JP2915199B2 - Electrophotographic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus provided with a photoreceptor.

[0002]

2. Description of the Related Art In a copying machine as an electrophotographic apparatus, an original image is irradiated with light by a copy lamp, a photosensitive member is charged to a predetermined potential by a main charger, and the photosensitive member is reflected from the original image. A desired image is obtained on a transfer paper by irradiating light to form an electrostatic latent image, developing the electrostatic latent image with toner, and transferring the resulting toner image to transfer paper. It has become. In such a copying machine, for example, as disclosed in Japanese Patent Publication No. 3-14186, the density of a toner image formed on a photoreceptor is monitored by a density sensor, and the copy density and white , The image forming conditions such as the voltage applied to the copy lamp, that is, the copy lamp voltage, the main charger voltage, and the developing bias are adjusted.

The above-mentioned photoconductor is a consumable item, and is replaced when the reduction of the charged potential and the residual potential becomes large, or when the thickness of the photosensitive layer becomes thin. I have.

However, when the photoconductors are supplied from a plurality of different manufacturers, the characteristics of the photoconductors are slightly different due to the difference in the pigment of the pigment layer (CGL layer). Appropriate image forming conditions are defined for each body. Therefore, when the photoconductor is replaced with a different type of photoconductor from the one used so far, the specified value of the above-described image forming conditions must be changed. In this case, although the image density can be adjusted to some extent by the adjustment function based on the above-mentioned conventional density sensor, it is not possible to cope with the case where the characteristics of the photoconductors are largely different. For this reason, the serviceman has to perform the adjustment by a manual operation, and the non-operation time of the copying machine associated with the exchange work of the photoconductor increases.

Further, depending on the photoconductor and the copying machine to be replaced, there is a limit to the adjustment by manual operation by a service person. For example, when the copying machine is used in a state where the specified values of the image forming conditions are not properly set, not only is it not possible to obtain a proper copied image, but also there is a risk that toner may be scattered or the apparatus may be damaged. is there.

Therefore, in order to solve these problems,
The inventors of the present application have previously filed an application for Japanese Patent Application Laid-Open No. Hei 5-188708 (Japanese Patent Application No. 4-3810). In the above-mentioned application, a color sensor, which is a color detection unit, detects the color of the photoreceptor with light reflected from the photoreceptor of light emitted from the light emitting element, and control means detects the color of the photoreceptor based on the output of the color sensor. The type is determined, and the image forming operation is performed under the image forming conditions corresponding to the determined type of the photosensitive member among the image forming conditions stored in the storage unit in advance.
At least one image forming device is controlled. Further, the control means determines the photoreceptor, and determines whether or not the image forming condition set in the image forming apparatus can be adjusted so as to correspond to the determined type of photoreceptor. When it is not possible, the notifying unit is operated to notify the inappropriateness of the photoconductor.

Accordingly, when the photosensitive member is replaced, the image forming condition set in at least one image forming apparatus is automatically changed, so that the non-operating time of the apparatus due to the replacement of the photosensitive member is reduced. In addition, by operating the apparatus with an inappropriate photoreceptor mounted, it is possible to avoid a situation in which toner is scattered or the apparatus is damaged.

[0008]

However, in the above configuration, a halogen lamp is used as a light emitting element,
When the color tone of the photoconductor is read by the color sensor, the reading of the color sensor is likely to be inaccurate. Based on this, the type of the photoconductor is determined by the control unit, and the control of the image forming member and the inappropriate Since the wearing of the body is detected,
Accurate control and detection are not performed, and the effect of reducing the non-operating time of the apparatus due to the replacement of the photoconductor and preventing toner scattering caused by improper mounting of the photoconductor is not effectively obtained. Has problems.

The halogen lamp is usually 400 to 1000
It emits light having a wavelength on the order of nm and generates a large amount of heat energy together with light energy. This means that the ratio of near-infrared light having a wavelength of about 800 nm or more to the amount of light emitted from the halogen lamp is high. On the other hand, a color sensor has a characteristic that, when visible light and near-infrared light are simultaneously incident, short-wavelength visible light is detected longer than the actual wavelength. Therefore, when the light of the halogen lamp is irradiated on the photoconductor and the color sensor receives the reflected light from the photoconductor and detects the color of the photoconductor, the ratio of the near infrared light is high. Even short-wavelength light emitted at the same time is easily detected as long-wavelength near-infrared light, and reading by the color sensor becomes inaccurate.

