JPH086326A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device capable of offering uniform color reproducibility. CONSTITUTION:The image density of a document D transmitted to a photoreceptor drum is detected by an automatic exposure sensor 38, and the image density of a red image contained in the document D is detected by a red image detecting sensor 40 respectively in a copying device 2. The output indicating voltage Vcnt to be fed to a lamp regulator feeding voltage to light a lighting lamp is obtained by a CPU. In the region corresponding to the red image, the output indicating voltage Vcnt shows low voltage similar to the lamp voltage offered in the white (no image) region. The print of a seal in red seal ink is prevented from being blurred, for example.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus which forms an image on an image bearing member by an electrostatic photography process, develops the image with toner and outputs it on a sheet.

[0002]

2. Description of the Related Art In an image forming apparatus, for example, an electrostatic copying apparatus, a latent image is formed on a photosensitive drum which is charged in advance with a predetermined polarity by reflected light from the original obtained by illuminating the image of the original. It is formed. The latent image formed on the photoconductor drum is developed by supplying toner from the developing device, and is transferred as a copy image onto a transfer sheet attracted to the photoconductor drum by electrostatic force.

The copy image, that is, the toner image transferred to the transfer paper is separated from the photosensitive drum together with the transfer paper and is fixed on the transfer paper via a fixing device. At this time, the toner image, that is, the toner is melted by the heat of the heater of the fixing device. The melted toner penetrates between the fibers of the transfer paper, so that the paper and the toner are firmly adhered to each other and are discharged as a copy.

By the way, the illuminating device for illuminating an original is roughly classified into an incandescent lamp (including a halogen lamp) and a fluorescent lamp, and the wavelength characteristics of the light emitted from each lamp are output at a specific wavelength. It has a peak. Particularly when an incandescent lamp or halogen is used, the ratio of wavelengths including red is high, and red light is substantially provided to the sensitivity of the photosensitive drum. Therefore, in many copying apparatuses, a filter for cutting red light is arranged between the illuminating device and the photoconductor drum to reduce the ratio of red light contained in the illuminating light, thereby achieving uniform color ( Wavelength) A method of giving reproducibility is used.

On the other hand, the photosensitive drum is selenium.
The photoconductors are roughly classified into inorganic photoconductors represented by (Se) type and alumophous silicon (a-Si) and organic photoconductors (OPC), and each photoconductor has its own wavelength sensitivity. In particular, it is known that the OPC photoconductor has low sensitivity to red light.

[0006]

However, this means that, for example, when copying an image of a document on which a seal is impressed, that is, a red image of red ink is included, a black image which is a character portion is formed. In comparison, there is a problem that the imprint due to red ink, that is, the image of a red image, that is, deterioration or the blurring of the image occurs.

Further, cutting the red light guided to the photosensitive drum substantially lowers the total light amount of the white light which is the illumination light, so that the illuminating device necessary for increasing the total light amount. That is, the voltage or active power applied to the lamp is increased. This increases the power consumption and the temperature rise, but has the problem of reducing the surplus power. An object of the present invention is to provide an image forming apparatus that can provide uniform color reproducibility.

[0008]

SUMMARY OF THE INVENTION The present invention has been made based on the above problems, and includes a first light detecting means for detecting light corresponding to information, and a first light detecting means for detecting at least a part of the light. Second light detection means, illumination means for generating the light, based on the output from the first and second light detection means, the determination means for determining the state of the image information, the An image forming apparatus having an urging unit that urges the illuminating unit in accordance with a control amount defined based on the determination result of the determining unit.

According to the invention, the illumination means for illuminating the document, the image carrier on which an image corresponding to the light and shade of the reflected light from the document obtained by illuminating the information of the document is formed, Between the image carrier and the illumination means,
The first detection means, which is arranged at a predetermined position in the plane including the chief ray of the reflected light guided from the illuminating means to the image carrier, and detects the ratio of the contrast of the reflected light, and the image carrier. Between the body and the illuminating means, the illuminating means is disposed at a predetermined position in a plane including the chief ray of the reflected light guided to the image carrier, and has a predetermined color of the reflected light. Second detecting means for detecting the corresponding light and dark ratio, based on the output from the first and second detecting means, a calculating means for calculating the ratio of the predetermined color included in the information, There is provided an image forming apparatus having an urging means for urging the illuminating means in correspondence with a control amount defined based on the result of the operation by the arithmetic means.

