JP4484505B2 - Inkjet recording system, determination apparatus and program - Google Patents

Description

  The present invention relates to an ink jet recording system that includes both a dye ink containing a dye as a colorant and a pigment ink containing a pigment, and performs recording using both the dye recording agent and the pigment recording agent on the same recording medium. The present invention relates to a determination device and a program.

  In a color ink jet recording apparatus, a dye or a pigment can be used as a coloring material contained in a recording agent (hereinafter also simply referred to as ink). However, the dye ink using a dye as a color material and the pigment ink using a pigment as a color material differed in terms of the color developability, the state of penetration into the recording medium, and the handling such as an appropriate recovery process for the recording head. Often in a situation. Therefore, conventionally, when a dye is used as the coloring material, a dye ink is applied to all colors, and when a pigment is used, a configuration in which the pigment ink is applied to all colors is generally used.

  However, in the image quality required in the market, for objects such as characters and figures, high-density, clear and high-contrast quality is required, whereas natural images recorded in full color are required. For color images, there is a demand for image quality that produces natural coloring even when colors are mixed without blurring. Therefore, in order to achieve the image quality required in recent years, an ink jet recording apparatus is also provided that applies pigment ink to black ink, while applying dye ink to color inks such as cyan, magenta, and yellow. Yes. Also, a recording apparatus and a recording method having such a configuration have already been disclosed in, for example, Patent Document 1.

  According to Patent Document 1, a method of applying each ink to various recording media in a configuration in which a pigment is used as a color material for black ink and a dye is used as a color material for color ink is disclosed. According to this document, a recording method that is different for each recording medium is described so that the characteristics of the pigment ink appear appropriately. For example, for a recording medium having a glossy surface, other color inks are used. At the same time, black ink is not used, and recording is performed using black ink only in the gray scale mode. This is because when the black pigment ink is recorded simultaneously with the dye color ink, only the portion where the pigment ink is recorded becomes a non-glossy part, and the non-glossy part is locally scattered, resulting in an uncomfortable image. It is explained from.

  Furthermore, there is disclosed a concern that a transparent plastic sheet such as an OHP sheet may be cracked by pigment ink. Accordingly, a black recording method is disclosed in which cyan, magenta, and yellow are combined with a pigment black at a suitable ratio in order to obtain a black image having a higher density while not causing cracks.

JP 2000-198227 A

  However, in recent years, there has been an increasing demand for photographic images having high image quality, glossiness, and rich color developability comparable to silver salt photographs, and the recording method described in Patent Document 1 alone cannot adequately cope with it. Is coming. In other words, in a situation where a black image with a higher density is required while using a glossy recording medium, the density of the conventional black forming method in which color inks of dyes are mixed and expressed is insufficient. It will be regarded as an image with poor Rihari.

  The present invention has been made to solve the above-mentioned problems, and the object of the present invention is to use glossy paper while being able to record a high-density image using an ink having a pigment as a coloring material. Another object of the present invention is to provide an ink jet recording system, a determination device, and a program that can form a color image without losing glossiness even in such a recording medium.

Therefore, in the present invention, a first recording mode capable of recording an image by applying a pigment ink containing a pigment and a dye ink containing a dye to a first recording medium having gloss, In the ink jet recording system capable of executing a second recording mode capable of recording an image by applying the pigment ink and the dye ink to a second recording medium having no gloss, The maximum amount of the pigment ink applied to the area of the predetermined area of the first recording medium in the recording mode is not 0, and the predetermined area of the second recording medium in the second recording mode Less than the maximum amount of the pigment ink applied to the region.

Another aspect of the present invention is a first recording mode capable of recording an image by applying a pigment ink containing a pigment and a dye ink containing a dye to a first recording medium having gloss. A second recording mode capable of recording an image by applying the pigment ink and the dye ink to a non-glossy second recording medium, and the pigment ink and the dye A determination device for determining an ink application amount, wherein when applying the first recording mode, the pigment ink and the dye ink are applied according to an image to be recorded on the first recording medium. A first deciding means for deciding the amount; and a second deciding amount of the pigment ink and the dye ink according to an image to be recorded on the second recording medium when the second recording mode is executed. 2 decision A means, the maximum application amount per unit area of the pigment ink can be determined by the first determination means, not 0, and per unit area of the pigment ink can be determined by the second determining means It is characterized by being less than the maximum amount given.

