JP2014141041A - Image forming device and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of performing reproduction of high fluorescent color visibility when a mixed image of a normal color image and a fluorescent image is printed on a printing medium.SOLUTION: An image forming device includes a reception section for receiving color image data including a fluorescent color, a first image data generation section for generating image data for printing using a color material visible on a recording medium by visible light irradiation, a second image data generation section for generating image data for printing using a first fluorescent ink having first emission intensity by ultraviolet irradiation, a third image data generation section for printing using a second fluorescent ink having emission intensity higher than the first emission intensity by the ultraviolet irradiation, and a printing section for applying the first fluorescent ink around an area not coated with any visible coloring material on the recording medium, and applying the second fluorescent ink around an area coated with a visible coloring material on the recording medium.

Description

  Embodiments described herein relate generally to an image forming apparatus capable of reproducing a fluorescent color with high visibility and an image processing method thereof.

In order to reproduce an image in which a fluorescent color image is mixed with a normal color image, there is printing that uses a fluorescent ink that can be visually recognized when irradiated with excitation light in addition to the process ink of each color (CMYK).
However, when the process ink image and the fluorescent ink image are simply overlapped and printed, the fluorescent image cannot be visually recognized even when the overlapping portion of the two types of ink is irradiated with excitation light.

  Therefore, it is possible to confirm the light emission due to the excitation light irradiation by recording more fluorescent inks on the overlapping part with the process ink image, but the printed part of the overlapping part with the process ink is corrugated or printed on the printing medium. Ink blurring causes image quality degradation.

In order to eliminate the above-described waviness of the printing medium and ink bleeding, for example, a method of fixing the total amount of the fluorescent ink and the process ink and relatively reducing the fluorescent ink can be considered.
However, this method also suppresses the light emission of the fluorescent ink, so that it does not ensure the visibility of the fluorescent image.

JP 2005-7590 A

  The problem to be solved by the present invention is to provide an image forming apparatus capable of reproducing with high visibility of a fluorescent color when a mixed image of a normal color image and a fluorescent image is printed on a printing medium. .

  In order to achieve the above object, an image forming apparatus according to the present invention uses a receiving unit that receives color image data including a fluorescent color, and a color material that can be viewed on a recording medium by visible light irradiation from the color image data. A first image data generation unit that generates image data for printing, and image data for printing using the first fluorescent ink having the first emission intensity by ultraviolet irradiation from the color image data A second image data generating unit that generates the first image data generated by the first image data generating unit recorded at the same position on the first image data; and the first image data generated by the ultraviolet irradiation from the color image data. Generation of first image data in which image data to be printed using a second fluorescent ink having a light emission intensity higher than the light emission intensity is recorded at the same position on the recording medium And applying the first fluorescent ink around a region where the color material that can be visually recognized on the recording medium is not applied. A printing unit that applies the second fluorescent ink around a region where a color material that can be visually recognized on the recording medium is applied.

1 is a configuration diagram of an image forming apparatus according to an embodiment. The block diagram which shows the structure of each color image data generation part. The figure which shows typically superposition | stacking of a process ink and fluorescent ink. The figure which shows the spectral characteristic of two types of fluorescent ink. The flowchart which shows the process of each color image data generation part. The figure which shows the conversion curve used for process ink data. The figure which shows the conversion curve used for fluorescent ink data. FIG. 4 is a schematic diagram for explaining the operation of an inkjet head. The figure for demonstrating the printing area | region of process ink and two types of fluorescent ink. The figure which shows the conversion table used for fluorescent ink data.

(First embodiment)
Hereinafter, embodiments will be described with reference to FIGS. 1 to 9.

  Hereinafter, embodiments in which the present invention is applied to a color multifunction peripheral will be described. FIG. 1 schematically shows a general system configuration related to an MFP (multifunction peripheral) using an inkjet image forming apparatus.

  The multifunction device 100 includes a main control unit 101, a scanner unit 102, a printer unit 103, and an operation panel 104.

  A shared bus 111 shown in FIG. 1 connects a CPU (Central Processing Unit) or the like of each unit to be described later, whereby program I / O transfer via the CPU, or a peripheral device controls the bus as a bus master, and directly memory, etc. Data transfer by a bus master accessing the network is possible.