Further, according to the present invention, an illuminating means for illuminating the document, an image carrier on which an image corresponding to the brightness of the reflected light from the document obtained by illuminating the information of the document is formed, and Between the image carrier and the illuminating means, it is arranged at a predetermined position in the plane including the chief ray of the reflected light guided from the illuminating means to the image carrier, and the brightness of the reflected light is changed. A ratio, between the first and second photoelectric conversion means for outputting the light and dark information as a numerical value corresponding to the light and dark information obtained by photoelectrically converting the light and dark information, between the image carrier and the illuminated light means. Is arranged at a predetermined position in a plane including the chief ray of the reflected light guided from the illuminating means to the image carrier, and the ratio of light and dark corresponding to a predetermined color of the reflected light is Photoelectric conversion of light and dark information according to brightness A second photoelectric conversion means for outputting a value corresponding to the brightness information obtained Ri, based on the output that is output from the first and second detection means,
It has a calculation means for calculating the ratio of a predetermined color included in the information, and a biasing means for biasing the illumination means in correspondence with a control amount defined based on the result of the calculation by the calculation means. An image forming apparatus is provided.

Further, according to the present invention, an illuminating means for illuminating the original, and an image carrier on which an image corresponding to the brightness of the reflected light from the original obtained by illuminating the information of the original is formed. A first detection element which is arranged at a predetermined position within a plane including the chief ray of the reflected light guided from the illumination means to the image carrier and which detects a first density corresponding to all information of the original. And a first detection element, which has filter means for blocking passage of light of a predetermined wavelength on a light incident surface of the detection element substantially the same, and information corresponding to information of a predetermined color of the original is removed. An image content monitoring means including a second detection element for detecting a density of 2; and a computing means for computing a ratio of a predetermined color included in the information based on an output result of the image content monitoring means, Based on the result of the calculation by this calculation means In response to the control amount defined, the image forming apparatus is provided with a biasing means for biasing said illuminating means. Furthermore, according to the present invention, the illumination means for illuminating the original document, the voltage supply means for supplying a predetermined voltage for turning on the illumination means, and the reflection from the original document obtained by illuminating the information of the original document. Between a photoconductor on which an image corresponding to the light and shade of light is formed, and between the photoconductor and the illuminating means, and in a plane including the chief ray of the reflected light guided from the illuminating means to the photoconductor. Is arranged at a predetermined position, the ratio of the brightness of the reflected light, the first photoelectric conversion means for outputting as a numerical value corresponding to the brightness information obtained by photoelectrically converting the brightness information according to the brightness, and Between the photoconductor and the illuminating means, disposed at a predetermined position in a plane including the chief ray of the reflected light guided from the illuminating means to the photoconductor, and having a predetermined light incident surface. A filter that blocks the passage of light of a certain wavelength A second photoelectric device that has a means and outputs the ratio of light and dark corresponding to a predetermined color of the reflected light as a numerical value corresponding to the light and dark information obtained by photoelectrically converting the light and dark information according to the brightness. The conversion means, Vn, the output of the first detection means, Vr,
The output of the second detection means, Vd, the relative density of the information including the ratio of the predetermined color included in the information, α, the reflected light from the area other than the predetermined color in the document is the second In addition, when the reciprocal of the ratio attenuated by the filter means of the detection means and β are coefficients for correcting the difference in sensitivity of the photoconductor and the first detection means with respect to the predetermined color, Vd = Vn + β (Vn−αVr), a calculation means for calculating the relative density of a predetermined color included in the above information, Vcnt, a drive voltage to be supplied to the illumination means, and Vc from the voltage supply means. A fixed value of the voltage supplied to the illuminating means, Aat is a constant for correcting the deviation in sensitivity between the first detecting means and the second detecting means, and Am is a light emission characteristic of the illuminating means. To correct deviations Where Vcnt = (Vc−AatVd) Am, an image forming apparatus having a driving unit that drives the illuminating unit is provided.

[0012]

According to the image forming apparatus of the present invention, the output from the first light detecting means for detecting the light corresponding to the information and the second light detecting means for detecting at least a part of the light corresponding to the information is output. Based on the state of the image information determined by the determination means based on the control amount, the control amount for urging the illumination means is defined.

