JPH0576823B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a color image reading device used for inputting image data in devices that electrically handle image information, such as digital copying machines, facsimiles, and electronic files. 2. Description of the Related Art Line sensors are known in which a plurality of light receiving elements are arranged in a line across the width of a document to be read in order to photoelectrically read the density of a document image. now,
If you want to read the width direction (approximately 210 mm) of an A4 size document at the same size with a resolution of 16 pixels/mm, approximately
1 with approximately 3,500 light receiving elements on a 300mm substrate
Requires a book line sensor. However, it is difficult to arrange such a large number of light receiving elements on the same substrate without missing them.
Moreover, it is difficult to form a film with substantially uniform sensitivity, and therefore, it is not practical in terms of cost unless improvements are made in yield and the like. Therefore, it is conceivable to arrange a plurality of line sensors each consisting of approximately 1000 light receiving elements in the scanning direction and read one line of image by dividing it with each line sensor. In this way, the number of light receiving elements to be formed on the same substrate is not so large.
Yield can be improved and the above-mentioned cost problems associated with it can be solved to some extent. However, there are invalid bits at both ends of the line sensor that cannot be used for image reading, and therefore, when a plurality of line sensors are arranged on one line, an unreadable area occurs. Therefore, it is conceivable to arrange a plurality of line sensors in a staggered manner, for example, so that the reading lines of adjacent line sensors are different. When multiple line sensors are arranged in a staggered manner,
Adjacent line sensors scan different document surfaces by moving relative to each other in a direction perpendicular to the scanning direction. 2
A time lag occurs between the signals from the line sensors in the column, which corresponds to the positional lag between adjacent line sensors. In a copying apparatus that requires high resolution such as 16 pixels per mm, it is undesirable for the copy image to be affected by the shift in reading. In addition, when reading color images,
This shift also affected color balance. In addition, when reading a document image at variable magnification using line sensors arranged in a staggered manner in this way,
The time from when the line sensor in the first row reads the same line to when the line sensor in the second row reads it varies depending on the magnification ratio, and it is difficult to correct this time difference, so it is difficult to perform magnification reading as desired. I couldn't do it. The present invention has been made in view of the above points, and an object of the present invention is to read color originals satisfactorily with high resolution and at any reading magnification. a reading unit in which a plurality of line sensors share one line on a document, and adjacent line sensors read different lines on the document; a moving means that relatively moves in a direction perpendicular to the scanning direction of the sensor at a speed according to the reading magnification; and a moving means that is provided corresponding to each of the plurality of line sensors, and is provided to move the plurality of objects generated by each of the plurality of line sensors. A plurality of separation means for separating color component signals for each color component; and a plurality of separation means provided corresponding to each of the color component signals of a plurality of colors, and outputs from line sensors that read the document in advance and read the document in advance of the document. a plurality of forming means for forming continuous color component signals of one line of a plurality of colors for each color component by delaying the output from a line sensor to be read; The present invention provides a color image reading device having a setting means for setting a delay amount with respect to an output from a line sensor to be read in accordance with the reading magnification. Next, embodiments of the invention will be described with reference to the drawings. In this embodiment, a color contact sensor is used to read the original. Figures 1a and 1b show the configuration of a reading section using this color contact sensor.
As shown in FIG. 1a, there is a sensor unit 11 equipped with a plurality of CCD chips, a convergent rod lens array 12 disposed on the sensor unit 11, and a convergent rod lens array 12 provided near the side surface of the convergent rod lens array 12. and a linear light source 13 form an integral structure. However, in Figure 1a, the linear light source is 1
Although only one lens is shown, one more lens is actually provided so as to sandwich the rod lens array 12. With this configuration, the converging rod lens array 12 can be used to provide a plurality of lenses in a one-to-one relationship without reducing the reflected light from the document irradiated by the light source 13 in any way.
Combined on CCD chip. The sensor unit 11, the converging rod lens array 12, and the light source 13 are connected to a signal processing board 16 and a flexible electric wire 1 connecting the sensor unit 11 and the signal processing board 16, as shown in FIG.
5 is mounted on the moving body 14, and further,
A flexible electric wire 17 is used to connect the movable body (original scanning unit) 14 and the main body. As described above, the CCD of sensor unit 11 is
The optical image formed on the chip is converted into electric charge by the photoelectric conversion capability of the CCD. This charge is sequentially transferred by the charge transfer ability of the CCD and becomes an image signal. Each part will be explained in detail. The contact type color CCD sensor unit 11, as shown in FIG.
Five CCD chips 21 to 2 arranged in a staggered pattern
5, a cover 27 covering the ceramic substrate 26, and flexible electric wires 28a to 28f for connection. CCD
In chips 21 to 25, the light receiving part consists of a p-n photodiode, and the size of the light receiving part is 62.5 μm×
15.5μm, and the photosensitive pixel is a 12-bit blank pixel that is not connected to the photosensitive pixel as shown in Figure 4.
24-bit light shield pixels D13-D36 shielded by D1-D12Al, 36-bit dummy pixels D37-D72, 3072-bit effective signal pixels S1-
It consists of a total of 3168-bit light receiving section including S3072 and 24-bit rear end dummy pixels D73 to D76. Further, as described above, the CCD chips 21 to 25 are arranged in two rows in a staggered manner as shown in FIG. In this case, adjacent CCD chips, for example CCD chips 22 and 23, are provided with a distance l between the centers of their light receiving sections in the sub-scanning direction, as shown in FIG. Also, these CCD chips 2
1 to 25 are arranged so as to overlap with each other along the arrangement direction (main scanning direction). In this embodiment, the center distance l is a distance of four pixels. As mentioned above, the light receiving sections of the CCD chips 21 to 25 are, from the left end, empty feed areas D1 to D12, light shield areas D13 to D36, dummy areas D37 to D72, effective pixel areas S1 to 3072, and rear end dummy areas D73 to D96. The pixels are arranged in such a way that they overlap each other using the areas excluding the 3072-bit effective pixel areas S1 to S3072. As a result, the effective reading area is 320 mm, which is slightly longer than the short width of A3 size 297 mm. It is necessary to arrange color filters on the light receiving sections (photodiodes) of the CCD chips 21 to 25 in order to receive color signals. There are two methods for this: one method is to bond the color filter and the Si element, which is a photodiode, with an adhesive, and the other method is to stack the color filter directly on the Si element. In the former case, the color filter can be fabricated on a glass substrate, but an extra step of adhesion is required when combining it with the Si element, and alignment errors are likely to occur. It is quite difficult to suppress this adhesion error to a few μm or less, which may cause deterioration of color reproducibility and shading characteristics. On the other hand, in the latter case, a color element is completed by simply manufacturing color filters to match the pixels of the Si element, so the process is extremely simple and alignment accuracy can be greatly improved. Therefore, the color filter of the CCD chip used in this embodiment is of the latter type. Next, a specific filter arrangement will be explained.
