JP2002125121A - Image processing method and image processing unit, and image forming device provided with them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing method adopted by even a simplified image processing unit that can quicken region isolation processing and enhance the region isolation accuracy. SOLUTION: In the preliminary scanning, an original discrimination section 11 uses received line image data to calculate the feature quantity of an original, discriminates the kind of original on the basis of the feature quantity and provides an output of an original discrimination signal. A parameter setting section 12 selects a discrimination reference (parameter) used by the main scanning in response to an original discrimination signal and provides an output. In the main scanning after that, a region isolating section 13 discriminates a region by using block image data consisting of X pixels in the main scanning direction and Y pixels in the subscanning direction on the basis of the parameter outputted from the parameter setting section 12. The region isolating section 13 gives the result of region discrimination, that is, a region isolation signal to a black generation/under color elimination section 7, a spatial filter section 8 and a medium tone generating section 9, in which optimum post-processing is applied to the image data by each pixel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing method and an image processing apparatus for performing a region separation process on input image data obtained by scanning an original document a plurality of times, such as a digital copying machine, and to provide the same. The present invention relates to an image forming apparatus.

[0002]

2. Description of the Related Art At present, in an image processing apparatus such as a digital copying machine, when an original in which characters and pictures are mixed is processed and reproduced, the original is converted into a character area, a halftone area and a photograph by a so-called area separation process. The image quality is improved by separating the image into regions such as regions and performing post-processing suitable for each region.

Further, by changing the criteria for the area separation processing according to the type of the original, the area separation accuracy and the image quality are improved. Such a technique is disclosed in, for example, an image processing method described in Japanese Patent Application Laid-Open No. 9-261460. In this image processing method, in the first (pre-scan) area separation, the type of the original is determined by increasing the area detection determination criterion, and the post-processing is switched according to the determination result, or the second or subsequent (pre-scan) area is used. By switching the criterion for the area separation (scan), the area separation accuracy and the image quality can be improved.

[0004]

Generally, in digital copiers and the like, the prescan operation tends to be faster than the main scan operation in order to shorten the copy time. In particular, when the original is scanned by the line sensor, the scanning time can be reduced by increasing the speed at which the line sensor moves in the sub-scanning direction. At this time, as for the image data in the sub-scanning direction at the time of the pre-scan, only the thinned data can be obtained. For example,
By increasing the pre-scan speed to twice the main scan speed,
Image data in the sub-scanning direction is reduced by half. That is,
The pre-scan image data has the same information amount in the main scanning direction as compared with the main scan image data,
Information is lost in the sub-scanning direction.

In the case of performing area separation using such prescanned image data, it can be said that image data in the sub-scanning direction lacks reliability and does not have sufficient information to determine an area. JP-A-9-261460 described above.
In the image processing method described in Japanese Patent Application Laid-Open Publication No. H10-270, the area determination is performed using the image data in block units in the area separation at the time of prescan, so that if the prescan speed is increased, the image data is insufficient. Accurate area determination becomes difficult, and the probability of occurrence of erroneous determination increases.

[0006] As described above, if the image data for the pre-scan and the image data for the main scan are to be used in block units constituted in the main scanning and sub-scanning directions, the operation time equivalent to the pre-scan and the main scan is equivalent. Therefore, the copy time is greatly increased, and if the data to be scanned is thinned out in order to shorten the operation time, the image data is insufficient, so that an erroneous determination occurs. Therefore, in order to increase the operation speed of the pre-scan and improve the accuracy of the area separation, the area is separated using the line-by-line image data constituted only in the main scanning direction at the time of the pre-scan, and the block is executed at the time of the main scan. It is desirable to perform area separation using unit image data.

As a technique for performing area separation using line image data in the main scanning direction at the time of prescan, Japanese Patent Laid-Open No.
An image processing device described in JP-A-112796 is disclosed. In this image processing apparatus, first, a line feature amount is calculated using line image data at the time of pre-scanning, and a long-period region determination is performed from the feature amount. At the time of the main scan, the feature amount of the block is calculated using the block image data, local region determination is performed from the feature amount, the line feature amount and the long-period region determination result, and the block feature amount and the local feature amount are determined. By performing area separation in accordance with the area determination results, the operation speed of the prescan is increased, and the area separation accuracy is improved. However, in this image processing apparatus, since the feature amount of the line and the long-period region determination result obtained in the pre-scan are used after the main scan, a page memory for storing these is necessary.

