JP3604806B2 - Recording device and recording method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a recording apparatus and a recording method for outputting information such as characters and images on a recording medium in an information processing system such as a copier, a facsimile, a printer, a word processor, and a personal computer.
[0002]
[Prior art]
A color image corresponding to input image data is formed using at least cyan (hereinafter, C), magenta (hereinafter, M), yellow (hereinafter, Y) color inks and black (hereinafter, Bk) inks. As one of the color image forming methods, under color removal from red (hereinafter, R), green (hereinafter, G), and blue (B) input signals or under color removal from C, M, and Y signals is performed. , Bk are generated.
[0003]
This image forming method has an advantage in an ink jet recording apparatus that the amount of ink to be discharged onto a recording material or the amount of ink consumed can be reduced.
[0004]
Further, compared to black (hereinafter, PCBk) generated on the recording material by the C, M, and Y inks, the black (hereinafter, TrueBk) on the recording material generated with the Bk ink has a higher reflection optical density. Is often high. In the case of PCBk, the color may be slightly different from black due to the characteristics of the C, M, and Y inks and the variation in the amount of ink to be printed on the recording material. By printing, a black image of a good color can be obtained. Further, when characters are formed by PCBk and dots on the recording material formed by C, M, and Y inks are shifted for some reason, color dots are seen at the edges of the character edges of the character image, and the print quality is high. Decreases. By forming a black character image with Bk ink, this can be eliminated.
[0005]
However, when the signal level of Bk is small (the higher the signal level, the darker the black of the input image will be described), dots of binary or several levels of density are formed on the recording medium to perform recording. When it is performed, there is a disadvantage that dots of Bk are sparsely formed on the recording medium, and the granular feeling is conspicuous.
[0006]
As a countermeasure, a method of forming a black portion of an image only with PCBk when the signal level of Bk is low and forming an image using TrueBk when the signal level of Bk is high has a small granularity. It is performed as a method of forming an image.
[0007]
In this method, as the signal level of Bk further increases, the ratio of TrueBk in the formation of a black image is gradually increased in order to avoid a sudden change in black color, or the Bk signal level is maximized. In this case, since this signal level is frequently used for a character image, it is generated only by TrueBk for the above-described reason.
[0008]
As a result, it is possible to form a recorded image with less graininess, high maximum reflection optical density, and good character image quality.
[0009]
[Problems to be solved by the invention]
The following problem was found in the ink jet recording apparatus using this image generation method.
[0010]
When an image with a large Bk signal level is recorded on a certain recording medium, a portion where the Bk signal level is maximum and a black image is formed only with TrueBk is used, and the Bk signal level is not maximum and both PCBk and TrueBk are used. The color of the recording material on which the image was formed was different at the portion where the black image was formed, and a step in color or density occurred at the boundary between the portions. As a result, a false contour due to the step, an image in which the color and density gradually change become unnatural, and the gradation quality deteriorates, thereby deteriorating the image quality.
[0011]
More detailed observations show that the portion where the Bk signal level is the maximum and a black image is formed only with TrueBk and the portion where the Bk signal level is not the maximum and a black image is formed using both PCBk and TrueBk and where the image is formed Have different surface states, and there are steps of color and density between regions.
[0012]
This is considered to be due to the fact that the amount of ink ejected to form a black image in the two regions is relatively large in the latter region. If the amount of ink to be ejected is small, most of the ink permeates into the recording material or into the coating layer provided on the surface of the recording material for fixing the ink. On the other hand, when the amount of ink applied is large, depending on the characteristics of the recording material, it takes time for all the ink to penetrate, and part of the ink that has landed on the recording material does not immediately Since changes in characteristics (for example, concentration and viscosity) occur due to evaporation of the solvent therein, a difference in the surface state between these two regions may occur.
[0013]
This phenomenon occurs when the color ink and the black ink have different permeation, fixation, and color development characteristics to the recording medium, and the color tone and density steps are large, and the image quality may be degraded. is there. For example, for color inks, use highly permeable inks to suppress ink bleeding, and for black inks, use low permeable inks to improve character quality. The concentration and viscosity increase due to the evaporation of the solvent, and the ink is fixed on the surface of the recording material and develops a color.) In some cases, ink is used.
[0014]
The object of the present invention is How to binarize an image, A recording device that can obtain extremely high image quality depending on the type of recording medium And recording method Is to provide.