In this embodiment, three color filters of yellow (Ye), green (G), and cyan (Cy) are arranged repeatedly in this order as shown in Fig. 5, and three adjacent bits constitute one pixel during reading. ing. Al outside the filter
is shielded by. The spectral characteristics of these color filters are shown in FIG. As is clear from FIG. 6, the transmittance of the Ye filter increases rapidly from around 500 nm, as shown by curve 61. Cy filter transmittance is curve 6
As shown in 2, it shows a peak around 500 nm. In this example, the G filter is obtained by superimposing a Cy filter and a Ye filter, so the transmittance has a peak near 500 nm, as shown by curve 63. An important point in the spectral characteristics of these filters is that they
The point is that the transmittance does not become zero even for wavelengths of about 700 nm. Here, color filters and CCD chips 21 to 25
must function similarly to the human eye in order to achieve faithful color reproduction. As shown in FIG. 7, the spectral characteristics of the light-receiving parts of CCD chips 21 to 25 reach a maximum at a wavelength of about 550 nm.
It has a finite relative sensitivity up to 1000 nm or more. In other words, the color filter in this example is
The light-receiving part of the CCD chip responds even to light with a wavelength of 700 nm or more. In contrast, the visibility of the human eye is zero for wavelengths of 700 nm or more. Therefore, simply CCD chip and Cy,
The combination of G and Ye color filters alone cannot perform the same functions as the human eye. Therefore, in this embodiment, the light source is specified as described later. Next, the focusing rod lens array 12 will be explained. As shown in FIG. 8, the focusing rod lens array 12 in this embodiment has an original surface 81 at the focal length on the light incident side, and two rows at the focal length on the exit side.
A CCD chip array 82 is present. By setting in this way, the document surface 81 and the CCD chip row 8
2 is related to imaging. That is, the image on the document surface 81 is formed on the CCD chip array 82 as a one-to-one erect image. However, since the CCD chips are arranged in a staggered manner as described above, and there is only one focusing rod lens array 21, in this embodiment,
The erect images formed on adjacent chips in the CCD chip array 82 become images spaced apart by four lines on the document surface 81. In order to solve this problem and obtain one line of continuous image signals, this embodiment uses a dedicated memory, as will be described later. Next, the light source 13 will be explained. In this embodiment, the light source 13 uses a fluorescent lamp. As mentioned above,
The function required of a contact type sensor as a color reading device is the ability to read colors in the same way as the human eye. FIG. 9 shows the Thomson-Wright basic curve. This curve shows the visibility characteristics of the human eye according to color, that is, the relationship between brightness perception for colored light and the wavelength of light. As is clear from the curves ₁ , ₂ , and ₃ , the human eye is not sensitive to light with wavelengths longer than 700 nm. On the other hand, as mentioned above, the spectral characteristics of the light receiving parts of the CCD chips 21 to 25 and the color filters have a finite sensitivity value even to light with a long wavelength of 700 nm or more. ~2
When white light is incident on the light receiving part of 5, it is 700nm.
Even light with longer wavelengths can be felt. Therefore, in this embodiment, a daylight-colored fluorescent lamp having almost no spectral characteristics in a long wavelength region of 700 nm or more is used. FIG. 10 shows the spectral characteristics of the above-mentioned fluorescent lamp. Fluorescent lamp 1 is a type of linear light source, but because the influence of the filament causes uneven brightness in the tube length direction, the tube length was changed to As shown in the figure, the length is set to be long (for example, 390 mm), and the illuminance non-uniformity is set within ±5% within the width direction of the A3 plate (297 mm). Furthermore, in order to increase the amount of light, fluorescent lamps are coated with reflective coatings and coated on the exterior walls.
It has a 30° aperture. Now, FIG. 12 is a block diagram of a color digital copying apparatus using the above-mentioned contact type color CCD sensor. The copying device 120 is a color image reading device 12
1 and a color image printing device 122. Reference numeral 14 denotes a document scanning unit shown in the first diagram, which moves and scans (sub-scans) in the direction of arrow A in order to read the image of the document 123 on the document table. During this moving scanning, the exposure lamp 13 in the document scanning unit 14 is turned on, and the light reflected from the document is focused by the converging rod lens array 12 into the contact type color scanner described above.
The light is focused on the CCD chip of the CCD sensor unit 11. The contact type color CCD sensor unit 11 includes
As mentioned above, 62.5μm (1/16mm) is considered as one pixel.
It has 1024 pixels (3072 bits) of effective signal pixels.
Five CCD chips are arranged in a staggered pattern.
Each pixel is divided into three parts from 15.5μm to 62.5μm, and each
Color filters of Cy, G, and Ye are pasted. Next, the electrical system related to the operation of the color CCD sensor unit 11 will be explained. The electrical system
An analog processing section consisting of an image sensor drive circuit that operates the CCD and an analog processing circuit that converts the output signal of the CCD into a form suitable for image information;
It consists of a digital processing circuit that converts the signal from the analog processing section into a signal suitable for the storage format. Further, the analog processing circuit and the digital processing circuit are collectively referred to as a sensor signal processing section. First, the image sensor drive circuit will be explained. However, in the following explanation, a driving circuit for the CCD chip 21 will be taken as an example. As shown in FIG. 14, this drive circuit includes two-phase clocks φ ₁ and φ ₂ for driving the CCD chip 21, a scanning synchronization signal SH, a reset signal RS, and
Handles the output signal OS of CCD21. Inverter 1 is connected to the input terminal of clock signal _φ1.
41 is connected to the output of the inverter 141, and a resistor 142 and a speed-up capacitor 143 are connected to the output of the inverter 141.
are connected in parallel, and further connected to an input terminal of a MOS clock driver 144. this
The output terminal of MOS clock driver 144 is CCD.
Connected to the _φ1 terminal of chip 21. Clock signal _φ2 is also similar to clock signal _φ1 .
In addition, the inverter 141 and the clock signals φ ₁ and φ ₂ are also connected to the scan synchronization terminal SH and the reset signal RS.
