JP2000221779A - Electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic device capable of judging whether the developing device being set or not and the developer being empty in the developing device by output signal of a light receiving sensor dealing with the developing device fixed in a specified position by driving a developing sleeve. SOLUTION: This electrophotographic image forming device is, provided with a photoreceptor 20 on which an electrostatic latent image is formed in accordance with printing data classified by color, plural developing devices 1, 2, 3 and 4, developing device attach/detaching means 13, 14, 15 and 16, transmitting window 5 respectively disposed in position on both side surface facing each other on the developing device, light emitting means 50, a light receiving sensor 51, and driving means 7 rotating the developing sleeve 6. The device is provided with light shielding means moving in synchronism with rotation of the developing sleeve placed between the light emitting means 50 and the light receiving sensor 51, and judging means judging the presence or absence of the developing device and empty of the developer in the developing device by the output signal of the light receiving sensor 51 with regard to the developing device fixed in the specified position by driving the developing sleeve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus using a one-component developer, and more particularly, to an electrophotographic apparatus for detecting a set of a developing apparatus using a one-component developer and detecting empty developer.

[0002]

2. Description of the Related Art Conventionally, various means have been used for detecting an empty developer, and these means employ a method of mechanically detecting a driving load torque of an agitator for supplying and stirring toner in a developing device. One is disclosed in Japanese Patent Publication No. 62-502. Japanese Patent Laid-Open No. 6-19314 discloses an arrangement in which a toner presence / absence detecting means for detecting the presence / absence of toner is disposed near the last agitator closest to the developing sleeve of the agitator for stirring the toner. Further, Japanese Patent Application Laid-Open No. Hei 10-186822 discloses an apparatus in which a time interval during which light passing through a toner cartridge is transmitted is measured to continuously detect the remaining amount of toner.

[0003] Using a similar light emitting sensor and light receiving sensor,
The one that detects the presence or absence of the toner filled in the developing device and turns off the power of the light emitting sensor and light receiving sensor when it is unnecessary,
It is disclosed in JP-A-10-133465. On the other hand, as for the detection of the presence / absence of toner in a conventional developing device, a method of detecting the presence / absence of an output of an optical sensor at a predetermined rotational position in a rotating developing device is disclosed in Japanese Patent Laid-Open No. 8-314230. It is disclosed in the gazette.

[0004]

However, the conventional methods for detecting the empty state of the developing device, that is, the presence / absence of the developer, and the methods for detecting the presence / absence of the setting of the developing device for detecting whether or not the developing device has been set are described below. Although they were individually known as independent technologies, a configuration capable of detecting both of them using the same sensor and without adding a special component has not been known so far.
For cost reduction, there is a demand for an electrophotographic apparatus capable of simultaneously detecting emptyness of a developing device and set detection of a developing device. Accordingly, the present invention has been made in view of the above-described problems, and an object of the present invention is to provide an electrophotographic apparatus capable of simultaneously performing empty detection of a developing device and detection of a set of a developing device for miniaturization and cost reduction. It is to be.

More specifically, an object of the present invention is to provide an electrophotographic apparatus having a plurality of developing devices and moving and fixing only necessary developing devices to a developing position. An object of the present invention is to provide an electrophotographic apparatus capable of detecting the presence or absence of a developing device using a sensor for detecting whether an agent (or toner) is empty. Further, an object of claim 1 of the present invention is to detect the developer empty using light transmitted through the developing device, so that the moving amount of the developing device is particularly small and the developing device is separated from the developing position. It is an object of the present invention to provide an electrophotographic apparatus capable of reliably detecting whether a developing device is set even if transmitted light is generated in such a case. Further, the object of the invention of claim 1 of the present invention is to realize a small-sized, low-cost and low-cost apparatus by comprising a set of detecting means.
An object of the present invention is to provide a highly reliable electrophotographic apparatus. An object of an electrophotographic apparatus according to a second aspect of the present invention is to provide an electrophotographic apparatus capable of performing empty detection of developer and detection of presence / absence of setting of a developing apparatus by the same detecting means. An object of the electrophotographic apparatus according to claim 3 of the present invention is to further reduce the size of the electrophotographic developing apparatus by using the light shielding means as an indispensable gear as a developing apparatus, and to realize a small and low-cost electrophotographic apparatus. To provide. An object of an electrophotographic apparatus according to a fourth aspect of the present invention is to further reduce the size of an electrophotographic apparatus by using a light shielding means as an indispensable agitator as a developing apparatus, thereby achieving a small and low-cost electrophotographic apparatus. To provide. An object of an electrophotographic apparatus according to a fifth aspect of the present invention is to provide a configuration in which a detection circuit includes an LED and a phototransistor, and an output of the phototransistor is connected to control means such as a microcomputer via a comparator. , A detection means that can reliably detect fine fluctuations in the developer and is resistant to external noise.
It is to provide at low cost and high reliability. An object of an electrophotographic apparatus according to a sixth aspect of the present invention is to use a configuration in which a detection circuit includes an LED and a phototransistor and an output of the phototransistor is connected to an A / D converter of a microcomputer. It is an object of the present invention to provide a low-cost and high-reliability electrophotographic apparatus capable of arbitrarily setting a determination level for a power level and detecting a remaining amount level of a developer.