[0015]
[Means for Solving the Problems]
The invention according to claim 1, wherein in a recording apparatus for forming an image on a recording medium using a recording agent of at least four colors including black, image type generating means for generating information indicating the type of the image; Recording medium type generating means for generating information indicating the type of image, a binarizing specifying means for specifying a binarizing method for an image, and using only a black recording agent when the black signal level of the image is maximum. Even if a black image is formed, even if the black signal level of the image is the maximum, the information indicating the type of the image is generated by the image type generating means as other than characters, and the information is recorded by the recording medium type generating means. When the information indicating the type of the medium is generated as a predetermined recording medium, and when the binarizing method specifies the error diffusion method by the binarizing specifying means, cyan, Zenta, characterized in that and control means for controlling to form the black image using the yellow recording agent.
[0016]
According to a second aspect of the present invention, in the first aspect, the recording medium type generating unit generates information indicating the type of the recording medium based on designation by the unit for designating the type of the recording medium. Features.
[0017]
According to a third aspect of the present invention, in the first aspect, the recording medium type generating unit is configured to perform the recording on the recording medium based on the identification by the unit that identifies the type of the recording medium based on a signal from a sensor provided in the recording apparatus. It is characterized by generating information indicating the type of medium.
[0018]
The invention according to a fourth aspect is characterized in that, in the first aspect, the image type generating means generates information indicating the type of the image based on designation by means for manually designating the type of the image.
[0019]
According to a fifth aspect of the present invention, in the first aspect, the image type generating means generates information indicating the type of the image based on identification by the means for identifying the type of the image based on the format of the image. Features.
[0020]
According to a sixth aspect of the present invention, in the first aspect, the control unit forms a black image only with a black recording material by changing a lookup table used for processing image data or a processing parameter. Or whether to form the black image using a cyan, magenta, or yellow recording agent in addition to a black recording agent.
[0021]
The invention according to claim 7 specifies an image type generating means for generating information indicating the type of image, a recording medium type generating means for generating information indicating the type of recording medium, and a binarizing method of the image. In a recording method in which an image is formed on a recording medium by using a recording material of at least four colors including black by a recording apparatus having a binarizing designating means, black recording is performed when the black signal level of the image is maximum. A black image is formed using only the agent, and even if the black signal level of the image is the maximum, the information indicating the type of the image is generated by the image type generating unit as information other than characters, and the type of the recording medium When the information indicating the type of the recording medium is a predetermined recording medium by the generating means, and the binarizing method specifies the error diffusion method by the binarizing specifying means, Cyan addition to recording agent, and controls so as to form the black image with magenta, a yellow recording agent.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the invention will be described in detail with reference to the drawings.
[0027]
FIG. 2 is a block diagram of a recording apparatus common to each embodiment of the present invention. In FIG. 2, 1 is an input gamma processing unit, 2 is a color correction processing unit, 3 is an under color removal / black generation processing unit, Denotes an output gamma processing unit, 5 denotes a binarization processing unit, and 6 denotes a recording unit. A control unit 7 controls each of the above-described components 1 to 6 (based on a user's instruction from an operation unit 8 to be described later as necessary). 8, a ROM storing the control procedures and the like shown in FIG. 8, a ROM storing the control procedures and the like in the ROM, a CPU for executing the control procedures in the ROM, and a RAM as a work area of the CPU. Reference numeral 8 denotes an operation unit having display means, input keys, and the like, and inputs operation information by a user to the control unit 7 as described later. The operation of each of the above components will be mainly described based on the first embodiment.
[0028]
<First embodiment>
In the recording apparatus according to the present embodiment, the levels of the C, M, and Y image signals are from 0 to 255 (the larger the signal, the deeper the color of the image). Of these three, the minimum signal level is the Bk signal. Level. Therefore, the maximum of the Bk signal level is 255. For the characters in the character image, the recording apparatus of the present embodiment uses the maximum signal level of Bk (that is, 255).
[0029]
In this embodiment, basically, when the Bk signal level is the maximum, the recording image is formed with TrueBk (that is, using only the Bk ink). When the user specifies the recording medium and the type of recording image in a predetermined combination, even if the Bk signal level is the maximum, both PCBk (black by combining C, M, and Y inks) and TrueBk are used. To form a recorded image.
[0030]
The printing apparatus used in this embodiment is an ink jet printing apparatus that performs binary printing using C, M, Y, and Bk inks. The operation of each component is as follows.