  The main control unit 101 includes a main CPU 110, a storage unit 112, an image processing unit 116, a page memory control unit 117, and a page memory 118.

  The main CPU 110 controls the entire main control unit 101.

  The storage unit 112 performs bidirectional communication between the main CPU 110 and a printer CPU 130 of the printer unit 103 described later, and stores a control program and various data for the main CPU 110. The storage unit 112 is an aggregate of a read-only memory (hereinafter referred to as ROM) and a rewritable memory (hereinafter referred to as RAM). Stores data that is generated or changed by.

  The image processing unit 116 processes an image input from the scanner unit 102 or the client terminal described later. The page memory control unit 117 stores or reads out image information in the page memory 118. The page memory 118 has an area where image information for a plurality of pages can be stored, and is formed so that data obtained by compressing image information from the scanner unit 102 can be stored for each page.

  The operation panel 104 includes various operation keys 141, a liquid crystal display unit 142 having soft keys (touch panel), and a panel CPU 140 to which these are connected, and a user performs an operation for changing parameters, which will be described later. Panel CPU 140 is connected to main CPU 110. Various commands are input from the operation keys 141 or the soft keys of the liquid crystal display unit 142 and transmitted from the panel CPU 140 to the main CPU 110.

  A scanner unit 102, which is an image reading unit, is connected to the main CPU 110, and under the control of the scanner unit 120, controls the scanner unit 102. A CCD driver 123 that drives a line sensor such as a CCD; a scanning motor driver 124 that controls the rotation of a scanning motor that moves a carriage (not shown) carrying a line sensor, an exposure lamp, a mirror, and the like; an image recognition unit 125; And an image correction unit 126.

  The printer unit 103 illustrated in FIG. 1 has, for example, a conventionally known configuration, and includes a printer CPU 130, a storage unit 132, an inkjet engine 133, a head unit control unit 134, a conveyance control unit 135, and a process control unit 136. The well-known configuration described below is not shown.

The printer CPU 130 is connected to the main CPU 110 and controls the entire printer unit 103 under the control of the printer CPU 130.
The storage unit 132 stores a control program and various data.
The ink jet engine uses, for example, an element (piezo element) that is deformed by applying a voltage, the ink storage space in the head is increased / decreased by the deformation, and ink droplets are ejected by this pressure. The configuration for ejecting ink droplets is not limited to this, and other known methods can also be used.

  The head unit control unit 134 drives a head unit having a plurality of nozzles, and controls landing points in the main scanning direction.

  The conveyance control unit 135 controls drive motors of various rollers to control conveyance of a recording medium accommodated in a known paper cassette from the paper cassette along the paper conveyance path.

The process control unit 136 controls a known pressurizer, head unit control unit, and conveyance control unit, and adjusts the color and amount of ink according to the image data of each color ink including two types of input fluorescent ink. .

  Hereinafter, the flow of image processing including fluorescent color processing will be described.

  When an image data transmission start signal is received from an external terminal such as a personal computer (hereinafter referred to as PC) via an interface (hereinafter referred to as I / F) (not shown), an image is captured into the page memory 118. The color ink image data and fluorescence image data created by photo retouching software or the like are received via the I / F, and are respectively stored in the first image area and the second image area in the RAM constituting the storage unit 112. Stores colored image data and fluorescent image data for one page. This data includes the size of the image.

  After completion of the image processing image capturing process, the main CPU 110 calculates fluorescent ink data according to the data flow shown in FIG.

  Image data of color inks CMYK (Cyan, Magenta, Yellow, Black) and image data of fluorescent color F are supplied from an external terminal 201 such as a PC. A signal based on additive color mixing of RGB may be given instead of the color ink CMYK, but in order to simplify the explanation, a case where it is given with the color ink CMYK will be described below as an example. The image data Df of the fluorescent color F is given as a binary value represented by 0 or 1, or a multivalue represented by 0 to 255 or the like.

  CMYK color image data and fluorescent color data Df supplied from the external terminal 201 are supplied to the first image data generation unit 202 and supplied to the first printing unit. Each color ink amount data Ic, Im, Iy, Ik Get. Further, the respective ink amount data Ic, Im, Iy, and Ik are supplied to the second image data generation unit 203 and the third image data generation unit 204, and the first fluorescent ink F1 and the second fluorescent ink F2 are supplied. The ink amount data If1 and If2 of each ink are obtained.

