JP4178559B2 - Inkjet recording method and apparatus - Google Patents

Description

  The present invention relates to an ink jet recording method and apparatus, and more particularly to an ink jet recording method and apparatus suitable for suppressing bleeding.

  Various ink jet recording methods have been proposed. For example, in the bubble (thermal) method, the ink is heated and foamed, and the ink is ejected using the pressure. In the piezoelectric method or the sound wave method, the ink is ejected by applying mechanical vibration or displacement to the ink using a piezoelectric element or a sound wave generating element. In addition, a method of ejecting ink from a nozzle using a magnetic field or an electric field has been proposed. In such an ink jet recording method, recording is performed by causing a small drop of ink to fly and adhering a part or all of it to a recording medium such as paper, so that no noise is generated and high speed recording and multicolor recording are possible. It is.

  Usually, inks used for ink jet recording are mainly composed of a coloring material such as a dye or pigment as a recording agent and a liquid medium. As the recording agent, a water-soluble dye, preferably an acid dye or a direct dye, is used from the viewpoints of safety, recording characteristics, and the like. On the other hand, a liquid medium mainly containing water is used from the viewpoints of safety and recording characteristics. In consideration of clogging of the head nozzle and ejection stability, polyhydric alcohol or the like is often added to the liquid medium.

  As a recording medium used in the ink jet recording method, ordinary paper such as high-quality paper for copying, paper referred to as ink jet recording paper, or the like is used. An inkjet recording paper is a paper in which an ink-absorbing and / or ink-soluble ink receiving layer is provided on a substrate. However, with the improvement of the performance of the ink jet recording apparatus such as higher recording speed and multi-color recording, the fixing of the ink to the recording medium is performed stably and promptly, and the ink bleed is not noticeable. Has become particularly demanding for regular paper.

  When bleeding (hereinafter referred to as bleed) occurs when inks of different colors are mixed at the boundary between the two colors, the recording quality deteriorates. Therefore, conventionally, various methods have been proposed as a method for suppressing bleed. For example, the following methods (1) to (7) have been proposed.

  Method (1) increases the interfacial tension between the two colors of ink that form the color boundary, and is proposed in, for example, Japanese Patent Application Laid-Open No. 2-175253. Method (2) is to vary the permeability of each ink into the recording medium, and is proposed in, for example, Japanese Patent Application Laid-Open Nos. 4-355157 and 4-364961. The method (3) does not attach ink to the boundary portion of the color and makes it so-called white, and is proposed in, for example, Japanese Patent Laid-Open No. 3-146355.

  Method (4) completes recording by performing thinning recording a plurality of times, and is proposed in, for example, Japanese Patent Laid-Open No. 3-146355. In the method (5), an ink agent is coated on the recording medium in advance to prevent the ink from penetrating and spreading into the recording medium so that the ink does not contact at the boundary of the color. This is proposed in Japanese Laid-Open Patent Application No. 3-002046. Method (6) is to reduce the number and amount of ink particles to be recorded in the color boundary portion. Method (7) uses a fixing device for forcibly evaporating the ink adhering to the recording medium.

  However, in the above method (1) or (2), since the permeability of the ink to the recording medium is different, when recording with a highly permeable ink, bleeding along the paper fiber at the edge of the recording portion occurs. There is a problem that the image becomes large, the sharpness is lost, and the image quality is greatly deteriorated.

  In the above method (3), since a white unrecorded portion is formed at the color boundary portion, there is a problem that the image and the recording density of the entire image are lowered. In particular, there is a problem that image quality is significantly deteriorated at a color boundary portion with a dark color having a large contrast with white.

  The method (4) has a problem in that the recording speed decreases because the number of scans of the recording medium of the head for recording increases. In the above method (5), since the size of the dots formed by the ink is reduced, there is a problem that the recording density is lowered or the dots are uneven and the image quality is deteriorated. In addition, the user has to use a dedicated recording medium, which is inconvenient.

  The method (6) has a problem in that the image quality deteriorates due to a decrease in resolution or a decrease in recording density at the boundary between colors. The method (7) has a problem that it is necessary to provide a relatively large fixing device, and the ink jet recording apparatus is increased in size and power consumption is increased.

  By the way, in order to record a line image or a general image on a recording medium at a desired resolution in an inkjet recording apparatus, it is necessary to adjust the amount of ink ejected from the head so that dots having a size suitable for the desired resolution can be obtained. is there. Since the ink having low penetrability has a smaller dot spread on the recording medium than the ink having high penetrability, a larger amount of ink is recorded on the recording medium than the ink having high penetrability. This tendency is prominent in plain paper such as copy paper, bond paper, and postcards that have been subjected to processing such as a size that suppresses ink permeation as a recording medium. In contrast, ink-jet recording paper such as coated paper for exclusive use of ink-jet recording, overhead projector (OHP) film, and glossy paper has an ink receiving layer on the paper / film substrate, so that ink permeation is uniform. In addition, the ink penetration effect is relatively small because it is designed to speed up. The ink receiving layer is made of, for example, a hydrophilic / water-absorbing polymer such as polyvinyl alcohol or cationic resin, a resin, a pigment, a binder, or the like.

  As described above, since inks having different penetrability have greatly different properties on the recording medium, there is a problem that it is difficult to design a recording medium satisfying sufficient performance for each ink. Further, since the diameter of the nozzle of the head is as small as 50 μm to 100 μm, for example, a non-volatile and highly hygroscopic solvent (so that it does not clog due to evaporation and drying of ink at the nozzle tip (nozzle orifice)) ( Solvent) is added to the ink. However, even if clogging due to the folding of the dye in the nozzle orifice can be prevented, thickening of the ink due to evaporation of the solvent is inevitable. As the ink viscosity increases, the ink ejection direction becomes undefined, causing a positional deviation of dots recorded on the recording medium, and in an extreme case, the ink cannot be ejected, resulting in missing dots. Therefore, a method has been proposed in which ink is ejected (sprayed) from the nozzle to the backup unit so that the viscosity of the ink does not exceed a certain level. However, the degree of thickening of the ink differs depending on the type and concentration of the wetting agent or dye contained in the ink, and may be different among many types of ink used in the same inkjet recording apparatus. In the past, no consideration was given to the degree of thickening that differs between inks.

  Accordingly, an object of the present invention is to provide an ink jet recording method and apparatus, an ink, and an ink cartridge capable of performing high quality recording. More specifically, the present invention suppresses bleeding at the color boundary portion so that the recording density, brightness, and saturation are not different in the recording portion of the same hue, and / or characters are printed. It is a first object of the present invention to provide an ink jet recording method and apparatus, an ink and an ink cartridge capable of preventing bleeding from occurring.

  It is a second object of the present invention to provide an ink jet recording method and apparatus that enable high-quality recording without uneven recording density even when inks having different permeability are used. Furthermore, a third object of the present invention is to provide an ink jet recording method and apparatus that can realize high-quality recording with high reliability by stabilizing ink ejection that is influenced by ink thickening.

The third problem is that in the ink jet recording method for recording a color image on a recording medium using ink of at least two or more hues according to claim 1, there is a difference in increase in ink viscosity due to solvent evaporation of each ink. When each ink is left open at room temperature and humidity of 25 ° C. and 60% RH for 5 days so that V / S = 10 mm is satisfied when the volume of the ink to be released is Vmm ³ and the open area is Smm ² Can also be achieved by an inkjet recording method set to be within 1000 cp.

According to a second aspect of the present invention, in the first aspect of the invention, a color image is recorded on the recording medium using the inks of the two or more hues by a head portion composed of heads having different numbers of nozzles, and according to the number of nozzles. Adjust the degree of thickening of each ink.

According to a third aspect of the present invention, in the second aspect of the invention, when the number of nozzles of the first head of the head portion is m and the number of nozzles of the second head is n, the ink supplied to the first head The degree of thickening is set to n / m times the degree of thickening of the ink supplied to the second head.

The third problem is that in the ink jet recording apparatus for recording a color image on a recording medium using ink of at least two or more hues according to claim 4, there is a difference in increase in ink viscosity due to solvent evaporation of each ink. When each ink is left open at room temperature and humidity of 25 ° C. and 60% RH for 5 days so that V / S = 10 mm is satisfied when the volume of the ink to be released is Vmm ³ and the open area is Smm ² Can also be achieved by an ink jet recording apparatus set to be within 1000 cp.

According to a fifth aspect of the invention, in the fourth aspect of the invention, there is provided means for recording a color image on the recording medium using the inks of the two or more hues by a head portion comprising heads having different numbers of nozzles. The degree of thickening of each ink is adjusted according to the number.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, when the number of nozzles of the first head of the head unit is m and the number of nozzles of the second head is n, the ink supplied to the first head The degree of thickening is set to n / m times the degree of thickening of the ink supplied to the second head.

According to the first aspect of the present invention, it is possible to improve the recording speed and to reduce the ink consumption by minimizing the spraying condition of the head for preventing the ink thickening that causes dot dropout and dot deviation. Can be reduced.

According to the second and third aspects of the invention, the ink thickening is adjusted according to the frequency of use of the head, so that the spraying condition of the head can be suppressed to the minimum regardless of the number of heads. According to the fourth aspect of the present invention, the recording speed is improved and the ink consumption is reduced by minimizing the spray conditions of the head for preventing ink thickening that causes dot omission and dot deviation. Can be reduced.

According to the fifth and sixth aspects of the invention, the ink thickening is adjusted according to the frequency of use of the head, so that the spraying condition of the head can be suppressed to the minimum regardless of the number of heads.

  The present invention can also be specified as follows.

  (Appendix 1) In an ink jet recording method for recording an image by attaching a plurality of hue inks to a recording medium, for at least one predetermined hue, two types of inks having different permeability to the recording medium are used. Among the inks, the ink having low penetrability includes the predetermined hues on the recording medium using the inks having a plurality of hues that have lower penetrability than inks having hues other than the predetermined hue. In the boundary portion between the first recording area and the second recording area having a hue different from the predetermined hue and adjacent to the first recording area, the ink having the higher permeability of the two types of inks. In the inkjet recording method, recording is performed over at least a predetermined recording width up to the second recording area, and the remaining portion of the boundary portion is recorded with the ink having the lower permeability of the two types.

  (Additional remark 2) The inkjet recording method of Additional remark 1 whose brightness of the said predetermined hue is lower than the brightness of another hue.

  (Supplementary note 3) The ink according to Supplementary note 1 or 2, wherein the ink having higher permeability in the predetermined hue and the ink of other hue having the same high permeability have higher permeability as the lightness of the hue is lower. Recording method.

  (Appendix 4) The inkjet recording method according to any one of appendices 1 to 3, wherein the predetermined hue is black.

  (Supplementary note 5) The inkjet recording method according to supplementary note 4, wherein the other hues are yellow, magenta, and cyan, respectively.

  (Supplementary note 6) The inkjet recording method according to any one of supplementary notes 1 to 5, wherein the ink having a hue with low lightness is recorded first.

  (Supplementary note 7) The remaining portion of the first recording area and the boundary portion is recorded with the ink having the lower permeability and the predetermined hue, and then the second recording area is printed with a hue other than the predetermined hue. 6. The ink jet recording method according to any one of appendices 1 to 5, wherein recording is performed with ink, and then the portion having the predetermined recording width is sequentially recorded with ink having the predetermined hue and higher permeability.

  (Supplementary Note 8) When the remaining portion of the boundary portion is larger than the predetermined recording width portion, the recording with the ink having the higher permeability in the predetermined hue is performed with the lower permeability in the predetermined hue. The inkjet recording method according to any one of appendices 1 to 5, which is performed prior to recording with ink.

  (Supplementary Note 9) When the remaining portion of the boundary portion is larger than the predetermined recording width portion, the recording with the ink having the lower permeability in the predetermined hue is performed with the higher permeability in the predetermined hue. The inkjet recording method according to any one of appendices 1 to 5, which is performed prior to recording with ink.

  (Supplementary Note 10) When the remaining portion of the boundary portion is smaller than the portion of the predetermined recording width, the recording with the ink having the lower permeability in the predetermined hue is performed with the one having the higher permeability in the predetermined hue. The inkjet recording method according to any one of appendices 1 to 5, which is performed prior to recording with ink.

  (Additional remark 11) The remaining part of the first recording area and the boundary part is recorded with the ink having a lower permeability with the predetermined hue, and after the predetermined time, the part with the predetermined recording width is recorded with the predetermined hue. The recording is performed with the ink having the higher penetrability, and the predetermined time is set to be longer than the familiar time of the ink having the lower permeability with the predetermined hue with respect to the recording medium. The inkjet recording method as described.

  (Supplementary note 12) The inkjet according to any one of supplementary notes 1 to 5, wherein the predetermined recording width is adjusted based on at least one of an amount of ink for recording the boundary portion and a permeability of the ink. Recording method.

  (Supplementary note 13) The inkjet recording method according to any one of supplementary notes 1 to 5, wherein at least one of the first and second regions is overprinted with ink of two or more hues.

  (Supplementary note 14) The inkjet recording method according to any one of supplementary notes 1 to 5, wherein, in the boundary portion, the portion of the predetermined recording width and the remaining portion have substantially the same brightness and / or saturation.

  (Supplementary note 15) The inkjet recording method according to supplementary note 14, wherein a color difference between the predetermined recording width portion and the remaining portion is 5 or less at the boundary portion.

  (Supplementary note 16) The ink according to any one of supplementary notes 1 to 5, wherein the ink having higher permeability in the predetermined hue and the ink having lower permeability in the predetermined hue each use the same dye. Inkjet recording method.

  (Supplementary note 17) The inkjet recording method according to any one of supplementary notes 1 to 5, wherein in the boundary portion, the portion having the predetermined recording width and the remaining portion have substantially the same recording density.

  (Supplementary note 18) The inkjet recording method according to any one of supplementary notes 1 to 5, wherein, in the boundary portion, a difference in recording density between the predetermined recording width portion and the remaining portion is 0.3 or less.

  (Supplementary note 19) The ink jet recording method according to supplementary note 18, wherein the amount of dye contained in the ink having higher permeability in the predetermined hue is greater than the amount of dye contained in the ink having lower permeability in the predetermined hue.

  (Supplementary Note 20) The amount of ink that adheres to the lower area of the predetermined hue in the remaining portion of the boundary portion per unit area is determined by the ink having the higher permeability in the predetermined hue. The ink jet recording method according to appendix 18, wherein the ink amount is larger than the amount of ink deposited per unit area within a predetermined recording width portion of the boundary portion.

  (Supplementary Note 21) In an inkjet recording apparatus that records an image by attaching a plurality of hue inks to a recording medium, at least one predetermined hue uses two types of inks having different permeability to the recording medium. A head section having a number of heads corresponding to the type of the recording medium, a first recording area including the predetermined hue on the recording medium, and a hue different from the predetermined hue and adjacent to the first recording area In the boundary portion with the second recording area, recording is performed over at least a predetermined recording width up to the second recording area with the ink having the higher permeability of the two types of ink, and the remaining portion of the boundary portion is recorded. An ink jet recording apparatus comprising a control unit for controlling the head unit so that the recording is performed with the ink having the lower permeability of the two types.

  (Additional remark 22) The said head part is an inkjet recording device of Additional remark 21 using the ink whose brightness of the said predetermined hue is lower than the lightness of another hue.

  (Additional remark 23) The ink with the higher permeability of the predetermined hue used by the head unit and the ink of the other hue having the same high permeability have higher permeability as the lightness of the hue is lower. Or the inkjet recording device of 22.

  (Supplementary Note 24) The inkjet recording apparatus according to any one of Supplementary Notes 21 to 23, wherein the predetermined hue of the ink used by the head unit is black.

  (Supplementary note 25) The inkjet recording apparatus according to supplementary note 24, wherein the other hues of the ink used by the head unit are yellow, magenta, and cyan, respectively.

  (Supplementary note 26) The ink jet recording apparatus according to any one of supplementary notes 21 to 25, wherein the control unit controls the head unit so that ink of a hue having low lightness is recorded first.

  (Supplementary Note 27) The control means records the first recording area and the remaining part of the boundary portion with the ink having a lower permeability and the predetermined hue, and then the second recording area is recorded on the predetermined recording area. Any one of appendices 21 to 25, wherein the head unit is controlled to record with ink having a hue other than the hue, and then sequentially record the portion of the predetermined recording width with the ink having the higher permeability and the predetermined hue. An ink jet recording apparatus according to claim 1.

  (Supplementary Note 28) When the remaining portion of the boundary portion is larger than the portion of the predetermined recording width, the control means performs recording with ink having a higher permeability in the predetermined hue with the predetermined hue. 26. The ink jet recording apparatus according to any one of appendices 21 to 25, wherein the head unit is controlled to be performed prior to recording with an ink having a lower permeability.

  (Supplementary Note 29) When the remaining portion of the boundary portion is smaller than the predetermined recording width portion, the control means performs recording with the ink having a lower permeability in the predetermined hue with the predetermined hue. 26. The ink jet recording apparatus according to any one of appendices 21 to 25, wherein the head unit is controlled so as to be performed prior to recording with ink having a higher permeability.

  (Supplementary Note 30) When the remaining portion of the boundary portion is larger than the portion of the predetermined recording width, the control means performs recording with the ink having a lower permeability in the predetermined hue with the predetermined hue. 26. The ink jet recording apparatus according to any one of appendices 21 to 25, wherein the head unit is controlled so as to be performed prior to recording with ink having a higher permeability.

  (Additional remark 30) The said control means records the remaining part of the said 1st recording area and a boundary part with the ink of the low permeability | transmittance with the said predetermined hue, and the part of the said predetermined recording width is after the predetermined time. The head unit is controlled to record with the ink having the higher permeability with the predetermined hue, and the predetermined time is set longer than the familiarity time of the ink with the lower permeability with the predetermined hue with respect to the recording medium. 26. The inkjet recording apparatus according to any one of supplementary notes 21 to 25.

  (Appendix 31) The inkjet according to any one of appendices 21 to 25, wherein the predetermined recording width is adjusted based on at least one of an amount of ink for recording the boundary portion and a permeability of the ink. Recording device.

  (Additional remark 32) The said control means controls the said head part so that at least one of the said 1st and 2nd area | regions may be overlap-recorded with the ink of two or more hues, Any of Additional remarks 21-25 An ink jet recording apparatus according to claim 1.

  (Supplementary note 33) The ink jet recording apparatus according to any one of supplementary notes 21 to 25, wherein in the boundary portion, the portion of the predetermined recording width and the remaining portion have substantially the same brightness or saturation.

  (Supplementary note 34) The inkjet recording apparatus according to supplementary note 33, wherein a color difference between the portion having the predetermined recording width and the remaining portion is 5 or less at the boundary portion.

  (Appendix 35) Of the appendices 21 to 25, the same dye used for the ink having higher penetrability in the predetermined hue and the ink having lower penetrability in the predetermined hue are used. An ink jet recording apparatus according to any one of the preceding claims.

  (Supplementary note 36) The inkjet recording apparatus according to any one of supplementary notes 21 to 25, wherein the predetermined recording width portion and the remaining portion have substantially the same recording density at the boundary portion.

  (Supplementary note 37) The inkjet recording apparatus according to any one of supplementary notes 21 to 25, wherein, in the boundary portion, a difference in recording density between the predetermined recording width portion and the remaining portion is 0.3 or less.

  (Appendix 38) The amount of dye contained in the ink having higher permeability in the predetermined hue used by the head unit is greater than the amount of dye contained in the ink having lower permeability in the predetermined hue. Inkjet recording device.

  (Supplementary Note 39) The control means is configured such that the amount of ink to which the ink having lower permeability in the predetermined hue adheres per unit area in the remaining portion of the boundary portion is higher in permeability in the predetermined hue. 40. The ink jet recording apparatus according to appendix 37, wherein the head portion is controlled so that the amount of ink is larger than the amount of ink deposited per unit area within a predetermined recording width portion of the boundary portion.