Further, in the image forming apparatus of the invention, the first detecting means and the second detecting means are arranged in a plane including the principal ray of the light guided from the illuminating means to the image carrier, respectively. The second detecting means has a filter means for blocking passage of light having a wavelength corresponding to information of a predetermined color,
The first density corresponding to all the information of the document and the second density obtained by removing the information corresponding to the information of the predetermined color of the document are detected, and the ratio of the predetermined color included in the information is calculated. After being calculated by the means, the control amount for activating the lighting means is defined based on the calculation result by the calculating means.

Therefore, it becomes possible to detect the existence of the area containing the information of the predetermined color, and when the area containing the information of the predetermined color exists, the voltage supplied to the illumination means can be optimally controlled.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. According to FIG. 1, an image forming apparatus or copying apparatus 2
Is an original table 10 on which an object to be copied, that is, an original D is placed, and an original presser which is formed to be openable and closable with respect to the original table 10 and makes the original D placed on the original table 10 adhere to the original table 10. Have twelve.

Below the document table 10, that is, inside the apparatus 2, an exposure lamp 14 for illuminating the document D placed on the document table 10, and a reflection for converging the illumination light generated by the exposure lamp 14 on the document D. The plate 16 and the first mirror 18 that bends the reflected light from the document D are integrally formed, and the first carriage 20 that reflects the reflected light from the document D in a predetermined direction is arranged.

The first carriage 20 is the original table 10.
It is arranged so as to be movable in parallel with and is reciprocated along the document table 10 by a pulse motor (not shown). The exposure lamp 14 is connected to a lamp regulator described later, and is turned on by a voltage from the lamp regulator adjusted corresponding to various light amounts corresponding to an exposure amount input from an operation panel (not shown).

In the direction in which the reflected light reflected by the first mirror 18 is guided, the second mirror 22 that sequentially bends the reflected light from the document D bent via the first mirror 18.
And the third mirror 24 is arranged at right angles to each other.
The second mirror 22 and the third mirror 24 are fixed to the second carriage 26.

The second carriage 26 is the first carriage 2.
While being driven by the first carriage 20 by a toothed belt or the like (not shown) that drives 0, it is moved parallel to the original table 10 at a speed of ½ with respect to the first carriage 20.

Below the first carriage 20, in a plane including the optical axis of the light reflected by the second carriage 26, it is movably formed by a driving mechanism (not shown). An image forming lens 28 that imparts a converging property to the reflected light from 26 and forms an image of the reflected light at a predetermined magnification by moving itself, and is arranged at right angles to each other and corresponds to the predetermined magnification by the lens 28. The optical path of the reflected light having the converging property is further folded back, and the optical path length, that is, the change in the distance between the original table 10 and the photosensitive drum, which will be described later, due to the movement of the lens 28 itself moves. Thus, the fourth mirror 30 and the fifth mirror 32 for correction are arranged. In addition,
The fourth mirror 30 and the fifth mirror 32 are held by the mirror holding frame 34.

In the direction in which the reflected light reflected by the fifth mirror 32 is guided, a folding (exposure) mirror 3 for focusing the reflected light at a predetermined position on the photosensitive drum, which will be described later.
6 and the like are arranged. Note that the folding (exposure) mirror 36 is, like the imaging lens 28, arranged along the optical axis of the lens 28 via a driving mechanism (not shown) in order to correct the variation of the focal length which is changed according to the copy magnification. It is formed to be movable.

In the same plane in which the lens 28 is arranged
(Indicated by a chain double-dashed line in FIG. 2), that is, in a region through which the light transmitted from the third mirror 24 to the fourth mirror 30 passes and which does not block the light traveling to the fourth mirror 30. Is an automatic exposure sensor (hereinafter referred to as AES) 38 for detecting the density of the image information of the document D in order to maintain the image density of the copy obtained by the copying operation at a constant level.
And a red image detection sensor (hereinafter referred to as RIS) 40 for detecting the presence / absence of a red image in the image information of the document D (see FIG. 2).
(See) is fixed via a fixing member (not shown).
The AES 38 and RIS each generate an analog voltage corresponding to the light intensity of the input light, that is, the amount of light by photoelectrically converting the input light.

A recording medium, that is, a photosensitive drum 42, on which an image corresponding to the image of the original is formed by the light transmitted through the folding (exposure) mirror 36, is arranged at approximately the center of the copying apparatus 2. . This photosensitive drum 42
Is rotated in the direction of the arrow at a predetermined speed by a motor (not shown).

