embodiment in how ink is landed.

That is, in the present embodiment, the correction device 25 moves the carriage 5 in the forward movement direction at different movement speeds V _H1 and V _H2 via the control device 20 as shown in FIG. While the position of the recording head 11 is recognized based on the position information transmitted from the recording head 11, ink is ejected from the recording head 11 to the stationary recording medium S at the same ejection position q, and the recording surface of the recording medium S is recorded. Ink is landed on the different recording positions Q _a and Q _b (step S10).

Then, the recording position Q _a, to measure the distance L Q _b on the basis of the position information of the recording position Q _a, Q _b where CCD camera 13 has detected moving together with the recording head 11 (step S11). At this time, if the distances between the ejection position q and the recording positions Q _a and Q _b are L _q-Qa and L _q-Qb , the interval L between the recording positions Q _a and Q _b is
L = _{Lq-Qb-Lq -Qa} (10)
L _{q -Qa} and L _{q -Qb} are obtained by the following equations (11) and (12) by substituting the carriage speeds V _H1 and V _H2 for v ₀ cosθ ₀ in the equation (5), respectively. It is done.

Then, by substituting L _q-Qa and L _q-Qb represented by the equations (11) and (12) into the equation (10), the following equation (13) is obtained.

By substituting the distance L between the recording positions Q _a and Q _b measured in the equation (13) and substituting the set different moving velocities V _H1 and V _H2 , the ink lands after it is ejected. The flight time t until is calculated (step S12).

Further, the correction device 25 reads the recording head-platen distance l _HP and the thickness l _S of the recording medium S from the recording conditions set in the control device 20, and records the recording head 11 and the recording medium S as the difference between them. The distance l _HS between them is obtained and substituted for y in the above equation (6), and the flying time t calculated in the equation is substituted for the ink ejection speed v ₀ sinθ ₀ (step S13).

The above is the calculation operation in the correction device 25 of the present embodiment, and the recording positions of the ink recorded on the recording medium S by ejecting ink from the recording head 11 at the same ejection position q at different carriage speeds V _H1 and V _H2. The ink ejection speed v ₀ sinθ ₀ is calculated based on the interval L between Q _a and Q _b .

  Next, adjustment of misalignment and correction of recording conditions in the inkjet recording apparatus 1 according to the present embodiment are performed as follows.

In this embodiment as well, adjustment of misalignment and correction of recording conditions are performed based on the fact that the ink ejection speed v ₀ sinθ ₀ based on the recording conditions set in the control device 20 is always kept constant. In addition, the timing at which each adjustment or correction is performed is the same as in the first embodiment.

[Correction of drive voltage in initial state]
In the present embodiment, there is no problem of the displacement of the recording position during the forward operation and the backward operation of the recording head 11 unlike the ink jet recording apparatus 1 of the first embodiment. However, as described above, the circuit board is manufactured. Due to the deviation of the drive waveform shown in FIG. 4 due to variations and the like, the ink ejection speed v ₀ sinθ ₀ may not become the standard value under the recording conditions set in the control device 20.

  Therefore, also in the present embodiment, when the ink jet recording apparatus 1 is initially installed, when the recording head 11 is replaced, when ink is replaced, or when the recording condition is reset and a new recording condition is set by the control device 20. The correction device 25 corrects the drive voltage applied to each recording head 11.

  The adjustment of the driving voltage in the present embodiment is performed in the same manner as the processing procedure in the adjustment of the positional deviation of the recording position performed in the first embodiment shown in FIG. 12, and will be described with reference to FIG.

When the correction device 25 receives the drive voltage correction instruction, the correction device 25 first reads out the recording conditions set in the control device 20 and stores them in the storage device to temporarily set the drive voltage V _S. The relationship shown in FIG. Based on this, the standard value of the ink ejection speed v ₀ sinθ ₀ is determined (step S20) and stored in the storage device. The correction device 25 stores different carriage speeds V _H1 and V _H2 specified in advance by the operator in the storage device.

Then, the ejection position q of the recording head 11 for performing the calculation operation is provisionally determined (step S21), and the current ink ejection speed v ₀ sinθ ₀ is calculated by the calculation operation (step S22). Specifically, as shown in FIG. 17, at the same ejection position q with respect to the recording medium S stationary from the recording head 11 moving in the forward operation direction at different carriage speeds V _H1 and V _H2 specified as shown in FIG. Based on the interval L between the ink recording positions Q _a and Q _b recorded on the recording medium S, the current value of the ink ejection speed v ₀ sin θ ₀ is calculated.