  (Additional remark 40) The said control means has a high permeability | transmittance by this predetermined hue with the amount of ink which the ink with the lower permeability of the said predetermined hue adheres per unit area in the said remaining part of the said boundary part. 39. The ink jet recording apparatus according to appendix 38, wherein the head portion is controlled so that the amount of ink is larger than the amount of ink adhering per unit area within a predetermined recording width portion of the boundary portion.

  (Supplementary note 41) An ink cartridge for storing ink of a predetermined hue used together with a plurality of hues of ink when performing ink jet recording on a recording medium, the cartridge main body, and the cartridge main body stored in the cartridge main body The ink of a predetermined hue, the ink of the predetermined hue has a lower permeability than the ink of the plurality of hues, and has a lightness lower than that of the ink of the plurality of hues. ink cartridge.

  (Supplementary note 42) The ink cartridge according to supplementary note 41, wherein the ink of the predetermined hue is black ink.

  (Supplementary note 43) The ink cartridge according to supplementary note 41 or 42, wherein the ink of the predetermined hue uses the same dye as the inks of the plurality of hues.

  (Supplementary Note 44) The ink cartridge according to any one of Supplementary Notes 41 to 43, wherein a dye amount included in the ink of the predetermined hue is greater than a dye amount included in the plurality of hue inks.

  (Supplementary Note 45) An ink cartridge for storing ink of a predetermined hue that is used together with black ink when performing ink jet recording on a recording medium, the cartridge main body, and a predetermined cartridge stored in the cartridge main body An ink cartridge comprising ink of a hue, the ink of the predetermined hue having higher permeability than the black ink and having a lightness higher than that of the black ink.

  (Supplementary note 46) The ink cartridge according to supplementary note 45, wherein the ink of the predetermined hue is an ink of one hue selected from black, yellow, magenta, and cyan.

  (Supplementary note 47) The ink cartridge according to supplementary note 46, wherein the ink of the predetermined hue has higher permeability as the lightness is lower.

  (Supplementary note 48) The ink cartridge according to supplementary note 45, wherein the ink of the predetermined hue is black ink using the same dye as the black ink.

  (Appendix 49) The ink cartridge according to any one of appendices 45 to 48, wherein a dye amount included in the ink of the predetermined hue is larger than a dye amount included in the black ink.

  (Supplementary Note 50) An ink cartridge for storing ink of a predetermined hue that is used together with a plurality of hues of ink when performing ink jet recording on a recording medium, the cartridge main body, and the cartridge main body being stored in the cartridge main body The ink of a predetermined hue is different from the Rf value of the color material movement rate, and the ink of a hue with a higher brightness than the Rf value of the plurality of hues of ink. An ink cartridge having a low Rf value.

  (Supplementary note 51) The ink cartridge according to supplementary note 50, wherein the ink having the predetermined hue uses a dye having a different Rf value according to the lightness thereof.

  (Supplementary Note 52) An ink cartridge for storing ink of a predetermined hue that is used together with a plurality of hues of ink when performing ink jet recording on a recording medium, the cartridge main body, and the cartridge main body stored in the cartridge main body An ink cartridge comprising an ink of a predetermined hue, and a contact angle of the ink of the predetermined hue with respect to the recording medium is 85 ° or more or 70 ° or less.

  (Supplementary note 53) The ink cartridge according to supplementary note 52, wherein the ink having the predetermined hue is black ink.

  (Supplementary note 54) An ink cartridge for storing ink of a predetermined hue used together with a plurality of hues of ink when performing ink jet recording on a recording medium, the cartridge main body, and the cartridge main body stored in the cartridge main body An ink cartridge comprising an ink having a predetermined hue, wherein the surface tension of the ink having the predetermined hue with respect to the recording medium is not less than 49 dyne / cm or not more than 45 dyne / cm.

  (Supplementary note 55) The ink cartridge according to supplementary note 52, wherein the ink of the predetermined hue is black ink.

(Supplementary Note 56) An ink cartridge for storing ink of a predetermined hue that is used together with a plurality of hue inks when performing ink jet recording on a recording medium, the cartridge main body, and the cartridge main body stored in the cartridge main body An ink cartridge comprising an ink of a predetermined hue, wherein an absorption coefficient Ka (nl / (mm ² · s ^1/2 )) of the ink of the predetermined hue with respect to the recording medium is set to be less than 15.

  (Supplementary note 57) The ink cartridge according to supplementary note 56, wherein the ink of the predetermined hue is black ink.

(Supplementary note 58) An ink cartridge for storing ink of a predetermined hue that is used together with black ink when performing ink jet recording on a recording medium, the cartridge main body, and a predetermined cartridge stored in the cartridge main body An ink cartridge comprising an ink of a hue, wherein an absorption coefficient Ka (nl / (mm ² · s ^1/2 )) of the ink of the predetermined hue with respect to the recording medium is set to 40 or more.

  (Supplementary note 59) The ink cartridge according to supplementary note 58, wherein the ink having the predetermined hue is one of black, yellow, magenta, and cyan.

  (Supplementary Note 60) An ink having a predetermined hue that is used together with black ink when ink jet recording is performed on a recording medium, and the ink having the predetermined hue is less than the black ink for the recording medium. An ink having high penetrability and lightness higher than that of the black ink.

  (Supplementary note 61) The ink according to supplementary note 60, wherein the predetermined hue is one hue selected from black, yellow, magenta, and cyan.

  (Supplementary note 62) The ink according to supplementary note 61, wherein the ink having the predetermined hue has higher permeability as the lightness is lower.

  (Supplementary note 63) The ink according to supplementary note 60, wherein the ink of the predetermined hue is a black ink using the same dye as the black ink.

  (Supplementary note 64) The ink according to any one of supplementary notes 60 to 63, wherein a dye amount included in the ink of the predetermined hue is larger than a dye amount included in the black ink.

  (Supplementary Note 65) An ink having a predetermined hue that is used together with a plurality of hue inks when performing ink jet recording on a recording medium, and the ink having the predetermined hue is an Rf value that is a movement rate of a color material Is different from the Rf value of the plurality of hue inks, and the Rf value is set lower than that of the ink of the hue hue higher than the brightness.

  (Supplementary Note 66) The ink according to supplementary note 65, wherein the ink having the predetermined hue uses a dye having a different Rf value according to its lightness.

  (Supplementary note 67) Ink of a predetermined hue used together with a plurality of hue inks when performing ink jet recording on a recording medium, and a contact angle of the ink of the predetermined hue with respect to the recording medium is 85 ° or more Ink that is 70 ° or less.

  (Supplementary note 68) The ink according to supplementary note 67, wherein the predetermined hue is black.

  (Appendix 69) An ink having a predetermined hue that is used together with a plurality of hue inks when performing ink jet recording on a recording medium, and the surface tension of the ink of the predetermined hue with respect to the recording medium is 49 dyne / cm Ink that is above or below 45 dyne / cm.

  (Supplementary note 70) The ink according to supplementary note 69, wherein the predetermined hue is black.

(Supplementary Note 71) An ink having a predetermined hue that is used together with a plurality of hue inks when performing ink jet recording on a recording medium, and the absorption coefficient Ka (nl / (Mm ² · s ^1/2 )) is set to less than 15, ink.

  (Supplementary note 72) The ink according to supplementary note 71, wherein the predetermined hue is black.

(Supplementary Note 73) An ink having a predetermined hue that is used together with black ink when ink jet recording is performed on a recording medium, and an absorption coefficient Ka (nl / (mm) of the ink of the predetermined hue with respect to the recording medium. ² · s ^1/2 )) is set to 40 or more.

  (Supplementary note 74) The ink according to supplementary note 73, wherein the predetermined hue is one of black, yellow, magenta, and cyan.

  In the inkjet recording method for recording an image by attaching a plurality of hues of ink to a recording medium, the first problem described above is that at least one predetermined hue has a permeability to the recording medium. Two different types of inks are used, and among the inks, the ink having a low penetrability uses the inks having a plurality of hues that are less penetrable than the inks having a hue other than the predetermined hue. In the boundary portion between the first recording area including the predetermined hue and the second recording area adjacent to the first recording area and having a hue different from the predetermined hue, the two types of ink Recording is performed over at least a predetermined recording width up to the second recording area with the ink having the higher permeability, and the remaining portion of the boundary portion is changed to ink having a hue other than the predetermined hue among the two types. Even penetration It can be achieved by an ink jet recording method for recording at the lower ink of.

  In the invention according to appendix 2, in the invention according to appendix 1, the brightness of the predetermined hue is lower than the brightness of other hues. In the invention according to appendix 3, in the invention according to appendix 1 or 2, the ink having higher permeability in the predetermined hue and the ink of other hue having the same high permeability have higher penetration as the lightness of the hue is lower. Have sex.

  In the invention according to supplementary note 4, in any one of the supplementary notes 1 to 3, the predetermined hue is black. In the invention according to appendix 5, in the invention according to appendix 4, the other hues are yellow, magenta and cyan, respectively.

  In the invention described in appendix 6, in any one of appendices 1 to 5, ink having a hue with low brightness is recorded first. In the invention according to appendix 7, in any one of the appendices 1 to 5, the remaining portion of the first recording area and the boundary portion is recorded with the ink having a lower permeability with the predetermined hue, Thereafter, the second recording area is recorded with ink having a hue other than the predetermined hue, and then the portion with the predetermined recording width is sequentially recorded with the ink having higher permeability with the predetermined hue.

  In the invention according to appendix 8, in any one of appendices 1 to 5, in the case where the remaining portion of the boundary portion is larger than the portion of the predetermined recording width, the one having higher permeability with the predetermined hue The recording with the ink is performed before the recording with the ink having the lower permeability with the predetermined hue.

  In the invention according to appendix 9, in any one of appendices 1 to 5, when the remaining portion of the boundary portion is larger than the portion of the predetermined recording width, the one having the predetermined hue and low permeability The recording with the ink is performed before the recording with the ink having the higher permeability at the predetermined hue.

  In the invention according to appendix 10, in any one of appendices 1 to 5, in the case where the remaining portion of the boundary portion is smaller than the portion of the predetermined recording width, the one having low permeability with the predetermined hue The recording with the ink is performed before the recording with the ink having the higher permeability at the predetermined hue.

  In the invention according to appendix 11, in any one of the appendices 1 to 5, the remaining portion of the first recording area and the boundary portion is recorded with the ink having a lower permeability with the predetermined hue, After the predetermined time, the portion having the predetermined recording width is recorded with the ink having the higher permeability in the predetermined hue, and the predetermined time is the familiarity time of the ink having the lower permeability with the predetermined hue with respect to the recording medium. It is set longer.

  In the invention according to appendix 12, in any one of appendices 1 to 5, the predetermined recording width is adjusted based on at least one of an amount of ink that records the boundary portion and a permeability of the ink. Is done. In the invention according to appendix 13, in any one of appendices 1 to 5, at least one of the first and second areas is overprinted with inks of two or more hues.

  In the invention according to appendix 14, in any one of appendices 1 to 5, in the boundary portion, the predetermined recording width portion and the remaining portion have substantially the same brightness and / or saturation. In the invention according to appendix 15, in the invention according to appendix 14, the color difference between the predetermined recording width portion and the remaining portion in the boundary portion is 5 or less.

  In the invention according to appendix 16, in any one of the appendices 1 to 5, the ink having higher permeability in the predetermined hue and the ink having lower permeability in the predetermined hue are the same. Use dyes. In the invention according to appendix 17, in any one of appendices 1 to 5, in the boundary portion, the predetermined recording width portion and the remaining portion have substantially the same recording density.

  In the invention according to appendix 18, in any one of appendices 1 to 5, the difference in recording density between the predetermined recording width portion and the remaining portion is 0.3 or less in the boundary portion. In the invention according to appendix 19, in the invention according to appendix 18, the amount of dye contained in the ink having higher permeability in the predetermined hue is larger than the amount of dye contained in the ink having lower permeability in the predetermined hue.

  In the invention according to appendix 20, in the invention according to appendix 18, the amount of ink to which the lower permeability ink in the predetermined hue adheres per unit area in the remaining portion of the boundary portion is the predetermined hue. The ink having the higher permeability is larger than the amount of ink deposited per unit area within the predetermined recording width portion of the boundary portion.

  In the inkjet recording apparatus for recording an image by attaching a plurality of hue inks to a recording medium according to appendix 21, the first problem is that at least one predetermined hue has permeability to the recording medium. Using two different types of ink, a head portion having a number of heads corresponding to the type of ink, a first recording area including the predetermined hue on the recording medium, and a hue different from the predetermined hue In the boundary portion between the first recording area and the second recording area adjacent to the first recording area, recording is performed over at least a predetermined recording width up to the second recording area with the ink having the higher permeability of the two types of ink. And the remaining part of the boundary part can also be achieved by an ink jet recording apparatus provided with a control means for controlling the head unit so as to perform recording with the ink having the lower permeability of the two types.

  In the invention according to appendix 22, in the invention according to appendix 21, the head portion uses ink whose brightness of the predetermined hue is lower than the brightness of other hues. In the invention according to appendix 23, in the invention according to appendix 21 or 22, the ink having the higher permeation in the predetermined hue used by the head unit and the ink of the other hue having the same higher permeation are the lightness of the hue. The lower the value, the higher the permeability.

  In the invention described in appendix 24, in any one of appendices 21 to 23, the predetermined hue of the ink used by the head unit is black. In the invention according to appendix 25, in the invention according to appendix 24, the other hues of the ink used by the head portion are yellow, magenta and cyan, respectively.

  In the invention according to appendix 26, in any one of appendices 21 to 25, the control unit controls the head unit so as to record ink having a hue with low lightness first. In the invention according to appendix 27, in any one of appendices 21 to 25, the control means may be configured such that the first recording area and the remaining portion of the boundary portion are the ones having lower permeability with the predetermined hue. Recording is performed with ink, and then the second recording area is recorded with ink of a hue other than the predetermined hue, and then the portion with the predetermined recording width is sequentially recorded with the ink having the higher permeability with the predetermined hue. The head unit is controlled as follows.

  In the invention according to appendix 28, in any one of the appendices 21 to 25, when the remaining portion of the boundary portion is larger than the portion of the predetermined recording width, the control means Then, the head unit is controlled so that the recording with the ink with the higher permeability is performed before the recording with the ink with the lower permeability at the predetermined hue.

  In the invention according to appendix 29, in any one of appendices 21 to 25, the control means is configured so that the predetermined hue is determined when the remaining portion of the boundary portion is smaller than the portion of the predetermined recording width. The head unit is controlled so that the recording with the ink having the lower permeability is performed before the recording with the ink having the higher permeability at the predetermined hue.

  In the invention according to appendix 30, in any one of appendices 21 to 25, when the remaining portion of the boundary portion is larger than the portion of the predetermined recording width, the control means The head unit is controlled so that the recording with the ink having the lower permeability is performed before the recording with the ink having the higher permeability at the predetermined hue.

  In the invention according to supplementary note 31, in any one of supplementary notes 21 to 25, the control means is configured such that the remaining portion of the first recording area and the boundary portion is the one having the lower permeability with the predetermined hue. Recording is performed with ink, and after a predetermined time, the head portion is controlled so that a portion having the predetermined recording width is recorded with the ink having the higher permeability and the predetermined hue, and the permeation is performed with the predetermined hue for the predetermined time. It is set longer than the familiar time of the ink having the lower property to the recording medium.

  In the invention according to appendix 32, in any one of the appendices 21 to 25, the predetermined recording width is adjusted based on at least one of the amount of ink that records the boundary portion and the permeability of the ink. Is done. In the invention according to appendix 33, in any one of appendices 21 to 25, the control means records at least one of the first and second areas with ink of two or more hues. The head unit is controlled as follows.

  In the invention according to appendix 34, in any one of appendices 21 to 25, in the boundary portion, the portion of the predetermined recording width and the remaining portion have substantially the same brightness or saturation. In the invention according to appendix 35, in the invention according to appendix 34, the color difference between the predetermined recording width portion and the remaining portion is 5 or less in the boundary portion.

  In the invention according to appendix 36, in the invention according to any one of appendices 21 to 25, the ink having higher permeability in the predetermined hue and the ink having lower permeability in the predetermined hue used in the head unit Use the same dye. In the invention according to appendix 37, in any one of appendices 21 to 25, at the boundary portion, the predetermined recording width portion and the remaining portion have substantially the same recording density.

  In the invention according to appendix 38, in any one of the appendices 21 to 25, in the boundary portion, a difference in recording density between the predetermined recording width portion and the remaining portion is 0.3 or less. In the invention according to appendix 39, in the invention according to appendix 38, the amount of dye contained in the ink having higher permeability in the predetermined hue used by the head portion is included in the ink having lower permeability in the predetermined hue. More than dye amount.

  In the invention according to appendix 40, in the invention according to appendix 38, the control means is configured such that the amount of ink to which the ink having the lower permeability in the predetermined hue adheres per unit area in the remaining portion of the boundary portion is The head portion is controlled so that the ink having the higher permeability in the predetermined hue is larger than the amount of ink deposited per unit area within the predetermined recording width portion of the boundary portion.

  According to the inventions described in Appendices 41 to 49, it is possible to record line images such as high-quality characters without bleeding and general images such as high-quality graphics without bleeding. It is possible to suppress the difference in recording density and hue. According to the inventions of Supplementary Notes 50 and 51, it is possible to prevent bleeding at a boundary portion of different hues and record a clear color image.

  According to the inventions of Supplementary Notes 52 to 55, line drawings and general images can be recorded with high quality on various types of recording media including plain paper. According to the inventions of Supplementary Notes 56 to 59, it is possible to record line images such as high-quality characters without bleeding and general images such as high-quality graphics without bleeding. It is possible to suppress the difference in recording density and hue.

  According to the inventions of Supplementary Notes 60 to 64, it is possible to perform recording of line drawings such as high-quality characters without bleeding and recording of general images such as high-quality graphics without bleeding. It is possible to suppress the difference in recording density and hue. According to the inventions of Appendices 65 and 66, bleeding at the boundary portion of different hues can be prevented and a clear color image can be recorded.

  According to the inventions in appendixes 67 to 70, line drawings and general images can be recorded with high quality on various types of recording media including plain paper. According to the inventions described in Appendices 71 to 74, it is possible to record line images such as high-quality characters without bleeding and general images such as high-quality graphics without bleeding. It is possible to suppress the difference in recording density and hue.

According to the first aspect of the present invention, it is possible to improve the recording speed and to reduce the ink consumption by minimizing the spraying condition of the head for preventing the ink thickening that causes dot dropout and dot deviation. Can be reduced.

According to the second and third aspects of the invention, the ink thickening is adjusted according to the frequency of use of the head, so that the spraying condition of the head can be suppressed to the minimum regardless of the number of heads. According to the fourth aspect of the present invention, the recording speed is improved and the ink consumption is reduced by minimizing the spray conditions of the head for preventing ink thickening that causes dot omission and dot deviation. Can be reduced.

According to the fifth and sixth aspects of the invention, the ink thickening is adjusted according to the frequency of use of the head, so that the spraying condition of the head can be suppressed to the minimum regardless of the number of heads.

  According to the inventions described in Appendices 1 to 20, it is possible to perform recording of line drawings such as high-quality characters without blurring and recording of general images such as high-quality graphics without bleeding. It is possible to suppress the difference in recording density and hue.

  According to the inventions described in Appendices 21 to 40, it is possible to record line images such as high-quality characters without bleeding and general images such as high-quality graphics without bleeding. It is possible to suppress the difference in recording density and hue.

  According to the inventions described in Appendices 41 to 49, it is possible to record line images such as high-quality characters without bleeding and general images such as high-quality graphics without bleeding. It is possible to suppress the difference in recording density and hue.