A resistor 142, a capacitor 143, and a MOS clock driver 144 are connected. Output signal OS terminal has npn transistor 145
and an emitter follower consisting of a collector resistor 146 and an emitter resistor 147 are connected. Also,
The power supply voltage +V of CCD chip 21 is capacitor 1
The signal is supplied to the OD terminal of the CCD chip 21 via 48 and 149. The two-phase clocks φ ₁ and φ ₂ are signals necessary to transfer the charges generated in each bit of the CCD chip 21 in a bit-serial manner. The scan synchronization signal SH is a signal that distinguishes one scan in the charge transfer of the CCD chip 21, and the reset signal RS is a signal that erases the bit (charge) after the charge of each pixel has been transferred. Also, the signal
OS is output in synchronization with two-phase clocks φ ₁ and φ ₂
These are output signals from the CCD chip 21, and as shown in FIG. 4 described above, each chip outputs an effective signal (3072 bits), a dummy signal, a blank feed signal, and a reference black level signal from the light shield pixel. These signals have precisely defined bit positions,
The reference black level signal is a dark signal of the light receiving section, and is used to obtain a true output according to color. Next, the sensor signal processing section is shown in FIG. This sensor signal processing section is provided independently for each CCD chip 21-25. Here as a representative
The circuit for the CCD 21 will now be explained. As shown in FIG. 13, the output signal OS from the CCD chip 21 is sent to the buffer circuit 131 for each color of cyan (Cy), green (G), yellow (Ye), and black (BK). It is input to a multiplexer 132 for separation. Then, in the dark level removing section 133, the difference between the output signals of each color (Cy, G, Ye) from the multiplexers 132a, b, c and the reference black level signal (BK) from the multiplexer 132d is taken, and the , and then the next stage color conversion section 1
The voltage is amplified to be input to 34. In the color conversion section 134, the dark level removal section 133
Outputs the primary color signals of blue (B), green (G), and red (R) from the outputs of each color (Cy, G, Ye) from the input signal level of the A/D converter 135. Amplify and output the signal (R, G, B). The AD converter 135 converts the signal from the color converter 134 into a digital signal, and converts the A/D
The signal from the conversion section 135 is stored in the memory section 139. The multiplexer 132 includes four sample and hold (S/H) circuits 132a to 132a to 132a, which separate the output signals from the buffer circuit section 131 for each color, as described above.
Consisting of 32d. In addition, the dark level removal section 13
3 consists of three differential amplifiers 133a to 133c. The color converter 134 includes three differential amplifiers 134a to 134c for converting the signals Cy, G, and Ye into signals B, G, and R using the G signal as a reference. A/D
The conversion unit 135 includes three A/D converters 135a to 135a that convert signals amplified for each color into digital signals.
135c, and three latch circuits 136a to 136c for latching its digital output. In this embodiment, a contact type color CCD sensor unit 1 is mounted on the signal processing board 16 of the original scanning unit 14.
1 as well as an analog processing circuit system including A/D converters 135a to 135c, and
From the latch circuits 136a to 136c to the memory section 13
9 and a main body board 124 equipped with a digital signal processing section, which will be described later, etc., by a flexible electric wire 17. In this way, a digital signal is transmitted from the scanning unit 14 to the main body board 124, which is less susceptible to the effects of noise, etc., thereby making it possible to reproduce a good image. The memory section 139 consists of storage areas 139a to 139c provided for each of R, G, and B. The above is the main configuration of the sensor signal processing unit provided corresponding to the CCD chip 21, but in addition to these elements, several control elements are provided. These will be explained together with the circuit operation using the detailed drawings below. FIG. 15a shows a detailed circuit configuration of the signal processing board 16 on the original scanning unit 14. Figure 15a
17-1 is a moving part of an image sensor, an illumination lamp, an analog processing circuit of the sensor signal processing section, an image sensor drive circuit,
It is a flexible power source that supplies multiple clock pulses and power to drive the image sensor (CCD) and sensor signal processing section to the document scanning unit 14 including the optical lens system. On the other hand, 1
7-2 is a flexible electric wire for sending the digital color signal from the sensor signal processing section to the main body. 153 is a clock buffer receiver that receives a plurality of clock pulses sent through the flexible wire 17-1, and 154 is an image sensor clock driver that boosts the signal from the clock buffer receiver to a voltage at which the image sensor can operate. , 21 is an image sensor (CCD) for reading the original image on the original platen glass, and 156 is for capturing and holding time-series color pixel signals of BK, C, G, and Y in the image signal VIDEO output by the image sensor 21. Sample pulse SMPC, SMPG, sample hold circuit corresponding to each color
A sample hold driver drives according to SMPY and SMPK; 157 is a buffer transistor that receives BK, C, G, and Y time-series color pixel signals output from the image sensor 21; 158 is a BK output from the buffer transistor 157; C,
A demultiplexer for transmitting G, Y time-series color pixel signals to sample and hold circuits for each color.
It is a buffer transistor. 1509 to 1512 operate as switches to capture and hold the C, G, Y, and BK time-series color pixel signals output by the image sensor 21 by separating them into four totally parallel signals of cyan, green, yellow, and black levels, respectively. C transistor switch, G transistor switch, Y transistor switch, BK transistor switch, 1514
~1517 is the transistor switch 1509
~1512 output voltages respectively as cyan signal voltages
V _C ′, green signal voltage V _G ′, yellow signal voltage
C hold capacitor, G hold capacitor that holds V _Y ' and black level signal voltage V _BK ,
These are Y hold capacitor and BK hold capacitor. 1518 to 1520 are the above V' _C , V' _G ,
These are a C high input differential FET, a G high input differential FET, and a Y high input differential FET that remove and amplify the V _BK component contained in _V'Y . 1521~
1523 is the above C, G, Y high input differential FET1
A C level shifter transistor and a G level shift transistor that remove the DC components contained in the color pixel signals, that is, αV _C , βV _G , and γV _Y from which the V _BK component is removed and amplified by α, β, and γ times at 518 to 1520. , Y level shifter transistor, 1
524 to 1526 are C emitter follower transistors that convert the outputs of the level shift transistors 1521 to 1523 into low output resistances, respectively;
These are a G emitter follower transistor and a Y emitter follower transistor. 1527 is C emitter follower transistor 1
524 and G emitter follower transistor 15
25, extracts the difference component between both signals, and amplifies it by 1/H, that is, I/H・V _B
B differential amplifier buffer that creates a color difference signal,
1528 is G emitter follower transistor 15
G differential amplifier buffer which receives the output from 25 and amplifies it by 1/J, that is, 1/J・V _G ; 15
29 is a G emitter follower transistor 1525
The difference component of both signals is extracted by receiving the output from the Y-emitter follower transistor 1526 and the output from the Y emitter follower transistor 1526, and is amplified by 1/I, that is, by 1/I.
