JP2007144775A - Inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recorder which can carry out highly precise image recording while suppressing a decrease of the productivity to the minimum even when delivering defective nozzles are partly included. <P>SOLUTION: The inkjet recorder 1 is equipped with both a recording head 6 with a plurality of nozzles 16 which deliver onto a recording medium 2 ink that undergoes a phase change to a solid by irradiation with active energy rays or temperature change, and a recording medium conveying mechanism 12 which relatively moves a positional relationship between the recording head 6 and the recording medium 2. In the inkjet recorder 1 which carries out recording to form one band by scanning the recording head 6 by a plurality of the number of times, a control part 8 is prepared which divides a nozzle region where the nozzles 16 are arranged to the number of scans necessary for forming one band, and which determines whether or not to use the nozzle region for image recording according to a delivering state of the nozzle region where the last scan is carried out among the necessary scans for forming one band. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus that performs image recording using ink that is cured by irradiation with active energy rays.

  In general, an ink jet recording apparatus (hereinafter, referred to as “ink jet recording apparatus”) is known as an ink jet recording apparatus that can flexibly meet the demand for a small variety of products. An ink jet recording apparatus records an image on a recording medium by ejecting ink from a nozzle provided on the surface of the recording head facing the recording medium, and landing and fixing on the recording medium. Conventional gravure printing Unlike the image recording means based on the system or flexographic printing system, it does not require a plate making process, and therefore can easily and quickly respond to a small amount of demand. In addition, there is an advantage that color image recording can be easily performed by using multi-color ink with less noise.

  Furthermore, in recent years, as an ink jet recording apparatus compatible with various recording media, for example, a photocurable ink containing a photoinitiator having a predetermined sensitivity to light such as ultraviolet rays is used to land on the recording medium. 2. Related Art An ink jet recording apparatus using a photocurable ink that cures ink and fixes it on a recording medium by irradiating the ink with light is known (for example, see Patent Document 1). Inkjet recording apparatuses that perform recording using ink that is cured by irradiating active energy rays, such as inkjet recording apparatuses that use such photo-curable ink, cause the ink to be instantaneously cured by irradiation of active energy rays. In addition, there is little ink permeation and bleeding into the recording medium, and image recording can be performed not only on plain paper but also on a recording medium such as a film such as a resin or the like that does not have an ink receiving layer and has no ink absorption property, or metal. Is possible.

  However, in a recording head used in such an ink jet recording apparatus, if the nozzles are defectively ejected due to ink ejection bends, nozzle clogging, or the like, there is a risk of causing a problem in image recording.

Therefore, conventionally, the position of the defective discharge nozzle is stored in advance, and the location of the defective discharge nozzle is transferred to the control device when generating the print data, and a mask image that does not use the defective nozzle is generated during the print data generation process by the control device. When a printing failure occurs due to a method to be created (see, for example, Patent Document 2) or a defective nozzle, the normal nozzle is moved to the printing position of the defective discharge nozzle, and the defective printing portion is moved by the normal nozzle. A technique for performing correction printing (reprinting) (for example, see Patent Document 3) is known. It has also been proposed to provide an optical detection means for detecting defective nozzles (see, for example, Patent Document 4).
JP 2001-310454 A JP 2004-17529 A JP 2004-202962 A JP 2001-314533 A

  However, when an image is recorded by a plurality of scans in an ink jet recording apparatus that performs recording using ink that is cured by irradiation with an active energy ray, among the scans necessary to form one band, The discharge state of the nozzle area that performs the last scan greatly affects the image finish. In this regard, the technique described in Patent Document 2 performs image recording without using a discharge failure nozzle uniformly without considering whether a discharge failure occurs in a portion that affects the image. However, there is a problem that the recording speed is lowered and the productivity is lowered.

  In addition, as in the technique described in Patent Document 3, a technique for moving a normal nozzle to an area to be printed with a defective nozzle is not realized unless the movement accuracy of the recording head is high. However, even if it is difficult to achieve, there is a problem that the device cost becomes high.

  Therefore, the present invention has been made to solve the above-described problems, and performs high-definition image recording while minimizing a decrease in productivity even when there are defective ejection nozzles in part. An object of the present invention is to provide an ink jet recording apparatus capable of performing the above.

In order to solve the above problems, an ink jet recording apparatus according to claim 1 includes a recording head including a plurality of nozzles that discharge ink onto a recording medium that changes in phase to solid upon irradiation with active energy rays or a temperature change. An inkjet recording apparatus that performs recording so as to form one band by scanning the recording head a plurality of times, and a moving mechanism that relatively moves a positional relationship between the recording head and the recording medium. ,
The nozzle area in which the nozzles are arranged is divided into the number of scans necessary to form one band, and according to the ejection state of the nozzle area that performs the last scan among the scans necessary to form one band. And a control unit for determining whether or not to use the nozzle area for image recording.

  In the invention according to claim 1 having such a configuration, ink that changes in phase to solid by irradiation of active energy rays or temperature change is ejected from a plurality of nozzles of a recording head onto a recording medium, and is also moved by a moving mechanism. When performing recording so as to form one band by scanning the recording head a plurality of times while relatively moving the positional relationship between the recording head and the recording medium, the nozzle area in which the nozzles are arranged is changed to one Whether the nozzle area is used for image recording according to the ejection state of the nozzle area that performs the last scan among the scans necessary to form one band by dividing the number of scans necessary to form a band Whether or not is determined by the control unit.