Therefore, the present invention provides a photoconductor type detecting means comprising a light emitting element and a color sensor suitable for detecting the color of the photoconductor in a copying machine, and accurately detects the type of the photoconductor. The control means identifies the type of photoreceptor, controls the image forming member according to the type of photoreceptor, and detects improper mounting of the photoreceptor. It is an object of the present invention to provide a copying machine capable of effectively obtaining the effect of shortening and preventing toner scattering caused by improper mounting of a photoconductor.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an electrophotographic apparatus according to the present invention emits light to a photoconductor in order for a control unit to identify a type of photoconductor incorporated in the main body of the electrophotographic apparatus. An electrophotographic apparatus provided with a photoreceptor type detection unit including a light-emitting element for irradiation and a color detection unit having a light-sensitive element that responds to reflected light from the photoreceptor, wherein the photoreceptor type detection unit is Based on light detection signals output by the plurality of light-sensitive elements having different spectral sensitivity characteristics in response to light reflected from the photoconductor,
It is characterized by outputting an output voltage having a one-to-one relationship with the wavelength of the light reflected from the photoreceptor.

Further, the electrophotographic apparatus may include the photoconductor.
Type detection means absorbs infrared light from the light incident on the photoreceptor.
It is characterized by having an infrared absorption filter
I have.

[0013]

SUMMARY OF] According to the above configuration, the photoconductor type detecting means of the electrophotographic apparatus, the partial color detector light reflected from the photosensitive member
Receives light with multiple photosensitive elements with different light sensitivity characteristics
And converts it to an output voltage corresponding to the wavelength of the light reflected from the photoconductor.
And outputs it to the control means. Then, the control unit of the electrophotographic apparatus to identify the type of the photosensitive body based on this. Yo
By controlling the image forming member according to the type of photoreceptor and detecting improper mounting of the photoreceptor, it is possible to reduce the non-operating time of the apparatus due to the replacement of the photoreceptor and to reduce the improper photoreceptor. It is possible to prevent toner scattering and the like caused by mounting.

Further, according to the above configuration, the electronic photographing is performed.
Infrared absorption filter provided in the photoconductor type detection means of the true device
Filter absorbs infrared light emitted from the light-emitting element.
Therefore, only visible light enters the color detection unit. Therefore, color inspection
The color of the photoreceptor can be accurately read by the photosensitive element
Can identify the type of photoreceptor more accurately.
it can. Therefore, the image forming unit according to the type of the photoreceptor
Control of materials and detection of improper photoconductor mounting.
The non-operating time of the device due to photoreceptor replacement,
Prevents toner scattering caused by mounting an appropriate photoconductor
Effect can be obtained effectively.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 2, the copying machine as an electrophotographic apparatus according to the present embodiment has a transparent document table on the upper surface of the copying machine body 1, and the document table is provided with An automatic document feeder 27 and a document cover 26 for supplying a document to be placed on a document table are provided. An optical system 2 is provided below the document table. The optical system 2 irradiates light to the document placed on the document table, and a reflected light from the document. A plurality of reflecting mirrors 4, 5, 6, 7 guided on the photoreceptor 21 as shown by a dashed line.
And a zoom lens 8 disposed on the optical path.

Below the optical system 2, there is disposed a photosensitive member 21 to which the above-mentioned reflected light is irradiated.
A main charger 22 for charging the photoconductor 21, a developing device 23 for attaching toner to the photoconductor 21, a photoconductor 21
Transfer device 2 for transferring the toner image formed on the transfer paper
And a static eliminator 25 for removing the charge on the photoconductor 21.

On the side where the transfer paper is supplied to the photoreceptor 21, a paper feed unit comprising a registration roller 31 for setting the supply timing of the transfer paper and a plurality of paper feed cassettes capable of accommodating transfer paper of each size. 30 are provided. Further, on the side where the transfer paper is carried out from the photoconductor 21, a belt-shaped transport device 32 for placing and transporting the transfer paper, and a fixing unit 33 for heating and melting and fixing the toner transferred to the transfer paper are provided. And a plurality of discharge trays 34 on which transfer paper on which a copy image is formed can be placed in units of a plurality of sheets. Further, below the photoreceptor 21, an intermediate tray 36, a paper feed roller 38, and a reversing unit 37 used for performing double-sided copying or composite copying are disposed via a sheet transport path 35.