Subsequently, the correction device 25 is shown in FIG. 10 according to the type of ink used from the storage device to the recording head 11 in order to correct the current value of the ink ejection speed v ₀ sinθ _{0 to} the standard value. The linear function slope a representing the correlation between the drive voltage change ΔV _S and the ink ejection speed v ₀ sinθ ₀ is read out, and the drive voltage change ΔV _s is calculated based on the equation (7). Then, the correction value of the drive voltage is determined (step S23).

Then, the correction device 25 determines a value obtained by adding the correction value ΔV _s to the driving voltage V _s as an initial value V _s0 of the driving voltage to be applied to the recording head 11 (step S24), and an initial value of the driving voltage. V _s0 is stored in the storage device, and the initial value V _s0 is transmitted to the control device 20 to reset the drive voltage. The correction device 25 corrects the drive voltage for each recording head.

[Correction of recording conditions when changes occur over time]
Next, the correction of the recording condition when a change with time of ink or the like occurs will be described.

When the ink ejection speed v ₀ sinθ ₀ changes due to a change over time in the ink or the like, there arises a problem of misregistration between a plurality of recording heads. Further, in addition to eliminating such misregistration between a plurality of recording heads, and from the viewpoint of performance of the recording heads themselves, ink property management, and the like, also in this embodiment, the ink ejection speed v ₀ sinθ due to changes over time. _It is necessary to monitor the change of ₀ and correct the recording condition when there is a change.

In the present embodiment, the correction device 25 uses the ink ejection speed v ₀ sinθ ₀ when starting up the device after the continuous stop time of the recording work has elapsed for a predetermined time or when the operation state of the device has exceeded the predetermined time. , And if it has changed from the standard value, the recording condition is corrected so as to return to the standard value. The correction of the recording condition when a change with time in the present embodiment occurs is performed in the same processing procedure as in the first embodiment shown in FIG. 13, and will be described with reference to FIG.

As shown in FIG. 9, if the ink ejection speed v ₀ sinθ ₀ changes, the movement distance of the ink in the x-axis direction also changes. Therefore, the recording position Q _a recorded at different carriage speeds V _H1 and V _H2. , Q _b , it can be determined whether or not the ink ejection speed v ₀ sinθ ₀ has changed.

When the correction device 25 receives the recording condition correction instruction at the time point, it first reads the initial value V _{s0 of the} drive voltage and the standard value of the ink ejection speed v ₀ sin θ ₀ from the storage device (step S30). Then, the ejection position q of the recording head 11 for performing the calculation operation is provisionally determined (step S31), the specified different carriage velocities V _H1 and V _H2 are read out and the calculation operation is performed, and the ink ejection speed v _0. The current value of sin θ ₀ is calculated (step S32).

  Since subsequent procedures such as correction of drive voltage, correction of ink temperature, warning of ink replacement, and the like are exactly the same as those in the first embodiment, description thereof will be omitted.

[Correction of recording conditions when changing carriage speed]
Next, the correction of the recording condition when the carriage speed v _H, that is, the moving speed v _H of the recording head 11 is changed, is automatically performed as in the first embodiment. The correction of the recording condition when the carriage speed is changed in the present embodiment is performed in the same processing procedure as that in the first embodiment shown in FIG. 14, and will be described with reference to FIG.

As described above, since the ink ejection speed v ₀ sinθ ₀ itself does not depend on the carriage speed v _H , the ink ejection speed v ₀ sinθ ₀ after changing the carriage speed is the same value as before the change. Accordingly, when receiving the carriage speed change instruction, the correction device 25 first reads the standard value of the ink ejection speed v ₀ sinθ ₀ from the storage device (step S40).

At this stage, if necessary, the calculation operation shown in FIG. 7 is performed again to calculate the ink ejection speed v ₀ sinθ ₀ to correct the recording conditions. That is, the ejection position q of the recording head 11 for performing the arithmetic operation shown in FIG. 7 is provisionally determined, and different designated carriage speeds V _H1 and V _H2 are read out, and the ink ejection speed v ₀ sinθ _{0 is} obtained by the arithmetic operation. Is calculated (step S41), and the recording condition is corrected in the same manner as the correction of the recording condition at the time of occurrence of a change with time (step S42). If it is not necessary, steps S41 and S42 are omitted.

Subsequently, the correction device 25 reads the recording head-platen distance l _HP and the thickness l _S of the recording medium S from the recording conditions set in the control device 20 as shown in FIG. Then, the distance l _HS between the recording head 11 and the recording medium S is obtained, and this and the standard value of the ink ejection speed v ₀ sinθ ₀ are substituted into the equation (6) to land after the ink is ejected from the recording head 11. The ink flying time t until the ink is calculated is calculated (step S43). Incidentally, since the flying time t is the same numerical value as the time of flight t _q-Qa calculated by the arithmetic operation, to keep the time of flight t _q-Qa calculated by the arithmetic operation in the storage device, this modification You may comprise so that it may be read in work and it may be made into the flight time t.

