JPH10240080A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately display the replacing time, on deciding new/old of a unit by providing controlling means capable of performing the generation of image forming material replacement signal indicating that the image forming unit reaches the replacement time when count by counting means becomes to a specified value. SOLUTION: When a power is supplied on the device main body 1B fitted with the drum unit 30, the color developing unit 40(A) and the black developing unit 40(B) there, potential to be input to input terminals IP 31 to IP 310, IP 3 and IP 4 of an interface 81 is severally read. When the respective potential is entirely low level, the every unit is decided as the fresh. Next, when the printing is performed, the print number is severally memorized by a counter A84A or B84B. A CPU 82 on finding that the print number of the counter A84A or B84B severally reached the specified number, performs the display on a display section 85 for requesting replacement of the color developing unit 40(A), or the replacement of the black developing unit 40(B).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus in which an image forming body and a developing unit are unitized and each of them is separately replaceable.

[0002]

2. Description of the Related Art Generally, an image forming apparatus such as a printer used as a terminal device of a computer is a sold-out product. In this case, unlike a leased product,
In principle, the serviceman does not perform a regular inspection, but the user performs the inspection himself and replaces the unit that has reached the replacement time. On the other hand, in the image forming apparatus, a configuration has been developed in which an image forming member requiring replacement is unitized to facilitate replacement of the replacement member. Each of these units has a different life span, and when a new unit is replaced, the claws provided in the unit case may be broken by attachment or the unit may be replaced to detect the new or old unit. The fuse installed in the unit is blown, and the new or old unit is detected by detecting it in the image forming apparatus main body.The replacement time of the old unit is determined by counting the number of printers. Has reached a predetermined value, and a counter for counting the number of prints after replacing the unit has been automatically or manually reset.

The lifespan of a plurality of units is managed independently of each other. For example, it is general that the image forming unit and the developing unit notify the replacement time by detecting or counting each lifespan. Was.

[0004]

In a mechanical method which is conventionally used as a method for detecting unit replacement, such as when a nail is broken at the time of mounting a unit, a processing accuracy for surely breaking the nail is required.

The present invention focuses on the fact that there is a close relationship between the old and new replacement times of the image forming unit and the developing unit. It is an object of the present invention to provide an image forming apparatus which is displayed on a computer and is reliable and easy to manage.

In addition, the life of the image forming unit and the life (or capacity) of the developer in the developing unit generally differ from each other, and in order to always provide a good quality image, it is important to match the characteristics of the two. If the deterioration of the image forming body has been used beyond the guaranteed range, a high quality image may not be obtained even if the developing unit is replaced with a new one. In addition, the deterioration of the image forming body progresses, and often causes the inside of the apparatus to become dirty or defective due to peeling off.

Another object of the present invention is to provide an image forming apparatus in which the replacement time is displayed while maintaining the mutual guarantee range between the image forming unit and the developing unit.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus in which an image forming body and a developing unit are separately replaceable units. Counting means for counting the number of times of discrimination by the new / old discriminating means, and control means for generating an image forming body exchange signal indicating that the image forming body unit is to be replaced when the count by the counting means reaches a predetermined value. This is achieved by an image forming apparatus having:

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An image forming apparatus according to the present invention is an image forming apparatus of a type in which an image forming unit (hereinafter also referred to as a drum unit) and a developing unit (hereinafter also referred to as a developing unit) are separately replaceable. Although all apply, the following three embodiments will be described. Unit life described in the following embodiment (permissible number of prints)
Is merely an example, and the present invention is not limited by the number of prints.

(Embodiment 1) The image forming apparatus according to Embodiment 1 shown in FIG. 1 is a monochrome printer, and shows the configuration thereof. A charging unit 12 for uniformly charging the surface of the photoconductor, an image exposure unit 13 for performing image exposure, a developing unit 14 for performing development, and a transfer for performing transfer and separation are provided on a peripheral portion of the photoconductor drum 11 which is an image forming body. A separating unit 15 and a cleaning unit 18 for cleaning are provided, and the photosensitive drum 11 and the charging unit 12 and the cleaning unit 18 constitute the drum unit 10 and can be attached to and detached from the apparatus main body 1A. . The developing device 14 is also attached to the developing unit 20, and the apparatus main body 1A
It is removable.