This is an R differential amplifier buffer that produces a color difference signal called V _R. 1530 is B differential amplifier 1527
The analog pixel signal output by A/D clock B
A BA/D converter 1531 converts the signal into a digital pixel signal, and 1531 is a G differential amplifier buffer 1528.
The analog pixel signal output by the A/D clock G
A GA/D converter 1532 converts the signal into a digital pixel signal according to the R differential amplifier buffer 1529.
The analog pixel signal output by the A/D clock R
This is an RA/D converter that converts the pixel signal into a digital pixel signal. 1533 receives blue, green, and red digital pixel signals respectively output from A/D converters 1530 to 1532, and connects the flexible electric wires 17-
2 is a line driver for sending each color digital pixel signal to the main body, and 1534 is a line driver for each A/
This is a voltage reference that draws a reference voltage for digital conversion into the D converters 1530 to 1532. The operation of the image sensor drive circuit and sensor signal processing section will be explained below with reference to FIGS. 15a and 15b mentioned above. As mentioned above, the sensor unit 11 of this embodiment is composed of five CCD chips 21 to 25, and the circuits described below are respectively provided for each of these five CCD chips and operate in parallel. Therefore, the time required for image processing for one line is shortened, and each element such as an A/D converter does not need to operate at such high speed. In order to operate the image sensor 21, the 15th
SH pulse shown in figure b, φ ₁ pulse,
_φ2 pulse and RS pulse are required. The role of these pulses is as described above, but due to the nature of the image sensor, these driving pulses require a higher pulse voltage than the pulse voltage on the main body side. Therefore, each sensor driving pulse generated by the CCD pulse generator 137 shown in FIG. , image sensor clock driver 15
4, after forming the high pulse voltage described above,
It is applied to image sensors 21-25. The image sensor receives this pulse voltage and generates color separation signals of cyan, green, and yellow according to the input light.
V' _C , V' _G , V' _Y and the aforementioned light shield pixel signal V _BK are output in time series as shown in FIG. 15b. The image sensor driven by the image sensor drive circuit described above has V _BK , V′ _C ,
Pixel signal voltages are output in the order of V′ _G , V′ _Y , V′ _C , V′ _G , V′ _Y , etc., but until these analog pixel signals are sent to the digital data processing section of the main body, Some analog signal processing and digitization of analog quantities must be performed. One of these analog processes is color conversion. This converts the cyan, green, and yellow color pixel signals output by the sensor into blue, green, and red by performing mutual calculations on each pixel. This is because the sensor characteristics are that higher signal levels (higher contrast signals) can be obtained by outputting cyan, green, and yellow signals than by directly outputting blue, green, and red signals; on the other hand, digital color images Due to mutual discrepancies in the characteristics of the processing unit, such as the circuit being simpler when receiving blue, green, and red signals, the cyan, green, and yellow signals output by the sensor are purposely converted to blue, green, and red. That's what I do. Another analog process is to remove floating voltage components uniformly included in the cyan, green, and yellow color separation signals output by the image sensor. This floating voltage component is hereinafter referred to as V _BK , and this is due to the dark voltage fluctuation of the photodiode inside the image sensor and the charge fluctuation of the CCD channel, etc., and the output voltage of the image sensor is V _C ′, V _G ′, V It is thought that they exist at the same level in _Y ′. Therefore, before performing the above color conversion, this floating voltage component V _BK is removed from each color component to extract pure color signal components. Another analog process is to match the color converted blue, green and red analog quantity color signals to the input levels of the A/D converter to convert them to digital quantities. Furthermore, other analog processing is performed to perform the above-mentioned color conversion, that is, between color pixel signals sent in time series in the _{order of} cyan → green → yellow,
Alternatively, it is a process to parallelize the time series in order to perform a subtraction process of V _Y −V _G. The operation related to color conversion processing of the sensor signal processing section will be explained with reference to FIGS. 15a and 15b. First, considering that the time-series color signal output from the image sensor includes the aforementioned floating voltage component V _BK , this time-series color signal is expressed as V _C ′=(V _C +V _BK ), V _G ′ =(V _G +
V _BK ), V _Y ′=(V _Y +V _BK ). The image sensor time-series color signal and floating voltage components, V _C ', V _G ', V _Y ', and V _BK applied to the base of buffer transistor 157 are further input to demultiplexer buffer transistor 158 . Transistor switches 1509 to 1512 for each color are connected to the emitter of this transistor 158 in a reverse bias state. When the sample pulse from the sample and hold drive transistor 156 does not come, the resistance between the emitter and the collector of each transistor switch becomes high, and the sample and hold capacitors 1514 to 1517 connected to the collector have high input and differential FETs 15.
18-1520 are disconnected from the emitter of the demultiplexer buffer transistor 158. This is a signal hold operation. On the other hand, as shown in FIG. 15b, the wire is sent from the main body by a flexible electric wire 17-1. Black, cyan, green, yellow sample pulses SMPK, SMPC, SMPG,
When SMPY is applied _to the sample-and _- hold drive _transistor group 156 at the appropriate timing shown, the transistors ₁₅₈ The emitter voltage of is 1517,1
514, 1515, and 1516 move to the sample hold capacitor in this order. Here, the time-series color signal voltages and floating component voltages are divided into parallel voltages V _BK , V _C ′, V _G ′, and V _Y ′, that is, demultiplexed. As each sample pulse passes, each transistor switch immediately returns to its original high resistance state, and the voltages V _BK , V _C ′, V _G ′, and V _Y ′ are applied to the respective sample and hold capacitors 1514.
~1517 remains. Sample hold capacitor 1514-151
One differential input is connected to each of 6, and each other input is connected to a hold capacitor 151 for floating voltage component.