In the above copying machine, as shown in FIG. 1, the control means of an image forming apparatus and a notification unit 65, which will be described later, is RO
It is controlled by a control system having a master CPU 40 configured together with M42 and a slave CPU 41 that controls the optical system 2 and the like.

The slave CPU 41 has a ROM 44
In accordance with a program stored in advance in the rotary encoder (R)
E) A signal from 45 and a signal from a home position sensor (not shown) are received, the rotation of the motor 18 of the optical system 2 is controlled via the driver 46, and the registration roller 31 of FIG. A signal or the like for instructing the transfer paper supply timing is transmitted.

The master CPU 40 includes a main charger 22, a copy lamp 3, and a developing unit 23 for performing one cycle of charging, exposure, development, transfer, and charge elimination associated with an image forming operation in the copying machine. , A transfer unit 24 and a static eliminator 25 are connected. These units constitute an image forming apparatus together with a predetermined voltage generating unit, and are connected to the master CPU 40 via the voltage generating unit.
The operation is controlled by a control signal output from 40. FIG. 1 shows a charging unit 5 that supplies a high voltage to the main charger 22 among these voltage generating units.
0, a copy lamp lighting circuit 43 for setting the light amount of the copy lamp 3 is shown. In addition, the master CPU 40
A photoreceptor type detector 53 which is a photoreceptor type detection means for detecting the color of the photoreceptor 21, that is, the type;
64 are connected.

The photoreceptor type detector 53 includes a light emitting element 52, an infrared cut filter 66 as an infrared absorption filter, a color sensor 51 as a color detector, and a color sensor signal processing circuit 61. The light emitting element 52, the infrared light cut filter 66, and the color sensor 51 are provided near the photoconductor 21 as shown in FIG. 2, and the light emitted from the light emitting element 52 as shown in FIG. The light is reflected by the surface of the photoconductor 21 via the infrared light cut filter 66 and is incident on the color sensor 51.

The light emitting element 52 includes 400 to 1
A halogen lamp that emits light having a wavelength of about 000 nm is used.

As the infrared light cut filter 66, for example, a Toshiba glass filter IRA-05 manufactured by Tokyo Shibaura Electric Co., Ltd. can be used. This glass filter IRA-05 is made of hard glass (linear expansion coefficient α = 60).
× 10 ⁻⁷ ), as shown in FIG. 4, the transmittance at 750 nm is 5%. Therefore, by arranging the infrared light cut filter 66 in the light path of the light emitted from the light emitting element 52 to the photoconductor 21, the infrared light having a wavelength of about 750 nm or more out of the light emitted from the light emitting element 52 is provided. Is absorbed by the infrared light cut filter 66, and only visible light having a wavelength of about 400 to 700 nm is transmitted, reaches the photoconductor 21, is reflected, and is reflected by the color sensor 51.
Is received.

As the color sensor 51, for example, a PD 152 manufactured by Sharp Corporation can be used. As shown in FIG. 5, the color sensor 51 includes a photodiode PD ₁ (photosensitive element) having a large short-wavelength sensitivity.
And a photodiode PD ₂ (photosensitive element) having a large long-wavelength sensitivity.
And a short-circuit current ratio-wavelength characteristic shown in FIG. Therefore, the color sensor 51 is connected to the master CPU 40 via the signal processing circuit 61 shown in FIG.

The above color sensor signal processing circuit 61
Each photodiode PD ₁ and PD _{2 of the} color sensor 51
The short-circuit current I _{SC1-I SC2} obtained from compressing by the respective logarithmic circuit 62, 62, then, subtracted by the subtraction circuit 63, it is intended to obtain an output voltage V _0. That is,
The following relationship is established with respect to the output voltage V _0.