In FIG. 1, a photosensitive drum 11 rotating in the direction of an arrow is uniformly charged by a charging unit 12 and then subjected to image exposure by an image exposing unit 13 so that a latent image is formed on the photosensitive drum 11. It is formed. This latent image is developed by the developing device 14 to become a toner image. On the other hand, the recording paper P fed synchronously by the paper feeding means 16 is transferred by the transfer / separation means 15 to the toner image on the recording paper P in a state of being in contact with the photosensitive drum 11, and subsequently, After being separated and transported to the fixing device 17 to be fixed,
It is discharged out of the device. After the transfer, the photosensitive drum 11 is cleaned on the peripheral surface by the cleaning unit 18 to prepare for the next image formation.

In the monochrome printer of this embodiment, the life of the drum unit 10 is 100,000 prints, and the life of the developing unit 20 is 50,000 prints.
When the drum unit 10 and the developing unit 20 are newly mounted and printing is performed, the developing unit 2
When the number of times of replacement of 0 is detected as two times, the replacement of the drum unit 10 is requested.

FIG. 2 is a circuit diagram of a main part of the present embodiment. The drum unit 10 is provided with fuses F ₁₁ and F ₁₂ as counting means for counting the number of times of new / old discrimination, and the developing unit 20 is provided with a fuse F ₂ as new / old discriminating means. By doing so, each of the fuses is connected to a power supply circuit.

By mounting the drum unit 10 on the apparatus main body 1A, the fuses F ₁₁ and F ₁₂ whose one ends are grounded are connected to the power supply V _B (+24 V) in the apparatus main body 1A via the resistors R ₁₁ and R _12. Connected. Fuse F _11, F
The potentials at the ₁₂ connection points are resistors R ₁₃ and R ₁₄ , resistors R ₁₅ ,
Each input terminal via the R ₁₆ interface 71 IP1
1, IP 12 and read by the CPU 72 via the interface 71. On the other hand, the output terminal OP1 interface 71 inverter 73 is connected to the output terminal of the inverter 73 is connected to the power supply V _B through a resistor R _24, R _25. The emitter of the transistor Tr ₁ is connected to the power supply V _B, the base of the transistor Tr ₁ is connected to a connection point between the resistor R ₂₄ and R _25, the collector of the transistor Tr ₁ is the resistance R
₂₆ and the respective switches D ₁₁ and D ₁₁ via the changeover switch SW1.
₁₂ and one of the fuses F ₁₁ and F ₁₂ connected thereto.

[0015] When installed in the developing unit 20 the apparatus body 1A, the fuse F ₂ in a state where one end grounded is connected via a power V _B (+ 24V) to the resistor R ₂₁ in the apparatus main body 1. The potential of the connection point a fuse F ₂ resistance R _22, R ₂₃
Is input to the input terminal IP2 of the interface 71 via the interface 71, and is read by the CPU 72 via the interface 71. The output terminal of the interface 71 is a common output terminal OP1 to which an inverter 73 is connected. The output terminals of the inverter 73 are connected to resistors R ₂₄ and R ₂₄ .
It is connected to a power source V _B through _25. The emitter of the transistor Tr ₁ is connected to the power supply V _B, the resistor R ₂₄ and are connected point to connect the base of the transistor Tr ₁ is the R _25, the collector of the transistor Tr ₁ is resistor R ₂₆ and diode D ₂ It is connected to the fuse F ₂ through.

Next, the operation of this embodiment will be described. When the drum unit 10 and the developing unit 20 are mounted on the apparatus main body 1A and the power switch is turned on, the CPU 7
2, the input terminal IP11 of the interface 71,
Reading of the potential input to IP12 and the input terminal IP2 is performed. If the potentials of the fuses F ₁₁ , F ₁₂ and F ₂ are determined to be low, the drum unit 1
0 and the developing unit 20 are determined to be new, and an initialization process is performed. The initialization process is separately performed by a program stored in a memory connected to the CPU 72. Initialization of the drum unit 10 is performed on the photosensitive drum 1
The operation of charging, exposure, charge elimination and the like is repeated for a predetermined time while rotating 1, and the initialization process of the developing unit 20 is performed by rotating the stirring roller of the developing device 14 for a predetermined time and filling the inside of the developing device. It is possible to make the mixed concentration and charge amount of the toner and the carrier uniform.