Three high input differential FETs connected to 7
The drain output voltage of the 1520 generates the following output voltage depending on the characteristics of the differential amplifier.・ Differential FET output 1518 α(V _C ′−V _DK = α(V _C +V _DK −V _DK )=αV _C …(1) Where α is the voltage gain of this FET circuit ・ Differential FET output 1519 β(V _G ′−V _DK = β(V _G +V _DK −V _DK )=βV _G …(2) However, β is the voltage gain of this FET circuit and the differential FET output 1520 γ(V _Y ′−V _DK = γ(V _Y + V _DK − V _DK ) = γV _Y …(3) where γ is the voltage gain of this FET circuit As shown in the above equations (1), (2), and (3), each FET output has a floating component voltage V Color pixel signals αV _C , βV _G , γV _Y with _DK removed and multiplied by a constant gain appear (Figure 15b, ). The gain coefficients α, β, and γ shown here are necessary for color conversion. In other words, in order to create signals V _B and V _R corresponding to blue and red from cyan, green, and yellow signals, the following calculation is required: HV _B = α.V _C −βV _G where H is a constant…(4) JV _G =βV _G where J is a constant…(5) IV _R =γ.V _Y −βV _G where I is a constant…(6) Each high input differential FET1518 to 1520 The output of level shifter transistors 1521 to 1523
After the DC offset voltage superimposed on each color pixel signal αV _C , βV _G , γV _Y is removed in parallel, the emitter follower transistor 15
24-1526. Color pixel signals of αV _C , βV _G , γV _Y driven by low output resistance by emitter follower transistors 1524 to 1526 are sent to color difference detection differential amplifier buffers 1527 to 152.
given to 9. The differential amplifier buffer 1527 calculates each color signal voltage of α, V _C , β, and V _G given to its input by performing the calculation operation shown by equation (4) according to the characteristics of the differential amplifier, and by its amplification capacity. By removing the H term in equation (4), a pure V _B color conversion output is created (Figure 15b). Also, the differential amplifier buffer 1529 similarly receives γ and
It receives each color signal voltage of V _Y and βV _G and performs the arithmetic operation shown in equation (6), and generates a color conversion output of pure _VR with the I term removed by an amplification effect (15th
Figure b). Furthermore, the differential amplifier buffer 1528 operates as a normal amplifier buffer, amplifies the color signal βV _G sent from the previous stage, and cancels the J term in equation (5), thereby increasing the chrominance signal by 1 for each of the above-mentioned V _B and V _R . Outputs a _VG color signal that is one-to-one. The above-described operations of the differential amplifier buffers 1527 to 1529 do not need to be performed at the same timing, but are performed using each color signal while maintaining the phase difference of the previous stage. The color pixel signals converted into V _B , V _G , and _VR in this way are used for A/D conversion to be output from the A/D pulse generator on the main body side, which is applied to each A/D converter 1530 to 1532. Clock A/D CLKB, G,
After being analog-to-digital converted according to R, the signal is sent to the digital color processing section of the main body through a flexible electric wire 17-2 driven by a line buffer 1533. Here, the A/D converters 1530 to 1532 perform an A/D conversion operation based on one function that takes density correction (γ correction) into consideration for the image signal. That is, it is a function transformation expressed by the following formula: D=-logR D: optical reflection density R: reflectance. For this conversion operation, the A/D converters 1530 to 1532 are configured to externally supply reference voltages necessary for quantization, but the voltages applied between the plurality of reference voltage setting terminals are equalized. Undifferentiated, nonlinear voltage 15
34 to obtain a polygonal function approximation. The analog color pixel signal _VB , which is the reflectance data that has undergone logarithmic A/D conversion and has its polarity inverted in this way,
When V _G and _VR exit the A/D converters 1530 to 1532, they become density data in the form of 8-bit digital quantities D _R , D _G , and D _B and are sent to the main body. In this way, the A/D converters 1530 to 1532
A/D for input analog color signal
At the same time as the conversion, γ correction of the image signal is performed. FIG. 24 shows the above-mentioned A/D converters 1530 to 15.
32 input/output characteristics. As shown in the figure, there are three points of contact, and by connecting these points, the exponential function is approximated by a polygonal line. Note that the input/output characteristics are set to be suitable for the characteristics of the sensor including the filter, the printer, etc. As mentioned above, the density data D B , D G , corresponding to _B , G, and _R converted into 8-bit 256-gradation digital signals by the A/D converters 1530 to 1532,
D _R is provided on the main body side, and A/D pulse generator 1
Latch circuits 136a to 136c which are latched by the latch clock (CLK) output from 38.
The phase is aligned by this. Here, the number of digital signals is evaluated. In this embodiment, the signals from the continuous CCD chips 21 are separated into three colors one bit at a time by the multiplexer 132 as described above. Therefore, the number of signals for each color taken into the latch circuit 136 is 1/3 of the number of signals from the CCD chip 21, as shown in FIG. For example, the effective reading area in the CCD chip 21 is
Since it is 3072 bits, the output signal corresponding to one color of R, G, and B is 1/3 of that, 1024 bits. The above signals are sent to the memory section 139 as a clock.
Stored according to CLK1. The memory section 139 corresponds to each of the CCD chips 21 to 25, and storage areas are set according to each color (R, G, B). For the CCD chip 21, storage areas 139a, 139b and 139c are set for B, G and R, respectively. Further, as will be described later, the capacity of this storage area varies depending on the arrangement of the CCD chips 21 to 25. In other words, as mentioned above, in this embodiment, one convergent rod lens array 12 is used to connect the CCD chip 21 with a spatial distance of 4 lines.
Since the image is focused on ~25, the first column
Images read by the CCD chips 21, 23, 25 and the second row CCD chips 22, 24 at the same time are always viewed at positions shifted by four lines. Therefore, in this case, the image shift of four lines is corrected, and continuous signals of the same line are formed by the memory section. Here, the memory sections 139a to 139c are static RAMs (Random Access Memories), and the memory capacity for one line is 1024.times.8 bits since each pixel has an 8-bit signal as described above. Therefore, the address is 0 to 1023 in 8-bit units.
Even the street address is set. The writing and reading of information into and from the memories 139a to 139c will be explained below, but particular attention should be paid to the arrangement of the CCD chips 21 to 25 and the removal of signal overlap in the main scanning direction by the focusing rod lens array 12. , is a connection between signals in the sub-scanning direction. FIG. 16 shows a memory control section 140 that controls the memory section 139 described above, and a memory section 139 that controls the memory section 139.
A memory 139a corresponding to blue density data is shown. The memory control unit 140 includes a write address counter 161, a read address counter 162,
Memory block selector 163, CS control unit 16
4,165,166, magnification selector 167, 17
It consists of 1R/control sections 168, 169, and 170. The memory 139a includes a memory block 172 corresponding to the CCD 21, a memory block 173 corresponding to the CCD chip 22, a memory block 174 corresponding to the CCD chip 23, a memory block 175 corresponding to the CCD chip 24, and a memory block 176 corresponding to the CCD chip 25. Become. Furthermore, each of the memory blocks 172 to 176 is composed of a plurality of small memory blocks, and each of the small memory blocks has one memory block.
