JP2003208063A - Image forming apparatus and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus and a process cartridge which correctly inform a user that a developing unit comes to the end of its life, before image quality degradation regardless of the presence or absence of toner in the developing unit. <P>SOLUTION: The image forming apparatus has a photoreceptor drum 1, an exposure unit 5 which irradiates the photoreceptor drum 1 with modulated light according to input image information, and the developing unit 10 which contacts the photoreceptor drum 1 carrying an electrostatic latent image formed by the exposure unit 5 and renders the electrostatic latent image visible with developer transported by a developer transportation member. In the image forming apparatus, pieces of information about the temperature of the developer transportation member and the operating times of the developer transportation member are integrated and the integration results are stored. Based upon the stored results, a user is informed of the replacement time of the developing unit 10. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying machine and an electrophotographic printer, and a process cartridge.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic system, a photoconductive substance is used to form an electric latent image on a photoconductor by various methods, and then the latent image is developed with toner to form a visible image, which is required. The toner image is transferred onto a transfer material such as paper in accordance with the requirements, and then fixed by heat or pressure to obtain a copy.

At the present time, however, it is essential to develop a method for forming a thin layer of a toner and an apparatus therefor, which requires improvement in the resolution and definition of an image, and several measures have been proposed for this. ing.

In recent years, a "non-magnetic one-component DC contact developing system" has been proposed in which a semi-conductive developing roller or a developing roller having a dielectric layer formed on the surface thereof is used to contact the surface layer of a photosensitive member for development. .

FIG. 5 shows an image forming apparatus using a non-magnetic one-component DC contact developing system. In this system, the photoconductor 21 and the developing roller 81 are in contact with each other and rotate in the directions of arrows A and B, respectively. The photoconductor 21 is charged by the charging roller 2, and a latent image is formed on the photoconductor 21 by the laser light from the exposure unit 5. Then, the latent image is visualized by the developing device 80. Then, the toner image on the photoconductor 21 developed by the toner 84 is transferred to the transfer material 9 by the transfer roller 6 and fixed by the fixing device 7. On the other hand, the toner 84 remaining on the photoconductor 21 without being transferred
Are stripped off by the cleaning blade 3 and housed in the cleaning container 4.

The developing device 80 includes an elastic blade 8 in a developing container 85 containing a toner 84 as a one-component developer.
There is an elastic roller 82 that is in pressure contact with the developing roller 81 at a position upstream of the developing roller 81 in the rotation direction, and by rotating in the direction of arrow D, the toner 84 is supplied onto the developing roller 81. The toner 84 supplied onto the developing roller 81 is
The toner is conveyed as the developing roller 81 rotates, and electric charges are imparted by friction at the contact portion between the elastic blade 83 and the developing roller 81 to form a thin layer. Then, the thinned toner 84
Is conveyed by the developing roller 81 and is supplied to the electrostatic latent image at the contact portion with the photoconductor 21 to be developed. After that, the toner 84 left undeveloped at the contact portion between the photoconductor 21 and the developing roller 81 is peeled off by the elastic blade 83. Also,
As described above, the new toner 84 is added by the elastic roller 82.
Are supplied to the developing roller 81, and the above-described operation is repeated.

Conventionally, the above-described operation is repeated, and the life of the developing device 80 (replacement time) is limited only when the toner is used up.
Therefore, the display device 8 displays the life and informs the user of it.

[0008]

However, the above-mentioned conventional non-magnetic one-component DC contact development system has the following problems.

An external additive such as silica adhering to the toner surface is embedded in the toner surface due to heat history generated by the developing roller 81 coming into contact with and rubbing against the photosensitive member 21, resulting in deterioration of fluidity. . By repeating this phenomenon, the developability and transferability may be deteriorated. In particular, when a pattern having a low print rate is passed through the toner, the toner is not applied to the developing device 8.
Although the image quality is within 0, the image quality is significantly deteriorated, and the life (replacement time) of the developing device 80 is reached in terms of image quality. But,
Since the toner remains in the developing device 80, the fact that the developing device 80 has reached the end of its life (replacement period) cannot be communicated to the user.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to accurately convey the user the exchange time of the developing device before the image quality deteriorates regardless of the presence or absence of toner in the developing device. An object is to provide an apparatus and a process cartridge.