When printing is performed, the number of prints is stored in the counter 74. The counter 74 is a non-volatile counter that does not lose its stored contents even after the power is turned off.
The CPU 7 determines that the number of prints on the counter 74 has reached 50,000.
When 2 is detected, a request to replace the developing unit is displayed on the display unit 75. Then, in parallel with this display, the output of the output terminal OP1 rises from a low level to a high level. Thus, the transistor Tr ₁ is turned output of the inverter 73 is changed to the low level, the diode D ₁₁
And the fuse F ₁₁ is blown through the fuse F ₂ is blown through the diode D _2. After blowing of fuses F _11, F ₂ is the potential of the input terminal IP11, IP2 is raised becomes divided by the value of the supply voltage by a resistor. After the fuse is blown, the changeover switch SW1 is switched.

The user has already entered 5 according to the display on the display section 75.
Finished developing ten thousand prints, remove the developing unit 20 which fuses F ₂ is blown from the apparatus main body 1A, the new (not blown) Doing mounting of the developing unit 20 which fuses F ₂ is attached to the counter 74 The number of prints stored in the memory is cleared. The display on the display unit 75 is also cleared. When the developing unit 20 of the new is mounted potential of the fuse F ₂ by the input terminal IP2 of the interface 71 is determined to be in the low level,
When it is determined that the developing unit 20 is new, an initialization process of the developing unit 20 is performed. Note The removed developing unit 20, it is easily determined that a used state by the fuse F ₂ is blown.

When printing is performed after the replacement of the developing unit 20, the number of prints is stored in the counter 74. When the number of prints on the counter 74 reaches 50,000, the CPU 72
Is detected, the output of the output port OP1 rises from a low level to a high level. As a result, the fuse F ₁₂
Fuse F ₂ is fused with. After blowing of fuse F _12, F _2, since the fuse F ₁₁ above is in the fused state, the input terminal of the interface 71 IP11, IP 12, IP2
Becomes high level. The CPU 72 has an input terminal IP11,
When it is detected that IP12 is at the high level and that the input terminal IP2 is at the high level, the display section 75 displays that both the drum unit and the developing unit need to be replaced. The user replaces the drum unit 10 and the developing unit 20 with new ones based on this display. When printing is to be continued without any processing in spite of the request for replacement by the display unit 75, the CPU 72 prints out a predetermined number of prints, for example, 10,000 prints after the request is made. Generate a prohibition signal to prohibit.

By checking the state of the fuse (whether or not it has been blown), the removed drum unit 10 can know how much the drum unit 10 has been used for printing in addition to discriminating between new and old.

In the printing process described above, if the developing unit 20 is sometimes removed from the apparatus main body 1A before a request for replacement is made, the number of prints stored in the counter 74 is cleared. When the developing unit 20 is remounted, the counter 74 stores the number of prints after the reloading on the number of prints previously stored.

In the above description, the embodiment is described in which the fuse is blown when 50,000 prints corresponding to the service life of the developing unit have been printed.
A configuration may be adopted in which the fuse of the unit is forcibly energized and blown when the initialization process is completed or when a new installation is confirmed.

(Embodiment 2) The image forming apparatus according to Embodiment 2 shown in FIG. 3 is a multi-rotation type color printer, and shows the configuration thereof. A charging unit 32 for uniformly charging the surface of the photoreceptor, an image exposing unit 33 for exposing the image, and a developing unit 34 for developing the yellow (Y) color are provided on the periphery of the photoreceptor drum 31 as an image forming body. Y), developing device 34 (M) for developing magenta (M) color, cyan (C)
A developing unit (C) for developing a color, a developing unit (K) for developing a black color, and a transfer / separation unit 3 for transferring / separating
5. Cleaning means 38 for performing cleaning is provided. The photosensitive drum 31, the charging means 32, and the cleaning means 38 constitute a drum unit 30, and
It is detachable from the apparatus main body 1B. Further, the developing devices 34 (Y), 34 (M), 34 (C) constitute a color developing unit 40 (A) integrally, and are detachable from the apparatus main body 1B. Developing unit 34 for developing black
As for (K), the black developing unit 40 (B) is constituted by itself, and is detachable from the apparatus main body 1B.