Around the photosensitive drum 42, a charging device 44 for charging the drum 42 with a predetermined electric charge along the direction in which the photosensitive drum 42 is rotated, and a paper size input through an operation panel (not shown). Alternatively, a peripheral area erasing LED 46 for erasing electric charges on the drum 42 corresponding to the outside of the image forming area corresponding to the image forming magnification, and a developing device 48 for developing by supplying toner to the electrostatic latent image formed on the drum 42. A transfer device 50 that transfers the toner image formed on the drum 42 to a sheet, and a cleaning static eliminator 52 that scrapes off the toner remaining on the surface of the drum 42 and removes the electric charges remaining on the surface of the drum 42. They are arranged in order. The transfer device 50 is integrally formed with a separating device 51 for separating the sheet electrostatically adsorbed by the drum 42 from the drum 42 when the toner image is transferred.

The image formed on the photosensitive drum 42, that is, the toner image is transferred to the position corresponding to the upstream side in the direction in which the photosensitive drum 42 is rotated, that is, to the right of the apparatus 2 in this embodiment. First and second holding paper for storage
Paper cassettes 54a and 54b are detachably held by slots 56a and 56b.

Between the photosensitive drum 42 and the slot 56a (cassette 54a), a paper feed roller 58a for pulling out the paper one by one from the paper cassette 54a, and a paper feed roller 58a and a paper feed roller 58b are drawn out. Conveying roller 60a for sending the formed sheet to the photosensitive drum 42
Is arranged. Similarly, between the photoconductor drum 42 and the slot 56b (cassette 54b), the paper feed roller 58b that draws the paper one by one from the paper cassette 54b, and the paper that is drawn through the paper feed roller 58b is exposed. A transport roller 60b for delivering to the body drum 42 is arranged.

Between the photosensitive drum 42 and each of the conveying rollers 60a and the conveying rollers 60b, the inclination of the paper taken out from each cassette is corrected, and the tip of the toner image on the photosensitive drum 42 and the paper A timing roller 62 that aligns the leading end and feeds the paper at the same speed as the moving speed of the outer peripheral surface of the photosensitive drum 42 is arranged.

At a position corresponding to the downstream side of the transfer device 50 along the direction in which the photosensitive drum 42 is rotated, a conveying device 64 for conveying the sheet on which the toner image formed on the photosensitive drum 42 is transferred, It has a fixing device 66 that melts the toner transferred onto the paper by heating and fixes it on the paper, and a pair of discharge rollers 68 that discharge the paper on which the toner image is fixed to the outside of the apparatus 2.

The fixing device 66 includes a pair of heat rollers whose roller surfaces are in pressure contact with each other, and heats the toner held on the paper when the paper passes between the roller saws to melt the toner image. The toner image is fixed to the paper by pressing the toner image and the paper.

FIG. 2 shows an automatic exposure sensor (AES) 38.
Also, the relationship between the red image detection sensor (RIS) 40 and the light reflected by the third mirror 24 is shown. Figure 2
As is apparent from the above, the reflected light from the document D reflected by the third mirror 24 includes the optical axis O of the lens 26 and is defined by the optical axis O and the light reflected by the third mirror 24. It is guided to a fourth mirror 30 (not shown in FIG. 2) through a plane (shown by a chain double-dashed line) 26p.

The AES 38 and the RIS 40 are planes 2 that do not block the light passing through the lens 26, respectively.
It is arranged at an arbitrary position on 6p. So, for example,
The AES 38 and the RIS 40 shown in FIG. 2 may be arranged in opposite positions, respectively. Also, AES38
The RIS 40 and the RIS 40 may be arranged in parallel on one side of the lens 26.

Note that the RIS 40 is a sensor unit in which a filter for cutting red light and a light amount sensor are combined, and the filter 40b is substantially the same as the AES 38 on the light incident surface side of the automatic exposure sensor 40a. It is a sensor arranged.

FIG. 3 schematically shows the electrical connections between the components of the copying machine and the various electrical circuits. According to FIG. 3, CP as a control device
U70 (details of which are shown in FIG. 4) is a ROM 72a in which data necessary for operating the device 2 and a surface potential control routine described later are written in advance,
RAM 72b used for temporarily storing the number of copies or numerical data of the copy magnification input through an operation panel (not shown), and adjustment data or total number of copies input through an operation panel (not shown) Is connected to a non-volatile memory 72c for storing the.

