JPH0656519B2 - Development device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an image forming apparatus including a plurality of developing tanks such as a color copying machine, which is provided with a means for determining a developer replacement time of each developing tank. Regarding the device.

(b) Conventional Technology Some image forming apparatuses such as copying machines include a plurality of developing tanks, each developing tank is filled with a different developer, and an image is formed by a plurality of or a single developer. . For example, three developing tanks filled with developers of blue, red, and yellow are provided so that a full-color image or a single-color image using all three colors can be formed. As the developer, for example, a two-component developer is used. A two-component developer has two main components, a toner in which a colorant is mixed in a resin and a carrier made of iron powder or the like. Be charged. The toner adheres to the photoreceptor due to its electrostatic charge to form a development.

When a two-component developer is used, the toner will be replenished while being consumed, so it will not deteriorate, but the carrier will continue to be rubbed with the toner in the developing tank, and will deteriorate with use and the charging property will deteriorate. It may end up. for that reason,
Carriers used for a certain period are replaced.
Usually, the number of times image formation is performed using the same carrier (hereinafter referred to as the number of times of use) is counted, and the number of times the chargeability starts to deteriorate is set as the number of times of exchange, and when the number of times of use reaches the number of times of exchange, the carrier is I am trying to replace it. Actually, it is impossible to exchange only the carrier,
I am replacing the whole developer.

(c) Problems to be Solved by the Invention As described above, in the developing tank having the two-component developer, the developer is replaced when the number of times of use reaches the number of times of replacement. In an image forming apparatus having a plurality of developing tanks, the developing tanks are used singly or in combination, so the number of times of use is different for each developing tank. Then, there is a drawback that it takes time. Further, for example, when the number of exchanges is 10,000, and when the developer in one developing tank is exchanged (the number of times of use is 0), the number of times of use of the other developing tanks is about 9000, mutual development is performed. There is a drawback that the charging times of the toner in each developing tank become unbalanced due to the difference in the number of times the tanks are used, and the balance of toner density becomes poor when an image is formed using both developing tanks. . However, if the developers in all the developing tanks are replaced at the same time when the number of uses of one developing tank reaches the number of replacements, there is a disadvantage that the developers in the developing tanks used less often are wasted.

Therefore, the present invention provides a developing device that includes means for determining whether or not it is necessary to simultaneously replace the developers in all the developing tanks, does not destabilize image quality, and can reduce carrier waste. With the goal.

(d) Means for Solving the Problems The developing device of the present invention is provided with a plurality of developing tanks, each developing tank is filled with a developer, and image formation is performed using all or alternative developing tanks. In the image forming apparatus, the image forming number detecting means for detecting the number of image forming times using the same developing tank is provided for each developing tank, and the image forming number of at least one developing tank among the plurality of developing tanks When the number of times when the quality becomes poor or when the average number of image formation times for each developing tank reaches the number at which the image quality begins to deteriorate, it is necessary to replace the developer in all the developing tanks. And a means for displaying, when the developer replacement necessity determination means determines that the developer in all the developing tanks needs to be replaced, Characterize.

(e) Action If an image is formed by using all or one of the developers in a plurality of developing tanks, the number of times of image formation (the number of times of use) of the developer in each developing tank is the number of times of image formation. It is detected by the detection means. The number of times of use differs depending on the developing tank, but when the number of times of use of at least one developing tank among a plurality of developing tanks becomes extremely large, that is, when an image is formed using the developing tank. When the number of times of use is reached such that the image quality becomes extremely poor, it is judged that the developer needs to be replaced. Also,
When it is desirable to replace the average of multiple developing tanks, that is, the life of each developing tank is collected and the life of each developing tank is determined. When the quality of the formed image starts to deteriorate, it is displayed that the developer in all the developing tanks needs to be replaced.

In this way, a judgment is made to replace all the developing tanks (developer) at the same time, and the fact is displayed at the timing when they may be replaced at the same time. If the developer is replaced at the same time, the balance of the charge amount between the developing tanks will not be deteriorated. Also, if the number of times of use of only one developing tank is extremely high, wait until the number of times of using the developing tank must be replaced (image quality becomes poor). Is determined so that all the developers are replaced. Therefore, the waste of the developer can be minimized.