  According to the supplementary notes 50 and 51, it is possible to prevent bleeding at the boundary between different hues and record a clear color image. According to the inventions of Supplementary Notes 52 to 55, line drawings and general images can be recorded with high quality on various types of recording media including plain paper.

  According to the inventions of Supplementary Notes 56 to 59, it is possible to record line images such as high-quality characters without bleeding and general images such as high-quality graphics without bleeding. It is possible to suppress the difference in recording density and hue. According to the inventions of Supplementary Notes 60 to 64, it is possible to perform recording of line drawings such as high-quality characters without bleeding and recording of general images such as high-quality graphics without bleeding. It is possible to suppress the difference in recording density and hue.

  According to the inventions of Appendices 65 and 66, bleeding at the boundary portion of different hues can be prevented and a clear color image can be recorded. According to the inventions in appendixes 67 to 70, line drawings and general images can be recorded with high quality on various types of recording media including plain paper.

  According to the inventions described in Appendices 71 to 74, it is possible to record line images such as high-quality characters without bleeding and general images such as high-quality graphics without bleeding. It is possible to suppress the difference in recording density and hue.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, a first embodiment of an ink jet recording apparatus according to the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing a main part of a first embodiment of the ink jet recording apparatus, and FIG. 2 is a perspective view showing a head part. In the first embodiment of the ink jet recording apparatus, the first embodiment of the ink and ink cartridge used in the ink jet recording apparatus and the ink jet recording method is used.

  In FIG. 1, an ink jet recording apparatus 40 is generally composed of a frame 41, a carrier 42, a stage shaft 43, a paper feed roller 44, a head unit 45, a backup unit 46, a motor 47, a belt 48, and the like. The carrier 42 is driven by a motor 47 through a belt 48, is guided by a stage shaft 43, and can move in the X direction in FIG. The head unit 45 is attached to the carrier 42. The recording medium 50 such as paper is fed by the paper feed roller 44, and the head unit 45 records (prints) an image on the recording medium 50 based on image data received from a host device (not shown), for example.

  The backup unit 46 is provided as a protection mechanism for the head unit 45. The backup unit 46 caps the nozzle surface of the head unit 45 when the head unit 45 is on standby to prevent clogging or the like, and when a predetermined operation is performed by the user, the dot missing due to clogging or the like is eliminated. In order to recover, it has a function of sucking and discharging ink and bubbles from the nozzles of the head unit 45.

  Since the ink jet recording apparatus 40 composed of the frame 41, the carrier 42, the stage shaft 43, the paper feed roller 44, the backup unit 46, the motor 47, the belt 48, etc., each can use a known configuration. A detailed description of the structure and operation is omitted.

  Next, the configuration of the head unit 45 will be described with reference to FIG. FIG. 2 shows the head 45 with the cover removed. In FIG. 2, the head portion 45 has a housing 51, and the housing 51 is provided with a plurality of detachable levers 5-1 to 5-5. Further, slots 52 are provided at positions corresponding to the attachment / detachment levers 5-1 to 5-5 of the housing 51, respectively. The ink cartridges 11-1 to 11-5 are inserted into the corresponding slots 52, and can be attached to and detached from the corresponding print heads (not shown) by operating the attachment / detachment levers 5-1 to 5-5, respectively. Since the print head has a nozzle for ejecting ink, and a known print head can be used for the print head itself, its illustration and detailed description are omitted in this specification. In FIG. 2, only the ink cartridge 5-1 is shown before being completely inserted into the slot 52 or withdrawn from the slot 52. In this embodiment, five print heads are provided in the lower part of the housing 51 corresponding to the five ink cartridges 11-1 to 11-5, but cannot be seen in FIG. Each of the ink cartridges 11-1 to 11-5 and each of the print heads may basically have a known configuration, and each print head has one or a plurality of nozzles that eject ink.

  For example, each of the ink cartridges 11-1 to 11-4 includes a cartridge body that stores black, yellow, magenta, and cyan inks used for color recording. The ink cartridge 5-5 has a cartridge body that is slightly larger than the other ink cartridges 11-1 to 11-4, and stores black ink used during monochrome recording. Therefore, in this embodiment, black ink is supplied from different ink cartridges for color recording and monochrome recording. With such a configuration, for example, it is possible to use print heads having different structures for the print heads corresponding to the ink cartridges 11-1 to 11-4 and the print head corresponding to the ink cartridge 5-5. .

  In this embodiment, the composition of the black, yellow, magenta, and cyan inks stored in the ink cartridges 11-1 to 11-4 is, for example, 2% by weight of an acid dye, 10% by weight of glycerin, and an anionic surfactant. 0.5% by weight and remaining water. The composition of the black ink stored in the ink cartridge 11-5 is, for example, 2% by weight of direct dye, 10% by weight of glycerin, 4% by weight of isopropanol, and remaining water. The inks of these compositions were obtained by weighing each type of ink in a sealed plastic container, stirring and dissolving for 3 hours while bathing at 50 ° C., cooling to room temperature, and filtering with a filter having a pore size of 0.2 μm. . The black ink stored in the ink cartridge 11-5 penetrates into the recording medium 50 as compared with the black, yellow, magenta, and cyan ink stored in the ink cartridges 11-1 to 11-4. The composition is such that the properties are low. For example, the permeation time into the copy quality paper was about 25 seconds for the black ink for monochrome stored in the ink cartridge 11-5 and about 3 seconds for the other inks.

  FIG. 3 is a diagram schematically showing an enlarged photograph of a recording result when characters “ABC” are recorded on a high-quality copy paper with a resolution of 360 dpi using these inks. In the same figure, (a) shows the recording result when recording is performed with black and white ink stored in the ink cartridge 11-5, and (b) is stored in the ink cartridge 11-1. The recording result when recording with the black ink for color is shown. As can be seen from the figure, the penetrability stored in the ink cartridge 11-1 is obtained when recording is performed with the black ink for monochrome having low penetrability stored in the ink cartridge 11-5. Compared with recording with high-quality black ink for color, high-quality recording without ink bleeding can be performed. In particular, in FIG. 6B, since the ink permeability is high, the ink bleeds greatly, the fine portions of the characters are crushed, the edge is not sharp, and the recording quality is the same as in FIG. It can be seen that it has dropped significantly. Therefore, in this embodiment, when the image to be recorded is monochrome, or when the image to be recorded is black and does not have a portion in contact with another hue, recording is performed with black ink for monochrome with low permeability. Do.

  On the other hand, in this embodiment, for example, when recording an image having a portion where yellow and black are in contact with each other, only a part of the boundary portion between the black region and the yellow region is recorded with highly penetrating black ink for color, The other part of the black area is recorded with black ink for monochrome having low permeability.

  FIG. 4 is a diagram schematically showing an enlarged bleed state in a photograph of a recording result when an image composed of yellow and black is recorded. In this figure, (a) shows only the 6-dot width of the boundary portion x with the yellow region Y in the black region B in the present embodiment, and is recorded with highly penetrating color black ink. (B) schematically shows an enlarged photograph of the recording result when recording with black ink for monochrome having low permeability, and (b) shows monochrome with low permeability for the entire black area B including the boundary portion x. (C) is an enlarged view schematically showing a photograph of a recording result when recording with black ink for printing, and (c) shows a case where the entire black area B including the boundary portion x is recorded with black ink for color having high permeability. (D) schematically shows an enlarged photograph of the recording result when recording was performed with a non-recording portion (whitened portion) provided at the boundary portion x. In the present embodiment, as shown in FIG. 9A, recording with less bleed can be realized as in the case of FIG. However, in FIG. 5B, the bleed is remarkably large, and in FIG. 4D, the white area is remarkably recognized at the boundary portion x. In these cases, the recording result is as large as the desired image to be recorded. It was confirmed that it was different.

  In FIG. 4C, the recording density of the black region B is lower than that of the character shown in FIG. 3A, and the color difference between the black character and the black region B can be recognized. The quality of the entire image is degraded. In contrast, in this embodiment, as shown in FIG. 4A, the recording density of the black region B is high, and the color difference between the character and the black region B shown in FIG. It was.

  Therefore, as shown in FIG. 3A and FIG. 4A, according to this embodiment, high-quality character recording without blur and high-quality color boundary recording without bleeding are realized at the same time. it can. Further, since the recording density, brightness, and saturation of characters and graphics can be made equal, the quality of the entire recorded image can be remarkably improved.

  In the black region B, the effect of reducing bleeding is increased as the width of the boundary portion x recorded with the black ink for color having high permeability is increased. However, as the dot width of the boundary portion x increases, the difference in brightness, saturation, and recording density increases to a level that can be recognized. Therefore, the color difference can be reduced by making the types of the dyes used in the two types of black ink for monochrome with low penetrability and the color black ink with high penetrability the same. Further, as will be described later with reference to the fourth embodiment, the difference in recording density is reduced by making the dye density of the black ink for color having high penetrability higher than that of the black ink for monochrome having low penetrability. Can do.

  FIG. 5 shows that the dye of black ink for color with high penetrability is the same direct dye as used for black ink for monochrome with low penetrability from acid dye, and the composition ratio of dye is from 2% by weight. It is a figure which expands and shows typically the photograph of the recording result at the time of recording using the black ink of the adjusted high permeability obtained by increasing to 4 weight%. As is clear from the comparison between FIG. 4 and FIG. 4A, in FIG. 5, the bleed is as small as in FIG. 4A and the black boundary is difficult to recognize. It was confirmed that the uniformity of the was improved.

  This will be described in more detail together with the fourth and fifth embodiments described later. The present inventors conducted subjective evaluation using samples of various hues, and when the color difference is 5 or less, the difference in brightness and saturation is determined. It was confirmed that the color difference between the areas recorded with inks having different penetrability is preferably 5 or less. In addition, when subjective evaluation was performed on the recording density of the recording area of the same hue, when the recording density (OD) measured by the Macbeth densitometer was about 1.0 or more, recording between the recording areas of the same hue was performed. If the density difference was 0.3 or less, it was confirmed that the density difference was within the allowable range. Therefore, it was found that the difference in recording density between the recording area recorded with the ink having high permeability and the recording area recorded with the ink having low permeability is preferably 0.3 or less in OD.

  Ink with low permeability tends to be small on the recording medium. For this reason, when recording is performed using both low penetrability ink and high penetrability ink, less penetrable ink may be adhered per unit area than high penetrability ink. desirable. By doing so, it is possible to record dots suitable for a predetermined resolution of the ink jet recording apparatus.

  Improves the quality of the recorded image by adjusting the width of black ink with high penetrability at the border by adjusting the amount of ink in each color area that forms the border and the penetrability of the ink in the recording medium itself. can do. In other words, since the bleed tends to increase as the amount of ink increases and the ink permeability of the recording medium itself decreases, the width of recording with black ink having high permeability at the boundary portion should be set wider. It is effective.

  FIG. 6 is a photograph of a recording result when recording is performed using black ink having high permeability at the boundary portion x between the yellow area Y and the black area B on a recording medium having the first ink permeability. It is a figure which expands and shows the state of a bleed typically. In the figure, (a), (b), (c), and (d) are the cases where the recording width of the boundary portion x with black ink having high permeability is 1 dot, 2 dots, 4 dots, and 6 dots, respectively. Indicates the bleed state.

  FIG. 7 shows the results of recording when recording is performed using black ink having high permeability at the boundary portion x between the red region R and the black region B on a recording medium having the first value of ink permeability. It is a figure which expands and shows the state of the bleed in a photograph typically. The red region R is obtained by overlapping recording of yellow and magenta inks, and the amount of ink used is approximately twice that of the case where the yellow region Y is recorded with yellow ink. In the figure, (a), (b), (c), and (d) are the cases where the recording width of the boundary portion x with black ink having high permeability is 1 dot, 2 dots, 4 dots, and 6 dots, respectively. Indicates the bleed state.

  As can be seen from FIG. 6 and FIG. 7, the bleed was reduced as the recording width of the boundary portion x with the black ink having low permeability was increased. In addition, the bleed at the boundary between the black region B and the red region R tended to be larger than the boundary between the black region B and the yellow region Y. In order to reduce the bleed and obtain the same recording quality, the recording width of the boundary portion x by the black ink having high penetrability is about 4 dots at the boundary between the black area B and the yellow area Y where the ink amount is small. About 6 dots are required at the boundary between the black region B and the red region R, which have a large amount. In this way, at the boundary where the amount of ink is large, widening the recording width of the boundary portion x with black ink having high penetrability (in this example, increasing the number of dots) reduces bleed and provides equivalent recording quality. It is effective in obtaining.

  FIG. 8 shows a case where recording is performed using black ink having high permeability at the boundary portion x between the yellow area Y and the black area B on a recording medium having a second value whose ink permeability is lower than the first value. It is a figure which expands and shows typically the state of the bleed in the photograph of the recording result. In the figure, (a), (b), (c), and (d) are the cases where the recording width of the boundary portion x with black ink having high penetrability is 2, 4, 6, and 8 dots, respectively. Indicates the bleed state.

  FIG. 9 shows the result of recording when recording is performed using black ink having high permeability at the boundary portion x between the red region R and the black region B on a recording medium having a second ink permeability. It is a figure which expands and shows the state of the bleed in a photograph typically. The red region R is obtained by overlapping recording of yellow and magenta inks, and the amount of ink used is approximately twice that of the case where the yellow region Y is recorded with yellow ink. In the figure, (a), (b), (c), and (d) are the cases where the recording width of the boundary portion x with black ink having high penetrability is 2, 4, 6, and 8 dots, respectively. Indicates the bleed state.

  As can be seen from a comparison between FIG. 8 and FIG. 9 and FIG. 6 and FIG. In order to reduce the bleed and obtain the same recording quality, the recording width of the boundary portion x by the black ink having high penetrability is about 6 dots at the boundary between the black area B and the yellow area Y where the ink amount is small. About 8 dots are required at the boundary between the black region B and the red region R, which have a large amount. As described above, adjusting the recording width (number of dots) with black ink having high permeability at the boundary portion x according to the permeability of the recording medium reduces bleed and obtains equivalent recording quality. It is effective.

  FIG. 10 is a diagram for explaining the bleed state according to the brightness (contrast) difference between adjacent regions. In the figure, (a) schematically shows an enlarged photograph showing the bleed state at the boundary between the black region B and the red region R where the brightness difference between black and black is large, and (b) shows the black region B. An enlarged photograph schematically showing a bleed state at the boundary portion between the black region and the purple region P where the brightness difference between the black and the black region is small. In FIG. 10, the recording width at the boundary portion with the black ink having high permeability is 2 dots. In FIG. 10A, bleed at the boundary portion can be recognized, but in FIG. 10B, bleed at the boundary portion can hardly be recognized. As described above, since the bleed looks particularly remarkable at the color boundary where the difference in brightness (contrast) is large, the present embodiment is particularly effective when applied to a case where the brightness difference between the colors of the inks recording adjacent areas is large. It is.

  FIG. 11 is a diagram for explaining the bleed state when recording is performed by changing the permeability of the highly permeable ink to be used at the boundary between adjacent areas. In the same figure, (a) shows the bleed state at the boundary when the penetrability of the black ink used in the black region B is increased and the penetrability of the yellow ink used in the yellow region Y is lowered. (B) shows a case where the permeability of the black ink used in the black area B is lowered and the permeability of the yellow ink used in the yellow area Y is increased. The photograph which shows the state of the bleed in the boundary part of this is enlarged and shown typically. The composition of the highly penetrating ink used is that the less penetrating ink has a surfactant amount of 0.3%, and the more penetrating ink has a surfactant amount of 0.5%. As a result, two types of inks were adjusted for each color to change the permeability of the ink, and recording was performed with a combination of each ink.

  When the penetrability of the black ink was higher than that of the yellow ink, no bleed was seen as shown in FIG. On the other hand, when the penetrability of the yellow ink is made higher than that of the black ink, the black ink flows into the yellow region Y as shown in FIG. Looked like.

  Thus, when recording two adjacent areas with two types of highly penetrable inks having different penetrability, for example, when a low-brightness color ink such as black flows into a high-brightness ink such as yellow, for example, The bleed at the boundary will be noticeable. For this reason, when recording two adjacent areas with two types of inks that have both high penetrability and different penetrability, the lighter ink such as yellow has a lightness such as black. Setting the penetrability of the low-lightness ink higher than that of the high-lightness ink so that it flows into the low-color ink is effective in eliminating bleeding at the boundary and improving the recording quality. is there.

  In addition, when recording using highly penetrating ink, recording with low lightness ink is performed first so that ink with high lightness can easily flow into ink with low lightness, and ink fixing is performed first. If the recording with the next highest lightness ink is performed after the process is advanced, it is more effective in eliminating the bleed at the boundary and improving the recording quality.

  FIG. 12 is a diagram for explaining the dependency of the bleed state at the boundary portion on the recording order when recording is performed using two types of black ink having different penetrability and inks of other hues having high penetrability. It is. In the figure, (a) is an enlarged schematic view of a photograph of the recording results when recording is performed in the order of black ink with low permeability, yellow ink with high permeability, and black ink with high permeability. Show. In the figure, (b) schematically shows an enlarged photograph of a recording result when recording is performed in the order of yellow ink with high permeability, black ink with low permeability, and black ink with high permeability. Show. In the figure, (c) is a schematic enlarged view of a photograph of a recording result when recording is performed in the order of black ink with low permeability, black ink with high permeability, and yellow ink with high permeability. Show. In FIG. 12, the recording width of the boundary portion with black ink having high penetrability is 2 dots.

  In this embodiment, recording is performed in the order of black ink with low penetrability, ink of another hue such as yellow with high penetrability, and black ink with high penetrability. For this reason, as shown in FIG. 12A, there is almost no bleeding at the boundary. However, in the case of other recording orders as described above, as shown in FIGS. 1212 (b) and 12 (c), bleeding at the boundary portion is noticeable.

  Accordingly, when recording is performed with two types of black ink having different penetrability, and inks with other hues having high penetrability, recording with inks with other hues is performed between two types of black ink. It is desirable to adopt a recording order that performs the above. By adopting such a recording order, the black ink can be fixed for a relatively long time, and the time until the black ink comes into contact with each other can also be made relatively long. The density unevenness of the region can be suppressed.

  Further, if the recording area of black ink with low penetrability is larger than the recording area of black ink with high penetrability in the vicinity, recording with black ink with high penetrability is performed. It is desirable to carry out before recording with ink. As described above, by performing recording with black ink having high penetrability first, bleeding and density unevenness at the boundary portion can be reduced, and high-quality recording becomes possible. That is, by recording in this way, the ink with low penetrability flows into the recording area of the ink with high penetrability, the amount of recording ink increases, and the density of the black recording area is made uniform.

  FIG. 13 is a diagram for explaining the bleed state at the boundary portion when the recording order is changed with black ink having different permeability as described above. FIG. 6A shows the result of recording when recording with a black ink with low penetrability is first performed with a recording width of 48 dots, and then recording with black ink with a high penetrability is performed with a width of 8 dots. The photograph is enlarged and shown schematically. FIG. 4B shows a recording when recording with black ink having high penetrability is performed first with a recording width of 8 dots, and then recording with black ink having low penetrability is performed with a width of 48 dots. The photograph of a result is expanded and shown typically. In the case of FIG. 13, recording with yellow ink having high penetrability was performed between two types of black ink recording.

  As can be seen from FIG. 13, in the case of FIG. 13A, no bleed is seen at the boundary portion, and no density unevenness is seen in the black recording area. On the other hand, in the case of FIG. 5B, the density unevenness in the black recording area was noticeable. In addition, if the recording area of black ink with low penetrability is larger than the recording area of black ink with high penetrability in the surrounding area, the penetrating phenomenon is also prevented in order to prevent the ink from penetrating into the recording medium. It is desirable to perform recording with black ink having low property before recording with black ink having high permeability. The back-through of the ink to the recording medium is a phenomenon that the ink oozes out to the back surface of the recording medium, which is not preferable in consideration of recording on both sides of the recording medium. However, by performing recording with black ink having low penetrability first, it is possible to reduce such penetration of ink onto the recording medium. In other words, by recording black ink with low penetrability first, it is difficult for black ink with low penetrability to flow into the recording area of black ink with high penetrability, and the amount of ink in the recording area of black ink with high penetrability increases. Prevents back-throwing.