According to a second aspect of the present invention, there is provided an ink jet recording apparatus comprising: a recording head comprising a plurality of nozzles that discharge ink onto a recording medium that changes its phase to solid upon irradiation with active energy rays or temperature change; and the recording head. An inkjet recording apparatus that performs recording so as to form one band by scanning the recording head a plurality of times, and a moving mechanism that relatively moves a positional relationship with the recording medium.
The nozzle area in which the nozzles are arranged is divided into the number of scans necessary to form one band, and the last scan among the scans necessary to form one band is the image recording of the recording head. And a control unit for controlling the recording head and the moving mechanism so as to be performed using a nozzle region in a discharge state suitable for the above.

  Therefore, according to the second aspect of the present invention, ink that changes its phase to solid by irradiation of active energy rays or temperature change is ejected from a plurality of nozzles of the recording head onto the recording medium, and the recording head and the recording medium are moved by the moving mechanism. In order to form one band in the nozzle area where the nozzles are arranged when recording is performed so as to form one band by scanning the recording head a plurality of times while relatively moving the positional relationship between The number of scans is divided into the number of scans required to form a single band, and control is performed so that the last scan among the scans necessary to form one band is performed using a nozzle region in the print head that is suitable for image printing. The unit controls the recording head and the moving mechanism.

  According to a third aspect of the present invention, in the ink jet recording apparatus according to the first or second aspect, a test pattern indicating a landing position of ink ejected from the nozzles is recorded using the entire area of the recording head. The control unit is characterized by determining the ejection state of the nozzle region of the recording head that records the last scan forming one band based on the recording result of the test pattern.

  In the invention according to claim 3 having such a configuration, the test pattern is recorded using the entire area of the recording head, and the control unit forms one band based on the recording result of the test pattern. The ejection state of the nozzle area of the recording head that records this scanning is determined.

According to a fourth aspect of the present invention, in the ink jet recording apparatus according to the first or second aspect of the present invention, the ink jet recording apparatus includes a detection mechanism that detects a discharge state of the nozzle.
The control unit controls the moving mechanism based on a detection result of the detection mechanism so that a nozzle region having the best ejection state is a nozzle region of the recording head that records the last scan forming one band. It is characterized by that.

  Therefore, the invention according to claim 4 includes a detection mechanism for detecting the discharge state of the nozzle, and based on the detection result of the detection mechanism, the last scan for forming one band in the nozzle region having the best discharge state. The control unit controls the moving mechanism so that the nozzle area of the recording head for recording is used.

  Furthermore, the invention according to claim 5 is the ink jet recording apparatus according to any one of claims 1 to 4, wherein the control unit has a nozzle region in which a level of a discharge state is a certain level or more. The moving mechanism is controlled so that the last scan for forming the nozzle is the nozzle area of the recording head for recording.

  As described above, in the invention according to claim 5, the control unit moves so that the nozzle area having a certain level of ejection state is a nozzle area of the recording head that records the last scan forming one band. It is designed to control the mechanism.

  Furthermore, the invention according to claim 6 is the ink jet recording apparatus according to any one of claims 1 to 4, wherein the control unit forms one band in a nozzle region having the best ejection state. The moving mechanism is controlled so that the nozzle region of the recording head that records the last scan to be performed is used.

  Therefore, according to the sixth aspect of the present invention, the control unit moves the moving mechanism so that the nozzle region with the best ejection state is the nozzle region of the recording head that records the last scan that forms one band. It comes to control.

  The invention according to claim 7 is the ink jet recording apparatus according to any one of claims 1 to 6, further comprising a drum rotating body that rotates while holding the recording medium on a peripheral surface, The moving mechanism is characterized by rotating the drum rotating body.

  Thus, according to the seventh aspect of the invention, the recording medium is held on the peripheral surface of the drum rotating body, and image recording is performed while rotating the drum rotating body by the moving mechanism.

  According to the first aspect of the present invention, when the discharge state of the nozzle region that performs the last scan that greatly affects the image finish among the scans necessary to form one band is not good. Since the nozzle area is not used for image recording, there is an effect that a high-definition image can be obtained.

  According to the second aspect of the present invention, among the scans necessary to form one band, the last scan that greatly affects the finish of the image is performed in a nozzle region having a good discharge state. There is an effect that a fine image can be obtained.

  According to the third aspect of the present invention, since the ejection state of the nozzle area that performs the last scan among the scans necessary for forming one band is grasped by recording the test pattern, it is simple and reliable. In addition, since the discharge state of the nozzle region can be grasped and control is performed according to the grasped discharge state, there is an effect that high-definition image recording can be performed.

  According to the fourth aspect of the invention, since the detection state of the nozzle region that performs the last scan among the scans necessary to form one band is detected by the detection mechanism, the discharge state of the nozzle region is accurately detected. Since the control is performed in accordance with the grasped discharge state, there is an effect that high-definition image recording can be performed.

  According to the fifth aspect of the present invention, the last scan that greatly affects the image finish is recorded among the scans necessary to form a single band in a nozzle region having a certain level of ejection state. Since the nozzle area of the recording head to be used is used, there is an effect that high-definition image recording can be performed.

  According to the sixth aspect of the present invention, the recording for recording the last scan that greatly affects the image finish among the scans necessary to form one band in the nozzle region having the best ejection state. Since the nozzle area of the head is used, there is an effect that high-definition image recording can be performed.

  According to the seventh aspect of the invention, since image recording is performed while the recording medium is supported on the drum rotating body, scanning in the sub-scanning direction can be controlled with high accuracy, and high-definition image recording is possible. There is an effect that can be performed.

  Hereinafter, a first embodiment of an ink jet recording apparatus according to the present invention will be described with reference to FIGS. 1 to 6.

  First, as shown in FIG. 1, in the present embodiment, an ink jet recording apparatus 1 is an ink jet recording apparatus 1 based on a serial printing method. A platen 3 supported from the recording surface is provided.