[0031]
(1) Input gamma processing unit 1
In this processing unit 1, the image data is received in the form of digital image data of a minimum of 0 to a maximum of 255 for each of R, G, and B colors. Upon receiving it, "input gamma processing" is performed using a predetermined conversion table. This processing includes, for example, whether to form an image that matches the color of the display of the information processing device that is the source of the R, G, and B image data, or to form an image that is linear in the signal level of the data. This is a process of converting and outputting input image data according to a predetermined conversion table in accordance with a user's designation from the operation unit 8. Further, here, the image data which was an RGB signal is converted into a CMY image signal.
[0032]
As an example, FIG. 3 shows an example of data of a conversion table adapted to the characteristics of the display.
[0033]
(2) Color correction processing unit 2
The processing in the processing unit 2 corrects the image data according to the color and density of the ink used for printing, the binarization method, and the coloring characteristics of the recording medium so that the formed image has the desired coloring. Processing.
[0034]
Here, the signals of C, M, and Y and the amount obtained by dividing the product thereof by the square of 256 (referred to as k for the sake of explanation) and the amount obtained by dividing the square of k by 256 (k2 for the sake of explanation) ) Is performed to convert the image data to obtain outputs C ′, M ′, and Y ′.
[0035]
C ′ = a11 · C + a12 · M + a13 · Y + a14 · k + a15 · k2
M '= a21 · C + a22 · M + a23 · Y + a24 · k + a25 · k2
Y ′ = a31 · C + a32 · M + a33 · Y + a34 · k + a35 · k2
As the constants a11 to a35, those corresponding to the recording medium, the binarization method, the resolution of image formation, and the like are stored (prepared) in, for example, the ROM of the control unit 7 in advance. Use as specified.
[0036]
(3) Under color removal / black generation processing unit 3
The undercolor removal processing and the black generation processing performed by the processing unit 3 will be described with reference to FIG. In FIG. 4A showing a conversion table for black generation processing, the horizontal axis represents the signal level of Bk of image data, and the vertical axis represents the output signal levels of C, M, and Y for forming a black image. And the output signal level of Bk.
[0037]
FIG. 4B for the undercolor removal processing shows a method of extracting the Bk signal level from C ′, M ′, and Y ′ from the color correction processing unit 2. The signal level of the smallest one of the input C ', M', and Y 'is output as the Bk signal level.
[0038]
Returning to FIG. In the figure, the horizontal axis is the Bk signal level after the undercolor removal, which is the input signal for this processing. The output includes a signal of PCBk and a signal of TrueBk, and the latter becomes Bk image data of the output of this processing as it is, and C, M, and Y subtract the Bk signal level from the respective input signals and reduce the Bk signal level to the Bk signal level. The sum of the corresponding PCBk signal values becomes the C, M, and Y image data in this processing.
[0039]
When the Bk signal level is low, a black image is formed by only PCBk (that is, only black by combining C, M, and Y dots). This is for reducing the graininess of the formed image and improving the image quality. In particular, since Bk ink dots are sparsely present in a human skin image, TrueBk is designed not to be used at a Bk signal level that is considered to correspond to human skin color.
[0040]
As the Bk level increases, TrueBk is added to reduce the proportion of PCBk. This is because the reflection optical density of a black image that can be generated on a printed image is lower than that of TrueBK on PCBk, and the amount of ink to be applied to a recording medium naturally increases when more PCBk is used. This is because adverse effects such as these tend to occur.
[0041]
When the Bk signal level is the maximum (that is, 255), a black image is formed only by TrueBk without using PCBk. This is to improve the image quality of the character image as described above. In this embodiment, black characters use the maximum signal level of Bk.
[0042]
In addition, this table is set so that the reflection optical density is linear with respect to the Bk signal level when a black image is formed on most recording media if the output gamma processing is appropriately set.
[0043]
(4) Output gamma processing unit 4
This processing is performed by the present recording apparatus so that each gradation of the C, M, Y, and Bk image data from the under color removal / black generation unit 3 matches the gradation of the image formed by the recording unit 7. Is a process of converting input image data using a conversion table prior to the formation of. FIG. 5 shows an example of the conversion table.
[0044]
(5) Binarization processing unit 5
The processing section 5 binarizes the image data from the output gamma processing section 4 by using a technique such as error diffusion or dithering.