  FIG. 14 is a diagram for explaining the state of the back surface of the recording medium in the case where the recording order with different penetrable black inks is changed as described above. FIG. 4A shows that the recording with black ink having a low permeability is first performed with a recording width of 48 dots on the surface of the recording medium, and then the recording with black ink having a high permeability is 8 dots wide. Fig. 2 schematically shows an enlarged photograph of the back surface of a recording medium when performed in the above. FIG. 4B shows that the recording with black ink having high penetrability is first performed with a recording width of 8 dots on the surface of the recording medium, and then recording with black ink having low penetrability is performed for 48 times. The photograph of the back surface of the recording medium when performed with the dot width is schematically shown in an enlarged manner. In the case of FIG. 14, recording with yellow ink having high penetrability was performed between two types of black ink recording. In FIG. 1414, the satin pattern schematically indicates the color density on the back surface of the recording medium.

  As can be seen from FIG. 14, in the case of FIG. 14 (a), there is almost no see-through to the recording medium. On the other hand, in the case of (b) in FIG. By the way, if the recording area of black ink with low penetrability is smaller than the recording area of black ink with high penetrability around it, recording with black ink with low penetrability is performed. It is desirable to carry out before recording with ink. As described above, by performing recording with black ink having low permeability first, bleeding and density unevenness at the boundary portion can be reduced, and high-quality recording can be performed. That is, when recording is performed in this way, it is possible to prevent the ink having low permeability from flowing into the recording area of the ink having high permeability, and to prevent the density of the recording area of the ink having low permeability from being lowered.

  FIG. 15 is a diagram for explaining the bleed state at the boundary when the recording order is changed with black ink having different permeability as described above. FIG. 4A shows the result of recording when recording with black ink having a low penetrability is performed first with a recording width of 4 dots, and then recording with black ink having a high penetrability is performed with a width of 6 dots. The photograph is enlarged and shown schematically. FIG. 6B shows a recording when recording with black ink having a high penetrability is performed first with a recording width of 6 dots, and then recording with black ink having a low penetrability is performed with a width of 4 dots. The photograph of a result is expanded and shown typically. In the case of FIG. 15, the recording with yellow ink having high penetrability was performed between the recordings with two types of black ink.

  As can be seen from FIG. 15, in the case of FIG. 15 (a), no bleed is observed at the boundary and no uneven density is observed. On the other hand, in the case of FIG. 5B, the density unevenness in the black recording area was noticeable. High-quality paper and medium-quality paper used for copy paper and the like are subjected to an ink bleed prevention process called normal size. For this reason, when ink is attached to such a recording medium, the ink becomes familiar with the surface of the recording medium in a predetermined time called the familiarization time, and thereafter, penetration into the inside of the recording medium starts. In general, an ink with low penetrability has a longer familiar time than an ink with high penetrability, and the penetrating speed after the acclimatization time is slow. Therefore, when recording adjacent areas with highly permeable ink and low permeable ink, the time that the low permeable ink is present on the surface of the recording medium is long, and the highly permeable ink is present on the surface of the recording medium. The time that exists is short. For this reason, when the adjacent area is recorded with these two inks, the ink flows from the area recorded with the low penetrable ink to the area recorded with the high penetrable ink, and the recording density becomes dark or shaded. There may be a show-through. Therefore, when two inks having different penetrabilities are used, it is possible to avoid these problems and realize high-quality recording by adjusting the ink penetrating timing as described above.

  That is, an ink having a low penetrability, which has a low penetrability, adheres to the recording medium earlier than an ink having a high penetrability. It is desirable to start to penetrate into the recording medium. By performing such recording, it is possible to reduce the inflow of ink from an area recorded with ink having low permeability to an area recorded with ink having high permeability.

  FIG. 16 is a diagram showing the results of a Bristow test (J. TAPPI paper pulp test method No. 51) for inks with high permeability and low permeability. In the figure, a indicates the amount of penetration with respect to the contact time of the ink having low permeability, and b indicates the amount of penetration with respect to the contact time of the ink with high permeability.

  Ink with low penetrability does not easily penetrate into high-quality paper that has been subjected to a bleeding prevention process such as size, and can perform high-quality recording without bleeding. However, for recording paper with relatively high ink permeability, even with ink with low permeability, feather-like bleeding (feather) is likely to occur along the longitudinal direction of the fiber of the paper. Will be significantly reduced.

  On the other hand, when recording is performed with a highly permeable ink on a recording medium having a relatively high ink permeability, the feather can be reduced and the deterioration of the recording quality can be reduced. Therefore, when recording on a recording medium having a relatively high ink permeability, recording all the recording areas on the recording medium including the character portion with a highly permeable ink can reduce the feather. This is desirable.

  FIG. 17 is a diagram illustrating a recording result when recording is performed on a recording medium having relatively high ink permeability. In the figure, (a) schematically shows an enlarged photograph of a recording result when characters are recorded on recycled paper such as copy paper with black ink having high permeability, and (b) is low permeability. FIG. 2 schematically shows an enlarged photograph of a recording result when characters are recorded on recycled paper such as copy paper with black ink. As can be seen from FIG. 17, feathers are generated in FIG. 17B, but there are not so many feathers in FIG.

  In the above-described embodiment, two kinds of inks having different penetrability are used for black as examples of hues. Needless to say, it may be used for recording. In this case, the recording quality is further improved. Further, the hue is not limited to the above four colors, and inks having different penetrability can be similarly used for hues such as red, blue, and green.

  Next, the configuration and operation of the main part in the ink jet recording apparatus according to the present embodiment will be described in more detail with reference to FIGS. FIG. 18 is a block diagram showing an image data processing system in the first embodiment of the ink jet recording apparatus. In the figure, the image data processing system is generally composed of a boundary color determination unit 20 for black data, a separation unit 21 for black data, a dot control unit 22 and a drive unit 23. The black data boundary color discriminating unit 20 receives image data relating to an image to be recorded, and discriminates a hue in contact with a black portion in the image. The black data separation unit 21 separates from the image data the black data relating to the black portion recorded with black ink with high permeability and the black portion recorded with black ink with low permeability. The dot control unit 22 performs dot control including setting a recording width with black ink having low permeability at a boundary portion between a black portion and another hue portion. The driving unit 23 drives each head of the head unit 45 shown in FIG. 1 based on image data, black data, a recording width of black ink having low permeability at the boundary portion, and the like. The operations of the black data boundary color discriminating unit 20 and the black data separating unit 21 are realized by software stored in a memory 26 such as a single central control unit (CPU) 25 as shown by a broken line in FIG. Is possible. The operations of the dot control unit 22 and the drive unit 23 may also be realized by the software of the CPU 25. Further, the image data relating to the image to be recorded may be temporarily stored in the memory 26 or a buffer memory (not shown) and then read out and input to the boundary color determination unit 20 for black data.

  Since a control system for controlling the recording medium feeding mechanism such as the paper feeding roller 44 and a control system for controlling the movement of the carrier 42 are known, their illustration and description are omitted in this specification. First, operations of the black data boundary color determination unit 20, the black data separation unit 21, and the dot control unit 22 will be described. In the following description, as shown in FIG. 19, the dot recording position of the image data is represented by DXm, n, etc., X represents any hue of Y, M, C, K, K ′, and m, n Represents an integer. Here, hue X is recorded with yellow ink with Y being yellow and highly permeable, recorded with magenta ink having high permeability with M being magenta, and recorded with cyan ink having high permeability with C being cyan. It is assumed that K is recorded with black and highly permeable black ink, and K ′ is recorded with black and low permeable black ink. By combining the basic colors of these Y, M, C, K, and K ′ inks, an intermediate color can be realized. For example, R is red and R = Y + M, G is green and G = Y + C, and B is blue and B = M + C.

  FIG. 20 is a flowchart showing the operations of the black data boundary color discriminating unit 20, the black data separating unit 21, and the dot control unit 22 when the recording width of black ink having high penetrability at the boundary portion is 1 dot. . In the figure and the figures to be described later, dXm, n represents the image data of the hue X relating to the dot recording position DXm, n. The input color image data dXm, n does not include X = K ′.

  In FIG. 20, step S1 initializes m and n to 0, respectively. In step S2, it is determined whether or not the image data dKm, n relating to the dot recording position DKm, n is 1. If the determination result of step S2 is NO, the process proceeds to step S5 described later. On the other hand, if the decision result in the step S2 is YES, it is judged whether or not each hue image data other than black adjacent to each dot recording position DKm, n is 0 in a step S3. That is, image data dYm-1, n, dYm + 1, n, dYm, n-1, dYm, n + 1, dMm-1, n, dMm + 1, n, dMm, n-1, dMm, n + 1, dCm-1, n, When dCm + 1, n, dCm, n−1, and dCm, n + 1 are all 0, the determination result in step S3 is YES. If the decision result in the step S3 is YES, the image data dKm, n is set to 0 and the image data dK′m, n is set to 1 in a step S4. By this step S4, the image data dKm, n is not recorded with the black ink having high penetrability, and the image data dKm, n is replaced with the image data dK′m, n, and the black ink with low penetrability is used. Recording is performed.

  In step S5, it is determined whether m = a. If the determination result is NO, m is set to m + 1 in step S6, and the process returns to step S2. Here, a represents the final value of m. On the other hand, if the decision result in the step S5 is YES, it is judged whether or not n = b in a step S7. Here, b represents the final value of n. If the determination result in step S7 is NO, m is set to 0 and n is set to n + 1 in step S8, and the process returns to step S2. If the determination result in step S7 is YES, the process ends.

  As a result, at the boundary portion between the black region and the non-black hue region, the portion recorded with black ink with low penetrability is replaced by one dot with the portion recorded with black ink with high penetrability. That is, at the boundary portion, the recording width with black ink having high permeability is set to 1 dot.

  When the recording width of black ink having high penetrability is set to p dots at the boundary portion, basically, image data within the range of dXm ± p, n ± p in FIG. 20 is searched. good. FIG. 21 is a flowchart showing the operations of the black data boundary color discriminating unit 20, the black data separating unit 21, and the dot control unit 22 when the recording width of black ink having high penetrability at the boundary portion is p dots. .

  In FIG. 21, step S11 determines whether or not there is image data dXm, n for the dot recording position Dm, n, that is, whether or not printing with black or another hue should be performed. If the dot recording position Dm, n is white and the determination result in step S11 is NO, in step S12, m is set to m + 1 or n is set to n + 1 to search for the next dot recording position. In the initial state, m = 1 and n = 1, and the dot recording positions are sequentially searched from this state. Therefore, initially, in step S12, m is set to m + 1, and when a search is performed up to m = a, n is set to n + 1 in step S12, and the search is sequentially repeated until n = b. On the other hand, if the decision result in the step S11 is YES, it is decided in a step S13 whether or not the image data dXm, n for the dot recording position Dm, n is black, that is, dKm, n = 1. If the determination result in step S13 is NO, the process returns to step S12, but if YES, the process proceeds to step S14 described later.

  Through the above steps S11 to S13, it is determined whether or not recording with black or another hue is to be performed and the hue is determined. In step S14, whether or not image data dXx, y exists for any dot recording position Dx, y adjacent to the dot recording position Dm, n, that is, whether recording with black or another hue should be performed. Determine whether. Here, (x, y) is (m, n + 1), (m + 1, n), (m + 1, n + 1). If all the dot recording positions Dx, y are white and the determination result in step S14 is NO, the process proceeds to step S26. In step S26, the image data dKm, n is set to 0 and the image data dK'm, n is set to 1, and then the process returns to step S12. On the other hand, if the determination result in step S14 is YES, it is determined in step S15 whether the image data dXx, y for any dot recording position Dx, y is black, that is, dKx, y = 1. If the decision result in the step S15 is NO, a step S16 sets the image data dK′m, n to 0 and the process returns to the step S12. If the decision result in the step S15 is YES, it is decided whether or not the image data dKx, y for the two dot recording positions Dx, y is replaced with dK′x, y in a step S17. That is, in step S17, it is determined whether or not the recording width for recording with black ink having high permeability at the boundary portion is set to 2 dots. If the determination result of step S17 is NO, the process returns to step S12, and if YES, the process proceeds to step S18 described later.

  Through steps S14 to S17, the hue of the first adjacent dot is determined, and the recording width for recording with black ink having high permeability at the boundary portion is set to one dot. In step S18, whether or not the image data dXx, y for any dot recording position Dx, y adjacent to the dot recording position Dm, n exists, that is, whether recording with black or another hue should be performed. Determine whether. Here, (x, y) is (m, n + 2), (m + 1, n + 2), (m + 2, n), (m + 2, n + 1), (m + 2, n + 2). If all the dot recording positions Dx, y are white and the determination result in step S18 is NO, the process proceeds to step S26. On the other hand, if the decision result in the step S18 is YES, it is decided in a step 19 whether or not the image data dXx, y for any dot recording position Dx, y is black, that is, dKx, y = 1. If the decision result in the step S19 is NO, the step S20 sets the image data dK′m, n to 0 and the process returns to the step S12. If the decision result in the step S19 is YES, it is decided whether or not the image data dKx, y for the three dot recording positions Dx, y is replaced with dK′x, y in a step S21. That is, in step S21, it is determined whether or not the recording width for recording with black ink having high permeability at the boundary portion is set to 3 dots. If the determination result of step S21 is NO, the process returns to step S12. If YES, the process proceeds to step S22 described later.

  In steps S18 to S21, the hue of the second adjacent dot is determined, and the recording width for recording with black ink having high permeability at the boundary portion is set to 2 dots. In step S22, whether or not the image data dXx, y for any dot recording position Dx, y adjacent to the dot recording position Dm, n exists, that is, whether recording with black or another hue should be performed. Determine whether. Here, (x, y) is (m, n + 3), (m + 1, n + 3), (m + 2, n + 3), (m + 3, n), (m + 3, n + 1), (m + 3, n + 2), (m + 3, n + 3). It is. If all the dot recording positions Dx, y are white and the determination result in step S22 is NO, the process proceeds to step S26. On the other hand, if the decision result in the step S22 is YES, it is decided in a step 23 whether or not the image data dXx, y for any dot recording position Dx, y is black, that is, dKx, y = 1. If the decision result in the step S23 is NO, a step S24 sets the image data dK′m, n to 0 and the process returns to the step S12. If the decision result in the step S23 is YES, it is judged whether or not the image data dKx, y for the four dot recording positions Dx, y is replaced with dK′x, y in a step S25. That is, step S25 determines whether or not the recording width for recording with black ink having high permeability at the boundary portion is set to 4 dots. If the determination result of step S25 is NO, the process returns to step S12, and if YES, the process proceeds to the next step (not shown).

  Through steps S22 to S25, the hue of the third adjacent dot is determined, and the recording width for recording with black ink having high permeability at the boundary portion is set to 3 dots. Similarly, the above operation is repeated until the recording width for recording with black ink having high permeability at the boundary portion is set to p dots.

  Next, a black data boundary color discriminating unit 20 and a black data separating unit for adjusting the recording width for recording with black ink having high permeability in the color boundary portion according to the lightness difference between hues of adjacent regions 21 and the operation of the dot controller 22 will be described with reference to FIG. FIG. 22 is a flowchart showing the operations of the black data boundary color determination unit 20, the black data separation unit 21, and the dot control unit 22 in this case.

  In FIG. 22, the hue is represented by a numerical value. For convenience of explanation, in order of increasing brightness, whitening (no data) = 0, Y = 2, M = 3, C = 4, R (Y + M) = 5, G (Y + C) = 6, B (M + C) = 7 , K = K ′ = 9. The recording width for recording with black ink having high penetrability at the boundary portion, that is, the number of dots for replacing K ′ with K, in the order in which the brightness difference from black (K, K ′) is large and bleeding is conspicuous at the boundary portion. The operation when Y is 3 dots, M, C, R, and G are 2 dots, and B is 1 dot will be described below.

  In FIG. 22, step S31 determines whether or not there is image data dm, n for the dot recording position Dm, n, that is, whether or not dm, n ≠ 0 should be recorded in black or another hue. judge. When the dot recording position Dm, n is white and the determination result in step S31 is NO, in step S32, m is set to m + 1 or n is set to n + 1 to search for the next dot recording position. In the initial state, m = 1 and n = 1, and the dot recording positions are sequentially searched from this state. Accordingly, at first, m is set to m + 1 in step S32, and when the search is performed up to m = a, n is set to n + 1 in step S32 and the search is sequentially repeated until n = b. On the other hand, if the decision result in the step S31 is YES, it is judged whether or not the image data dm, n = 9 for the dot recording positions Dm, n, that is, dKm, n = 1, in a step S33. If the determination result of step S33 is NO, the process returns to step S32. If YES, the process proceeds to step S34 described later.

  Through the above steps S31 to S33, it is determined whether or not recording with black or another hue is to be performed and the hue is determined. In step S34, whether or not there is image data dx, y for any dot recording position Dx, y adjacent to the dot recording position Dm, n, that is, dx, y = ≠ 0, depending on black or another hue. It is determined whether recording should be performed. Here, (x, y) is (m, n + 1), (m + 1, n), (m + 1, n + 1). If all the dot recording positions Dx, y are white and the determination result in step S34 is NO, the process proceeds to step S45. In step S45, the image data dKm, n is set to 0 and the image data dK'm, n is set to 1, and then the process returns to step S32. On the other hand, if the decision result in the step S34 is YES, it is judged whether or not the image data dx, y for any dot recording position Dx, y is black, that is, dx, y = 9, in a step S35. If the decision result in the step S35 is NO, a step S36 sets the image data dK′m, n to 0 and the process returns to the step S32. If the decision result in the step S35 is YES, the process proceeds to a step S37 described later.

  By the steps S34 to S36, the hue of the first adjacent dot is determined, and the recording width for recording with black ink having high permeability at the boundary portion is set to 1 dot. In step S37, whether or not there is image data dx, y for any dot recording position Dx, y adjacent to the dot recording position Dm, n, that is, recording with dx, y ≠ 0 and black or another hue. It is determined whether or not should be performed. Here, (x, y) is (m, n + 2), (m + 1, n + 2), (m + 2, n), (m + 2, n + 1), (m + 2, n + 2). If all the dot recording positions Dx, y are white and the determination result in step S37 is NO, the process proceeds to step S45. On the other hand, if the decision result in the step S37 is YES, it is judged in a step 38 whether or not the image data dx, y for any dot recording position Dx, y is black, that is, dx, y = 9. If the decision result in the step S38 is NO, a step S39 decides whether or not the hue of dx, y is other than black by judging whether the dx, y is 0-7. If the decision result in the step S39 is YES, the process advances to a step S45. On the other hand, if the decision result in the step S39 is NO, the image data dK′m, n is set to 0 in a step S40, and the process returns to the step S32. If the decision result in the step S38 is YES, the process proceeds to a step S41 described later.

  Through steps S37 to S40, the hue of the second adjacent dot is determined, and the recording width for recording with black ink having high permeability at the boundary portion is set to 2 dots. In step S41, whether there is image data dx, y for any dot recording position Dx, y adjacent to the dot recording position Dm, n, that is, recording with dx, y ≠ 0 and black or other hue. It is determined whether or not should be performed. Here, (x, y) is (m, n + 3), (m + 1, n + 3), (m + 2, n + 3), (m + 3, n), (m + 3, n + 1), (m + 3, n + 2), (m + 3, n + 3). It is. If all the dot recording positions Dx, y are white and the determination result in step S41 is NO, the process proceeds to step S45. On the other hand, if the decision result in the step S41 is YES, it is decided in a step 42 whether or not the image data dx, y for any dot recording position Dx, y is black, that is, dx, y = 9. If the decision result in the step S42 is NO, a step S43 decides whether or not the hue of dx, y is other than yellow by judging whether the dx, y is other than 2. If the determination result of step S42 or S43 is YES, the process proceeds to step S45. On the other hand, if the decision result in the step S43 is NO, the image data dK′m, n is set to 0 in a step S44, and the process returns to the step S32.