The CPU 70 also includes an AES automatic exposure sensor) 38 and a RIS (red image detection sensor) 40.
A / D converter (input circuit) 74 for inputting an analog signal from the CPU 70 to the CPU 70, a D / A converter (output circuit) for converting a digital control amount instructed by the CPU 70 into an analog signal and outputting the analog signal to a corresponding device or electric circuit. ) 76, and an interface 78 for transmitting data input from an operation panel (not shown) to the CPU 70 and supplying an output (such as data display) corresponding to an instruction from the CPU 70 to the operation panel.

The CPU 70 is provided with an input port (not shown) to which sheet detection signals output from many sheet position detection switches (not shown) are input, and a mechanical unit (not shown) that energizes many solenoids or electromagnetic clutches (not shown). Needless to say, it is also connected to the controller.

The D / A converter 76 supplies a predetermined voltage to the lamp regulator 80, the charging device 44 and the transfer device 50, which changes the lamp voltage applied to the illumination lamp 14 according to the control amount instructed by the CPU 70. A high voltage supply unit 82, a charging device 44, a developing device 48, and a transfer device 50 are connected to a bias voltage supply unit 84 that supplies a predetermined bias voltage, an AC voltage generation unit 86 that supplies an AC electric field to the separator 51, and the like. There is.

Next, the copying apparatus 2 according to the embodiment of the present invention.
The operation of will be described in detail. When the power switch (not shown) is turned on, the apparatus 2 is warmed up and a standby (copyable) state is defined.

The number of copies, via an operation panel (not shown),
Copy condition data such as copy magnification, enlargement / reduction, paper size selection, or mode selection is input,
When a copy start signal is input from a copy start key (not shown), the copy operation of the image of the document D placed on the document table 10 is started.

That is, after the illumination lamp 14 is turned on by supplying the voltage corresponding to the instruction from the CPU 70 from the lamp regulator 80, the first carriage 20 and the second carriage 2 are driven by the scanning motor (not shown).
By moving 6 along the document table 10, the reflected light (that is, image information) from the document D placed on the document table 10 is sequentially transmitted to the photosensitive drum 42.

At the same time, a part of the reflected light of the illumination light from the illumination lamp 14 reflected by the original D is reflected on the plane 26p by A
The light enters the ES 38 and the RIS 40 and is converted into an analog voltage corresponding to the light amount of the input light, that is, the light intensity.

The analog voltages from the AES 38 and the RIS 40 are converted into digital signals via the A / D converter 74, and then input to the input ports A / D0 and A / D1 (see FIG. 4) of the CPU 70. .

FIG. 5 shows the relationship between the image densities of the original document D having images having different image densities and the output voltages from the AES and RIS. For example, document D
As shown in FIG. 5A, the image density of the image information of
When the first and second carriages 20 and 26 sequentially change along the moving direction, that is, the document scanning direction,
The output voltage Vr from the RIS 40 is obtained by filtering the output voltage Vn from the AES 38 with the filter 4 as shown in FIG.
The light quantity attenuated by the density of 0b is output in a state of being attenuated at an equal ratio with the difference being the light quantity. In addition, the output voltage Vr of the RIS 40 is obtained by filtering the light reflected from the area of the red image by the filter 4.
Since it is absorbed at 0b, the output voltage Vn of the AES 38 is significantly reduced only in the section corresponding to the area of the red image.

Next, a method of defining the output voltage from the lamp regulator 80 applied to the illumination lamp 14 will be described. Since the reflected light from the document D is incident on both the AES 38 and the RIS 40, first, the output instruction voltage Vcnt supplied to the lamp regulator 80.
The image density voltage Vd used to calculate
70.

The density voltage Vd is α, the reciprocal of the ratio of the reflected light from the area other than the red color of the original being attenuated by the filter 40b, and β is the photosensitive drum 42 and AE.
When S38 is used as a coefficient for correcting the difference in sensitivity to red, it is derived by Vd = Vn + β (Vn−αVr). The constant α, that is, the reciprocal of the rate at which the light amount is attenuated by the filter 40b is generally “Vn−” for a normal document, that is, a document not including a red image.
αVr = 0 ”is satisfied. In addition,
“Vn−αVr” indicates the size of the image area of the red image included in the document D, that is, the amount of the red image,
Needless to say.

