JPH1138791A - Image-recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a toner contamination of a sub-system by an excessive toner which is not transferred to a recording medium at the time of occurrence of a jam or after occurrence of the jam, and to thereby provide an image- recording device having high-quality images. SOLUTION: In this image-recording device, by which toner images formed on plural photosensitive drums, 1Y, 1M, 1C and 1K, are primarily transcribed on an intermediate transfer belt 5, and the toner-images are secondarily transferred on a recording medium 11, a particle-imparting means 10, by which particles, the average particle size of which is smaller than the toner, are supplied to the intermediate transfer belt 5, is installed. At the time of occurrence of a jam, after removing the recording medium under conveyance, if necessary, the toner images formed on the photoreceptor drums, 1Y, 1M, 1C and 1K, are transferred on the intermediate transfer belt 5 provided with the particles, under the control of a control means, without supplying the recording medium, and an electric potential, having a reverse polarity to a charged polarity of the toner, is applied, and then, the toner pictures are recovered by the particle- imparting means 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an indirect transfer type image recording apparatus for forming a toner image using an electrostatic latent image, and more particularly, to transferring a toner image formed on a photosensitive member to an intermediate transfer member. And an electrophotographic image recording apparatus for transferring a toner image from the intermediate transfer member to a recording medium.

[0002]

2. Description of the Related Art In an electrophotographic image recording apparatus using an intermediate transfer member, a charging step for uniformly charging the surface of a latent image carrier, and exposing the charged surface of the latent image carrier according to an image. Exposure step of forming an electrostatic latent image by performing, a developing step of attaching a toner to the electrostatic latent image to form a toner image, a primary transfer step of transferring the toner image to an intermediate transfer body,
A secondary transfer step of transferring the toner image from the intermediate transfer member to the recording medium, a fixing step of fixing the toner image on the recording medium, and the latent image carrier remaining on the latent image carrier and the intermediate transfer body in the primary and secondary transfer steps An image is formed by a cleaning process for removing the toner. After the cleaning step, a charge removing step for electrically initializing the surface of the latent image carrier is provided as necessary.

FIG. 8 shows a schematic configuration of a conventional color image forming apparatus using an intermediate transfer member disclosed in Japanese Patent Application Laid-Open No. 9-6146. In this color image forming apparatus, a photoconductor 101 is used as an image carrier,
01 is charged to the desired initial charging potential V _H by scorotron 102, by irradiating the exposure light 104 according to an image signal from the exposure unit 103, the image portion potential on the photosensitive member 101 is V _L, the non-image portion potential the electrostatic latent image of a substantially V _H is formed. Then, the developing means 105 corresponding to the desired color
V _L is an image portion by the developing device 105a~105d
After the toner image is formed on the portion, the bias roller 1 is attached to the back surface of the intermediate transfer belt 106 having the peripheral length corresponding to the maximum recording length.
In step 07, a charge having a polarity opposite to that of the toner image is given, and the toner image on the photoconductor is primarily transferred onto the intermediate transfer belt 106.

[0004] The photosensitive member 1 is not transferred in the primary transfer step.
The toner remaining on the toner image 01 is removed by the cleaning unit 108, the photosensitive member 101 is electrically initialized by the charge eliminating lamp 109, and the recording cycle of the next recording color is continued. In this color image forming apparatus, the above-described recording is repeated in the order of yellow, magenta, cyan, and black, and primary transfer to the intermediate transfer belt 106 is repeated, so that a color toner image is formed on the intermediate transfer belt 106. Finally, the recording paper 111 is conveyed to a region sandwiched between the intermediate transfer belt 106 and the bias roller 110, and the color toner image on the intermediate transfer belt is secondarily transferred onto the recording paper 111.

Then, the recording paper 111 is passed through a fixing device 112 to fix the toner image thereon, thereby forming a final color image. Then, the intermediate belt 106 after the secondary transfer is cleaned by the cleaning blade 113. Here, the cleaning blade 113 is brought into contact with the intermediate transfer belt 106 only during cleaning,
It is driven so as to approach and separate from the intermediate transfer belt 106.

