JP2002244487A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable image forming device where a faulty cleaning and fusion or the like are prevented from occurring all through its serviceable life by optimizing the applying amount of solid lubricant to the surface of a photoreceptor drum even when a developing cartridge is exchanged in an image forming device using toner of a small particle size or toner being fine particles obtained by a polymerization method. SOLUTION: This image forming device is provided with a lubricant film forming means bringing the solid lubricant into contact with a rotating brush and coating an image carrier with the lubricant stuck to the brush so that the coating film consisting of the lubricant is formed on the surface of the image carrier, and a developing means for developing an electrostatic latent image formed on the image carrier with the toner. The developing means is included in a cartridge constituted to be attached to/detached from a device main body, and the amount of the lubricant applied to the surface of the image carrier is controlled on the basis of information concerning the using state of the cartridge.

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 employing an electrophotographic recording system, such as a copying machine or a laser printer, and more particularly, to a cartridge having developing means and being detachably mountable to the apparatus body, and an image carrier. And a means for applying a lubricant to the surface of the image forming apparatus.

[0002]

2. Description of the Related Art Generally, in an electrophotographic laser printer, the surface of a photosensitive drum as an image carrier is uniformly charged by a charging means, and a laser beam modulated in accordance with image data is irradiated. An electrostatic latent image is formed. This latent image is reversal-developed at a development site by a developing unit disposed opposite to the photosensitive drum, and is visualized as a toner image. After the toner image is electrostatically transferred to the sheet by the transfer unit, the toner image is permanently fixed on the sheet by the fixing unit. Further, the toner remaining on the photosensitive drum without being transferred after the transfer is removed by a cleaning unit, and is prepared for the next image forming step.

In recent laser printers, it is not necessary for the user to perform maintenance such as replacement of consumable parts such as a photosensitive drum and a developer, which is difficult to replace, and maintenance of a residual toner. Many adopt a simple process cartridge system. For example, various types of cartridges, such as a developing cartridge in which a container containing toner and developing means are integrated, a drum cartridge in which a photosensitive drum and a charging means and a cleaning means are integrated, or a cartridge in which a developing cartridge and a drum cartridge are further integrated, and the like. Various types of process cartridges have been proposed. For these process cartridges, a warning of the life is notified according to the degree of wear of each of the process cartridges, and the user can replace them separately. In addition, since it is designed to optimize the life of each cartridge, a stable and good image can always be obtained until the life of the cartridge. There is an advantage that replacement can be easily performed by the user.

Conventionally, an elastic blade made of polyurethane or the like is often used for cleaning means because of its good cleaning properties. The physical properties of the elastic blade and the manner in which the elastic blade abuts on the photosensitive drum are greatly affected by the ease of cleaning depending on the degree of adhesion of the transfer residual toner to the photosensitive drum, the surface properties of the photosensitive drum, and the like. Also, the cleaning properties are greatly affected by the physical properties such as the toner shape, particle size, and material.Therefore, it is necessary to select a blade suitable for it and set the appropriate angle and contact load to the photosensitive drum. is there. In the actual selection and setting of the elastic blade, it is the present situation that trial and error are repeated to find the optimum conditions.

On the other hand, the cleaning performance and the degree of wear of the surface layer of the photosensitive drum differ depending on the actual operating environment, particularly the fluctuation of temperature and humidity. Some photosensitive drums are provided with a cleaning brush that rotates while being in contact with the photosensitive drum. Normal,
This cleaning brush is disposed on the upstream side of the elastic blade in the rotation direction of the photoconductor drum, and is used for scraping and collecting residual toner on the photoconductor drum after transfer, or for facilitating cleaning with the elastic blade. ing. For this reason, some cleaning brushes are grounded or a bias is applied to weaken the adhesion of the transfer residual toner to the photosensitive drum.

In recent years, higher image quality, that is, higher quality such as high resolution, sharpness, halftone, and photographic reproducibility has been demanded, and reducing the particle size of toner is an effective means. In addition, as a method for efficiently producing a fine particle toner having a narrow particle size distribution as compared with the conventional mechanical pulverization and classification method, a spherical particle toner having a nearly spherical shape produced by a polymerization method has been adopted in recent years.

However, in the case of the small particle size toner, the transfer residual toner remaining on the photosensitive drum after the above-mentioned transfer is firmly attached to the photosensitive drum, and it is difficult to sufficiently clean the toner. In particular, spherical toners produced by a polymerization method or the like have poor cleaning properties due to reservoirs that easily pass through the elastic blade, and are a serious problem in using fine particle toners.