Furthermore, the present invention provides a first recording mode in which an image can be recorded by applying a pigment ink containing a pigment and a dye ink containing a dye to a first recording medium having gloss. And causing the computer to execute a process for executing the second recording mode in which the pigment ink and the dye ink are applied to the second glossy recording medium to record an image. In the program, the processing determines the application amount of the pigment ink and the dye ink according to an image to be recorded on the first recording medium when executing the first recording mode. A first determining step and a second determining step of determining the application amount of the pigment ink and the dye ink in accordance with an image to be recorded on the second recording medium when executing the second recording mode. Seen, the maximum application amount per unit area of the pigment ink can be determined by the first determining step, not 0, and the maximum application amount per unit area of the pigment ink can be determined by the second determining step It is also characterized by few.

  According to the present invention, since the recording amount of the pigment ink is suitably suppressed in a glossy recording medium, it is possible to realize an image that takes advantage of the high density peculiar to the pigment to the extent that the glossiness of the recording medium is not impaired. it can.

Embodiments of the present invention will be described below.
FIG. 1 is a block diagram for explaining a control configuration of an ink jet recording system applicable to this embodiment. The ink jet recording system according to the present embodiment includes an image processing apparatus and an ink jet recording apparatus (hereinafter also simply referred to as a recording apparatus).

  In the figure, reference numeral 101 denotes a recording apparatus main control unit for controlling the entire recording apparatus, and is constituted by an MPU, a ROM, a RAM, and the like. Reference numeral 102 denotes a recording buffer, which can store image data before being transferred to the recording head 103 as raster data. The recording head 103 is an ink jet recording head having a plurality of recording elements capable of ejecting ink droplets, and ejects ink from each recording element in accordance with image data stored in the recording buffer 102. Reference numeral 104 denotes a paper supply / discharge motor control unit that controls conveyance of the recording medium and paper supply / discharge. Reference numeral 105 denotes an interface (I / F) for exchanging data signals with the image processing apparatus. Reference numeral 113 denotes an I / F signal line for connecting the two. As the type of the I / F signal line 113, for example, a specification of Centronics can be applied. A data buffer 106 temporarily stores image data received from the image processing apparatus. Reference numeral 107 denotes a system bus for connecting each function of the recording apparatus.

  On the other hand, reference numeral 108 denotes an image processing apparatus main control unit which mainly controls image creation and image data control in the image processing apparatus, and is composed of an MPU, ROM, RAM, and the like. Reference numeral 109 denotes an interface (I / F) for exchanging data signals with the recording apparatus. Reference numeral 110 denotes a display unit for displaying various information to the user. For example, a CRT can be applied. Reference numeral 111 denotes an operation unit for a user to perform an operation. For example, a keyboard or a mouse can be applied. A system bus 112 connects the image processing apparatus main control unit 108 and each function.

  FIG. 2 is a diagram for explaining image data processing performed by the recording system of the present embodiment. FIG. 2A is a flowchart showing each step of image processing, and FIG. 2B is a schematic diagram for explaining the form of image data in each step.

  In FIG. 2A, when image data is input, color correction is first performed in step S201. In the color correction, 8-bit luminance data represented by R (red), G (green), and B (blue) is corrected and converted into RGB 8-bit luminance data. The signal value can be converted by referring to a lookup table (LUT) stored in advance in the memory.

  In step S202, the converted RGB 8-bit luminance data is decomposed into 4-bit 8-bit density data of C (cyan), M (magenta), Y (yellow), and K (black). At this stage, a gray image for four planes (four colors) is generated. The four-color separation can be performed by a method such as referring to a look-up table (LUT) stored in advance in the memory as in the case of color correction.

  In step S203, the 4-bit separated 8-bit density data is subjected to multilevel error diffusion processing for each plane, and the 4-color 8-bit density signal is converted into a 4-color 3-bit density signal.