The constant β, that is, the coefficient for correcting the difference in sensitivity between the drum and the AES for red color is, for example,
It is obtained as a deviation obtained from a numerical value obtained experimentally or empirically, and is stored in the ROM 72a in advance.
The constant β may be set in the non-volatile memory 72c after being set by the adjustment work at the time of assembly.

As is apparent from FIG. 5 (c), the concentration voltage Vd is between the maximum value and the minimum value of the voltage, which is higher than the voltage of either Vn or Vr shown in FIG. 5 (b). The band or width is narrow and the deviation (voltage change) is uniform.

By referring to Vd thus obtained, the output instruction voltage Vcnt to the lamp regulator 80 which outputs the voltage to be applied to the illumination lamp 14 is C
The PU 70 sets Vc to a fixed value, Aat, which is defined in advance based on the voltage-light emission characteristics of the illumination lamp 14.
Can be adjusted within a predetermined range, and a constant for correcting the deviation of the sensitivity of the AES 38 and the RIS 40, and Am can be adjusted within a predetermined range, and the voltage-light emission of the illumination lamp 14 can be adjusted. Vcnt = (Vc-AatVd) Am is used as a constant for correcting the characteristic deviation (see FIG. 5D).

The output instruction voltage Vcnt to the lamp regulator 80 thus obtained is output from the output ports D0 to D7 of the CPU 70 to the D / A converter 76 as an 8-bit digital signal and then to the D / A converter 76. The illumination lamp 14 is turned on by the connected lamp regulator 80.

The red image area of the document D can be similarly detected by preparing a sensor having no sensitivity to red as the sensor 40a in the RIT 40 and replacing the red filter 40b with an infrared transmissive filter. In this case, A
The output Vn of the ES 38 and the output Vr of the RIT 40 are almost the same output in the red image area.

Next, for comparison, assuming that only the AES 38 is used, the output instruction voltage Vcnt (AE
Similarly, if S) is obtained with the concentration voltage Vd = sensor output Vn, Vcnt (AES) = (Vc−AatVn) Am is satisfied.

Referring to FIG. 5D, Vcnt and Vcn
When compared with t (AES), the output instruction voltage Vcnt to the lamp regulator 80 obtained by the present invention is
In the area where the red image is present, a low voltage similar to the lamp voltage provided for the white (no image) area is indicated. Therefore, it is possible to prevent the red image, for example, the imprint imprinted with red ink from fading.

Further, the total amount of light provided to all the image areas of the document D, that is, the integrated value of the output instruction voltage (see FIG. 5).
Since the area of the region surrounded by the curve Vcnt and the time axis and the voltage axis in (d) is smaller than Vcnt (AES), the power consumption can be reduced. At the same time, this can prevent the temperature of the document table 10 from rising due to the light from the illumination lamp 14.

On the other hand, in parallel with the above-described image density detection, a motor (not shown) is energized to rotate the photosensitive drum 42 at a desired speed. At the same time, the charging device 4
When a predetermined voltage is applied to the photosensitive drum 4, a predetermined amount of electric charge is supplied to the photosensitive drum 42 by corona discharge.

In this state, the first to third mirrors 18, 22 and 2 are illuminated by the light from the illumination lamp 14.
4, lens 28, fourth and fifth mirrors 30 and 3
2 and the reflected light of the document D transmitted through the folding (exposure) mirror 36 is imaged on the surface of the photoconductor drum 42 to form an electrostatic latent image corresponding to the image of the document D. It

The electrostatic latent image formed in this manner is developed by the toner supplied through the developing roller 48a of the developing device 48 to which a predetermined developing bias voltage is applied, and then the timing roller 62 ejects it. It is transferred as a toner image onto the fed-out paper via the transfer device 50.

The toner image transferred to the sheet is separated from the surface of the photosensitive drum 42 together with the sheet, and then is conveyed to the fixing device 64 by the conveying device 62 and the fixing device 64.
It is fixed to the paper through. The sheet on which the toner image is fixed is sequentially ejected to the outside of the apparatus 2 via the ejection roller 66. Photosensitive drum 4 with toner image transferred on paper
No. 2 is rotated as it is, the residual toner is removed through the cleaning charge removal device 52, and then the charge is removed to be used for the next image formation. When the number of copies is two or more, or when the next original is supplied, the above series of copying operations are repeated.