Therefore, in order to solve these problems,
Various proposals have been made. For example, it is effective means to increase the contact pressure of the elastic blade to the photosensitive drum or to provide a cleaning brush as a cleaning auxiliary member as described above.

As a more reliable cleaning method, it has been proposed to supply a material which reduces the friction coefficient of the photosensitive drum to the surface. For example, a method has been proposed in which a solid lubricant made of zinc stearate or the like is applied to the surface of a photosensitive drum via a brush. By reducing the coefficient of friction on the surface of the photoreceptor drum, the frictional force with the toner can be reduced, making cleaning with an elastic blade and recovery with a fur brush easy, and an effective means for obtaining sufficient cleaning performance. is there.

Further, since the toner which is difficult to clean has a strong adhesive force with the photosensitive drum, the toner is deposited on the photosensitive drum when the image forming operation is repeatedly performed. Fusing easily occurs. In this fusing, silica or the like externally added to the toner to stabilize the performance to be charged against fluctuations in the environment and durability generally passes through the cleaning blade to form a fusing nucleus, and the toner adheres thereon. Things. However, by applying a solid lubricant to the surface of the photoreceptor drum, the slipperiness of the surface of the photoreceptor drum can be improved, the external additive can be prevented from slipping off from the cleaning blade, and the occurrence of fusion can be prevented.

[0011]

However, in the conventional cleaning device which applies the above-mentioned solid lubricant to the surface of the photosensitive drum, there is a problem that performance deteriorates with time. That is, although good cleaning performance is initially exhibited, there is a problem that the amount of the solid lubricant applied becomes insufficient due to the durability of repeating the image forming operation, resulting in poor cleaning and fusion.

In particular, when the above-mentioned cartridge is used up and replaced with a new one, and the durability is repeated, the above problem is likely to occur. This is because the amount of lubricant applied tends to be insufficient when the surface properties of the photoreceptor drum are deteriorating due to endurance. The main cause is that the ink is easily ejected onto the photosensitive drum (initial ejection). In particular, at the beginning of use of the developing cartridge, a lot of free external additives are present in the contained toner, and the discharge of the external additives is remarkable.

In recent color printers,
It has four color developing cartridges containing yellow, magenta, cyan, and black toners, and if these cartridges are replaced at the same time, the above-described problem is more likely to occur.

Therefore, the present invention provides an image forming apparatus using a small particle size toner or a fine particle toner formed by a polymerization method, in which the amount of the solid lubricant applied to the surface of the photosensitive drum can be properly adjusted even when the developing cartridge is replaced. Accordingly, it is an object of the present invention to provide a highly reliable image forming apparatus in which cleaning failure, fusion, and the like do not occur throughout the durability life.

[0015]

In order to solve the above-mentioned problems, a typical configuration of an image forming apparatus according to the present invention is such that a solid lubricant is brought into contact with a rotating brush and the lubricant attached to the brush is imaged. A lubricant film forming means for applying to the carrier and forming a film with a lubricant on the surface of the image carrier; and a developing means for developing the electrostatic latent image formed on the image carrier with toner. In the image forming apparatus, the developing unit is included in a cartridge detachably attached to the apparatus main body, and controls a coating amount of a lubricant applied to a surface of the image carrier based on information on a use state of the cartridge. It is characterized by doing.

[0016]

[First Embodiment] A first embodiment of an image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a main part of an image forming apparatus according to the present embodiment, FIGS. 2 and 3 are diagrams illustrating a shape factor of toner, FIG. 4 is a diagram illustrating a lubricant film forming unit, and FIG. FIG. 5 is a diagram for explaining the amount of ingress of the image carrier into the image carrier.

(Overall Configuration) First, the overall configuration of the image forming apparatus will be described with reference to FIG. The image forming apparatus according to the present embodiment is connected to a host such as a personal computer or a workstation (not shown), and receives image forming information via a video interface in response to a recording request from the host. Based on the image forming information, toner images of each color are sequentially formed by image data decomposed into four colors of yellow Y, magenta M, cyan C, and black K, and these are superimposed on an intermediate transfer member to form a sheet such as paper. To obtain a full-color image.