[0011]

In order to achieve the above object, the present invention provides an image carrier, an exposure device for irradiating the image carrier with light modulated according to input image information, and the exposure device. And a developing device that makes the electrostatic latent image visible by the developer carried by the developer carrying member by contacting the image bearing member carrying the electrostatic latent image formed by the developing device. An integrating unit that integrates the temperature information of the agent transporting member and the operating time of the developer transporting member, a storage unit that stores the result integrated by the integrating unit, and the storage unit that stores the result based on the result stored in the storage unit. And a transmission means for transmitting the replacement time of the developing device to the user.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of the image forming apparatus according to this embodiment. In FIG. 1, the photosensitive drum 1 (φ30) as a latent image carrier is 1r in the direction of arrow A.
Rotate at ps. Photosensitive drum 1 has a DC voltage of -1150V
The dark potential -6 is uniformly applied by the charging roller 2 applied to the
It is charged to 00V and an electrostatic latent image is written on the photosensitive drum 1. The laser power is adjusted so as to be −150 V when the entire surface of the laser light is exposed.

The laser scanner as the exposure device 5 uses a photosensitive drum to turn on / off the laser light which is input to the image forming device or is controlled in accordance with an image signal such as a test pattern created inside the device body. 1 to form an electrostatic latent image on the photosensitive drum 1.

Then, the electrostatic latent image is developed by the developing device 10 arranged close to the photosensitive drum 1 and visualized as a toner image. In this embodiment, the photosensitive drum 1 and the developing device 10 are configured as a process cartridge and can be attached to and detached from the image forming apparatus. Further, in the present embodiment, so-called "reverse development" is performed in which a toner image is formed on the exposed portion.

The visualized toner image on the photosensitive drum 1 is transferred onto the paper 9 as a recording medium by the transfer roller 6, and the transfer residual toner remaining on the photosensitive drum 1 without being transferred is scraped off by the cleaning blade 3. The photosensitive drum 1 that has been collected, stored in the waste toner container 4, and cleaned repeats the above-described operation.

On the other hand, the paper 9 on which the toner image has been transferred is fixed by the fixing device 7, discharged to the outside of the device, and the printing operation ends.

In the above-described developing device 10, the elastic roller 12 is in contact with the contact portion of the elastic blade 13 with the surface of the developing roller 11 on the upstream side in the rotating direction of the developing roller 11, and is rotated. Supported as possible. still,
As this structure, a foam skeletal sponge structure or a fur brush structure in which fibers such as rayon and nylon are planted on a core metal is preferable from the viewpoint of supplying the toner 14 to the developing roller 11 and stripping the undeveloped toner. In this embodiment, the elastic roller 12 having a diameter of 16 mm and having a polyurethane foam provided on a core metal is used. The contact width of the elastic roller 12 with respect to the developing roller 11 is effectively 1 to 6 mm, and it is preferable that the contacting portion of the elastic roller 12 has a relative speed.
In the present embodiment, the contact width is set to 4 mm, and the peripheral speed of the elastic roller 12 is set to 80 mm / s during the developing operation by a driving unit (not shown) at a predetermined timing with arrow D.
It is driven to rotate in the direction of.

On the downstream side of the elastic roller 12, an elastic blade 13 is supported by a blade supporting sheet metal, and the vicinity of the free end side tip is provided in surface contact with the outer peripheral surface of the developing roller 11. ing. This structure is composed of a rubber material such as silicon or urethane, or a thin metal plate of SUS or phosphor bronze having spring elasticity as a base, and a rubber material bonded to the contact surface side with the developing roller 11. Further, the contact direction is a so-called counter direction in which the front end side is located upstream of the contact direction with respect to the rotation direction of the developing roller 11. The elastic blade in this embodiment has a structure in which a plate-shaped urethane rubber having a thickness of 1.0 mm is bonded to a blade supporting sheet metal. Further, the contact pressure with respect to the developing roller 11 is 25 to 35 g / cm (the linear pressure is measured by inserting three thin metal plates having a known friction coefficient into the contact portion, and pulling out one of the central plates with a spring alone. (Converted from value)
Is set to.