  In the subsequent step S204, a binarization process called an index expansion process is performed and converted into binary data that can be recorded by the recording head for each plane, that is, for each color.

  FIG. 3 is a diagram for explaining the index expansion process. It is assumed that the 3-bit image data output from the multi-level error diffusion process has five gradation values from gradation 0 to 4 as shown in the figure. One pixel having such a gradation value corresponds to a 2 × 2 area shown in the pattern of the figure, and each area is an area in which one dot of the recording head can be recorded. Show.

  When the gradation value is 0, no dot is recorded in the 2 × 2 area. The output signal for indicating this state is “0000”, and the image data indicating the gradation value 0 is converted to “0000” by the index expansion performed in step S204.

  When the gradation value is 1, one dot is recorded in the 2 × 2 area. At this time, the output signal differs depending on where in the 2 × 2 four areas the dots are recorded. That is, when the gradation value that is the input value is 1, four types of output signals are output according to some rules.

  Similarly, two kinds of output signals are prepared for gradation value 2 and four kinds of output signals are provided for gradation value 3, and one kind of “1111” is output for gradation value 4. It is a signal.

  These plural types of index patterns can be arranged sequentially, or can be arranged randomly in order to reduce the texture generated by arranging them sequentially. When it is desired to have randomness in the order of arrangement, for example, a configuration in which an output value is randomly selected from a plurality of signal values by preparing a random number generator or the like may be employed.

  Note that the relationship between the index pattern and the output signal for each gradation value is not limited to the content described with reference to FIG. The arrangement order of the index patterns may be different for each color, and the relationship between the gradation value and the pattern may be different. Further, in the above description, the description has been made with the configuration in which the gradation value of 5 steps is represented by the 3-bit density signal. However, the present invention is not limited to this value. The number of gradations may be different.

  Further, each process shown in each step of FIG. 2 is processed in the ink jet recording system of this embodiment. Up to which process is performed by the image processing apparatus, and after which process is performed by the recording apparatus. The clear division of, is not particularly defined. However, in consideration of processing load and speed, it can be said that a configuration in which the image processing apparatus performs up to multi-level error diffusion and the index expansion is performed by the recording apparatus is preferable. In this case, the memory of the recording apparatus main control unit 101 stores a plurality of index patterns as shown in FIG.

  Next, a recording method on a glossy recording medium, which is the most characteristic part of the present invention, will be described in comparison with recording methods on other general recording media. In the present specification, the glossy recording medium refers to all the recording media that are glossy in an unrecorded state on the recording surface on the ink recording side, and in particular, a recording medium called “glossy paper” It is not limited to. A recording medium prepared exclusively for the applied inkjet recording system may be used, or a recording medium having a glossy surface, which is commercially available for general purposes. In addition, the substrate that supports the ink receiving layer may be made of paper or a plastic film.

  FIG. 4A shows a recording rate of each color ink when forming a 100% black image in recording on a general recording medium, and FIG. 4B shows a gray gradation recording. FIG. 6 is a diagram showing the recording rate of each color ink at each gradation when performing the above. The recording rate in this specification is defined as the ratio of the area where dots are actually recorded to the total area within a predetermined area where a predetermined ink color can be recorded.

  According to FIG. 4A, when an image of 100% black is formed, the black recording rate is 100%, and the other CMY recording rates are 5%, for a total recording rate of 115%. Yes.

  Further, according to FIG. 4B, in the low gradation area, the black ink is not applied, and a gray image is formed with only three colors of CMY. As the gradation increases, the recording rate of CMY ink increases to almost the same rate, but when the gray gradation value reaches approximately 50%, black ink recording starts, and at the same time, the recording rate of CMY ink gradually increases. It is reduced. At a certain point in time, the recording rates of the two are reversed, and an image is formed in a region called substantially black with the black ink dominant.

  With respect to such a relationship of the recording rate, better gradation can be obtained by using only black as a pigment ink. That is, at a low gradation, it is possible to express a smooth gray by recording three color inks having relatively low densities in a balanced manner. On the other hand, at high gradations, the characteristics of the pigment ink that excels at color development at a higher density can be used effectively.