(f) Embodiment FIG. 4 is a schematic configuration diagram of a copying machine to which the developing device according to the embodiment of the present invention is applied.

A drum-shaped photoconductor 1 is arranged in the center of the copying machine body. A charger 2, a developing tank 3, a transfer drum 4 and the like are arranged around the photoconductor 1. The photoconductor 1 is rotatable in the clockwise direction in the figure, and after being charged by the charger 2, it is exposed to the reflected light from the original at the exposure point P to form a latent image. The document is placed on the document table 5 on the upper surface of the copying machine body. The original is scanned by the light source 61, and its reflected light is reflected by the mirrors 62 to 62.
The photoconductor 1 is irradiated with the exposure point P through the lens 65, the lens 66, and the color separation filter 67. The color separation filter 67 is composed of four filters for blue transmission, red transmission, yellow transmission, and all-color transmission. By interposing one of the filters in the reflected light from the original, the color separation filter 67 Can reproduce colors.

The developing tank 3 is composed of three developing tanks 3 _Y , 3 _M , and 3 _{C. The} difference between the developing tanks is that 3 _Y is yellow toner.
That is, _M has red (magenta) toner and 3 _C has blue (cyan) toner. The developing tank 3 is provided with a developing roller, a stirring roller, a toner concentration sensor, and the like, and is filled with a two-component developer containing toner and carrier as main components (of which toner is about 10%). The developer is agitated by the agitating roller, and the toner and the carrier are triboelectrically charged with opposite polarities. The developing roller adheres the charged toner to the latent image on the photoconductor 1 to form development. The toner concentration sensor detects the toner concentration by, for example, measuring the magnetic permeability of the carrier.

A transfer charger 41, a winding charger 42, a peeling charger 43, a peeling claw 44 and the like are arranged around the transfer drum 4. Paper is supplied from the paper supply unit 7 to the transfer drum 4. The paper is wound around the transfer drum 4 by the winding charger 42, and the toner on the photoconductor 1 is transferred onto the paper by the transfer charger 41. The sheet on which the toner has been transferred is separated from the transfer drum 4 by the separation charger 43 and the separation claw 44, the toner on the surface is fixed, and the sheet is discharged to the sheet discharge unit 8.

A latent image is formed using a filter for transmitting all colors, and development is performed by any one of the developing tanks (one of 3 _Y , 3 _M , and 3 _C ), and the latent image is wound around the transfer drum 4. An image of a single color can be formed by transferring the toner on the photoconductor 1 onto a sheet and ejecting the sheet. Also,
Formation of a latent image using a filter for transmitting a single color → development by a developing tank having toner of the same color as that single color → transfer of toner on the photoconductor 1 onto a sheet wound around a transfer drum 4, By performing the above operation for each color of yellow, red, and blue, and discharging the paper on which the toners of three colors are transferred, a full-color image such as a photograph can be copied.

FIG. 5 is a partial plan view of the operation unit of the copying machine. The operation unit 9 includes display units 91 and 92, a numeric keypad 93, and a clear key 9
4, a print switch 95, a color selection unit 96, etc. are provided. The display portion 91 is a portion where an error message or the like is displayed. The developer replacement lamp 91a, the toner replenishing lamp 91b, the yellow lamp 91c, the red lamp 91d, the blue lamp 91e, the lamp that is turned on when a paper jam occurs, and the waste lamp A lamp and the like that are turned on when the toner is full are provided. The display unit 92 is a numerical value display unit, and displays the number of copies and the error message number. Numeric keypad 9
Reference numeral 3 is a key for inputting the number of copies, clear key 94 is a key for interrupting the copying process, and print switch 95 is a key for starting the copying process. Further, the color selection unit 96 designates one of the three colors when forming an image.

FIG. 3 is a block diagram of a control unit of the copying machine.