  A bar-shaped guide rail 4 extending in the width direction of the recording medium 2 is provided above the platen 3. A carriage 5 is supported on the guide rail 4, and the carriage 5 is driven in the width direction of the recording medium 2 (hereinafter “main scanning”) along the guide rail 4 by a carriage drive mechanism 11 (see FIG. 3) as a head scanning unit. (Referred to as direction X)).

  Further, the inkjet recording apparatus 1 includes a recording medium conveyance mechanism 12 (see FIG. 3) that includes a plurality of conveyance rollers 15 and the like, and that sends the recording medium 2 in the sub-scanning direction Y orthogonal to the main scanning direction X. It has been. The recording medium conveyance mechanism 12 rotates the conveyance roller 15 to repeat conveyance and stop of the recording medium 2 in accordance with the operation of the carriage 5 during image recording, and to move the recording medium 2 upstream in the sub-scanning direction Y. It is conveyed intermittently from the downstream to the downstream side.

  As shown in FIG. 1, the carriage 5 corresponds to each color (black (K), cyan (C), magenta (M), and yellow (Y)) used in the ink jet recording apparatus 1 in the present embodiment. Four recording heads 6 are mounted. The recording heads 6 are formed in a substantially rectangular parallelepiped shape, and are arranged side by side so that their longitudinal directions are parallel to each other. The ink used in the inkjet recording apparatus 1 is not limited to this, and for example, color ink such as light yellow (LY), light magenta (LM), light cyan (LC) or transparent ink can be used. . In this case, the recording head 6 corresponding to each ink is mounted on the carriage 5.

  The surface of the recording head 6 facing the recording medium 2 is an ink ejection surface in which a plurality of nozzles 16 are formed in a row along the longitudinal direction of the recording head 6, as shown in FIG. The recording head 6 is adapted to eject ink from the nozzles 16 respectively. In this embodiment, the ink jet recording apparatus 1 records one band by six scans as will be described later, and is an area in which the nozzles 16 are provided (hereinafter referred to as “nozzle area”). For example, as shown in FIG. 2, the nozzle area is divided into six areas A to F, and the ejection of ink is controlled for each nozzle area by a control unit 8 (see FIG. 3) described later. ing.

  Further, on both sides of the recording head 6 provided as a group, an ejection detection sensor 13 is provided as a detection mechanism for detecting the ejection state of each nozzle 16 of the recording head 6. The ejection detection sensor 13 is, for example, an optical sensor including a light emitting unit 13a that emits light by a laser or an LED, and a light receiving unit 13b that includes a light receiving element that senses light emitted from the light emitting unit 13a. A light emitting portion 13a is provided downstream of the recording head 6 in the main scanning direction X so as to sandwich the recording head 6 provided, and a light receiving portion 13b is provided on the upstream side of the main scanning direction X, and a light emitting surface of the light emitting portion 13a (not shown). And the light receiving surface (not shown) of the light receiving portion 13b are arranged so as to face each other.

The light receiving unit 13b receives the light emitted from the light emitting unit 13a on the light receiving surface, but the ink is ejected from the recording head 5 and the light emitted from the light emitting unit 13a is blocked by the ejected ink. And the light-receiving part 13b cannot receive the light irradiated from the light emission part 13a. Therefore, it is possible to detect whether ink has been ejected from the recording head 5 based on the amount of light received by the light receiving unit 13b.
The arrangement and configuration of the ejection detection sensor 13 are not limited to those exemplified here, and the ejection detection sensor 13 is arranged at a position other than the one exemplified here as long as it can detect the presence or absence of ink ejection. Alternatively, the ejection detection sensor 13 may be provided for each recording head 6. Various detection means other than the optical sensor may be applied as the discharge detection sensor 13.

  Inside the carriage 5 and upstream of the moving direction of the carriage 5 during image recording (the arrow X direction shown in FIG. 1), ultraviolet rays are used as active energy rays for curing and fixing the ink ejected and landed on the recording medium 2. An ultraviolet irradiation device 7 is disposed as an irradiation device for irradiating.

  The ultraviolet irradiation device 7 has an ultraviolet light source (not shown) that irradiates ultraviolet rays. As this ultraviolet light source, for example, a high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, a semiconductor laser, a cold cathode tube, an excimer lamp, or an LED (Light Emitting Diode) can be applied. It is not limited to what was illustrated to.

  The arrangement of the ultraviolet irradiation device 7 is not limited to this, and the ultraviolet irradiation device 7 may be provided between the recording heads 6. The ultraviolet irradiation device 7 is not limited to being mounted on the carriage 5, and may be provided outside the carriage 5.

Here, the ink used in this embodiment will be described.
The ink used in the present embodiment is an ultraviolet curable ink having a property of being cured by being irradiated with ultraviolet rays as active energy rays, and contains at least a polymerizable compound (including a known polymerizable compound) as a main component. ), A photoinitiator, and a coloring material. The photocurable ink is roughly classified into a radical polymerization ink containing a radical polymerizable compound as a polymerizable compound and a cationic polymerization ink containing a cationic polymerizable compound. Both inks are included in this embodiment. Each can be applied as an ink to be used. Further, a hybrid ink in which radical polymerization ink and cation polymerization ink are combined may be applied as the ink used in this embodiment. However, since cationic polymerization inks that have little or no inhibitory action on polymerization reaction due to oxygen are superior in functionality and versatility, it is particularly preferable to use cationic polymerization inks. The cationic polymerization ink is a mixture containing at least a cationic polymerizable compound such as an oxetane compound, an epoxy compound, and a vinyl ether compound, a photocationic initiator, and a coloring material.