In FIG. 1, a photosensitive drum 1 as an image carrier is driven to rotate at a peripheral speed of about 120 mm / sec in a direction indicated by an arrow A in FIG. As a result, a lubricant film is formed on the surface. Then, the surface of the photosensitive drum 1 is uniformly charged to a dark portion potential VD of about -600 V by applying a DC bias with an AC bias superimposed on a metal core of the charging roller 2 as a contact charging means. Next, scanning exposure is performed at a resolution of 600 dpi by the optical unit 3 that is ON / OFF controlled in accordance with the image data of the first color (Y), and the first electrostatic latent image having a bright portion potential VL of about -200 V is applied. An image is formed.

The thus formed electrostatic latent image is developed and visualized by a rotary developing device 4, which is a developing device 4a containing four color toners.
To d are integrally formed, and are rotated (in the direction of arrow B in the figure) to the positions facing the photosensitive drum 1 when forming images of the respective colors. Then, the toner of a predetermined layer thickness is held in a sleeve of the developing device, and the toner is rotated and driven, and a DC bias of a predetermined AC bias is applied to a core of the sleeve to perform development. Each of the developing devices 4a to 4d can be individually replaced as a single developing cartridge depending on the degree of consumption.

First, the first electrostatic latent image is formed by a first developing device 4a containing a yellow toner as a first color toner.
Is developed and visualized. Contact as development method,
Although it can be used regardless of non-contact, in the present embodiment, a jumping development method using a non-magnetic one-component toner that combines image exposure and reversal development is used.

The visualized toner image of the first color is
Electrostatic transfer (primary transfer) is performed on the surface of the intermediate transfer member 5 at a first transfer portion 6a which is a nip portion with the intermediate transfer member 5 as a second image carrier. The intermediate transfer member 5 forms a conductive elastic layer and a surface layer having releasability on a cylinder, and has a peripheral length longer than the maximum length of a sheet that can be passed. While being pressed against the photosensitive drum 1 with a predetermined pressing force, the peripheral speed of the photosensitive drum 1 is substantially the same as the peripheral speed of the photosensitive drum 1 in a direction opposite to the rotational direction of the photosensitive drum 1 (arrow C in the figure). Direction). A voltage (primary transfer bias) having a polarity opposite to the charge polarity of the toner is applied to the cylinder of the intermediate transfer member 5 by the high-voltage power supply 7, whereby the toner image formed on the surface of the photosensitive drum 1 is transferred to the intermediate transfer member 5. 5 is electrostatically transferred to the surface.

The photosensitive drum 1 after the primary transfer has been completed
The toner remaining on the surface is removed by the cleaning device 8 and used for the next latent image formation. The cleaning device for the residual toner will be described later in detail.

Subsequently, the same process is repeated, and in each case, the toner image of the second color developed with the magenta toner,
A color toner image is formed by sequentially transferring the third color toner image developed with cyan toner and the fourth color toner image developed with black toner on the surface of the intermediate transfer member 5 in a superimposed manner. . Thereafter, the transfer belt 9 separated from the surface of the intermediate transfer member 5 is pressed against the surface of the intermediate transfer member 5 with a predetermined pressing force and is driven to rotate. The transfer belt 9 is supported by a transfer roller 9a and a tension roller 9b, and a voltage (secondary transfer bias) having a polarity opposite to the charging polarity of the toner is applied to the transfer roller 9a by a high-voltage power supply 10 so that the second transfer bias is applied. The color toner image laminated on the surface of the intermediate transfer body 5 is collectively transferred (secondarily transferred) to the surface of the sheet P conveyed to the second transfer portion 6b at a predetermined timing.
After being fixed as a permanent image, the sheet is discharged out of the apparatus to obtain a desired color print image.

Further, the toner remaining on the surface of the intermediate transfer body 5 after the completion of the secondary transfer is removed by the intermediate transfer body cleaning device 12 which comes into contact with the surface of the intermediate transfer body 5 at a predetermined timing.

(Image Carrier) The photosensitive drum 1 serving as the image carrier is provided with an undercoat layer on a cylindrical conductive substrate made of aluminum or the like having an outer diameter of approximately φ60 mm, on which a charge generation made of a phthalocyanine compound is performed. A layer was formed, and a charge transport layer in which a hydrazone compound was dispersed in polycarbonate as a binder was further laminated thereon to form a layer.
This is a so-called photoconductive organic photosensitive drum.

Further, Teflon (trade name) which is a fluorine particle is dispersed in the charge transport layer of the photosensitive drum 1. Teflon functions as a lubricating substance and improves the slipperiness of the surface of the photosensitive drum, so that the load on the cleaning device is reduced and the spherical toner used in the present embodiment is easily cleaned.