In the above-described color image forming apparatus, four colors of one image are superimposed on the intermediate transfer belt 106.
As described above, the circumference of the intermediate transfer belt 106 needs to be equal to or larger than the size of the recorded image, and there is a problem that the apparatus cannot be downsized. Further, the cleaning blade 113 is separated from the intermediate transfer belt 106 during recording of four colors (four cycles) on the intermediate transfer belt 106, and when cleaning at the end of recording or when a jam such as a paper jam occurs, It is necessary to provide a mechanism for bringing the cleaning blade 113 into contact with the intermediate transfer belt 106, and there is a problem that the apparatus becomes complicated.

Here, with respect to cleaning of the photosensitive member and the intermediate transfer member at the time of a paper jam, conventionally, Japanese Patent Laid-Open No. 6-954 has been disclosed.
An image recording apparatus disclosed in Japanese Patent Publication No. 47 is proposed.
When a paper jam occurs, the apparatus transfers all toner images already formed on the photoreceptor to the intermediate transfer member, and then stops the apparatus.When the apparatus is restarted, the intermediate transfer body cleaner is activated. In this case, the intermediate transfer member is cleaned by performing sheet transfer. However, in such an image recording apparatus, the intermediate transfer body cleaner needs to be separated from the intermediate transfer body during normal recording, and the paper passed for removing excess toner is discarded as waste. turn into. Therefore, there has been a problem that the apparatus is complicated and waste paper is generated.

On the other hand, there is known an image recording apparatus which forms images on a plurality of photoconductors, sequentially performs primary transfer on an intermediate transfer body, and continuously performs secondary transfer on a recording medium in order to reduce the size of the apparatus. . Further, an image recording apparatus combined with a cleanerless system has been known as a recent environmentally friendly technology because of a requirement of eliminating waste toner. As a cleaner-less image recording apparatus, Japanese Patent Application Laid-Open No. 2-51168 discloses a cleaner-less development recording apparatus of a simultaneous development and cleaning type in which a developing unit also has a cleaner function.

Any of these methods can be combined with an intermediate transfer member, and FIG. 9 schematically shows a cleanerless image recording apparatus using the intermediate transfer member. Multiple photoconductors 1 corresponding to yellow, magenta, cyan, and black
20Y, 120M, 120C, and 120K, each of which forms an electrostatic latent image, and a developing device 121Y, 121M,
Develop at 121C and 121K. The developed toner images are transferred to transfer rollers 123Y, 123M, 123C, 123
K, the transfer bias voltage applied to the intermediate transfer body 1
24. In this transfer step, each color is simultaneously performed, and the color superimposed images sequentially formed on the intermediate transfer body 124 are simultaneously transferred to the recording medium 12 at the downstream portion thereof at the same time as the primary transfer.
5 is secondarily transferred.

Here, since this apparatus is a cleanerless system, if primary transfer is not completely performed when a jam occurs, a contact charger 126 such as a film charger in contact with the photosensitive member is transferred to the intermediate transfer member 124. It is contaminated by excess toner on the photoreceptor that has not been transferred. Further, the intermediate transfer body 12
4 is in contact with the recording medium 1.
27 is contaminated by excess toner on the intermediate transfer body 124 that has not been secondarily transferred. The toner contamination (contamination) of the subsystem due to the jam has a problem that image quality defects such as uneven density due to charging failure and back stain on a recording medium are caused in image recording after the jam.

[0011] Under such circumstances, Japanese Patent Application Laid-Open No. 9-61 is disclosed.
Even if the method described in JP-A-46-46 is adopted, there is a problem that the cleaning efficiency of the blade type cleaner is inferior to that of the small particle size toner and the spherical toner excellent in cleanerless suitability, resulting in poor cleaning. Further, when controlling the contact and separation of the cleaner, the mechanism becomes complicated as described above, and if the blade cleaner is constantly pressed without providing such a mechanism, the generation of scratches on the surface of the intermediate transfer member or the like There has been a problem that wear is caused and the life of the intermediate transfer member is shortened.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and primary-transfers toner images formed on a plurality of image carriers to an intermediate transfer member, and records the toner images. An image recording apparatus that performs secondary transfer to a medium is to provide a high-quality image recording apparatus that prevents toner contamination of a subsystem due to excess toner not transferred to a recording medium when a jam occurs or after a jam occurs. . Further, the toner images formed on the plurality of image carriers are primarily transferred to a smaller number of primary intermediate transfer members than the image carriers, and the toner images on the plurality of primary intermediate transfer members are transferred to the secondary intermediate transfer member. In an image recording apparatus that performs the next transfer and the tertiary transfer of the toner image to a recording medium, it is possible to prevent toner contamination of the subsystem due to excess toner not transferred to the recording medium at the time of the occurrence of the jam or after the occurrence of the jam, thereby achieving high quality It is intended to provide a recording device. It is a further object of the present invention to provide a compact and highly reliable image recording apparatus which is compatible with a recent environment-friendly requirement and which is both cleaner and toner-free in the event of a paper jam.