The color printer shown in FIG. 3 performs image formation in a monochrome mode using only one color of black (K) and in a color mode using four colors of Y, M, C, and K. Image formation in the color mode is performed as follows. In FIG. 3, the photosensitive drum 31 rotating in the direction of the arrow is uniformly charged by the charging unit 32, and then subjected to image exposure corresponding to the Y color by the image exposing unit 33, and the developing unit 34 (Y) applies the Y color. A toner image is formed. The photosensitive drum 31 that continues to rotate is uniformly charged by the charging unit 32, and then subjected to image exposure corresponding to the M color by the image exposure unit 33.
By (M), the M color toner image is formed on the previously formed Y color toner image. By repeating such operations for the C and K colors, the photosensitive drum 31 is
A multi-colored toner image is formed on top of the image.
On the other hand, the recording paper P fed synchronously by the paper supply means 36 is transferred to the multicolor toner image by the transfer / separation means 35 while being in contact with the photosensitive drum 31, and is separated and fixed by the fixing device 37. After being conveyed and fixed, the sheet is discharged out of the apparatus. After the transfer, the photosensitive drum 31 is cleaned on the peripheral surface by the cleaning unit 38 retracted during image formation, and is ready for the next image formation.

In the color printer of this embodiment, the life of the drum unit 30 is 500,000 prints, the life of the black developing unit 40 (B) is 100,000 prints, and the life of the color developing unit 40 (A) is 50,000 prints. I have. Therefore, if an image is formed using only the black developing unit 40 (B), the 5
The replacement of the drum unit 30 is required for each replacement. If an image is formed using only the color developing unit 40 (A), the color developing unit 40 (A)
The replacement of the drum unit 30 is required for the ten replacements. Generally, image formation is performed using both the black developing unit 40 (B) and the color developing unit 40 (A). Therefore, the number of replacements of the black developing unit 40 (B) is m, and the number of replacements of the color developing unit 40 (A) is m. Assuming that the number of replacements is n, the drum unit 30 needs to be replaced when the replacement of (100,000 × m + 50,000 × n) ≧ 450,000 or 500,000 is performed.

FIG. 4 is a circuit diagram of a main part of the present embodiment. The drum unit 30 includes the color developing unit 4
Fuse F _{A1 to} F _A10 corresponding to 0 (A) and fuses F _{B1 to} F _B5 corresponding to black developing unit 40 (B) are provided as counting means for counting the number of times of new / old discrimination. The drum unit 3
Each of the fuses is connected to the power supply circuit by mounting 0 on the apparatus main body 1B. The color developing unit 40
In (A) is the fuse F _A black developing unit 40 (B) are provided as old discriminating means of the respective developing unit is fuse F _B, device each developing unit main body 1
By mounting the fuse on _B , the fuses F _A and FB are connected to the power supply circuit.

By mounting the drum unit 30 in the apparatus main body 1B, the fuses F _{A1 to} F _A10 corresponding to the color developing unit 40 (A) are connected to the power supply V _B in the apparatus main body 1B.
(+24 V) via resistors R _{301 to} R ₃₁₀ .
The potentials at the connection points of the fuses F _{A1 to} F _A10 are respectively the resistances R ₃₁₁ to R ₃₁₁ .
Interface 8 via R ₃₂₀ and resistors R _{321 to} R ₃₃₀
1 are input to the input terminals IP31 to IP310 and are read by the CPU 82 via the interface 81.

On the other hand, the inverter 83A is connected to the output terminal OP3 corresponding to the color of the interface 81, the inverter 83A and the output terminal is connected to a power supply V _B through a resistor R _34, R _35. The emitter of a transistor Tr ₃ is connected to the power supply V _B , and the resistors R ₃₄ and R ₃₅
The base of the transistor Tr ₃ is connected to the connection point with
The collector of the transistor Tr ₃ is connected to one of the fuse F _A1 to F _A10 connected thereto via a resistor R ₃₆ and the changeover switch SW3 and the diode D ₃₁ to D _310.