Subsequently, the correction device 25 substitutes the calculated or read ink flying time t into the equation (5), and substitutes the carriage speed v _H after the change into v ₀ cosθ ₀ of the equation, and then changes the result shown in FIG. A distance X between the indicated ejection position q and the recording position Q is calculated. When the recording position of the ink to be recorded on the recording surface of the recording medium S is the position Q, the recording head 11 is moved relative to the recording position Q in the forward operation of the recording head 11, that is, the recording operation. The ejection timing of each recording head 11 is corrected so that ink is ejected from the recording head 11 at the ejection position q separated by the upstream distance X in the forward movement direction (step S44).

  The correction device 25 stores the corrected ejection timing in the recording device and transmits it to the control device 20 to correct the ejection timing. The ejection timing is corrected for all of the plurality of recording heads 11.

  By the way, when the recording condition is corrected at the time of changing the carriage speed, the position of the discharge position q of the reference recording head is changed as shown in FIG. In some cases, the recording heads 111 to 114 may be displaced. In such a case, even if recording is performed from the different recording heads to the same recording position on the recording medium, there may be a problem of misalignment between the recording heads in which the recording is not performed at the same recording position.

  Therefore, also in the present embodiment, the correction device 25 recorrects the ejection timing of each of the recording heads 111 to 114 when correcting the recording condition when changing the carriage speed, so that the correction is performed between the plurality of recording heads. The misalignment is corrected (step S45).

Specifically, the correction device 25 scans the recording heads 111 to 114 at the carriage speed after the change, and discharges ink from the same discharge position during the forward operation and the backward operation, respectively, as shown in FIG. In this manner, ink is landed on the recording positions Q _a1 , Q _b1 ,..., Q _a4 , Q _b4 on the recording medium. Then, the CCD camera 13 attached to the carriage detects the recording positions Q _a1 , Q _b1 ,..., Q _a4 , Q _b4, and the detected recording positions Q _a1 , Q _{b1 ,.} The ejection positions q ₁ , q ₂ , q ₃ , q ₄ for each recording head are calculated from Q _b4 and stored.

Then, the average discharge position q _ave of each of the discharge positions q _{1 to} q ₄ is calculated, and the discharge of each print head is calculated by the difference between each of the discharge positions q _{1 to} q ₄ and the average discharge position q _ave for each of the print heads 111 to 114. The ink ejection timings from the recording heads 111 to 114 already stored in the storage device are recorrected so as to shift the positions.

  In this way, by re-correcting the ejection timing of each of the recording heads 111 to 114, the recording position between the plurality of recording heads at each of the recording positions Q of a large number of inks recorded on the recording surface of the recording medium S. The positional deviation of is eliminated. The correction device 25 stores the ejection timing of each recording head after re-correction in the recording device, and transmits it to the control device 20 to correct the ejection timing.

In the present embodiment, the case where the average discharge position q _ave is automatically calculated and the discharge timing is corrected to match the average discharge position q _ave has been described. However, for example, in the main scanning direction on the recording medium designated by the operator. It is also possible to configure to match the recording position.

  As described above, the ink jet recording apparatus 1 according to the second embodiment has the same function as the ink jet recording apparatus according to the first embodiment, and exhibits the same effects as those of the first embodiment. can do.

FIG. 2 is a diagram illustrating a configuration of a recording unit of the ink jet recording apparatus according to the first embodiment. It is a block diagram which shows the control structure in the inkjet recording device of FIG. It is a graph showing the relationship between a drive voltage and the standard value of the ejection speed of ink. FIG. 6 is a diagram illustrating a driving waveform of a driving voltage applied to a recording head. FIG. 6 is a diagram illustrating a locus of ink that lands on the same recording position during a forward operation and a backward operation during normal recording. It is a figure explaining the coordinate system etc. of the motion model of the ink used for calculation. It is a flowchart which shows the calculation procedure of calculation operation in 1st Embodiment. It is a figure showing the locus | trajectory of the ink discharged by the same discharge position at the time of a forward operation and a backward operation | movement by the correction process by a correction apparatus. 6 is a graph illustrating the relationship between the ink ejection speed calculated according to the ink motion model and the interval between recording positions. It is a graph which shows an example of the correlation with the variation | change_quantity of a drive voltage, and the ejection speed of an ink. It is a graph which shows an example of the correlation with the temperature rise of an ink, and the change of an ejection speed. 6 is a flowchart illustrating a procedure for adjusting a positional deviation of a recording position. It is a flowchart which shows the procedure which corrects the recording conditions at the time of change with time. 6 is a flowchart illustrating a procedure for correcting a recording condition when changing a carriage speed. FIG. 6 is a diagram for explaining a state in which ejection positions are shifted between recording heads. It is a figure explaining the procedure which calculates | requires an intermediate position and an average position from each recording position. It is a figure showing the locus | trajectory of the ink discharged from the same discharge position by the different moving speed by the correction process by the correction apparatus in 2nd Embodiment. It is a figure explaining the relationship between the carriage speed _VH and the distance X between a discharge position and a recording position. It is a figure explaining the procedure which calculates | requires a discharge position and an average discharge position from each recording position. It is a figure explaining the process in which the position shift of a recording position arises by bidirectional | two-way recording. FIG. 6 is a diagram illustrating a process in which a recording position shift occurs between a plurality of recording heads in one-way recording.