  In the example of FIG. 2, an example in which the ink amount data If1 and If2 of each ink of the first fluorescent ink F1 and the second fluorescent ink F2 is obtained in parallel is shown, but the ink amount of the first fluorescent ink F1 is shown. After obtaining the data If1, the ink amount data If2 of the second fluorescent ink F2 may be obtained.

  FIG. 3 is a diagram schematically showing the superposition of ink. FIG. 4 shows the spectral characteristics of two types of fluorescent inks having different emission intensities. As is apparent from FIG. 4, the emission intensity V2 of the second fluorescent ink is stronger than the emission intensity V1 of the first fluorescent ink. In the present embodiment, as shown in FIG. 3, the first and second fluorescent inks are used to superimpose the second fluorescent ink F2 having high emission intensity on the CMYK inks of the respective colors and apply the CMYK ink. The first fluorescent ink F1 having a weak emission intensity is applied to the non-pixel.

  Fluorescent ink data corresponding to the image data amount of each color ink CMYK is calculated according to the procedure shown in the flowchart of FIG. In accordance with a command from the CPU, the color ink data and the fluorescent color ink data are received in a file format or the like (501, 502). First, emission intensity V ′ including CMYK absorption and emission intensity Vw ′ not including CMYK absorption are calculated from spectral reflectance data corresponding to the amount of color material used for each color ink CMYK used for printing (503). After setting the number of processed pixels to 0 (504), the ink amount of each color is calculated (505). The spectral reflectance data is created as look-up table data by measuring in advance a spectral reflectance corresponding to the amount used at each wavelength of 10 nm by a measuring instrument. Spectral reflectance lookup table data is prepared in advance in the ROM of the storage unit 112 for the spectral reflectance of each wavelength for four colors of CMYK. Based on this table, each of the four color inks CMYK printed on the recording medium. Spectral reflectance is obtained by interpolation of table values. Thereafter, the spectral reflectance of the pixel data of each color CMYK image to be printed is obtained by multiplying the spectral reflectance of each color ink CMYK for each wavelength.

  Further, a correction coefficient for the fluorescence emission intensity is obtained. In this embodiment, the correction coefficient is a ratio of the fluorescence ink emission intensity after being absorbed according to the spectral distribution of the reflectance of each color CMYK to be printed and the fluorescence ink emission intensity when not being absorbed by each color CMYK. Use to calculate. The emission intensity of the fluorescent ink is measured in advance by measuring the emission intensity at each wavelength of 10 nm in the visible region (from 380 nm to 780 nm) of a printed material in which the first fluorescent ink is applied to the recording medium at a usage amount of 100%. The measurement result is stored in advance in a ROM constituting the storage unit 112 as a lookup table.

  Hereinafter, a method of calculating the fluorescent ink amount of the pixel using the fluorescent ink will be described.

ここで、Ｒ_cmykはＣＭＹＫ４色のインクが重なる部分の分光反射率、Ｌ_ｆ１は第１の蛍光インクＦ１（図４参照）の分光分布特性を表す。
次に各色インクＣＭＹＫに吸収されなかった時、すなわち記録媒体単体での吸収分を加味した蛍光インクの発光強度Ｖｗを次式により求める。

また、各色インクＣＭＹＫのインク量がすべて０の場合は記録媒体上に各色インクＣＭＹＫが印字されていない状態であるため、ＶはＶｗの値に等しくなる。 First, the light emission intensity V of the fluorescent ink F after being absorbed according to the spectral reflectance of each color ink CMYK to be printed is obtained by the following formula 1.

Here, R _cmyk represents the spectral reflectance of the portion where the CMYK four color inks overlap, and L _f1 represents the spectral distribution characteristic of the first fluorescent ink F1 (see FIG. 4).
Next, when the respective color inks CMYK are not absorbed, that is, the emission intensity Vw of the fluorescent ink taking into account the absorption amount of the recording medium alone is obtained by the following equation.

Further, when the ink amounts of the respective color inks CMYK are all 0, since the respective color inks CMYK are not printed on the recording medium, V is equal to the value of Vw.