Similarly, the drum unit 30 is connected to the main body 1 of the apparatus.
B, the black developing unit 40 (B)
Fuse F _B1 corresponding to to F _B5 is connected via a resistor R ₄₀₁ to R ₄₀₅ in the power supply V _B (+ 24V) in the apparatus main body 1B. Fuse F _B1 ~F the potential of the connection point of _B5 are each resistor R
₄₁₁ to R _415, via a resistor R ₄₂₁ to R ₄₂₅ is input to the input terminals IP41~IP45 interface 81 is adapted to be read by the CPU82 through the interface 81. On the other hand, the output terminal OP4 corresponding to monochrome of the interface 81 is connected to the inverter 83B.
There is connected to the output terminal of the inverter 83B is connected to the power supply V _B through a resistor R _44, R _45. The power supply V _B
The emitter of the transistor Tr ₄ is connected to the base of the transistor Tr ₄ is connected to a connection point between the resistor R ₄₄ and R _45, the collector of the transistor Tr ₄ is resistor R ₄₆
And each of the diodes D _{41 to} D ₄₅ via the changeover switch SW4.
And it is connected to one of the fuse F _B1 to F _B5 connected thereto.

[0030] When installed color developing unit 40 (A) to the apparatus main body 1B, the fuse F _A in a state where one end grounded is connected via a resistor R ₃₁ to the power source V _B in the apparatus main body 1 (+ 24V) . The potential at the connection point of the fuse F _A is supplied to the input terminal I of the interface 81 via the resistors R ₃₂ and R _33.
P3 is input to CP via the interface 81.
It is designed to be read by U82. Inverter 83A is connected to the color corresponding output terminals OP3 interfaces 81, further transistors Tr _3, the resistor R
It is connected to the fuse F _A via a diode ₃₆ and a diode D ₃ .

The same is true for the black developing unit. When the black developing unit 40 (B) is mounted on the apparatus main body 1B,
Fuse F _B is the apparatus main body 1B in the end in a state grounded
Is connected to the power supply V _B (+24 V) through a resistor R ₄₁ . The potential at the time of connection of the fuse F _B is input through the resistor R _42, R ₄₃ to the input terminal IP4 interface 81 is adapted to be read by the CPU82 through the interface 81. The output terminal OP4 corresponding to monochrome of the interface 81 has an inverter 83B.
There are connected, it is connected to the fuse F _B through the further resistor R ₄₆ and diode D ₄ and transistor Tr _4.

Next, the operation of this embodiment will be described. When the drum unit 30, the color developing unit 40 (A), and the black developing unit 40 (B) are mounted on the apparatus main body 1B and the power switch is turned on, the interface 81
Of the potentials input to the input terminals IP31 to IP310, IP3, and IP4. When it is determined that all the potentials of the input terminals are at the low level, the drum unit 30, the color developing unit 40 (A), and the black developing unit 40 (B) are determined to be new, and an initialization process is performed. The initialization process is performed by a program stored in a memory connected to the CPU 82. The initialization process of the drum unit 30 is performed by repeating operations such as charging, exposure, and static elimination for a predetermined time while rotating the photosensitive drum 31. The color developing unit 40
(A) and the initialization processing of the black developing unit 40 (B) are performed by rotating the stirring roller of each of the developing devices 34 (Y), 34 (M), 34 (C) or the developing device 34 (K) for a predetermined time. Thus, the mixture concentration and charge amount of the toner and the carrier filled in the developing device are made uniform.

When printing is performed, the number of prints is stored in the counter A84A or the counter B84B. When printing in the monochrome mode, the number of prints is stored in the counter B. When printing in the color mode, the number of prints is stored in both the counter A and the counter B. Each of the counters A and B is a nonvolatile counter which does not lose its stored contents even after the power is turned off. CPU indicates that the number of prints on counter A has reached 50,000
When the detection is made, a display requesting replacement of the color developing unit is displayed on the display unit 85. In parallel with this display, the output of the output terminal OP3 rises from a low level to a high level. Thus, the output of inverter 83A is rendered conductive transistor Tr ₃ changes to the low level, and melt the fuse F _A1 through the diode D _31, the fuse F _A is blown through the diode D _3. Fuse F _A1 ,
After the blowing of F _A , the potentials of the input terminals IP31 and IP3 are raised to a value obtained by dividing the power supply voltage by a resistor. After the fuse is blown, the switch SW3 is switched by one step.

