JP2003122222A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide means for scraping and suppressing the fusing and filming liable to arise in a system having the smaller amount of chipping of an image carrying member without permitting the inclusion of polishing particles into toners and without losing the affinity unique to the urethane of a cleaning blade with the image carrying member. SOLUTION: This longer-life image forming device is <5 μm in the amount of chipping of the image carrying member per the number of copying sheets of 30,000 sheets, in which the cleaning means is a counter blade system and the cleaning blade constituted by forming the cleaning blade of a the thermoplastic or thermosetting polyurethane and forming a cured layer on at least the segment of the blade surface in contact with the image carrying member by impregnating this segment with an isocyanate compound, then thermally curing this compound is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic recording type image forming apparatus.

[0002]

2. Description of the Related Art In recent years, multifunctional machines having all output terminals such as copying machines, printers and fax machines have been widely accepted in the market. Although the electrophotographic system has been widely accepted as such a network-compatible output terminal, the Duty Cycle of the main body has been cited as one of the major problems. The service life is the limit of the number of sheets that can continue to operate normally without maintenance, but one of the greatest rates of duty cycle is the life of the photosensitive drum.

From an ecological point of view, it has become an absolute issue for us to eliminate waste, that is, reduce consumables, prolong the life of consumables, and improve reliability. With the progress of digitization from conventional analog devices, it has become an absolute issue for us to make the main unit cost analog equivalent or lower.

Further, in recent years, black-and-white machines have conventionally been the mainstream for copying machines and printers, but full-color originals or output files are rapidly increasing in offices. Not only the analog equivalent digital machine,
Body cost and running cost Black and white equivalent full color printers have become an absolute issue for us.
To that end, a technology that can dramatically reduce TCO (total required cost from the user's perspective) is desired.

Under such circumstances, a plurality of photoconductors and a transfer belt carrying a recording material are provided in recent years, and the recording material carried on the transfer belt has different colors formed on the respective photoconductors. A color image forming apparatus that obtains a color image by sequentially superposing and transferring toner images has become mainstream.

In an image forming apparatus that repeats the step of transferring a transferable toner image formed on the surface of an image carrier to a transfer material mainly composed of paper, at the time of transfer, it does not transfer to the transfer material and remains on the image carrier. It is essential that the residual toner is sufficiently removed each time.

Therefore, as a cleaning means, many proposals have been made in the past, but a cleaning blade made of an elastic material such as urethane rubber to scrape off the residual toner is simple and compact. It is widely used for its low cost and excellent toner removing function. As a rubber material for the cleaning blade, urethane rubber is generally used, which has high hardness and rich elasticity, and is excellent in abrasion resistance, mechanical strength, oil resistance and ozone resistance.

I) Nowadays, as a means for extending the life of copying machines, the surface of the recording image carrier used is made of a material that is not easily scraped, or fluorine fine particles are dispersed to impart slipperiness. Chemical means such as the above and physical means such as changing the charging method from the AC charging method and the DC charging method to the corona charging method have been taken. It has been confirmed that when compared with the AC charging method, the abrasion amount of the image bearing member is reduced to less than half in the corona charging method.

However, although the durability of the image bearing member has been remarkably extended by the above-mentioned method, on the other hand, since the image bearing member is less likely to be scraped off, the deposits adhering to the surface of the image bearing member are scratched. However, the problem of fusing and filming occurs, which causes defective images. Therefore, by changing the external additive formulation of the toner and increasing the amount of the external additive having a polishing effect, it is attempted to polish the surface of the image bearing member with the external additive interposed in the cleaning blade, or cleaning as a cleaning means. As a development of a technique for imparting a scraping ability to the blade itself, an attempt has been made to coat a cleaning blade with a substance such as nylon to increase the hardness of the blade edge.

On the other hand, since both ends of the image carrier are located in the margins of the recording paper, an image is not formed, and therefore, the amount of toner reaching the cleaning blade is significantly reduced at both ends in the longitudinal direction. ing. Therefore, it is known that the surface of the image bearing member is less likely to be worn at both ends of the image bearing member, and the slipperiness is locally deteriorated only in those portions. Therefore, attempts have been made to increase the hardness of the edges by coating both ends of the cleaning blade with the nylon material.

Ii) Further, the image carrier in the 4-drum system is prepared for each color station, and the cleaning device for removing the transfer residual toner on the image carrier is also installed for each station. Therefore, the amount of transfer residual toner reaching each cleaning device is remarkably smaller than the amount of transfer residual toner reaching a conventional one-drum type image carrier cleaning device, and full-color image formation in which four color toner amounts are uniformly consumed. Under the same conditions, the amount of transfer residual toner supplied to each of the four-drum system image carrier cleaning devices is simply 1% of the transfer residual toner amount supplied to the one-drum system image carrier cleaning device. Only / 4. Further, in the image forming apparatus having the intermediate transfer system, the apparatus for cleaning the transfer residual toner on the intermediate transfer body is different from the photosensitive drum for directly developing the image,
Once the image is transferred from the photoconductor drum, transferred to the intermediate transfer body, and transferred to the recording paper again, the transfer residual toner left on the intermediate transfer body is transferred to the cleaning device of the photoconductor drum. It is known that the amount of the transfer residual toner reaching the toner is considerably lower than that of the transfer residual toner. Further, in a cleaning device that removes the toner left on the transfer material carrier, an image is not directly formed on the recording material carrier, so the amount of toner reaching the cleaning blade is Extremely less than. Therefore, the cleaning blade of the drum cleaning device in the four-drum system, the cleaning blade of the intermediate transfer member cleaning device of the image forming apparatus having the intermediate transfer member, and the cleaning device of the transfer material carrying member are It was difficult to secure the slipperiness of the cleaning blade, and chattering and curling of the cleaning blade became a problem. Therefore, to ensure good cleaning even if the amount of toner supplied to the blade is small, the cleaning blade is coated with nylon so that the blade edge has a high hardness in order to ensure the slidability between the blade and the drum on the blade side. There have been taken various methods, such as liquefying and applying a lubricant to the blade.

[0012]

In the trial described in i), if the amount of the external additive having a polishing effect is increased, the image bearing is started from the portion where the external additive is embedded at the time of long-term durability. There was a problem that the image was distorted due to deep scratches in the circumferential direction of the body.

