WO2007034641A1

WO2007034641A1 - Ink jet recorder

Info

Publication number: WO2007034641A1
Application number: PCT/JP2006/316214
Authority: WO
Inventors: Yoshihide Hoshino
Original assignee: Konica Minolta Medical & Graphic, Inc.
Priority date: 2005-09-22
Filing date: 2006-08-18
Publication date: 2007-03-29
Also published as: JPWO2007034641A1

Abstract

An ink jet recorder in which granular feeling of an image is suppressed as compared with prior art and occurrence of streaky image defect is prevented. The ink jet recorder (1) comprises rollers (10, 10) for carrying a recording medium (K) in the carrying direction X, a plurality of nozzle arrays (21, 31) consisting of a plurality of nozzles (20, ...) for ejecting ink of predetermined hue in the form of a liquid drop of first quantity toward the recording medium (K) carried by the carrying rollers (10, 10), and at least one nozzle array (41) consisting of a plurality of nozzles (40, ...) for ejecting ink of above-mentioned hue in the form of a liquid drop of second quantity smaller than the first quantity. The nozzle arrays (21, 31) and the nozzle array (41) are arranged side by side in the carrying direction X while respectively kept intersecting the carrying direction X, and the number of the nozzle arrays (21, 31) arranged in the carrying direction X is larger than the number of the nozzle arrays (41) arranged in the carrying direction X.

Description

Specification

Inkjet recording device

Technical field

The present invention relates to an ink jet recording apparatus that records an image on a recording medium.

Background art

Conventionally, as an apparatus for recording an image on a recording medium such as paper or cloth, there is an ink jet recording apparatus that records an image by ejecting ink from a nozzle of a recording head onto the recording medium (for example, Patent Document 1, Patent Document 1). 2).

[0003] By the way, in such an ink jet recording apparatus, the nozzles may be clogged, or the direction of the nozzles may be shifted due to a manufacturing error. If the size is small, streak-like defects occur in the image. On the other hand, if the ink droplet size is large, the occurrence of streak-like image defects can be prevented, but the graininess of the image becomes high.

[0004] Therefore, in a serial recording type inkjet recording apparatus that scans a recording head and records an image, the recording head scans the same area of the recording medium a plurality of times to record an image with a plurality of nozzles. By performing pass printing and multi-drop printing that ejects multiple ink droplets of different sizes to a single pixel, streak-like image defects are prevented and the graininess of the image is reduced. ing.

Patent Document 1: Japanese Patent Laid-Open No. 11-268355

Patent Document 2: Japanese Patent Laid-Open No. 2000-37888

Disclosure of the invention

Problems to be solved by the invention

[0005] In a line recording type ink jet recording apparatus that records an image with a recording head extending in the width direction of the recording medium while exerting force, the image graininess is reduced while preventing the occurrence of streak-like image defects. It cannot be lowered.

[0006] An object of the present invention is to provide an ink jet recording apparatus capable of suppressing the graininess of an image as compared with the conventional art and preventing the occurrence of streak-like image defects. Means for solving the problem

[0007] The invention described in claim 1 is an inkjet recording apparatus,

A transport device for transporting the recording medium in the transport direction;

A plurality of first nozzle rows configured by a plurality of first nozzle caps that eject ink of a predetermined hue onto the recording medium transported by the transport device as a first droplet amount; and the transport device At least one second nozzle configured by a plurality of second nozzles that ejects the ink of the predetermined hue as droplets having a second droplet amount smaller than the first droplet amount to the recording medium being conveyed. With columns,

The first nozzle row and the second nozzle row are arranged side by side in the transport direction in a state intersecting with the transport direction, respectively.

The number of the first nozzle rows arranged in the carrying direction is larger than the number of the second nozzle rows arranged in the carrying direction.

[0008] It should be noted that the hue is a hue, and the hue is the same even when the saturation and brightness are different, for example, when the content of the color material in the ink is different.

[0009] The invention according to claim 2 is an inkjet recording apparatus,

At least one first nozzle row composed of a plurality of first nozzle caps that eject ink of a predetermined hue as droplets of a first droplet amount onto a recording medium conveyed by the conveying device;

At least one of a plurality of second nozzle caps that ejects ink of the predetermined hue onto the recording medium transported by the transport device as droplets having a second droplet amount smaller than the first droplet amount. Two second nozzle rows,

The maximum recording rate of the first nozzle row is higher than that of the second nozzle row.

Here, the maximum recording rate is the maximum ratio of the number of virtual pixels to which ink should be ejected with respect to the total number of virtual pixels in a unit area when the recording medium is divided by virtual pixels.

[0011] The invention described in claim 3 is an ink jet according to claim 1 or 2. In the recording device,

The first content of the color material per unit volume of ink discharged from the first nozzle row cover is more than the second content of the color material per unit volume of ink discharged from the second nozzle row cover. Is also large.