An object of the present invention is to provide an image processing method capable of speeding up the area separation processing and improving the area separation accuracy even when the apparatus is simplified.

[0009]

According to the present invention, there is provided an image processing method for performing a plurality of region separation processes on input image data obtained by scanning a document a plurality of times. This is an image processing method characterized by switching the range of input image data used for the area separation processing with the area separation processing, and transferring the processing result of the first area separation processing to the second area separation processing.

According to the present invention, the range of the input image data used for the area separation processing is switched between the first area separation processing and the second area separation processing. Even in this case, it is possible to perform a region separation process corresponding to each. In addition, since the processing result of the first area separation processing is transferred to the second area separation processing, by setting an appropriate method as the first area separation processing, the necessity of a page memory for holding the processing result is reduced. As a result, the apparatus can be simplified and the area separation accuracy can be improved.

In the present invention, the first region separation processing is performed based on line image data obtained in the main scanning direction.

Further, in the present invention, the second region separation processing is performed based on image data of a predetermined block unit obtained in the main scanning and sub-scanning directions.

According to the present invention, the first area separation processing is performed based on line image data obtained in the main scanning direction, and the second area separation processing is obtained in the main scanning and sub scanning directions. Since the processing is performed based on the block image data, the amount of data used is reduced to speed up the area separation processing,
It is possible to perform highly accurate region separation processing.

In the first region separation processing according to the present invention, the rise and fall of the pixel density change are detected from the line image data, and the region separation is determined for each line based on the detected rise and fall. It is characterized in that original type discrimination for the second region separation processing is performed.

According to the present invention, in the first region separation processing, the rise and fall of the pixel density change are detected from the line image data, and the region separation is determined for each line. Since the discrimination is performed, the area can be determined only by the line image data in the main scanning direction, and the type of the document can be determined using the determination result. Further, since the line image data in the main scanning direction is used, the scanning speed of a scanner, which is an image input device for scanning a document, can be increased.

In the present invention, the first region separation processing is to set a criterion used in the second region separation processing, and the second region separation processing is performed by using the criterion. Is performed.

According to the present invention, in the second segmentation process, segmentation is performed using the criterion set in the first segmentation process. Is set, and the accuracy of the region separation processing can be improved.

According to the present invention, there is provided an image processing apparatus wherein an input image data obtained by scanning a document a plurality of times is subjected to a plurality of segmentation processes using the above-described image processing method. .

According to the present invention, in the first region separation processing, processing is performed based on line image data obtained in the main scanning direction, and in the second region separation processing, processing is performed in the main scanning direction and the sub-scanning direction. An image processing apparatus that performs processing using a determination criterion, which is the first processing result, based on the obtained block image data, so that the amount of data used is reduced, the processing speed is increased, and high-precision region separation processing is performed. Can be provided. Further, since a page memory for storing the result of the first region separation processing is not required, the apparatus configuration is simplified and a low-cost image processing apparatus is provided.

According to the present invention, there is provided an image processing apparatus, image input means for scanning a document a plurality of times to read input image data, and a plurality of color images based on output image data output from the image processing apparatus. An image forming apparatus includes an image output unit that forms an image on a recording material using a visible color material.

According to the present invention, it is possible to provide an image forming apparatus which outputs a high quality image because the process speed is high because the amount of data to be used is small, and the accuracy of the area separation processing is improved.

Further, the present invention is characterized in that the scanning speed at which the image input means scans the original for the first time is set faster than the speed at which the image is scanned for the second time.

According to the present invention, for example, the first document scanning is performed by image input means (image input device) including a scanner (pre-scan), and the first area separation is performed on the read input image data. Processing is performed. Next, a second document scanning is performed (main scan), and a second region separation process is performed based on a result of the first region separation process. At this time, the scanning speed for scanning the original for the first time is set faster than the scanning speed for the second time (for example,
The first scanning speed is 2 times, 4 times, etc. of the second scanning). With such a setting, the time for performing the image processing can be shortened.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of an image forming apparatus 1 including an image processing apparatus 20 using an image processing method according to an embodiment of the present invention.

