JPH114354A - Image reading device - Google Patents

Abstract

(57) [Problem] To provide a low-cost image reading apparatus capable of distinguishing the type of a document in a short time by reading the document with different color separation characteristics for each line of the document. A halogen lamp for irradiating a document with light,
An illumination drive circuit that controls the drive by switching the spectral emission characteristics of the halogen lamp on a line-by-line basis of the original, a dichroic prism that separates the reflected light from the original illuminated by the halogen lamp, and a reflected light that is separated by the dichroic prism. CCDs 108r, 108g, 108b for receiving and photoelectrically converting and reading as image signals;
r, 108g, and 108b, the system control unit 106 that determines the type of the document based on the image signals read.
And

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus for detecting the type of an original, and more particularly, to an image reading apparatus used in a copying machine for detecting the type of an original and performing an optimum process. .

[0002]

2. Description of the Related Art For example, in an image reading apparatus for reading a document by color separation, the same color appears to the human eye depending on the type of the document (more precisely, the type of color material used in the document). Is also known to be read as a different color. Therefore, various devices have been proposed for detecting the type of the original, changing the image processing method according to the result, and obtaining a stable image regardless of the type of the original.

[0003] For example, there is an apparatus disclosed in Japanese Patent Publication No. 5-83142 entitled "Color Document Type Classification Apparatus". Such an apparatus uses a first measuring means having a sensitivity peak in a wavelength range of about 370 nm to 420 nm and a second measuring means having a sensitivity peak in other wavelength ranges to reflect reflected light of a color original. Is measured, the obtained two measured values are compared, and the color image is classified into a photographic image and a printed image based on the comparison result. That is, this apparatus is provided with a sensor different from the normal three primary color sensors for detecting the type of the original.

Further, there is an image forming apparatus disclosed in Japanese Patent Application Laid-Open No. Hei 2-168770 "Image forming apparatus". Such a device is
In order to measure the reflected light of the original, two types of sensors having sensitivity peaks at different wavelengths within the wavelength range of one primary color light are provided for each of the three primary colors. The type is determined. That is, the apparatus includes a sensor having two different sensitivity peaks for each of the three primary colors to detect the type of the document.

[0005] Also, there is one disclosed in Japanese Patent Application Laid-Open No. 9-46533 "Color Image Input Apparatus". In such an apparatus, the color separation means separates the reflected light from the document illuminated by the document illuminating means into colors, the image reading means photoelectrically converts the color-separated reflected light and reads it as an image signal, and the color material determining means The type of the color material of the document is determined based on the read image signal, and the color correction unit is used for the image signal read by the image reading unit based on the determination result of the color material determination unit. This is to perform optimal color correction processing according to the type of color material. In other words, this device outputs an image signal obtained by reading a document with color separation characteristics that are different from one another in the order of the frames.

[0006]

However, Japanese Patent Publication No. Hei 5-83142 and Japanese Patent Laid-Open Publication No. Hei.
In the device disclosed in Japanese Patent Application Laid-Open No. 9-1990, a new sensor is required in addition to the normal three primary color sensors. Therefore, the configuration of the device becomes complicated in consideration of the sensor and the circuit associated with the sensor. However, there is a problem that the cost is high.

Further, in the apparatus disclosed in Japanese Patent Application Laid-Open No. 9-46533, the color separation characteristics are made different in a plane-sequential manner, so that at least two preliminary reading operations are required to determine the type of the original. There is a problem of lack of immediacy. In other words, in the apparatus disclosed in Japanese Patent Application Laid-Open No. 9-46533, an original reading operation is performed prior to an actual copying operation in order to determine the type of color material used in the original. There is a problem that the time from the pressing of the copy start key to the end of discharge of the copy is prolonged by the increased amount.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a low cost that can determine the type of a document in a short time by reading the document with different color separation characteristics for each line of the document. It is an object of the present invention to provide an image reading device.

Another object of the present invention is to provide an image capable of outputting a high-quality image signal by eliminating unevenness in shading correction characteristics when an original is read with different color separation characteristics for each line of the original. It is an object to provide a reader.

[0010]

In order to achieve the above object, an original illuminating means comprising a plurality of illumination sources which can be driven independently and have different spectral emission characteristics, and a plurality of illumination sources. Illuminating drive control means for independently driving and controlling the spectral luminescence characteristics of the original illuminating means for each original line, and a color for separating the reflected light from the original illuminated by the original illuminating means. Separation means, image reading means for receiving the reflected light color-separated by the color separation means, photoelectrically converting the reflected light and reading it as an image signal, and determining the type of the document based on the image signal read by the image reading means Document type determining means.

In other words, the illumination drive control means drives each of the plurality of illumination sources independently, and controls the drive by switching the spectral emission characteristics of the original illumination means in units of original lines.
The color separation means separates the reflected light from the document illuminated by the document illuminating means into colors, and the image reading means receives the reflected light separated by the color separation means, photoelectrically converts the light, reads the image signal, and reads the image signal. The determining means determines the type of the document based on the image signal read by the image reading means.

According to a second aspect of the present invention, there is provided an image reading apparatus, comprising: a document illuminating means comprising a single illuminating source for irradiating a document with light; Illumination drive control means for switching and controlling the driving, color separation means for color-separating the reflected light from the document illuminated by the document illuminating means, and receiving the reflected light color-separated by the color separation means for photoelectric conversion An image reading unit that reads the image as an image signal; and a document type determining unit that determines the type of the document based on the image signal read by the image reading unit.

That is, the illumination drive control means controls the drive by switching the spectral emission characteristics of the original illuminating means for each original line, and the color separating means performs color separation on the reflected light from the original illuminated by the original illuminating means. The image reading means receives the reflected light color-separated by the color separation means, photoelectrically converts the light and reads it as an image signal, and the document type determination means determines the type of the document based on the image signal read by the image reading means. Is determined.

According to a third aspect of the present invention, there is provided an image reading apparatus, comprising: an original illuminating unit for irradiating an original with light; an optical path between the original illuminating unit and the original; An optical filter having a plurality of spectral transmission characteristics disposed between the optical paths of the light source and the optical filter; and driving the optical filter to change a spectral transmission characteristic of illumination light from the original illuminating unit or reflected light from the original. An optical filter driving means for varying the line of the document, a color separating means for color separating reflected light from the document illuminated by the document illuminating means, and a light receiving means for receiving the reflected light separated by the color separating means. Image reading means for photoelectrically converting and reading as an image signal; and document type determining means for determining the type of the document based on the image signal read by the image reading means. It was.

That is, optical filter means having a plurality of spectral transmission characteristics are arranged between the optical path between the original illuminating means and the original or between the optical path between the original illuminating means and the photoelectric conversion means.
The optical filter driving means drives the optical filter means to vary the spectral transmission characteristics of the illumination light from the original illuminating means or the reflected light from the original for each line of the original, and the color separation means illuminates the original illumination means. The reflected light from the read original is color-separated, the image reading unit receives the reflected light separated by the color separating unit, photoelectrically converts the received light, reads it as an image signal, and the original type determination unit reads it by the image reading unit. The type of the document is determined based on the received image signal.

According to a fourth aspect of the present invention, in the image reading apparatus according to any one of the first to third aspects, the image signal read by the image reading means differs in line units. A shading correction unit for performing shading correction, wherein the document type determining unit determines the type of the document based on the image signal subjected to shading correction by the shading correction unit.

According to a fifth aspect of the present invention, in the image reading apparatus of the first, second, or fourth aspect, the drive control means alternately operates for each line.
The spectral illuminating characteristic of the document illuminating means is switched between a first spectral luminous characteristic and a second spectral luminous characteristic.

Further, in the image reading apparatus according to the present invention, the drive control means alternately changes the spectral emission characteristics of the document brightening means for every one to N (N> 1) lines. The light emission characteristic and the second spectral emission characteristic are switched.