[0034] in accordance with the display user of the display unit 85, remove the color developing unit 40 which fuses F _A is blown (A) from the apparatus main body, a new (not blown) fuses F _A is attached a color developing unit 40
When the mounting of (A) is performed, the number of prints stored in the counter A is cleared. The display on the display unit 85 is also cleared. The removed color developing unit 40
For (A), it is easily determined in the pre condition by a fuse F _A is blown.

Similarly, the number of prints in the counter B is 1
When the CPU 82 detects that the number has reached 100,000, the display unit 85
Is displayed requesting replacement of the black developing unit, and the output of the output terminal OP4 is raised from the low level to the high level. This allows fuses F _B1 and F _B
Is blown. After the fuse is blown, the changeover switch SW4 is switched by one step.

When the user replaces the black developing unit 40 (B) with a new one according to the display on the display unit 85, the number of prints stored in the counter B and the display on the display unit 85 are cleared.

In this embodiment, when the counter A counts 50,000 or the counter B counts 100,000, the CPU 82 checks the blown state of the fuse in the drum unit 30. That is, the number n of terminals at a high level between the input terminals IP31 to IP310 and the number m of terminals at a high level between the input terminals IP41 to IP45 are checked, and (100,000 × m + 50,000 ×
The operation of n) is performed. If the calculation result is less than 450,000, no display is performed. When the calculation result is 450,000 or 500,000, a display requesting replacement of the drum unit 30 is displayed on the display unit 85. The user exchanges a new drum unit based on this display. If the printing is continued without the user replacing the drum unit and the operation result is 550,000 or 600,000 at the time of checking the blown state of the fuse in the drum unit 30, the CPU 82 prohibits the printing. Generate a signal.

The removed drum unit 30 can be checked by checking the number of blown fuses.
In addition to the discrimination between old and new, it is possible to know how much monochrome or color printing has been used.

In the printing process described above, the color developing unit 40 (A) or the black developing unit 40
In the case where the printer is removed from the apparatus main body 1B before the replacement of (B) is requested, the number of prints stored in the counter A or the counter B is retained without clearing, and the color developing unit 40 is not cleared. When (A) or the black developing unit 40 (B) is remounted, the counter A or the counter B stores the number of prints after reloading on the number of prints previously stored.

In the above description, the fuse is blown by the color developing unit 40 (A) or the black developing unit 40.
Although the embodiment is described in which the printing is performed when the number of prints corresponding to the service life of (B) is printed, the fuse of the unit is reset when the initialization process is completed or when a new unit is confirmed to be installed. A configuration may be adopted in which a current is forcibly melted to blow.

(Embodiment 3) The image forming apparatus according to Embodiment 3 shown in FIG. 5 is a one-pass type color printer, and shows the configuration thereof. A charging unit 61Y (M, C, K) for forming images of four colors of Y, M, C, and K (black) and an image exposing unit 62Y (M, C) are formed on the peripheral portion of the photosensitive drum 51 as an image forming body. , K) and the developing device 63Y (M, C,
K) is provided. The photosensitive drum 51 forms a main part of the drum unit 50 and is detachable from the apparatus main body. The developing device 63Y includes a charging unit 61Y.
Together, they constitute a Y developing unit 60Y, which can be attached to and detached from the apparatus main body 1C. Similarly, M, C, K (black)
Also for the M developing unit 60M and the C developing unit 60
C, the black developing unit 60K, and the apparatus main body 1C, respectively.
It is removable.