The developing roller 11 is rotationally driven in the direction of arrow B, and the surface thereof has a high probability of rubbing against the toner 14,
In addition, the toner 14 has appropriate irregularities for favorably carrying the toner 14. In this embodiment, the diameter is 16 mm,
A developing roller 11 having a length of 240 mm and a thickness of 4 mm coated with an acrylic / urethane-based silicone rubber layer is used.
Roller resistance 10 ⁴ to 10 ⁶ Ω, surface roughness Rz 5 to 9 μ
m, and the hardness was 45 ° in Asker C hardness (weight 1 kg). Further, the developing roller 11 is pressed into contact with the photosensitive drum 1, the amount of the developing roller 11 entering the photosensitive drum 1 is 70 μm, and the peripheral speed of the photosensitive drum 1 is 94.2 mm / s and the peripheral speed is 170 mm / s.

Here, for the measurement of the resistance value, an aluminum roller having a diameter of 30 mm and the developing roller are brought into contact with each other over the entire length with a contact load of 500 gF, and the aluminum tube is rotated at 0.5 rps. Then, a DC voltage of 400 V is applied to the developing roller. A resistance of 10 KΩ is arranged on the ground side, the voltage across the resistance is measured, the current is calculated, and the resistance of the developing roller 11 is calculated. The toner 14 in 10 is sent toward the elastic roller 12 as the stirring member 15 rotates in the direction of arrow C.

Next, the toner 14 is carried to the vicinity of the developing roller 11 as the elastic roller 12 rotates in the direction of arrow D, and rubs against the abutting portion between the developing roller 11 and the elastic roller 12. As a result, they are triboelectrically charged and adhere to the developing roller 11. After that, as the developing roller 11 rotates in the direction of arrow B, the developing roller 11 is sent under pressure contact with the elastic blade 13 to form a thin layer on the developing roller 11.

In the present embodiment, the toner 14 is a non-magnetic one-component developer and has excellent transferability as described above, and the transfer residual toner remaining on the photosensitive drum 1 without being transferred is transferred to the blade or the fur. A toner having advantages such as less wear of the photosensitive drum 1 due to high lubricity when cleaning by a cleaning means such as a brush, that is, a toner having a spherical shape and a smooth surface is used. .

Further, 1.5 wt% of hydrophobic silica is added to this.
By externally adding, the negative-polarity toner 14 which is excellent in transferability as described above and which is less worn during cleaning of the photosensitive drum 1 is manufactured and used.

In this embodiment, a good charge amount is −40 to −20 μC / g, a good toner coat amount is 0.4 to 1.0 mg / cm ² , and a toner layer thickness is 10 to 2
It is set so that 0 μm can be obtained.

Next, the toner 14 is uniformly conveyed to the developing section, which is a section facing the photosensitive drum 1. At this developing contact portion, the thin toner layer formed on the developing roller 11 is developed as a toner image on the electrostatic latent image on the photosensitive drum 1 by a DC voltage applied to the developing roller 11 from a power source (not shown). To be done.

The undeveloped toner that has not been consumed in the developing section is rotated by the developing roller 11 and the developing roller 11 is rotated.
Will be collected from the bottom. This collected developing roller 11
The undeveloped toner on the upper side is the elastic roller 12 and the developing roller 11
Is peeled off from the surface of the developing roller 11 at the contact portion with. Most of the peeled toner is conveyed along with the rotation of the elastic roller 12 and the toner 14 in the developing container 16 is conveyed.
And the charge of the toner 14 is dispersed. At the same time, new toner is supplied onto the developing roller 11 by the rotation of the elastic roller 12, and the above-described operation is repeated.

When the toner 14 is hardly consumed at the contact portion between the photosensitive drum 1 and the developing roller 11,
The toner 14 is repeatedly subjected to a history of heat generated by sliding friction at the contact portion between the photosensitive drum 1 and the developing roller 11, and external additives such as silica adhering to the toner surface are embedded in the toner surface, resulting in deterioration of fluidity. Invite. By repeating this phenomenon, transferability deteriorates.