According to a seventh aspect of the present invention, in the image reading apparatus according to the third or fourth aspect, the optical filter driving means alternately switches the optical filter means for each line. The spectral transmission characteristic is switched between the first spectral transmission characteristic and the second spectral transmission characteristic.

According to an eighth aspect of the present invention, in the image reading apparatus of the third or fourth aspect, the optical filter driving means alternates every one to N (N> 1) lines. Then, the spectral transmission characteristic of the optical filter means is switched between a first spectral transmission characteristic and a second spectral transmission characteristic.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment in which an image reading apparatus according to the present invention is applied to a digital copying machine will be described as an example of [Embodiment 1], [Embodiment 2], [Embodiment 3], [Embodiment 3]. Embodiment 4], [Embodiment 5], and [Embodiment 6] will be described in detail in this order with reference to the drawings.

[Embodiment 1] FIG. 1 is a block diagram of a digital copying machine according to Embodiment 1 of the present invention, in which an original image is read and a read color gradation signal red (R), green (G) and A reading processing unit 101 that outputs blue (B), a sampling unit 102 that samples reading color gradation signals R, G, and B of a document image read by the reading processing unit 101, and a reading color gradation from the reading processing unit 101. An image processing unit 103 for inputting signals R, G, and B to perform various image processing, and an image processing unit 10
An image recording unit 104 for outputting the image data subjected to the image processing at 3 on a recording sheet;
1, sampling unit 102, image processing unit 1
03 and the image recording unit 104, and a synchronization control unit 105 for matching the timing of signal transmission and reception between each element in each unit, and controls the entire digital copying machine and determines the original type according to the first embodiment. It comprises a system control unit 106 as a means, and a console board 107 having a display unit and a key unit and operating the entire digital copying machine.

Next, detailed configurations of the reading processing unit 101, the image processing unit 103, the image recording unit 104, and the system control unit 106 will be described with reference to the drawings.

First, the reading processing unit 101 receives the reflected light corresponding to R, G, and B separated by a dichroic prism 206, which is color separation means, which will be described later, and photoelectrically converts the reflected light to read a CCD 108 as an image signal.
r, 108g and 108b and CCDs 108r and 10
8g and the image signal read at 108b (here,
A / D converters 109r, 109g and 109b for converting analog signals) into digital signals, and A / D converter 1
A shading correction circuit 110 as shading correction means for inputting image signals converted into digital signals at 09r, 109g and 109b and performing shading correction.

The image processing unit 103 includes a gamma correction circuit 111 for performing logarithmic conversion on the input read color gradation signals R, G, and B, and a color correction circuit as a color correction processing means for performing masking processing. 112 and the read color gradation signal R,
A scaling processing circuit 113 for performing scaling processing on G and B;
And a dither processing circuit 114 for performing dither processing based on the signal subjected to the scaling processing by the scaling processing circuit 113.

The image recording unit 104 includes a buffer memory 115 for storing the recording color gradation signals input from the image processing unit 103, a semiconductor laser 116,
And a laser driver 117 for driving the semiconductor laser 116.

The buffer memory 115 has buffer color memories 115c and 115m for recording color gradation signals cyan (C), magenta (M) and yellow (Y) corresponding to the recording density of each toner. 115
y. Further, similarly to the buffer memory 115, the semiconductor laser 116 has the recording color gradation signals C, M and Y.
At the same time, the semiconductor lasers 116c, 116m, 116y and 116b are used for the fourth black (BK).
k. Further, similarly to the semiconductor laser 116, the laser driver 117 also responds to the laser drivers 117c, 117m, and 1 for the recording color gradation signals C, M, Y, and BK.
17y and 117bk.

Further, the system control unit 106
A CPU 118 for controlling the entire digital copying machine;
ROM 119, RAM 120, and read processing unit 1
01, and an I / O port 12 for connecting to the sampling unit 102.
2 and I / O for connecting to the image processing unit 103
A port 123, an I / O port 124 for connecting to the image recording unit 104, an I / O port 125 for connecting to the synchronization control unit 105, and an I / O port for connecting to the console board 107 126
And In other words, the system control unit 1
06 is a microcomputer. Further, the system control unit 106 includes a console board 10 described later.
Predetermined control and operation are performed in response to the display control and key input of (7).

The operation of the above configuration will be described. First, the reading processing unit 101, the sampling unit 102, the image processing unit 103, the image recording unit 104, the system control unit 106, and the console board 107 will be described in this order.

In the reading processing unit 101, a CCD
Reference numerals 108r, 108g, and 108b read the original for each color and output R, G, and B output signals. CC
The output signals of D108r, 108g and 108b are A
The digital signals are converted into 10-bit digital signals by the / D converters 109r, 109g, and 109b, respectively, and input to the shading correction circuit 103. The shading correction circuit 103 is provided for controlling unevenness in illuminance of the reading optical system of the CCD 108,
A correction is made for the variation in the sensitivity of the light receiving element group inside each of the CCDs 108r, 108g and 108b and the dark potential, and the read color gradation signals R, G and B of 10 bits each are applied.
Is output.

The sampling unit 102 converts the read color tone signals R, G, and B input from the read processing unit 101 at predetermined timings set in advance, for example, on grid points when the original is divided by grids at regular intervals. Sampling with etc. The sampling performed by the sampling unit 102 is performed, for example, after performing a smoothing process or the like to remove noise and the like included in the read color tone signals R, G, and B in order to prevent erroneous determination of the type of color material, which will be described later. It is desirable to do.

Next, in the image processing unit 103,
The γ correction circuit 111 receives the read color gradation signals R, G
Logarithmic conversion of the read color density signals Dr, Dg of R, G, and B of 8 bits each in accordance with an instruction from the console board 107.
And Db.

Next, the color correction circuit 112 performs a masking process, and based on the read color gradation signals R, G and B, the read color density signals Dr, Dg and Db as input signals are
The signals are converted into signals Dc, Dm, Dy and Dbk corresponding to the recording colors of C, M, Y and BK (corresponding to the recording density of each toner). In the conversion performed by the color correction circuit 112, basic color correction for correcting the deviation of the recording characteristics from the ideal characteristics of the digital copying machine according to the first embodiment, and arbitrary color correction based on an instruction from the console board 107 As will be described in further detail later, a color correction process is performed according to the type of color material used for the document according to the first embodiment.

The 8-bit recording color density signals Dc, Dm, Dy and Dbk output from the color correction circuit 112 are:
It is applied to the scaling processing circuit 113. Magnification processing circuit 113
Performs a scaling process in the main scanning direction (a direction perpendicular to the moving direction of the first carriage 207 described later) on the signals of each color in response to an instruction from the console board 107, and
It outputs bit recording color density signals Dc ′, Dm ′, Dy ′ and Dbk ′. Note that the magnification in the sub-scanning direction (the moving direction of the first carriage 207) is changed by the first carriage 207.
This is performed by changing the moving speed of the camera.

The signal output from the scaling processing circuit 113 is applied to a dither processing circuit 114. The dither processing circuit 114 performs dither processing on the recording density signals Dc ′, Dm ′, Dy ′ and Dbk ′, and outputs 3-bit recording color gradation signals C, M, Y and BK. In the dither processing performed by the dither processing circuit 114, correction of the non-linear characteristics on the gradation of the recording system is also performed.

The semiconductor lasers 116c, 116m, 116y and 116bk are energized in accordance with the recording color gradation signals C, M, Y and BK output from the image processing unit 103. Note that the recording color gradation signal BK is directly supplied to the laser driver 117bk.
And Y are buffer memories 115y and 11y, respectively.
After being held at 5 m and 115 c, the buffer memory 11 is delayed by a preset time Ty, Tm and Tc.
5y, 115m, and 115c, and are provided to laser drivers 117y, 117m, and 117c.

Next, the basic configuration and operation of the digital copying machine will be described with reference to FIG. Manuscript 201
Is placed on the contact glass 202, and the first embodiment is used.
Halogen lamps 203a and 203 as document illuminating means
b. Halogen lamps 203a, 203
b irradiates the original 201 and generates reflected light, which is moved to the movable first mirror 204a, the second mirror 204b, and the third mirror 204b.
The light is reflected by the mirror 204c, passes through the imaging lens 205, and enters the dichroic prism 206, which is the color separation unit of the first embodiment.