  In steps S41 to S44, the hue of the third adjacent dot is determined, and the recording width for recording with black ink having high permeability at the boundary portion is set to 3 dots. Next, the black data boundary color discriminating unit 20 for adjusting the recording width for recording with black ink having high permeability in the color boundary portion according to the amount of ink for recording the adjacent area, separation of the black data Operations of the unit 21 and the dot control unit 22 will be described with reference to FIG. FIG. 23 is a flowchart showing the operations of the black data boundary color determination unit 20, the black data separation unit 21, and the dot control unit 22 in this case. In FIG. 23, the same steps as those in FIG.

  In FIG. 23, hue is represented by a numerical value. For convenience of explanation, in order of increasing brightness, whitening (no data) = 0, Y = 2, M = 3, C = 4, R (Y + M) = 5, G (Y + C) = 6, B (M + C) = 7 , K = K ′ = 9. When the primary colors Y, M, and C are overlapped to record the secondary colors R, G, and B, the amount of the secondary color ink is approximately twice that of the primary color. At this time, the recording width for recording with black ink having high penetrability is set to 1 dot at the primary color side of the boundary portion, and recording with black ink having high penetrability at the secondary color side portion of the boundary portion. The operation when the recording width to be set is set to 2 dots will be described below.

  In FIG. 23, if the decision result in the step S38 is YES, the process advances to a step S45. On the other hand, if the decision result in the step S38 is NO, a step S49 decides whether or not the dx and y are 4 or more, so that the hue of the dx and y is cyan or a hue having a lightness lower than that of the cyan. Determine whether or not. If the determination result of step S49 is YES, the process proceeds to step S45. On the other hand, if the decision result in the step S49 is NO, the image data dK′m, n is set to 0 in a step S44, and the process returns to the step S32.

  Next, a method for calculating the recording area recorded with black ink having high permeability and the recording area recorded with black ink having low permeability in the black area will be described with reference to FIG. FIG. 24 shows a black data boundary color discriminating unit 20 and a black data separating unit 21 for calculating a recording area recorded with black ink having high penetrability and a recording area recorded with black ink having low penetrability. 5 is a flowchart showing the operation of the dot control unit 22.

  In FIG. 24, the hue is represented by a numerical value. For convenience of explanation, in order of increasing brightness, whitening (no data) = 0, Y = 2, M = 3, C = 4, R (Y + M) = 5, G (Y + C) = 6, B (M + C) = 7 , K = K ′ = 9. Further, the ink jet recording apparatus adopts a serial recording method. For example, the recording area for recording with black ink having high penetrability for data of one scan of m = 1 to 2950 and n = 1 to 48, and The recording area to be recorded with black ink with low penetrability is calculated. Further, the black data is decomposed into black data dKm, n recorded with black ink with high permeability and black data dK′m, n recorded with black ink with low permeability by the above processing. It shall be.

  In FIG. 24, step S51 determines whether m <2950 or n <48 for the image data in the memory 26 or buffer memory shown in FIG. If the decision result in the step S51 is NO, the process advances to a step S59 described later. On the other hand, if the decision result in the step S51 is YES, whether or not the image data dm, n for the dot recording position Dm, n is dm, n = 9 in the step S52, that is, the image data dm, n is black. Judge whether to represent. If the determination result in step S52 is NO, m is set to m + 1 or n is set to n + 1 in order to search for the next dot recording position in step S53. In the initial state, m = 1 and n = 1, and the dot recording positions are sequentially searched from this state. Therefore, initially, in step S53, m is set to m + 1, and when a search is performed up to m = 2950, n is set to n + 1 in step S53, and the search is sequentially repeated until n = 48. On the other hand, if the decision result in the step S52 is YES, the process advances to a step S54 described later.

  In step S54, whether or not the image data dx, y for any dot recording position Dx, y adjacent to the dot recording position Dm, n is dx, y = 9, that is, whether dx, y represents black. Determine whether or not. Here, (x, y) is (m-1, n-1), (m, n-1), (m + 1, n-1), (m-1, n), (m + 1, n), ( m−1, n + 1), (m, n−1), (m + 1, n + 1), 1 ≦ x ≦ 2950, and 1 ≦ y ≦ 48. If the decision result in the step S54 is NO, the isolated dot is ignored and the process returns to the step S53. On the other hand, if the decision result in the step S54 is YES, the image data dpq is set to dpq = 9 in a step S55.

  In step S56, it is determined whether p = m−1 and q = n or q = n−1. If the decision result in the step S56 is NO, (m, n) is stored in the memory 26 or the new memory area Mr in the buffer memory in a step S57, and the process returns to the step S53. On the other hand, if the decision result in the step S56 is YES, the (m, n) is stored in the memory 26 storing the (p, q) or the existing memory area Mo in the buffer memory in a step S58. Here, o <r. After step S58, the process returns to step S53.

  If the determination result in step S51 is NO, step S59 calculates the number of image data dKv, w, dK'v, w corresponding to each coordinate (v, w) in the same existing memory area Mo. Thereby, the recording area is calculated. In step S60, the number calculated in step S59, that is, the calculated recording area is compared, and based on the comparison result, the recording area recorded with black ink having high penetrability and black having low penetrability are compared. The recording order with respect to the recording area to be recorded with the ink is determined. The driving unit 23 shown in FIG. 18 drives each head of the head unit 45 based on the recording order determined in this way.

  Next, a description will be given of a second embodiment of the ink jet recording apparatus according to the present invention. In the second embodiment of the ink jet recording apparatus, the second embodiment of the ink jet recording method according to the present invention and the second embodiment of the ink and ink cartridge used in the ink jet recording apparatus and the ink jet recording method are used. Since the configurations of the ink jet recording apparatus and the ink cartridge can be the same as those shown in FIGS. 1 and 2, their illustration and description are omitted.

  In this embodiment, when a color image is recorded using a plurality of different color inks including black ink, the Rf value of each color ink is set to satisfy a predetermined condition. That is, the Rf value of at least one ink is made different from the Rf value of the other inks, and the Rf value of the ink having a low lightness is lower than that of the ink having a high lightness.

  Here, the Rf value indicates the value of the migration rate of the color material obtained by the paper chromatography method specified below. That is, the color material having a higher Rf value has a lower affinity with the cellulose fiber on the plain paper and is likely to spread on the recording medium. The Rf value is obtained as follows.

  A desired color material is dissolved in a water / diethylene glycol mixed solvent having a weight ratio of 55/45 by 5% by weight to obtain a test liquid for performing the test. The test solution obtained in this way was traded with Toyo Filter Paper No. After 2 μl is charged to the lower end of the filter No. 50, development is performed for a predetermined time according to a conventional method using the above mixed solvent as a developing solvent. As a result of this development, the development distance A of the development solvent from the charge point and the movement distance B of the dye from the charge point are measured, and the ratio B / A = Rf is obtained.

  In this embodiment, water and a mixture of water and a water-soluble organic solvent are used for the ink jet recording liquid, that is, the liquid medium constituting the ink. Examples of organic solvents include monohydric alcohols such as methanol, ethanol, (normal) propyl alcohol, and isopropyl alcohol, dihydric alcohols such as ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, diethylene glycol, and triethylene glycol, and glycerin. Polyalkylene glycols such as trihydric alcohol, polyethylene glycol and polybutylene glycol, nitrogen-containing heterocyclic compounds such as N-methyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone, ethylene glycol monomethyl ether, diethylene glycol Lower alkyl ethers of polyhydric alcohols such as monomethyl ether and triethylene glycol monomethyl ether can be used. It may be use. In particular, among these, it is preferable to use a dihydric or higher polyhydric alcohol that is hard to evaporate and has a hygroscopic property.

  The content of the organic solvent in the ink is 5 to 80% by weight, preferably 5 to 50% by weight. This is because when the content of the organic solvent is less than 5% by weight, drying of the ink becomes faster or the solubility of the dye is lowered, and the dye in the ink is likely to be deposited and easily clogged. On the other hand, if it exceeds 80% by weight, the viscosity of the ink increases and it becomes difficult to eject the ink from the nozzles of the head.

  The basic composition of the ink used in this example is as described above, but other dispersants, cationic surfactants, anionic surfactants, nonionic surfactants, polyvinyl alcohol, celluloses, and water-soluble resins as necessary. Needless to say, a viscosity adjusting agent such as diethanolamine or triethanolamine may be added.

  The inventors first recorded a color image using yellow, magenta, cyan, and black inks having the following composition 1 and almost the same Rf value.

(Composition 1)
Dye 2% by weight Yellow: C.I. I. Acid Yellow 23, Rf value = 0.90 Magenta: C.I. I. Acid Red 265, Rf value = 0.91 Cyan: C.I. I. Acid Blue 120, Rf value = 0.91 Black: C.I. I. Acid Black 139, Rf value = 0.90 Diethylene glycol 10% by weight Ethyl alcohol 5% by weight Ethylene glycol dibenzyl ether 1% by weight Distilled water 88% by weight When the above composition 1 is used, as shown in FIG. An unintended color mixture, that is, a bleed 34 occurred at a boundary portion 33 where the solid recording area 31 and the solid recording area 32 of another color are adjacent to each other. Due to the bleed 34, the recorded image was unclear and only an image lacking sharpness was obtained. In particular, bleed that occurs at the boundary between different colors is noticeable at the boundary between yellow and other colors. This is due to the visual influence of the human eye, and is considered to appear to be blurred from the lower lightness to the higher lightness by the human eye at the boundary with the color having a large lightness difference.

  FIG. 26 is a diagram schematically showing the bleed in FIG. In FIG. 26, the same parts as those in FIG. 25 are denoted by the same reference numerals, and the description thereof is omitted. In FIG. 26, a blackish bleed region 34 in which yellow, magenta, and cyan are mixed is generated at a boundary portion 33 between the yellow region 31 and the blue region 32. Since the difference in brightness between the blackish color of the bleed region 34 and the blue color of the blue region 32 is relatively small, the bleed portion is hardly noticeable. However, since the brightness difference between the yellow color of the yellow region 31 and the blackish color of the bleed region 34 is large, the bleed portion is conspicuous. For this reason, it is considered that the human eye looks as if a bleed has occurred from the blue region 32 with low lightness toward the yellow region 31 with high lightness.

  Therefore, in this embodiment, the solvent composition ratio of each color ink is not changed, and the dye is selected so that the Rf value of the dye of the low brightness ink is lower than the Rf value of the dye of the high brightness color ink. To do. That is, as shown below, each Rf value is selected so that the Rf values Yr, Mr, Cr, and Kr of yellow, magenta, cyan, and black dyes satisfy the relationship of Yr> Mr ≧ Cr> Kr, respectively. In addition, the lower the lightness of the color ink, the larger the affinity with the cellulose fiber which is the main component of the paper used as the recording medium. As a result, bleeding can be made inconspicuous.

  The inventors recorded color images using yellow, magenta, cyan and black inks having the following composition 2 that satisfy these conditions.

(Composition 2)
Dye 2% by weight Yellow: C.I. I. Acid Yellow 23, Rf value = 0.90 Magenta: C.I. I. Acid Red 161, Rf value = 0.86 Cyan: C.I. I. Direct Blue 86, Rf value = 0.86 Black: C.I. I. Direct black 154, Rf value = 0.72 Diethylene glycol 10 wt% ethyl alcohol 5 wt% ethylene glycol dibenzyl ether 1 wt% distilled water 88 wt% It was confirmed that the bleed at the boundary portion of the film became almost inconspicuous. This is because the force for the yellow ink to flow into the other color ink is stronger than the force for the cyan, magenta and black inks to flow into the yellow ink. It is thought that it became difficult to invade the yellow area beyond the boundary. For the same reason, it was possible to prevent black ink from flowing into other color inks, and it was confirmed that a clear color image could be recorded.

  Furthermore, the present inventors examined the influence of the difference between the Rf values of the yellow and black inks used on the bleed by experiment, particularly when the yellow area and the black area where the bleed is conspicuous are recorded adjacent to each other. As a result, the relationship between the difference in Rf value and the degree of bleed is as shown in FIG. In FIG. 27, the horizontal axis indicates the difference in Rf values, and the vertical axis indicates the degree of bleeding by subjective evaluation. The value of the subjective evaluation is very satisfactory in the case of 5, satisfactory in the case of 4, acceptable in the case of 3, dissatisfied in the case of 2, and greatly dissatisfied in the case of 1, and the bleed is not conspicuous as the value is large. As can be seen from FIG. 27, in order for the subjective evaluation value to be 3 or more, the difference in Rf values is 0.04 or more, preferably 0.1 or more (to make the subjective evaluation value 4 or more). It was confirmed that there was a need.

  In the ink jet recording apparatus, when recording a color image using each color ink of the above composition 2, as described in the first embodiment, the recording is performed in order from the ink of the color with the lower brightness. It is desirable to do. This is because the ink that adheres to the recording medium later tends to be attracted to the ink that has adhered earlier, and thus bleed easily. According to the experiments by the present inventors, the effect of preventing bleeding was particularly improved when recording with black ink having a strong affinity with cellulose fibers was first performed and recording with yellow ink having a weak affinity was performed last. .

  Furthermore, the present inventors recorded a color image using yellow, magenta, cyan and black inks having the following composition 3 which satisfies the same conditions as the composition 2.

(Composition 3)
Yellow ink dye 2% by weight Yellow: C.I. I. Acid Yellow 23, Rf value = 0.90 diethylene glycol 10% by weight ethyl alcohol 5% by weight ethylene glycol dibenzyl ether 1% by weight anionic surfactant 0.5% by weight distilled water 87.5% by weight magenta ink dye 2% % Magenta: C.I. I. Acid Red 161, Rf value = 0.86 Diethylene glycol 10 wt% Ethyl alcohol 5 wt% Ethylene glycol dibenzyl ether 1 wt% Anionic surfactant 0.3 wt% Distilled water 87.7 wt% Cyan ink dye 2 wt % Cyan: C.I. I. Direct Blue 86, Rf value = 0.86 diethylene glycol 10% by weight ethyl alcohol 5% by weight ethylene glycol dibenzyl ether 1% by weight anionic surfactant 0.2% by weight distilled water 87.8% by weight black ink dye 2% % Black: C.I. I. Direct black 154, Rf value = 0.72 Diethylene glycol 10% by weight Ethyl alcohol 5% by weight Ethylene glycol dibenzyl ether 1% by weight Distilled water 88% by weight When the above composition 3 is used, a penetrating surfactant is added for each color. Since the ink is added for each ink, the permeability of the low-brightness color ink can be made lower than that of the high-brightness color ink. As a result, it was confirmed that the effect of preventing bleeding at the boundary portion was further improved.

  The inventors compared the permeability of each ink by the Bristow method, and as shown in FIG. 28, the familiarity time of the black ink with the lowest brightness was the shortest, and the familiarity time of the cyan and magenta inks. The familiarity time of yellow ink with the same high brightness was the longest. In FIG. 28, the horizontal axis represents the ink contact time on the recording medium, and the vertical axis represents the ink penetration amount. Y, M, C, and K correspond to yellow, magenta, cyan, and black inks, respectively. When the results of recording with these inks were examined, it was confirmed that bleeding was further reduced and a very clear color image could be recorded.

  By the way, in the conventional ink jet recording system, it is very difficult to obtain a satisfactory recording quality when commonly used paper such as notebook, report paper, copy paper, and stationery is used as a recording medium. This is because the ink adhering to the paper spreads along the fiber of the paper and causes bleeding. For this reason, thin ruled lines, fine characters, complicated kanji as defined in JIS Level 2 are often unclear and difficult to see.

  Also, some papers have been sized so that bleeding is less likely to occur when writing with aqueous ink. When recording is performed on paper that has been subjected to such size processing by an ink jet recording apparatus, the ink does not easily permeate into the paper, resulting in poor fixability of recorded images and characters. For this reason, when the user touches the recorded images and characters on the paper by hand, or when the recorded papers are sequentially stacked as in the case of continuous recording, the recorded images and characters may be blurred. Furthermore, if the ink fixing property is poor, bleeding has easily occurred at the boundary between the inks of different hues.

  As a method for solving these disadvantages, in addition to the above methods (1) to (7), one method is also proposed in Japanese Patent Application Laid-Open No. 6-143795. In this proposed method, the ink to be used is defined by the contact angle on the polytetrafluoroethylene (PTFE) surface. The contact angle of ink with respect to PTFE is greatly influenced by the surface roughness of PTFE. Further, when the present inventors investigated the relationship between the contact angle with respect to PTFE and the contact angle with respect to the actual recording medium, there is no correlation, and if the ink is defined only by the contact angle with respect to PTFE, the above inconvenience is solved. It turns out to be insufficient.

  Therefore, it is possible to effectively suppress bleeding and bleed by ink jet recording even on a recording medium called so-called plain paper, which is sized and paper fibers are exposed on the recording surface. An example is described next. A third embodiment of the ink jet recording apparatus according to the present invention will be described. In the third embodiment of the ink jet recording apparatus, the third embodiment of the ink jet recording method according to the present invention and the third embodiment of the ink and ink cartridge used in the ink jet recording apparatus and the ink jet recording method are used. Since the configurations of the ink jet recording apparatus and the ink cartridge can be the same as those shown in FIGS. 1 and 2, their illustration and description are omitted.

  In this embodiment, when recording is performed using two or more types of inks having different hues, at least one type has a difference in surface tension of 4 dyne / cm or more with respect to the other types of ink. The ink having the higher surface tension is used for recording line drawings such as characters, and the ink having the lower surface tension is used for recording general images (or plane images) such as graphics. As will be described later, the surface tension of the ink having the higher surface tension is preferably 49 dyne / cm or more, and the surface tension of the ink having the lower surface tension is preferably 45 dyne / cm or less.

  When recording line drawings such as characters, the present inventors have confirmed through experiments that even if ink with a large amount of blur is used, if the color difference from the recording medium is small, the blur is not noticeable and can withstand actual use. . In addition, since the ink used for recording characters is usually black ink, in this embodiment, two types of ink are usually used for line drawings such as characters and general images. The hue is limited to only a hue having a large color difference from a recording medium that is white or only to black. As a result, it is possible to reduce the type of ink and the number of heads, thereby simplifying the configuration of the ink jet recording apparatus and reducing the cost.

  In addition, as a result of studies including various subjective evaluations, the present inventors have confirmed by experiments that the recording quality is satisfactory when the amount of blurring of the line is 15 μm or less and the bleed amount is 200 μm or less. The bleeding amount is a jagged edge of the line. As shown in FIG. 29, the distance from the virtual line to each edge is measured by subdividing the edge of the line, and linear approximation is performed by the least square method so that the average of the distance (unevenness) is 0. The standard deviation σ of the unevenness amount was taken as the amount of bleeding.

  On the other hand, as shown in FIG. 30, the bleed amount is calculated by calculating the area where the ink protrudes from the boundary line between different hues, and dividing this area by the length of the boundary line. Evaluation was made based on the length of ink flow. This evaluation was performed because the bleed amount depends on the length of the boundary portion in the area.

  FIG. 31 is a diagram illustrating the relationship between the surface tension of ink and the amount of bleeding. FIG. 32 shows the relationship between the surface tension of the ink and the bleed amount. From FIG. 31, it was found that the surface tension needs to be 49 dyne / cm or more in order to make the amount of bleeding 15 μm or less. Furthermore, FIG. 32 shows that the surface tension needs to be 45 dyne / cm or less in order to make the bleed amount 200 μm or less.