[0012] The invention according to claim 4 is an inkjet recording apparatus,

A plurality of first nozzle forces configured to eject a predetermined hue of ink containing a first content of color material per unit volume as droplets onto a recording medium conveyed by the conveying device. A nozzle row;

A plurality of second inks ejecting the ink of the predetermined hue containing a color material having a second content smaller than the first content per unit volume as droplets to a recording medium conveyed by the conveyance device. At least one second nozzle row composed of two nozzle caps, and the first nozzle row and the second nozzle row are arranged side by side in the transport direction in a state of crossing the transport direction, respectively. ,

[0013] The invention according to claim 5 is an inkjet recording apparatus,

A plurality of first nozzle forces configured to eject ink of a predetermined hue containing a color material having a first content per unit volume as droplets onto a recording medium transported by the transport device are configured. 1 nozzle row,

The maximum recording rate of the first nozzle row is higher than that of the second nozzle row. [0014] The invention according to claim 6 is the ink jet recording apparatus according to any one of claims 1 to 5,

The plurality of first nozzles are:

Arranged in the intersecting direction intersecting the transport direction with a pitch P to constitute the first nozzle row n (n is an integer of 2 or more),

Among these n first nozzle rows, (n−l) first nozzle rows are offset by pZn in the intersecting direction with respect to the remaining one first nozzle row. .

[0015] The invention according to claim 7 is the ink jet recording apparatus according to any one of claims 1 to 6,

A photo-irradiating ink is ejected from the first nozzle row and the second nozzle row, and a light irradiation device is provided in a region where the ejected ink lands on a recording medium.

The invention described in claim 8 is an ink jet recording apparatus according to claim 7, wherein:

A light irradiation device is provided in a region that is interposed between the plurality of first nozzle rows and the ink ejected from the first nozzle rows lands on the recording medium.

[0016] The invention according to claim 9 is the ink jet recording apparatus according to any one of claims 1 to 8,

The first nozzle row and the second nozzle row for ejecting cyan hue ink, the first nozzle row and the second nozzle row for ejecting magenta hue ink, and the yellow hue ink are ejected. The first nozzle row;

And the first nozzle row that ejects black hue ink.

[0017] The invention according to claim 10 is the ink jet recording apparatus according to claim 9,

A light irradiation device is provided in a region that is interposed between nozzle rows that eject inks of different hues and that the ink ejected from the first nozzle row lands on a recording medium.

The invention's effect

[0018] According to the invention described in any one of claims 1 to 10, the graininess of the image is suppressed to be lower than that in the past, and the occurrence of streak-like image defects is prevented. Can wear.

Brief Description of Drawings

FIG. 1 is a plan view showing a schematic configuration of an ink jet recording apparatus according to the present invention.

FIG. 2 is a bottom view of a recording head and an irradiation apparatus.

FIG. 3 is a plan view showing a schematic configuration of the ink jet recording apparatus according to the present invention.

FIG. 4 is a bottom view of a recording head and an irradiation apparatus.

FIG. 5 is a diagram for explaining a maximum recording rate of a nozzle row.

Explanation of symbols

[0020] 1, 1A, IB, 1C Inkjet recording device

9 Irradiation device

10 Conveying roller (Conveying device)

20, 23 Nos, Nore (1st Nos, Nore)

21, 22, 24, 25 Nos, Nore U (1st Nos, Nore U)

31, 32, 34, 35 Nos, Nore U (1st Nos, Nore U)

40, 43 Nos, Nore (2nd Nos, Nore)

41, 42, 44, 45 Nos, Nore U (2nd Nos, Nore U)

K recording medium

X Transport direction

BEST MODE FOR CARRYING OUT THE INVENTION

[0021] <First embodiment>

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view showing a schematic configuration of an ink jet recording apparatus 1 according to the present invention.

As shown in this figure, the ink jet recording apparatus 1 includes transport rollers 10 and 10 as a transport apparatus in the present invention.

The conveyance rollers 10 and 10 convey the recording medium K in the conveyance direction X, and each have a rotation axis in the width direction Y of the recording medium K.

A platen 11 is interposed between the transport rollers 10 and 10. The platen 11 is configured so that the recording medium K conveyed by the conveying rollers 10 and 10 can be transferred from the back side in the present embodiment. Supports the downward force flatly.

[0026] Above the platen 11, four recording heads 2a to 2d, four recording heads 3a to 3d, two recording heads 4a and 4b, and a force conveying direction X are arranged in this order.

The recording heads 2a to 2d and the recording heads 3a to 3d include a plurality of head blocks 26 and 36 arranged in a staggered manner in the width direction Y of the recording medium K! /.

As shown in FIG. 2, each head block 26, 36 has a plurality of nozzles 20,.

The plurality of nozzles 20,... Are the first nozzles in the present invention, and the ink of a predetermined hue is used as the first droplet amount for the recording medium K conveyed by the conveying rollers 10 and 10. It is designed to discharge. In this embodiment, the nozzles 20,... Of the recording heads 2a, 3a are black ink, the nozzles 20,... Of the recording heads 2b, 3b are cyan ink, and the nozzles 20 of the recording heads 2c, 3c. ,… Ejects magenta ink, and nozzles 2d, 3d 20, 20, etc., eject yellow ink!