In the dichroic prism 206,
The reflected light is split into three wavelengths of light, namely, red (R), green (G), and blue (B). The split light is transmitted to CCDs 108r and 108, which are solid-state imaging devices.
g and 108b. As described above, of the incident light, red light is emitted to the CCD 108r, green light is emitted to the CCD 108g, and blue light is emitted to the CCD 10r.
8b.

The halogen lamps 203a and 203b
The first mirror 204a is mounted on a first carriage 207, and the second mirror 204b and the third mirror 204c are mounted on a second carriage 208.
The second carriage 208 is の of the first carriage 207
By moving at the speed of
The first carriage 207 and the second carriage 208 are scanned from right to left when reading the original image.

The first carriage 207 is connected to a carriage drive wire 211 wound around a carriage drive pulley 210 fixed to the shaft of the carriage drive motor 209.
And a carriage drive wire 211 is wound around a moving pulley (not shown) on the second carriage 208. Thus, the first carriage 207 and the second carriage 20 are driven by the forward / reverse rotation of the carriage drive motor 209.
8 moves forward (original image reading scan) and moves backward (return), and the second carriage 208 moves at half the speed of the first carriage 207.

When the first carriage 207 is at the home position shown in FIG. 2, the first carriage 207 is a home position sensor 212 which is a reflection type photo sensor.
Is detected by FIG. 3 shows how the home position sensor 212 detects the first carriage 207.

In the figure, when the first carriage 207 is driven rightward by exposure scanning and deviates from the home position, the home position sensor 212 does not receive light (the first carriage 207 is not detected). On the other hand, when the first carriage 207 returns to the home position by return, the home position sensor 212 receives light (the first carriage 20).
7 detection), and when the state changes from non-light reception to light reception, the first
The carriage 207 is stopped.

Here, referring to FIG.
The outputs of r, 108g and 108b are subjected to analog / digital conversion and subjected to necessary processing in the image processing unit 103, so that black (BK), yellow (Y), magenta (M) and cyan ( C) Each signal is converted into a binary signal for recording.

Each of the binarized signals is input to laser drivers 117bk, 117y, 117m, and 117c, and each of the laser drivers outputs a corresponding one of the semiconductor lasers 116bk, 1b.
By energizing 16y, 116m and 116c, a laser beam modulated with a recording color signal (binary signal) is emitted.

The emitted laser beams are, as shown in FIG. 2, respectively, rotating polygon mirrors 213bk, 213y, and 213b.
m, and reflected by 213c, f-θ lens 214b
k, 214y, 214m, and 214c, the fourth
Mirrors 215bk, 215y, 215m, and 215
c, and is reflected by the fifth mirrors 216bk, 216y, 216m, and 26c, and passes through the polygon mirror tilt correction cylindrical lenses 217bk, 217y, 217m, and 217c, and the photosensitive drums 218bk, 218y, 218m,
And 218c.

Rotating polygon mirrors 213bk, 213y, 213
m and 213c are polygon mirror drive motors 219bk,
219y, 219m and 219c are fixed to the rotating shafts. Polyhedral mirror drive motors 219bk, 219y, 21
9m and 219c rotate at a constant speed, and rotate the rotary polygon mirrors 213bk, 213y, 213m and 213c at a constant speed.

Further, the rotary polygon mirrors 213bk, 213y,
Due to the rotation of the photoconductor drums 218bk, 218y, 218m, and 218c, the laser light is emitted in a direction perpendicular to the rotation direction (clockwise) of the photoconductor drums 218bk, 218y, 218m, and 218c. It is scanned in a direction along the axis.

Here, the laser scanning system of the cyan recording apparatus will be described in detail with reference to FIG. As mentioned above, 1
16c denotes a semiconductor laser. At one end of laser scanning (two-point mirror line) in the direction along the axis of the photosensitive drum 218c, a sensor 220c, which is a photoelectric conversion element, is provided so as to receive laser light, and the sensor 220c detects the laser light. Then, the start point of one-line scanning is detected at the time point when the state changes from detection to non-detection.

That is, the laser light detection signal (pulse) of the sensor 220c is processed as a line synchronization pulse for laser scanning. The configurations of the magenta recording device, the yellow recording device, and the black recording device are exactly the same as the configuration of the cyan recording device shown in FIG.

Returning to FIG. 2, the description will be continued. The surfaces of the photosensitive drums 218bk, 218y, 218m, and 218c are charged scorotrons 221bk, 221y, and 221 connected to a high-voltage generator (not shown) of negative voltage.
It is uniformly charged by m and 221c. When the laser beam modulated by the recording signal is applied to the uniformly charged photoreceptor surface, the charge on the photoreceptor surface flows to the equipment ground of the drum main body due to a photoconductive phenomenon and disappears. here,
The laser light is prevented from blinking in a portion where the document density is high, and the laser light is turned on in a portion where the document density is low.

Thus, the photosensitive drums 218bk, 21
On the surfaces of 8y, 218m and 218c, the portion corresponding to the portion where the document density is high has a potential of, for example, -800V, and the portion corresponding to the portion where the document density is low has a potential of, for example, about -100V. That is, an electrostatic latent image is formed corresponding to the density of the document.

The electrostatic latent image is developed by a black developing unit 222bk, a yellow developing unit 222y, a magenta developing unit 222m, and a cyan developing unit 222c, respectively, and a photosensitive drum 218bk,
Black, yellow, magenta, and cyan toner images are formed on the surfaces of 218y, 218m, and 218c, respectively.

The black developing unit 222bk,
The toner in the yellow developing unit 222y, the magenta developing unit 222m, and the cyan developing unit 222c is charged to a positive potential by stirring. Further, the black developing unit 222bk and the yellow developing unit 222
y, a magenta developing unit 222m and a cyan developing unit 222c are provided with a developing bias generator (not shown).
, The toner adheres to a place where the surface potential of the photosensitive member is lower than the developing bias, and the original 1
01 is formed.

On the other hand, the recording paper stored in the transfer paper cassette 223 is fed out by the paper feeding operation of the feed roller 224, and is sent to the transfer belt 226 at a predetermined timing by the registration roller 225.

The recording paper placed on the transfer belt 226 is
The movement of the transfer belt 226 causes the photosensitive drums 218bk, 218y, 218m, and 218 as shown in FIG.
c sequentially pass through the lower portion of the photosensitive drums 218bk, 218bk, 2
18y, 218m and 218c, the charge scorotron 221bk,
221y, 221m and 221c, black,
The yellow, magenta, and cyan toner images are sequentially transferred onto recording paper.

Subsequently, the transferred recording paper is sent to a heat fixing unit 227 where the toner is fixed to the recording paper.
The recording paper is discharged to a tray 228. On the other hand, the residual toner generated on the photoreceptor surface after the transfer is transferred to the cleaner unit 22.
9bk, 229y, 229m and 229c.

The cleaner unit 229bk for collecting black toner and the black developing unit 222bk are connected by a toner collection pipe 230, and
The black toner collected at 9 bk is collected by the black developing unit 222 bk.

The cleaner units 229y and 229
m and 229c, the yellow, magenta and cyan toners collected from the recording paper
Since the toners of the different color developing units at the preceding stage of the cleaner units 229y, 229m and 229c are mixed due to, for example, reverse transfer to the 218m and 218c,
Do not collect for reuse.

The black developing unit 222bk,
The yellow developing unit 222y, the magenta developing unit 222m, and the cyan developing unit 222c include toner density sensors 231bk, 231y, 231m, and 231c, respectively.
Signals corresponding to the respective toner densities of 2bk, yellow developing unit 222y, magenta developing unit 222m, and cyan developing unit 222c are output to a toner density control unit (not shown).