  However, when recording is performed on a glossy recording medium at such a recording rate, the glossiness of the recording surface is impaired at high gray levels. When the black ink is mixed with other areas where no recording is performed, a sense of incongruity due to the difference in texture is sensed.

  FIG. 5A is a diagram showing the recording rate of each color ink on a glossy recording medium when forming a 100% black image in the present embodiment, and FIG. 5B shows a gray gradation. FIG. 6 is a diagram illustrating a recording rate of each color ink at each gradation when recording. In FIG. 5B, the gradation for starting the black ink recording is almost the same as in FIG. 4B, but the increase in the recording rate thereafter is moderate, and the recording rate of the color ink is also shown. It is not reduced as much as in the case of 4 (b). The recording rate when forming a final black 100% image is 50% of the same rate for each color as shown in FIG.

  Thus, suppressing the recording rate of black ink and simultaneously increasing the recording rate of other color inks can reduce the influence of pigments that have an effect of impairing gloss. Further, by recording more color inks, it is possible to suppress the decrease in black density due to the black ink reduction as much as possible. Furthermore, unlike the recording on glossy paper disclosed in Patent Document 1, the black ink is not recorded at all, so that the effect specific to the pigment is exhibited and a clear black image can be obtained.

  Pigment inks have the disadvantage of “degrading the glossiness of a glossy recording medium”, but also have the advantage of “high density color development” that is particularly required for black images. According to the present invention, it is possible to keep the disadvantages as inconspicuous as much as possible while taking advantage of the pigment ink by keeping a good balance of the recording ratio with other color inks.

  FIG. 6 is a flowchart for explaining a series of image processing performed by the ink jet recording system of the present embodiment in order to realize the recording ratio of each color described above.

  When the user inputs a command for recording an image created from various applications, first, in step S601, image data to be recorded is input from the various applications. At this time, the type of the recording medium selected by the user is described in the header of the image data, and the type of the recording medium to be recorded can be determined by analyzing the header.

  In step S602, it is determined whether the determined recording medium is a glossy recording medium. At this time, if it is determined that the recording medium is not glossy, the process proceeds to step S605.

  On the other hand, if it is determined that the recording medium is glossy, the process proceeds to step S603, where the index pattern is read from the area where the normal index pattern is stored to the area where the index pattern for glossy paper is stored. Switch to and set. Further, in step S604, the black parameters used in the multilevel error diffusion described in step S203 of FIG. 2 are switched and set so as to correspond to the index pattern after the switching.

  FIG. 7 is a diagram showing the gradation values from 0 to 2 and the index patterns corresponding to the respective gradation values set in Steps S603 and S604. As shown in the figure, in this embodiment, in order to realize the recording rate shown in FIG. 5, the gradation value output by multi-level error diffusion is suppressed to 2 which is half of the normal value, and the recording after index expansion is performed. The recording rate on the medium is set so as not to exceed 50% at the maximum.

  Returning again to FIG. In step S605, image data conversion processing is performed according to the flowchart described in FIG. At this time, in the image data processing performed in step S201 and step S202, black can be converted on the premise of a recording rate of 100% as in the case of other colors. Even if conversion similar to that for other colors is performed, the actual recording rate of black can be suppressed to 50% at the maximum because of the limitation in the index expansion described above.

  When the series of image processing ends, the process proceeds to step S606, and the binarized image data is transmitted to the recording head 103 and recording is performed. In addition, the index data reading area and the multi-value error diffusion parameters switched in steps S603 and S604 are switched to default again in step S607.

  As described above, according to the present embodiment, when a black image is formed on a glossy recording medium using a black ink using a pigment as a color material and a color ink using a dye as a color material, the black ink is used. And color ink at a suitable recording rate, a high-quality color image without loss of glossiness can be output while realizing a high-density black image. Further, according to the present embodiment, since a method of reducing the black recording rate by using index expansion is adopted, it is possible to suppress a bit drop or the like when converting image data.