[0006]

In order to solve the above-mentioned problems, an electrophotographic apparatus according to claim 1, wherein an electrostatic latent image is formed according to color-coded print data. A plurality of detachable developing devices for developing the electrostatic latent image with toner, and fixing the developing device for developing the corresponding color when developing the corresponding color at a position close to the photoconductor A developing device separating / contacting means for separating the developing device after completion of development, first and second transmission windows provided at opposing positions on both side surfaces of each of the developing devices, and each of the developing devices mounted thereon; A light emitting means provided at a location that coincides with the position of the first transmission window when has reached the development position;
An electrophotographic apparatus comprising: a light receiving sensor provided at a position corresponding to a position of a second transmission window facing the first transmission window; and driving means for rotating a developing sleeve of the developing device. Light-shielding means disposed between the light-receiving sensor and the light-receiving sensor, the light-shielding means moving in synchronization with the rotation of the developing sleeve, and the output of the light-receiving sensor corresponding to the developing device fixed to a predetermined position by driving the developing sleeve. An electrophotographic apparatus comprising: a determination unit configured to determine whether the developing device is set and whether the developer in the developing device is empty based on a signal. According to a second aspect of the present invention, in the electrophotographic apparatus according to the first aspect, the developing device separating / contacting means is fixed to a predetermined position for bringing the developing device close to the photoconductor, and A set presence / absence determination means for determining that the development device has not been set when the light receiving sensor at that time always outputs the first level output value by driving the sleeve; The judging means is an electrophotographic developing device for judging that the developer is empty by the light receiving sensor outputting an output value of a second output level for a first predetermined time.
According to a third aspect of the present invention, in the electrophotographic apparatus according to the first aspect, the light blocking unit rotates in synchronization with the developing sleeve and is driven in synchronization with the rotation of the developing sleeve. A gear, wherein a rotating surface of the gear is provided at a position facing a transmission window of the developing device, wherein the gear has at least one or more transmission windows for transmitting light; Is an electrophotographic apparatus that periodically blocks light passing through the developing sleeve in synchronization with the rotation of the developing sleeve. According to a fourth aspect of the present invention, in the electrophotographic apparatus according to the first aspect, the light-shielding means is rotated in synchronization with the developing sleeve, and is provided with an agitator for moving the developer in the developing device. An electrophotographic apparatus, wherein the transmission window is provided within a rotation radius of the agitator. The electrophotographic apparatus according to claim 5 is the electrophotographic apparatus according to claim 2, wherein the light emitting means is an LED, the light receiving sensor is a phototransistor, and the phototransistor has a collector via a resistor. Or the emitter is grounded and the collector is connected to the comparison means, or the collector is connected to the power supply, the emitter is grounded via a resistor, and the emitter is connected to the comparison means. And
An electrophotographic apparatus that inputs an output of the comparing unit to a control unit and determines the presence or absence of light reception based on an output level of the collector or the emitter. The electrophotographic apparatus according to claim 6 is the electrophotographic apparatus according to claim 2, wherein the light emitting means is an LED, the light receiving sensor is a phototransistor, and the phototransistor has a collector connected through a resistor. Or the emitter is grounded through a resistor, or the collector is connected to a power supply,
An electrophotographic apparatus in which the emitter is grounded via a resistor, the collector or the emitter is connected to an A / D conversion input of a control means, and the presence or absence of light reception is determined according to the value of the A / D conversion input.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A color laser printer according to the present embodiment will be described with reference to FIG. The color laser printer of the present invention includes a photoreceptor 20, a scorotron charger 21, a laser 19 as an exposure unit, developing units 1, 2, 3, and 4 corresponding to each color, a transfer belt 22,
The image forming apparatus includes a transfer roller 23, a paper transport roller 26, a paper transfer roller 25, and a fixing device 30. The image forming process will be described. The photoconductor 20 is uniformly charged by the scorotron charger 21 and an electrostatic latent image of a first color is drawn thereon by the laser 19. The image is developed by the first developing device 1 corresponding to the color. The developed image is transferred to the transfer belt 22 by the transfer roller 23. Next, the photoconductor 20 is uniformly charged, an electrostatic latent image of the second color is written by the laser 19, and is developed by the second developing device 2. The developed image is transferred onto the transfer belt 22 in a superimposed manner. Similarly, when the image is superimposed on the transfer belt up to the fourth color, the image is transferred to an image receiving member such as paper or a plastic film sent from the paper conveyance roller 26.
The image on the transfer belt 26 is transferred to the image receiving member by the paper transfer roller 25, and is fixed by the fixing device 30 to complete the printing.