The image forming apparatus 1 includes an image input device 2 such as a scanner, an A / D (analog / digital) converter 3,
A shading correction unit 4, an input processing unit 5, a color correction unit 6,
An image processing apparatus 20 including a black generation / under color removal unit 7, a spatial filter unit 8, a halftone generation unit 9, a document discrimination unit 11, a parameter setting unit 12, and an area separation unit 13, and an electrophotographic system or an inkjet system. And an image output device 10 such as a printer.

First, the image input device 2 is composed of a scanner, and converts the light reflected from the original into a CCD (Charge Coupled Device).
The signal is converted into an electrical signal that is separated into R (red), G (green), and B (blue) by a line sensor. The color image signal (RGB analog signal) input by the CCD line sensor is
The signal is converted into a digital signal by the A / D converter 3, and the shading correction unit 4 removes various types of distortion generated in the illumination system, the imaging system, and the imaging system of the image input device.

Thereafter, the reflectance signal is converted into a density signal suitable for image processing in the input processing section 5, and the RGB signals are converted into CMY (C: cyan, M: magenta, Y: yellow).
A signal is generated. Next, the color correction section 6 performs processing for improving color reproducibility, and the black generation / under color removal section 7 performs CMYK processing.
(K: black) is converted into a four-color signal.

The spatial filter section 8 performs edge enhancement processing and smoothing processing on the CMYK signal, and the halftone generation section 9 performs gradation reproduction processing for outputting an image. Then, an output image is formed on a recording material such as paper by using an image output device 10 such as a printer using a plurality of visible color materials.

At this time, in order to enhance the reproducibility of each area of the original composed of areas such as characters, photographs and halftone dots, the area separating unit 13 determines to which area each pixel constituting the original belongs. Is determined to separate the two. The segmentation signal indicating the discrimination result is input to the black generation / under color removal unit 7, the spatial filter unit 8, and the halftone generation unit 9, and each unit performs post-processing suitable for each region.

For example, the black generation / under color removal unit 7 switches the black amount in accordance with the region separation signal to increase the black amount in the black character region while maintaining the gradation of the photograph region and the halftone dot region. Becomes possible. In the spatial filter section 8, the reproducibility of characters is improved by performing edge enhancement processing on the character area, and the occurrence of moire is prevented by performing smoothing processing on the halftone dot area. Further, in the halftone generation unit 9, the output image quality is improved by switching the matrix size of the dither processing according to each area.

In the image processing method according to the present invention, the area separating unit 1
The following processing is performed in order to improve the area separation accuracy in No. 3. First, in the first region separation processing, line image data obtained in the main scanning direction is extracted from input image data read by pre-scanning, and the document discriminating unit 11 determines whether a document is based on this line image data. It is determined which region is constituted, and a document discrimination signal as a processing result is output. According to that signal,
The criterion (parameter) used in the area separating unit 13 is set in the parameter setting unit 12. In the second region separation processing, predetermined block-unit image data (hereinafter, referred to as block image data) obtained in the main scanning direction and the sub-scanning direction is extracted from the input image data read by the main scan. Then, for the block image data, the region separating unit 13 determines the region to which each pixel belongs using the parameters passed from the parameter setting unit 12, and outputs a region separation signal.

As described above, according to the present invention, the range of the input image data used for the area separation processing is such that the line image data is used in the first area separation processing and the block image data is used in the second area separation processing. Is switched. Further, a criterion (parameter) is set based on a document discrimination signal which is a processing result of the first area separation processing, and the second area separation processing is performed using this criterion.

In the above description, the main scanning direction is a direction orthogonal to the scanning direction of a scanner as an image input device, and the sub-scanning direction means the same direction as the scanning direction of the scanner.

FIG. 2 is a block diagram showing the configuration of the document discrimination section 11. The document discriminating unit 11 includes a feature amount calculating unit 11
a, an area determining unit 11b, a counting unit 11c, and a document type determining unit 11d, and performs processing on line image data obtained in the prescan. Feature amount calculation unit 11a
Calculates two types of feature amounts for each Z pixel in the main scanning direction (or for each line) when line image data in the main scanning direction is sequentially input. The area determination unit 11b determines
It is determined whether the Z pixel portion belongs to a character, a halftone dot, a photograph, or any other area based on the type of feature amount. The area determination result is input to the counting unit 11c, and the number of each determination result is counted for characters, halftone dots, photographs, and other areas. Based on the count number, the document type determination unit 11
In step d, the document type is determined, and the area of the document is determined.