  Further, as the recording medium 2, a recording medium 2 made of various materials such as various papers such as plain paper, recycled paper, glossy paper, various fabrics, various non-woven fabrics, resin, metal, and glass can be applied. As the form of the recording medium 2, various forms such as a roll form, a cut sheet form, and a plate form can be applied.

  Next, the control configuration of the inkjet recording apparatus 1 according to the present embodiment will be described with reference to FIGS. 3 to 6.

  As shown in FIG. 2, the inkjet recording apparatus 1 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores various control programs, and a RAM (Random Access Memory) that temporarily stores image data and the like. ) (Both not shown) and the like are provided. The control unit 8 develops a control program recorded in the ROM in a work area of the RAM and executes it by the CPU.

  Further, the inkjet recording apparatus 1 has an input unit 10 for inputting the type of the recording medium 2 and image recording conditions, and information input from the input unit 10 is sent to the control unit 8. Yes. The input unit 10 is, for example, a keyboard or an operation panel. The user operates the input unit 10 to select and set various image recording conditions such as the type of recording medium 2 used for image recording, a desired image recording speed, and resolution. Can be done.

  The control unit 8 controls the carriage drive mechanism 11 to reciprocate the carriage 5 in the main scanning direction X, and intermittently conveys the recording medium 2 in the sub-scanning direction Y in accordance with the operation of the carriage 5. The operation of the recording medium transport mechanism 12 is controlled.

  Furthermore, image data related to a recorded image is sent to the control unit 8 from an external device (not shown). The control unit 8 is based on the sent image data, information input from the input unit 10, and the like. Then, the recording head 6 is operated. Accordingly, an appropriate amount of ink is ejected from each recording head 6, and a predetermined image is recorded on the recording medium 2.

  The control unit 8 controls the ultraviolet irradiation device 7 to irradiate the ink ejected on the recording medium 2 with ultraviolet rays.

  In addition, a detection result detected by the ejection detection sensor 13 is sent to the control unit 8, and the control unit 8 selects one of the nozzle areas of the recording head 6 based on the sent result. A nozzle region for ejecting ink in the last scan for forming a band is determined.

  In the present embodiment, as shown in FIG. 4, the inkjet recording apparatus 1 scans one band six times when the feeding width of the recording medium 2 conveyed by one conveyance is one band. Recording is to be done. When all the nozzles 16 are in a normally ejectable state, for example, the uppermost band of the recording medium 2 in FIG. 4 performs the first scanning along the main scanning direction X and the recording head 6 Image recording for the first scan is performed by ink ejected from the nozzles 16 located on one end side (nozzle region A). In addition, image recording for the second scan is performed by ink ejected from the nozzles 16 located in the nozzle region B among the nozzles 16 of the recording head 6. Further, image recording of the third scan is performed by ink ejected from the nozzles 16 located in the nozzle region C among the nozzles 16 of the recording head 6. Similarly, the recording is completed for all pixels in one band by all six scans until the sixth scan image recording performed by the nozzle 16 located in the nozzle region F.

  On the other hand, when it is determined from the detection result of the discharge detection sensor 13 that there is a nozzle 16 with a discharge failure in the nozzle region F that should originally perform the sixth scan, the control unit 8 determines based on the detection result. Among the nozzle areas A to F, the nozzle area with the best ejection state is determined. Then, the nozzle region that is determined to have the best ejection state is determined as the nozzle region that performs the last scan (sixth scan) among the six scans necessary to form the one band. For example, when it is determined that the nozzle region E has the best ejection state, the control unit 8 performs ink ejection in the sub-scanning direction Y after the fifth ink ejection, as shown in FIG. The movement is temporarily stopped, and the recording medium transport mechanism 12 and the recording head 6 are controlled so that ink is ejected by the nozzle 16 located in the nozzle region E for the next sixth scan.

  Further, for example, when it is determined that the nozzle region C is the best ejected nozzle region, the control unit 8 controls the recording medium transport mechanism 12 after ink ejection of the fifth scan is performed. Thus, the recording medium 2 is once returned in the direction opposite to the sub-scanning direction Y, and the next sixth scan is performed by the nozzle 16 located in the nozzle region C.

  Note that the number of scans required to record one band is not limited to six. Furthermore, one band may be formed by a plurality of scans, or one band may be formed less than six times. In this case as well, it is determined that the discharge state is the best. The last scan in each band is performed by the nozzle 16 located in the nozzle region.

  In the case where one band is formed by a plurality of scans in the ink jet recording apparatus 1 that uses ink that is cured by irradiating with an active energy ray such as ultraviolet rays, the ink ejected at each scan is recorded on the recording medium 2. It piles up and hardens. Since the ink ejected in the last scan is stacked on the uppermost layer, the smoothness of the image surface formed by the landing state of the ink ejected in the last scan is affected. That is, for example, when one band is formed by six scans, a high-definition image with a smooth surface can be obtained as shown in FIG. 6A when ink is appropriately ejected by the sixth scan. it can. On the other hand, if there is an ejection failure during the sixth scan, the surface of the formed image is uneven as shown in FIG. 6B, and a high-definition image cannot be obtained. As described above, when one band is formed by a plurality of scans in the inkjet recording apparatus 1 that uses ink that is cured by irradiating with active energy rays, the last necessary for forming one band is used. The ink ejection state during scanning greatly affects image formation. Therefore, as shown in the present embodiment, it is possible to perform high-definition image recording with less unevenness on the surface of the image by performing the last scan with the nozzle region having the best ink ejection state.

  Next, the operation in this embodiment will be described.