When a color printer is used only in monochrome, control is performed such that only a developing device containing a black developer is used. Also, when only a specific color is used, control is performed so that only necessary developing units are used without using all the developing units of four colors. A developing device that develops an electrostatic latent image corresponding to a predetermined color,
It is shown that the cams 13 to 16 press the photosensitive member 20 and the other developing devices are separated from the photosensitive member 20 without being pressed. In the case of FIG. 1, the first cam 1
3 is a position for pressing the developing device, and the first developing device 1
Is fixed at a position adjacent to the photoconductor 20.

The first developing device 1 fixed at the developing position includes:
When the first developing clutch DC1 is connected, the gear 7 attached to the shaft of the developing sleeve 6 is driven by the developing motor DM, and the developing sleeve 6 is simultaneously rotated. At the same time, the transmission gears 8 and 11 rotate the gears 10 and 12 attached to the shaft 42 of the agitator 44. The gear 9 is driven by the gear 10 and drives the agitator 44 to rotate. The windows 5 are provided on both opposing side surfaces of the developing units 1, 2, 3, and 4, respectively, and serve as transmission windows that allow light blocked by a transparent material to pass therethrough. The transmission window is provided close to the bottom surface of the developing device, and is configured to be able to see through when the developer runs out. The configuration of the agitator 44 will be described later in more detail. Each developing sleeve is connected to a high-voltage power supply DF (not shown), and is controlled so that a proper developing condition is obtained by applying a bias voltage. The high-voltage power supply C is connected to the wire of the scorotron charger 21 and the high-frequency power supply G is connected to the grid, and are controlled so that optimum development conditions are obtained.

The transfer roller 23 is connected to a high-voltage power supply T1 (not shown), and is controlled so that the developer (toner) on the photoconductor moves to the transfer belt 22 appropriately. The transfer belt 22 is configured to collect the developer remaining on the surface by the cleaning roller 24 when the image transfer to the paper is completed. The cleaning roller 24 is connected to a high-voltage power supply CL (not shown), and a bias voltage is applied thereto. FIG. 2 shows the agitator 44 described above. The agitator 44 has a holed mylar sheet 4
3 is bonded to a shaft 42, and both ends thereof are reinforced by hard plate members 40 and 41. The agitator 44 has a function of moving the developer by rotating the shaft. FIG.
FIG. 3 is a diagram showing an outline of the vicinity of the transmission window 5 and its peripheral portion of the developing device provided with the agitator 44 shown in FIG. A transmission window 5 is provided at a position facing the both side plates of the developing device, and the transmission window 5 is closed by a transparent member. Further, the transmission window 5 is disposed within the radius of rotation of the agitator 44. In the present embodiment, the gear 10 for driving the agitator 44 is also configured such that the transmission window is disposed within the radius of rotation.