(Toner) The toner used in this embodiment is
Contains 5-30 (% by weight) of a low softening substance and has a shape factor SF1 of 1
This is a substantially spherical one-component non-magnetic toner having a particle size of 5 to 8 μm and a shape factor SF2 of 100 to 150 and a shape factor SF2 of 100 to 140. In both image forming apparatuses of the present embodiment, spherical toner having good transferability is used because the image is transferred twice, that is, primary transfer and secondary transfer as described above.

As shown in FIG. 2, the shape factor SF1 is a numerical value indicating the ratio of the roundness of the shape of the sphere material, and the maximum length MX of an elliptical figure formed by projecting the sphere material on a two-dimensional plane.
LNG square is divided by figure area AREA and multiplied by 100π / 4. That is, it is defined by the following equation: SF1 = {(MXLNG) ^ 2 / AREA} * (100π / 4)

As shown in FIG. 3, the shape factor SF2 is a numerical value indicating the ratio of the unevenness of the material shape, and the square of the perimeter PERI of the figure formed by projecting the material on a two-dimensional plane is the figure area.
It is divided by AREA and multiplied by 100π / 4. That is, it is defined by the following equation: SF2 = {(PERI) ^ 2 / AREA} * (100π / 4). In this embodiment, SF2 uses a FE-SEM (S-800) manufactured by Hitachi, Ltd., and randomly samples the toner image 100 times. The image information is sent to an image analyzer (LUSEX3, manufactured by Nicole) via an interface. It was introduced, analyzed, and calculated from the above equation.

The toner used in the present embodiment is manufactured by a polymerization method. The toner has a substantially spherical shape due to the manufacturing method. The core contains an ester-based wax, the resin layer thereon has styrene-butyl acrylate, and the outermost layer has styrene-butyl acrylate. The shell is composed of styrene-polyester, and its specific gravity is about 1.05.
Silica, strontium titanate, and the like are externally added to stabilize the performance to be charged against environmental changes.

In the present embodiment, the spherical toner having a small particle diameter and high resolution and good transferability is described by a polymerization method. However, the present invention is not limited to this. The toner may be prepared by the mechanical pulverization and classification method described above, or may be subjected to a thermal or mechanical post-treatment to obtain a rounded toner. In addition, the toner may be a two-component developing toner or a magnetic toner.

(Cleaning Device) The cleaning device 8 used in the present embodiment has an elastic blade 8a, a toner collecting sheet 8b, and a waste toner collecting container 8c as shown in FIG. As described above, the toner remaining on the surface of the photosensitive drum 1 after the primary transfer is removed from the photosensitive drum 1 by the elastic blade 8a, and the waste toner is not scattered to the outside of the cleaning device 8 by the toner collecting sheet 8b. It is stored in the collection container 8c.

The elastic blade 8a is made of polyurethane rubber integrally held at the tip of a sheet metal 8f. As shown in FIG. 5, the elastic blade 8a enters the photosensitive drum 1 with a predetermined amount of approach δ and a set angle θ. Touched. In the present embodiment, as a result of finding the optimum condition by repeating trial and error, the rubber hardness is 68
° (JISA), the contact pressure to the photosensitive drum 1 is set to about 70 g / cm with θ = 32 ° and δ = 1.45.

(Lubricant Film Forming Means) Next, the lubricant coating device 20 which is a lubricant film forming means will be described. The lubricant coating device 20 is made of zinc stearate and has a pencil hardness of 2
The holder 22 to which the solid lubricant 21 of B is fixed is attached to the lubricant applying container.
24. The holder 22 is movably held by engaging with the guide 23, and is urged by a predetermined pressure in a direction indicated by an arrow G in FIG. So that the amount of penetration (the amount of penetration) is

The application brush 25 has conductive fibers planted in a base cloth and wound on a φ6 core to form a φ16 brush. In the present embodiment, rayon conductive yarn having a thickness of 3 denier is used as the conductive fiber, and the fiber density is reduced.
What was implanted in the base cloth with W weave to 200 k (books / inch ^ 2) was formed into a sheet shape, and spirally wound so as to ensure conduction with the cored bar.

The lubricant applying device 20 is configured to be able to contact and separate from the photosensitive drum 1 in a direction indicated by an arrow E at a predetermined timing by a mechanism using a solenoid (not shown).

When the lubricant applying device 20 is in contact with the photosensitive drum 1, the applying brush 25 is disposed so as to enter the photosensitive drum 1 at a constant amount.
In the present embodiment, the amount of entry of the application brush 25 into the photosensitive drum 1 is set to 1 mm, and the initial setting is such that the brush 25 is driven to rotate at a speed of 30 rpm in the direction of arrow D, which is the same rotation as the photosensitive drum 1.