The toner density control unit replenishes the toner consumed for toner image formation, and supplies the black developing unit 222bk, the yellow developing unit 222y,
In order to keep the toner densities of the magenta developing unit 222m and the cyan developing unit 222c constant, each of the toner density sensors 231bk, 231y, 231m and 23m
1c, the black developing unit 222bk, the yellow developing unit 222y, the magenta developing unit 222m, and the cyan developing unit 22
A toner supply signal for driving a toner supply motor (not shown) provided in 2c is output independently for each color.

The toner supply rollers 232bk, 232y, 232m and 232 are provided on the rotation shaft of each toner supply motor.
Each of the toner supply rollers c is fixed, and each toner supply roller is driven in accordance with the toner supply signal to supply toner to each developing unit.

The recording paper is moved from the photosensitive drum 218bk to 21.
The transfer belt 226 fed in the direction 8c is stretched around the idle roller 233, the drive roller 234, the idle roller 235 and the idle roller 236, and is driven to rotate counterclockwise by the drive roller 234.

The drive roller 234 is pivotally attached to the left end of a lever 238 pivotally attached to a shaft 237. Lever 238
A plunger 239 of a black mode setting solenoid (not shown) is pivotally connected to the right end of the plunger. A compression coil spring 240 is disposed between the plunger 239 and the shaft 237, and the compression coil spring 240 applies a clockwise rotational force to the lever 238.

When the black mode setting solenoid is not energized (color mode), the transfer belt 226 on which the recording paper is placed is moved to the photosensitive drums 218bk, 218y, 218m and 218m.
18c. In this state, a recording sheet is placed on the transfer belt 226, and all the photosensitive drums 218bk, 218y,
When toner images are formed on 218m and 218c, the toner images of the respective images are transferred onto the recording paper as the recording paper moves (color mode).

On the other hand, when the black mode setting solenoid is energized (black mode), the lever 238 rotates counterclockwise against the repulsive force of the compression coil spring 240, and the drive roller 234 is lowered by, for example, 5 mm, and the transfer is performed. The belt 226 is separated from the photosensitive drums 218y, 218m, and 218c, and remains in contact with the photosensitive drum 218bk. In this state, since the recording paper on the transfer belt 226 only comes into contact with the photosensitive drum 218bk, only the black toner image is transferred to the recording paper (black mode).

The recording paper is made of photosensitive drums 218y and 218.
m and 218c, so that no toner (residual toner) adheres to the photosensitive drums 218y, 218m and 218c on the recording paper, and no stain such as yellow, magenta and cyan appears. That is, in copying in the black mode, a copy similar to that of a normal single-color black copying machine is obtained.

Next, the operation timing of the main part of the copying mechanism will be described with reference to FIG. FIG. 5 is a timing chart when two identical full-color copies are made. When exposure scanning of the first carriage 207 is started,
First, the black density reference plate 241 and the white density reference plate 242 shown in FIG. 2 are read, and shading correction is performed based on the read densities.

Next, at substantially the same timing as the start of scanning of the document placing section, the modulation bias of the laser 116bk based on the recording signal is started, and the transfer belt 226 is moved by the distance of the lasers 116y, 116m and 116c. Travel time T
Modulation energization is started with a delay of y, Tm and Tc.
Each of the transfer chargers 243bk, 243y, 243m, and 243c is a semiconductor laser 116bk, 116y,
A predetermined time after the start of the energization of the modulators 116m and 116c (the laser irradiation positions on the photosensitive drum are the transfer chargers 243bk, 243y, 243m, and 243m).
(time to reach c).

Next, the console board 107 will be described with reference to FIG. FIG. 6 shows the appearance of the console board 107. The console board 107 includes a copy start key 601, a numeric keypad 602, and a clear stop key 60.
3, an interrupt key 604, a set number display 605, a copy number display 606, and a touch panel display 60
7 constitutes the appearance.

The touch panel display 607 is provided with a panel in which a number of transparent contact detection switches are arranged on the display screen of the display unit, and the display unit and the input unit are integrated. Specifically, selection of various operation modes, display of input guidance associated therewith, and display of the selected operation mode are performed by the touch panel display.

The touch panel display 607 can display a screen for selecting the type of document as shown in FIG. FIG. 7 is a view showing a display on the touch panel display 607 for selecting a document type.

Here, the standard display portion 701, the automatic display portion 702, and the designated display portion 703 are respectively provided in a standard processing mode for performing processing according to a standard color material, or
This is an area in which the processing of the color material is automatically determined and a processing mode suitable for the type is selected. The system control unit 106 detects the pressing of the display portion and enters each processing mode.

When the press of the copy start key 601 is detected in a state where the automatic processing mode is selected by pressing the automatic display portion 702, the system control unit 106 controls the reading processing unit 101 and the like to perform a normal original reading operation. At the same time, the read color gradation signals R, G, and B sampled by the sampling unit 102 are read, and the type of color material is determined. The type of the color material is determined by, for example, a method described in Japanese Patent Application Laid-Open No. 9-46533.

When the determination of the type of the color material is completed, the system control unit 106 sets the processing conditions determined in advance according to the determined type of the color material in the image processing unit 10.
Set to 3. The setting performed at this time is, for example, a change in a processing coefficient of a masking process performed by the color correction circuit 112 as a color correction processing unit.

The processing performed by the color correction circuit 112 is not limited to the masking processing, and can be applied to the case where interpolation processing and LUT (Look Up Table) are used. Also,
According to the determination of the type of the color material, it is possible to distinguish between a silver halide photo original and a halftone photo original. For example, when a color material used for a halftone photo original is detected, moire due to halftone dots is removed. Needless to say, such a setting as to add such a process is also possible.

Next, the system control unit 106 controls the copying operation according to the timing chart as shown in FIG. 5, and discharges the copy according to the setting of the image processing unit 103.

Next, the configuration and operation of the document illumination circuit of the digital copying machine according to the first embodiment will be described. FIG.
2 shows a schematic configuration of a document illumination circuit according to the first embodiment. FIG. 9 shows an example of a timing chart of the document illumination circuit of FIG. FIG. 10 shows a halogen lamp 20.
3A and 3B show average characteristics of the emission intensity distribution.

As shown in FIG. 8, the original illuminating circuit according to the first embodiment includes a halogen lamp 203 having a different color temperature.
a and 203b can be independently driven.

The original illumination circuit shown in FIG. 8 includes a halogen lamp 203a as an illumination source for illuminating the original, a halogen lamp 203b as an illumination source for illuminating the original, and an illumination driving circuit 401-1 for driving the halogen lamp 203a. When,
And illumination driving circuit 4 for driving halogen lamp 203b
01-2. The above halogen lamp 2
Numerals 03a and 203b function as document illuminating means of the first embodiment, and illumination driving circuits 401-1 and 401-2.
Has a function as illumination drive control means. The lighting drive circuits 401-1 and 401-2 are connected to the I / O port 12
1 is connected to the system control unit 106 and operates based on a signal from the system control unit 106.

In FIG. 8, the illumination drive circuits 401-1,
401-2, I / O from system control unit 106
A line synchronization signal Lsync as shown in FIG. 9A is input via the O port 121, and the illumination drive circuit 401
-1 is synchronized with the line synchronization signal Lsync,
As shown in (B), the halogen lamp 2 is driven by a binary drive current DrI-1 in which the current value Ia2 and the 0 level are switched for each line.
03a is driven. The illumination drive circuit 401-2 is
In synchronization with the line synchronization signal Lsync, the current value Ib2 and the 0 level are switched for each line as shown in FIG.
The halogen lamp 203b is driven by the drive current DrI-2 having the value. By performing such driving, the average color temperature T of the illumination light from the halogen lamps 203a and 203b becomes Ta2 for each line as shown in FIG.
(First spectral emission characteristic) and Tb2 (second spectral emission characteristic). Specifically, the halogen lamp 203a
Means that every time the drive current supplied from the illumination drive circuit 401-1 becomes Ia2, the average color temperature becomes Ta2, and the halogen lamp 203b operates every time the drive current supplied from the illumination drive circuit 401-2 becomes Ib2. In addition, the average color temperature is Tb
It becomes 2.