[0045]
Then, the data subjected to these processes is sent to the recording unit 6, and an image is formed on the recording medium.
[0046]
In the present embodiment, the conversion table of the input gamma processing unit 2 is switched when the user specifies a combination of a recording medium in which the above-described problem occurs and a recording target other than a character image with the operation unit 8. , And linearly converts the data so that the signal level of the output data of the input gamma processing unit 2 becomes 250 at the maximum.
[0047]
Accordingly, when the under-color removal / black generation processing unit 3 performs the under-color removal processing and the black generation processing shown in FIG. 4, even if the input image level is at the maximum, the black is generated using both the PCBk and the TrueBk. An image is formed, and there is no step in color or density due to black gradation, thereby achieving the original purpose.
[0048]
FIG. 6 shows an example of data in the conversion table of the input gamma processing unit 2 in which the output data is set to a maximum of 250. This is a table for performing image formation according to the coloration of the display.
[0049]
FIG. 1 shows a processing flow of the present embodiment. That is, in S1, it is determined whether the combination of the recording medium and the recording target specified by the user from the operation unit is a predetermined combination, and if this is the predetermined combination as described above (Yes), the image data is On the other hand, the input gamma processing unit 1 executes input gamma processing in which the signal level of the output data is 250 at the maximum (S2), then, the color correction processing unit 2, the under color removal / black generation processing unit 3, and the output gamma processing unit 4 Each processing by the binarization processing unit 5 and the recording unit 6 is executed (S3 to S7).
[0050]
On the other hand, if the combination is not the predetermined combination in S1, the normal processing as described above is executed from the input gamma processing unit 1 to the recording unit 6 (S8 to S13).
[0051]
<Second embodiment>
In the first embodiment, depending on the recording medium and the recording target specified by the user, an image is formed only with TrueBk for the maximum signal of Bk with priority on character quality, or natural gradation and gradation are emphasized. Whether to form an image using both PCBk and TrueBk for the maximum signal of Bk was selected.
[0052]
In the second embodiment, the control unit 7 automatically detects the type of the recording medium by detecting the intensity of reflection on the recording medium based on a signal from an optical sensor provided in the recording apparatus, Further, the type of the image is automatically identified from the format of the input data and the input method of the data. Then, the control unit 7 controls the recording medium in which the image quality is deteriorated due to the difference in color, density, and surface condition of the recording medium between the image of TrueBK only and the image formed of PCBk and TrueBK. And if it is determined that the input data is originally a bitmap data and the like, it is highly likely that the input data is a photograph or graphics image, as in the first embodiment. The table is switched, and the output data of the input gamma processing is set to 250 at maximum.
[0053]
Accordingly, when the under color removal processing and the black generation processing are performed, a black image is formed using both PCBk and TrueBk even when the signal level of Bk is the maximum, and thereby the color and density in the black gradation are reduced. Can achieve the original purpose.
[0054]
By detecting the type of image data to be recorded (characters / line drawings, halftone images, etc.) and the type of recording medium, the burden of the user specifying them can be reduced. Furthermore, when different types of images are printed in the page of the image to be printed, the above control can be switched according to the types of the images, and as much as possible, the blackness can be reduced without deteriorating the character quality. Steps in color and density during gradation can be eliminated.
[0055]
<Third embodiment>
In the third embodiment, in addition to the designation of the recording medium by the user of the first embodiment from the operation unit and the designation of the recording target, the control is performed based on whether or not the designation of the binarization method is a predetermined combination. The unit 7 forms an image using only TrueBk for the maximum signal of Bk with priority on the character quality, or forms an image using both PCBk and TrueBk for the maximum signal of Bk with emphasis on natural gradation. Control.
[0056]
The recording apparatus of the present embodiment provides error diffusion, dithering of a matrix size of 8 × 8 pixels, and dithering of a matrix size of 16 × 16 pixels as a binarization method in the binarization processing unit 5. I have. Among them, binarization is performed by dithering of a size of 16 pixels × 16 pixels, and an image formed on a recording medium has a long dither pattern cycle, so that a subtle color change and a density change are inconspicuous. Therefore, the above-mentioned adverse effects due to the difference in color and density are unlikely to appear.
[0057]
On the other hand, when the Bk signal level of the image is linearly converted to a maximum of 250, the maximum density (reflective optical density) of black of the image formed on the recording medium decreases accordingly.