V ₀ ∝LogI _SC2 −LogI _SC1 = Log (I ₂ / I ₁ ) Here, as shown in FIG. 7, both photodiodes PD
_Since the short-circuit current ratio I _SC2 / I _SC1 of ₁ · PD ₂ is constant regardless of the intensity of incident light, the output voltage V ₀ is also constant. On the other hand, since the short-circuit current ratio I _SC2 / I _SC1 changes depending on the wavelength, the output voltage V ₀ shown in FIG. 9 is obtained with respect to the change in the wavelength.

The photoreceptor type detector 53 is
For example, when the photoconductor detection switch (not shown) is turned on or the photoconductor detection mode is set by an appropriate key operation on an operation panel (not shown), the light emitting element 52 is controlled to be turned on, and the color of the photoconductor 21 is changed. That is, the output of the color sensor 51 corresponding to the type is
0 is input.

That is, as shown in FIG. 10, the photoreceptor 21 has a CG made of pigment and resin
An L layer 72 is formed thereon, and a substantially transparent CTL layer 73 made of a photoconductor and a resin is formed thereon.
2 is determined. For example, as the pigment of the CGL layer 72 in the OPC photoconductor of the laser printer, for example, a phthalocyanine-based material having a light absorption peak near 800 nm as shown in FIG. 11A is used. This is because the wavelength of the semiconductor laser used in the laser printer is around 800 nm. In this case, light around 550 nm having a low absorptance is reflected, so that the photoconductor 21 looks green. Further, as the pigment of the CGL layer 72 in the OPC photoconductor of the analog copying machine,
As shown in FIG. 11B, for example, an azo-based material having a light absorption peak near 500 nm is used. In this case, the photoreceptor 21 appears to be red since the reflectivity of the red wavelength near about 650 nm is high because the photoreceptor 21 has a gentle absorptivity in the entire visible region. Therefore, the master CPU 4
The output voltage V ₀ of the color sensor signal processing circuit 61 input to 0 indicates the type of the photoconductor 21.

The ROM 42 has a program for outputting operation signals and the like to the slave CPU 41 based on signals from various key switches and sensors, a control program for each of the above-mentioned image forming apparatuses, and a color sensor signal shown in FIG. Data and the like indicating the relationship between the output voltage V ₀ of the processing circuit 61 and the wavelength are stored.

In the RAM 64, as shown in Table 1, for example, for each type of photoconductor 21 (A, B, C,...) Used, image forming conditions corresponding to each photoconductor 21, that is, An output value for each image forming device, such as a charging output, a copy lamp voltage, and a developing bias, for performing an appropriate image forming operation by the photoconductor 21 is stored.

The master CPU 40 determines the type of the photosensitive member 21 based on the output voltage V ₀ of the color sensor signal processing circuit 61 and the data shown in FIG.
It is determined whether or not 1 is usable based on a condition described later. If the photoconductor 21 can be used, R
Image forming conditions are set based on data stored in the AM 64. On the other hand, when the photoconductor 21 is unusable, a notification operation of not using the photoconductor is performed to activate the notification unit 65 as a notification unit. The above notification unit 65
Illuminates a service call lamp or a maintenance lamp, for example. In addition, the notification operation may be, for example, an operation that does not start the copy operation even when the copy start button is operated.

The operation of the master CPU 40 for judging whether the photosensitive member 21 is usable or not is as follows.
Is used to determine whether the output value for each image forming device can be adjusted so that an appropriate image forming operation can be performed, and whether the sensitivity characteristic of the photoconductor 21 itself is suitable for the copying machine. It is performed by determining whether or not. To explain the latter, for example, the photoreceptor of a laser printer forms a toner image of 0 or 1 dots of white or black, and therefore generally has a sharp sensitivity. On the other hand, the photoreceptor of the analog copying machine forms a toner image having a gradation ranging from a white background to a halftone and further to a solid black, and thus has a moderate sensitivity. Therefore, it is not appropriate to mount the photoconductor of the laser printer on the analog copying machine because the halftone portion becomes solid black.

In the above configuration, first, the operation of the copying machine when the photoconductor 21 is replaced will be described.