[0013]

The first object of the present invention is to provide an image recording apparatus wherein a toner image formed on a plurality of image carriers is primarily transferred to an intermediate transfer member, and the toner image is secondarily transferred to a recording medium. In the apparatus, a fine particle applying means for supplying fine particles having a smaller average particle diameter than the toner to the intermediate transfer body is provided, and when a jam occurs, the recording medium being conveyed is removed as necessary, and under control by the control means, The toner image formed on the image bearing member is transferred to the intermediate transfer member provided with the fine particles without supplying the recording medium, and a potential having a polarity opposite to the charging polarity of the toner is applied to convert the toner image into the fine particles. Achieved by collecting with an application means.

A second object of the present invention is to primarily transfer a toner image formed on a plurality of image carriers to a smaller number of primary intermediate transfer members than the image carriers, and to transfer the toner images onto the plurality of primary intermediate transfer members. In an image recording apparatus for secondary-transferring the toner image to another secondary intermediate transfer member and tertiary-transferring the toner image to a recording medium, fine particles supplying fine particles having an average particle diameter smaller than the toner to the secondary intermediate transfer member After the recording medium being conveyed is removed as necessary when a jam occurs, the recording medium is formed on the image carrier or the primary intermediate transfer body without supplying the recording medium under the control of the control means. The transferred toner image is transferred to a secondary intermediate transfer body provided with fine particles,
This is achieved by applying a potential having a polarity opposite to the charging polarity of the toner and collecting the toner image by the fine particle applying means.

Further, preferably, the distance between the fine particle applying means and the most upstream transfer position on the intermediate transfer member with which the fine particle applying means abuts is such that the image carrier is restarted after the jam and the first intermediate transfer member is moved to the intermediate transfer member. It is desirable that the distance is shorter than the distance the intermediate transfer member moves until the toner image is transferred to the intermediate transfer member. Thereby, the supply of the fine particles is performed within a short time, and a high operation rate can be realized.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a configuration of a so-called tandem type color image recording apparatus according to a first embodiment of the present invention. This color image recording apparatus includes photosensitive drums 1Y, 1M, 1C, and 1K for each of yellow, magenta, cyan, and black,
Around it, a dedicated laser beam scanner 3Y,
3M, 3C, 3K, chargers 2Y, 2M, 2C, 2K, and developing units 4Y, 4M, 4C, 4K are arranged. The intermediate transfer belt 5 is in contact with the photosensitive drum at the toner image transfer position of each photosensitive drum, and is stretched by the transfer rollers 6Y, 6M, 6C, 6K and the backup rollers 12, 13 so that the primary transfer is performed. Transfer roller 6
Y, 6M, 6C and 6K each have a primary transfer bias power supply 7
Y, 7M, 7C, and 7K are connected, and are set so that the same voltage or the downstream voltage is slightly higher than the upstream voltage.

The intermediate transfer belt 5 has a volume resistivity of 10 ⁷ to 10 ¹⁴ Ωcm by mixing a resistance controlling agent such as carbon black into porimide, polyvinylidene fluoride, polyethylene terephthalate or polycarbonate.
It was made to become. Thickness is 50 from mechanical strength requirement.
Use one with a thickness of at least μm. The toner image formed on the intermediate transfer belt 5 is secondarily transferred onto the recording medium 11 by a secondary transfer roller 8 to which a secondary transfer bias power supply 9 is connected, and is fixed by a fixing device (not shown). Will be On the other hand, the process direction P of the secondary transfer position of the intermediate transfer belt 5
On the downstream side of the device, means 1 for applying fine particles to the intermediate transfer belt 5
0 is provided.