The entire control is performed by the CPU 11, and its processing program is stored in the ROM 12 in advance. The RAM 13 is used as a working area when executing this program. The CPU 11 is provided with a developer exchange lamp 91a and a toner replenishment lamp 9 of the operation unit 9 via the I / O 14.
1b, yellow / red / blue lamps 91c to 91e, photoconductor 1, developing roller and agitating roller of developing tank 3, transfer drum 4
Exchange data with etc. CPU 11 is each developing tank 3
_The number of times of use of _Y 3, 3 _M and 3 _C is counted, and RA
Stored in _{M 1,} M 2, _{M 3} of M13. For example, when a red monochromatic image is formed, 1 is added to the red count value.
When a full-color image is formed, one is added to each of the count values of yellow, red, and blue. This count value can be reset by operating the operation switch in the main body of the copying machine. In the present embodiment, the number of times of use is C
Although PU11 counts, a mechanical counter may be provided.

FIG. 1 is a flow chart of the program stored in the ROM 12. In the carrier of this embodiment, the number of exchangeable sheets whose chargeability starts to deteriorate is 10,000, and the carrier can be used up to about 11,000 sheets without deteriorating the image quality. Therefore, at least one usage count is 1
When the number of sheets exceeds 1,000 sheets, or the difference between the number of times of use and the number of exchanges is calculated for each developer, and the total sum becomes 0 or more (the average is 10,000 sheets or more), the developer is replaced. I say it is necessary.

In the figure, M ₁ , M ₂ , and M ₃ are the numbers of times of use of yellow, red, and blue, respectively, and M ₁ ′, M ₂ ′, and M ₃ ′ are yellow and respectively.
Red, the difference between the 10,000 blue number of uses, _{M 4} is _M 1 '~
The total sum of M ₃ ′ is stored. Further, F ₄ is a flag that is set when the number of times of use of at least one developing tank reaches 11,000 times or more, and F ₅ indicates that the number of times of using at least one developing tank is 10,000 sheets or more 11 It is a flag that is set when the number of sheets is less than 1,000.

First, when the power of the main body of the copying machine is turned on, the warm-up is performed at n1 and the memory is initialized. Note that M _{1 to} M ₃ are areas that are not cleared unless a special operation described later is performed. When the warm-up is completed and the operation of the print switch 95 is determined in n2, the copying process is performed in n3. This copying process is performed with a single color or a copying color, and when the copying process is completed, the developing tank used in n4 is counted up.

Set 1 to m at n5. m is M _{1 to} M _{3 of the} memory
And a numerical value representing a permutation of M ₁ ′ to M ₃ ′, n11
→ It will be repeated until it becomes 3 in n12. n6 is the number of times each developing tank has been used and replaced 1
The difference from the number of sheets is calculated and stored in M ₁ ′ to M ₃ ′. If the value exceeds 0, that is, if the number of times of use is less than 10,000, proceed to n11 as it is, and if it is 10,000 or more, proceed to n8 to see if the difference from the replacement number is 1,000 or more. It is determined whether or not (whether the number of times of use is 11,000 or more). Then, it sets the F ₄ in n9 when is 1 thousand or more sheets,
When the number of sheets is less than 1,000, set F ₅ at n10.

If the difference between the number of uses M ₁ , M ₂ , M _{3 of the} developing tanks 3 _Y , 3 _M , 3 _{C and} the number of exchanges (10,000 sheets) is obtained, the set state of F ₄ is determined in n13. As described above, F ₄ is a flag that is set when the number of times of use of at least one developing tank reaches 11,000 sheets or more. If this flag is set, it is necessary to replace the developer. The replacement display signal is output at n14. Then, the process proceeds to n18 to clear the memories M ₁ ′, M ₂ ′ and M ₃ ′ and return to n ₂ .

When F ₄ is in the reset state, the process proceeds to n15 to determine the set state of F ₅ . F ₅ is at least 1 as described above.
This flag is set when the number of uses of one developing tank reaches 10,000 or more and less than 11,000. This flag when is set and stored in M4 by adding the difference between the number of replacements and the number of times of use of each developer tank per stored in M _{1 '~M 3'} proceeds to n16. When this value becomes 0 or more, that is, when the average number of times of use of each developing tank becomes 10,000 or more, it is necessary to replace the developer.
The exchange display signal is output at. Then, at n18, M ₁ ′, M ₂ ′ and M ₃ ′ are cleared and the process returns to n2.