FIG. 2 is a diagram showing the relationship between the temperature (ΔT) of the developing device and the developing roller rotation time. FIG. 3 is a diagram showing the relationship between the product of the developing device temperature (ΔT) and the developing roller rotation time and the transfer efficiency.

As shown in FIG. 3, the temperature of the developing device (Δ
The transfer efficiency decreases as the product of T) and the developing roller rotation time increases. Therefore, if, for example, the transfer efficiency of 80% is the life of the developing device (replacement time), when the product of the temperature of the developing roller and the rotation time of the developing roller reaches 600 k or more, this developing device will reach the end of life (replacement time). You can judge that

In the present embodiment, the developing roller surface temperature ΔT shown in FIG. 2 is expressed as a function (ΔT of the rotation time t of the developing roller 11).
= 3.4 × t ^0.5 ), the arithmetic processing unit 16 shown in FIG. 1 calculates the temperature information ΔT based on this function, integrates the calculated temperature information ΔT and the developing roller rotation time, and obtains the obtained result. It is stored in the memory 17 shown in FIG. Further, as shown in FIG. 3, the product of the temperature (ΔT) of the developing roller 11 and the developing roller rotation time is determined from the transfer efficiency corresponding to the degree of deterioration of the image quality, and when the determined value is reached, the arithmetic processing unit 16 Judgment with, before the image quality deteriorates significantly,
The life of the developing device (replacement time) is transmitted to the user.

The arithmetic processing unit 16 includes an integrating circuit, a judgment processing circuit, and the like. For example, a CPU for performing the above-mentioned arithmetic processing and judgment processing and a work area and various tables used by the CPU when executing the processing. RA where information such as
It is assumed that it is composed of M, a ROM in which programs and control data of the CPU are stored, a programmable timer for measuring the rotation time of the developing roller 11, and peripheral circuits thereof.

In the above configuration, the arithmetic processing unit 16 transmits a signal indicating the end of life to the display unit 8 for transmission to the user, and the display unit 8 receiving the signal from the arithmetic processing unit 16 indicates the end of life. A display indicating that there is is performed.

As described above, according to this embodiment,
The product of the temperature of the developing roller and the rotation time of the developing roller is obtained, and the time when the image quality deteriorates can be determined as the life of the developing device based on the relationship between the product and the transfer efficiency corresponding to the degree of deterioration of the image quality. This makes it possible to notify the user of the life (replacement time) of the developing device before the image quality significantly deteriorates.

In this embodiment, the developing device is described as a process cartridge which can be attached to and detached from the main body of the image forming apparatus. However, the present invention is not limited to this, and various modifications can be made. For example, it may be used as a developing device that is fixed in the carrying device main body and replenishes only with toner, and the developing device, the photosensitive drum, the cleaning blade,
The waste toner container and the charging device may be integrally formed and used as a process cartridge that is attachable to and detachable from the main body of the carrying device. As a result, a configuration that is user-friendly and excellent in handling can be achieved.

In this embodiment, the developing roller surface temperature ΔT is a function of the rotation time t of the developing roller 11 (ΔT = 3.4
Xt ^0.5 ), and the calculation is performed based on this function, but the function is not limited to this, and it goes without saying that other approximate expressions may be used.

Further, the transfer efficiency for judging the life (replacement time) of the developing device is not limited to 80%.

[Other Embodiments] Next, other embodiments of the present invention will be described in detail with reference to the drawings.

In the above-described embodiment, the arithmetic processing unit 16
Although the memory 17 for storing the result obtained from the above is provided on the image forming apparatus side, in another embodiment, the memory 17 is integrally housed in the process cartridge which is detachably mounted.