Next, the operation of the color image recording apparatus when a jam occurs will be described in detail with reference to a timing chart. FIG. 2 is a timing chart showing the driving status of each subsystem when a jam occurs and when the driving is restarted thereafter. This timing chart shows control signals when controlling each subsystem by a control device such as a central processing unit provided in the color image recording apparatus. Further, since the most frequent jam is a conveyance failure of a recording medium (so-called paper jam), a case where a paper jam occurs during image recording will be described as an example.

A paper jam during the image recording operation is detected by a photoelectric switch or the like provided on the recording medium conveyance path, and a jam detection signal S is output simultaneously with the occurrence of the jam. Upon receiving the detection signal S, the controller sets the recording apparatus to the jam occurrence mode J1, and in the present embodiment, temporarily turns off all the driving units. Next, a message is output to inform the operator of the occurrence of a paper jam in order to urge the operator to remove the jammed recording paper, and according to the instruction, the jammed recording paper is removed from the inside of the apparatus by, for example, closing the cover of the apparatus body. Then, the jam release signal R for restarting the device is output, and the jam recovery mode J2
to go into.

The jam recovery mode J2 is a process for mainly cleaning the toner image remaining on the photoreceptor and the intermediate transfer member. More specifically, the image exposure is not performed and the secondary transfer roller The point that the bias voltage applied to the secondary transfer roller 8 in order to prevent the transfer of the toner image to the secondary transfer roller 8 has a polarity (power supply 9B in FIG. 1) opposite to that of the normal transfer (power supply 9A in FIG. 1). Except for this, it is almost the same as the image forming process. Therefore, the toner image to be cleaned is the intermediate transfer belt 5
At this time, the toner image is formed by applying fine particles and applying a potential having a polarity opposite to that of the toner by the fine particle supply means 10 in contact with the intermediate transfer belt 5 according to the timing chart of FIG. Clean and collect.

The fine particles applied to the intermediate transfer belt 5 by the fine particle supply means 10 are specifically titanium oxide,
Inorganic fine powders such as alumina, silica, barium titanate, calcium titanate, strontium titanate, zinc oxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride, chromium oxide, and red iron oxide , Polyacrylate,
Organic fine powders such as polymethacrylate, polymethyl methacrylate, polyethylene, polypropylene, polyvinylidene fluoride, polytetrafluoroethylene and the like can be mentioned. In consideration of environmental stability, it is desirable that these fine particles have a low hygroscopic property. In particular, in the case of an inorganic fine powder having a hygroscopic property such as titanium oxide, alumina, and silica, those subjected to a hydrophobic treatment are used. . Hydrophobic treatment of these inorganic fine powders, for example, dialkyl halogenated silane, trialkyl halogenated silane, silane coupling agent such as alkyl trihalogenated silane or hydrophobic treatment agent such as dimethyl silicon oil and the fine powder and The reaction can be performed at a high temperature.

As the fine particle applying means 10, there is a magnetic brush method formed by mixing the above fine particles with magnetic carrier particles. The requirements for the application of the fine particles are not limited to the magnetic brush method as long as the secondary particles of the fine particles are loosened and uniformly adhered to the intermediate transfer belt 5. In addition, the force applied to the intermediate transfer belt 5 varies depending on the volume resistivity of the fine particles used.
Since the average particle diameter is about several tens of nanometers, the adhesion to the intermediate transfer member 5 is dominated by Van der Waals force, and can be attached by contact.

When the excess toner on the intermediate transfer belt 5 is cleaned by the fine particle applying means 10, a potential opposite to the charging polarity of the toner is applied to the sleeve electrode forming the magnetic brush by the control of the control device. Apply. As a result, the excess toner is magnetically attached to the particle applying means 10 and collected, and the intermediate transfer belt 5 is cleaned.
The surplus toner collected by the fine particle applying means 10 is
The polarity is opposite to the polarity of the bias potential at the time of cleaning due to frictional charging with the carrier. Normally, a potential having the same polarity as that of cleaning is applied to prevent retransfer to the intermediate transfer belt 5.

Main specifications of the color image recording apparatus according to the first embodiment shown in FIG. 1 are shown below.

(Exposure units 3Y, 3M, 3C, 3
K): 600 dpi LD ROS, emission wavelength 780n
m.

(Exposure (gradation) control method): input 8 bi
t, analog screen method using both 200 lines and 400 lines by exposure pulse width modulation, 100% exposure potential V _L = -100V.