  Black and yellow inks Ak and Ay having the same surface tension within the surface tension range, and black and yellow inks Bk and By having surface tensions different from the inks Ak and Ay within the surface tension range. FIG. 33 shows the evaluation results of performing recording and evaluating bleeding and bleeding. For evaluation, a 3-dot line drawing and a solid image were recorded. The line drawing was black and the solid bleed was the boundary between black and yellow, and the hue with the largest color difference was recorded. In FIG. 33, ◯ indicates that the amount of bleeding is 15 μm or less or the bleed amount is 200 μm or less, and X indicates that the amount of bleeding or bleed is other than these.

  As can be seen from FIG. 33, in the case of the inks Ak and Ay, the surface tension is 53 dyne / cm, the amount of bleeding is sufficiently small, but the amount of bleeding is large. On the other hand, in the case of the inks Bk and By, the surface tension is 33.6 dyne / cm, and the bleeding amount is sufficiently small but the bleeding amount is large. Accordingly, it was confirmed that the inks Ak and Ay are suitable for recording line drawings such as characters, and the inks Bk and By are suitable for recording general images.

  This embodiment is more effective as the color difference between the ink hue and the recording medium hue is larger. Usually, since the hue of the recording medium is white, the effect of this embodiment is greatest when the hue of the ink is black. Next, a description will be given of a fourth embodiment of the ink jet recording apparatus according to the present invention. In the fourth embodiment of the ink jet recording apparatus, the fourth embodiment of the ink jet recording method according to the present invention and the fourth embodiment of the ink and ink cartridge used in the ink jet recording apparatus and the ink jet recording method are used. Since the configurations of the ink jet recording apparatus and the ink cartridge can be the same as those shown in FIGS. 1 and 2, their illustration and description are omitted.

  As described above, it is effective to use highly permeable ink with a short fixing time in order to reduce bleeding. However, highly permeable ink is easy to bleed and is not suitable for recording characters and tables. On the other hand, it is effective to use an ink with low penetrability in order to suppress blur and perform high-quality recording. However, in this case, the fixing time becomes long and bleeding increases.

  Therefore, it is effective to reduce the bleed and blur by using different penetrating inks according to the type of image to be recorded. Everything will be different. For example, if you record an image with mixed characters and graphics, the recording density will differ for each ink used, so depending on the type of image to be recorded and the hue of the ink to be used, it may not be possible to perform high-quality recording There is also. The recording density (OD) indicates a density when recording at a printing rate of 100%. When recording is performed using black ink, it indicates an optical reflection density, and ink having a hue other than black is used. When used and recorded, it indicates the status A density.

  In this embodiment, two types of ink having the same hue but different permeability are used for at least one hue, and when recording an image in which different hue inks are not adjacent to each other on the recording medium, the lower permeability is used. Recording is performed using ink, and when recording an image in which inks of different hues are adjacent on a recording medium, recording is performed using the ink having the higher permeability. Further, the color material concentrations of the two types of ink (hereinafter referred to as color material concentrations) are set to different values so that the recording densities on the recording medium by the two types of inks are substantially the same. The color material includes a dye, a pigment, and the like.

  The present inventors conducted an experiment using a black dye as an ink dye and a plain paper Xerox 4024DP manufactured by Xerox Co., which is generally used for a recording medium, and obtained the following experimental results. First, in the first experiment Ex1, an image having a printing rate of 100% with respect to a recording medium using a low penetrability ink I1 and a high penetrability ink I2 each using a black dye having the same dye concentration. Was recorded. FIG. 34 is a diagram showing the dye concentrations of the inks I1 and I2 and the measured recording densities on the recording medium. As can be seen from the figure, when inks I1 and I2 having the same dye concentration are used, a large difference occurs in the recording density. In FIG. 34 and FIGS. 35 to 37 described later, the dye concentration is expressed in weight percent (wt%).

  On the other hand, in the second experiment Ex2, a low penetrability ink I3 and a high penetrability ink I4 using black dyes having different dye concentrations are used to record on the recording medium as in the experiment Ex1. On the other hand, an image with a printing rate of 100% was recorded. FIG. 35 is a diagram illustrating the color material densities of inks I3 and I4 and the measured recording densities on the recording medium. As can be seen from the figure, it was confirmed that when inks I3 and I4 having different dye concentrations were used, the recording densities were substantially the same. More specifically, by setting the color material density of the ink I3 having low permeability to be lower than the color material density of the ink I4 having high permeability, the recording density on the recording medium is set for the two types of inks I3 and I4. It can be substantially the same.

  Therefore, according to the present embodiment, bleeding and bleeding can be effectively and reliably suppressed. Generally, a color ink jet recording apparatus has four colors of ink of yellow, magenta, cyan, and black. However, since the hue of a recording medium is usually white, characters, tables, etc. are printed using yellow ink. It is very rare to record. Even if yellow ink is used to record characters, tables, etc. on a recording medium, the yellow ink bleed is hardly noticeable. For this reason, the effect of the present embodiment is larger as the color difference or brightness difference between two types of ink having the same hue and different permeability and the hue of the recording medium is larger, and the hue of the ink is black and the hue of the recording medium is white. The effect is the largest.

  In addition, the present inventors have examined the recording density at which a sufficiently high recording quality can be obtained by performing subjective evaluation or the like. When the recording medium is plain paper, the recording quality is 0.9 or more. Is within the allowable range, and if the recording medium is an inkjet recording paper dedicated for ink jet recording, the required value is higher than that for plain paper and the recording density is 1.3 or more, so that the recording medium is within the allowable range. I understood it. Further, in the case of image recording using two types of ink having the same hue and different penetrability, an allowable range is acceptable if the difference in recording density of each ink is about 0.3 or less regardless of the type of recording medium. It was also found that the recording quality of the inside can be obtained.

  Usually, when the difference in recording density is 0.3, it is detected as a very large difference to human eyes, but in this embodiment, two types of inks having different penetrability are used depending on the type of image. Therefore, the present inventors have found that the entire recorded image is not visible as a big difference. For example, when a character is recorded as a line drawing and a pattern with a printing rate of 100% is recorded as a general image such as a figure and the recording density on these recording media is compared, the difference in recording density is 0.3 or less. It was confirmed that the recording quality within the allowable range was obtained. The recording density of the ink used for recording the line drawing in this case on the recording medium is the recording density when a pattern having a printing rate of 100% is recorded using the ink.

  Next, a description will be given of a fifth embodiment of the ink jet recording apparatus according to the present invention. In the fifth embodiment of the ink jet recording apparatus, the fifth embodiment of the ink jet recording method according to the present invention and the fifth embodiment of the ink and ink cartridge used in the ink jet recording apparatus and the ink jet recording method are used. Since the configurations of the ink jet recording apparatus and the ink cartridge can be the same as those shown in FIGS. 1 and 2, their illustration and description are omitted.

  In this embodiment, two types of ink having the same hue but different permeability are used for at least one hue, and when recording an image in which different hue inks are not adjacent to each other on the recording medium, the lower permeability is used. Recording is performed using ink, and when recording an image in which inks of different hues are adjacent on a recording medium, recording is performed using the ink having the higher permeability. Furthermore, when recording is performed using ink having a lower recording density on the recording medium (in this case, ink having higher permeability), the recording is performed in a plurality of times.

  The present inventors conducted an experiment using a black dye as an ink dye and a plain paper Xerox 4024DP, which is generally used as a recording medium, and obtained the following experimental results. First, in the third experiment Ex3, a low-penetration ink I3 and a high-penetration ink I4 using black dyes having different dye concentrations are used, and the recording medium is tested similarly to the above-described experiment Ex2. An image having a printing rate of 100% was recorded, and recording using ink I4 having high permeability was performed a plurality of times by performing so-called overlap recording. FIG. 36 is a diagram showing the degree of overlap, which is the number of times of recording using ink I4, and the measured recording density on the recording medium. As can be seen from the figure, the recording density obtained by performing the recording using the ink I4 having a high dye density a plurality of times is substantially the same as the recording density obtained by the recording using the ink I3 having a low permeability. confirmed. More specifically, the recording density on the recording medium is set to two types of ink by performing the recording using the ink I4 having a high penetrability a plurality of times and performing the recording using the ink I3 having a low penetrability once. It can be made substantially the same about I3 and I4.

  Therefore, according to the present embodiment, bleeding and bleeding can be effectively and reliably suppressed. Generally, a color ink jet recording apparatus has four colors of ink of yellow, magenta, cyan, and black. However, since the hue of a recording medium is usually white, characters, tables, etc. are printed using yellow ink. It is very rare to record. Even if yellow ink is used to record characters, tables, etc. on a recording medium, the yellow ink bleed is hardly noticeable. For this reason, the effect of the present embodiment is larger as the color difference or brightness difference between two types of ink having the same hue and different permeability and the hue of the recording medium is larger, and the hue of the ink is black and the hue of the recording medium is white. The effect is the largest.

  Also in this embodiment, when the recording medium is plain paper, the recording quality is within the allowable range if the recording density is 0.9 or more, and when the recording medium is an inkjet recording paper dedicated for inkjet recording. Is within the allowable range if the recording density is 1.3 or more. Further, in the case of image recording using two types of ink having the same hue and different penetrability, an acceptable range is possible if the difference in recording density of each ink is about 0.3 or less, regardless of the type of recording medium. The recording quality can be obtained.

  Next, a modification of the fifth embodiment will be described. In the present modification, as in the fifth embodiment, two types of ink having the same hue and different penetrability are used for at least one hue, and an image in which different hue inks are not adjacent to each other on the recording medium is recorded. In some cases, recording is performed using the ink having the lower penetrability, and recording is performed using the ink having the higher penetrability when recording an image in which inks of different hues are adjacent on the recording medium. . When recording is performed using the ink having the lower recording density on the recording medium (in this case, the ink having the higher permeability), the recording is performed in a plurality of times. Further, as in the fourth embodiment, the color material densities of the two types of ink are set to different values so that the recording densities on the recording medium by the two types of ink are substantially the same.

  The present inventors conducted an experiment using a black dye as an ink dye and a plain paper Xerox 4024DP, which is generally used as a recording medium, and obtained the following experimental results. First, in the fourth experiment Ex4, a low-penetration ink I5 and a high-penetration ink I6 using black dyes having different dye concentrations are used, and the recording medium is tested similarly to the above-described experiment Ex2. An image having a printing rate of 100% was recorded, and recording using ink I6 having high penetrability was so-called multiple recording. FIG. 37 is a diagram showing the overlap that is the number of recordings using the ink I6 and the measured recording density on the recording medium. As can be seen from the figure, the recording density obtained by performing the recording using the ink I6 having a high dye concentration a plurality of times is substantially the same as the recording density obtained by the recording using the ink I5 having a low permeability. confirmed. More specifically, the recording using the highly penetrating ink I6 is performed a plurality of times, and the recording using the ink penetrating the ink I5 having a low permeability is performed once. It can be made substantially the same about I5 and I6.

  Therefore, according to this modification, bleed and blur can be effectively and reliably suppressed. Generally, a color ink jet recording apparatus has four colors of ink of yellow, magenta, cyan, and black. However, since the hue of a recording medium is usually white, characters, tables, etc. are printed using yellow ink. It is very rare to record. Even if yellow ink is used to record characters, tables, etc. on a recording medium, the yellow ink bleed is hardly noticeable. For this reason, the effect of the present embodiment is larger as the color difference or brightness difference between two types of ink having the same hue and different permeability and the hue of the recording medium is larger, and the hue of the ink is black and the hue of the recording medium is white. The effect is the largest.

  In this modification as well, when the recording medium is plain paper, the recording quality is within the allowable range if the recording density is 0.9 or more, and when the recording medium is an inkjet recording paper dedicated for inkjet recording. Is within the allowable range if the recording density is 1.3 or more. Further, in the case of image recording using two types of ink having the same hue and different penetrability, an acceptable range is possible if the difference in recording density of each ink is about 0.3 or less, regardless of the type of recording medium. The recording quality can be obtained.

  Next, a description will be given of a sixth embodiment of the ink jet recording apparatus according to the present invention. In the sixth embodiment of the ink jet recording apparatus, the sixth embodiment of the ink jet recording method according to the present invention and the sixth embodiment of the ink and ink cartridge used in the ink jet recording apparatus and the ink jet recording method are used. Since the configurations of the ink jet recording apparatus and the ink cartridge can be the same as those shown in FIGS. 1 and 2, their illustration and description are omitted.

  In this embodiment, when recording is performed using two or more types of inks having different hues, at least one type has a difference in contact angle with respect to the recording medium of 15 ° or more with respect to the other types of ink. The ink having a higher contact angle with respect to the recording medium is used for recording a line image such as a character, and the ink having a lower contact angle is used for recording a general image such as a figure. As will be described later, the contact angle of the ink with the higher contact angle is preferably 85 ° or more, and the contact angle of the ink with the lower contact angle is preferably 70 ° or less.

  FIG. 38 is a diagram illustrating the relationship between the contact angle of ink and the amount of bleeding. FIG. 39 shows the relationship between the ink contact angle and the bleed amount. From FIG. 38, it was found that the contact angle must be 85 ° or more in order to reduce the bleeding amount to 15 μm or less. Further, FIG. 39 indicates that the contact angle must be 70 ° or less in order to reduce the bleed amount to 200 μm or less.

  Black and yellow inks Ck and Cy having the same contact angle within the range of 85 ° or more of the contact angle, and black and yellow inks Dk and Dy having the same contact angle within the range of 70 ° of the contact angle. FIG. 40 shows an evaluation result obtained by performing recording using and and evaluating bleeding and bleeding. For evaluation, a 3-dot line drawing and a solid image were recorded. The line drawing was black and the solid bleed was the boundary between black and yellow, and the hue with the largest color difference was recorded. Furthermore, the contact angle of ink indicates that for plain paper Xerox 4024DP manufactured by Xerox Co., Ltd. as an example of plain paper as a recording medium. Since ink permeation occurs on the paper, the ink contact angle was measured immediately after the ink adhered to the plain paper Xerox 4024DP (after about 0.1 second). In the measurement itself, the moment when ink was deposited was photographed with a camera, and the contact angle was measured from the obtained still image. In FIG. 40, ◯ indicates that the bleeding amount is 15 μm or less or the bleed amount is 200 μm or less, and X indicates that the bleeding amount or bleed amount is other than these.

  As can be seen from FIG. 40, in the case of the inks Ck and Cy, the contact angle is 102 °, and the amount of bleeding is sufficiently small, but the amount of bleeding is large. On the other hand, in the case of the inks Dk and Dy, the contact angle is 51 ° and the bleed amount is sufficiently small, but the bleed amount is large. Accordingly, it was confirmed that the inks Ck and Cy are suitable for recording line drawings such as characters, and the inks Dk and Dy are suitable for recording general images.

  This embodiment is more effective as the color difference between the hue of the ink and the hue of the recording medium is larger. Normally, since the hue of the recording medium is white, the effect of this embodiment is effective when the hue of the ink is black. The biggest. For comparison, the inventors measured the contact angle with respect to PTFE using the same inks Ck, Cy, Dk, and Dy as described above. The measurement results are shown in FIG. From FIG. 41, it can be seen that the contact angles of the inks Dk and Dy are outside the range of contact angles defined in the above-mentioned Japanese Patent Application Laid-Open No. 6-143895. Compared with FIG. 40, the contact angles of the inks Ck and Cy shown in FIG. 41 are almost the same as those of FIG. 40, but the contact angles of the inks Dk and Dy shown in FIG. It has changed greatly. That is, it can be seen that the contact angle of the ink is much more correlated with the recording quality than the special material PTFE.

  Therefore, as in the method proposed in Japanese Patent Laid-Open No. 6-143895, the ink penetrability can be sufficiently defined by the contact angle between the surface tension of the ink and the PTFE not related to the recording medium. I found it impossible. Further, in the method proposed in the above Japanese Patent Laid-Open No. 6-143895, since the permeability of the ink is different, the character portion recorded mainly with the ink having a low permeability and the ink having a high permeability are recorded. Even if the image portion mainly has the same hue, there is a problem in that the recording density, saturation, brightness, etc. differ between the two, resulting in a decrease in recording quality. An embodiment that can solve this problem will be described below.

  A seventh embodiment of the ink jet recording apparatus according to the present invention will be described. In the seventh embodiment of the ink jet recording apparatus, the seventh embodiment of the ink jet recording method according to the present invention and the seventh embodiment of the ink and ink cartridge used in the ink jet recording apparatus and the ink jet recording method are used. Since the configurations of the ink jet recording apparatus and the ink cartridge can be the same as those shown in FIGS. 1 and 2, their illustration and description are omitted.

  Various studies have been made on the permeability between the ink and the recording medium based on the Lucas-Washburn equation. For example, Takuya Kadoya, “New Paper Science”, published by Chugai Industry Research Council, pp. It is going to be elucidated by 345-370, June 12, 1989. A test method for measuring permeability based on this theory is the Bristow test method. The absorption coefficient Ka (ml / (m 2 · ms 1/2)) obtained by the Bristow test method can uniquely represent the absorbability between the ink and the recording medium. Accordingly, when recording is performed with a combination of the recording medium and the ink having a small absorption coefficient Ka, the ink permeation into the recording medium is suppressed, and high-quality recording without blurring is possible.

  On the other hand, when recording is performed with a combination of the recording medium and the ink having a large absorption coefficient Ka, the penetration of the ink into the recording medium is promoted and the existence time of the ink on the recording medium is shortened. Quality recording is possible. Also, two ink groups having different absorption coefficients Ka to the recording medium are used, and general images are recorded mainly with a plurality of hues adjacent to the ink group having a large absorption coefficient Ka, and the ink group having a small absorption coefficient Ka. A line drawing such as a character is mainly recorded in which a plurality of hues are not adjacent to each other. This makes it possible to achieve both high-quality general image recording without bleeding at the color boundary portion and line drawing recording of sharp, high-quality characters and the like without blurring.

  Further, at least one pixel (dot) forming the color boundary portion is recorded with ink of an ink group having a large absorption coefficient Ka, and the other pixels are recorded with ink of the same hue of an ink group having a small absorption coefficient Ka. This makes it possible to achieve both high-quality general image recording without bleeding at the color boundary and line drawing recording of sharp, high-quality characters and the like without blurring, as well as uneven recording density and coloring on the recording medium. High quality recording with no difference in brightness and brightness can be performed.

  The inventors of the present invention examined the absorption coefficient Ka and the degree of bleeding of various black inks K′1 to K′5 by experiments, and obtained the results shown in FIG. The composition of the inks K′1 to K′5 is based on 2% by weight of an acidic dye and 5% by weight of diethylene glycol, 0 to 20.0% by weight of ethanol is added, and the remaining amount is water. The ethanol content of each of the inks K′1, K′2, K′3, K′4, and K′5 is 0, 5.0 wt%, 10.0 wt%, 15.0 wt%, and 20. 0% by weight. The unit of the absorption coefficient Ka is usually (ml / (m 2 · ms 1/2)), but in FIG. 42 and FIGS. 43 and 44 described later, the unit of the absorption coefficient Ka is (nl / (mm 2 · s 1/2) for convenience. )).

  Further, when the black, yellow, magenta, and cyan inks K6, Y6, M6, C6 to K9, Y9, M9, and C9 for color were examined by experiments, the absorption coefficient Ka and the degree of bleed for various recording media were examined by experiments. The following results were obtained. The compositions of the inks K6, Y6, M6, C6 to K9, Y9, M9, and C9 are based on 4% by weight of the direct dye and 5% by weight of glycerin, and 0 to 2.0% by weight of the nonionic surfactant is added. The remaining amount is water. The contents of the first nonionic surfactant in each of the inks K6, Y6, M6, C6, the inks K7, Y7, M7, C7, the inks K8, Y8, M8, C8 and the inks K9, Y9, M9, C9 are as follows. 0, 0.5 wt%, 1.0 wt% and 2.0 wt%.