[0058]
Therefore, in this embodiment, in the recording medium in which the user's specification causes the above-described problem, the recording target specified by the user is other than a character image, and the binarization method is error diffusion or 8 pixels × In the case of a combination of dithering having a size of 8 pixels, the Bk signal level of the image in the input gamma processing unit 1 is linearly converted to a maximum of 250, as in the first and second embodiments.
[0059]
As a result, it is possible to form an image in which the reflection optical density of the character image is increased as much as possible while preventing the above-mentioned adverse effects due to the color and density steps.
[0060]
<Fourth embodiment>
In the fourth embodiment, by specifying the recording medium by the user using the operation unit, an image is formed only with TrueBk for the maximum signal of Bk with priority on character quality, or natural gradation is emphasized. The control to select whether to form an image using both PCBk and TrueBk for the maximum signal of Bk is selected. Then, similarly to the first embodiment, the conversion table of the input gamma processing unit 1 is switched to linearly convert the image data to a maximum of 250.
[0061]
The configuration of this embodiment is a simpler control than the previous embodiments, and has a function of designating the type of the recorded image by the user or a configuration in which the type of the image cannot be detected by the recording apparatus. In this case, the step of the color and the density in the black gradation described above can be eliminated, and the original object can be achieved.
[0062]
<Fifth embodiment>
In the first to fourth embodiments, the image data is linearly converted to a maximum of 250 in a predetermined case before the undercolor removal processing and the black generation processing by switching the conversion table of the input gamma processing unit 1. In the present embodiment, the parameters of the color correction processing in the color correction processing unit 2 are set so that the image data after the color correction is 250 at the maximum, and the user's specification from the operation unit is performed by the color correction processing unit 2. Is determined to be executed. If the user specifies to execute the color correction, the color correction is performed by the color correction processing unit 2 set to a maximum of 250. As a result, the data subjected to the undercolor removal processing and the black generation processing thereafter forms a black image using both PCBk and TrueBK for the maximum signal level of Bk. Then, depending on whether or not to perform the color correction processing, it is selected whether to create a black image corresponding to the maximum signal of Bk using only TrueBk or both TrueBk and PCBk. That is, in S14, when the user specifies from the operation unit that the color correction processing is performed, the image data is set so that the image data after the color correction after the input gamma processing by the input gamma processing unit 1 becomes 250 at the maximum. The color correction processing is performed by the color correction processing unit 2, and the processing by the under color removal / black generation processing unit 3, the output gamma processing unit 4, the binarization processing unit 5, and the recording unit 6 is executed (S17 to S20).
[0063]
If the user specifies no color correction processing in S14, after the input gamma processing, the processing by the under color removal / black generation processing and subsequent steps are executed as in S17 to S20 without performing the processing by the color correction processing unit 2 (S22). ~ S25).
[0064]
For images containing only character images and color graphs (hereinafter referred to as business graphics for convenience of explanation), subtle colors are not important, and gradation is generally considered to be almost insignificant. In the example, when a character image or business graphics is specified by the user, color correction processing is not performed, and only TrueBk constitutes black for the maximum signal level of Bk.
[0065]
On the other hand, if the image type of a natural image or general graphics (images that include gradation or display color reproduction is important) is specified, for example, the color that matches the display and print colors A correction process is performed, and at the same time, the image data is linearly converted to a maximum of 250. As a result, even when the signal level of Bk is the maximum, a black image is formed using both PCBk and TrueBk, and the above-described step of color and density in the gradation of black can be eliminated, thereby achieving the original purpose. can do.
[0066]
In the first to fifth embodiments, the object is achieved without changing the speed of the image processing as much as possible by changing the lookup table or the processing parameters used for processing the image data. However, in order to realize this function more easily, only when it is desired to form a black image corresponding to the maximum signal of Bk with TrueBk and PCBk, the image data is converted to a maximum value before the undercolor removal processing and the black generation processing. It suffices to insert a process for linear conversion into 250. This method has an advantage that the object can be achieved without complicating each processing such as the input gamma processing, but on the other hand, the time required for image processing is long.
[0067]
In the first to fifth embodiments, when a black image corresponding to the maximum signal of Bk is to be formed by TrueBk and PCBk, the image data is linearly converted to a maximum of 250 before undercolor removal processing and black generation processing. However, the present invention is not limited to this. In short, after the under color removal processing and the black generation processing, the PCBk is sufficiently used, and it is sufficient that the above-mentioned problem does not occur.