Explanation of symbols

1 inkjet recording apparatus 11 printhead 13 CCD camera 20 controller 23 transfer apparatus 24 linear encoder 25 modified device L recording position interval Q of, Q _a, Q _b recording position q, q _a, q _b discharge position S recording medium V _S injection velocity of the moving velocity v ₀ sin [theta ₀ ink driving voltage v _H printhead

Claims (11)

In an ink jet recording apparatus that performs recording by relatively moving a recording head and a recording medium using a serial recording head provided with an ink discharge port for discharging ink,
A head position detecting device capable of detecting the position of the recording head with respect to the recording medium;
A control device that applies a driving voltage to the recording head at the ejection position based on the set recording conditions and the position information from the head position detection device and ejects the ink from the ink ejection port;
A recording position detecting device capable of detecting the recording position of the ink landed on the recording medium;
When the ink is ejected from the recording head under different conditions, the ejection speed of the ejected ink is calculated based on the interval between the recording positions of the ink detected by the recording position detection device, and based on the calculated ejection speed of the ink And a correction device for correcting the recording condition set in the control device.   The correction device detects ink that is detected by the recording position detection device when ink is ejected from the recording head that reciprocates in the main scanning direction with respect to the recording medium at the same ejection position during forward operation and backward operation, respectively. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus is configured to calculate an ejection speed of the ejected ink based on an interval between the recording positions.   The correction device detects the ink detected by the recording position detection device when ink is discharged at the same discharge position from the recording head that moves in the same direction in the main scanning direction with respect to the recording medium. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus is configured to calculate an ejection speed of the ejected ink based on an interval between recording positions.   4. The correction device according to claim 1, wherein when the ink ejection speed is calculated based on an interval between ink recording positions, the correction device performs the calculation according to an expression including an exponential function as a term of air resistance. The ink jet recording apparatus according to any one of the above.   The correction device corrects the ink ejection timing after changing the moving speed based on the ink ejection speed calculated under the recording conditions before changing the moving speed when changing the moving speed of the recording head to a different moving speed. The inkjet recording apparatus according to any one of claims 1 to 4, wherein the inkjet recording apparatus is configured to perform the following. When a plurality of the recording heads are provided,
The correction device calculates an ink ejection speed for each of the plurality of recording heads so that the recording positions of the ink on the recording medium are the same in the main scanning direction based on the calculated ejection speeds of the ink. The inkjet recording apparatus according to claim 1, wherein the ejection timing is corrected for each recording head. The recording head is configured to be able to change the ejection speed of the ejected ink according to the change of the applied drive voltage,
7. The correction device according to claim 1, wherein the correction device is configured to correct a driving voltage to be applied to the recording head by the control device based on the calculated ink ejection speed. An ink jet recording apparatus according to claim 1.   The correction device uses a linear function as a relational expression between the ejection speed and the drive voltage when the control device corrects the drive voltage to be applied to the recording head based on the calculated ink ejection speed. The inkjet recording apparatus according to claim 7, wherein the inkjet recording apparatus is configured to calculate a correction value of the drive voltage. The recording head is configured to be able to change the ejection speed of the ejected ink according to the change in the temperature of the ink inside,
9. The correction device according to claim 1, wherein the correction device is configured to correct the temperature of the ink in the recording head to be maintained by the control device based on the calculated ink ejection speed. The ink jet recording apparatus according to any one of the above. A transport device that transports the recording medium in the sub-scanning direction during recording,
The correction device is configured to detect an interval between ink recording positions by causing ink to land on a stationary recording medium without driving the transport device when calculating the ink ejection speed. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is provided.   The ink jet recording apparatus according to claim 1, wherein a photocurable ink is used as the ink.

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