  The inks K′1 to K′5 and the inks K6, Y6, M6, C6 to K9, Y9, M9, and C9 are measured in a sealed plastic container for each type of ink, and then bathed at 50 ° C. While stirring and dissolving for 3 hours, the solution was cooled to room temperature and filtered through a filter having a pore size of 0.2 μm. 42 and 43, the absorption coefficient Ka of each ink was obtained by performing a Bristow test using three types of copy quality paper as a recording medium. Furthermore, the degree of bleeding and bleeding was determined by recording on the above three types of copy quality paper at a resolution of 360 dpi.

  In FIG. 42, the degree of blur is evaluated in three stages. In the figure, the circles indicate that there are almost no blurs and sharp edges are realized, the triangles indicate that the edges are slightly blurred and the edges are slightly jagged, and the crosses indicate large blurs and uneven edges. It represents a remarkable state. The results shown in FIG. 42 indicate that the amount of ink ejected on each copy-quality paper is about 120 to 40 pl, which gives a perfect circle equivalent diameter of about 100 μm.

  From FIG. 42, the evaluation of the degree of bleeding is “Δ” for the combination of the ink having the absorption coefficient Ka of less than 15 and the recording medium, and the evaluation of the degree of bleeding is the combination of the ink having the absorption coefficient Ka of less than 10 and the recording medium. Was confirmed to be “◯”. On the other hand, in FIG. 43, the degree of bleeding is also evaluated in three stages. In the figure, ◯ indicates that the bleed is hardly visible and the color boundary is relatively clear, △ indicates that the bleed is slightly visible and the color boundary is slightly mixed, and X indicates that the large bleed is visible and color. This represents a state where the boundary portion cannot be recognized. The results shown in FIG. 43 indicate that the amount of ink ejected on each copy-quality paper is about 120 to 50 pl.

  From FIG. 43, the evaluation of the bleed degree is “Δ” for the combination of the ink having the absorption coefficient Ka of 50 or more and the recording medium, and the evaluation of the bleed degree is made for the combination of the ink having the absorption coefficient Ka of 89 or more and the recording medium. Was confirmed to be “◯”. FIG. 44 shows the experimental results obtained for the inks K10, Y10, M10, C10 to K15, Y15, M15, and C15 as in the case of FIG. Inks K10, Y10, M10, C10 to K12, Y12, M12, and C12 contain 2% by weight of the second to fourth nonionic surfactants instead of the first nonionic surfactant. . Further, the inks K13, Y13, M13, and C13 contain 1% by weight of a fifth nonionic surfactant in place of the first nonionic surfactant. Further, the inks K14, Y14, M14, and C14 are added with 15% by weight of ethanol in place of the first nonionic surfactant, and the inks K15, Y15, M15, and C15 are the first nonion. Instead of the system surfactant, 20% by weight of ethanol is added. The amount of ink ejected on each copy-quality paper was about 80 to 45 pl, and the bleed evaluation method was the same as in FIG.

  From FIG. 44, the evaluation of the bleed degree is “Δ” for the combination of the ink having the absorption coefficient Ka of 40 or more and the recording medium, and the evaluation of the bleed degree is made for the combination of the ink having the absorption coefficient Ka of 83 or more and the recording medium. Was confirmed to be “◯”. In this example, recording was performed using five types of inks, ink K′2 shown in FIG. 42 and inks K9, Y9, M9, and C9 shown in FIG. Black areas that do not touch the different hues such as yellow, magenta, and cyan were recorded with ink K'2, and the other areas were recorded with inks K9, Y9, M9, and C9. As a result, the line drawing of characters and the like recorded with the ink K'2 was free from blurring, and high-quality recording could be performed at a high recording density. At the same time, high-quality color recording without bleeding was performed at the color boundary portions in the general image recorded with the inks K9, Y9, M9, and C9.

  However, since inks having different characteristics are used, a new problem that the recording density of the black area recorded with the ink K′2 and the recording density of the black area recorded with the ink K9 appear to be different and the recording quality is somewhat deteriorated. Also occurred. Therefore, in this embodiment, it is desirable to record the black area at the boundary portion with the ink K9 for a predetermined recording width (for example, 2 dot width) and the other black area with the ink K′2. In this case, the recording density difference between the black areas is almost eliminated, and the deterioration of the recording quality can be prevented.

  As described above, the present embodiment is applied to black ink, which has a high chance of recording line drawings such as characters and the like, which has high demand for high quality without blurring, and yellow, magenta, and cyan inks that are basic colors for color recording. It is desirable to do. As the recording medium, it is desirable to use so-called plain paper such as copy paper that is most commonly used and paper fibers are exposed on the recording surface.

  By the way, in order to record a line image or a general image on a recording medium at a desired resolution in an inkjet recording apparatus, it is necessary to adjust the amount of ink ejected from the head so that dots having a size suitable for the desired resolution can be obtained. is there. Since the ink having low penetrability has a smaller dot spread on the recording medium than the ink having high penetrability, a larger amount of ink is recorded on the recording medium than the ink having high penetrability. This tendency is prominent in plain paper such as copy paper, bond paper, and postcards that have been subjected to processing such as a size that suppresses ink permeation as a recording medium. In contrast, ink-jet recording paper such as coated paper for exclusive use of ink-jet recording, overhead projector (OHP) film, and glossy paper has an ink receiving layer on the paper / film substrate, so that ink permeation is uniform. In addition, the ink penetration effect is relatively small because it is designed to speed up. The ink receiving layer is made of, for example, a hydrophilic / water-absorbing polymer such as polyvinyl alcohol or cationic resin, a resin, a pigment, a binder, or the like.

  As described above, since inks having different penetrabilities have greatly different properties on the recording medium, it is difficult to design a recording medium satisfying sufficient performance for each ink. Therefore, a method for adjusting the amount of ink ejected from the head according to the type and properties of the recording medium to be used has been proposed.

  Although the method of adjusting the amount of ink particles ejected from the head depending on the type of recording medium is effective, it is necessary to control the head driving conditions according to the ink particle ejection amount, and control of the head drive system Becomes complicated, and the configuration of the drive system of the head becomes complicated and expensive. In addition, depending on the driving conditions of the head, the ejection amount of ink particles may not be adjusted accurately.

  As a method for adjusting the ejection amount of ink particles, it has been proposed to adjust the diameter of dots by recording ink particles a plurality of times at the same position on a recording medium. For example, Japanese Patent Application No. 6-346552 is proposed. In the publication, an example is proposed in which inks having different permeability are used simultaneously. Specifically, when recording is performed using a highly penetrable color image recording ink using a dedicated recording medium adjusted for a low penetrability monochrome image recording ink. Ink particles of a high ink are recorded a plurality of times, and the dot diameter is adjusted to the same size as that of one ink particle of a low penetrability ink.

  However, ink with low penetrability enables high-quality recording even if the recording medium is plain paper, and does not require a recording medium adjusted exclusively for it. On the other hand, in the case of highly penetrating ink, bleeding does not occur even if the recording medium is plain paper, but when a line drawing of characters or the like is recorded, the peripheral portion of the line segment is blurred and an image with a clear outline is recorded. I can't. Therefore, a dedicated recording medium optimized for highly penetrable ink is desired in order to realize color image recording that requires color development, color reproducibility, and clarity.

  Thus, the necessity and requirement of a dedicated recording medium adjusted for ink with low permeability are low. On the other hand, the recording quality, such as saturation, hue, and color reproducibility, can be obtained even if the dot diameter is adjusted by recording ink particles several times during recording using highly penetrating ink. In general, it is lower than the recording quality when recording normally using a dedicated recording medium adjusted for high ink. Furthermore, when recording is performed using a low-permeability ink using a dedicated recording medium adjusted for high-permeability ink, it is necessary to reduce the amount of ink discharged, and overlap recording is performed. Can't do it.

  Therefore, normally, the recording medium characteristics including the spread of ink on the recording medium are adjusted for highly penetrable ink because of the requirement to realize clear and beautiful color image recording. For this reason, if recording is performed on such a dedicated recording medium adjusted for highly penetrable ink using low penetrability ink in the same manner as for plain paper, a large amount of ink is produced at one time. It will adhere to the recording medium. As a result, the amount of ink on the recording medium exceeds the ink absorption capacity of the ink receiving layer of the recording medium, the recorded characters are crushed, and the ink is condensed in the ink receiving layer, resulting in uneven recording density. There is a high possibility that Furthermore, since the amount of ink adhering to the recording medium is large, the drying and fixing time of the ink becomes long, and it is difficult to ensure the necessary ink drying and fixing time in consideration of the practical recording speed of the ink jet recording apparatus. The inconvenience of becoming easily occurs. In particular, the problem of uneven recording density and long fixing time during solid recording with a high recording density is a dense and uniform ink based on a transparent plastic film that does not absorb ink at all because it requires high light transmittance. It becomes prominent with an OHP film provided with a receiving layer.

  Accordingly, an eighth embodiment of the ink jet recording apparatus according to the present invention, which can prevent these problems more reliably even when the recording medium used is an OHP film or the like, will be described below. In the eighth embodiment of the ink jet recording apparatus, the ink cartridge shown in FIG. 2 can be used, and the eighth embodiment of the ink jet recording method according to the present invention is used. The configuration of the ink jet recording apparatus can be the same as that shown in FIG. 1, and therefore its illustration and description are omitted.

  In this embodiment, when recording is performed on a recording medium dedicated to inkjet recording such as an OHP film using ink with low permeability, the amount of ink attached to the recording medium during one head scan is reduced. This prevents a large amount of ink from adhering to the recording medium almost simultaneously. Specifically, when the average recording ink amount per unit area by one head scanning is recorded on the recording medium using highly penetrating ink, it is attached to the recording medium by one head scanning. Set to the same level as the predetermined ink amount. That is, when recording on a recording medium using ink with low penetrability, the amount of ink attached to the recording medium during one head scan is set to be equal to or less than the ink absorption capacity of the recording medium. Further, by repeating the scanning of the head at the time of recording using such low penetrability ink, the ink amount per unit area of the low penetrability ink adhering to the recording medium can be reduced to the predetermined ink amount. And approximately the same level. In this embodiment, the evaporation property of the ink solvent is also used so that the amount of ink adhering to the recording medium during one head scan does not exceed the ink absorbing ability of the recording medium, so that unevenness in recording density is reduced. At the same time, it is possible to ensure the time necessary for drying and fixing the ink.

  In the case of this embodiment, the composition of the black ink stored in the ink cartridge 11-5 shown in FIG. 2 is, for example, 2% by weight of acidic black dye, 5% by weight of diethylene glycol, 5% by weight of ethanol, and remaining water. is there. On the other hand, the composition of black, yellow, magenta and cyan inks stored in the ink cartridges 11-1 to 11-4 is, for example, 3% by weight of direct dyes of each color, 10% by weight of diethylene glycol, and nonionic surfactant 1 5% by weight and remaining water. The inks of these compositions were obtained by weighing each type of ink in a sealed plastic container, stirring and dissolving for 3 hours while bathing at 50 ° C., cooling to room temperature, and filtering with a filter having a pore size of 0.2 μm. . When the permeability of each ink is indicated by the absorption coefficient Ka of the Bristow test (J.TAPPI paper pulp test method No. 51) for copy paper Xerox 4024DP, the black ink with low permeability in the ink cartridge 11-5 is about 9 nl. / (Mm 2 · s 1/2), the highly penetrating black, yellow, magenta and cyan inks in the ink cartridges 11-1 to 11-4 are about 110 to 150 nl / (mm 2 · s 1/2), respectively. It was.

  FIG. 45 is a diagram showing the relationship between the amount of ink attached to the recording medium and the dot diameter when recording is performed on the recording medium using black ink with low permeability in the ink cartridge 11-5. . In the figure, the vertical axis indicates the dot diameter, and the horizontal axis indicates the ink amount. Characteristics Ia, IIa, IIIa, and IVa indicate cases where the first, second, and third copy sheets and the OHP film are used as recording media, respectively. The dot diameter indicates the average value of the true circle diameter when the area of 50 dots recorded on the recording medium is measured and each dot is regarded as a true circle.

  FIG. 46 is a diagram showing the relationship between the amount of ink attached to the recording medium and the dot diameter when recording is performed on the recording medium using black ink having high permeability in the ink cartridge 11-1. It is. In the figure, the vertical axis indicates the dot diameter, and the horizontal axis indicates the ink amount. The characteristics Ib, IIb, IIIb and IVb show the cases where the first, second and third copy papers and the OHP film are used as recording media, respectively. As in the case of FIG. 45, the dot diameter indicates the average value of the true circle diameter when the area of 50 dots recorded on the recording medium is measured and each dot is regarded as a true circle. In addition, when recording is performed on a recording medium using yellow, magenta, and cyan inks having high penetrability in the ink cartridges 11-2 to 11-4, the amount of ink attached to the recording medium and the dot diameter Since the relationships are similar to those in FIG. 46, their illustration is omitted.

  A predetermined dot diameter suitable for recording at a resolution of 360 dpi using these inks is about 110 ± a little larger than 100 μm = √2 × 25.4 mm / 360, in which diagonally adjacent dots are connected to form a diagonal line. When the thickness is 10 μm, the amount of ink for obtaining a predetermined dot diameter on plain paper such as the first to third copy papers is about 100 pl for the low penetrability ink and about 50 pl for the high penetrability ink. It was. When dots were recorded on an inkjet recording paper such as an OHP film with such an ink amount and the diameter thereof was measured, in the case of ink with low penetrability, although the dot diameter is slightly larger than the predetermined dot diameter, In the case of highly penetrating ink, a predetermined dot diameter, that is, an optimum value was obtained.

  When the present inventors performed recording on plain paper using these inks under these conditions, high-quality monochrome (black) recording without bleeding could be performed, and high-quality color recording without bleeding was possible. It was confirmed that it could be done. In addition, when recording was performed on an OHP film using these inks under the same conditions, it was confirmed that high-quality color recording was possible, but recording was particularly performed in the case of monochrome (black) recording. It was confirmed that the unevenness of the recording density due to the agglomeration of ink becomes remarkable in the solid recording portion having a high density.

  Therefore, the present inventors applied this embodiment to scan 360 dpi solid recording twice using a black ink with low penetrability by a head portion having 48 nozzles in an OHP film. This was performed by recording various patterns, and was compared with Comparative Example Ce1 in which 48 dots per line were solid-recorded by one scan of the head portion. The scanning time for the head portion was set to about 1 second. As a result, in Comparative Example Ce1, the recording density was uneven due to the aggregation of the ink, and the recording quality was low. On the other hand, in the case of experiment ex1 in which the one-dot placement line pattern in the horizontal direction as shown in FIG. 47 and the reverse pattern shown in FIG. 48 are overlapped and recorded by scanning the head part twice, the ink is compared with the comparative example Ce1. It was confirmed that the unevenness of the recording density due to the agglomeration could be greatly reduced and the recording quality was remarkably improved. Similarly, in the case of the experiment ex2 in which the checkered pattern as shown in FIG. 49 and the inverted pattern shown in FIG. 50 are overlapped and recorded by scanning the head part twice, the recording density unevenness due to the aggregation of the ink is larger than in the comparative example Ce1. It can be confirmed that the recording quality can be greatly improved and the recording quality is remarkably improved. Furthermore, in another comparative example Ce2, the waiting time until the next scanning is started after one scanning of the head unit is set to about 1 second, and the recording time of the head unit of 2 times as a whole is set. One row and 48 dots were solid-recorded so as to be equivalent to the cases of experiments ex1 and ex2 in which overlapping recording by scanning was performed, but the result was the same as in the case of Comparative Example Ce1, and the recording density was uneven due to ink aggregation. The recording quality was low.

  Furthermore, the present inventors also confirmed the recorded results when the experiments ex1 and ex2 were combined. In the experiment ex3, a one-dot line pattern as shown in FIG. 47 and a checkered pattern as shown in FIG. 49 are overlapped and recorded by two successive scannings of the head portion, and in the horizontal direction as shown in FIG. The inverted pattern of the one-dot placement line pattern and the inverted pattern of the checkered pattern as shown in FIG. 50 were overlapped and recorded by the next two successive head scannings. In the case of this experiment ex3, it was confirmed that the recording density unevenness due to the aggregation of the ink can be greatly reduced and the recording quality is remarkably improved as compared with the comparative example Ce1. In the experiment ex4, the checkered pattern as shown in FIG. 49 and the inverted pattern shown in FIG. 50 are overlapped and recorded by two successive scannings of the head part, and the one-dot placement line pattern as shown in FIG. The inversion pattern shown in FIG. 48 was recorded by being overlapped by the next two successive head scans. In the case of this experiment ex4, since a pattern in which dots are not adjacent to each other is preferentially recorded, the recording density unevenness due to the aggregation of ink can be significantly reduced compared to the experiment ex3, and the recording quality is further improved as compared with the comparative example Ce1. I was able to confirm.

  In addition, when a head portion having 48 nozzles was used and four nozzles were scanned a total of 12 times, a solid recording of 48 dots wide corresponding to one normal scan was performed on an OHP film. It was confirmed that the unevenness of the image quality could be greatly reduced and the recording quality was improved. In this way, it was confirmed that the recording density can be reduced more effectively and sufficient drying / fixing time can be secured by reducing the number of dots to be recorded in one scan and increasing the number of scans. .

  For example, when an image is recorded by the same method as in the experiment ex4, an AND (logical product) of the image data input from the host device or the like to the inkjet recording device and the checkered pattern shown in FIG. The head unit is controlled based on the above, and the head unit is controlled based on the AND of the image data and the reverse pattern of the checkered pattern shown in FIG. The head unit is controlled based on the AND of the image data and the line pattern shown in FIG. 47 during the third scan of the head unit, and the image data and the reverse pattern of the line pattern shown in FIG. 48 are used during the fourth scan. The head unit is controlled based on AND.

  Further, when the image is recorded by the same method as the experiment ex4, the input image data corresponding to the AND of the image data and the checkered pattern shown in FIG. Input to the apparatus, and input image data corresponding to AND of the image data and the reverse pattern of the checkered pattern shown in FIG. 50 may be input to the ink jet recording apparatus at the second scanning. In this case, the input image data corresponding to the AND of the image data and the line pattern shown in FIG. 47 is directly input to the inkjet recording apparatus at the third scanning of the head unit, and the image data is Input image data corresponding to AND with the reverse pattern of the line pattern shown in FIG. 48 is input to the inkjet recording apparatus.

  As described above, in this embodiment, when recording is performed using a low permeability ink on a recording medium whose recording characteristics are adjusted with respect to a highly permeable ink, per head area per unit area. When performing sequential recording by setting the amount of ink to be recorded to be equal to or less than the amount of ink to be recorded in one scan using highly penetrable ink and by scanning the head portion a plurality of times using ink having low penetrability In the case of solid recording, a plurality of complementary thinning patterns are recorded, and in the case of recording image data, AND between a plurality of complementary thinning patterns and image data is recorded. In this case, the thinning pattern is not limited to the line pattern and the checkered pattern, and for example, a pair of symmetrical thinning patterns may be used. In addition, it is possible to perform recording sequentially using a plurality of pairs of symmetrical thinning patterns. In this case, it is desirable to perform overlapping recording in a priority order in a pattern in which dots are not adjacent to each other. Further, when the maximum recording width in the direction perpendicular to the scanning direction that can be recorded by a head unit having a plurality of nozzles that eject ink with low penetrability in one scan is D dots, the D dot width by this head unit The image data may be decomposed into N pieces of data having a dot width of less than D dots, and the decomposed image data may be sequentially recorded on the recording medium by N scans.