In addition, the nozzles 20,... Are arranged at a pitch p in the width direction Y of the recording medium K, and constitute nozzle rows 21, 31 as the first nozzle row in the present invention. Among these, each nozzle row 31 of the recording heads 3a to 3d is aligned with the nozzle row 21 of the recording heads 2a to 2d in the transport direction X, and only pZ2 in the width direction Y of the recording medium K with respect to the nozzle row 21 It is offset.

As shown in FIG. 1, the recording heads 4a, 4b include a plurality of head blocks 46,... Arranged in a staggered manner in the width direction Y of the recording medium K.

As shown in FIG. 2, each head block 46,... Has a plurality of nozzles 40,.

The plurality of nozzles 40,... Are the second nozzles in the present invention, and the ink of a predetermined hue is less than the first droplet amount with respect to the recording medium K conveyed by the conveying rollers 10, 10. It is designed to be ejected as a second droplet amount. The content of the color material per unit volume of ink ejected from the nozzle 40 (hereinafter referred to as the second content) is the content of the color material per unit volume of ink ejected from the nozzle 20. (Hereinafter referred to as the first content). In the present embodiment, the nose of the recording head 4a 40, ... discharges light cyan ink as cyan hue ink, and nozzle 40, ... of the recording head 4b discharges light magenta ink as magenta hue ink.

Further, the nozzles 40,... Are arranged at a pitch p in the width direction Y of the recording medium K, and constitute a nozzle row 41 as the second nozzle row in the present invention.

Each nozzle row 41 is aligned with the nozzle row 21 of the recording heads 2a to 2d in the transport direction X. As a result, for cyan and magenta hue inks, the number of nozzle rows 41 arranged in the transport direction X, that is, the number of nozzle rows ejecting droplets of the second droplet amount is 1, and the nozzle rows 21, The number of nozzles 31, that is, the number of nozzle rows that eject droplets of the first droplet amount is 2. On the other hand, for the yellow and black hue inks, only the nozzle rows 21 and 31 that discharge the first droplet amount of the droplets are arranged in the transport direction X, so the second droplet amount of the droplet is discharged. Compared to the case where more nozzle rows are arranged, the number of nozzle rows is reduced, and the inkjet recording apparatus 1 is downsized.

[0036] As shown in FIG. 1, each of the irradiation devices (lights) on the downstream side in the transport direction X with respect to the recording heads 2a to 2d, the recording heads 3a to 3d, and the recording heads 4a and 4b. (Irradiation device) 9 is installed. These irradiating devices 9, ... are intended to irradiate light on the lower recording medium K. The high-pressure mercury lamp, low-pressure mercury lamp, metal nitride lamp, black light, hot cathode tube, cold cathode tube, LED The light source 90 (see Fig. 2) such as an electrodeless lamp and an excimer lamp is provided.

[0037] A light shielding member (not shown) that shields the nozzles 20, 40 is disposed between the recording heads 2a to 2d, the recording heads 3a to 3d, the recording heads 4a and 4b, and the irradiation device 9. Preferably

Next, “ink” used in the present embodiment will be described.

[0039] The ink used in the present embodiment is, in particular, the "photo-curing system (No. 1)" selected from "photo-curing technology-resin", "initiator selection and blending conditions and measurement of degree of cure" evaluation (Technical Association information) J In Chapter 4), inks that are compatible with “curing systems using photoacid and base generators (Section 1)”, “light-induced alternating copolymerization (Section 2)”, etc. are applicable. It may be cured by radical polymerization. [0040] Specifically, the ink used in the present embodiment is an ultraviolet curable ink having a property of being cured by irradiation with ultraviolet rays as light, and a polymerizable compound (known polymerization) as a main component. An organic compound), a photoinitiator, and a coloring material. However, the photoinitiator may be excluded when an ink suitable for the above “light-induced alternating copolymerization (section 2)” is used as the ink used in the present embodiment.

[0041] The photocurable (photocurable) ink is roughly classified into a radically polymerizable ink containing a radically polymerizable compound and a cationically polymerizable ink containing a cationically polymerizable compound as a polymerizable compound. However, both types of inks can be applied as inks used in this embodiment, and hybrid inks in which radical polymerization ink and cationic polymerization ink are combined are applied as inks used in this embodiment. Even so.

In spite of this, the cationic polymerization ink, which has less or no inhibition of the polymerization reaction by oxygen, is superior in functionality and versatility. Therefore, in this embodiment, a cationic polymerization ink is used in particular.

[0043] The cationic polymerization ink used in the present embodiment specifically includes a cationically polymerizable compound such as an oxetane compound, an epoxy compound, and a bull ether compound, and a light power. It is a mixture containing at least a thione initiator and a coloring material, and has a property of being cured by irradiation with ultraviolet rays as described above.