(Control Configuration) By the way, each of the developing devices 4a to 4d containing the toner of each color has a storage unit.
Non-volatile readable and writable storage means Ra to d such as EEPROM
(See FIG. 1). These storage means Ra ~
d is electrically connected to the apparatus main body by a connector (not shown), and can exchange information with a control unit of the apparatus main body. That is, the information in the storage units Ra to d can be read and written by the control unit. In the present embodiment, it is configured to detect that each color developing cartridge has been replaced, and thereby increase the amount of application by the lubricant applying device 20. Details are shown below.

First, an individual identification number for recognizing each of the developing cartridges is input to the storage means Ra to d in advance. As the individual identification number, in the present embodiment, a code obtained by combining the manufacturing date of the cartridge with the manufacturing number of the day is used, but any identification number may be used as long as each cartridge can be distinguished. .

On the other hand, the apparatus main body has a detecting means (not shown) for detecting that the developing cartridge is detached from the main body. If it is detected that the cartridge has been removed and inserted again, the coded information of the individual identification number stored in the storage unit is read out,
RAM that stores necessary information that can be accessed by the control unit
Then, it is determined whether or not the information is the same as the information of the developing cartridge that has been used so far and stored in the storage device. If no means for detecting that the developing cartridge is attached to and detached from the main body is not provided, the storage means Ra to
The reading of the individual identification number stored in d may be executed each time the image forming operation is started in response to a print request from the host.

When it is determined that the developing cartridge has been replaced, the control unit controls to increase the rotation speed of the application brush 25 of the lubricant application device 20 and increase the application amount. For example, control is performed so as to rotate at about 1.3 times the speed initially set at 40 rpm.

In this embodiment, the storage means Ra to Ra
In addition to the individual identification number, a total number of times the cartridge has been used for image formation is stored in d. By storing the total number of times of image formation, it is possible to determine whether or not the replaced cartridge is new.

The above-mentioned initial discharge of the toner external additive disappears due to repetitive durability of the image forming operation of about 1000 times, so that the application is performed until the number of times of image formation stored in the storage unit reaches 1000 times. Control to increase the amount. The reading and writing of the total number of times of image formation to the storage unit by the control unit are performed each time the image forming operation is started in response to a print request from the host and each time the image forming operation is completed.

Further, when the replacement of the developing cartridge is performed continuously, for example, the developing device 4a containing the magenta toner continues to be used while the image forming frequency after the replacement is small. In the case of replacement, the rotation speed of the application brush 25 may be controlled so as to further increase the application amount. Also, the rotation time of the application brush 25 can be made variable using one rotation of the photosensitive drum other than during image formation, that is, during non-image formation such as during preparatory rotation before image formation or during post-processing after image formation. By doing so, the application amount may be adjusted.

As described above, it is detected that one of the developing cartridges of each color has been replaced with a new one, and the number of revolutions of the application brush 25 is changed for a predetermined period so that the application amount is increased by the lubricant application device 20. By adjusting the amount of the solid lubricant applied to the surface of the photoconductor drum 1 by using this method, the load on the cleaning device can be reduced. Therefore, it is possible to eliminate a defective cleaning and a defective image caused by fusing, etc. caused by toner passing through the elastic blade when the external additive is discharged when replacing the developing cartridge, and to provide a cleaning device which is stable for a long period of time. Can be.

In the above-described adjustment of the amount of lubricant applied to the surface of the photosensitive drum 1 in accordance with the rotation speed, the number of image formations, the number of replacements of the developing cartridge, etc. It is appropriately determined according to the capabilities of the toner, the photosensitive drum, the cleaning means, and the like.

In the present embodiment, the solid lubricant 21
Is used, but a metal salt of a higher fatty acid other than zinc stearate (so-called metal soap) may be used, or a solid wax mainly containing an ester of a higher fatty acid and a higher alcohol may be used. In short, if the solid lubricant on the block is scraped off with a brush and pulverized to be applied to the photoreceptor drum 1, the same effect can be exerted if the surface is slippery and the friction can be reduced. .

On the other hand, the selection of the material and hardness of the photosensitive drum 1, the toner and the solid lubricant 21 and the setting of the contact condition of the coating brush 25 so that a constant film is always formed on the surface of the photosensitive drum. Should be optimized for the system in consideration of the life of the photosensitive drum 1 and the like.