The charging unit 61Y uniformly charges the image, the image exposing unit 62Y performs image exposure corresponding to the Y color, and the developing unit 63Y rotates the toner image of the Y color on the photosensitive drum 51 which rotates in the arrow direction. Is formed. Similarly, toner images are formed for M, C, and K (black) colors. The image forming apparatus of this embodiment has various image forming modes. In the full-color image forming mode, toner images of Y, M, C, and K (black) are formed on the photosensitive drum 51 in a superimposed manner. Is done. Also, in the black monocolor image forming mode, K
A single color toner image (black) is formed. In the red monocolor image forming mode, Y on the photosensitive drum 51
Is formed so that the toner image and the M toner image completely match and overlap each other. Therefore, in the full car mode, the developing device 63
Y, 63M, 63C and 63K operate in the black monocolor mode, and the developing devices 63Y and 63M operate in the red monocolor mode to form an image.

The toner image formed on the photosensitive drum 51 in this manner is transferred and separated onto the recording paper P fed in synchronism by the paper feeding means 64, and then carries the toner image. After the recording paper P is fixed by the fixing device 66, the recording paper P is discharged out of the apparatus. After the transfer, the photosensitive drum 51 is cleaned on its peripheral surface by the cleaning means 67 in preparation for the next image formation.

In the color printer of this embodiment, the life of the drum unit 50 is 1,000,000 prints, the life of the black developing unit 60K is 200,000 prints,
The developing units 60Y, 60M, and 60C other than K (black) have a life of 100,000 prints. Therefore, if image formation is performed using only the black developing unit 60K, the drum unit 50 needs to be replaced with five replacements of the black developing unit 60K. If the developing unit 6
If image formation is performed using only 0Y, 60M, and 60C, the drum unit 50 needs to be replaced by replacing these developing units ten times. Generally, the number of replacements of the black developing unit 60K is n _K ,
Y, 60M, and n _Y times frequency of replacing 60C, n _M times, 200,000 × n _K +10 ten thousand × when the n _C times _{(n Y + n M + n} C) ≧
When one million developing units are replaced, the drum unit 50 needs to be replaced.

FIG. 6 is a circuit diagram of a main part of this embodiment. The developing units 60Y, 6
Fuses F _{D1 to} F _D10 commonly used for 0M and 60C
F _{E1 to} F _E5 corresponding to and black developing unit 60K
15 fuses are provided, and by mounting the drum unit 50 to the apparatus main body 1C,
Each fuse is connected to the power supply circuit 90. The fuse F _Y to the developing unit 60Y is, the fuse F _M in the developing unit 60M is, the fuse F _M in the developing unit 60M
But fuse F _C to the developing unit 60C is the developing unit 60K have fuse F _K is provided, the fuse of each by mounting each developing unit to the apparatus main body 1C is connected to the power supply circuit 90.

The power supply circuit 90 is a circuit for detecting and blown fuse in the fuse connection, which is configured by a very close to that circuit and the power supply circuit described in FIG. 4, the detailed description is omitted, the fuse F _Y, The potential at the connection point of F _M , F _C , and F _K is determined by the input terminal I of the interface 91, respectively.
It is input to PY, IPM, IPC, and IPK. Similarly, the potential at the connection point between the fuse F _D1 to F _D10 input terminal IPD1
To IPD10 and the potentials at the connection points of the fuses F _{E1 to} F _E5 are input to input terminals IPE1 to IPE5. Inputs of these input terminals are sent to the CPU 9 via the interface 91.
Read by 2. A new drum unit 50 and new developing units 60Y, 60M, 60C,
When the power switch is turned on with the 60K mounted, all the input terminals of the interface 81 go low, and the CPU 92 determines that all units are new and performs initialization processing.