Incidentally, the ink (including radical polymerization ink, cationic polymerization ink, and hybrid ink) used in the present embodiment is cured by irradiation with ultraviolet rays as described above, but is not necessarily limited. However, the present invention is not limited to this, and it may be hardened by irradiation with light other than ultraviolet rays. Here, “light” is light in a broad sense and includes electromagnetic waves such as ultraviolet rays, electron beams, X-rays, visible rays, and infrared rays. That is, the ink used in the present embodiment 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. May apply V ヽ. In the case where a photocurable ink that is cured by light other than ultraviolet rays is used as the ink used in the present embodiment, a light source that irradiates the light must be applied as the irradiation unit according to the present invention.

Next, the “recording medium K” used in the present embodiment will be described. [0046] The recording medium K used in the present embodiment includes various papers such as plain paper, recycled paper, and glossy paper, various fabrics, various non-woven fabrics, resin, metal, glass, which are applied to ordinary inkjet recording apparatuses. A recording medium having a material strength such as the above can be applied. As the form of the recording medium ridge, a roll shape, a cut sheet shape, a plate shape and the like are applicable.

[0047] In particular, as the recording medium used in the present embodiment, a transparent or opaque non-hygroscopic resin film used for soft packaging can be applied. Specific types of resin used for resin film include polyethylene terephthalate, polyester, polyolefin, polyamide, polyesteramide, polyetherenole, polyimide, polyamideimide, polystyrene, polycarbonate, poly-ρ-phenol sulfide, polyether ester. , Polychlorinated butyl, poly (meth) acrylic acid ester, polyethylene, polypropylene, nylon, etc. are applicable, and also a copolymer of these resins, a mixture of these resins, and a crosslinked one of these resins Etc. are also applicable. In particular, the selected polyethylene resin terephthalate, polystyrene, polypropylene, or nylon as the type of resin for the resin film is the transparency, dimensional stability, rigidity, and environmental impact of the resin film. 'Preferred in terms of cost and the like 2 ~: It is preferable to use a resin film having a thickness of LOO m (preferably 6 to 50 µm). Further, surface treatments such as corona discharge treatment and easy adhesion treatment may be applied to the surface of the resin film support. Further, as the recording medium K used in the present embodiment, opaque known recording media such as various papers whose surfaces are coated with resin, films containing pigments, foamed films and the like are also applicable.

[0048] Next, the operation of the inkjet recording apparatus 1 during image recording will be described.

First, the recording medium K is transported in the transport direction X by the rotation of the transport rollers 10 and 10.

Next, the recording heads 2a to 2d, the recording heads 3a to 3d, and the recording heads 4a and 4b eject ink onto the recording medium K in the region supported by the platen 11. Regarding the hues of cyan and magenta, the width direction of the recording medium K is opposite to the nozzle rows 21 and 31 of the recording heads 2b and 2c and the recording heads 3b and 3c and the nozzle row 41 of the recording heads 4a and 4b. It is preferable to share the dot formation alternately in the Y and transport direction X!

[0051] At this time, recording is performed more than the second droplet amount of the droplets discharged from the nozzle array 41 of the recording heads 4a and 4b. Since the first droplet volume of the droplets ejected from the nozzle rows 21 and 31 of the heads 2a to 2d and the recording heads 3a to 3d is large, the nozzle row 41 Compared with the case of recording, large-diameter dots are formed, and the dot interval is reduced. In addition, since the nozzle rows 21 and 31 are arranged more in the transport direction than the nozzle row 41, the area recorded by the nozzle rows 21 and 31, that is, the dot interval is smaller than when the same number is arranged. The area becomes wider. On the other hand, since the second droplet amount of the droplets discharged from the nozzle row 41 is smaller than the first droplet amount of the droplets discharged from the nozzle rows 21 and 31, cyan and In the magenta hue area, dots having a smaller diameter are recorded as compared with the case where the nozzle arrays 21 and 31 are used.

[0052] Further, since the nozzle rows 21 and 31 are offset by pZ2 in the width direction Y of the recording medium K, in the area of each hue recorded by these nozzle rows 21 and 31, the space between the dots is filled. Complementary ink droplets will land.

[0053] The irradiation device 9 irradiates the recording medium K with light on the downstream side of the recording heads 2a to 2d, the recording heads 3a to 3d, and the recording heads 4a and 4b. As a result, the ink landed on the recording medium K is cured, and an image is recorded on the surface of the recording medium K.

[0054] At this time, since the irradiation device 9 is interposed between the nozzle rows 21, 31, ink droplets ejected from the nozzle rows 21, ..., that is, ink droplets having a larger droplet amount than the nozzle row 41 Are prevented from being connected on the surface of the recording medium K.