上述の操作により求めたＶ’およびＶｗ’から、補正後の蛍光画像の第１の蛍光インクの画像データＤｆ１を次式で求める（５０６）。

ここで、Ｄｆは端末より供給された蛍光画像データ、そしてｋは定数を表す。 Further, in order to reduce the amount of memory and the calculation load, for example, as shown below, the emission intensity of the fluorescent ink is determined every 10 nm, and V ′ and R ′ are replaced with the sum of the emission intensity for each 10 nm in the visible region. Vw ′ is calculated.

The image data Df1 of the first fluorescent ink of the corrected fluorescent image is obtained from the following equation from V ′ and Vw ′ obtained by the above operation (506).

Here, Df is fluorescence image data supplied from the terminal, and k is a constant.

  A gradation correction process is performed after the fluorescent image correction process is completed, and the corrected data is stored in the RAM of the storage unit 112 again. Similar to the CMYK data of each color stored in the RAM, the first fluorescent color ink image data Df1 of the corrected fluorescent image stored in the RAM is read. For each color CMYK data DcDmDyDk, the ink amount data IcImIyIk for each color is created using the conversion curve shown in FIG. In the conversion curve of FIG. 6, one conversion curve is assigned to each of the colors CMYK, thereby converting Dc to Ic, Dm to Im, Dy to Iy, and Dk to Ik.

  Next, with respect to the image data Df1 of the first fluorescent color ink, the ink amount data If1 of the first fluorescent ink after correction using the conversion curve shown in FIG. 6 and the second fluorescent ink after correction are corrected. Image data If2 is generated (507). In the conversion curve of FIG. 7, two conversion curves of Type 1 for If1 and Type 2 for If2 are assigned to the first fluorescent color F1, and Type2 for If2 are assigned to the second fluorescent color F2, respectively. Has been converted. This conversion curve has a characteristic that if the value of the input Df1 is equal to or less than k * F, If2 is 0 and only If1 is a positive value. For this reason, when there are no CMYK pixels in the same position, that is, where the CMYK pixels and the fluorescent ink pixels do not overlap on the medium, only the first fluorescent ink is used and the second fluorescent ink is used. Indicates that it will not be used. Further, if the value of the image data Df1 of the first fluorescent color ink is larger than k * F, If2 increases sequentially, but if1 decreases, the image data of the first fluorescent ink and the second fluorescent ink decreases. The total amount is kept below a certain value.

  The conversion curve has a specific table configuration. The corrected first fluorescent color ink F1 conversion table for ink amount data If1 corresponding to Type 1 and the corrected second table corresponding to Type 2. Two conversion tables for ink amount data If2 of the fluorescent color ink F2 are stored in the ROM in advance. As a result, it is possible to calculate both If1 and If2 by performing an interpolation calculation of the table value according to the value of Df1.

  The conversion processing is performed on all pixels (508, 509), and the ink amount data IcImIyIk of each color ink CMYK and the ink amount data If1If2 of the first and second fluorescent inks F1F2 are sequentially stored in the RAM (510). ).

  Hereinafter, printing on a recording medium will be described. FIG. 8 is a schematic diagram for explaining the operation of the inkjet head. First, the printer CPU 130 receives ink amount data of each color ink stored in the RAM of the storage unit 112, and controls the operations of the inkjet engine 133 and the head unit control unit 134. Ink jet head 700 ejects ink onto a recording medium in accordance with a command from printer CPU 130. The inkjet head 700 has a first printing unit 701, a second printing unit 702, and a third printing unit 703 as the first printing unit, and prints an image on a recording medium according to data from the RAM.

  FIG. 9 is a diagram for explaining the print areas of process ink and two types of fluorescent ink. As shown in the figure, the first printing unit 701 first prints inks CMYK of each color on a recording medium. Subsequently, the second printing unit 702 prints the first fluorescent color ink F1 around the area where the CMYK ink is not applied, and the third printing unit 703 further prints the second fluorescent color ink F2. Overprinting is performed centering on the area where CMYK ink has already been applied.

  As described above, it is possible to provide a reproducible image forming apparatus with high visibility of fluorescent color.