Then, in the system control unit 106, the read color tone signals R, G, B sampled are read and stored. In this case, the emission intensity distribution of the halogen lamps 203a and 203b has different characteristics as shown in FIG.
It is possible to obtain read color gradation signals R, G, and B sampled with illumination light having different emission intensity distributions for each line.

FIG. 10 shows a halogen lamp 203.
It is the figure which showed the relative light emission distribution of a and 203b. Since this change is peculiar to the type of color material of the document, that is, the spectral reflectance of the color material, the system control unit 106 compares and evaluates the degree of change with a prepared color material database, and The type of the color material can be determined.

In the timing of FIG. 9, the switching of the halogen lamps 203a and 203b is switched for each line. However, as shown in FIG. 11, the switching of the halogen lamps 203a and 203b is performed for every several lines. May be.

FIG. 11 shows another example of the timing chart of the original illumination circuit of FIG.

In this case, first, the illumination driving circuit 401-
1, 401-2 via the I / O port 121 from the system control unit 106, respectively.
Is input, and the illumination drive circuit 401-1 synchronizes with the line synchronization signal 103,
As shown in FIG. 11B, the current value is Ia once every four lines.
Binary drive current DrI- switching from 2 'to 0 level
1 drives the halogen lamp 203a. In addition, the illumination drive circuit 401-2 synchronizes with the line synchronization signal Lsync, as shown in FIG. 11C, to change the current value from 0 level to Ib2 'once every four lines.
The halogen lamp 203b is driven by I-2. By performing such driving, the halogen lamp 203 is driven.
The average color temperature T of the illuminating light according to FIGS.
As shown in (D), the average color temperature 20T is 1 in 4 lines.
Times, from Ta2 ′ (first spectral emission characteristic) to Tb2 ′ (second spectral emission characteristic).
(Spectral emission characteristic). That is, one to several lines
At different times, reading of different color separation characteristics is performed.

As described above, according to the first embodiment, the illumination driving circuits 401-1 and 401-2 use the halogen lamps 203a and 203b having different color temperatures, respectively, for each line or every several lines. Halogen lamp 2
The system control circuit 106 processes the read color gradation signals R, G, and B sampled by the sampling unit 102 to illuminate them by controlling the light sources 03a and 203b.
The type of the color material can be accurately determined by one reading.

The illumination source for illuminating the original is a halogen lamp 203a, 203b if the relative light emission distribution is different.
Not limited to this, a fluorescent lamp or the like may be used, and of course, different types such as a halogen lamp and a fluorescent lamp may be combined. Further, if three or more types of illumination sources having different light emission characteristics are used and the changes in the read color gradation signals R, G, and B are compared and evaluated, it is possible to determine the type of the color material with higher accuracy. It goes without saying that

[Embodiment 2] In the second embodiment, the halogen lamp 20 has the same configuration as that of the first embodiment.
Instead of 3a and 203b, a single halogen lamp 20
3, the document is irradiated with illumination light having different emission spectral characteristics in line units.

Next, the configuration and operation of the document illumination circuit of the digital copying machine according to the second embodiment will be described. FIG.
8 shows a schematic configuration of a document illumination circuit according to the second embodiment. FIG. 13 shows an example of a timing chart of the document illumination circuit of FIG. FIG. 14 shows the average characteristics of the emission intensity distribution of the halogen lamp 203.

The original illuminating circuit shown in FIG. 12 includes a halogen lamp 203 as original illuminating means for illuminating the original, and an illumination driving circuit 401 as illumination driving control means for driving the halogen lamp 203. The illumination drive circuit 401 is connected to the system control unit 106 by the I / O port 121, and operates based on a signal from the system control unit 106.

In FIG. 12, a line synchronization signal Lsync as shown in FIG. 13A is input to the illumination drive circuit 401, and the illumination drive circuit 401 outputs the line synchronization signal Lsync.
In synchronization with the current values Ia1 and Ib as shown in FIG.
The halogen lamp 203 is driven by a binary drive current DrI that switches between 1 and 1 for each line. By performing such driving, the halogen lamp 203 is turned on as shown in FIG.
As shown in (C), the average color temperature T is Ta1 for each line.
(First spectral emission characteristic) and Tb1 (second spectral emission characteristic).

Then, in the system control unit 106, the sampled read color gradation signals R, G, and B are read and stored. In this case, the emission intensity distribution of the halogen lamp 203 has different characteristics as shown in FIG. 14 depending on the level of the drive current.
It is possible to obtain read color gradation signals R, G, and B sampled with illumination light having different emission intensity distributions for each line.

FIG. 14 is a diagram showing a light emission intensity distribution depending on the difference in the magnitude of the driving current applied to the halogen lamp 203. Since this change is peculiar to the type of color material of the document, that is, the spectral reflectance of the color material, the system control unit 106 compares and evaluates the degree of change with a prepared color material database, and The type of the color material can be determined.

At the timing shown in FIG. 13, the level of the driving current applied to the halogen lamp 203 is switched for each line to emit light with a different emission intensity distribution for each line. However, as shown in FIG. Lamp 2
03 may be switched every several lines.

FIG. 15 shows another example of the timing chart of the document illumination circuit of FIG.

First, the illumination drive circuit 401 has the configuration shown in FIG.
A line synchronization signal Lsync as shown in (A) is input, and the illumination drive circuit 401 synchronizes with the line synchronization signal Lsync,
As shown in FIG. 15B, once every four lines, the current value is I
binary drive current DrI switching from a1 'to Ib1'
Drives the halogen lamp 203. By performing such driving, the halogen lamp 203 is turned on as shown in FIG.
As shown in FIG. 5 (C), the average color temperature T is once every four lines,
Switching from Ta1 '(first spectral emission characteristic) to Tb1' (second spectral emission characteristic). That is, reading of different color separation characteristics is performed once every several lines.

As described above, according to the second embodiment, the illumination driving circuit 401 uses the halogen lamp 203 having different light emission distribution characteristics depending on the magnitude of the applied driving current.
However, the level of the drive current applied to the halogen lamp 203 is alternately changed for each line or every few lines, and the emission distribution intensity of the halogen lamp 203 is changed for every line or every several lines, thereby controlling the system. The circuit 106 processes the read color gradation signals R, G, and B sampled by the sampling unit 102, thereby
The type of the color material can be determined with high accuracy by reading the number of times. Also, as in the second embodiment, when the original illumination source (halogen lamp 203) is used in common and only the driving method of the original illumination source is switched, the number of parts of the original illumination circuit can be reduced, and the original illumination circuit can be used. There is an advantage if it can be realized at low cost.

The illumination source for illuminating the original is not limited to the halogen lamp 203 as long as the intensity of the light emission distribution is different. Further, if the drive current is set to three values or more, and three or more types of light emission distribution intensities are used to compare and evaluate the changes in the read color gradation signals R, G, and B, a more accurate color material can be obtained. Needless to say, the type can be determined.

[Embodiment 3] In the third embodiment, a halogen lamp 20 having a configuration substantially similar to that of the first embodiment is used.
The light emission driving circuit 401-
Instead of switching on a line basis of the original according to 1, 401-2, the spectral transmission characteristic is switched by an optical filter.

That is, in the third embodiment, an optical filter as an optical filter means is used in order to make the spectral transmission characteristics of illumination light from a halogen lamp as original illuminating means or reflected light from an original different for each line of the original. 302,
And a motor 303 and a motor control circuit 304 as optical filter driving means.

FIG. 16 shows a schematic configuration of a filter switching device of a digital copying machine according to the second embodiment.
FIG. 17 shows the spectral transmission characteristics of the optical filter 302.