[0055] According to the ink jet recording apparatus 1 as described above, the dot interval can be reduced in each hue region recorded by the nozzle rows 21 and 31, thus preventing the occurrence of streak-like image defects. can do. In addition, by arranging the nozzle rows 21 and 31, such a region can be widened, and thus it is possible to reliably prevent the occurrence of streak-like image defects. In addition, by offsetting the nozzle rows 21 and 31, ink droplets can be landed in a complementary manner, so that the occurrence of streak-like image defects due to variations in the ink droplet landing positions can be prevented more reliably. can do.

In addition, in the cyan and magenta hue regions recorded by the nozzle row 41, small diameter dots can be recorded, so that the graininess of the image can be reduced. In addition, the amount of ink discharged from the nozzle row 41 is larger than the first content of the color material in the ink discharged from the nozzle rows 21, 31. Since the second content of the color material in the screen is small, recording the highlight portion of the image with the nozzle array 41 can surely reduce the graininess of the light and illite portions.

Further, the irradiation device 9 between the nozzle rows 21 and 31 can prevent the ink droplets from these nozzle rows 21 and 31 from being connected on the recording medium K, so that photocuring can be performed. Even in the case of this type of ink jet recording apparatus, the graininess of the image can be suppressed to a lower level, and the occurrence of streak-like image defects can be more reliably prevented.

Accordingly, it is possible to suppress the graininess of the image as compared with the conventional case and to prevent the occurrence of streak-like image defects.

Next, a modification of the first embodiment will be described. The same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

FIG. 3 is a plan view showing a schematic configuration of the ink jet recording apparatus 1A according to the present invention.

[0060] As shown in this figure, the ink jet recording apparatus 1A according to the present modification includes four recording heads 2e to 2h and two recording heads 4e and 4f in this order in the transport direction X.

The recording heads 2e to 2h include a plurality of head blocks 27,... Arranged in a staggered manner in the width direction Y of the recording medium K. As shown in FIG. 4, each head block 27 has a plurality of nozzles 20 on the lower surface, and the plurality of nozzles 20 are arranged at a pitch p in the width direction Y of the recording medium K. The nozzle row 22 as the first nozzle row in the present invention may be configured. In this embodiment, the nozzles 20 of the recording head 2e are black ink, the nozzles 20 of the recording head 2f are cyan ink, and the nozzles 20 of the recording head 2g are magenta ink. The nozzles 20 ... of the recording head 2h are designed to eject yellow ink.

As shown in FIG. 3, the recording heads 4e, 4f include a plurality of head blocks 47,... Arranged in a staggered manner in the width direction Y of the recording medium K.

As shown in FIG. 4, each head block 47 has a plurality of nozzles 40 on the lower surface, and these nozzles 40 have a pitch in the width direction Y of the recording medium K. The nozzle array 42 is configured as a second nozzle array in the present invention. This embodiment , The nozzles 40,... Of the recording head 4e discharge light cyan ink, and the nozzles 40,... Of the recording head 4f discharge light magenta ink. As a result, for yellow and black inks, only the nozzle row 22 that discharges the first droplet amount of liquid droplets is aligned in the transport direction X, so that the second droplet amount droplet is discharged. The number of nozzle rows is reduced and the ink jet recording apparatus 1A is downsized as compared with the case where the nozzle rows to be further arranged are arranged.

[0064] Each nozzle row 42 is aligned with the nozzle row 22 of the recording heads 2e to 2h in the transport direction X !. Further, as shown in FIG. 5, the nozzle row 42 prints an image at a maximum recording rate lower than that of the nozzle row 22. As the maximum recording rate of the nozzle row 42, for example, 50% can be used.

[0065] Next, the operation of the inkjet recording apparatus 1A during image recording will be described.

First, the recording medium K is conveyed in the conveying direction X by the rotation of the conveying rollers 10 and 10.

Next, the recording heads 2e to 2h and the recording heads 4e and 4f discharge ink onto the recording medium K in the region supported by the platen 11. Regarding the hues of cyan and magenta, dots are alternately arranged in the width direction Y and the transport direction X of the recording medium K with respect to the nozzle row 22 of the recording heads 2f and 2g and the nozzle row 42 of the recording heads 4a and 4b. It is preferable to share the formation

[0068] At this time, the first droplet amount discharged from the nozzle row 22 of the recording heads 2e to 2h is larger than the second droplet amount discharged from the nozzle row 42 of the recording heads 4e and 4f. Therefore, in the area of each hue recorded by the nozzle row 22, a dot with a large diameter is formed as compared with the case of recording by the nozzle row 42, and the dot interval is reduced. Further, since the nozzle row 22 records an image at a maximum recording rate higher than that of the nozzle row 42, an area recorded by the nozzle row 22 is compared with a case where an image is recorded at a maximum recording rate of the nozzle row 42 or less. In other words, the area where the dot interval is small becomes wider. On the other hand, since the second droplet amount discharged from the nozzle row 42 is smaller than the first droplet amount discharged from the nozzle row 22, the hues of cyan and magenta recorded by the nozzle row 42 are smaller. In this area, dots having a smaller diameter are recorded as compared with the case where the recording is performed by the nozzle row 22. [0069] The irradiation device 9 is a recording medium downstream of the recording heads 2e to 2h and the recording heads 4e and 4f.