Further, in the attempt to extend to ii), the cleaning blade coated with nylon has a nylon edge at the blade edge, so that the affinity with the drum of polyurethane is lost, and conversely the toner is lengthened. It is impossible to prevent the toner from being uniformly blocked in the direction, which causes a problem that the toner easily slips through. Also,
A method such as applying a lubricant to the cleaning blade is troublesome for a service person and is also costly.

[0014]

The present inventor has completed the present invention as a result of extensive studies to solve the above problems.

The present invention is specified by the items (1) to (10) below.

(1) A recording image carrier, a charging means for charging the image carrier, a recording material carrier for carrying and conveying a recording material, and a toner image on the recording material carried on the recording material carrier. An image forming apparatus comprising an image forming means for forming, a means for transferring the toner image onto a transfer material, and a cleaning means for cleaning the recording material carrier, wherein the abrasion amount of the image carrier is the image forming apparatus 3 In a system having less than 5 μm per number of copies, the cleaning means is a counter blade type, the cleaning blade is made of thermoplastic or thermosetting polyurethane, and at least a portion of the surface of the blade that comes into contact with the recording carrier is An image forming apparatus comprising a cured layer formed by impregnating with an isocyanate compound and then heating and curing the same, (2) Abrasion amount of the image carrier A system having a size of less than 5 μm per 30,000 copies of the image forming apparatus is an electrophotographic photosensitive member in which the image bearing member has a surface layer containing at least carbon atoms and fluorine atoms, and is measured by XPS measurement on the surface of the photosensitive member. The image forming apparatus according to (1) above, wherein the mole fraction ratio F / C of carbon atoms to fluorine atoms is F / C = 0.01 to 1.0, (3) The amount of abrasion of the image carrier is the image forming apparatus 3
A system in which the number of copies is less than 5 μm per 10,000 sheets means that the binder resin contained in the surface layer of the image bearing member is one kind or a mixture of two or more kinds selected from polycarbonate, polyarylate and polyallyl ether. (1) The image forming apparatus described in (1) above, and (4) the charging means for charging the image carrier is of a corona charging type. ,
(5) Recording image carrier, charging means for charging the image carrier, recording material carrier for carrying and conveying recording material, and image for forming toner image on the recording material carried on the recording material carrier In an image forming apparatus including a forming unit, a unit for transferring the toner image to a transfer material, and a cleaning unit for cleaning the recording material carrier, the cleaning unit is a counter blade type, and the cleaning blade is thermoplastic or An image forming apparatus comprising a thermosetting polyurethane, wherein both end portions of the blade, which are in contact with the recording medium, are impregnated with an isocyanate compound and then cured by heating to form a cured layer. , (6)
In an image forming apparatus that transfers a toner image carried by a carrier to a recording material to form an image, a transfer bias is applied to an image carrier that directly or indirectly carries the toner image and a conductive member. Transfer means for transferring the toner image,
In an image forming apparatus having means for cleaning residual toner on the surface of the carrier and the conductive member, the cleaning means is a counter blade type, and the residual toner supplied to the cleaning means is extremely small, The cleaning blade is made of thermoplastic or thermosetting polyurethane, and is characterized in that at least a portion of the surface of the blade that comes into contact with the recording medium is impregnated with an isocyanate compound and then cured by heating to form a cured layer. (7) The image forming apparatus according to the above (6), wherein the image forming apparatus that supplies the cleaning unit with a significantly small amount of residual toner is a four-drum type full-color image forming apparatus. (8) Remaining toner supplied to the cleaning means is extremely small The image forming apparatus according to (6) above, wherein the leaning device is a cleaning device that cleans a surface of the recording material carrier that carries a recording material on which an image is transferred from the image carrier. 9) The cleaning device that supplies a significantly small amount of residual toner to the cleaning means is a cleaning device that cleans the surface of an intermediate transfer member to which an image is indirectly transferred from the image carrier. The image forming apparatus according to (6), (10) an image forming apparatus that transfers a toner image carried by a carrier to a recording material to form an image, and directly or indirectly carries the toner image. A carrier, transfer means for applying a transfer bias to the conductive member to transfer the toner image, and cleaning the surface of the carrier and the residual toner on the conductive member. In an image forming apparatus having a step, the cleaning unit is a counter blade system, and the toner forming the image is an irregular toner produced by a pulverization method, the cleaning blade is made of thermoplastic or thermosetting polyurethane, An image forming apparatus characterized in that at least a portion of the surface of the blade that comes into contact with the intermediate transfer member is impregnated with an isocyanate compound and then cured by heating to form a cured layer.

In the invention described in (1) above, since the cleaning blade is made by impregnating a polyurethane rubber blade with isocyanate and heat curing, unlike the nylon coat and the like, the blade edge is Retains the properties of urethane, the affinity between the blade and the drum does not change so much, and the slipperiness between the blade and the carrier can be improved. Therefore, there is no deterioration in the toner passing through the blade, and since the blade edge has a high hardness, the adhered matter adhering to the surface of the image carrier is scraped off,
It is also excellent in the effect of suppressing fusion and filming.

In the invention described in the above item (2), even when an image carrier having a small amount of abrasion in which fluorine atoms or fluororesin fine particles are dispersed in a binder of carbon atoms is used, the surface of the image carrier is used. Therefore, it is possible to prevent the cleaning blade from chattering (abnormal vibration) and curling without causing fusion or filming.

In the invention described in the above item (3), even when an image carrier having a small amount of abrasion developed for the purpose of prolonging the life, such as polyarylate, is used, the surface of the image carrier is fused or fused. It is possible to prevent chattering (abnormal vibration) and curl of the cleaning blade without filming.

In the invention described in (4) above, it is superior to AC charging and contact charging in that the surface of the image carrier is uniformly charged to a predetermined potential, but the image Even in an image forming apparatus that is charged by the corona charging method, which has been a bottleneck in the generation of fusion and filming because the carrier is not scraped, good cleaning can be performed without fusion or filming. It has become possible.