[0068]
<Sixth embodiment>
In the first to fourth embodiments, the image data is linearly converted to a maximum of 250 in a predetermined case before the undercolor removal processing and the black generation processing by switching the conversion table of the input gamma processing unit 1. In this embodiment, the table of the under color removal processing and the black generation processing in the under color removal / black generation processing unit 3 is composed of a table for forming an image only with TrueBk for the maximum signal of Bk, and a table for both PCBk and TrueBk. And two for forming an image by using the same. Then, the table used in the under color removal processing and the black generation processing is switched according to the user's designation of the recording medium from the operation unit. Thereby, the original purpose is achieved.
[0069]
FIG. 8 shows a control flow of the sixth embodiment. FIG. 9 shows an example of a conversion table for black generation processing in the under color removal / black generation processing unit used in this embodiment. FIG. 9A shows a table in the case where an image output is formed only by TrueBk when the signal level of Bk is the maximum, and FIG. 9B shows TrueBk when the signal level of Bk is the maximum. 4 shows a table in a case where an image output is formed using both PCBk. In the figure, the horizontal axis represents the Bk signal level, which is the input signal of this processing, similar to the above-mentioned FIG. 4B. The output includes signals of PCBk and TrueBk, and the latter becomes Bk image data of the output of this processing as it is, and C, M, and Y (PCBk) output the Bk signal level (described in the first embodiment) from the respective input signals. ), And the sum of the PCBk signal values corresponding to the Bk signal level becomes the C, M, and Y image data in this processing.
[0070]
As shown in FIG. 8, when the user specifies a recording medium of type A (material) in S26, the input gamma processing by the input gamma processing unit 1 and the color by the color correction processing unit 2 are performed in S26. After the correction (S27, S28), the under color removal / black generation processing unit 3 performs the under color removal / black generation processing using the table of FIG. 9A (S29), and then outputs the result by the output gamma processing unit 4. Gamma processing is performed (S30), binarization processing is performed by the binarization processing unit 5 (S31), and output processing is performed by the recording unit 6 (S32).
[0071]
In S26, when the user designates the type of recording medium of type B, after the processing of S33 and S34 similar to S27 and S28, in S35, the under color removal and black generation unit 3 of FIG. Under color removal / black generation processing is performed using the table, and the processing of S36 to S38 similar to S30 to S32 is performed.
[0072]
In the first to fifth embodiments, the under color removal processing and the black generation processing shown in FIG. 4A are performed, and when the signal level of Bk is the maximum (255), both the PCBk and the TrueBk are used. When it is desired to form a black image by using, the under color removal processing and the black generation processing are performed after linearly converting the image data into 250. If the control of the under color removal processing and the black generation processing is set so that the formed black image reflection optical density is linear with respect to the input signal (Bk signal level), the image data is linearly converted to 250. This results in a somewhat lower maximum reflection optical density of the formed image. In the configuration of the present embodiment, even when a black image is formed using PCBk and TrueBk, an image having a maximum reflection optical density similar to or higher than the case of forming a black image using only TrueBk can be formed. it can.
[0073]
In the first to sixth embodiments, the example in which the image signal of the character portion of the black character image uses the Bk maximum signal level has been described. However, the present invention is not limited to the configuration. When the image signal of a character is not at the maximum signal level of Bk, for example, in a printing apparatus that forms an image at half the resolution of another type of image, the image signal corresponding to a black character has a maximum signal level of Bk. It is conceivable that the signal level becomes half. However, considering that the quality of a character image is generally better when the density of the character portion is higher, it can be considered that characters can be printed with better character quality if the characters are formed at the maximum signal level of Bk.
[0074]
As described above, according to the above-described embodiment, the type of the recording medium is identified, and a difference occurs in color and density between the black image formed by TrueBk and the black image formed by both TrueBk and PCBk. When an image is formed on a recording medium, a black image of an image signal used to form a black character image is formed by using black obtained by combining cyan, magenta, and yellow in addition to black ink. In the region where the density of black is large, the boundary between the region on the recording medium formed only with TrueBk and the region on the recording medium formed with both TrueBk and PCBk can be eliminated, and the color generated there can be eliminated. And the image quality can be prevented from deteriorating due to the density difference.