Irradiate light to K. As a result, the ink landed on the recording medium K is cured, and an image is recorded on the surface of the recording medium K.

[0070] Also with the ink jet recording apparatus 1A as described above, the same effects as those of the ink jet recording apparatus 1 can be obtained.

[0071] Note that in this modification, there are two or more forces that are described as arranging only one nozzle row 22 in the transport direction X to eject ink droplets of the first droplet amount. It is good also to install. In this case, by interposing the irradiation device 9 between the nozzle rows 22,.

It is preferable to prevent ink droplets from 22 from being connected to the surface of the recording medium K. Also

In addition, it is preferable that ink droplets are made to land in a complementary manner by offsetting each nozzle row in the width direction Y of the recording medium K by pZ (number of nozzle rows).

Next, a second embodiment of the present invention will be described. The same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[0072] As shown in FIG. 1, the inkjet recording apparatus 1B in the present embodiment includes four recording heads 2i to 2m, four recording heads 3i to 3m, and two recording heads 4i and 4j. X is prepared in the order of leverage.

The recording heads 2 i to 2 m and the recording heads 3 i to 3 m include a plurality of head blocks 28 and 38 arranged in a staggered manner in the width direction Y of the recording medium K.

As shown in FIG. 2, each head block 28, 38 has a plurality of nozzles 23,.

[0075] The plurality of nozzles 23, ... are the first nozzles in the present invention, and ink containing a first content of color material per unit volume with respect to the recording medium K transported by the transport rollers 10, 10. Are discharged as droplets. In this embodiment, the nozzles 23,... Of the recording heads 2i, 3i are black ink, the recording heads ¾, 3j, nozzles 23,... Are cyan ink, and the nozzles 23, 3k of the recording heads 2k, 3k. … Ejects magenta ink, and the nozzles 23,… of the recording head 2m and 3m eject yellow ink.

[0076] In addition, the nozzles 23, ... are arranged at a pitch p in the width direction Y of the recording medium K. The nozzle rows 24 and 34 as the first nozzle row are configured. Among these, each nozzle row 34 of the recording heads 3i to 3m is aligned with the nozzle row 24 of the recording heads 2i to 2m in the transport direction X, and the width direction of the recording medium K with respect to the nozzle row 24 Y is offset by pZ2.

As shown in FIG. 1, the recording heads 4i, 4j include a plurality of head blocks 48,... Arranged in a staggered pattern in the width direction Y of the recording medium K.

As shown in FIG. 2, each head block 48,... Has a plurality of nozzles 43,.

[0079] The plurality of nozzles 43, ... are the second nozzles in the present invention, and have a second content less than the first predetermined amount per unit volume with respect to the recording medium K conveyed by the conveying rollers 10, 10. Ink containing an amount of color material is ejected as droplets. In the present embodiment, the nozzles 43,... Of the recording head 4i eject light cyan ink, and the nozzles 43,... Of the recording head 4j eject light magenta ink.

Further, the nozzles 43,... Are arranged at a pitch p in the width direction Y of the recording medium K, and constitute a nozzle row 44 as the second nozzle row in the present invention.

[0081] Each nozzle row 44 is aligned with the nozzle row 24 of the recording heads 2i to 2m in the transport direction X !. As a result, for cyan and magenta hue inks, the number of nozzle rows 41 arranged in the transport direction X, that is, the number of nozzle rows ejecting ink containing the second content of color material is 1, and the nozzle rows The number of nozzles for ejecting ink containing the first color material is 21, which is 21 and 31. On the other hand, for yellow and black hue inks, only the nozzle rows 24 and 34 that discharge the ink containing the first content of the color material are aligned in the transport direction! Compared to the case where the nozzle rows for discharging the ink containing the material are further arranged, the number of nozzle rows is reduced, and the inkjet recording apparatus 1B is downsized.

[0082] Next, the operation of the inkjet recording apparatus 1B during image recording will be described.

Next, the recording heads 2i to 2m are recorded on the recording medium K in the region supported by the platen 11. Recording heads 3i to 3m and recording heads 4i and 4j eject ink. Regarding the hues of cyan and magenta, the width Y of the recording medium K with respect to the nozzle rows 24 and 34 of the recording heads 3 and 2k and the recording heads 3j and 3k and the nozzle rows 44 of the recording heads 4i and 4j It is preferable to share the dot formation alternately in the transport direction X.