Stores color information (8 x 1024 bits) for each line. Next, each memory block 172 of the memory 139a
The capacity of ~176 will be explained. As shown in Fig. 3 and above, CCD chips 21, 23, 25 and CCD
Chips 22 and 24 have a spatial distance of four lines. Considering that each CCD chip normally has a 2-line small memory block as a switching buffer, each line output from the small memory block
The data obtained by connecting the images of the CCD chips in the main scanning direction becomes image data that is shifted by four lines in the areas of the CCD chips 21, 23, 25 and the CCD chips 22, 24. Therefore, in this embodiment, the CCD chip 22, which reads the image in advance in sub-scanning,
24 image data is stored line by line in a small memory block, and the following CCD chip 21,
23 and 25 are the preceding CCD chips 22 and 24
When the image data of the same line is read, the image data stored in the CCD chips 22 and 24 is read out together with the CCD chips 21, 23, and 25 in synchronization. By doing this,
The same line of data is always output from each CCD chip 21-25. Let us now consider the number of small memory blocks that constitute each memory block. For example, adjacent CCD chip 21 and CCD chip 2
Considering the relationship 2, when reading at the same magnification, the
By the time the CCD chip 21 scans the same line as the position currently being scanned by the CCD chip 22, 4
There is a time difference of one line, and in the end, the leading CCD
The difference in the number of small memory blocks between the chip 22 and the following CCD chip 21 is 4 lines. Since the trailing CCD 21 requires two lines for reading and writing, the leading CCD 22 requires at least a total of six small memory blocks. Next, let us consider the case where variable-magnification reading is performed by varying the sub-scanning speed. In addition, the magnification in the main scanning direction is
This is performed electrically by thinning out or padding the image signal. In this case as well, the timing of writing and reading is as described above.
24 and the following CCD chips 21, 23, and 25 scan the same line, so if there is a spatial distance of 4 lines, the magnification ratio will be determined to be a multiple of 1/4. Considering the above, each CCD
Calculating the number of memory blocks required at each magnification of
It will look like this: CCD21, 23, 25: CCD22, 24 x 0.5 times: 2 4 x 0.75 times: 2 5 x 1 times: 2 6 x 1.25 times: 2 7 x 1.5 times: 2 8 To summarize the above, between the CCD chips If the distance is N lines, the number of leading CCD chips is a, and the number of trailing CCD chips is b, then the magnification unit is B,
The following relationship holds true among the maximum magnification L, the required number of memory lines M of the preceding CCD chip, and the total number of lines A of the entire sensor. B=1/N M=L・N+1 A=a(L・N+2)+2b Therefore, in this example, the magnification of magnification is ×0.75, ×1,
×1.25, so the memory blocks 172, 174, and 176 have 2 lines, and the memory blocks 173 and 175 have 6 lines, and in total, each color has 18 lines of small memory blocks. have Next, FIG. 18 shows a configuration diagram of a small memory block. Each small memory block is a static
RAM 182 (8 x 1024 bits) and static RAM 182 write address (W-
ADDRESS) and read address (R-
ADDRESS) data selector 181 for switching
A bus driver (BUSS driver) 183 that controls the input and output of image data signals from the CCD chip;
184, and OR circuit 185, inverter 18
Consists of 6. Here, regarding the above control, FIGS.
The circuit diagram and timing chart shown in Figure 17,
This will be explained with reference to FIGS. 19, 20, and 21.
In addition, FIG. 17 is a timing chart of the sensor signal processing section mentioned above, and FIG. 19 is a timing chart of the chip select signal CS and read/write signal R/ corresponding to each small memory block when reading at a variable magnification of ×0.75. FIG. 20 is a timing chart of the chip select signal CS and read/write signal R/ corresponding to each memory block when reading at a variable magnification of ×1. Chip select signal CS and read/write signal R/ corresponding to small memory block
This is a timing chart for W. First, we will use the same magnification (×1
We will explain the control of image reading when the CCD chip 22 is
With chip 21, other CCD chips 23 and 2
The operations of Nos. 4 and 25 are representative. In FIG. 16, a write address counter 161 controls the address for writing data into the static RAM of each memory block.
This is done by counting CLK1, and the read address counter 162 controls the read address of the static RAM of each memory block.
This is done by counting CLK2. At this time, the number of data written to each small memory block is 1024 pixels as described above, and when reading this, data equivalent to the length of the short side of an A3 size paper (297 x 16 pixels) is written from five small memory blocks. = 4752 pixels) must be read out at once. Therefore, the clock CLK applied to the read address counter 162
2 is 4.5 times the clock CLK1 applied to the write address counter 161, and requires a frequency 1.5 times the frequency of the clocks φ ₁ and φ ₂ that drive each CCD chip. Further, the read counter 162 is a 13-bit counter, and the lower 10 bits are outputted as a read address, and the upper 3 bits are outputted to the memory block selector 163. The memory block selector 163 decodes the upper 3 bits of the read address counter mentioned above and determines the data width of each memory block 172-176. In other words, the amount of data before each memory block is connected to one line is 5120.
The amount of data required to output for (1024×5) is
4752, so we need to remove the difference of 368 bits. Therefore, read address counter 16
By specifying the initial value of the output address in step 2, the data before and after each CCD chip is deleted, making the total data width 4752. As mentioned above, 164, 165, and 166 are the CS control units, which control the HS and NC2 synchronized with the line synchronization signals HS and NC of the printer from the digital data processing unit.
Line counter 1 (1641) that counts line counter 1 (1641), line counter 2 (1642) that operates by the LD signal from line counter 1 (1641), and line counter 1
(1641), line counter 2 (1642), and a CS that combines the signals of the memory block selector 163.
It is composed of a matrix circuit 1643. The CS control units 164, 165, and 166 are provided corresponding to the number of stages of the magnification ratio, and in this embodiment,
There are three sets corresponding to ×0.75 and ×1.25, respectively. 168, 169, and 170 are R/control units as described above, and CS control units 164 and 170 correspond to each magnification.
The outputs of line counters 1 (1641) and 2 (1642) of 165 and 166 are combined to create an R/ signal for each memory block. In addition, R/control unit 1
68, 169, 170 are also CS control units 164 to 16
Similarly to 6, the number of magnification ratio stages is provided. The above-mentioned CS control units 164 to 166 and R/
The CS, R/signals corresponding to each magnification generated by the control units 168 to 170 are sent to the magnification selector 16.