In the invention described in (5) above, generally, the amount of toner reaching the cleaning blade is small,
It has become possible to suppress the occurrence of fusion and filming at both ends in the longitudinal direction, which are said to have a small abrasion amount of the image carrier. Further, unlike nylon coating, etc., the blade edge retains the property of urethane, the affinity between the blade and the drum does not change so much, and the sliding property between the blade and the carrier is improved. Is possible, so
There is no deterioration in the toner passing through the blade.

In the invention described in (6) above, since the cleaning blade is made by impregnating a polyurethane rubber blade with isocyanate and heat curing, the blade edge retains the property of urethane. Therefore, the affinity between the blade and the drum does not change so much, and the slipperiness between the blade and the carrier can be improved. Therefore, the toner passing through the blade is not deteriorated, and good cleaning can be performed even in a system in which the amount of toner supplied to the blade is small.

According to the invention described in (7) above, even in a four-drum type full-color image forming apparatus, good cleaning can be performed without applying a lubricant to the blade.

In the invention described in (8) above, this enables good cleaning of the recording material carrying member without applying the blade lubricant.

In the invention described in (9) above, this allows good cleaning of the intermediate transfer member without applying a lubricant to the blade.

In the invention described in the above item (10), when the toner intervenes in the contact portion between the blade and the image carrier,
Even in an image forming apparatus that uses an irregular toner produced by a pulverization method, which is known to significantly inhibit the slipperiness of a substantially spherical polymer toner, without applying a lubricant to the blade. Good cleaning can be done.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an image forming apparatus according to an embodiment of the present invention to which the means described in (1) to (10) above is applied will be described. That is, a four-drum type color electrophotographic apparatus having image carrier cleaning and transfer belt cleaning will be described. FIG. 1 is a cross-sectional explanatory view showing the overall structure of the copying apparatus.

First, the schematic construction of the color electrophotographic copying apparatus will be described with reference to FIG. 1. Inside the apparatus main body 1, image forming sections Pa, Pb, P containing process means are incorporated.
c and Pd are arranged in the lateral direction, and each image forming unit Pa
, Pb, Pc, Pd below the belt drive roller 13,1
An endless transfer belt 130 is hung around 4,15.
The transfer belt 130 is rotated by rotating the belt drive roller 13 in the direction of the arrow by a drive motor (not shown). A cassette 10 stores a recording sheet P which is a recording material, and the recording sheet P stored in the cassette 10 is fed from the uppermost side. The skew feeding is corrected by the pair of registration rollers 7, and the sheet is conveyed onto the transfer belt 130 in synchronization with the image forming units Pa, Pb, Pc, and Pd. Reference numeral 12 is a conveyance guide for guiding the recording sheet P to the transfer belt 130 from the registration roller pair.

Next, the image forming portions Pa, Pb, Pc, P
Explaining the configuration of d, the photosensitive drum 3 which is an image carrier.
Primary chargers 2a, 2b, 2c, 2d having a, 3b, 3c, 3d and constituting process means around them, and developing devices 1a, 1
b, 1c, 1d, transfer chargers 24a, 24b, 24c, 24d, cleaning devices 4a, 4b, 4c, 4d, pre-exposure light source 113
a, 113b, 113c, 113d are provided respectively. A laser beam scanner is provided above the photosensitive drums 3a, 3b, 3c and 3d.

The primary chargers 2a, 2b, 2c and 2d are
Prior to exposing the photosensitive drums 3a, 3b, 3c, 3d,
The drum surface is uniformly charged, and the developing devices 1a, 1
b, 1c and 1d are for making visible images by attaching toners of respective colors of black, magenta, yellow and cyan to the electrostatic latent image formed on the surface of the drum by being exposed. The transfer chargers 24a, 24b, 24c, 24d are connected to the photosensitive drums 3a, 3d.
The toner images formed on b, 3c, and 3d are transferred onto the recording sheet P, and cleaning devices 4a, 4b, and 4 are used.
Numerals c and 4d are for removing the residual toner adhering to the drum surface after the image transfer. Pre-exposure light sources 113a, 113b,
Reference numerals 113c and 113d are for removing the surface potential of the photosensitive drums 3a, 3b, 3c and 3d, and the laser beam scanner has a semiconductor laser, a polygon mirror, an fθ lens, etc., and receives an input of an electric digital image signal. The laser beam modulated according to the signal is applied to the photosensitive drums 3a, 3
The exposure is performed by irradiating in the generatrix directions of b, 3c and 3d.

Reference numeral 32 is a separating charger for separating the recording sheet P conveyed on the transfer belt 3, and 9 is a fixing device for fixing the transferred image transferred to the recording sheet P. A fixing roller 51 having a heating means such as a heater therein and a pressure roller 52 in pressure contact with the fixing roller 51 are provided. 63
Is a discharge tray for stacking the recording sheets P discharged outside the apparatus.

The image forming operation will now be described. When an image forming operation start signal is input to the main body of the apparatus, the photosensitive drum 3a starts rotating in the direction of the arrow and is uniformly charged by the primary charger 2a, and the laser beam is emitted. The beam scanner irradiates the drum surface with laser light modulated by the image signal corresponding to the black component of the original image to form an electrostatic latent image (exposure). Next, black toner is supplied by the developing device 1a to form a visible toner image of the latent image.

On the other hand, the recording sheet P stored in the cassette 10 is fed, and after the skew feeding is corrected by the pair of registration rollers which are temporarily stopped, the recording sheet P is transferred to the toner image formed on the photosensitive drum 3a. And is conveyed onto the transfer belt 130. The recording sheet P sent to the transfer belt 130 is transfer-charged by the transfer charger 24a at the transfer portion of the image forming portion Pa, and the toner image is transferred to the recording sheet P. The above process is performed in the image forming parts Pb, Pc
, Pd, the magenta color toner image, the yellow color toner image and the cyan color toner image are sequentially transferred to the recording sheet P.

The recording sheet P on which the image transfer is completed is separated from the transfer belt 130 while being subjected to AC static elimination by the separation charger 32 at the left end portion of the transfer belt 130, and is conveyed to the fixing device 9. Then, the recording sheet P on which the image is fixed by the fixing device 9 is discharged to the discharge tray 63 outside the apparatus.

In the electrophotographic copying machine according to this embodiment, the maximum image width is about 290 mm on the A4 side, and the drum peripheral speed is 200 mm / sec.