(Photoconductors 1Y, 1M, 1C, 1K): FIG.
(2) A function-separated type photoconductor 40 in which a pull-down layer 42 is formed on a conductive support 41 as necessary, and a charge generation layer 43 and a charge transport layer 44 are sequentially laminated. Conductive support 4
1 is a metal drum and sheet of aluminum, copper, stainless steel or the like, a plastic film, a laminate of a metal foil of aluminum or the like on paper or the like, or a material obtained by vapor-depositing aluminum or metal, and a metal or resin. And a resin drum on which a resin layer in which conductive particles are dispersed is applied. If necessary, the surface of the conductive support 41 may be subjected to a roughening treatment for preventing interference fringes. In this example, a stainless steel pipe having an outer diameter of 15 mm and a thickness of 1 mm was used.

The undercoat layer 42 is provided as necessary to improve the adhesion between the conductive support 41 and the charge generation layer 43 and to prevent coating defects of the charge generation layer 43. Subbing layer 42
As a material for forming, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl methyl ether, polyamide, thermoplastic polyester,
Phenoxy resin, casein gelatin, thermoplastic resin such as nitrocellulose, polyimide, polyethyleneimine,
Thermosetting resin such as epoxy resin, melamine resin, phenol resin, polyurethane resin, titanium coupling agent,
Organic metal compounds such as a zirconium coupling agent and a silane coupling agent are known. These materials are
They can be used alone or in combination of two or more. The undercoat layer 42 is formed by dissolving and mixing the above materials with a solvent as necessary, diluting the mixture, applying the mixture on the conductive support 41 by spray coating, dip coating, and the like. It is performed by drying in a temperature range of 200 ° C. The thickness of the undercoat layer 41 is arbitrarily set in the range of 0.1 to 10 μm, but is particularly preferably 0.1 μm for ease of manufacture.
A range of 5 to 2 μm is preferred.

The charge generation layer 43 is formed by dissolving a binder resin in a solvent, dispersing a charge generation material therein, and applying a spray coating method.
After being applied by a dip coating method or the like, a dried product or a product obtained by directly depositing a charge generation material by a vacuum deposition method or the like is used. As the charge generating material, for example, azo dyes such as chlorodian blue, anthantrone, oxine pigments such as pyrenequinone, quinocyanine pigments, perylene pigments, indigo pigments, bisbenzimidazole pigments, metal-free phthalocyanines, copper phthalocyanines, vanadyl phthalocyanines, titanyl phthalocyanines And phthalocyanine pigments such as gallium phthalocyanine, azurenium salts, squarylium pigments, and quinacridone pigments. Examples of the binder resin include polyvinyl butyral, polyarylate (a polymer of bisphenol A and phthalic acid),
Polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, acrylic resin, polyacrylamide, polyamide resin, polyvinyl pyridine, cellulose resin, urethane resin, epoxy resin casein, polyvinyl alcohol,
An insulating resin such as polyvinylpyrrolidone can be used. The thickness of the charge generation layer 43 is arbitrarily set in the range of 0.01 to 5 μm, but is preferably 0.1
０．５0.5 μm.

The charge transport layer 44 is formed by applying a binder resin to a solvent, applying a solution obtained by adding a charge transport agent to the solvent by a spray coating method, a dip coating method, and the like, followed by drying. You. The charge transport agent is a polycyclic aromatic compound such as anthracene, pyrene, phenanthrene, or
Compounds having a nitrogen-containing heterocycle such as indole, carbazole, imidazole, and the like, pyrazoline compounds, hydrazone compounds, triphenylmethane compounds, triarylamine compounds, enamine compounds, stilbene compounds, and the like can be used. Examples of the binder resin used for the charge transport layer 44 include a polycarbonate resin, a polyester resin, a methacrylic resin, an acrylic resin, a polyvinyl chloride resin, a polyvinylidene chloride resin, a polystyrene resin, a polyvinyl acetate resin, a styrene-butadiene copolymer, and a chloride resin. Vinylidene-acrylonitrile copolymer, vinyl chloride-
Known resins such as vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinylcarbazole, and polysilane Can be used, but the present invention is not limited to these. The thickness of the charge transport layer 44 is arbitrarily set in the range of 1 to 40 μm, but is preferably 5 to 30 μm from the viewpoint of uneven coating or generation of pin poles at the time of preparation and photodischarge characteristics, that is, charge transfer speed.