The first feature value and the second feature value calculated by the feature value calculator 11a will be described.

FIG. 3 is a diagram showing an example of a change in density value of line image data in each area. First, the density difference between adjacent pixels is equal to or greater than a predetermined threshold value, and a change from low density to high density is “rising” (upward arrow in the figure). Conversely, a change from high density to low density is determined. This density change is detected as “falling” (downward arrow in the figure). Then, the number of rising and falling in the Z pixel portion is calculated as the first feature amount. As shown in the example of each area in FIG. 3, the line image data belonging to the halftone dot and the character area has a large number of changes because the density greatly changes in the image data, and the other areas such as a photograph and a base have a small number of changes. Therefore, the number of changes is small. Therefore, when the first feature amount is large to some extent, it can be determined to be a halftone dot region or a character region.

FIGS. 4 and 5 are diagrams showing a second feature value calculating method. Similarly to the first feature amount, in the line image data, the number of pixels in the high-density portion from the rising edge to the falling edge is obtained as a continuous rising-falling number, and the difference in the number of pixels in the adjacent high-density portion is sequentially obtained. Go. The average value of the difference between the consecutive numbers is defined as an average value A. In the halftone dot area shown in FIG. 4, the rising-falling continuous number is 2, 3, 2, 3,
2, and the difference is calculated as 1, 1, 1, 1. Therefore, the average value A of the difference is (1 + 1 + 1 + 1) /
4 = 1 is calculated. On the other hand, as for the number of continuous falling-rising, the number of pixels in the low density portion is obtained, and the average value B is obtained in the same manner as the average value A. In FIG. 4, the falling-rising continuation number is detected as 3,2,3,2, and the difference is calculated as 1,1,1. Therefore, the average value B of the difference is (1 + 1 +
1) / 3 = 1 is calculated. As described above, the sum of the average value A and the average value B in the Z pixel portion is calculated as the second feature amount. Since the halftone dot region has periodicity, the average value A and the average value B are small since the difference in the number of continuations is small. In the character area shown in FIG. 5, the rising-falling continuous number is detected as 3, 2, 3, and 4, and the difference is 1,
It is calculated as 1,1. Therefore, the average difference A is (1
+ 1 + 1) / 3 = 1. On the other hand, the falling-rising consecutive number is detected as 5,2,4, and the difference is 3,2.
Is calculated. Therefore, the average value B of the difference is (3 + 2)
/2=2.5. The character area tends to have a large difference in the number of continuations. Therefore, when the second feature amount is relatively large, it can be determined that the character area is a character area.

The area determination unit 11b performs area separation determination on the line image data for each Z pixel using the first and second feature amounts calculated by the feature amount calculation unit 11a. First, if the first feature value is equal to or more than a predetermined threshold value, it is determined that the image is a halftone dot or a character area. . If the first feature value is smaller than a predetermined threshold value, it is determined that the area is another area.

The counting unit 11c counts the area separation determination result determined for each Z pixel for each of the character, halftone dot, and other areas, and calculates the character area count, halftone area count, and other area count for the document. Species determination unit 11
hand over to d.

When the ratio of the character area count number to the total count number is equal to or greater than a predetermined threshold value,
If the ratio of the halftone dot area count is smaller than a predetermined threshold, the type of the document is determined as a character document. In the opposite case, the document is determined as a halftone original. Further, when both the ratio of the character count number and the ratio of the halftone dot count are smaller than the predetermined threshold value, it is determined that the document is a photo original.
In other cases, the document is determined to be a mixed document in which regions are mixed in the document.

The parameter setting section 12 includes a document discriminating section 11
A parameter (for example, a threshold value) suitable for the type of the document is selected from a plurality of stored area separation parameters in accordance with the document determination signal indicating the document type determined by Hand over. The parameter suitable for the type of the original is, for example, a parameter set to sufficiently detect characters when the original is a text original, and similarly, when the original is a halftone original, the halftone dot is sufficiently detected. It is a set parameter. In the case of a photographic original, this is a parameter that does not perform the character detection process, and in the case of a mixed original, it is a parameter that avoids erroneous determination of area separation as much as possible.