By the way, as shown in FIG. 3, the photosensitive drum 1 includes a conductive substrate IX, a charge generating layer VIII coated thereon, and a charge transport layer VII coated thereon.
Furthermore, it further comprises a release layer VI coated thereon.

Next, the cleaning device for the image carrier of the present invention will be described. Cleaning devices 4a, 4b, 4c, 4
A cleaning blade abutted on the surface of the photosensitive drum A is held in the cleaning container d. The cleaning blade was an elastic blade mainly composed of urethane, and the part in which the surface of the blade that contacts the recording medium was impregnated with an isocyanate compound and then cured by heating to form a cured layer. As a method of manufacturing the blade,
Hardness manufactured from thermosetting polyester polyurethane
A JIS 70 degree cleaning blade is masked with a chemical resistant tape as shown in FIG. 2 (I in FIG. 2), 80
Immerse in MDI bath at ℃ for 30 minutes (II in Fig. 2), wipe off excess isocyanate and remove masking.
Cured in an oven at 0 ° C for 60 minutes (II in Fig. 2
I) was used. Contact angle of the blade 24 ° Contact pressure 33
(G / cm). The cleaning blade has a plate thickness of 2 mm, and the member Tc SUS (plate thickness 1.0) is arranged as a back plate. The free length of the cleaning blade is 10 mm. As the pre-exposure 113, 66
Light-emitting diode (element
GaAlAs), the half-value width which becomes 1/2 of the peak wavelength is about 25
nm and the exposure amount is 20 μJ / cm 2. About 50m from the pre-exposure 113 to the primary charger (not shown)
m / sec.

The fixing device 9 includes a fixing roller 51, a pressure roller 52, heat-resistant cleaning members 54 and 55 for cleaning each of them, roller heaters 56 and 57 installed in the rollers 51 and 52, and fixing. The roller 51 comprises a coating roller 50 for coating a release agent oil such as dimethyl silicone oil, a reservoir 53 for the oil, and a thermistor 58 for detecting the temperature of the surface of the pressure roller 52 and controlling the fixing temperature. . The recording material P to which the four color toner images have been transferred is mixed with the toner images and fixed to the recording material P by this fixing device, and a full color copy image is formed.

Regarding the characteristics of the color toner, first, as the two-component developer, a mixture of a polymerized toner prepared by the suspension polymerization method and a resin magnetic carrier prepared by the polymerization method was used. T / D of the obtained developer
The ratio was 8%. The magnetic carrier has a magnetization amount of 100 emu / cm ³ in a magnetic field of 1 kilo Oersted, a number average particle diameter of 40 μm, and a specific resistance of 1
0 ¹³ Ω · cm was used. The non-magnetic polymerized toner is a substantially spherical toner having a shape factor SF-1 of 115 and SF-2 of 110 and a smooth surface, a weight average particle diameter of 8 μm, and a specific gravity of 1. A toner having an average charge amount of 25 μc / g per unit mass of 05 g / cm ³ was used.

[0040]

EXAMPLES Examples of the present invention will be shown below, but the present invention should not be construed as limited by these examples.

Example 1 Using the image forming apparatus of the 4-drum system, XPS was used as the releasable layer IX of the photosensitive drum 1.
Measured mole fraction ratio of carbon and fluorine atoms F / C
However, F / C = 0.3% is used, roller charging is adopted as the charging method, and two copies with 10% image coverage at room temperature and normal humidity are intermittently copied for 30,000 copies. The image obtained on the 30,000th sheet was visually evaluated. The abrasion amount of the photosensitive drum was 4.5 μm / 30,000 sheets, but the photosensitive drum was prepared by using a cleaning blade having an isocyanate compound impregnated and then heat-cured to form a cured layer. The deposits generated on the surface were scraped off, and good cleaning was performed without deteriorating the slipperiness between the photosensitive drum and the blade.

(Comparative Example 1) As a comparison with Example 1, the cleaning blade used as the cleaning means using the image forming apparatus of the four-drum system does not have a hardened layer formed, and has a normal JIS hardness of 70. Of a thermosetting polyurethane, and the release layer IX of the photosensitive drum 1 is a mol of carbon atoms and fluorine atoms measured by XPS.
Use the one with a fraction ratio F / C of F / C = 0.3%, adopt roller contact charging as the charging method, and use two copies with an image coverage of 10% under normal temperature and normal humidity environment. An actual copy test of 30,000 copies was intermittently performed, and the image obtained on the 30,000th copy was visually evaluated. As a result, the photosensitive drum was not worn so much, the scraped amount was only 3.8 μm / 30,000 sheets, and the adhered matter began to adhere to the surface of the photosensitive drum. Further, since the cleaning blade did not have a cured layer formed thereon, the adhered matter was not scraped off well, filming occurred, and the cleaning blade curled up at about 150,000th sheet.

(Embodiment 2) The image forming apparatus of the 4-drum system is used, the binder resin forming the releasable layer IX of the photosensitive drum 1 is polyarylate, and the charging system is the roller. Adopts contact charging, at room temperature,
Under normal humidity environment, 2 copies with 10% image coverage are intermittently 3
An actual copy test of 10,000 copies was conducted, and the image obtained on the 30,000th copy was visually evaluated. The amount of abrasion of the photosensitive drum is 3.
Although the number of sheets was only 6 μm / 30,000 sheets, the cleaning blade used was one having an isocyanate compound impregnated and then cured by heating to form a cured layer. It was scraped off, and good cleaning was performed without deteriorating the slipperiness between the photosensitive drum and the blade.

(Comparative Example 2) As a comparison with Example 2, a cleaning blade used as the cleaning means is one in which a cured layer is formed by impregnating an isocyanate compound with the image forming apparatus of the four-drum type. In addition, a release layer of the photosensitive drum 1 is used, in which a cured layer is formed by coating nylon on at least a portion of the surface of a blade of thermosetting polyurethane having a JIS hardness of 70 degrees, which is in contact with the recording carrier, Using a binder resin made of polyarylate that forms IX,
Roller contact charging is adopted as the charging method. Under normal temperature and normal humidity environment, an actual coverage test of 30,000 copies with two copies with 10% image coverage is intermittently performed. It was evaluated visually. As a result, by forming a cured layer on the polyurethane cleaning blade with nylon, the adhered matter adhered to the surface of the photosensitive drum is scraped off,
Although the occurrence of fusion and filming was suppressed, the affinity with the surface of the photosensitive drum, which is peculiar to urethane, was not obtained like a blade impregnated with isocyanate and heat-cured. The toner slipped through the nylon coat blade.