FIG. 4 is a view showing the gear 10 described above. The gear 10 has an outer peripheral portion on which gear teeth are formed, and eight ribs extending from the outer peripheral portion toward the radially inner center portion, and the interval between the ribs is increased toward the outer peripheral portion. It is configured to form eight voids. Regarding another configuration of the agitator 44 main body, see Japanese Patent Application Laid-Open No.
Since it has the same functional role as that described in detail in Japanese Patent Application Laid-Open No. 4-4, no further description will be given in the present invention. FIG. 3 shows that the developing device is fixed at the developing position, and the developing device is provided with the light emitting means 50 and the light receiving sensor 51 at positions corresponding to the transmission windows of the side plates of the printer main body. When the cams 13 to 16 rotate and the developing device is released from the developing position, the light emitting unit 50 and the light receiving sensor 51 are shifted from the transmission window. However, since the developing position and the opened position only slightly move, light is slightly leaked from the transmission window even when the developing position is opened.

FIG. 5 is a diagram showing a light receiving sensor 51 and an example of a circuit at the subsequent stage. The light receiving sensor 51 has four phototransistors PT1, PT2, PT3, and PT4 attached to a printed circuit board. A first developing device and PT1,
The second developing device corresponds to PT2, the third developing device corresponds to PT3, and the fourth developing device corresponds to PT4. The light receiving sensor 51 is connected to the control board by a harness. On the control board, the emitter of PT1 is grounded, the collector is connected to a 5V power supply via a diode D10 and a resistor R10, and a resistor R10 is connected to an inverting input terminal (pin 8) of a comparator IC10 as comparison means.
Connected through. A reference voltage obtained by dividing a 5V power supply by a resistor R13 and a resistor R12 is input to a non-inverting input (pin 9) of the IC 10. By applying a bias other than 0 V to the non-inverting input in this way, the device of the present invention can be stabilized against external noise, and the reference level can be adjusted by the resistors R13 and R13.
By changing 12, there is an effect that it can be set arbitrarily. PT1 has a high resistance when not receiving light, and its resistance value decreases as the light amount increases. When the voltage obtained by dividing the voltage obtained by subtracting the voltage drop of D10 from the 5V power supply by the resistance value of the resistor R10 connected to the collector of PT1 and the resistance value of PT1 becomes smaller than the above-described reference voltage, that is, the photodiode emits light. Corresponding to the case where light is received, the collector voltage of the photodiode and the above-described reference voltage are compared by a comparator used as a comparing means. The output (pin 14) of the IC 10, which is a comparator, is L (low level) when no light is received, and H (high) when the phototransistor receives light and the collector potential becomes lower than the reference voltage. Level). The output of IC10 is connected to the input port of control means IC1 such as a microcomputer. The capacitor C10 is for noise absorption, and the resistor R14 is for pull-up.

In another embodiment of the present invention, the output of the photodiode is connected to the AD conversion input of IC1 without going through a comparator. PT2, PT3, PT
4 has the same configuration as that of the first embodiment described above, and is connected to each input port of the IC 1. FIG. 6 is a diagram showing the light emitting means 50 and its related circuits. In the circuit shown in FIG. 6, four LEDs
LD1, LD2, LD3, LD4 and two resistors R1, R
2 and a capacitor C1 are mounted on a printed circuit board. The light emitting means 50 is connected to a 5V power supply by a harness. Two sets of LEDs are connected in series. The anode side is connected to a 5V power supply via current limiting resistors R1 and R2, and the cathode side is grounded to ground.

FIGS. 7, 8 and 9 show the collector voltage waveforms when the phototransistor is connected to a 5V power supply by a resistor. FIG. 7 shows a collector voltage output waveform of the phototransistor when the light receiving sensor 51 does not receive light. When the phototransistor does not receive light, the collector voltage is kept high. "0" indicates a ground potential, which is lower than the above-described reference voltage and indicates that external noise is superimposed. This output state may be the case where the developing device is not at the developing position and the positions of the transmission window 5, the light emitting means 50 and the light receiving sensor 51 are completely displaced, or even if the developing device is located at the developing position, The case where the window is closed can be mentioned.