  When image data input from an external device (not shown) is sent to the inkjet recording apparatus 1, the sent image data is stored in the RAM or the like of the control unit 8. When a signal for starting image recording is input from the input unit 10 by the user, the control unit 8 discharges ink from the recording head 6 and the discharge detection sensor 13 detects whether there is a defective nozzle. . The detection result is sent to the control unit 8. Based on the detection result, the control unit 8 has the best discharge state when there is a defective nozzle 16 in the nozzle region that should originally perform the sixth scan. A nozzle region is determined, and the nozzle 16 located in this nozzle region is determined to perform the last scan among the scans necessary for forming one band.

  When the nozzle area for performing the last scan is determined, the control unit 8 controls the recording medium transport mechanism 12 so that the recording medium 2 is sequentially transported intermittently from the upstream side to the downstream side in the sub-scanning direction Y. The control unit 8 controls the carriage drive mechanism 11 to scan the carriage 5 on the recording medium 2 along the main scanning direction X, and the control unit 8 controls each recording head 6 to obtain a predetermined value. A discharge amount of ink is discharged to a predetermined pixel. By irradiating the ink discharged onto the recording medium 2 with ultraviolet rays from the ultraviolet irradiation device 7, the ink is cured and fixed, and an image is recorded on the recording medium 2.

  As described above, according to the present embodiment, since the last scan that greatly affects the image is performed by the nozzle 16 in the nozzle region having the best ejection state, it is possible to form a high-definition image with a smooth surface. .

  Further, only when the ejection failure occurs in the nozzle area that performs the last scan that has a large effect on the image, the nozzle area is not used for image recording, so that a reduction in productivity can be minimized.

  Furthermore, since a smooth image without roughness can be obtained by selecting the nozzle region with the best ejection state as the nozzle region for the last scan and performing image recording, a high-definition image can be obtained with a relatively simple control configuration. Formation can be realized, and an increase in device cost can be suppressed.

Further, in the present embodiment, the ejection detection sensor 13 is provided to detect the presence or absence of the defective nozzle 16, but a test pattern is recorded using the entire area of the recording head 6 before image recording. The nozzle area of the recording head 6 that performs the last scan when forming one band may be determined according to the recording result. Horizontal stripes such as white stripes appearing in the test pattern indicate that there is a discharge defect such as a discharge bend or a nozzle missing in the nozzle recording the portion.
Therefore, for example, when the test pattern of the recording head 6 when the nozzle area of the recording head 6 is divided into six areas A to F is as shown in FIG. It can be determined that the portion corresponding to the nozzle region E shown in FIG. Therefore, in this case, the nozzle region E is set as the nozzle region of the recording head 6 that performs the last scanning when forming one band, and the last when forming one band by the nozzles 16 located in the nozzle region E. Scanning is performed.

Note that if ejection failure is recognized in any of the nozzle areas, the recording head 6 that performs the last scan when forming one band in an area where the ejection state of the nozzles 16 in the nozzle area is equal to or higher than a certain level. The last scanning may be performed when one band is formed by the nozzles 16 located in this nozzle region.
In this case, for example, as a level of the discharge state suitable for performing the last scan when forming one band, the percentage of the nozzles 16 with defective discharge among the nozzles 16 provided in the nozzle region is below what percentage. In such a case, a value suitable as an area for the last scan is stored in advance in the ROM of the control unit 8 as a threshold value. Then, the control unit 8 determines the nozzle region for performing the last scan when forming one band depending on whether or not the detected ejection state of each nozzle region exceeds the threshold value.

  Further, in the present embodiment, when there is a discharge failure in the nozzle region that performs the last scan when forming one band, the nozzle region is not used. Used for scanning that does not affect the image quality relatively (for example, scanning from the first time to the fifth time in the case of forming one band in 6 scans), and the last in other nozzle regions with good ejection state You may control to perform a scan. In this case, high-definition image formation can be realized without sacrificing productivity.

  In this embodiment, image recording is performed using ink that is cured by irradiation with ultraviolet rays. However, the ink is not necessarily limited to this, and for example, ultraviolet rays, electron beams, X-rays, visible The ink may be cured by irradiating light other than ultraviolet rays such as light rays and electromagnetic waves such as infrared rays. In this case, 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 are applied to the ink. In the case of using a photocurable ink that is cured by light other than ultraviolet light, a light source that emits the light is applied instead of the ultraviolet light source.

  In the present embodiment, the inkjet recording apparatus 1 configured to perform image recording using ink that is cured by irradiation with an active energy ray such as ultraviolet rays has been described as an example. However, the inkjet recording apparatus 1 is not limited thereto. For example, the present invention can be similarly applied to an inkjet recording apparatus 1 configured to perform image recording using ink that changes in phase by applying thermal energy to change temperature. In this case, instead of the ultraviolet irradiation device 7, a heating mechanism for heating the recording medium 2 is provided.

  In the present embodiment, the ink is ejected only when the carriage 5 is moved in one direction (main scanning direction X). However, the scanning is performed in any direction along the main scanning direction X. The recording may be performed by ejecting ink. In the case of such a configuration, the ultraviolet irradiation devices 7 are arranged on both sides of the recording head 6 mounted on the carriage 5 as a group.

  The recording head 6 used in the ink jet recording apparatus 1 according to the present invention may be an on-demand system or a continuous system. In addition, as a discharge method, for example, an electro-mechanical conversion method (for example, a single cavity type, a double cavity type, a bender type, a piston type, a shear mode type, a shared wall type, etc.), an electro-thermal conversion method (for example, , Thermal ink jet type, bubble jet (registered trademark) type), electrostatic suction type (for example, electric field control type, slit jet type, etc.) and discharge type (for example, spark jet type, etc.) May be used.