FIG. 4 is a sectional view showing the structure of an image forming apparatus according to another embodiment. As shown in FIG. 4, the memory 18 for storing the result of the arithmetic processing unit 16 is integrally housed in the process cartridge which is detachably mounted, so that the process cartridge can be attached and detached from the image forming apparatus main body. Since the individual information of the process cartridge is stored in the memory 18, even if the process cartridge is mounted on a different image forming apparatus, the life (replacement time) of the process cartridge can be accurately transmitted to the user before the image quality significantly deteriorates. You can

Even when the present invention is applied to a system composed of a plurality of devices (for example, host computer, interface device, reader, printer, etc.), a device composed of one device (for example, copying machine, facsimile) Device).

Further, an object of the present invention is to supply a storage medium having a program code of software for realizing the functions of the above-described embodiment to a system or apparatus, and to supply the computer (CPU or MP) of the system or apparatus.
It goes without saying that U) is also achieved by reading and executing the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy (registered trademark) disk,
Hard disk, optical disk, magneto-optical disk, CD-
ROM, CD-R, magnetic tape, non-volatile memory card, ROM, etc. can be used.

Further, not only the functions of the above-described embodiments are realized by executing the program code read by the computer, but also the OS (operating system) running on the computer based on the instructions of the program code. It is needless to say that this also includes a case where the above) performs a part or all of the actual processing and the processing realizes the functions of the above-described embodiments.

Furthermore, after the program code read from the storage medium is written in the memory provided in the function expansion board inserted into the computer or the function expansion unit connected to the computer, based on the instruction of the program code, It goes without saying that a case where the CPU provided in the function expansion board or the function expansion unit performs a part or all of the actual processing and the processing realizes the functions of the above-described embodiments is also included.

[0047]

As described above, according to the present invention,
Regardless of the presence / absence of toner in the developing device, it is possible to accurately notify the user of the replacement time of the developing device before the image quality deteriorates.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the structure of an image forming apparatus according to this embodiment.

FIG. 2 is a diagram showing a relationship between a developing device temperature (ΔT) and a developing roller rotation time.

FIG. 3 is a diagram showing a relationship between a product of a developing device temperature (ΔT) and a developing roller rotation time and a transfer efficiency.

FIG. 4 is a sectional view showing a structure of an image forming apparatus according to another embodiment.

FIG. 5 is a diagram showing a structure of a conventional image forming apparatus using a non-magnetic one-component DC contact developing system.

[Explanation of symbols]

1 photosensitive drum 2 charging roller 3 cleaning blade 4 Waste toner container 5 Exposure unit 6 Transfer roller 7 Fixing device 8 display devices 9 Paper (transfer material) 10 Development device 11 Developing roller 12 Elastic roller 13 Elastic blade 14 Toner 15 Stirring member 16 arithmetic processing unit 17 memory

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H027 DA13 DA32 DA39 DD02 DE04                       DE07 DE09 EC06 EC07 EC10                       EC15 EC18 ED08 EE01 EE08                       GA30 HB02 HB13 HB15 ZA07                 2H071 BA05 BA33 DA08 DA13 DA15                       DA32                 2H077 AB03 AB14 AC04 AD02 AD06                       AD13 AD17 AE03 BA09 DA15                       DA18 DA20 DA22 DA78 DB10                       EA14 GA02 GA03

Claims (5)

[Claims] 1. An image carrier, an exposure device for irradiating the image carrier with light modulated according to input image information, and an image carrier for carrying an electrostatic latent image formed by the exposure device. In an image forming apparatus having a developing device that makes the electrostatic latent image visible by the developer conveyed by the developer conveying member, temperature information of the developer conveying member and operating time of the developer conveying member, And a storage unit that stores the result accumulated by the accumulation unit, and a transmission unit that transmits the replacement time of the developing device to the user based on the result stored in the storage unit. An image forming apparatus characterized by. 2. The image forming apparatus according to claim 1, wherein the transmitting unit displays on the display device that the developing device is to be replaced. 3. The image forming apparatus according to claim 1, wherein the image carrier and the developing device are detachably attached to the image forming apparatus main body as a process cartridge. 4. A process cartridge which is detachably attached to the image forming apparatus main body according to claim 1. 5. The process cartridge according to claim 4, wherein a storage unit that stores the result accumulated by the accumulating unit is integrally housed.