FIG. 8 shows a collector voltage output waveform when the light receiving sensor 51 receives transmitted light. When the phototransistor does not receive light, the collector potential is kept high. When light is received, the resistance of the phototransistor decreases, so that the collector potential decreases. The case where the collector potential output waveform shown in FIG. 8 is obtained is a case where the developing device is arranged at the developing position, the developer is consumed to some extent, and the transmission window is not completely covered. Rotate to reinforce plate members 40, 41
And the case where the light is shielded by the ribs with the rotation of the gear 10 provided with the gap by the ribs.

FIG. 9 shows a collector voltage output waveform of the light receiving sensor 51 under another condition. The output shown in FIG. 9 occurs when the developing device is not set at all, and the output level of the phototransistor is L level and almost constant while the phototransistor is constantly receiving light. Although not shown in these waveforms, noise as shown in FIG. 8 is superimposed. When these noises are connected to the comparator of FIG.
This results in a shaped waveform of H ”or“ L. ”By doing so, the problem of external noise received by the light emitting means 50 and the light receiving sensor 51 can be reduced, and a configuration which is reliable against noise can be obtained. In the second embodiment, the output of the light receiving sensor 51 is directly connected to the AD conversion input of the microcomputer without using a comparator in order to finely detect the remaining amount of the developer by using the level change of the light receiving sensor 51. Is what you do.

FIG. 10 is a block diagram showing an outline of an electric device used in the present invention. The electric device of the present invention
It comprises a main control unit MCU consisting of peripheral circuits centered on the microcomputer IC1. The MCU includes a photoconductor 20, a belt motor BM for driving the transfer belt 22, a developing motor DM for driving the developing devices 1, 2, 3, and 4, a paper transport roller 26, and a fixing device 30.
, And developing clutches DC1, DC2, DC3, DC for intermittently driving the sleeve of the developing device.
And a contact / separation clutch CC for bringing the developing device into and out of the developing position.
12, CC34, a high-voltage power supply, a light emitting unit LD for detecting the presence or absence of a developing device and empty developer, the light receiving sensors PT1, PT2, PT3, PT4, and heater control. Although not shown, the MCU also controls laser writing control and other functions. The temperature of the heater (HEAT) of the fixing roller is detected by a thermistor (TH) and controlled to a predetermined temperature by heater control.

FIG. 11 shows a subroutine (CHE) used for a method of judging the presence or absence of the setting of the developing device and the detection of empty developer.
5 shows a flowchart of (CK & TEND). First, the method of the present invention starts at step 100 and proceeds to step 10
The development motor DM is started by the "development M: ON" of 1. Next, in step 102, "first developer contact / separation: ON", the cam 13 is rotated by the contact / separation clutch CC12 so that the first developing device moves to the development position. At the same time, the developing clutch is turned on to rotate the sleeve. Then step 10
In 3, the output of the photodiode PT1 is determined by monitoring the light receiving sensor 51 for a certain period of time.
Is determined whether or not the output is at the output collector potential high level “PT1 = H”. As described above, in the present invention, the output voltage of the light receiving sensor 51 outputs an L level when the phototransistor continuously receives light. Therefore, in such a case, the program
It is determined that “PT1 = H” is not satisfied and the developing device is not mounted, the process proceeds to step 104, a flag of “no first developing device set” is set in step 104, and the “first developing device” of step 109 is set. The process proceeds to "contact / separation: OFF" to separate the first developing device from the developing position. If a state where no light is received for a certain time interval is detected separately, in this case,
The state of “PT1 = H” is observed at least for a predetermined time interval.
, It is determined that the first developing device is set. In step 105, a flag of "the first developing device development set is present" is set. In step 106, whether the photodiode PT1 is at L (low level) or not is determined. Judge. In step 106, the photodiode PT1 sets “PT1 =
L is determined, and if the light receiving sensor 51 receives light for the first predetermined time and the collector output voltage becomes L level, the developer of the first developing device is empty. Is determined, the process proceeds to step 108, and a flag of "first developer: empty" is set. The light receiving sensor 5
If 1) receives light for the second predetermined time and outputs a predetermined voltage, in step 108, it is determined that the developer of the first developing device is not empty yet, and in step 10
Proceeding to 7, normal operation is performed. It is preferable that the above-mentioned first time is set longer than the above-mentioned second time according to the amount of remaining toner. It is known in Japanese Patent Application Laid-Open No. 10-186822 and the like that when the remaining amount of toner is optically detected, the pulse width changes according to the remaining amount and the voltage level of the detection signal changes. Therefore, although the description in the present invention is omitted, it is preferable that the first predetermined time and the second predetermined time described above correspond to the amount of the developer in the developing device. Then step 10
In 9, the developing clutch is turned off by “first developing device contact / separation: OFF” to stop driving the sleeve of the first developing device, and at the same time, the contact / separation clutch is operated to set the cam to the position where the developing device is released. The above operation is similarly performed for the second, third, and fourth developing devices, and the process exits from the subroutine in step 500 of FIG.