[0075]
In the above-described embodiment, each processing unit in FIG. 2 is configured by hardware, but similar processing may be realized by software of a computer. That is, the processes of S1 to S6 and S8 to S12 in FIG. 1 may be performed on the host computer side that supplies image data to the recording unit 6.
[0076]
The operation unit 8 is a mouse and a keyboard as input devices of the host computer, and can manually input a type of a recording medium, a type of a target image, a binarization method, and the like.
[0077]
Further, the type of the image can be designated by the profile of the target image. In this case, when the target image is transferred to the recording apparatus or software for image formation on the host computer, data indicating the type of the image is generated.
[0078]
In the above-described example, ink jet recording is described as an example, but the concept of the present invention, such as a thermal transfer method, can be applied to other recording apparatuses.
[0079]
【The invention's effect】
As is clear from the above description, according to the present invention, it is possible to provide a recording apparatus and a recording method that can obtain an extremely high image quality according to a type of a recording medium and a method for binarizing an image. it can.
[Brief description of the drawings]
FIG. 1 is a diagram showing a control flow of a first embodiment.
FIG. 2 is a diagram for describing an outline of image processing according to the first embodiment.
FIG. 3 is a diagram for explaining input gamma processing according to the first embodiment;
FIG. 4 is a diagram for explaining undercolor removal processing and black generation processing according to the first embodiment;
FIG. 5 is a diagram for explaining output gamma processing of the first embodiment.
FIG. 6 is a diagram illustrating an example of a table of input gamma processing for explaining control of the first embodiment.
FIG. 7 is a diagram illustrating a control flow according to a fifth embodiment.
FIG. 8 is a diagram illustrating a control flow according to a sixth embodiment.
FIG. 9 is a diagram illustrating a table of an under color removal process and a black generation process used in a sixth embodiment.
[Explanation of symbols]
1 Input gamma processing unit
2 color correction processing unit
3 Under color removal / black generation unit
4 Output gamma processing unit
5 Binary processing section
6 Recorder
7 control section
8 Operation unit

Claims (7)

In a recording apparatus for forming an image on a recording medium using a recording agent of at least four colors including black,
Image type generating means for generating information indicating an image type;
Recording medium type generating means for generating information indicating the type of the recording medium,
A binarization designating means for designating a binarization method of the image;
When the black signal level of the image is the maximum, a black image is formed using only the black recording agent, and even if the black signal level of the image is the maximum, the information indicating the type of the image is obtained by the image type generating means. The recording medium type generating means generates information indicating the type of the recording medium as a predetermined recording medium, and the binarizing designating means executes the binarizing method. A control unit for controlling to form the black image by using cyan, magenta, and yellow recording agents in addition to the black recording agent when the error diffusion method is designated. . 2. The recording apparatus according to claim 1, wherein the recording medium type generating unit generates information indicating the type of the recording medium based on designation by a unit for designating the type of recording medium. 2. The recording medium type generating unit according to claim 1, wherein the recording medium type generating unit generates information indicating the type of the recording medium based on identification by the unit that identifies the type of the recording medium based on a signal from a sensor provided in the recording apparatus. A recording device, comprising: 2. The recording apparatus according to claim 1, wherein the image type generating unit generates information indicating the type of the image based on designation by a unit that manually designates the type of the image. 2. The recording apparatus according to claim 1, wherein the image type generating unit generates information indicating the type of the image based on identification by the unit that identifies the type of the image based on the format of the image. 2. The image forming apparatus according to claim 1, wherein the control unit changes the look-up table used for processing the image data or the processing parameters to form the black image only with the black recording material or add the black image to the black recording material. A recording apparatus for selecting whether to form the black image using cyan, magenta, and yellow recording agents. Image type generating means for generating information indicating the type of image, recording medium type generating means for generating information indicating the type of recording medium, and binarizing designating means for specifying a binarizing method for the image. A recording apparatus for forming an image on a recording medium using a recording agent of at least four colors including black,
When the black signal level of the image is the maximum, a black image is formed using only the black recording agent, and even if the black signal level of the image is the maximum, the information indicating the type of the image is obtained by the image type generating means. The recording medium type generating means generates information indicating the type of the recording medium as a predetermined recording medium, and the binarizing designating means executes the binarizing method. A printing method, wherein when the error diffusion method is designated, control is performed such that the black image is formed using cyan, magenta, and yellow printing materials in addition to the black printing material.

Images