  In addition, it is needless to say that the present invention is not limited to the above embodiment and can be modified as appropriate.

  Next, a second embodiment of the ink jet recording apparatus according to the present invention will be described with reference to FIGS. In the following, differences from the first embodiment will be particularly described.

  As shown in FIGS. 8 and 9, the ink jet recording apparatus 20 according to the present embodiment supports a recording medium 2 fed from a paper feeding unit (not shown) and carried into the ink jet recording apparatus 20 from below. A flat plate-like member 21 that forms two conveyance paths is provided. A plurality of transport rollers 4 are provided on the transport path formed by the plate-like member 3 to rotate the recording medium 2 in the transport direction A by a drive mechanism (not shown).

  A substantially cylindrical drum rotating body 23 that holds the conveyed recording medium 2 on the outer peripheral surface is provided on the downstream side in the conveying direction A of the recording medium 2 in the plate-like member 21. The drum rotating body 23 includes a rotating shaft (not shown) provided so as to be substantially concentric with the central axis of the drum rotating body 23, and the rotating shaft is arranged so as to be orthogonal to the conveyance direction A of the recording medium 2. Yes. The drum rotating body 23 rotates in a predetermined rotation direction (hereinafter referred to as “main scanning direction X”) that is a circumferential direction of the drum rotating body 23 by rotating a rotation shaft by a rotating mechanism 24 (see FIG. 10) described later. It can rotate at a constant speed.

  The recording medium 2 that has been transported is pressed against the drum rotator 23 at a position below the drum rotator 23 and in contact with the downstream end of the plate-like member 21 in the transport direction A of the recording medium 2. A drawing roller 25 for drawing up is provided.

  Positions corresponding to the downstream end and the upstream end in the main scanning direction X of the recording medium 2 when the recording medium 2 is wound around the outer peripheral surface of the drum rotating body 23, which is the inner surface of the drum rotating body 23. Are provided with holding mechanisms 26 a and 26 b for holding the recording medium 2 on the outer peripheral surface of the drum rotating body 23.

  The holding mechanisms 26 a and 26 b are configured to generate static electricity on the outer peripheral surface of the drum rotator 23 by applying a voltage to the drum rotator 23, for example, and electrostatically attract the recording medium 2 onto the outer peripheral surface. The holding mechanisms 26a and 26b may be any mechanism as long as the recording medium 2 can be held on the outer peripheral surface of the drum rotating body 23, and the configurations of the holding mechanisms 26a and 26b are not limited to those illustrated here. For example, a holding mechanism that sandwiches the downstream end and the upstream end in the main scanning direction X of the recording medium 2 on the outer peripheral surface of the drum rotating body 23 may be provided. Further, for example, a plurality of suction holes are formed in the outer peripheral surface of the drum rotator 23, and the air inside the drum rotator 23 is sucked by a suction device (not shown), whereby the recording medium 2 is formed on the outer peripheral surface of the drum rotator 23. It is good also as a structure which adsorb | sucks.

  A discharge tray (not shown) for discharging the recording medium 2 released from being held by the holding mechanisms 26a and 26b is provided below the drum rotating body 23.

  In addition, as the recording medium 2 held by the drum rotating body 23, the recording medium 2 made of various materials can be applied as in the first embodiment. Various forms that can be held on the outer peripheral surface of the drum rotating body 23, such as a plate shape, are applicable. In the present embodiment, the recording medium 2 having a size smaller than the outer peripheral length of the drum rotating body 23 can be applied.

  A guide rail (not shown) extending in the sub-scanning direction Y orthogonal to the main scanning direction X of the recording medium 2 is provided at a position facing the outer peripheral surface of the drum rotating body 23. A carriage 27 is supported on the guide rail 5, and the carriage 27 can reciprocate in the sub-scanning direction Y along the guide rail by a carriage drive mechanism 28 (see FIG. 10) described later.

  A recording head 30 corresponding to each color (for example, yellow (Y), magenta (M), cyan (C), and black (K)) used in the ink jet recording apparatus 20 according to the present embodiment is provided on the carriage 27. They are arranged side by side so that the directions are parallel to each other. One surface of the recording head 30 is an ink ejection surface (not shown) provided with a plurality of nozzles (not shown) for ejecting ink. The recording head 30 is arranged so that the ink discharge surface faces the recording medium 2 on the drum rotating body 23, and the ink discharged from the recording head 30 is a predetermined position of the recording medium 2 on the drum rotating body 23. The position has been adjusted to land on. The ink applicable in the present embodiment is the same as that in the first embodiment. Further, the number and arrangement of the recording heads 30 are not limited to those exemplified here, and a configuration in which a plurality of recording heads 30 are provided in other arrangement patterns may be employed. Further, the color and type of ink used in the inkjet recording apparatus 20 are not limited to those exemplified as in the first embodiment.

  Also, ejection detection sensors 31 that detect ejection states of the nozzles of the recording head 30 are provided on both sides of the recording head 30 provided as a group, as in the first embodiment. In addition, it is the same as that of 1st Embodiment that the arrangement | positioning and structure of the discharge detection sensor 31 are not limited to what was illustrated here.

  A guide rail (not shown) extending in the sub-scanning direction Y is provided at a position facing the outer peripheral surface of the drum rotating body 23 and downstream of the carriage 27 in the main scanning direction X. The guide rail supports an ultraviolet irradiation device 32 having the same ultraviolet light source as in the first embodiment, and the irradiation device moving mechanism 33 (see FIG. 10), which will be described later, along the guide rail in the sub-scanning direction Y. It can move back and forth.