7,171, the data is selected in accordance with the magnification and input to the static RAM of each memory block. Now, Figure 20 shows the case when reading an image x1x.
This is a timing chart of CS, R/signals.
The numbers 11 and 12 attached to CS and R/ are assigned to small memory blocks 172a and 172b, 21 to 27 are assigned to small memory blocks 173a to 173g, 31 and 32 are assigned to small memory blocks 174a and 174b, and 41 to 47 are assigned to small memory blocks 173a and 173g. Signals 51 and 52 correspond to blocks 175a-g and small memory blocks 176a and 176b, respectively.
When the preceding CCD chip 22 performs the first scan, the small memory block 173a of the memory block 173 corresponding to the CCD chip 22
Set CS21 to "0" and R/21 to "0".
In this state, A of the data selector 181 in FIG.
That is, the write address (W-ADRESS) from the write address counter 161 is selected, the bus driver 183 is activated, and data from the CCD chip is input to the static RAM 182 via the bus driver 183. At the same time, the OR circuit 185 generates a write pulse W-CLK when R/ is "0" (Figures 16 and 18).
is input to the terminal of the static RAM 182. By doing as described above, the data of the first line scan of the CCD chip 22 is stored in the static RAM 182 of the small memory block 173a of the memory block 173. Furthermore, at the same time
The scanning data of the first line of the CCD chip 24 is stored in the small memory block 17 of the memory block 175.
It is accumulated in 5a. Similarly, in the second line of scanning, CS22 and R/22 are selected, and the small memory block 17 of the memory block 173 corresponding to the CCD chip 22 is selected.
The data of the second line is stored in the static RAM 3b. In this way, images of 3rd and 4th lines are stored, and when the 5th line is scanned, the following CCD chip 21 and the CCD chip 22
Scan the same line that was scanned the second time,
The data obtained by this scanning is transferred to the CCD chip 21.
The data is stored in the small memory block 172a of the memory block 172 corresponding to the data. At this point, the data on the same line, that is, the data in the small memory block 172a and the data in the small memory block 173a are now complete. When scanning the next 6th line, first, CS11
is “0”, R/11 is “1”, S of the data selector 181 is “1”, B is selected, and the read address (R
-ADRESS) is input to the static RAM 182 of the small memory block 172a of the memory block 172 corresponding to the CCD chip 21, and
Since WE is "1", WE is "0", and the bus driver 184 is set to "0" by the inverter 186 and selected, the static state is synchronized with the read address.
RAM data is output via bus driver 184. Next, when CS11 becomes “1”, CS21
becomes “0”, and the data in the static RAM of small memory block 173a is transferred to small memory block 1.
The data of 73a is output continuously. Below, according to the timing chart in Figure 20,
CS and R/ of each memory block are selected in sequence,
It inputs and outputs data and outputs data connected to one line. This is done simultaneously for the three colors R, G, and B, as shown in FIG. (A/D output B, G, R) Figure 19 is a timing chart of the CS and R/ signals when reading an image at ×0.75 times, and Figure 21 is at ×1.25 times. Control is performed according to a timing chart. As described above, 8-bit color separation image data signals D _R , _DG ,
D _B is read from the memory 139 and subjected to the processing shown in FIG. 22 and thereafter. That is, the color correction circuit 221 performs the processing shown in (1) below, which is usually called masking, to form yellow Y, magenta M, and cyan C signals, and also generates a black plate and undercolor removal circuit 2.
In step 22, the process shown in (2) below is performed. (1) Masking...input, pixel data, _DR , _DG ,
Perform the matrix operation shown by the following formula on D _B ,
Absorbs unnecessary color components of printing toner, Y,
Forms M and C signals. Y M C=a ₁ b ₁ c ₁ a ₂ b ₂ c ₂ a ₃ b ₃ c ₃ D _R D _{G D} BHere, the coefficients a _i , b _i , c _i (i=1 to 3) are appropriate values. This is the masking coefficient to be set. (2) Darkening plate generation/undercolor removal... Minimum value of Y, M, C signals, that is, when MIN (Y, M, C) = k, Y' = Y - αK, M' = M - βk , C'=C-γk, each color signal Y', M', which indicates the amount of toner to be printed,
Determine C′ and use BK=δk as a black printing plate. (Set α, β, γ, δ to appropriate values) Each image data Y′, M′,
C' and BK (black) become the basic data of the toner image that is finally printed by the printer.As will be explained later, the color printer in this system uses toner images of Ye (yellow) and M (magenta).
toner image, Cy (cyan) toner image, and
Instead of printing out BK (black) toner images at the same time, each image is transferred to transfer paper one after another, and the four colors are layered one after another to obtain the final color print image. Therefore, each color data Y′, M′, obtained here
It is necessary to select C', BK according to the operation of the color printer, and the selector 223 selects Y', M',
Select one color from C′ and BK (black). Therefore, in this system, four original exposure operations and four toner image forming processes are required to read and print out one color image. Now, the color separation image selected in accordance with the operation of the color printer 122 is transferred to the image area separation circuit 22.
4, it is separated into a character area such as characters, symbols, lines, etc. and a halftone image area such as a photograph, and the halftone image is subjected to multi-value processing (usually referred to as dither processing) by a multi-value processing circuit 225. The character area is binarized using a single threshold value in the binarization processing circuit 226, and the image data transferred at 8 bits and 256 gradations is converted into dots of "1" and "0" for each pixel. Convert to image. FIG. 12 122 is a cross-sectional view of the printer,
This color printer is an electrophotographic laser beam color printer and includes a photosensitive drum 125. Further, FIG. 23 shows a detailed diagram of the latent image forming section. The image creation process will be explained. Color reader 1 mentioned above
The color separated image read in step 21 is developed into a dot image through each block shown in FIG. 22, and the dot data corresponding to the color image finally modulates the semiconductor laser 231 shown in FIG. 23. The laser beam modulated in accordance with the image is scanned at high speed in the width direction from A to B in FIG.