The filter switching device shown in FIG. 16 employs two types of optical filters 301-1 having different spectral transmission characteristics from each other.
Optical filter 3 including optical filter 1 and optical filter 301-2
02 and a motor 30 for driving the optical filter 302 to rotate.
3 and a motor control circuit 304 for driving the motor 303
It is composed of

The optical filter 302 comprises a substantially semi-elliptical optical filter 301-1 and a substantially semi-elliptical optical filter 3
The optical filter 301-1 and the optical filter 301-2 respectively have a spectral transmission characteristic (a first spectral transmission characteristic and a second spectral transmission characteristic) as shown in FIG. Transmission characteristics). Further, the optical filter 301 includes halogen lamps 203a and 203b.
Between the optical path between the document and the document, or between the document and the CCD 108r, 1
08g and 108b are inserted between the optical paths.

In FIG. 16, a line synchronization signal Lsync is input to a motor control circuit 304, and the motor control circuit 304 drives a motor 403 in synchronization with the line synchronization signal Lsync to drive an optical device arranged in an optical path. Filter 30
2 is rotated so that light (illumination light from a halogen lamp or light reflected from a document) passes alternately through the optical filters 301-1 and 301-2 in line units. , Or the spectral transmission characteristics of the reflected light from the original are made different for each line of the original (the first spectral transmission characteristic and the second spectral transmission characteristic are switched).

Then, in the system control unit 106, the sampled read color gradation signals R, G, and B are read and stored. In this case, the spectral transmission characteristics of the optical filters 301-1 and 301-2 through which light passes have characteristics as shown in FIG.
The read color gradation signal R, sampled with illumination light having different spectral transmittance or reflected light having different spectral transmittance,
G and B can be obtained.

Since this change is peculiar to the type of color material of the document, that is, the spectral reflectance of the color material, the system control is performed by comparing and evaluating the degree of change with a prepared color material database. The unit 106 can determine the type of the color material.

The spectral transmission characteristics of the optical filter 302 may be switched for each line of the document or for every several lines. Further, the spectral transmittance characteristics of the optical filter that can be inserted may be three or more types. If the changes of the read color gradation signals R, G, and B are compared and evaluated, respectively, the type of the color material with higher accuracy can be improved. Of course can be determined.

As described above, according to the third embodiment, the optical filter 302 having a plurality of spectral transmission characteristics is disposed between the light path between the halogen lamp and the original or between the light path between the halogen lamp and the CCD. Control circuit 404
Drives the optical filter 302 to vary the spectral transmission characteristics of the illumination light from the halogen lamp or the reflected light from the original for each line of the original, and the system control circuit 10
6 processes the read color gradation signals R, G, and B sampled by the sampling unit 102, so that the type of the color material can be accurately determined by one reading.

By the way, the first to the fifth embodiments explained above.
In the case where the image signal of the original is read with different color separation characteristics for each line as in 3, even if the output signal level of the CCD at the time of reading the same color, for example, a white reference plate, is at the same pixel position. , May change with the switching of the color separation characteristics. This change can be ignored,
More preferably, it is better to add correction.

[Fourth Embodiment] In the fourth embodiment, in the configuration of any of the first to third embodiments, the shading correction circuit 110 shown in FIG. This is a configuration for correcting a change in signal level.

FIG. 18 shows a schematic configuration of a shading correction circuit 110 of a digital copying machine according to the fourth embodiment.

The shading correction circuit shown in FIG.
An adjusting circuit 402 for outputting an image signal obtained by shading-correcting an input image signal; and a line memory for storing one line each of reference image data obtained by reading a white reference plate with different (two) color separation characteristics. 403
-1, 403-2.

In FIG. 18, the adjusting circuit 402
The output signals of the CDs 108r, 108g, 108b are A / D
A / D converters 109r, 109g and 109b respectively
The image signal 404 obtained by the conversion is input, and the I / O port 12 is input from the system control unit 106.
1, a line synchronization signal Lsync is input. When the reading of the document portion is started, the adjustment circuit 402 selects the memory 403-1 or 403-2 in synchronization with the switching of the color separation characteristics described above, and the memory 403-1 in synchronization with the line synchronization signal Lsync. Alternatively, reading of the reference image data stored in 403-2 is started. Then, the input image signal 401 is subjected to shading correction according to the read reference image data, and a read color gradation signal (R, G, B) 405 subjected to shading correction is output.

Then, in the system control unit 106, the read color tone signals R, G, B sampled are read out and stored respectively. In this case, image signals having different color separation characteristics are read out from the original in line units, and shading correction is performed according to the color separation characteristics. Therefore, shading correction is performed in line units according to the color separation characteristics. The read color gradation signals R, G, B can be obtained. The system control unit 106 determines the type of the color material based on the read color gradation signals R, G, B.

As described above, according to the fourth embodiment, the shading correction circuit 101 performs shading correction different for each color separation characteristic on an image signal obtained by reading a document with different color separation characteristics for each line. When the same color as that of the white reference plate is read, the read color gradation signals RGB can be made the same even if the color separation characteristics change, and a high-quality image signal can be output.

When the color separation characteristics are changed, the absolute amount of the incident light may change greatly, and the output signal level of the CCD may also change greatly. In such a case, it is more desirable to change the amplification factor of the CCD output signal in synchronization with the switching of the color separation characteristics described above.

[Fifth Embodiment] In the fifth embodiment, in the configuration of any of the first to fourth embodiments, a document is read from an image signal obtained by reading a document with different color separation characteristics for each line. A specific method for determining the type of is described. In the fifth embodiment, the type of a document is determined by a hardware circuit shown in FIG. 19 instead of the system control unit 106 shown in FIG.

FIG. 19 shows a schematic configuration of a document type determination circuit of a digital copying machine according to the fifth embodiment.

The original type determination circuit shown in FIG. 19 converts the input RGB image signal (read color gradation signal) 502-1 to one.
A line buffer 501-1 for storing an image signal and outputting an image signal delayed by one line, and a line buffer 501-1
A line buffer 501-2 for storing one line of the RGB image signal 502-2 input from the CPU and outputting an image signal 502-3 delayed by one line, and converting the image signal 502-1 and the image signal 502-3 to the RGB. An interpolation circuit 504 as interpolation means for outputting an image signal obtained by averaging for each color as an interpolation signal 505; an image signal 502-2 and an image signal 5;
05, and a determination circuit 506, which is a document type determination means for determining the type of the document based on the image signal
2 and a selection circuit 508 for selecting the interpolation signal 505 and outputting it as an image signal 509.

The line buffer 501-1 receives the line synchronization signal Lsync and the RGB image signal 502-1. The line buffer 501-1 receives the line synchronization signal Lsy.
The image signal 502-2 delayed by one line with respect to the image signal 502-1 in synchronization with nc is transferred to the line buffer 501-2.
And to the determination circuit 506. The line buffer 501-2 receives the line synchronization signal Lsync and the image signal 502-2 from the line buffer 502-1. The line buffer 501-2 synchronizes with the line synchronization signal Lsync and outputs the image signal 502- An image signal 502-3 which is delayed by one line with respect to 2, that is, delayed by two lines with respect to the RGB image signal 502-1 is output to the interpolation circuit 504. The interpolation circuit 504 includes an RGB image signal 502
-1 and the image signal 502-3 are input and the interpolation circuit 50
4 is an RGB image signal 502-1 and an image signal 502-3.
Are averaged for each color to obtain an interpolation signal 50.
5 is output to the determination circuit 506 and the selection circuit 508.

Here, the input image signal 502-1
Are image signals obtained by reading a document with different color separation characteristics (first color separation characteristics and second color separation characteristics) alternately for each line as shown in FIGS. In this case, the interpolation signal 505 output by the interpolation circuit 504 can be regarded as an image signal when the same line as the image signal 502-2 is read with different color separation characteristics from the image signal 502-2. In other words, it can be considered that prediction is made by the method of averaging from the image signals 502-1 and 502-3 of the lines before and after the line read with different color separation characteristics. In other words, the image signal of the line of the original read with the second color separation characteristic is replaced with the image signal of the line of the original read with the first color separation characteristic and output as an interpolation signal.