(Embodiment 3) An XPS is used as the releasable layer IX of the photosensitive drum 1 by using the image forming apparatus of the 4-drum system.
Measured mole fraction ratio of carbon and fluorine atoms F / C
However, using F / C = 0.005%, the corona charging method is adopted as the charging means for charging the photosensitive drum, and the wire current is −200 μA and the grid voltage is −420 V.
Image application rate at room temperature and normal humidity while applying
The actual copy test of 30,000 copies was intermittently performed on two copies, and the image obtained on the 30,000th copy was visually evaluated. Since the corona charging method was used as the charging method, the abrasion amount of the photosensitive drum was only 3.6 μm / 30,000 sheets, but the cleaning blade was impregnated with an isocyanate compound and then cured by heating and curing. By using the layered product, the deposits generated on the surface of the photoconductor drum are scraped off, and the smoothness between the photoconductor drum and the blade is not deteriorated, and good cleaning is performed. It was

(Comparative Example 3) As a comparison with Example 3, the cleaning drum used as the cleaning means was not a hardened layer formed by using the image forming apparatus of the four-drum type, but a standard JIS hardness of 65. Of a thermosetting polyurethane of a certain degree, and the release layer of the photosensitive drum 1
As IX, a carbon atom-to-fluorine atom mol fraction ratio F / C measured by XPS of F / C = 0.005% is used, and the polymerized toner further contains calcium carbonate, and has a Mohs hardness of 3.0. Then, a corona charging method is used as a charging means for charging the photosensitive drum by performing image formation with a toner having a prescription in which abrasive particles having a volume-based average particle diameter of 1.0 μm are externally added at a ratio of 0.5 parts by weight. Adopting wire current -200μA and grid voltage -420V, under normal temperature and humidity environment, two copies with 10% image coverage were intermittently tested for 30,000 copies. The image obtained in 1. was visually evaluated. As a result, the adhered matter adhered to the surface of the photosensitive drum was polished and removed by the abrasive particles,
Since the abrasive particles have cut the photosensitive drum more than necessary, the cut portion cannot hold the electric potential given by charging, and image formation cannot be performed. An image defect has occurred.

(Embodiment 4) An XPS is used as the releasable layer IX of the photosensitive drum 1 by using the four-drum type image forming apparatus.
Measured mole fraction ratio of carbon and fluorine atoms F / C
However, using F / C = 0.07%, a roller contact charging system is adopted as the charging means for charging the photosensitive drum, and the cleaning blade used as the cleaning means is made of thermoplastic or thermosetting polyurethane. Becomes
A copy having an image coverage of 10% at room temperature and normal humidity was prepared by impregnating both ends of the blade with the photosensitive drum and impregnating the compound with an isocyanate compound and then heat curing to form a cured layer. An actual copy test of 30,000 copies was intermittently performed on two sheets, and the image obtained on the 30,000th copy was visually evaluated. Since both ends of the photosensitive drum are areas where an image is not directly formed and are not charged, the scraped amount is 3.3.
It reached only μm / 30,000 sheets. Therefore, although deposits started to be generated in the regions of both ends of the photosensitive drum, the deposits were scraped off by forming the hardened layer on the blade, and the slipperiness between the surface of the photosensitive drum and the blade was reduced. A good image was obtained without deterioration.

Comparative Example 4 As a comparison with Example 4, the quadruple-drum image forming apparatus was used, and as the releasable layer IX of the photosensitive drum 1, mols of carbon atoms and fluorine atoms measured by XPS were measured. A roller contact charging system is adopted as a charging means for charging the photosensitive drum, using a fraction ratio F / C of F / C = 0.07%, and the cleaning blade used as the cleaning means is an isocyanate compound. A hardened layer is not formed by impregnating with, but a part of both ends of the thermosetting polyurethane blade with JIS hardness of 65 degrees that is in contact with the photosensitive drum is coated with nylon. , Image coverage 1
An actual copy test of 30,000 copies was performed intermittently with two copies of 0%, and the image obtained on the 30,000th copy was visually evaluated.
As a result, by forming a hardened layer on the polyurethane cleaning blade with nylon, the adhered matter adhering to both ends of the photosensitive drum surface was scraped off, and the occurrence of fusing and filming was suppressed, but it was impregnated with isocyanate. Like the heat-cured blade, the affinity with the surface of the photosensitive drum peculiar to urethane was not obtained, and the toner slipped from both ends of the nylon-coated blade at the 20,000th sheet.

(Embodiment 5) Using the image forming apparatus of the 4-drum system, the image coverage is 10% under normal temperature and normal humidity environment.
Of 100,000 copies were intermittently made, and the image obtained on the 100,000th copy was visually evaluated.
The transfer belt cleaning device and the cleaning blade of the image carrier cleaning device were made of polyurethane, and the surface of the surface contacting with the recording medium was impregnated with an isocyanate compound and then heat-cured to form a cured layer. As a result, the 100,000th image was very good.

(Comparative Example 5) As a comparison with Example 5, a cleaning blade for cleaning the transfer belt using the image forming apparatus of the four-drum type is not usually cured by an isocyanate compound. By changing the blade of polyurethane material to JIS hardness 70 degrees, at room temperature and normal humidity, 100% copy of the image coverage of 10% was intermittently tested for 100,000 copies, and 100,000 copies were obtained. The obtained images were visually evaluated.
As a result, the slipperiness between the transfer belt and the cleaning blade of the belt deteriorated, and the blade was curled up after 40,000 sheets.

(Comparative Example 6) As a comparison with Example 5, the cleaning blade used for cleaning the recording image bearing member was not cured with an isocyanate compound using the image forming apparatus of the 4-drum type. By changing the blade to a JIS hardness of 65 degrees using ordinary polyurethane material, the image coverage rate is 10% under normal temperature and normal humidity environment.
Of 100,000 copies were intermittently made, and the image obtained on the 100,000th copy was visually evaluated.
As a result, the slipperiness between the image bearing member and the cleaning blade of the image bearing member deteriorated, and the curling of the blade occurred at the 60,000th sheet.