[0057]

As described above, according to the image forming apparatus of the present invention, the first light detecting means for detecting the light corresponding to the information and the second light detecting means for detecting at least a part of the light corresponding to the information. The control amount for urging the illumination means is defined in accordance with the state of the image information determined by the determination means based on the output from the light detection means. Therefore, when the image of the original includes image information other than black, such as red, the control amount for activating the illumination means is optimally defined.

Further, in the image forming apparatus of the invention, the first detecting means and the second detecting means are arranged in the plane including the principal ray of the light guided from the illuminating means to the image carrier, respectively. The second detecting means has a filter means for blocking passage of light having a wavelength corresponding to information of a predetermined color,
The first density corresponding to all the information of the document and the second density obtained by removing the information corresponding to the information of the predetermined color of the document are detected, and the ratio of the predetermined color included in the information is calculated. After being calculated by the means, the control amount for activating the lighting means is defined based on the calculation result by the calculating means. Therefore, it becomes possible to detect the existence of the area including the information of the predetermined color, and when the area including the information of the predetermined color exists, the voltage supplied to the illumination unit can be optimally controlled. As a result, even if the image of the document includes image information such as a red imprint of red ink other than black, it is possible to prevent the imprint from fading.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a copying machine in which an embodiment of the present invention is incorporated.

2 is a schematic diagram showing an example of a position and a signal output circuit of an automatic exposure sensor of the copying apparatus shown in FIG.

FIG. 3 is a schematic block diagram showing an example of a control unit of the copying apparatus shown in FIG.

FIG. 4 is a schematic diagram and a block diagram showing an example of outputs from the automatic exposure sensor and the red detection sensor shown in FIG. 2 and an output of a control amount to a lamp regulator.

FIG. 5 is a diagram showing the relationship between the image density of a document and the outputs of an automatic exposure sensor and a red detection sensor,
Is a plan view showing the density distribution in the original, (b) is a graph showing the output of the automatic exposure sensor corresponding to the image density of the original and the output of the red detection sensor corresponding to the image density of the original, (c) is , A graph showing relative densities of predetermined colors obtained from respective outputs of the automatic exposure sensor and the red detection sensor, and (d) is a graph showing a control amount for defining the voltage supplied to the illumination lamp.

[Explanation of symbols]

2 ... Copying device (image forming device), 10 ... Original table,
12 ... Original pressing, 14 ... Illumination lamp, 16 ... Reflector,
18 ... 1st mirror, 20 ... 1st carriage, 22 ... 2nd
Mirror, 24 ... Third mirror, 26 ... Second carriage, 2
8 ... Imaging lens, 30 ... Fourth mirror, 32 ... Fifth mirror, 34 ... Holding frame, 36 ... Folding mirror, 38 ... Automatic exposure sensor (AES), 40 ... Red image detection sensor (RI
S), 42 ... Photosensitive drum, 44 ... Charging device, 46 ... Peripheral area erasing LED, 48 ... Developing device, 50 ... Transfer device,
52 ... cleaning static eliminator, 54a, 54b ... paper cassette slot, 56a, 56b ... slot, 58a,
58b ... Paper feeding roller, 60a, 60b ... Conveying roller, 6
2 ... Timing roller, 64 ... Conveying device, 66 ... Fixing device, 68 ... Ejecting roller, 70 ... CPU, 72 ... Memory,
72a ... ROM, 72b ... RAM, 72c ... nonvolatile memory, 74 ... A / D converter (input circuit), 76 ... D
/ A converter (output circuit), 78 ... Interface,
80 ... Lamp regulator, 82 ... High-voltage supply unit, 84
... bias voltage supply unit, 86 ... AC voltage generation unit.