[0085] At this time, the ejection of the nozzle rows 24 and 34 of the recording heads 2i to 2m and the recording heads 3i to 3m is larger than the second content of the color material in the ink ejected from the nozzle rows 44 of the recording heads 4i and 4j. Since the first content of the color material in the ink to be printed is large, darker dots are formed in the area of each hue recorded by the nozzle rows 24 and 34 than in the case of recording by the nozzle row 44. The interval of is visually reduced. In addition, since the nozzle rows 24 and 34 are arranged more in the transport direction than the nozzle rows 44, the area recorded in the nozzle rows 24 and 34, that is, the dot interval, is compared to the case where the same number is arranged. Smaller areas become wider. On the other hand, since the second content of the color material in the ink ejected from the nozzle array 44 is smaller than the first content of the color material in the ink ejected from the nozzle arrays 24 and 34, the recording is performed in the nozzle array 44. In the cyan and magenta hue areas, lighter dots are recorded as compared to the case where the nozzle arrays 24 and 34 are used.

[0086] Further, since the nozzle arrays 24 and 34 are offset by pZ2 in the width direction Y of the recording medium K, in the areas of the respective hues recorded by these nozzle arrays 24 and 34, the spaces between the dots are filled. Complementary ink droplets will land.

Then, the irradiation device 9 irradiates the recording medium K with light on the downstream side of the recording heads 2i to 2m, the recording heads 3i to 3m, and the recording heads 4i and 4j. As a result, the ink landed on the recording medium K is cured, and an image is recorded on the surface of the recording medium K.

At this time, since the irradiation device 9 is interposed between the nozzle rows 24, 34, the ink droplets ejected from the nozzle rows 24,... Are prevented from being connected on the surface of the recording medium K.

[0089] According to the ink jet recording apparatus 1B as described above, since the interval between dots can be visually reduced in each hue region recorded by the nozzle rows 24 and 34, streak-like image defects are eliminated. Occurrence can be prevented. In addition, by arranging the nozzle rows 24 and 34, such a region can be widened, so that it is possible to reliably prevent the occurrence of streak-like image defects. In addition, by offsetting the nozzle rows 24 and 34, ink droplets are complementarily landed. Therefore, the occurrence of streak-like image defects due to variations in the landing positions of the ink droplets can be more reliably prevented.

[0090] In addition, in the cyan and magenta hue areas recorded by the nozzle row 44, thin dots can be recorded, so that the graininess of the image can be reduced. In addition, since the second content of the color material in the ink discharged from the nozzle row 44 is less than the first content of the color material in the ink discharged from the nozzle rows 24 and 34, the image by the nozzle row 41 is reduced. By recording the highlight portion, the graininess of the noble and illite portions can be reliably reduced.

[0091] Further, the irradiation device 9 between the nozzle rows 24 and 34 can prevent ink droplets from these nozzle rows 24 and 34 from being connected on the recording medium K. Even in the case of this type of ink jet recording apparatus, the graininess of the image can be suppressed to a lower level, and the occurrence of streak-like image defects can be more reliably prevented.

Therefore, it is possible to suppress the graininess of the image as compared with the conventional case and to prevent the occurrence of streak-like image defects.

Next, a modification of the second embodiment will be described. The same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

As shown in FIG. 3, the ink jet recording apparatus 1C according to the present modification includes four recording heads 2n to 2r and two recording heads 4n and 4p in this order in the transport direction X.

The recording heads 2n to 2r include a plurality of head blocks 29,... Arranged in a staggered manner in the width direction Y of the recording medium K. As shown in FIG. 4, each head block 29 has a plurality of nozzles 23 on the lower surface, and the plurality of nozzles 23 are arranged at a pitch p in the width direction Y of the recording medium K. The nozzle row 25 as the first nozzle row in the present invention may be configured. In this embodiment, the nozzles 23 of the recording head 2n are black ink, the nozzle 23 of the recording head 2p is cyan ink, and the nozzle 23 of the recording head 2q is magenta ink. The nozzles 23, ... of the recording head 2r are designed to eject yellow ink.

The recording heads 4n, 4p are provided with a plurality of head blocks 49,... Arranged in a staggered manner in the width direction Y of the recording medium K, as shown in FIG. As shown in FIG. 4, each head block 49, has a plurality of nozzles 43,... On the lower surface, and the plurality of nozzles 43,... Are pitched in the width direction Y of the recording medium K. The nozzle rows 45 are arranged as p, and serve as the second nozzle row in the present invention. In this embodiment, the nozzles 43,... Of the recording head 4n discharge light cyan ink as cyan hue ink, and the nozzle 43,... Of the recording head 4p discharges light magenta ink as magenta hue ink. It is supposed to be. As a result, for the yellow and black hue inks, only the nozzle row 25 that discharges the ink containing the first content of the color material is aligned in the transport direction, so the second content of the color material is contained. Compared to a case where nozzle rows for ejecting ink are further arranged, the number of nozzle rows is reduced, and the inkjet recording apparatus 1C is downsized.

Each nozzle row 45 is aligned with the nozzle row 25 of the recording heads 2n to 2r in the transport direction X! Further, as shown in FIG. 5, the nozzle array 45 records an image at a maximum recording rate lower than that of the nozzle array 25. As the maximum recording rate of the nozzle row 45, for example, 50% can be used.

[0098] Next, the operation of the inkjet recording apparatus 1C during image recording will be described.