When the photoconductor 21 is replaced and the photoconductor detection switch is turned on, light is emitted from the light emitting element 52 of the photoconductor type detector 53 and is transmitted through the infrared light cut filter 66 to the photoconductor 21. The light is reflected and enters the color sensor 51. At this time, 400 to 1 projected from the light emitting element 52
The light having a wavelength of about 000 nm is
6, the near-infrared light is absorbed,
Only visible light of about 0 nm is transmitted and reflected by the photoconductor 21. As a result, the output voltage V ₀ of the color sensor signal processing circuit 61 is input to the master CPU 40, and the master C
The PU 40 determines the type of the photoconductor 21 from the output voltage V ₀ and the data shown in FIG.
Is available or not. When the photoconductor 21 is usable, each image forming device is controlled so that image forming conditions corresponding to each photoconductor 21 stored in the RAM 64 are set.

Such an operation eliminates the need for a manual operation by a serviceman when the photoconductor 21 is replaced, and can reduce the non-operation time of the copying machine.

On the other hand, if the photosensitive member 21 cannot be used in the discrimination operation of the master CPU 40, the notification unit 65 is operated, and the useless state of the replaced photosensitive member 21 is notified.

Next, the image forming operation of the copying machine will be briefly described. When the copy start button is turned on, the surface of the photoconductor 21 is charged to a predetermined potential by the main charger 22, and the original covered by the original cover 26 is sequentially irradiated from the leading end by the copy lamp 3. . The reflected light from the document is guided to the photoconductor 21 via the optical system 2,
Is exposed, and an electrostatic latent image is formed on the photoconductor 21.

When copying is performed using the automatic document feeder 27 disposed above the copying machine main body 1, the drums 29a and 29b and the like in the document feed path 28 of the automatic document feeder 27. While the original is being conveyed, the original is sequentially irradiated from the leading end by the copy lamp 3 through slits (not shown) provided at two places of the original conveying path 28, and the photosensitive member 21 is exposed in the same manner as described above.

When an electrostatic latent image is formed on the photosensitive member 21,
This electrostatic latent image is developed with toner supplied from the developing device 23 to form a toner image. Thereafter, transfer paper (not shown) is fed to a registration roller 31 from a paper supply unit 30 having a plurality of paper supply cassettes and the like, and is temporarily stopped by the registration roller 31 as necessary. Supplied.

The toner image on the photoconductor 21 is transferred by the transfer unit 24 onto the transfer paper supplied to the photoconductor 21.
Thereafter, the transfer paper is peeled off from the photoreceptor 21 and is conveyed to the fixing unit 33 by the conveyance device 32, where the toner image is fixed on the transfer paper. Is done. On the other hand, in the case of the composite copy and the double-sided copy, the transfer paper discharged from the fixing unit 33 is sent to the paper transport path 35. For example, the sheet is discharged to the intermediate tray 36 after the front and back are turned over by the turning section 37. Then, after a plurality of transfer papers are accumulated in the intermediate tray 36, the transfer papers on the intermediate tray 36 are sequentially fed from the uppermost one by the paper feed roller 38, and
To be copied.

As described above, the light emitting element 52 in the photosensitive member type detector 53 of the above-described electrophotographic apparatus is connected to the photosensitive member 21.
Since the infrared light cut filter 66 is disposed in the optical path of the irradiation light, the reflected light from the photoconductor 21 incident on the color sensor 51 is only light in the visible light region. Therefore, since near-infrared light is incident on the color sensor 51 together with visible light, the wavelength is detected to be longer than the actual wavelength,
A situation in which the color, that is, the type by the photoconductor type detector 53 is not accurately detected does not occur. As a result, the type of the photoconductor 21 can be identified by the master CPU 40, the control of the image forming apparatus corresponding to the type of the photoconductor based on the identification, the notification of improper photoconductor, and the like can be accurately performed. The effect of shortening the non-operation time of the apparatus due to body replacement and preventing toner scattering caused by improper mounting of the photoconductor can be effectively obtained.

In the present embodiment, the infrared light cut filter 66 is disposed in the light path of the irradiation light between the light emitting element 52 and the photosensitive member 21. However, the present invention is not limited to this. And the reflected light from the photoreceptor 21 via the infrared light cut filter 66 may be provided to the photodiodes PD ₁ and PD ₂ .