(Embodiment 6) Using the four-drum type image forming apparatus, the toner used is changed from the substantially spherical polymerized toner to the amorphous toner produced by a pulverization method, and the toner is used at room temperature at room temperature. In a damp environment, two 100% image coverage copies were intermittently tested for 100,000 copies, and 1
The images obtained on the 0,000th sheet were visually evaluated. Although the slipperiness between the cleaning blade and the carrier was a little worse than when using a substantially spherical toner, the cleaning blade of the transfer belt cleaning device and the image carrier cleaning device contacted the surface of the recording carrier. Since the blade is made of polyurethane in which a hardened layer is formed by impregnating a portion to be impregnated with an isocyanate compound, the deterioration of slipperiness is suppressed, and the blade is not rolled up. Image was very good.

(Comparative Example 7) As a comparison with Example 6, the toner to be used is changed from the substantially spherical polymerized toner to the irregular toner produced by a pulverization method using the image forming apparatus of the 4-drum system. Furthermore, the transfer belt cleaning device and the cleaning blade of the image bearing member cleaning device were changed from a blade impregnated with isocyanate and heat-cured to a blade formed by coating a conventional polyurethane blade with nylon at room temperature and under normal conditions. Under a moist environment, an actual copy test of 100,000 copies was intermittently performed with two copies having an image coverage of 10%, and the image obtained on the 100,000th copy was visually evaluated. As a result, with the nylon-coated blade, the slipperiness between the blade and the image bearing member could be secured, but the affinity with the image bearing member peculiar to urethane such as the blade impregnated with isocyanate and cured by heating has a good affinity. No toner was obtained, and the toner slipped from the nylon-coated blade at the 30,000th sheet.

Next, the cleaning device described in (9) and (10) above is a cleaning device for cleaning the surface of an intermediate transfer member to which an image is indirectly transferred from an image bearing member. The image forming apparatus according to the embodiment will be described. Example 7 below will be described using a color electrophotographic copying machine having an intermediate transfer member and having a counter blade system as a cleaning means for removing the transfer residue and the toner left on the surface thereof. FIG. 7 is a cross-sectional explanatory view showing the overall structure of the copying apparatus.

As an image forming apparatus having a transfer intermediate, an intermediate transfer belt 20 is arranged in contact with the photosensitive drum 1. The yellow toner adhering to the photosensitive drum 1 is applied to the photosensitive drum 1 by applying a positive DC bias to the primary transfer roller 22 arranged in contact with the portion of the back surface of the intermediate transfer belt 20 facing the photosensitive drum 1. Due to the electric field generated on the primary transfer roller 22, the negatively charged yellow toner on the photosensitive drum 1 is primarily transferred onto the intermediate transfer belt 20.

At this time, the transfer device toner remaining on the photosensitive drum 1 after the primary transfer member is removed by the cleaning blade 10 of the cleaning device 6.

The primary transfer roller 22 is composed of a metal core and an elastic body covering the core and having a low resistance (10 ⁵ Ω · cm or less). The intermediate transfer belt 20 is mainly made of a rubber material or a resin material. For example, there is a base layer made of rubber coated with a medium resistance surface layer. A metal core may be embedded in the rubber layer to prevent expansion and contraction. The intermediate transfer belt 20 is supported by three rollers, a drive roller 24, a secondary transfer counter roller 25, and a tension roller 23, so that an appropriate tension is maintained. By driving the drive roller 24, the intermediate transfer belt 20 rotates in the forward direction at substantially the same speed as the photosensitive drum 1.

After the primary transfer of the yellow toner onto the intermediate transfer belt 20, the rotary 21 rotates, and the magenta developing device 4b, the cyan developing device 4c, and the black developing device 4d are sequentially arranged at the positions facing the photosensitive drum 1, and the magenta toner,
The same operation is repeated for cyan toner and black toner, and four colors are superimposed on the intermediate transfer belt 20.

After that, the secondary transfer roller 2 is arranged with respect to the secondary transfer counter roller 25 with the intermediate transfer belt 20 interposed therebetween.
6 is brought into contact with the intermediate transfer belt 20, a bias having a polarity opposite to that of the toner is applied, and in this state, the transfer material P is passed between the intermediate transfer belt 20 and the secondary transfer roller 26, whereby the intermediate transfer belt The four color toners carried on 20 are collectively secondarily transferred to the transfer material P.

At this time, if there are differences in the charge amounts of the four color toners, the transferability for each color will be different. Depending on the case, the intermediate transfer belt 20 may be charged with a corona charger or the like before the secondary transfer.
The upper toner may be recharged so that the charge amounts of the toners of the respective colors are equalized. The secondary transfer roller 26 is
It consists of a metal core and an elastic body that covers it.

The transfer residual toner on the intermediate transfer belt 20 is
The cleaning blade 2 that is in contact with the intermediate transfer belt 20 in the counter direction with respect to the moving direction of the intermediate transfer belt 20.
Removed by 7.

The cleaning blade is an elastic blade mainly composed of urethane. After impregnating the portion of the blade surface which comes into contact with the intermediate transfer member with an isocyanate compound,
It was used after being cured by heating to form a cured layer. As a method for manufacturing the blade, a cleaning blade manufactured from urethane having a JIS JIS hardness of 70 manufactured from thermosetting polyester polyurethane is masked with a chemical resistant tape as shown in FIG. 2 and immersed in an MDI bath at 80 ° C. for 30 minutes, Wipe off excess isocyanate and remove the masking.
What was cured for 60 minutes in an oven at ℃ was used. The contact angle of the blade is 24 °, and the contact pressure is 33 (g / cm). The cleaning blade 27 has a plate thickness of 2 mm, and a SUS member (plate thickness 1.0) is arranged as a back plate. The free length of the cleaning blade is 10 mm
Is.

The transfer material P on which the toner image is transferred is conveyed to the fixing device 30 by the conveyor belt 29, the toner image and the transfer material P are heated and pressed, and the toner image is permanently fixed on the transfer material P and output. .