[0100] Next, the recording heads 2n to 2r and the recording heads 4η and 4ρ eject ink onto the recording medium K in the region supported by the platen 11. Regarding the hues of cyan and magenta, the nozzle array 25 of the recording heads 2p and 2q and the nozzle array 45 of the recording heads 4n and 4p are alternately arranged in the width direction Y and the transport direction X of the recording medium K. It is preferable to share dot formation

[0101] At this time, the second content of the color material in the ink discharged from the nozzle array 45 of the recording heads 4n and 4p is larger than the second content of the color material in the ink discharged from the nozzle array 25 of the recording heads 2n to 2r. 1 Since the content is large, in the area of each hue recorded by the nozzle row 25, darker dots are formed compared to the case of recording by the nozzle row 45, and the dot interval is visually reduced. The nozzle row 25 is higher than the nozzle row 45 and records an image at the maximum recording rate. Therefore, the nozzle row 25 is recorded by the nozzle row 25 as compared with the case of recording an image at the maximum recording rate of the nozzle row 45 or less. Area That is, the region where the dot interval is small becomes wide. On the other hand, since the second content in the ink discharged from the nozzle row 45 is less than the first content of the color material in the ink discharged from the nozzle row 25, the hues of cyan and magenta recorded by the nozzle row 45 are reduced. In this area, thin dots are recorded as compared with the case where the nozzle array 25 records.

Then, the irradiation device 9 irradiates the recording medium K with light on the downstream side of the recording heads 2n to 2r and the recording heads 4n and 4p. As a result, the ink landed on the recording medium K is cured, and an image is recorded on the surface of the recording medium K.

[0103] Also with the ink jet recording apparatus 1C as described above, the same effects as those of the ink jet recording apparatus 1B can be obtained.

[0104] In the present modification, it has been described that only one nozzle row 25 that discharges the ink containing the color material having the first content is arranged in the transport direction X. It may be arranged as described above. In this case, it is preferable to prevent the ink droplets from the nozzle row 25 from being connected to the surface of the recording medium K by interposing the irradiation device 9 between the nozzle rows 25,. In addition, it is preferable that the ink droplets are complementarily landed by offsetting each nozzle row by pZ (the number of nozzle rows) in the width direction Y of the recording medium K.

In the above-described embodiment, the recording heads 2a to 2d and the like include the head blocks 26 and the like arranged linearly as described in the description that the recording heads 2a to 2d and the like include the head blocks 26 and the like arranged in a staggered manner It's also good. An irradiation device may be provided between the recording heads 2n, 2p, 2q, 2r.

Claims

The scope of the claims

[1] a transport device for transporting the recording medium in the transport direction;

The inkjet recording apparatus, wherein the number of the first nozzle rows arranged in the carrying direction is larger than the number of the second nozzle rows arranged in the carrying direction.

[2] a transport device for transporting the recording medium in the transport direction;

An inkjet recording apparatus, wherein a maximum recording rate of the first nozzle row is higher than that of the second nozzle row.

[3] In the ink jet recording apparatus according to claim 1 or 2,

The first content of the color material per unit volume of ink discharged from the first nozzle row cover is more than the second content of the color material per unit volume of ink discharged from the second nozzle row cover. An ink jet recording apparatus characterized by that.

[4] a transport device for transporting the recording medium in the transport direction; A plurality of first nozzle forces configured to eject a predetermined hue of ink containing a first content of color material per unit volume as droplets onto a recording medium conveyed by the conveying device. A nozzle row;

[5] a transport device for transporting the recording medium in the transport direction;

[6] In the ink jet recording apparatus according to any one of claims 1 to 5, the plurality of first nozzles include:

Among these n first nozzle rows, (n−l) first nozzle rows are offset by pZn in the intersecting direction with respect to the remaining one first nozzle row. Inkji Recording device.

[7] The ink jet recording apparatus according to any one of claims 1 to 6, wherein photocurable ink is ejected from the first nozzle row and the second nozzle row. An ink jet recording apparatus, wherein a light irradiation device is provided in a region where the ink lands on the recording medium.

[8] In the ink jet recording apparatus according to claim 7,

An ink jet recording apparatus, comprising: a light irradiating device provided in a region interposed between a plurality of first nozzle arrays and where ink ejected from the first nozzle arrays lands on a recording medium.

[9] The ink jet recording apparatus according to any one of claims 1 to 8, wherein the first nozzle array and the second nozzle array that discharge cyan ink are used, and magenta. The first nozzle row and the second nozzle row for ejecting ink of a hue of the color; the first nozzle row for ejecting ink of a yellow hue;

An ink jet recording apparatus comprising: the first nozzle row that ejects black hue ink.

[10] In the ink jet recording apparatus according to claim 9,

An ink jet recording apparatus comprising: a light irradiation device provided in a region where the ink ejected from the first nozzle row lands on a recording medium, interposed between nozzle rows ejecting inks of different hues .