  Next, the control configuration of the inkjet recording apparatus 20 in the present embodiment will be described with reference to FIG.

  As shown in FIG. 10, the inkjet recording apparatus 20 is provided with a control unit 35 and an input unit 36 similar to those in the first embodiment, and the control unit 35 is based on a signal from the input unit 36. The operation of each part is controlled.

  Further, the control unit 35 rotationally drives the transport roller 22 to transport the recording medium 2 in the predetermined transport direction A, and the outer peripheral surface of the drum rotator 23 transports the transported recording medium 2 by the holding mechanisms 26a and 26b. When the image recording is completed, the holding is released. Further, the control unit 35 controls the carriage drive mechanism 28 to scan the carriage 27 in the sub-scanning direction Y, and also controls the rotation mechanism 24 to rotate the drum rotating body 23 to rotate the recording medium 2 in the main scanning direction X. To be transported.

  Further, the control unit 35 operates the recording head 30 based on image data sent from an external device (not shown), information input from the input unit 36, and the like. As a result, an appropriate amount of ink is ejected from the nozzles of each recording head 30, and a predetermined image is recorded on the recording medium 2.

  Further, the control unit 35 controls the irradiation device moving mechanism 33 to move the ultraviolet irradiation device 32 in the sub-scanning direction Y so as to correspond to the movement of the carriage 27, and operates the ultraviolet irradiation device 32 to operate the recording head 30. The ink ejected from the ink and landed on the recording medium 2 is irradiated with ultraviolet rays.

  In addition, the detection result and the like detected by the ejection detection sensor 31 is sent to the control unit 35 as in the first embodiment, and the control unit 35 receives the recording head based on the sent result. Of the 30 nozzle regions, the nozzle region that ejects ink in the last scan that forms one band is determined.

  That is, when it is determined from the detection result of the discharge detection sensor 31 that there is a nozzle with a defective discharge in the nozzle region where the last scan that originally forms one band is performed, the control unit 35 determines the nozzle region based on the detection result. Among them, the nozzle region with the best discharge state is determined. When one band is formed by six scans, the last scan (sixth scan) of the scans necessary to form the one band is determined for the nozzle region that is determined to have the best ejection state. ), And after the ink ejection for the fifth scan is performed, the movement of the carriage 27 in the sub-scanning direction Y is temporarily stopped, or the carriage 27 is temporarily moved in the direction opposite to the sub-scanning direction Y (in FIG. 9). After returning to the direction opposite to the arrow Y), the rotation mechanism 24 and the recording head 30 are controlled so that the ink ejection for the next sixth scan is performed by the nozzle located in the nozzle region where the ejection state is the best.

  As in the first embodiment, the number of scans required to record one band is not limited to six. Furthermore, one band may be formed by a plurality of scans, or one band may be formed less than six times. In this case as well, it is determined that the discharge state is the best. The last scan in each band is performed by the nozzle located in the nozzle region.

  Since other configurations are the same as those of the first embodiment, description thereof is omitted.

  Next, the operation in this embodiment will be described.

  When image data input from an external device (not shown) is sent to the inkjet recording apparatus 20, the sent image data is stored in the RAM of the control unit 35 or the like. When a signal for starting image recording is input from the input unit 36 by the user, the control unit 35 ejects ink from the recording head 30 and the ejection detection sensor 31 detects whether there is a defective ejection nozzle. . The detection result is sent to the control unit 35. The control unit 35 determines the nozzle region with the best discharge state based on the detection result, and is necessary for forming one band by the nozzles located in the nozzle region. It decides to perform the last scan among the scans.

  When the nozzle area for the last scan is determined, the control unit 35 controls the rotation mechanism 24 to rotate the drum rotating body 23 in the main scanning direction X, and the recording medium 2 is moved from the upstream side in the main scanning direction X. It is conveyed downstream. Further, the control unit 35 controls the carriage drive mechanism 28 to scan the carriage 27 on the recording medium 2 along the sub-scanning direction Y, and the control unit 35 controls each recording head 30 to perform a predetermined operation. The recording head 30 is scanned for the number of scans, and a predetermined amount of ink is ejected to a predetermined pixel. In the last scan required for forming one band, ink is ejected from the nozzles in the nozzle region that is determined to have the best ejection state, and the formation of one band is completed.

  The control unit 35 moves the ultraviolet irradiation device 32 in response to the movement of the carriage 27, and the ultraviolet rays are irradiated from the ultraviolet irradiation device 32 to the ink ejected onto the recording medium 2. As a result, the ink is cured and fixed, and an image is recorded on the recording medium 2. When the image recording is completed, the recording medium 2 is released from the holding mechanism 26a, 26b, separated from the outer peripheral surface of the drum rotating body 23, and discharged to the discharge tray.

  As described above, according to the present embodiment, since the last scan having a great influence on the image is performed by the nozzle in the nozzle region having the best ejection state, it is possible to form a high-definition image with a smooth surface. In particular, in the case of the inkjet recording apparatus 20 including the drum rotating body 23, the operation accuracy is high when the scanning of the carriage 27 in the sub-scanning direction Y is temporarily stopped or temporarily returned to the opposite direction, and the serial inkjet recording apparatus is provided. High-definition image formation can be realized more effectively than in the case of using.

  In addition, only when it is determined that there is a defective nozzle in the nozzle area where the last scan that originally forms one band is performed, the image recording is performed without using the nozzle area. It is possible to improve the productivity as compared to the case where the nozzle is not always used when there is a discharge failure in the nozzle.

  Furthermore, since a smooth image without roughness can be obtained by selecting the nozzle region with the best ejection state as the nozzle region for the last scan and performing image recording, a high-definition image can be obtained with a relatively simple control configuration. Formation can be realized, and an increase in device cost can be suppressed.