1, the surface of the photosensitive drum 125, which is uniformly charged, is exposed to dots corresponding to an image. One horizontal scan of the laser beam corresponds to one horizontal scan of the image, and in this embodiment, the width is 1/16 mm. On the other hand, since the photosensitive drum 125 is rotating at a constant speed in the direction of the arrow, the above-mentioned laser beam scans in the main scanning direction, and the constant speed rotation of the photosensitive drum 125 in the sub-scanning direction causes
A planar image is exposed on the photosensitive drum 125 from time to time. An electrostatic latent image is formed on the photosensitive drum 125 by such laser exposure, and by developing this latent image with the developing sleeve 1218, a toner image corresponding to the input image data is formed on the photosensitive drum 125. For example, the first
Considering the second original exposure scan, first,
A dot image of the yellow component of the original is exposed onto the photosensitive drum 125 by a laser 131 and developed by a yellow developer 1221 . Next, this yellow image is transferred onto the sheet of paper 232 wound around the transfer drum 1210 by a transfer charger 1221 provided at the contact point between the photosensitive drum 125 and the transfer drum 1210. The same process is done with M (magenta), Cy (cyan), and BK (black).
By repeatedly overlapping the toner on the paper sheet 232, a color image is formed using four color toners. In this way, the paper sheet 2 after the transfer of the four-color image is completed.
32 in FIG. 12, it is peeled off from the transfer drum 1210 by a peeling claw 1222 and transferred to the conveyor belt 1223.
As a result, the color toner image is guided to an image fixing section 1224, and the color toner image is melted and fixed onto the paper sheet by heat pressure rollers 1225 and 1226, thereby obtaining a print image. 12, 1229 and 1230 are cassettes for storing paper sheets, 1231 and 1232 are paper feed rollers,
Reference numerals 1233 to 1235 are timing rollers that take the timing of paper feeding and conveyance, and the paper sheet fed and conveyed via these is guided to a paper guide 1236, and as shown in FIG. is carried by the gripper 233 and wound around the transfer drum 1210, and the image forming process begins. On the other hand, 1240 in FIG. 12 is a developing unit for each color for developing the electrostatic latent image formed on the surface of the photosensitive drum 125 by the above-mentioned laser exposure.
Rotate in 90 degree increments. 1218Y, 1218M, 1
218C and 1218BK are development sleeves 12 that directly develop each color in contact with the photosensitive drum 125;
20Y, 1220M, 1220C, 1220BK
is a toner pot that holds spare toner, 12
Reference numeral 19 denotes a skillium for transporting the developer. In such a configuration, for example, M (magenta)
When forming a toner image, the developer unit rotates around P in FIG.
0M is placed. As a result, the photosensitive drum 12
The electrostatic latent image formed on 5 is developed with magenta toner. Incidentally, development of Cy (cyan) and BK (black) is operated in the same manner. As described above, according to the present invention, a plurality of line sensors each generating color component signals of a plurality of colors are provided, the plurality of line sensors share one line on a document, and adjacent line sensors Since the original is read using a reading means that reads different lines on the original, it is possible to separate and read one line of a color original with high resolution. By delaying the output from the line sensor that reads the document in advance with respect to the output from the line sensor that reads the document in the subsequent order, a continuous color component signal of multiple colors for one line is generated. The reading means is equipped with a plurality of forming means for forming each color component for each color component, and a setting means for setting the amount of delay for the output from the line sensor that pre-reads the document in the plurality of forming means in accordance with the reading magnification. In a configuration in which the document is read at an arbitrary magnification by relatively moving the document and the document in a direction perpendicular to the scanning direction of a plurality of line sensors at a speed corresponding to the reading magnification,
It becomes possible to satisfactorily obtain continuous color component signals of multiple colors for each color component for one line in which deviations in the reading positions of multiple line sensors are removed, and therefore color originals can be read with high resolution and Good reading is possible at any reading magnification.

[Brief explanation of the drawing]

Figures 1a and b are diagrams showing an example of the configuration of a reading section, Figure 2 is a diagram showing an example of the configuration of a color CCD sensor unit, Figure 3 is an explanatory diagram of the arrangement of adjacent CCD chips, and Figure 4 is a diagram showing an example of the configuration of a color CCD sensor unit. A diagram showing each area of the CCD chip,
Figure 5 is a diagram showing the color filters provided on the CCD chip, Figure 6 is a diagram showing the spectral characteristics of each color filter, Figure 7 is a diagram showing the spectral characteristics of the light receiving section, and Figure 8 is a diagram showing a part of the reading section. The diagram showing the configuration, Figure 9, is
Diagram showing the basic Thomson-Wright curve, No. 10
Figure 11 is a diagram showing the spectral characteristics of a fluorescent lamp, Figure 11 is a diagram showing the relative brightness of a fluorescent lamp, Figure 12 is a diagram showing an example of the configuration of a color digital copying machine, and Figure 13 is a diagram showing the sensor signal processing section. 14 is a block diagram of the image sensor drive circuit, FIG. 15a is a diagram showing the circuit configuration of the signal processing board, and FIG. 15b is a timing chart showing the operation of each part of the signal processing circuit of FIG. 15a. 16 is a block diagram showing the structure of the memory section and memory control section, FIG. 17 is a timing chart showing the operation of each part of the signal processing section, FIG. 18 is a block diagram of the small memory block, FIG. 20th
21 and 21 are timing chart diagrams showing memory read and write operations, FIG. 22 is a block diagram showing the configuration of a digital color signal processing circuit, and FIG.
FIG. 3 is a diagram showing the configuration of a latent image forming section in the printer, and FIG. 24 is a diagram showing A/D conversion characteristics.
In the figure, 11 is a sensor unit, 12 is a focusing rod lens array, 13 is a light source, 16 is a signal processing board, 17 is a flexible electric wire, 21 to 25
is a CCD chip, 132 is a multiplexer, 13
3 is a dark level removal section, 134 is a color conversion section, 1
35 is an A/D conversion section, and 139 is a memory section.

Claims (1)

[Claims] 1. A plurality of line sensors each generating color component signals of a plurality of colors are provided, the plurality of line sensors share one line on a document, and adjacent line sensors share a line on a different line on the document. a reading means for reading the reading means; a moving means for relatively moving the reading means and the document in a direction perpendicular to the scanning direction of the plurality of line sensors at a speed corresponding to a reading magnification; and each of the plurality of line sensors. a plurality of separating means, provided corresponding to each of the plurality of color component signals, for separating color component signals of a plurality of colors generated by each of the plurality of line sensors for each color component; and a plurality of separation means provided corresponding to each of the plurality of color component signals. , by delaying the output from the line sensor that reads the document in advance with respect to the output from the line sensor that reads the document in the rear, one line of continuous color component signals of multiple colors is generated for each color component. A color image comprising: a plurality of forming means for forming a color image; and a setting means for setting a delay amount for an output from a line sensor that pre-reads the document in the plurality of forming means in accordance with the reading magnification. reading device.