As described above, in the pre-scan for setting the parameters used in the main scan, the range of the image data used for the area separation processing is the line image data in the main scanning direction. The scanning speed of the input device 2) can be increased.

FIG. 6 is a block diagram showing the structure of the area separating section 13. As shown in FIG. The area separating unit 13 includes a line memory 13
a, a character edge detection unit 13b, a halftone dot detection unit 13c, and an area determination unit 13d. In the second region separation processing, in the main scan, first, the input image data is stored in the line memory 13a so that the main scan direction X
An X × Y pixel block composed of pixels and Y pixels in the sub-scanning direction is formed. The range of the image data to be used is switched from the line image data of the first region separation processing to the block image data, and this is changed to the character edge detection unit 13b and the halftone dot detection unit 13c
To enter.

The character edge detecting section 13b detects an edge pixel (a pixel whose density difference from an adjacent pixel is larger than a predetermined threshold value) in a pixel block, and when the positional relationship of the edge pixel satisfies a certain condition, It is determined that the pixel block is a character block. For example, in the case of a 5 × 5 pixel block, when the positional relationship of the edge pixels is any of the six relationships shown in FIG. 7, the pixel block is determined to be a character block. If it is determined that the block is a character block, the character signal is output ON, and if not, OFF is output.

The halftone dot detecting section 13c first divides the pixel block into a plurality of local areas, and detects an extreme point (a pixel having an extremely large density difference from peripheral pixels) in the local area. Find the continuous number of local areas where the poles are detected in the pixel block,
If the value is larger than a predetermined threshold value, it is determined that the pixel block is a halftone dot block. When it is determined that the block is a halftone block, a halftone signal is output ON, and otherwise, OFF is output.

The plurality of thresholds used by the character edge detecting unit 13b and the halftone dot detecting unit 13c are parameters passed from the parameter setting unit 12, respectively. Are set, and in the case of a halftone original, parameters that are easy to determine as halftone are set.
In the case of a photo original, parameters are set so that edges and halftone dots are hardly detected. In the case of a mixed original, parameters are set so that erroneous detection of edges and halftone dots can be prevented and appropriately detected. ing. As a result, erroneous determinations in each detection unit can be reduced, and the area separation accuracy can be improved. Further, since the result of the first region separation processing is passed to the region separation unit 13 as a parameter, a storage unit such as a page memory for holding the result of the first region separation processing is not required, and the apparatus is simplified. Can be

The area judging section 13d includes the character edge detecting section 1
3b and a pixel block 1 corresponding to the character signal and the halftone signal detected from the halftone detection unit 13c, respectively.
It is determined whether the target pixel or pixel block, which is one pixel, belongs to a character, a halftone dot, or any other area. For example, if the halftone signal is ON, it is determined to be a halftone area, and if the halftone signal is OFF and the text signal is ON, it is determined to be a text area. If both signals are OFF, it is determined that the area is the other area. The region discrimination result is output as a region separation signal, passed to a black generation / under color removal unit 7, a spatial filter unit 8, and a halftone generation unit 9, and subjected to optimal post-processing.

FIG. 8 shows an image processing method according to the present invention.
It is a figure showing the processing flow of the 2nd and 2nd region separation processing. First, pre-scanning is started in step S 1, and line pixel data (Z pixels) in the main scanning direction is input to the document discrimination unit 11. The document discrimination unit 11 calculates a feature amount using the line image data. In step S2, the document type is determined based on the characteristic amount, and a document determination signal is output. In step S3, the parameter setting unit 12
The parameters used in the main scan are selected and output according to the document discrimination signal. Thereafter, in step S4, the main scan is started, and the image data is input to the area separating unit 13. At this time, the area separating unit 13 determines the area using block image data composed of the main scanning direction (X pixels) and the sub-scanning direction (Y pixels). In S5, the area determination result is transferred to the black generation / under color removal unit 7, the spatial filter unit 8, and the halftone generation unit 9 as an area separation signal, and the optimal post-processing is performed for each pixel.