[0044]

As described above, according to the electrophotographic apparatus of the present invention, the light emitting element for irradiating light to the photoconductor so that the control means can identify the type of the photoconductor incorporated in the main body of the electrophotographic apparatus, An electrophotographic apparatus provided with a photoreceptor type detection unit including a color detection unit having a light-sensitive element that is sensitive to light reflected from the photoreceptor, wherein the photoreceptor type detection unit has a spectral sensitivity characteristic. Based on a light detection signal output by the plurality of different light-sensitive elements in response to the reflected light from the photoconductor, an output voltage having a one-to-one relationship with the wavelength of the reflected light from the photoconductor is output. Configuration.

[0045] As a result, the electrophotographic apparatus of the present invention, sensitive
The photoreceptor type detecting means reads the color of the photoreceptor with the light sensitive element of the color detecting section, and the control means can identify the type of the photoreceptor . Therefore, by controlling the image forming member according to the type of the photoreceptor and detecting improper mounting of the photoreceptor,
This has the effect of effectively reducing the non-operating time of the apparatus due to the exchange of the photoconductor, and preventing toner scattering caused by improper mounting of the photoconductor.

Further, the electrophotographic apparatus of the present invention
As described above, the photosensitive member type detecting means detects whether the photosensitive member
It has an infrared absorption filter that absorbs infrared light from
Configuration.

As a result, the electrophotographic apparatus of the present invention
To the photoreceptor with the infrared absorption filter provided in the photoreceptor type detection means
A light-sensitive element in the color detector to absorb incident infrared light
, The color of the photoreceptor can be accurately read. Therefore,
The control means can identify the type of photoconductor more accurately.
Wear. Therefore, the image forming member according to the type of the photoreceptor
Control and detecting improper photoconductor mounting.
And effectively reduce the downtime of the device due to photoreceptor replacement.
Toner scattering caused by shrinkage or improper mounting of photoconductor
Etc. are effectively prevented.

[0048]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a block diagram of a control system of an electrophotographic apparatus according to an embodiment of the present invention.

FIG. 2 is an overall structural diagram of an electrophotographic apparatus including the control system shown in FIG.

FIG. 3 is an explanatory diagram of an arrangement state of a light emitting element and a color sensor in the photoconductor type detector shown in FIG. 1;

FIG. 4 is a graph showing the relationship between wavelength and light transmittance in an infrared light cut filter.

FIG. 5 is a circuit diagram of the color sensor.

FIG. 6 is a graph showing a relationship between wavelength and relative sensitivity in the above color sensor.

FIG. 7 is a graph showing a relationship between a wavelength and a short-circuit current ratio in the color sensor.

FIG. 8 is a circuit diagram of the color sensor signal processing circuit shown in FIG.

FIG. 9 shows an output voltage V of the color sensor signal processing circuit.
₆ is a graph showing a relationship between ₀ and a wavelength.

FIG. 10 is a sectional view of a main part showing a structure of the photoconductor shown in FIG. 2;

11 is a graph showing the relationship between the wavelength and light absorptivity of each pigment in the CGL layer shown in FIG.

[Explanation of symbols]

21 Photoconductor 40 Master CPU (Control Unit) 42 ROM (Control Unit) 51 Color Sensor (Color Detector) 52 Light Emitting Element 53 Photoconductor Type Detector (Photoconductor Type Detector) 66 Infrared Light Cut Filter (Infrared Absorption) Filter) PD ₁ photodiode (photosensitive element) PD ₂ photodiode (photosensitive element)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-245161 (JP, A) JP-A-58-200240 (JP, A) JP-A-58-224362 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) G03G 15/00 303 G03G 21/00

Claims (2)

(57) [Claims] A light emitting element for irradiating light to the photoreceptor and a light sensitive element for sensing light reflected from the photoreceptor for the control means to identify the type of photoreceptor incorporated in the main body of the electrophotographic apparatus. An electrophotographic apparatus provided with a photoreceptor type detection unit comprising a color detection unit, wherein the photoreceptor type detection unit includes a plurality of light-sensitive elements having different spectral sensitivity characteristics from the photoreceptor. And an output voltage having a one-to-one relationship with the wavelength of the reflected light from the photoreceptor, based on a light detection signal output in response to the reflected light. 2. An electrophotographic apparatus according to claim 1, wherein said photoreceptor type detection means includes an infrared absorption filter for absorbing infrared light from light incident on said photoreceptor.