[Second Embodiment] A second embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings. FIG.
FIG. 7 is a configuration diagram of a main part of the image forming apparatus according to the present embodiment, and FIG. 7 is a diagram illustrating a lubricant film forming unit. Parts that are the same as those in the first embodiment are denoted by the same reference numerals. The description is omitted. In the first embodiment, the individual identification numbers and the total number of image formation times are stored in the storage units Ra to d. However, in the present embodiment, the sleeve driving time of the cartridge is stored instead of the total number of image formation times. It is intended to be.

(Apparatus Configuration) In the image forming apparatus according to the present embodiment, the rotary type developing device 4 is not provided with the fourth developing device 4d containing the black toner, but is provided with the fixed type black developing device 4e. ing. With such a configuration, it is possible to increase the capacity of the toner container in the black developing period, which is generally consumed in a large amount. This black developing device 4
e is detachable from the apparatus main body similarly to the other developing devices 4a to 4c, and a non-volatile readable and writable storage means Re such as an EEPROM is provided as a storage unit. The storage unit Re is electrically connected to the apparatus main body by a connector (not shown), and can exchange information with a control unit of the apparatus main body.

Here, the black developing device 4e develops the electrostatic latent image formed on the photosensitive drum 1 by jumping development using one-component magnetic toner. By using the magnetic toner, it is possible to reproduce black which is more preferable as an image than the non-magnetic toner.

In the present embodiment, the black toner is subjected to a mechanical impact force or a sphering treatment by heating as a post-process to the conventionally used pulverized toner in consideration of transferability and charging characteristics due to the use of the intermediate transfer member. ing. Thereby, the shape factor SF1 is 120 to 160, the shape factor SF2 is 115 to 140,
The average particle size is 6.4 μm.

The method for producing the toner will be described. After premixing styrene-butyl acrylate-butyl maleate-half ester copolymer as binder resin, magnetite, iron complex of monoazo dye, and low molecular weight polyethylene as wax, biaxial kneading extruder set at 130 ° C To perform melt mixing. After cooling the kneaded material, coarsely pulverize and finely pulverize with a pulverizer using a jet stream,
Further, after fine powder is cut by using an air classifier, spheroidizing treatment by mechanical impact force or heating is performed as a post-treatment, and hydrophobic silica or the like is mixed. As the sphering treatment by mechanical impact force or heating, the toner is pressed against the inside of the casing by centrifugal force by a high-speed rotating wing, and a mechanical impact force is applied to the toner by a compressive force or a frictional force. And the like.

As shown in FIG. 7, unlike the first embodiment, the cleaning device 13 according to this embodiment is provided with a cleaning brush to more reliably perform cleaning by the elastic blade 8a. The cleaning brush includes a brush roller 8d and a brush scraper 8e.

The configuration of the brush roller 8d is the same as that of the application brush 25, and the core 8h is grounded. The cleaning brush is disposed upstream of the elastic blade 8a in the rotation direction of the photosensitive drum 1 and abuts on the photosensitive drum 1 with an intrusion amount of 1 mm. Driven at speed. At this contact portion, the photosensitive drum 1 and the brush roller 8d move in opposite directions to each other to scrape residual toner on the photosensitive drum 1 after the primary transfer, or to weaken the adhesion of the residual toner to the photosensitive drum. , So as to facilitate cleaning with the elastic blade 8a.

When the above-described cleaning operation is repeatedly performed on the brush roller 8d, the brush fibers are clogged by the collected toner, and the cleaning performance is reduced. To prevent this, a brush scraper 8e, which is a member for scraping off the toner accumulated in the brush fibers, is provided. In this embodiment, as the brush scraper 8e, a flexible PET sheet having a thickness of 0.1 mm is attached to a sheet metal 8g and the free length thereof is set to 3 mm. The amount of the brush scraper 8e entering the brush roller 8d is
It is set to 1.5mm.

The toner remaining on the surface of the photosensitive drum 1 after the primary transfer is removed from the photosensitive drum 1 by the brush roller 8d and the elastic blade 8a constituting the cleaning device 13 by the cleaning device 13 having the above configuration. The cleaning device 8 is formed by the collection sheet 8b.
Is stored in the waste toner collecting container 8c without scattering to the outside.

(Control Structure) As described above, in this embodiment, the storage means Ra to c and Re store the individual identification numbers and the coded values obtained by integrating the sleeve drive time of the cartridge. Accordingly, in the case where the total number of image formation times is used as in the first embodiment, it is possible to more accurately grasp the state of the developer for an apparatus that rotates the sleeve even during non-image formation. Can be.