(Other embodiments)
In the above embodiment, the black recording rate is reduced to 50% and the color recording rate is increased to 50%. However, the recording rate of the present invention is limited to such a rate. is not. The recording rate of each color shown in FIG. 5 is merely an example, and the recording rate of each color is determined at a suitable rate, even if it is in other proportions or different rates for each color of the color ink. If the effect is obtained, the present invention is effective.

  In the above embodiment, the method of reducing the gradation value input to the index development has been described in order to suppress the black ink recording rate. However, the method of controlling the recording rate is not limited to this method. Absent. For example, among the steps shown in FIG. 2, a method of limiting the maximum black tone value in the process of the four-color separation shown in step S202 may be used. However, in this case, it is desirable that sufficient bit accuracy is ensured when developing black data.

  In the above, the maximum recording rate of black is limited to prevent the glossiness of the recording medium from being lost. However, the parameter that actually affects the glossiness is not the recording rate itself but the unit. In other words, it is the amount (volume) of black ink recorded per area. Therefore, if the discharge amount per drop can be reduced by half while keeping the recording rate constant, the same effect as the above embodiment can be obtained, and even when such a method is adopted. It does not depart from the scope of the present invention.

  Further, in a serial type ink jet recording apparatus, in general, an image is formed by a plurality of recording scans on the same image area in order to reduce variation between a plurality of recording elements and a connecting stripe between recording scans. In many cases, so-called multi-pass recording is employed. In this case, in each printing scan, printing is performed while thinning print data using a plurality of complementary multi-pass masks. In the present invention, this multi-pass mask is used to increase the black ink printing rate. It is also possible to reduce. That is, a black multi-pass mask for recording on glossy paper is prepared separately from the normal one, and the black multi-pass mask has a recording rate of 50%, for example, in a state of complementing each other. If it is made a simple structure, the effect of the present invention can be obtained.

  Furthermore, in the above description, the ink containing pigment is black, and the ink containing cyan is magenta and yellow as the ink containing dye. For example, the present invention is limited to such ink color combinations. It is not what is done. The ink containing a pigment as a coloring material may be cyan, magenta, or the like other than black, or a combination thereof. Furthermore, the types of inks to be applied are not limited to these four colors, and it is effective to use light cyan or light magenta having a lower colorant density together with the inks.

  In the above embodiment, the multi-value error diffusion method is used to quantize the multi-value density data into several levels of density data. However, the present invention is limited to such a configuration. not. For example, even if a quantization method using a dither pattern is employed, the effect of the present invention is effectively exhibited as long as quantization is performed from multi-value density data to several levels of density data.

  Regardless of which method is used, by setting the ink amount per unit area of the pigment ink recorded on the glossy recording medium to be smaller than the ink amount when recording on the non-glossy recording medium, high density If the glossiness of the recording medium can be prevented as much as possible while realizing a black image, the present invention is effective.

  In the present invention, a software program that realizes the functions of the above-described embodiments is directly or remotely supplied to a system or apparatus, and the computer of the system or apparatus reads and executes the supplied program code. Including the case where it is also achieved by.

Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. That is, the present invention includes a computer program itself for realizing the functional processing of the present invention. In this case, the program may be in any form as long as it has a program function, such as an object code, a program executed by an interpreter, or script data supplied to the OS.
As a recording medium for supplying the program, for example, flexible disk, hard disk, optical disk, magneto-optical disk, MO, CD-ROM, CD-R, CD-RW, magnetic tape, nonvolatile memory card, ROM, DVD (DVD-ROM, DVD-R).

  As another program supply method, a client computer browser is used to connect to an Internet homepage, and the computer program of the present invention itself or a compressed file including an automatic installation function is downloaded from the homepage to a recording medium such as a hard disk. Can also be supplied. It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer is also included in the scope of the present invention.

  In addition, the program of the present invention is encrypted, stored in a storage medium such as a CD-ROM, distributed to users, and key information for decryption is downloaded from a homepage via the Internet to users who have cleared predetermined conditions. It is also possible to execute the encrypted program by using the key information and install the program on a computer.