(Chargers 2Y, 2M, 2C, 2K): BC
R, brushes, magnetic brushes, film chargers, and other devices utilizing discharge in a minute gap with a photoreceptor are used. FIG. 5 shows the charging device used in this example. An electrode supporting member 51 for supplying power to the charging electrode 52 while maintaining the shape of the charging electrode 52 in the shape of a circular belt, and a pressing member 53 for pressing the charging electrode 52 against the electrode supporting member 51 to assist power supply and shape retention. The photosensitive drum 1 is charged by bringing the charging electrode 52 into contact with the photosensitive drum 1.

As the charging electrode 52, any electrode having semiconductivity may be used, for example, polyester, polyamide, polyethylene, polycarbonate, and the like.
Polyolefin, polyurethane, polyvinylidene fluoride, polyimide, PEN, PEK, PES, PPS, P
FA, PVdF, ETFE, CTFE, etc., or synthetic rubber such as silicon rubber, ethylene propylene rubber, butyl rubber, acrylic rubber, urethane rubber, nitrile rubber mixed with conductive powder such as carbon black or metal powder Can be used. Further, a polar rubber such as epichlorohydrin rubber, chloroprene rubber, EPDM rubber, or a semiconductive inorganic material such as amorphous silicon may be formed by vapor-depositing a thin film or a thick film on an insulating substrate. However, since a polar rubber or the like has a high adhesive force, it is necessary to devise a method of coating the surface with a low-adhesion material or the like. Further, when a thin film or a thick film is deposited, the hardness is large, so that it is preferable to dispose the film in a non-contact manner with respect to the charge acceptor. At this time, it is necessary to adjust the amount of the conductive particles to be mixed so as to obtain a preferable volume resistivity. Spark discharge is liable to be generated at 10 ² Ω · cm or less, and dot-shaped charge failure is caused at 10 ¹¹ Ω · cm or more. Therefore, it is desirable to use in the range of 10 ³ Ω · cm to ^{10 10} Ω · cm. In particular, 10 ³ Ω · cm to 10 ⁶ Ω
In cm, since the charging voltage applied to the charger can be set relatively low, when using a high-speed machine with a process speed of 150 mm / sec or more,
This is most preferable because potential fluctuation can be reduced.

The charging voltage applied to the charging electrode 52 can be either a DC voltage (not shown) or a voltage obtained by superimposing an AC voltage that is twice or more the charging start voltage on the DC voltage. It is desirable to use a DC voltage because a voltage with a superimposed voltage increases the surface energy of the surface of the charge acceptor and the charging device, and further adversely affects the charge acceptor. The outer shape of the film tube 52 is φ10 mm, and the applied voltage of the film is 1 kV.
(Charging voltage V _H = −450 V).

(Developer): Dry two-component developer (spherical toner having an average particle diameter of 7 μm by a spherical carrier and a solution suspension method).

(Developing units 4Y, 4M, 4C, 4K): The developing device shown in FIG. 6 which has been already proposed by the present applicant in Japanese Patent Application No. 8-40380. FIG. 7 shows a schematic configuration of a developer carrier used in the developing device. In the developing device shown in FIG. 6, an opening for development is provided in a portion of the developing housing 62 in which the developer is accommodated, facing the photosensitive drum 1, and the developing roll 61 is disposed in this opening. Two screw augers 64 and 65 are provided on the side. Further, a scraper 63 for removing the developer adhered on the developing roll 61 is provided so as to come into contact with the developing roll 61. The screw augers 64 and 65 are provided in two developer stirring / transfer chambers partitioned by a partition wall 66 in the developing housing 62, and are driven to rotate so as to transport the developer in opposite directions. The two developer stirring / transfer chambers communicate at both ends, and the developer conveyed by the screw augers 64 and 65 circulates and moves in the two developer stirring / transfer chambers while being stirred.

As shown in FIG. 7, the developing roll 61 has a cylindrical conductive base 61a supported so as to be rotatable around an axis, and a magnetic recording layer 61b formed on the peripheral surface thereof. The main part is constituted by. The developing roll 61 has a certain gap with the photosensitive drum 1, and is held so that the developer layer is not in contact with the photosensitive drum 1.