The judgment circuit 506 includes the line synchronization signal 50
3, the image signal 505 output from the interpolation circuit 504, and the image signal 502 output from the line buffer 501-1.
-1 is input. That is, the judgment circuit 506 includes:
Image signals obtained by reading the same portion of the document with different color separation characteristics are input. The determination circuit 506 determines the type of the document based on the image signal 502-2 and the interpolation signal 505, and outputs a determination signal indicating the type of the document. Therefore, the determination circuit 506 can determine the type of the document by processing these two types of RGB image signals. The method of determining the type of the original is described in, for example,
Use the method disclosed in US Pat. In making the determination, the line synchronization signal Lsync is referred to
The color separation characteristics of each image signal are used to identify the original. Image processing is switched by the determination signal 507 output from the determination circuit 506.

The selection circuit 508 outputs the image signal 5 if the image signal 502-2 is an image signal read with the first color separation characteristic.
02-2 is selected and output as an image signal 509, and if the image signal 502-2 is an image signal read with the second color separation characteristic, the interpolation signal 505 is selected and output. This selection is made in synchronization with the line synchronization signal Lsync.

In the first to third embodiments, the original is read with different color separation characteristics (first and second color separation characteristics), but the image signal when the original is read with the second separation characteristic is read. May deteriorate in relative quality. Specifically, for example, as shown in FIG. 12, when the drive current DrI of the halogen lamp 203 is changed, the light emission energy of the halogen lamp 203 is reduced by reducing the current value. , CCD108
The outputs of r, 108g, and 108b become smaller, the noise component relatively increases, and the quality of the image signal deteriorates. If this deterioration is severe, it will affect the final output image.
The effect can be reduced by reducing the ratio of reading of the original in the color separation characteristics.

That is, in the fifth embodiment, the image signal read with the second color separation characteristic is used only for document type determination, and for the final image output, the first and second color separation characteristics before and after it are used. Since the image signal predicted from the read image signal is used, the image signal can be output without using the image signal of deteriorated quality such as the second color separation characteristic, and the color separation characteristic can be switched. The effect on the final image signal caused by the above can be eliminated.

When the color separation characteristics are switched every several lines, the judgment signal 507 output from the judgment circuit 506 is output.
Is correct once every few lines. Therefore, in the lines before and after the line, the judgment signal of the correct line is expanded and used. It should be noted that since the type of the document does not change abruptly on the document, even if the determination result for every several lines is used as described above, it hardly affects the final output image. For the same reason, the original type determination in the line direction may be performed in units of several pixels. In this case, it is also possible to adopt a method in which the final determination is determined by majority decision using the determination results of the peripheral pixels.

When any one of the above-described first to fifth embodiments or a combination is added, the characteristics of the image signal change with the switching of the color separation characteristics. This change can be made to a negligible level by smoothing or the like, but it is more preferable to individually correct the change.

[Sixth Embodiment] In the sixth embodiment, in any one of the first to fifth embodiments, the change in the characteristics of the image signal is separately corrected according to the switching of the color separation characteristics. A specific method for this will be described.

FIG. 20 shows a schematic configuration example of a characteristic correction circuit of a digital copying machine according to the sixth embodiment. This characteristic correction circuit corresponds to the gamma correction circuit 111 and the color correction circuit 112 in FIG.

The characteristic correction circuit shown in FIG. 20 is a gamma correction circuit 602 for correcting the R component of the input read color gradation signal.
1 and a gamma correction circuit 6 for correcting the G component of the read color gradation signal
02-2, a gamma correction circuit 602-3 for correcting the B component of the read color gradation signal, and a color correction circuit 605 for performing color correction by switching correction contents in synchronization with switching of color separation characteristics. Have been.

The gamma correction circuits 602-1, 601-2, and 601-3 receive the line synchronization signal Lsync and the R component 601-1 and the G component 6 of the read color gradation signal.
01-2 and B component 601-3 are input. Gamma correction circuits 602-1, 602-2, and 602-
3 has a memory table for converting the value of the image signal of each color, and corrects γ of the image signal using this memory table. In this case, the γ correction circuit 6
02-1, 602-2, and 602-3 switch the correction contents in synchronization with the line synchronization signal Lsync, that is, in synchronization with the switching of the color separation characteristics.

The line correction signal Lsync is input to the color correction circuit 605, and the gamma correction circuit 602-
1, 602-2, and 602-3 output an R component 604-1, a G component 604-2, and a Y component 604-
3 are input. The color correction circuit 605 is provided for each color component 604-1, 604-2, 60 of the input image signal.
This is a circuit for correcting the correlation of 4-3.
, And color correction is performed by performing a matrix operation or the like, and image signals 606-1, 606-2, and 606-3 of the respective colors after the color correction.
Is output. In this case, the color correction circuit 605 uses the above γ
Similarly to the correction circuits 602-1, 602-2, and 602-3, the correction contents are switched in synchronization with the line synchronization signal Lsync, that is, in synchronization with the switching of the color separation characteristics.

As described above, according to the characteristic correction circuit in the sixth embodiment, the gamma correction circuits 602-1 and 602-1
2-2 and 602-3 correct the γ values of the R, G, and Y components of the image signal by switching the correction contents in synchronization with the switching of the color separation characteristics. γ
Each color component 604-1, 604- of the corrected image signal
Since the correlation between 2,604-3 is corrected by switching the correction contents in synchronization with the switching of the color separation characteristics, the characteristics of the image signal generated by the switching of the color separation characteristics are optimally corrected. Therefore, a high-quality image signal can be output. The gamma correction circuit 602-
The effects of the correction by 1, 602-2 and 602-3 can be obtained to some extent by the shading correction circuit of FIG.

[0134]

As described above, according to the first aspect of the present invention, the original illuminating means comprising a plurality of illumination sources which can be driven independently and have different spectral emission characteristics from each other; Drive each of the illumination sources independently
Illumination drive control means for switching and controlling the spectral emission characteristics of the original illuminating means for each original line, color separation means for color-separating reflected light from the original illuminated by the original illuminating means, and color separation means for color separation. Image reading means for receiving the decomposed reflected light, photoelectrically converting the received light, and reading it as an image signal, and document type determining means for determining the type of the document based on the image signal read by the preceding image reading means As a result, it is possible to output an image signal obtained by reading a document with different color separation characteristics for each line, and to provide a low-cost image reading apparatus capable of discriminating the type of a document in a short time. Become.

According to the second aspect of the present invention, there is provided an original illuminating means comprising a single illumination source for irradiating the original with light;
Illumination drive control means for controlling the drive by switching the spectral emission characteristics of the original illuminating means line by line of the original, color separating means for color separating reflected light from the original illuminated by the original illuminating means, and color separating means Image reading means for receiving reflected color-separated light, photoelectrically converting the received light, and reading it as an image signal, and document type determining means for determining the type of the document based on the image signal read by the image reading means Therefore, it is possible to output an image signal obtained by reading a document with different color separation characteristics for each line, and it is possible to provide a low-cost image reading apparatus capable of discriminating a document type in a short time. . In addition, since a single document illuminating means is used, the cost of the document illuminating means can be reduced.

According to the third aspect of the present invention, the document illuminating means for irradiating the original with light and the light path between the document illuminating means and the original, or the light path between the document illuminating means and the photoelectric conversion means. A plurality of optical filter units having a plurality of spectral transmission characteristics, and driving the optical filter unit to vary the spectral transmission characteristics of illumination light from the original illuminating unit or reflected light from the original for each line of the original. Optical filter driving means, color separation means for color-separating the reflected light from the document illuminated by the document illuminating means, receiving the reflected light color-separated by the color separation means, photoelectrically converting the light, and reading it as an image signal Since the image reading unit and the document type determining unit that determines the type of the document based on the image signal read by the image reading unit are provided, different color separation characteristics are provided for each line. Can output an image signal obtained by reading the document, it is possible to provide a discernible cost image reading apparatus of the document type in a short time of processing. In addition, since the color separation characteristics are made different by using an optical filter, the image reading apparatus can have a simple configuration.