When the signal is directly input to the AD converter without using the comparator, the voltage level for determining whether or not light has been received can be arbitrarily set. It is done. Taking a copying machine as another embodiment, the copying machine has a configuration in which a scanner for reading a document is added to a printer, and it is clear that the present invention can be applied as it is. Although not particularly shown in the present invention, even if the collector of the phototransistor is connected to a power supply, grounded through the resistance of the emitter, and controlled using the output voltage of the emitter, the transmission of the transmitted light can be controlled. Although the logic depending on the presence / absence is inverted, it is clear that other operations and configurations of the present invention can be applied as they are.

[0020]

As described above, in the electrophotographic apparatus according to the first aspect, a member for periodically shielding light between the light emitting means and the light receiving means for detecting the presence or absence of the developer when the developing apparatus is driven. Is provided, it is possible to reliably detect the presence or absence of the setting of the developing device with a simple configuration and at low cost. In the electrophotographic apparatus according to the second aspect, even if the developer is empty, if the developing device is set, the light is periodically shielded without fail, so that the presence or absence of the setting of the developing device can be reliably detected. Further, since the state of the light receiving sensor is not detected when the developing device is separated and the light emitting unit is separated from the transmission window, the separation amount can be reduced, and the size of the device can be reduced. In the electrophotographic apparatus according to the third aspect, the light-shielding means is also used as an indispensable gear as a developing device, so that the size of the electrophotographic apparatus can be reduced.
It can be provided at low cost. In the electrophotographic apparatus according to the fourth aspect, since the light shielding means is also used as an agitator which is indispensable as a developing device, the size of the electrophotographic apparatus can be reduced and the electrophotographic apparatus can be provided at low cost. In the electrophotographic apparatus according to claim 5, the detection circuit comprises:
By connecting the LED, the phototransistor, and the output of the phototransistor to a microcomputer via a comparator, it is possible to reliably detect fine fluctuations in the developer and to use a detection means that is resistant to external noise. It can be provided at high cost and high reliability. Claim 6
In the electrophotographic apparatus described in (1), since the detection circuit is configured to connect the LED, the phototransistor, and the output of the phototransistor to the A / D converter of the microcomputer, the determination level for the output level of the phototransistor can be arbitrarily set. , The judgment level can be changed according to the change in the characteristics of the circuit over time or the change in the transmittance of the transmission window, and the change in the remaining amount of the developer can be detected using the change in the level, thereby reducing costs and increasing reliability. It is possible to provide an electrophotographic apparatus.

[Brief description of the drawings]

FIG. 1 is a diagram showing a color laser printer of the present invention.

FIG. 2 is a diagram showing an agitator used in the present invention.

FIG. 3 is a diagram showing the vicinity of a transmission window and its peripheral portion of the developing device of the present invention.

FIG. 4 is a diagram showing an agitator driving gear used in the present invention.

FIG. 5 is a diagram showing a light receiving sensor of the present invention and a circuit example thereof.

FIG. 6 is a diagram showing a light emitting means of the present invention and a circuit configuration thereof.

FIG. 7 is a diagram showing a voltage waveform at the collector of the phototransistor of the present invention.