Further, when both F ₄ and F ₅ are in the reset state and when M ₄ exceeds 0, the process proceeds to n18 as it is, and n
18 in to clear the _M 1 '~M _3' Back to n2.

2A and 2B show the display lamps 91a to 91a of the operation unit 9.
It is a flowchart showing the control program of 91e.

When the exchange display signal is output in step n18 of FIG. 1, this is discriminated in n21, and the process proceeds to n22 where the developer exchange lamp 91a and the yellow, red, and blue lamps 91 are outputted.
C, 91d and 91e are turned on. By turning on these lamps, the user can know that the developer needs to be replaced. In this embodiment, yellow, red,
The blue lamps 91c, 91d, and 91e also function as lamps for notifying toner replenishment, and if it is detected that the toner concentrations of yellow, red, and blue are low at n23, n25, and n27, respectively, n24, n25, At 28, the toner supply lamp 91b and the yellow, red, and blue lamps 91c, 91d, and 91e are turned on.

If all the developers are replaced according to the display prompting the replacement of the developers and the switch indicating that the developer has been replaced is operated in the main body of the copying machine, this is determined at n31, and at n32, the developer replacement lamp 91a. And yellow, red and blue lamps 9
1c, 91d, and 91e go out. Further, the flag _F 4, _{F 5} is reset in n33, the memory _M 1 ~M ₃ is cleared. In this way, it is required to replace the developer, and when the replacement is required, the indicator lamp is turned on, and when the replacement is completed, the lamp is turned off.

If toner is replenished when the toner concentration is lowered and the toner replenishment lamp is lit, n34, n36, n3
At 8, the toner concentration sensors of the developing tanks 3 _Y , 3 _M , and 3 _C detect an increase in toner concentration, and n35, n37,
At n39, the toner supply lamp 91b and the yellow, red,
The blue lamps 91c, 91d and 91e are turned off.

FIG. 6 is a flow chart showing another embodiment,
In this example, when at least two developing tanks have been used 10,000 times or more, a replacement display signal is output so as to determine that replacement is required, and the second display signal is used to output the second display signal.
The display lamp is turned on and off as shown in FIGS. In the figure, M _{1 to} M ₃ and M ₁ ′ to M ₃ ′ represent the number of times each developing tank is used and the difference between the number of times each developing tank is used and the number of replacements, as in the above-described embodiment. F _{1 to} F ₃ are flags that are set when the number of uses of each developing tank reaches 10,000 or more.

(g) Effect of the Invention According to the developing device of the present invention, for example, when the number of times of use of at least one developing tank reaches a limit of use slightly larger than the number of times of use, the average number of times of use of all developing tanks is 1 When the number of sheets exceeds 10,000, before the chargeability of the developer deteriorates, and a message prompting you to replace the developer at the right time to compare and replace the developer that has not reached the replacement frequency is displayed. Therefore, it is possible to eliminate variations in chargeability, waste of developer, waste of maintenance, and the like.

[Brief description of drawings]

FIGS. 1 and 2A and 2B are flowcharts of a processing program of a copying machine to which the developing device according to the embodiment of the present invention is applied, FIG. 3 is a block diagram of the copying machine, and FIG. FIG. 5 is a schematic configuration diagram of the copying machine, and FIG. 5 is a plan view of an operating portion of the copying machine. FIG. 6 is a flow chart showing a processing program which is another embodiment. 3 _Y , 3 _M , 3 _C ... Developing tank, 91a ... Developer exchange lamp, 91c ... Yellow lamp, 91d ... Red lamp, 91e ... Blue lamp.

Claims (1)

[Claims] 1. An image forming apparatus having a plurality of developing tanks, each developing tank being filled with a developer, and performing image formation using all or an alternative developing tank, wherein the same developing tank is used. An image forming number detecting means for detecting the number of image forming times is provided for each developing tank, and when the number of image forming times of at least one developing tank among a plurality of developing tanks exceeds the number of times when the image quality becomes poor, or A developer replacement necessity determining means for determining that the developer in all the developing tanks needs to be replaced when the average number of times of image formation in each developing tank reaches the number of times when the image quality starts to deteriorate. A developing device, which is provided with means for displaying a message indicating that the developer in all developing tanks needs to be exchanged by the exchange necessity determining means.