According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, a shading correction for performing a different shading correction for each line on the image signal read by the image reading means. Means for judging the type of the document based on the image signal subjected to shading correction by the shading correction means. It is an ability to provide an image reading apparatus capable of outputting a high-quality image signal while eliminating unevenness in correction characteristics.

According to a fifth aspect of the present invention, in the image reading apparatus according to the first, second, or fourth aspect, the illumination drive control means alternately operates the original illumination means for each line. Is switched between the first spectral emission characteristic and the second spectral emission characteristic, it is possible to obtain an image signal read by illumination having different spectral emission characteristics for each line.

According to a sixth aspect of the present invention, in the image reading apparatus according to the first, second, or fourth aspect, the illumination drive control means is provided for every one to N (N> 1) lines. In this configuration, the spectral emission characteristics of the document lighter are alternately switched between the first spectral emission characteristics and the second spectral emission characteristics, so that an image signal read with illumination having different spectral emission characteristics for each of a plurality of lines can be obtained. Becomes possible.

According to a seventh aspect of the present invention, in the image reading device according to the third or fourth aspect, the optical filter driving means alternately changes the spectral transmission characteristics of the optical filter means for each line. Is switched between the first spectral transmission characteristic and the second spectral transmission characteristic, it is possible to obtain image signals having different spectral transmission characteristics for each line.

In the image reading apparatus according to the eighth aspect, in the image reading apparatus according to the third or fourth aspect, the optical filter driving means may have a ratio of 1: N (N> N).
1) Since the configuration is such that the spectral transmission characteristic of the optical filter means is switched between the first spectral transmission characteristic and the second spectral transmission characteristic alternately for each line, it is possible to obtain image signals having different spectral transmission characteristics for each of a plurality of lines. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a block diagram of a digital copying machine to which a color image input device according to a first embodiment is applied.

FIG. 2 is an explanatory diagram showing a basic configuration and operation of the digital copying machine according to the first embodiment.

FIG. 3 is an explanatory diagram showing detection of a home position sensor according to the first embodiment.

FIG. 4 is an explanatory diagram showing a laser scanning system of the cyan recording device according to the first embodiment.

FIG. 5 is an explanatory diagram showing a timing chart when two identical full-color copies are created according to the first embodiment;

FIG. 6 is an explanatory diagram illustrating an appearance of the console board according to the first embodiment.

FIG. 7 is an explanatory diagram showing a display for selecting a document type on the touch panel display according to the first embodiment;

FIG. 8 is a diagram illustrating a schematic configuration of a document illumination circuit according to the first embodiment;

FIG. 9 is a diagram illustrating an example of a timing chart of the document illumination circuit of FIG. 8;

FIG. 10 is a diagram showing an average characteristic of a light emission intensity distribution of the halogen lamp in the first embodiment.

11 is a diagram showing another example of the timing chart of the original illumination circuit of FIG. 8;

FIG. 12 is a diagram illustrating a schematic configuration of a document illumination circuit according to a second embodiment;

FIG. 13 is a diagram illustrating an example of a timing chart of the document illumination circuit in FIG. 12;

FIG. 14 is a diagram showing an average characteristic of a light emission intensity distribution of the halogen lamp according to the second embodiment.

FIG. 15 is a diagram showing another example of the timing chart of the document illumination circuit of FIG. 12;

FIG. 16 is a diagram showing a schematic configuration of a filter switching device according to a third embodiment.

FIG. 17 is a diagram showing the spectral transmission characteristics of the optical filter according to the third embodiment.

FIG. 18 is a diagram illustrating a schematic configuration of a shading correction circuit according to a fourth embodiment;

FIG. 19 is a diagram illustrating a schematic configuration of a document type determination circuit according to a fifth embodiment;

FIG. 20 is a diagram illustrating a schematic configuration example of a characteristic correction circuit according to a sixth embodiment;

[Explanation of symbols]

101, 1701 Read processing unit 102, 1702 Sampling unit 103 Image processing unit 104 Image recording unit 105 Synchronous control unit 106 System control unit 107 Console board 108r, 108g, 108b, 1503 CCD 109r, 109g, 109b, 1704 A / D converter 110, 1705 Shading correction circuit 111 Gamma correction circuit 112 Color correction circuit 113 Scaling processing circuit 114 Dither processing circuit 115c, 115m, 115y Buffer memory 116c, 116m, 116y, 116bk Semiconductor laser 117c, 117m, 117y, 117bk Laser driver 203a, 203b, 1001, 1002 Halogen lamp 206 Dichroic prism 302, 302-1, 302-2 Optical lens 401, 401-1, 401-2 Illumination drive circuit 402 Adjustment circuit 403-1, 403-2 Line memory 501-1, 501-2 Line buffer 504 Interpolation circuit 506 Judgment circuit 508 Selection circuit 602-1, 602 2,602-3 γ correction circuit 605 Color correction circuit 607 Touch panel display 701 Standard display part 702 Automatic display part 703 Designated display part

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 1/401 H04N 1/40 101A 1/46 1/46 Z

Claims (8)

[Claims] Claims: 1. Each can be driven independently, and
An original illuminating unit having a plurality of illumination sources having different spectral emission characteristics, and an illumination for driving and controlling each of the plurality of illumination sources independently by switching the spectral emission characteristics of the original illuminating unit for each original line. Drive control means, color separation means for color-separating the reflected light from the document illuminated by the document illuminating means, and an image which receives the reflected light color-separated by the color separation means, photoelectrically converts the light, and reads it as an image signal An image reading apparatus comprising: a reading unit; and a document type determining unit that determines a type of a document based on an image signal read by the image reading unit. 2. A document illuminating means comprising a single illumination source for irradiating light to a document, a drive control means for switching and controlling a spectral emission characteristic of the document illuminating means for each line of the document, Color separation means for color-separating the reflected light from the original illuminated by the illumination means, image reading means for receiving the reflected light color-separated by the color separation means, photoelectrically converting the received light, and reading it as an image signal; And a document type determining means for determining the type of the document based on the image signal read by the means. 3. A document illuminating unit for irradiating a document with light, and a plurality of spectral transmission units disposed between an optical path between the document illuminating unit and the document or between an optical path between the document illuminating unit and the photoelectric conversion unit. Optical filter means having characteristics; and optical filter driving means for driving the optical filter means to vary the spectral transmission characteristics of illumination light from the document illuminating means or reflected light from the document for each line of the document. Color separation means for color-separating the reflected light from the document illuminated by the document illuminating means, image reading means for receiving the reflected light color-separated by the color separation means, photoelectrically converting the received light, and reading it as an image signal; An image reading device comprising: a document type determination unit that determines a type of a document based on an image signal read by the image reading unit. 4. A shading correction means for performing a different shading correction for each line of a document on an image signal read by said image reading means, wherein said document type determination means is an image which is subjected to shading correction by said shading correction means. The image reading apparatus according to claim 1, wherein the type of the document is determined based on a signal. 5. The apparatus according to claim 1, wherein said drive control means alternately switches the spectral emission characteristic of said document illuminating means between a first spectral emission characteristic and a second spectral emission characteristic for each line. 5. The image reading device according to 2 or 4. 6. The driving control means includes one to N (N> 1).
5. The image reading apparatus according to claim 1, wherein a spectral emission characteristic of the document illuminating unit is switched between a first spectral emission characteristic and a second spectral emission characteristic alternately for each line. 7. The optical filter driving means according to claim 3, wherein said optical filter driving means alternately switches a spectral transmission characteristic of said optical filter means between a first spectral transmission characteristic and a second spectral transmission characteristic. Or the image reading device according to 4. 8. The optical filter driving means includes: one-to-N
5. The image reading apparatus according to claim 3, wherein the spectral transmission characteristic of the optical filter unit is switched between a first spectral transmission characteristic and a second spectral transmission characteristic alternately for each (N> 1) line. .