That is, it is possible to more accurately grasp the initial discharge of the developer. this is,
External additives that are free or attached on the toner at the beginning
The sleeve is embedded in the toner as the drive time of the sleeve becomes longer. The fact that a change in this state has a certain correlation with the drive time of the sleeve is used.

First, in response to a print request from the host, the control unit starts the storage means Ra to Ra every time the image forming operation starts.
The individual identification number and the accumulated sleeve drive time are read from c and Re. In this way, when the replacement of the cartridge is detected and the predetermined time is not reached, the control is performed so that the application amount is increased until the predetermined time is reached.

Here, unlike the first embodiment, a plurality of predetermined values are provided, and the application amount is controlled for each of the predetermined values. If the sleeve drive integration time is a small value,
Since the developing cartridge has begun to be used and the amount of external additive discharged is large, the amount of lubricant applied is increased. Then, control is performed so that the application amount is reduced as the sleeve drive integration time increases. For example, after replacing the developing cartridge with a new developing cartridge, the rotation speed of the coating brush is controlled so as to rotate at 1.3 times the initial speed until the sleeve driving integration becomes 30 minutes, and then 1.2 times until 60 minutes. 90
It controls to return to the initial setting speed after reaching 1.1 times until 90 minutes and 90 minutes.

By controlling in this way, it is possible to form a necessary lubricant film on the surface of the photosensitive drum 1 in accordance with a change in the state of discharge of the external additive, and a cleaning failure caused by toner slipping through the cleaning blade. In addition, it is possible to eliminate image defects due to fusion and the like.

On the other hand, the black toner produced by the pulverization and classification method used in the present embodiment has less initial discharge and is easier to clean than the spherical toner produced by the polymerization method. Therefore, in the case where the black monochrome printing is performed by the black developing device 4e, it is not necessary to increase the amount of the lubricant applied as described above. You don't have to.

Further, by controlling the lubricant applying device 20 to be separated from the photosensitive drum 1 at a predetermined timing when continuous printing of a single black color is performed, wasteful consumption of the solid lubricant 21 is achieved. Can also be avoided.

[Third Embodiment] Further, the photosensitive drum 1
FIG. 8 shows another method of adjusting the amount of the solid lubricant applied to the surface.
This will be described using the lubricant application device 27 shown in FIG. In the lubricant application device 27 according to the present embodiment, the holder 22 to which the solid lubricant 21 made of zinc stearate is fixed is housed in the lubricant application container 24, and the holder 22 is connected to the guide 23 by the lubricant moving means (not shown). It is engaged so as to be movable in the direction of arrow G. The application brush 25 is disposed so as to have a constant amount of entry into the photosensitive drum 1, and the solid lubricant 21 is set to have a predetermined amount of entry into the application brush 25. Is applied to the surface of the photoreceptor drum 1.

The moving means is provided to provide the solid lubricant 21.
The amount of application to the application brush 25 can be increased or decreased to increase or decrease the amount of application. Therefore, instead of making the rotation speed of the application brush 25 variable as described above, the application amount can also be controlled by increasing or decreasing the amount of entry.

In the case where the life of the photosensitive drum 1 is long, the lubricant moving means is designed to keep the shaving amount constant at a predetermined timing in consideration of the brittleness of the solid lubricant 21 due to durability. Can also be corrected. For example, the total rotation time of the application brush 25 may be stored, and correction may be made such that the solid lubricant 21 enters the application brush 25 by a fixed amount at predetermined time intervals by the moving means.

[Other Embodiments] FIG. 9 is a view for explaining a process cartridge according to the present invention. Parts that are the same as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In the image forming apparatus according to the present embodiment, the photosensitive drum 1, the charging roller 2, the cleaning device 8, and the lubricant applying device 20 for forming a lubricant applied film are integrated, and the process is detachable from the apparatus main body. The cartridge 30 is constituted.

By using a process cartridge, the user does not need to perform maintenance such as replacement of consumable parts such as the photosensitive drum 1 and the solid lubricant 21 which are difficult to replace, and processing of residual toner. When using the process cartridge system, the process cartridge 30
Of the photosensitive drum 1 according to the life of the
In order to maintain the hardness of the photosensitive drum 1 and the surface properties of the photosensitive drum 1 until the end of its life, the contact condition of the application brush 25 is designed to be optimized. This makes it possible to always obtain a stable and good image without any trouble until the life of the process cartridge 30, and the user can easily perform replacement when the life has expired. Note that the developing device 4 can be further integrated with the process cartridge 30.