Further, a density detection sensor 28 is arranged adjacent to the surface of the photosensitive drum 1, and the control device (CPU) 13
Performs image density control based on the density information input from the density detection sensor 28. In addition, 11 is a temperature sensor mentioned above. The photosensitive drum 1, the charging roller 2, the exposure device 3, and the cleaning device 6 are integrated as a drum cartridge, and 12 is a storage device arranged in the drum cartridge. The storage device 12 uses (Non Volatile) RAM in the present embodiment. In the storage device 12,
Information that can clarify the usage status of the photosensitive drum 1, for example, the rotation time of the photosensitive drum 1, the time when the bias is applied to the charging roller 2, the exposure time of the exposure device 3, and the like are recorded.

In the above-described color image forming apparatus, since four colors of toner are superimposed to reproduce colors, if the image density changes due to various conditions such as changes in the environment of use and the number of prints, the original correct color tone can be obtained. I will not be able to.

Further, an excessive increase in the image density causes toner scattering due to an excessive amount of toner. On the toner image carrier such as the photosensitive drum 1, the intermediate transfer belt 20 or the transfer material P, the action of air pressure, electromagnetic force or the like exceeds the force of carrying the toner, and the toner image collapses. It is in a spread state. When the toner is scattered, the electrostatic latent image cannot be reproduced, and an image with a very bad appearance is output. In the color image forming apparatus, since four colors are overlaid, the toner easily scatters.

That is, in the color image forming apparatus, unlike the black-and-white image forming apparatus, a slight change in density is not allowed.

Therefore, in the present embodiment, the photosensitive drum 1
Toner images (patches) for density detection are formed on a trial basis, and their densities are detected by an optical density detection sensor 28 arranged adjacent to the photosensitive drum 1, and the controller 1
3 controls the image density by feeding back the image forming conditions such as the developing bias based on the density information input from the density detection sensor 28.

The density detecting sensor 28 is composed of an LED light emitting element and a photodiode light receiving element. Infrared light from the light emitting element is directed to the patch on the photosensitive drum 1 at an angle of 45 ° with respect to the photosensitive drum 1. The patch density is detected by irradiating the light at an angle and measuring diffused reflected light from the light-receiving element arranged so as to be perpendicular to the photosensitive drum 1.

Concentration detection sensor 2 due to scattering of developer, etc.
If 8 is dirty, the accuracy of density control is reduced, so the density detection sensor 28 is preferably arranged at a position where the influence of toner scattering is as small as possible. Specifically, as shown in FIG. 7, it is preferable to dispose the photosensitive drum 1 at a position exactly opposite to the developing device 4 with the photosensitive drum 1 interposed therebetween. The actual density control is preferably performed every 100 prints. In order to prevent the patch from being disturbed, a mechanism for separating the photosensitive drum 1 and the intermediate transfer belt 20 is provided so that the photosensitive drum 1 and the intermediate transfer belt 20 are separated from each other when the density control is executed. .

(Embodiment 7) As a means for cleaning the intermediate transfer member and the intermediate transfer member, a counter blade system is used, and the blade is made of thermoplastic or thermosetting polyurethane, and at least the recording surface of the blade is recorded. After the portion in contact with the carrier is impregnated with an isocyanate compound, it is heat-cured to form a cured layer, and an image forming apparatus using a blade is used. A 100,000-copy actual test was intermittently performed on two sheets, and the image obtained on the 100,000th sheet was visually evaluated. The slidability between the blade and the intermediate transfer member was good, and therefore the 100,000th image was also good.

(Comparative Example 8) As a means for cleaning the intermediate transfer member and the intermediate point transfer member, in an image forming apparatus having a counter blade system, the blade is a conventional polyurethane rubber blade and JIS hardness 73.
By using the blade of the degree, at normal temperature and normal humidity environment,
An actual copy test of 100,000 copies was intermittently performed with two copies having an image coverage of 10%, and the image obtained on the 100,000th copy was visually evaluated. As a result, a sufficient amount of transfer residual toner is not supplied to the cleaning blade of the intermediate transfer member, and therefore, the conventional blade cannot maintain the slipperiness of the intermediate transfer member and the chattering of the blade occurs at the 70,000th sheet. (Abnormal vibration) occurred.

[0073]

According to the present invention, an image forming apparatus in which the amount of wear on the surface of the image bearing member is remarkably reduced by taking advantage of a longer life, and
No image is formed, and the amount of wear is remarkably reduced because no charge is applied. Chattering (abnormal vibration) of the blade that tends to occur at both ends of the image bearing member, or curl without applying a lubricant to the blade. It is now possible to provide a new blade that can be reduced.

Further, according to the present invention, there are provided an image forming apparatus in which the amount of residual toner supplied to the cleaning device is small, and an image forming apparatus which uses toner which is difficult to impart slipperiness to the blade even when supplied to the cleaning device. It has become possible to provide a new blade that can reduce the chattering (abnormal vibration) and curling of the blade, which are likely to occur, without applying a lubricant to the blade.

Further, the blade is impregnated with an isocyanate compound and a part thereof is heated to form a hardened layer, which is a very inexpensive treatment method with which the accuracy of the blade edge straightness can be easily obtained. It has the advantage of being manufacturable.

The blade used in the present invention is different from a blade coated with nylon because it is made of thermoplastic and thermosetting polyurethane as a matrix and is impregnated with an isocyanate compound. Since the cured part also retains the properties of urethane rubber, the affinity with the carrier is maintained similarly to urethane rubber. Therefore, there is an effect that the toner does not easily slip through the blade.
In addition, as a result, the electrophotographic apparatus is provided with a cleaning device capable of greatly improving the reliability of the electrophotographic apparatus and capable of coping with the breakthrough in the productivity of the electrophotographic apparatus. It became possible to do.

[Brief description of drawings]

FIG. 1 is a schematic view of a four-drum type color electrophotographic copying apparatus having an image carrier cleaning unit according to the first, second, third, and fourth embodiments.

FIG. 2 is made of thermoplastic or thermosetting polyurethane,
It is a figure which shows the manufacturing method of the cleaning blade which impregnated the isocyanate compound into the surface at least the part which contacts a recording carrier, and hardened it by heating to form the hardened layer.