[0050]

As described above, according to the present invention, by switching the data range used for the region separation processing, even if the amount of information obtained by a plurality of scans is different, the region separation corresponding to each of them is performed. Since the processing can be performed and a page memory for holding the processing result of the first region separation processing is not required, the apparatus can be simplified and the region separation accuracy can be improved.

Further, according to the present invention, it is possible to determine an area only by line image data in the main scanning direction, and to achieve high-precision area separation even if the scanning speed of the image input device is increased and the amount of data used is reduced. Processing can be performed.

Further, according to the present invention, the accuracy of the area separation processing is improved by setting an optimum criterion for the second area separation processing according to the type of the document determined by the first area separation processing. be able to.

According to the present invention, it is possible to provide an image processing apparatus which performs a high-accuracy region separation process by reducing the amount of data used and increasing the processing speed. Further, since a page memory for storing the result of the first region separation processing is not required, the apparatus configuration is simplified and a low-cost image processing apparatus is provided.

According to the present invention, it is possible to provide an image forming apparatus that outputs a high-quality image because the process speed is high because the amount of data used is small, and the accuracy of the area separation processing is improved.

According to the present invention, for example, the first scanning speed of the image input means (image input device) including a scanner is set to be faster than the second scanning speed (for example, the first scanning speed). Scanning speed of the second 2
, 4 times, etc.), so that the time for performing the image processing can be shortened.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an image forming apparatus 1 including an image processing apparatus 20 using an image processing method according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a document discrimination unit 11.

FIG. 3 is a diagram illustrating an example of a change in density value of line image data in each area.

FIG. 4 is a diagram illustrating a second feature value calculation method using a halftone dot region as an example.

FIG. 5 is a diagram illustrating a second feature value calculation method using a character area as an example.

FIG. 6 is a block diagram illustrating a configuration of a region separating unit 13;

FIG. 7 is a diagram illustrating a method of determining whether a pixel block is a character block.

FIG. 8 shows the first and second processes in the image processing method of the present invention.
It is a figure showing the processing flow of the 2nd area separation processing.

[Explanation of symbols]

 Reference Signs List 1 image forming apparatus 2 image input apparatus (image input means) 3 A / D (analog / digital) conversion section 4 shading correction section 5 input processing section 6 color correction section 7 black generation / under color removal section 8 spatial filter section 9 intermediate Tone generation unit 10 Image output device (image output means) 11 Document discrimination unit 11a Feature amount calculation unit 11b Area judgment unit 11c Count unit 11d Document type judgment unit 12 Parameter setting unit 13 Area separation unit 13a Line memory 13b Character edge detection unit 13c Halftone dot detection unit 13d Area determination unit 20 Image processing device

Claims (8)

[Claims] 1. An image processing method for performing a plurality of region separation processes on input image data obtained by scanning a document a plurality of times, wherein a first region separation process and a second region separation process are performed. An image processing method, wherein a range of input image data used for processing is switched, and a processing result of a first region separation process is transferred to a second region separation process. 2. The image processing method according to claim 1, wherein the first region separation processing is performed based on line image data obtained in a main scanning direction. 3. The image according to claim 2, wherein the second region separation processing is performed based on image data in a predetermined block unit obtained in the main scanning and sub-scanning directions. Processing method. 4. The first region separation process detects a rise and a fall of a pixel density change from line image data, performs a region separation determination for each line based on the detected rise and fall, and uses the determination result to perform the 2nd region separation. 3. The image processing method according to claim 2, wherein a document type is determined for a second region separation process. 5. The first area separation processing is to set a criterion used in the second area separation processing.
5. The method according to claim 1, wherein the second segmentation process is a segmentation process using the criterion.
The image processing method according to any one of the above. 6. An image processing method according to claim 1, wherein a plurality of segmentation processes are performed on input image data obtained by scanning a document a plurality of times. Image processing device. 7. An image processing apparatus according to claim 6, an image input means for scanning a document a plurality of times to read input image data, and a plurality of color images based on output image data output from said image processing apparatus. An image forming apparatus, comprising: an image output unit that forms an image on a recording material using a visible color material. 8. The image forming apparatus according to claim 7, wherein a scanning speed at which the image input means scans the original for the first time is set faster than a speed at which the image is scanned for the second time.