  In this embodiment, when it is determined by the discharge detection sensor 31 that there is a defective nozzle, the nozzle region with the best discharge state is selected, and the last band forming one band with the nozzles located in the nozzle region is selected. For example, when it is determined from the detection result of the discharge detection sensor 31 that there is a defective nozzle in the nozzle area where the last scan for forming one band is performed, the scanning in the sub-scanning direction Y is performed. The image may be recorded from the reverse while rotating in the opposite direction.

  That is, for example, when one band is formed by six scans, as shown in FIG. 11, recording is performed sequentially from the pixels that are normally recorded in the sixth scan, and the pixels that are normally recorded in the first scan are the last scan. Recording is performed at a certain sixth scan.

By recording in the reverse direction in this way, it is possible to prevent the last scan from being recorded in a nozzle region where there is a defective nozzle, and smoothing of the image surface can be realized.
Further, when performing such recording, it is used for scanning that has little influence on image quality even in a nozzle region where ejection failure has occurred (scanning other than the last scanning out of scanning necessary to form one band). Therefore, high-definition image formation can be realized without reducing productivity.

  Further, in the present embodiment, the presence or absence of a defective nozzle is detected by the ejection detection sensor 31, but as in the first embodiment, a test pattern is recorded by ejecting ink from all the nozzles of the recording head 30, From this test pattern, the presence or absence of a defective nozzle may be determined, and the nozzle region for performing the last scan for forming one band may be determined.

  Other than that, the present invention is not limited to the present embodiment, as in the first embodiment.

1 is a top view illustrating a configuration of a main part of a first embodiment of an ink jet recording apparatus according to the present invention. FIG. 3 is a diagram illustrating each nozzle region of a recording head of the ink jet recording apparatus according to the first embodiment. It is a principal block diagram showing an outline of a control configuration of the first embodiment of the ink jet recording apparatus according to the present embodiment. FIG. 6 is a diagram illustrating nozzle regions corresponding to a recording head that records each band when performing normal recording. FIG. 5 is a diagram illustrating nozzle regions corresponding to a recording head that records each band in a case where the last scanning recording is performed in a nozzle region having the best ejection state. FIG. 6A is a diagram illustrating the degree of ink overlap when the last scan is performed in a nozzle area where there is no ejection failure. FIG. 6B is a diagram illustrating the degree of ink overlap when the last scan is performed in a nozzle region where there is a discharge failure. FIG. 4 is a diagram illustrating a correspondence between a test pattern and a nozzle area of a recording head. It is the side view which showed the principal part structure of 2nd Embodiment of the inkjet recording device which concerns on this invention. It is the perspective view which showed the principal part structure of 2nd Embodiment of the inkjet recording device which concerns on this invention. It is a principal block diagram showing an outline of a control configuration of a second embodiment of the ink jet recording apparatus according to the present embodiment. FIG. 5 is a diagram illustrating nozzle areas corresponding to a recording head that records each band when recording is performed by rotating a drum rotating body in the reverse direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Recording medium 6 Recording head 7 Ultraviolet irradiation device 8 Control part 13 Discharge detection sensor 16 Nozzle 23 Drum rotary body X Main scanning direction Y Sub scanning direction

Claims (7)

Relative movement of the positional relationship between the recording head having a plurality of nozzles that discharge onto the recording medium ink that changes its phase to solid upon irradiation with active energy rays or temperature change, and the recording medium An inkjet recording apparatus that performs recording so as to form one band by scanning the recording head a plurality of times.
The nozzle area in which the nozzles are arranged is divided into the number of scans necessary to form one band, and according to the ejection state of the nozzle area that performs the last scan among the scans necessary to form one band. An ink jet recording apparatus comprising: a control unit that determines whether or not to use the nozzle area for image recording. Relative movement of the positional relationship between the recording head having a plurality of nozzles that discharge onto the recording medium ink that changes its phase to solid upon irradiation with active energy rays or temperature change, and the recording medium An inkjet recording apparatus that performs recording so as to form one band by scanning the recording head a plurality of times.
The nozzle area in which the nozzles are arranged is divided into the number of scans necessary to form one band, and the last scan among the scans necessary to form one band is the image recording of the recording head. An ink jet recording apparatus comprising: a control unit that controls the recording head and the moving mechanism so as to be performed using a nozzle region in a discharge state suitable for the above.   A test pattern indicating the landing position of the ink ejected from the nozzle is recorded using the entire area of the recording head, and the control unit performs the last scan to form one band based on the recording result of the test pattern. The inkjet recording apparatus according to claim 1, wherein an ejection state of the nozzle region of the recording head that records the ink is determined. A detection mechanism for detecting the discharge state of the nozzle,
The control unit controls the moving mechanism based on the detection result of the detection mechanism so that the nozzle area with the best ejection state is the nozzle area of the recording head that records the last scan that forms one band. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is an ink jet recording apparatus.   2. The control unit according to claim 1, wherein the control unit controls the recording head so that a nozzle region having a certain level of ejection state is a nozzle region of the recording head that records the last scan forming one band. The ink jet recording apparatus according to any one of claims 1 to 4.   2. The control unit according to claim 1, wherein the control unit controls the recording head so that a nozzle region having the best ejection state is set as a nozzle region of the recording head that records the last scan for forming one band. Item 5. The ink jet recording apparatus according to any one of Items 4. A drum rotating body that rotates while holding the recording medium on a peripheral surface;
The inkjet recording apparatus according to any one of claims 1 to 6, wherein the moving mechanism rotates the drum.

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