FIG. 3 is a cross-sectional view of an organic photosensitive drum used in a four-drum type color electrophotographic apparatus described in Examples 1, 2, 3, 4, 5, and 6.

FIG. 4 is a cleaning blade according to a fourth embodiment,
FIG. 3 is a schematic view of a blade made of thermoplastic or thermosetting polyurethane, in which both end portions of the blade, which come into contact with the photosensitive drum, are impregnated with an isocyanate compound and then cured by heating to form a cured layer.

FIG. 5 is a schematic diagram of a roller contact charging method described in Examples 1, 2, and 4.

FIG. 6 is a schematic diagram of the corona charging method described in the third embodiment.

FIG. 7 is an image forming apparatus according to one embodiment of the present invention, wherein the cleaning device is a cleaning device that cleans a surface of an intermediate transfer body to which an image is indirectly transferred from the image carrier. FIG. 3 is a schematic view of a color electrophotographic copying apparatus having a cleaning unit for removing the toner left on the surface of the intermediate transfer member.

[Explanation of symbols]

I Schematic diagram of cleaning blade with masking treatment II Schematic diagram of cleaning blade impregnated with isocyanate compound III Schematic diagram of blade after heat treatment of impregnated part IV Chemical resistant tape V Polyurethane cleaning blade VI Releasing layer VII Charge transporting layer VIII Charge generating layer IX Conductive substrate A Cleaning blade sandwiching sheet metal B Polyurethane cleaning blade C Curing layer formed by isocyanate compound D Contact charging roller E Photosensitive drum F External power supply

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/16 G03G 9/08 381 F term (reference) 2H005 AA15 AB03 2H030 AB02 AD03 BB24 BB46 BB71 2H068 AA03 AA04 AA06 BB25 BB27 BB31 BB40 FA03 FA04 FB11 FC15 2H134 GA01 GA05 GA06 GB02 GB08 HD01 HD19 HD20 KD08 KD16 KE01 KG07 KG08 KH15 KJ02 2H200 FA09 GA12 GA16 GA23 GA47 HA28 JA12 JC12 LB33 LB35 LC09 MA04

Claims (10)

[Claims] 1. A recording image carrier, a charging means for charging the image carrier, a recording material carrier for carrying and conveying a recording material, and a toner image formed on the recording material carried on the recording material carrier. Image forming means, a means for transferring the toner image to a transfer material, and a cleaning means for cleaning the recording material carrier, and the abrasion amount of the image carrier is 30,000. In a system in which the number of copies per sheet is less than 5 μm, the cleaning means is a counter blade type, the cleaning blade is made of thermoplastic or thermosetting polyurethane, and isocyanate is present on at least a portion of the blade surface which is in contact with the recording carrier. An image forming apparatus characterized by using a material in which a compound is impregnated and then cured by heating to form a cured layer. 2. A system in which the amount of abrasion of the image carrier is less than 5 μm per 30,000 copies of the image forming apparatus is an electron in which the image carrier has a surface layer containing at least carbon atoms and fluorine atoms. 2. A photographic photosensitive member, wherein the mole fraction ratio F / C of carbon atoms and fluorine atoms measured by XPS on the surface of the photosensitive member is F / C = 0.01 to 1.0. The image forming apparatus according to item 1. 3. A system in which the amount of abrasion of the image carrier is less than 5 μm per 30,000 copies of the image forming apparatus, the binder resin contained in the surface layer of the image carrier is polycarbonate, polyarylate or The image forming apparatus according to claim 1, wherein the image forming apparatus is one kind or a mixture of two or more kinds selected from polyallyl ether. 4. The image forming apparatus according to claim 1, wherein the charging unit that charges the image carrier is of a corona charging type. 5. A recording image carrier, a charging means for charging the image carrier, a recording material carrier for carrying and conveying a recording material, and a toner image formed on the recording material carried on the recording material carrier. In the image forming apparatus including an image forming unit for performing a toner image transfer onto a transfer material, and a cleaning unit for cleaning the recording material carrier, the cleaning unit is a counter blade type, and the cleaning blade is a thermal blade. An image formed of a plastic or thermosetting polyurethane, characterized in that a cured layer is formed by impregnating both ends of the blade in contact with the recording carrier with an isocyanate compound and then heat curing to form a cured layer. Forming equipment. 6. An image forming apparatus for forming an image by transferring a toner image carried by a carrier to a recording material, wherein an image carrier for directly or indirectly carrying the toner image and a conductive member are provided. The cleaning unit has a transfer unit for applying a transfer bias to transfer the toner image, and a unit for cleaning the residual toner on the surface of the carrier and the conductive member. In an image forming apparatus having a configuration in which the residual toner supplied to the recording medium is remarkably small, the cleaning blade is made of thermoplastic or thermosetting polyurethane, and at least a portion of the blade surface in contact with the recording carrier is impregnated with an isocyanate compound. An image forming apparatus comprising: a cured layer formed by being heated and cured. 7. The image forming apparatus that supplies a significantly small amount of residual toner to the cleaning means is a four-drum type full-color image forming apparatus.
The image forming apparatus according to item 1. 8. A cleaning device for supplying a significantly small amount of residual toner to the cleaning means is a cleaning device for cleaning the surface of a recording material carrying member carrying a recording material on which an image is transferred from the image carrying member. The image forming apparatus according to claim 6, wherein 9. A cleaning device for supplying a significantly small amount of residual toner to the cleaning means is a cleaning device for cleaning the surface of an intermediate transfer member to which an image is indirectly transferred from the image carrier. The image forming apparatus according to claim 6. 10. An image forming apparatus for transferring a toner image carried by a carrier to a recording material to form an image, comprising an image carrier for directly or indirectly carrying the toner image and a conductive member. It has a transfer means for applying a transfer bias to transfer the toner image, and a means for cleaning the residual toner on the surface of the carrier and the conductive member. In an image forming apparatus in which the toner to be formed is an irregular toner produced by a pulverization method, the cleaning blade is made of thermoplastic or thermosetting polyurethane, and an isocyanate compound is added to at least a portion of the blade surface which is in contact with the intermediate transfer member. An image forming apparatus characterized in that it is impregnated and then cured by heating to form a cured layer.