The magnetic recording layer 61b is formed by dispersing a ferromagnetic material in a binder resin. As the magnetic material, any material known as a magnet material or a magnetic recording material can be used. For example, γ-Fe ₂ O ₃ or CrO ₂
Etc. can be used. Further, as the binder material, any material known as a resin constituting a magnetic recording material such as a tape, a disk or a card can be used, and for example, polycarbonate, polyester, polyurethane and the like can be used. Further, conductive fine particles and the like can be added to the magnetic recording layer 61b as needed.

On the other hand, as an improvement, a developer carrier provided with a plurality of magnetic poles for adsorbing a two-component developer containing a toner and a magnetic carrier substantially uniformly on the peripheral surface is spaced apart from each other. A developing device that transports the two-component developer by rotating the developer carrier including the developer carrier, applies a developing bias voltage to the developer carrier, and develops an electrostatic latent image on the image carrier with toner. The magnetic poles are arranged in a substantially constant pattern, and the substantially constant pattern includes a pair of adjacent north and south poles and a low magnetic force region or a non-magnetized region provided outside the pair of magnetic poles. Wherein the distance between the pair of adjacent N-poles and S-poles on the peripheral surface of the developer carrier is 25 μm or more and 250 μm or more.
μm or less, and the distance between adjacent magnetic poles across the low magnetic force region or the non-magnetized region is 300 μm or less. Note that, for example, the magnetic poles adjacent to each other with the low magnetic force region or the non-magnetized region interposed therebetween are set to be magnetic poles having different polarities. Further, for example, the magnetic poles adjacent to each other with the low magnetic force region or the non-magnetized region interposed therebetween are set to have the same polarity.

In this developing device, the developer carrier holds a certain amount of developer in a thin layer by the above-mentioned minute gap magnetization and the low magnetic force effect, and the developer carrier itself having a magnetic force rotates. Since the developer is transported, and the magnetic tumbling which is used in the developer transport including the magnetic roll and the developing sleeve is not used unlike the related art, the toner amount to be developed is saturated. As a result, the development gamma (the slope of the curve representing the relationship between the development potential and the development superimposition) tends to be higher than that of the conventional developing device, and the development characteristics in which the development superimposition is saturated in a region where the development contrast potential is relatively low. Become. In this example, a magnetic roll having a diameter of 8 mm was used.

(Transfer): Belt intermediate transfer member system. Primary transfer voltage 0.4 to 0.8 kV (constant voltage). Primary transfer nip load 300 to 600 g. Secondary transfer voltage 1 to 1.5 kV.
Secondary transfer nip load 0.5 to 2 kg.

(Intermediate transfer member 5): A resistance controlling agent such as carbon black is mixed into polyimide, polyvinylidene fluoride, polyethylene terephthalate or polycarbonate so that the volume resistivity becomes 10 ⁷ to 10 ¹⁴ Ω · cm. . If the volume resistivity is too low, the current flowing through the power supply at the time of transfer becomes large, and a transfer power supply having a large power supply capacity is required. On the other hand, if the volume resistivity is too high, the belt cannot be neutralized by itself, and a neutralizer for the intermediate transfer member is required separately. Therefore, the volume resistivity is preferably 10 ⁸ to 10 ¹²
In this example, an intermediate transfer belt having a volume resistivity of 10 ¹² Ω · cm by dispersing carbon particles in a polyimide film was used. The belt had a thickness of 50 μm or more from the viewpoint of mechanical strength.

(Particle applying device 10): a developing sleeve having an outer diameter of 10 mm (incorporating eight magnetic pole rolls). A magnetic brush is formed with a magnetic carrier having a trimmer gap of 0.3 to 1 mm and an average particle size of 30 to 50 μm. The basic configuration may be the same as that of a conventional two-component developing device. As the fine particles mixed with the magnetic carrier, titanium oxide particles having an average particle size of 10 to 30 nm were used. Further, when used as a cleaner or when excess toner is mixed with the carrier, a bias voltage is applied to the developing sleeve as necessary. Specifically, when the excess toner at the time of the jam has a negative polarity, +1 to 1 k
A voltage is applied in the range of V.

(Fixing device): Roller fixing device, fixing temperature 15
5 ° C.

(Others): Process speed P = 100 mm
/ S.