When printing is performed, the developing unit 60
The number of prints is stored in a counter corresponding to the number of prints by Y on the counter Y, the number of printers by 60M on the counter M, and so on. When the CPU 92 detects that the number of prints of any of the counters Y, M, and C has reached 100,000 prints,
The display unit 93 displays a message requesting replacement of a corresponding developing unit, for example, the developing unit 60M. In parallel with this, the output of the output terminal OPM rises from a low level to a high level. This operation will be blown from the fuses F _D1 of the fuse F _M and the drum unit 50 of the developing unit 60M. Similarly, when it is detected that the number of prints of the counter K has reached 200,000 prints, the display unit 93 is requested to replace the developing unit 60K, the output of the output terminal OPK is set to a high level, and the fuse of the developing unit 60K is carry out the blowing of the fuse F _E1 of F _K and the drum unit 50. In the present embodiment, the counter M (Y, C) is set to 10
When the counter K counts 200,000, the CPU
92 checks the blown state of the fuse in the drum unit 50. The number of terminals n _O (= n _Y + n _M + n _C ) at a high level (the fuse is blown) between the input terminals IPD1 to IPD10 and the input terminals IPE1 to IPE
Check the number m _{O of} terminals at the high level (the fuse is blown) during E5, and calculate (200,000 × m _O + 100,000 × n _O ). When the calculation result is 900,000 or 1,000,000, a display requesting replacement of the drum unit 50 is displayed on the display unit. Printing is continued without replacing the drum unit, and the drum unit 50 is replaced.
If the operation result is 1.1 million or 1.2 million at the time of checking the blown state of the fuse in
Reference numeral 92 generates a prohibition signal for prohibiting printing.

Also in the present embodiment, the mode in which the fuse is blown at the time when the number of prints corresponding to the respective service lives of the developing units are printed has been described. Alternatively, a configuration may be adopted in which the fuse of the unit is forcibly energized and blown when a new unit is installed.

[0049]

According to the present invention, the replacement time of the developing unit and the replacement time of the drum unit are complicated.
Regardless of the configuration, the information is displayed extremely appropriately, and the management is simple and clear in the image forming apparatus capable of exchanging units. In particular, when a fuse is used as a discriminating means for discriminating between a new unit and a new unit, it is possible to obtain more information (printing pressure), etc., in addition to being more reliable than a mechanical system in which a nail is broken when a conventional unit is mounted. became.

Further, in the present invention, since the user is notified of the replacement of the image forming unit at the time of replacement of the developing unit, the deteriorated image quality due to excessive use of the image forming unit, in-machine stains, etc. Can be prevented beforehand.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an image forming apparatus according to a first embodiment.

FIG. 2 is a main part circuit diagram of the first embodiment.

FIG. 3 is a configuration diagram of an image forming apparatus according to a second embodiment.

FIG. 4 is a main part circuit diagram of a second embodiment.

FIG. 5 is a configuration diagram of an image forming apparatus according to a third embodiment.

FIG. 6 is a main part circuit diagram of a third embodiment.

[Explanation of symbols]

 10, 30, 50 Drum unit 20, 40, 60 Developing unit 71, 81, 91 Interface 72, 82, 92 CPU 75, 85, 93 Display unit

Claims (10)

[Claims] An image forming apparatus in which an image forming body and a developing device are separately replaceable units. A new / old determining unit for determining whether the developing unit is new or old; Counting means for counting, and control means for generating an image forming body exchange signal indicating that the image forming unit is to be replaced when the count by the counting means has reached a predetermined value. Image forming apparatus. 2. The image forming apparatus according to claim 1, wherein the determination by the determination unit is performed by blowing a fuse. 3. The image forming apparatus according to claim 2, wherein the fuse blowing is a plurality of fuse blowing provided in the image forming unit. 4. The image forming apparatus according to claim 1, wherein the image forming body exchange signal indicates that it is time to replace the image forming body. 5. After the image forming body exchange signal is generated,
5. A printing apparatus according to claim 4, wherein a prohibition signal for prohibiting a printing operation of the image forming apparatus is generated after printing the predetermined number of sheets.
The image forming apparatus as described in the above. 6. The image forming apparatus according to claim 1, wherein the developing unit comprises a monochrome developing unit and a color developing unit, and each of the developing unit is separately replaceable. 7. The image forming apparatus according to claim 6, further comprising a counting circuit for counting the number of replacements of the monochrome developing unit. 8. The image forming apparatus according to claim 6, further comprising a count circuit for counting the number of replacements of the color developing unit. 9. The color developing unit according to claim 6, wherein the color developing unit is a developing unit in which yellow (Y), magenta (M), and cyan (C) developing units are integrated. Image forming device. 10. The color developing unit according to claim 6, wherein the yellow (Y), magenta (M), and cyan (C) developing units are separately provided. An image forming apparatus according to claim 1.