Hereinafter, a second embodiment will be described.
(Second Embodiment)
Since the configuration of the apparatus according to this embodiment is the same as that of the first embodiment, a description thereof will be omitted, and only different parts will be described.

  The image data of each color CMYK image and the image data of the fluorescence image stored in the RAM of the storage unit 112 are converted based on a gradation correction table prepared in advance in the ROM of the storage unit 112. This gradation correction table is prepared for each color C, M, Y, K, and fluorescent color F, and conversion is performed according to each table.

The fluorescence image correction process will be described below.
If1 and If2 are calculated using the two-dimensional table for ink amount data If1 of the first fluorescent ink and the two-dimensional table for ink amount data If2 of the second fluorescent ink, which are stored in advance in the ROM shown in FIG. To do. The If1 two-dimensional table is created in advance in consideration of the spectral reflectance of the first fluorescent ink and the spectral reflectance of the CMYK image data of each color, and the value of the first fluorescent ink F1 with respect to the fluorescent image data If is described. Yes. The If2 two-dimensional table is created in consideration of the spectral reflectance of the second fluorescent ink F2 and the spectral reflectance of each color CMYK image data, and the value of the second fluorescent ink F2 with respect to the fluorescent image data If is described. Yes.

  For each of the fluorescent color inks F1 and F2 prepared in advance, the spectral reflectance at the amount of CMYK color material used for printing is obtained, and the reduction rate of the emission intensity of the first fluorescent ink F1 is obtained. Then, a table using the second fluorescent ink F2 is created to compensate for the decrease. In addition, a table that reduces the usage amount of the first fluorescent ink F1 is created in order to prevent undulation of the printing medium due to an increase in the usage amount of ink (amount of adhesion to the recording medium) and ink bleeding on the printing medium. In these creations, as in the first embodiment, it may be obtained by calculation using a model formula, or may be obtained experimentally.

このＸとＩｆの値からＩｆ１用２次元テーブルを参照してＩｆ１データを、Ｉｆ２用２次元テーブルを参照してＩｆ２データを算出する。そして、算出されたＩｆ１、Ｉｆ２とインク量データＩｃ,Ｉｍ,Ｉｙ,Ｉｋ,ＩｆとをＲＡＭに格納する。 In the fluorescent image correction processing, first, Ic, Im, Iy, Ik, If ink amount data stored in the RAM is read, and the sum X of normal ink is calculated using the following equation.

From the values of X and If, the If1 two-dimensional table is referenced to calculate If1 data, and the If2 two-dimensional table is referenced to calculate If2 data. Then, the calculated If1, If2 and ink amount data Ic, Im, Iy, Ik, If are stored in the RAM.

  In this embodiment, by reducing the amount of calculation in the image forming apparatus, high-speed processing becomes possible, and the processing speed of the apparatus can be improved.

Next, a third embodiment will be described below.
(Third embodiment)
The overall configuration of the third embodiment is the same as that of the first embodiment.

The operation of the image processing apparatus is as follows.
In this embodiment, gradation processing is not performed in the image processing unit as in the second embodiment, and printing processing is performed after the gradation correction processing is completed.

  Of the ink amount data of Ic, Im, Iy, Ik, If1, and If2 stored in the RAM, Ic, Im, Iy, Ik, and If relating to the process ink CMYK are sent to the first printing unit 701. If1 related to the fluorescent ink F1 is transmitted to the second printing unit 702 and If2 related to the second fluorescent ink F2 is transmitted to the third printing unit 703 according to the instruction of the main CPU 110, respectively. Thereafter, data processing and transmission are executed for all pixels, and the process ends.

  When all the pixels are received, the first printing unit 701, the second printing unit, and the third printing unit turn the target pixel on or off according to the gradation pattern table stored in the storage unit 132. After performing gradation processing for determining whether to perform printing, the printing medium 704 is conveyed and printing is started. The image is printed sequentially with the first printing unit 701, the second printing unit 702, and the third printing unit 703, and the position of the recording medium 704 is made full use of the head unit control unit 134 and the conveyance control unit 135, respectively. By controlling the start of printing, printing is performed with the same pixel print position aligned.

  In this embodiment, gradation processing that matches the characteristics of the printing units 701 to 703 can be freely selected in each printing unit, and the print image quality can be improved without correcting the image processing unit.