FIG. 8 is a diagram showing a voltage waveform at the collector of the phototransistor of the present invention.

FIG. 9 is a diagram showing a voltage waveform at the collector of the phototransistor of the present invention.

FIG. 10 is a block diagram showing an outline of an electric device used in the present invention.

FIG. 11 is a flowchart illustrating a subroutine used to determine the presence / absence of a developing device set and developer empty detection according to the present invention.

[Explanation of symbols]

 1, 2, 3, 4 Developing device 5 Transmission window 6 Developing sleeve 8 Gear 9 Gear 10 Gear 11 Gear 12 Gear 13-16 Cam 20 Photoconductor 21 Scorotron charger 22 Transfer belt 23 Transfer roller 24 Cleaning roller 25 Paper transfer roller 26 Paper transport roller 30 Fixer 40, 41 Plate 42 Shaft 43 Mylar sheet 44 Agitator 50 Light emitting means

Claims (6)

[Claims] 1. A photoreceptor on which an electrostatic latent image is formed in accordance with color-coded print data, a plurality of detachable developing devices for developing the electrostatic latent image with toner, and developing a corresponding color A developing device for developing the color at the time of fixing the developing device at a position close to the photoconductor and separating the developing device after the development is completed; and a developing device separating and contacting means provided at opposite positions on both side surfaces of the developing device. First and second transmission windows, and a light-emitting means provided at a location corresponding to the position of the first transmission window when each of the developing devices is mounted and the developing device reaches a developing position; An electrophotographic apparatus comprising: a light receiving sensor provided at a position corresponding to a position of the second transmission window facing a first transmission window; and driving means for rotating a developing sleeve of the developing device. Between the light receiving sensor and A light-shielding unit that is provided and moves in synchronization with the rotation of the developing sleeve; and whether or not the developing device is set based on an output signal of the light receiving sensor corresponding to the developing device that drives the developing sleeve and is fixed at a predetermined position. An electrophotographic apparatus comprising: a determination unit configured to determine whether the developer in the developing device is empty. 2. The electrophotographic apparatus according to claim 1, wherein the developing device separating / contacting means is fixed at a predetermined position for bringing the developing device close to the photoconductor, and driving the developing sleeve at that time. When the light receiving sensor constantly outputs the output value of the first level, the developing device includes a setting presence / absence determination unit that determines that the development device is not set. Light receiving sensor is second
An electrophotographic apparatus characterized in that it is determined that the developer is empty by outputting an output value at the output level of the first predetermined time. 3. The electrophotographic apparatus according to claim 1, wherein the light shielding unit is a gear that rotates in synchronization with the developing sleeve and is driven in synchronization with the rotation of the developing sleeve. Is provided at a position facing the transmission window of the developing device, and the gear has at least one or more transmission windows for transmitting light, and traverses the transmission window of the developing device. An electrophotographic apparatus, wherein light generated is periodically blocked in synchronization with rotation of the developing sleeve. 4. The electrophotographic apparatus according to claim 1, wherein the light blocking means is provided on an agitator which rotates in synchronization with the developing sleeve and moves the developer in the developing device. An electrophotographic apparatus, wherein the transmission window is provided within a turning radius of an agitator. 5. The electrophotographic apparatus according to claim 2, wherein the light emitting means is an LED, the light receiving sensor is a phototransistor, and the collector of the phototransistor is connected to a power supply via a resistor, The emitter is grounded and the collector is connected to the comparing means, or the collector is connected to a power supply, the emitter is grounded via a resistor, and the emitter is connected to the comparing means; An electrophotographic apparatus characterized in that the output of (1) is input to a control means, and the presence or absence of light reception is determined based on the output level of the collector or the emitter. 6. The electrophotographic apparatus according to claim 2, wherein the light emitting means is an LED, the light receiving sensor is a phototransistor, and the collector of the phototransistor is connected to a power supply via a resistor, The emitter is grounded via a resistor, or the collector is connected to a power supply, the emitter is grounded via a resistor, and the collector or the emitter is connected to an AD conversion input of a control means; An electrophotographic apparatus for determining whether light is received according to a value of a conversion input.