  In addition to the functions of the above-described embodiments being realized by the computer executing the read program, the OS running on the computer based on an instruction of the program is a part of the actual processing. Alternatively, the functions of the above-described embodiment can be realized by performing all of them and performing the processing.

  Furthermore, after the program read from the recording medium is written to a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion board or The CPU or the like provided in the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are also realized by the processing.

It is a block diagram for demonstrating the structure of control of the inkjet recording system applicable to embodiment of this invention. (A) And (b) is a figure for demonstrating the image data processing in embodiment of this invention. It is a figure for demonstrating an index expansion process. (A) And (b) is the figure which showed the recording rate of each color ink at the time of forming a black image in the recording with respect to a general recording medium. (A) And (b) is the figure which showed the recording rate of each color ink at the time of forming a black image in the recording with respect to a glossy recording medium. 6 is a flowchart for explaining a series of image processing performed by the inkjet recording system applicable in the embodiment of the present invention. It is the figure which showed the index pattern corresponding to the gradation value from 0 to 2, and each gradation value.

Explanation of symbols

101 Recording Device Main Control Unit 102 Recording Buffer 103 Recording Head 104 Feed / Discharge Motor 105 Recording Device I / F
106 Data Buffer 107 System Bus 108 Image Processing Device Main Control Unit 109 Image Processing Device I / F
110 Display Unit 111 Operation Unit 112 System Bus 113 I / F Signal Line

Claims (5)

A first recording mode capable of recording an image by applying a pigment ink containing a pigment and a dye ink containing a dye to a first recording medium having gloss, and a second recording without gloss In an ink jet recording system capable of performing a second recording mode capable of recording an image by applying the pigment ink and the dye ink to a medium,
The maximum amount of the pigment ink applied to the area of the predetermined area of the first recording medium in the first recording mode is not 0, and the second recording medium in the second recording mode The inkjet recording system is less than a maximum amount of the pigment ink applied to the region of the predetermined area.   The amount of the dye ink applied to the region where the amount of the pigment ink applied becomes the maximum in the first recording mode is the amount of the pigment ink applied to the region where the amount of the pigment ink is maximized in the second recording mode. 2. The ink jet recording system according to claim 1, wherein the amount of the dye ink applied to a region is larger than the amount of the dye ink.   The pigment ink includes a black ink containing a black pigment, and the dye ink includes a cyan ink containing a cyan dye, a magenta ink containing a magenta dye, and a yellow ink containing a yellow dye. The inkjet recording system according to claim 1 or 2. A first recording mode capable of recording an image by applying a pigment ink containing a pigment and a dye ink containing a dye to a first recording medium having gloss, and a second recording without gloss A second recording mode in which an image can be recorded by applying the pigment ink and the dye ink to a medium, and determining the application amount of the pigment ink and the dye ink A determination device of
First determination means for determining the amount of the pigment ink and the dye ink applied in accordance with an image to be recorded on the first recording medium when executing the first recording mode;
Second determination means for determining the amount of the pigment ink and the dye ink applied in accordance with an image to be recorded on the second recording medium when executing the second recording mode;
Have
The maximum application amount per unit area of the pigment ink that can be determined by the first determination unit is not 0, and is smaller than the maximum application amount per unit area of the pigment ink that can be determined by the second determination unit A determination device characterized by that. A first recording mode capable of recording an image by applying a pigment ink containing a pigment and a dye ink containing a dye to a first recording medium having gloss, and a second recording without gloss A program for causing a computer to execute a process for executing a second recording mode in which an image can be recorded by applying the pigment ink and the dye ink to a medium,
The processing includes a first determination step of determining the application amount of the pigment ink and the dye ink according to an image to be recorded on the first recording medium when executing the first recording mode; A second determining step of determining the application amount of the pigment ink and the dye ink according to an image to be recorded on the second recording medium when executing the second recording mode;
The maximum application amount per unit area of the pigment ink that can be determined by the first determination step is not 0, and is smaller than the maximum application amount per unit area of the pigment ink that can be determined by the second determination step. A program characterized by that.