  According to the image forming apparatus of at least one embodiment described above, the color material visible on the recording medium by visible light irradiation, the first fluorescent ink having the first emission intensity by ultraviolet irradiation, and the ultraviolet irradiation. Using the second fluorescent ink having a light emission intensity higher than the first light emission intensity, the first fluorescent ink is applied around a region where a color material that can be visually recognized on the recording medium is not applied. By applying the second fluorescent ink around the area where the color material that can be visually recognized on the recording medium is applied, the fluorescent color is visually recognized when a mixed image of a normal color image and a fluorescent image is printed on the printing medium. Reproducibility with high performance becomes possible.

  As mentioned above, although embodiment of this invention was described, this embodiment is shown as an example and is not intending limiting the range of invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

100 ... MFP (MFP)
110 ... Main CPU
103: Printer unit 130 ... Printer CPU
131 ... Inkjet engine 132 ... Storage unit 133 ... Inkjet engine 134 ... Head unit control unit 135 ... Process control unit 202 ... First image data generation unit 203 ... Second image data generation unit 204 ... Third image data generation unit 701 ... First printing unit 702 ... Second printing unit 703 ... Third printing unit

Claims (5)

A receiver for receiving color image data including a fluorescent color;
A first image data generation unit that generates image data for printing from a color material that can be visually recognized on a recording medium by irradiation with visible light from the color image data;
Created from the color image data by a first image data generation unit that records image data for printing using a first fluorescent ink having a first emission intensity by irradiation with ultraviolet rays at the same position on a recording medium. A second image data generation unit for generating the first image data according to the first image data;
A first image in which image data for printing using the second fluorescent ink having a light emission intensity higher than the first light emission intensity by the ultraviolet irradiation from the color image data is recorded at the same position on a recording medium. A third image data generation unit that generates the first image data generated by the data generation unit;
The first fluorescent ink is applied around the area where the color material visible on the recording medium is not applied, and the second fluorescence is applied around the area where the color material visible on the recording medium is applied. An image forming apparatus comprising: a printing unit that applies ink.   The second image data generation unit and the third image data generation unit correspond to the spectral reflectance obtained from the image data created by the first image data generation unit recorded at the same position on the recording medium. The image forming apparatus according to claim 1, wherein the image recording apparatus creates image data.   The second image data generation unit and the third image data generation unit calculate the sum of the values of the respective channels of the image data generated by the first image data generation unit recorded at the same position on the recording medium. The image forming apparatus according to claim 1, wherein image data is created in response. A receiver for receiving color image data including a fluorescent color;
A first image data generation unit that generates image data for printing from a color material that can be visually recognized on a recording medium by irradiation with visible light from the color image data;
Created from the color image data by a first image data generation unit that records image data for printing using a first fluorescent ink having a first emission intensity by irradiation with ultraviolet rays at the same position on a recording medium. A second image data generation unit for generating the first image data according to the first image data;
A first image in which image data for printing using the second fluorescent ink having a light emission intensity higher than the first light emission intensity by the ultraviolet irradiation from the color image data is recorded at the same position on a recording medium. A third image data generation unit that generates the first image data generated by the data generation unit;
An image forming unit that receives the first image data to the third image data and forms an image using a color material that can be visually recognized on a recording medium, the first fluorescent ink, and the second fluorescent ink;
Printing in which the first fluorescent ink is applied to an area where the color material visible on the recording medium is not applied, and the second fluorescent ink is applied to an area where the color material visible on the recording medium is applied And an image forming apparatus. Receive color image data including fluorescent color,
Generate image data for printing from the color image data using a color material that can be viewed on a recording medium by irradiation with visible light,
Created from the color image data by a first image data generation unit that records image data for printing using a first fluorescent ink having a first emission intensity by irradiation with ultraviolet rays at the same position on a recording medium. Generated according to the first image data,
A first image in which image data for printing using the second fluorescent ink having a light emission intensity higher than the first light emission intensity by the ultraviolet irradiation from the color image data is recorded at the same position on a recording medium. Generated according to the first image data created by the data generator,
Applying the first fluorescent ink to an area where the color material visible on the recording medium is not applied, and applying the second fluorescent ink to an area where the color material visible on the recording medium is applied. An image forming method.

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