Claims (5)

[Claims] 1. A first light detecting means for detecting light corresponding to information, a second light detecting means for detecting at least a part of the light, an illuminating means for generating the light, The determination means for determining the state of the image information based on the output from the first and second light detection means, and the illumination corresponding to the control amount defined based on the determination result by the determination means And an urging unit for urging the unit. 2. An illuminating means for illuminating an original, an image carrier on which an image corresponding to the brightness of reflected light from the original obtained by illuminating information on the original is formed, the image carrier and the illumination. A first means for detecting the ratio of light and darkness of the reflected light, which is disposed between the means and a predetermined position within a plane including the chief ray of the reflected light guided from the illumination means to the image carrier. Of the detection means, between the image carrier and the illuminating means, disposed at a predetermined position in a plane including the chief ray of the reflected light guided from the illuminating means to the image carrier, Second detection means for detecting the ratio of brightness and darkness corresponding to the predetermined color of the reflected light, and based on the output output from the first and second detection means, of the predetermined color included in the information The calculation means for calculating the ratio and the result of the calculation by this calculation means In response to the control amount defined in Zui, and urging means for urging said illuminating means,
An image forming apparatus having. 3. An illumination means for illuminating an original, an image carrier on which an image corresponding to the brightness of reflected light from the original obtained by illuminating information on the original is formed, the image carrier and the illumination. Between the means and the illumination means is arranged at a predetermined position in the plane including the chief ray of the reflected light guided to the image carrier, and the ratio of the light and dark of the reflected light is the light and dark information. Between the image carrier and the illuminating means, the first photoelectric converting means outputting as a numerical value corresponding to the brightness information obtained by photoelectrically converting according to the brightness from the illuminating means. Arranged at a predetermined position in a plane including the chief ray of the reflected light guided to the image carrier, the ratio of light and dark corresponding to a predetermined color of the reflected light, the light and dark information according to the brightness. The light and dark information obtained by photoelectric conversion Second photoelectric conversion means for outputting a corresponding numerical value, and operation means for calculating a ratio of a predetermined color included in the information based on the outputs output from the first and second detecting means, Urging means for urging the illuminating means, corresponding to a control amount defined based on the result of the calculation by the calculating means,
An image forming apparatus having. 4. An illuminating means for illuminating an original, an image carrier for forming an image corresponding to light and shade of reflected light from the original obtained by illuminating information on the original, and the illuminating means for carrying the image. A first detection element and a first detection element which are arranged at a predetermined position in a plane including the chief ray of the reflected light guided to the body and which detect a first density corresponding to all information of the original; Filter means for blocking passage of light of a predetermined wavelength on the light incident surfaces of the detection elements that are substantially equal to each other, and detecting the second density from which information corresponding to information of a predetermined color of the original is removed Including two detection elements,
An image content monitoring means, a computing means for computing a ratio of a predetermined color included in the above information based on an output result of the image content monitoring means, and a control amount defined based on a result of the computation by the computing means. Corresponding to, urging means for urging the lighting means,
An image forming apparatus having. 5. Illuminating means for illuminating an original, voltage supply means for supplying a predetermined voltage for illuminating the illuminating means, and light and dark of reflected light from the original obtained by illuminating information of the original. A photoconductor on which a corresponding image is formed, and a predetermined position in a plane between the photoconductor and the illuminating means, the plane including the chief ray of the reflected light guided from the illuminating means to the photoconductor. A first photoelectric conversion means for outputting the ratio of the brightness of the reflected light as a numerical value corresponding to the brightness information obtained by photoelectrically converting the brightness information according to the brightness; and the photoconductor. Between the illuminating means and the illuminating means, the illuminating means is disposed at a predetermined position in a plane including the chief ray of the reflected light guided to the photoconductor, and a light incident surface of the light having a predetermined wavelength. With filter means to prevent passage, A second photoelectric conversion means for outputting a ratio of lightness and darkness corresponding to a predetermined color of the reflected light as a numerical value corresponding to the lightness / darkness information obtained by photoelectrically converting the lightness / darkness information according to the brightness; Is the output of the first detection means, Vr is the output of the second detection means, Vd is the relative density of the information including the ratio of the predetermined color included in the information, and α is the The reciprocal of the ratio at which the reflected light from the area other than the predetermined color is attenuated by the filter means of the second detection means, and β are the sensitivity of the photoconductor and the first detection means to the predetermined color. Is a coefficient for correcting the difference between Vcnt and Vcnt, and Vcnt is supplied to the illuminating means by Vd = Vn + β (Vn−αVr). Drive voltage, Vc is a fixed value of the voltage supplied from the voltage supply means to the illumination means, Aat is a constant for correcting the deviation of the sensitivity of the first detection means and the second detection means, and Am. Is a constant for correcting the deviation of the light emission characteristic of the illuminating means, and Vcnt = (Vc-AatVd) Am, and a driving means for driving the illuminating means.