  The present embodiment is particularly suitable when an OHP film is used as a recording medium, but an OHP film having a double structure can also be used as the OHP film. The double-structure OHP film has different characteristics on the front and back sides. In other words, the first OHP film designed for highly penetrating ink and the second OHP film designed for low penetrating ink are bonded together, so the table shows high-quality color. It is suitable for recording images, and the back side is suitable for recording monochrome images with no uneven recording density. The inventors of the present invention performed recording as described above on the OHP film having such a double structure. For example, the thickness of the ink receiving layer of the second OHP film is set to about 1 of that of the first OHP film. When set to .5 times, it is confirmed that high-quality color images can be recorded on the first OHP film in the table, and monochrome images without uneven recording density can be recorded on the back second OHP film. did it.

  For the OHP film used in this example, various water-soluble, water-absorbing or various polymers imparted with these characteristics can be used. Furthermore, in order to adjust the characteristics, an appropriate amount of various insoluble polymers and inorganic pigments such as clay, talc, alumina, silica and the like can be added. However, in the case of an OHP film, it is necessary not to disturb transparency. As the polymer, polyvinyl alcohol, gelatin, albumin, casein, cationic starch, gum arabic, polyamide, polyvirnipyrrolidone, water-soluble cellulose and the like can be used.

  The ink receiving layer provided on the recording medium such as OHP may be formed on the recording medium in advance or may be formed at the time of recording. A method of performing recording while forming an ink receiving layer on a recording medium is known. For example, JP-A 63-299939, JP-A 5-96720, JP-A 6-23973, and JP-A 6-92010. The method disclosed in the Gazette and the like can be adopted.

  By the way, since the diameter of the nozzle of the head is as small as 30 μm to 100 μm, for example, a non-volatile and highly hygroscopic solvent (so as not to cause clogging due to evaporation and drying of ink at the nozzle tip (nozzle orifice)) ( Solvent) is added to the ink. However, even if the clogging due to the deposition of the dye in the nozzle orifice can be prevented, the thickening of the ink due to the evaporation of the solvent is inevitable. As the ink viscosity increases, the ink ejection direction becomes undefined, causing a positional deviation of dots recorded on the recording medium, and in an extreme case, the ink cannot be ejected, resulting in missing dots. Therefore, the back-up unit 46 as shown in FIG. 1 is used to suppress variations in ink ejection from the nozzles due to ink thickening. Specifically, ink that has been thickened is sprayed (sprayed) from all the nozzles to the backup unit 46 so that the viscosity of the ink does not exceed a certain level. However, the degree of thickening of ink varies depending on the type and concentration of components such as a wetting agent and a dye contained in the ink, and may vary among multiple types of ink used in the same inkjet recording apparatus. Nevertheless, conventionally, no consideration was given to the degree of thickening that differs between inks.

  Therefore, when the degree of thickening differs among various types of ink used in the same ink jet recording apparatus, it is conceivable to perform nozzle spraying corresponding to each ink. However, in this case, it is necessary to frequently spray the nozzles, which causes the inconvenience that the ink consumption increases and the recording speed becomes slow. It is also conceivable to spray the nozzles according to the ink having the greatest degree of thickening, but in this case as well, there is a disadvantage that the ink consumption is relatively large and the recording speed cannot be improved to some extent. .

  Next, a ninth embodiment of the ink jet recording apparatus according to the present invention capable of eliminating these disadvantages will be described below. In the ninth embodiment of the ink jet recording apparatus, the ink cartridge shown in FIG. 2 can be used, and the ninth embodiment of the ink jet recording method according to the present invention is used. The configuration of the ink jet recording apparatus can be the same as that shown in FIG. 1, and therefore its illustration and description are omitted.

  In this embodiment, for two or more types of inks used in the same ink jet recording apparatus, the thickening of the ink by solvent evaporation is set to the same level. As a result, the spraying conditions of the nozzles can be suppressed to a minimum because the thickening of two or more types of inks is comparable, so that the recording speed can be improved and the ink consumption can also be suppressed. Is possible.

  As a solvent for the ink, water and a mixture of water and a water-soluble organic solvent are used. Examples of organic solvents include monohydric alcohols such as methanol, ethanol, (normal) propyl alcohol, and isopropyl alcohol, dihydric alcohols such as ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, diethylene glycol, and triethylene glycol, and glycerin. Polyalkylene glycols such as trihydric alcohol, polyethylene glycol and polybutylene glycol, nitrogen-containing heterocyclic compounds such as N-methyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone, ethylene glycol monomethyl ether, diethylene glycol Lower alkyl ethers of polyhydric alcohols such as monomethyl ether and triethylene glycol monomethyl ether can be used.

  The content of the organic solvent in the ink is 5 to 80% by weight, preferably 5 to 50% by weight. This is because when the content of the organic solvent is less than 5% by weight, drying of the ink becomes faster or the solubility of the dye is lowered, and the dye in the ink is likely to be deposited and easily clogged. On the other hand, if it exceeds 80% by weight, the viscosity of the ink increases and it becomes difficult to eject the ink from the nozzles of the head.

  The basic composition of the ink used in this example is as described above, but other dispersants, cationic surfactants, anionic surfactants, nonionic surfactants, polyvinyl alcohol, celluloses, and water-soluble resins as necessary. Needless to say, a viscosity adjusting agent such as diethanolamine or triethanolamine may be added.

  The inventors measured the degree of thickening of an ink having the following composition by experiment.

  Ink IK1: Black dye 8% + Diethylene glycol 5% + Additive 2% + Residual water ink IK2: Black dye 8% + Diethylene glycol 15% + Additive 2% + Residual water ink IK3: Black dye 4% + Diethylene glycol 5% + Ethanol 6% + Residual water ink IK4: Color dye (Acid Blue 9) 3% + Diethylene glycol 10% + Ethanol 3% + Additive 2% + Residual water When the surface area is Smm 2, 42 g (≈42000 mm 3, specific gravity about 1.04) is separately put in four petri dishes having a radius r = 36.6 mm and a depth h = 20 mm so that V / S≈10 mm is satisfied. The solvent was evaporated by leaving it at room temperature and normal humidity (25 ° C., 60% RH). Further, the remaining ink was well stirred every certain time (24 hours), and the viscosity of each ink was measured from the first day to the twelfth day with an E-type viscometer.

  As a result, it was confirmed that the viscosity of each ink increased as time passed as shown in FIG. In the figure, the vertical axis represents viscosity and the horizontal axis represents time. The ink IK1 is indicated by a circle, the ink IK2 is indicated by a square, the ink IK3 is indicated by an x, and the ink IK4 is indicated by a +. As can be seen from FIG. 51, no thickening occurred in any of the inks until the fourth day, but the thickening was noticeable after the fifth day. Further, the inks IK2 to IK4 each showed the same change in viscosity of 1000 cp or less, whereas the ink IK1 was confirmed to have an extremely increased viscosity.

  The inventors of the present invention expanded the vertical axis of FIG. 51 and examined the thickened state of each ink in more detail, and the results shown in FIG. 52 were obtained. In FIG. 52, the same symbols as in FIG. 51 are used for the inks IK1 to IK4. Further, using these results, recording was actually performed using each of the inks IK1 to IK4, and the influence of the thickening of the ink was examined.

  By using the ink jet recording apparatus described in conjunction with FIG. 1 and FIG. 2, (i) the nozzle spray is sprayed once every 20 seconds by the combination of ink IK1 and ink IK4 having a viscosity difference of 200 cp or more after the fifth day. (Ii) Continuous recording while spraying the nozzles once every 20 seconds with a combination of ink IK2 and ink IK4 having a viscosity difference of 200 cp or more after the 10th day , (Iii) Continuous recording is performed while spraying the nozzles once every 20 seconds using a combination of ink IK3 and ink IK4 having a viscosity difference of 200 cp or more after the seventh day. Inspected for defects. As a result, it was confirmed that a recording failure such as missing dots occurred in the case of the ink combination (i), and no recording failure occurred in the case of the combination of (ii) and (iii). .

  Further, the composition of the yellow, magenta, cyan, and black inks Y0, M0, C0, and K0 is adjusted as follows so that the increase in ink viscosity is the same as shown in FIG. When continuous recording was performed while spraying nozzles once per second, it was also confirmed that good recording could be performed without causing defective recording such as missing dots or dot displacement. In FIG. 53, the vertical axis represents the viscosity measured under the same conditions as described above, and the horizontal axis represents time. The yellow ink Y0 is indicated by a circle, the magenta ink M0 is indicated by an x mark, the cyan ink C0 is indicated by a + mark, and the black ink K0 is indicated by a Δ mark.

  Yellow ink Y0: yellow dye 2% + diethylene glycol 10% + ethanol 3% + additive 2% + regulator 2% + residual water magenta ink M0: red dye 4% + diethylene glycol 10% + ethanol 3% + additive 2% + regulator 1% + residual water cyan ink C0: blue dye 3% + diethylene glycol 10% + ethanol 3% + additive 2% + residual water black ink K0: black dye 6% + diethylene glycol 10% + addition Therefore, when ink jet recording is performed using ink of at least two colors or more, the ink viscosity is increased by evaporation of the solvent of each ink, that is, the degree of thickening is set to the same level. It was confirmed that normal recording can be continued even under the spray conditions where the spraying is performed a minimum number of times. The increase in ink viscosity due to ink solvent evaporation is, for example, by placing 42 g of each ink separately in a petri dish with a radius r = 36.6 mm and a depth h = 20 mm and leaving it at room temperature and normal humidity (25 ° C. and 60% RH). It was also confirmed that the difference in viscosity on the fifth day when the solvent was evaporated was about 1000 cp or less, preferably within about 200 cp. Furthermore, it was confirmed that each ink may be an aqueous ink containing a dye and an organic solvent, an ink in which a pigment is dispersed, or the like.

  In this embodiment, the composition of the ink is adjusted so that the thickening of each ink is approximately the same. However, as a modification of this embodiment, according to the frequency of use of the nozzles of the head that ejects each ink. Thus, the composition of each ink may be adjusted so that the difference in viscosity between the inks always falls within a certain range.

  That is, in order to perform high-quality and high-speed recording in an inkjet recording apparatus, it is one method to set the number of nozzles of the head to be used according to the type of image to be recorded. In this case, when recording line drawings such as characters, a large number of nozzles are used for recording as fast as possible, and when recording color general images such as graphics, a small number of nozzles are used for high recording. Since the recording of quality is performed, the nozzles of each head are not used uniformly, and the non-use time (standby time) of the nozzles differs depending on each head. For example, if the number of nozzles of a small number of heads when recording a general image is m = 16 and the number of nozzles of a large number of heads when recording a line image is n = 128, the recording time of the general image is a line drawing. The recording time is about n / m = 8 times. Therefore, in this modification, the ratio of the increase in the viscosity of ink supplied to the head having a small number of nozzles is about 8 times the ratio of the increase in the viscosity of ink supplied to a head having a large number of nozzles. By adjusting the composition of the ink, the same effect as described above can be obtained.

  In order to set the ink thickening ratio to the same level, it is possible to use methods such as (a) adjusting the dye concentration, (b) adjusting the solvent concentration, and (c) adjusting the additive concentration. It is. In the case of the method (a), there is a possibility that the recording density is lowered. In the case of the methods (a) and (c), there is a possibility that the initial ink viscosity is increased and the fixing time is extended. . However, according to the experimental results of the present inventors, it has been confirmed that the degree of thickening of the ink can be adjusted within a range where there is no problem even when any of the above methods (a) to (c) is adopted.

  In each of the above embodiments, the number of types of ink to be used, the composition of the ink, the characteristics of the recording medium, etc. are not limited to those described above, and it is possible to combine various inks and recording media. Needless to say. Furthermore, a plurality of embodiments and / or modifications may be appropriately combined depending on the application.

  As mentioned above, although this invention was demonstrated by the Example, this invention is not limited to these Examples, A various deformation | transformation and improvement are possible within the scope of the present invention.

1 is a perspective view showing a main part of a first embodiment of an ink jet recording apparatus. It is a perspective view which shows a head part. It is a figure which expands and shows typically the photograph of the recording result at the time of recording a character on the quality paper for a copy with the resolution of 360 dpi using two types of ink. It is a figure which expands and shows typically the state of the bleed in the photograph of the recording result in the case of recording the image which consists of yellow and black. It is a figure which expands and shows typically the photograph of the recording result at the time of recording using the black ink which adjusted dye. The bleed state in the photograph of the recording result when recording with black ink having high permeability at the boundary portion x between the yellow area Y and the black area B on the recording medium having the first ink permeability It is a figure which expands and shows typically. The bleed state in the photograph of the recording result when recording with black ink having high permeability at the boundary portion x between the red region R and the black region B on the recording medium having the first value of ink permeability It is a figure which expands and shows typically. The bleed state in the photograph of the recording result when recording with the black ink having high permeability at the boundary portion x between the yellow area Y and the black area B on the recording medium having the ink permeability of the second value It is a figure which expands and shows typically. The bleed state in the photograph of the recording result when recording with black ink having high permeability at the boundary portion x between the red area R and the black area B on the recording medium having the second ink permeability It is a figure which expands and shows typically. It is a figure explaining the state of a bleed according to the brightness (contrast) difference of an adjacent area | region. It is a figure explaining the state of a bleed | bread at the time of recording by changing the permeability | transmittance of the highly permeable ink used in the boundary part of an adjacent area | region. It is a figure explaining the dependence of the recording order of the state of a bleed in a boundary part at the time of recording by the black ink of two types of high and low penetrability, and the ink of another hue with high permeability. It is a figure explaining the bleed state in the boundary part at the time of changing the recording order by the black ink of different permeability | transmittance. It is a figure explaining the state of the back surface of a recording medium at the time of changing the recording order by the different permeable black ink. It is a figure explaining the bleed state in the boundary part at the time of changing the recording order by the black ink of different permeability | transmittance. It is a figure which shows the result of a Bristow test about the ink with high permeability, and the ink with low permeability. It is a figure which shows the recording result at the time of recording on the recording medium with comparatively high ink permeability. 1 is a block diagram illustrating an image data processing system in a first embodiment of an ink jet recording apparatus. FIG. It is a figure which shows the dot recording position of image data. 6 is a flowchart illustrating operations of a black data boundary color determination unit, a black data separation unit, and a dot control unit when the recording width of black ink having high penetrability at a boundary portion is 1 dot. 6 is a flowchart illustrating operations of a black data boundary color determination unit, a black data separation unit, and a dot control unit when the recording width of black ink having high permeability at the boundary portion is p dots. Boundary color discriminating unit for black data, black data separating unit, and dot control unit for adjusting the recording width for recording with black ink having high permeability at the color boundary part according to the lightness difference between hues of adjacent regions It is a flowchart which shows this operation | movement. Black data boundary color discriminating unit, black data separating unit, and dot control when adjusting the recording width for recording with black ink having high permeability at the color boundary part according to the amount of ink that records adjacent areas It is a flowchart which shows operation | movement of a part. Operation of black data boundary color discrimination unit, black data separation unit and dot control unit when calculating the recording area recorded with black ink with high penetrability and the recording area recorded with black ink with low penetrability It is a flowchart which shows. It is a figure which shows the bleed which generate | occur | produces in the boundary part which a solid recording area of a certain color and a solid recording area of another color adjoin. FIG. 26 is a diagram schematically showing the bleed in FIG. 25. It is a figure which shows the relationship between the difference of Rf value, and the grade of a bleed. It is a figure which shows the relationship between the contact time of an ink, and the osmosis | permeation amount. It is a figure explaining the amount of bleeding. It is a figure explaining the amount of bleed. It is a figure which shows the relationship between the surface tension of an ink, and the amount of bleeding. It is a figure which shows the relationship between the surface tension of an ink, and a bleed amount. It is a figure which shows the evaluation result of a bleed and bleeding. It is a figure which shows the experimental result at the time of recording an image with a printing rate of 100% using the ink with low permeability | transmittance using the black dye which has the same dye density | concentration, respectively, and ink with high permeability | transmittance. It is a figure which shows the experimental result at the time of recording an image with a printing rate of 100% using the ink with low permeability | transmittance using the black dye which has mutually different dye density | concentration, and ink with high permeability | transmittance. It is a figure which shows the experimental result at the time of recording several times using an ink with high permeability | transmittance. When recording an image with a printing rate of 100% using a low penetrability ink and a high penetrability ink using black dyes having different dye concentrations, recording using the penetrable ink multiple times. It is a figure which shows the experimental result at the time of performing. It is a figure which shows the relationship between the contact angle of ink, and the amount of bleeding. It is a figure which shows the relationship between the contact angle of ink, and the amount of bleed. It is a figure which shows the evaluation result of a bleed and bleeding. It is a figure which shows the measurement result of the contact angle with respect to PTFE of ink Ck, Cy, Dk, Dy. It is a figure which shows the absorption coefficient Ka with respect to various recording media, and the degree of a blur. It is a figure which shows the absorption coefficient Ka with respect to various recording media, and the grade of a bleed. It is a figure which shows the absorption coefficient Ka with respect to various recording media, and the grade of a bleed. FIG. 5 is a diagram illustrating a relationship between an amount of ink attached to a recording medium and a dot diameter when recording is performed on the recording medium using black ink with low penetrability. FIG. 6 is a diagram illustrating a relationship between an amount of ink attached to a recording medium and a dot diameter when recording is performed on the recording medium using black ink having high penetrability. It is a figure which shows a line pattern. It is a figure which shows the inversion pattern of a line pattern. It is a figure which shows a checkered pattern. It is a figure which shows the inversion pattern of a checkered pattern. It is a figure which shows the viscosity increase with respect to the time of various inks. It is a figure which expands and shows a part of FIG. It is a figure which shows the thickening with respect to the time of the ink of 4 colors.

Explanation of symbols

5-1 to 5-5 Removable levers 11-1 to 11-5 Ink cartridge 20 Black data boundary color determination unit 21 Black data separation unit 22 Dot control unit 23 Drive unit 25 CPU
26 Memory 40 Inkjet recording device 41 Frame 42 Carrier 43 Stage shaft 44 Paper feed roller 45 Head unit 46 Backup unit 47 Motor 48 Belt 51 Housing 51
52 slots

Claims (6)

In an ink jet recording method in which a color image is recorded on a recording medium using ink of at least two hues, the difference in increase in ink viscosity due to solvent evaporation of each ink is defined as Vmm ³ for the ink volume to be released and Smm for the open area. when a ^2, as V / S = 10 mm is satisfied, is set to each ink so that within 1000cp when 5 days open left at the normal temperature and humidity is 25 ° C. 60% RH, ink jet recording method .   2. A color image is recorded on the recording medium by using the inks of two or more hues by a head portion composed of heads having different numbers of nozzles, and the degree of thickening of each ink is adjusted according to the number of nozzles. The inkjet recording method as described. When the number of nozzles of the first head of the head unit is m and the number of nozzles of the second head is n, the degree of thickening of the ink supplied to the first head is the ink supplied to the second head. The inkjet recording method according to claim 2, wherein the viscosity is set to n 2 / m times the degree of thickening. In an ink jet recording apparatus that records a color image on a recording medium using ink of at least two or more hues, the difference in increase in ink viscosity due to solvent evaporation of each ink indicates that the volume of ink to be released is Vmm ³ , and the open area is Smm . ^2. Inkjet recording apparatus set to be within 1000 cp when each ink is left open at room temperature and humidity of 25 ° C. and 60% RH for 5 days so that V / S = 10 mm is satisfied. .   A means for recording a color image on the recording medium using the inks of two or more hues by a head portion composed of heads having different numbers of nozzles, and adjusting the degree of thickening of each ink according to the number of nozzles; The ink jet recording apparatus according to claim 4. When the number of nozzles of the first head of the head unit is m and the number of nozzles of the second head is n, the degree of thickening of the ink supplied to the first head is the ink supplied to the second head. The ink jet recording apparatus according to claim 5, wherein the viscosity is set to n 2 / m times the degree of viscosity increase.

Images