FIG. 10 is a view for explaining a process cartridge according to the present invention. The same parts as those in the second embodiment are denoted by the same reference numerals, and description thereof is omitted.
In the image forming apparatus according to the present embodiment, a cleaning device 13 having a cleaning brush in a process cartridge 31 is provided. A lubricant coating device 27 for forming a lubricant coating on the surface of the photosensitive drum 1 includes:
Clean the brush roller 8d with a solid lubricant
It is used as a brush to apply 21. The lubricant coating device 27 is preferably configured to be able to contact and separate from the photosensitive drum 1 in the same manner as the lubricant coating device 20, and such a configuration will be described in the first and second embodiments. A similar effect can be obtained by applying the present invention.

[0071]

As described above, the image forming apparatus according to the present invention can be used in an image forming apparatus using a small particle size toner or a fine particle toner formed by a polymerization method even if a cartridge having a developing unit is replaced. A reliable image forming apparatus that can form a predetermined film by optimizing the amount of the solid lubricant applied to the surface of the image bearing member and can form a good image without any trouble over a long period of time. Can be provided.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a shape factor of a toner.

FIG. 3 is a diagram illustrating a shape factor of a toner.

FIG. 4 is a diagram illustrating a lubricant film forming unit.

FIG. 5 is a diagram illustrating the amount of elastic blades entering the image carrier.

FIG. 6 is a main part configuration diagram of an image forming apparatus according to a second embodiment.

FIG. 7 is a diagram illustrating a lubricant film forming unit.

FIG. 8 is a diagram illustrating a lubricant film forming unit according to a third embodiment.

FIG. 9 is a diagram illustrating a process cartridge according to another embodiment.

FIG. 10 is a diagram illustrating a process cartridge according to another embodiment.

[Explanation of symbols]

 Ra to d: storage means Re: storage means 1 ... photosensitive drum 2 ... charging roller 3 ... optical means 4a to d ... developing device 4e ... black developing device 5 ... intermediate transfer member 6a ... first transfer portion 6b ... second transfer Part 7: High-voltage power supply 8: Cleaning device 8a: Elastic blade 8b: Toner collection sheet 8c: Waste toner collection container 8d: Brush roller 8e: Brush scraper 8f: Sheet metal 9: Transfer belt 9a: Transfer roller 9b: Tension roller 10: High voltage power supply 11… Fixing device 12… Intermediate transfer body cleaning device 13… Cleaning device 20… Lubricant application device 21… Solid lubricant 22… Holder 23… Guide 24… Lubricant application container 25… Application brush 26… Pressure spring 27 … Lubricant application device 30… Process cartridge 31… Process cartridge

Continued on front page F term (reference) 2H027 DA27 DA39 DA45 DE07 EA09 EC06 EC11 ED28 EE03 EE07 EE08 EF09 2H134 GA01 GA06 GB02 HB09 HB18 HD04 HD05 HD11 HD19 KA28 KA33 KB06 KB08 KB12 KD08 KH05 KH15 LA01 LA02

Claims (5)

[Claims] 1. A lubricant film forming means for bringing a solid lubricant into contact with a rotating brush, applying the lubricant attached to the brush to an image carrier, and forming a film of the lubricant on the surface of the image carrier. An image forming apparatus having a developing unit for developing an electrostatic latent image formed on the image carrier with toner, wherein the developing unit is included in a cartridge detachably mounted on an apparatus main body; Based on your usage information,
An image forming apparatus, wherein an amount of a lubricant applied to a surface of an image carrier is controlled. 2. The information on the use state of the cartridge includes at least individual identification information, drive time information on a sleeve serving as a toner carrier of the developing unit, or information on the number of image formations of the cartridge. The image forming apparatus according to claim 1. 3. The method of controlling the amount of the lubricant to be applied includes: changing the number of rotations of the rotating brush per unit time, or changing the rotating time of the rotating brush, or controlling the rotation of the solid lubricant. 2. The image forming apparatus according to claim 1, wherein the control is performed by changing the amount of the brush to enter. 4. The image forming apparatus according to claim 1, wherein the cartridge has a non-volatile storage unit that stores information on a use state of the cartridge. 5. The image forming apparatus according to claim 1, wherein the means for cleaning the toner remaining on the image carrier has at least an elastic blade abutting on the surface of the image carrier.