When an image was printed under the above conditions, a good transfer rate and a high quality image could be obtained. Even when a jam occurs, the excess toner on the photosensitive drum and the intermediate transfer belt is finally collected by the fine particle applying means 10 provided on the outer periphery of the intermediate transfer belt based on the sequence described in FIG. In addition, it was possible to form an image free of stains.

The distance between the installation position of the fine particle applying means 10 and the most upstream transfer position (the position of the photosensitive drum 1Y in FIG. 1) on the intermediate transfer belt to which the fine particle applying means 10 is attached is determined by the distance of the photosensitive member. The distance from the movement of the intermediate transfer belt to the time when the drum is driven and the toner image is first transferred to the intermediate transfer belt is shorter than before the toner image is transferred from the photosensitive drum to the intermediate transfer belt. Fine particles can be attached to the transfer area of the intermediate transfer belt. Therefore, the toner image can be transferred with the fine particle layer interposed on the intermediate transfer belt without providing a special operation time when a jam occurs, and the recovery and cleaning of the excess toner can be quickly and reliably performed. Can be.

FIG. 3 shows the configuration of a color image recording apparatus according to a second embodiment of the present invention. The same parts as those in the first embodiment described above are denoted by the same reference numerals, and redundant description will be omitted. This color image recording apparatus includes two primary intermediate transfer drums 35 instead of the intermediate transfer belt 5.
a, 35b and one secondary intermediate transfer drum 36. The toner images are transferred from the photosensitive drums 1Y and 1K to the primary intermediate transfer drum 35a, and the toner images are transferred from the photosensitive drums 1C and 1M to the primary intermediate transfer drum 35b.
b is transferred to the secondary intermediate transfer drum 36,
Finally, the toner image formed on the secondary intermediate transfer drum 36 is tertiarily transferred onto the recording medium 11 by the transfer roller 37.

Also in the color image recording apparatus of the present embodiment, the fine particles supplied from the fine particle applying means 10 are used for the secondary intermediate transfer drum 36 and the primary intermediate transfer drum 3.
The surplus toner formed on the intermediate transfer drum is quickly and reliably collected and cleaned by the fine particle applying means 10 in the case where the toner adheres to the intermediate transfer drums 5a and 35b and a jam occurs.

The main specifications of the color image recording apparatus according to the second embodiment shown in FIG. 3 are shown below. The configuration other than the following specifications was the same as the first embodiment.

(Transfer): Intermediate transfer drum system. Primary transfer voltage 0.5-1 kV. Primary transfer nip load 200 to 50
0 g. Secondary transfer voltage 1-2 kV. Secondary transfer nip load 5
00-1000 g.

(Intermediate transfer member): Primary intermediate transfer drum 35
a and 35b are φ42 mm, and the secondary intermediate transfer drum 36 is φ42 mm.
42 mm. The surface material and thickness are the same as in the first embodiment.
A conductive sponge layer of 10 ⁵ Ω · cm or less was provided as a lower layer. Here, as a combination of the primary and secondary intermediate transfer drums, if the hardness is a combination of the photosensitive drum> the primary intermediate transfer drum <the secondary intermediate transfer drum> the recording medium (paper), higher transfer efficiency is obtained. can get.

(Particle providing means 10): The basic structure is the first
Same as the embodiment. Here, the fine particle applying means is installed on the secondary intermediate transfer drum 36. However, when the fine particles are supplied to the secondary intermediate transfer drum 36 to some extent, a part of the fine particles is transferred to the primary intermediate transfer drums 35a and 35b, It is possible to also serve to impart fine particles to the intermediate transfer drums 35a and 35b.

(Deposition of Fine Particles on Photoconductor): Fine particles can be deposited on the photosensitive drums 1Y, 1M, 1C, and 1K, which are image carriers, by a mechanical method or an electrical method. Any method may be used as long as the fine particles can be adhered onto the image carrier, such as a method using both of them, and the like. As a method of mechanically attaching, there is a method by rubbing, and as such a method, for example, a method of rubbing with a roll, brush, felt, web, or brush is mentioned. As a roll,
Rigid rolls formed of a rigid body such as metal or hard plastic, and elastic rolls using a material having elasticity such as rubber, the pressure in the rubbing nip,
Elastic rolls are easier to use because of the ease of adjusting the nip width. Specific examples of the brush include a magnetic brush using magnetism and a fur brush. By applying electrolysis in addition to such a mechanical attachment method, the attachment state of the fine particles can be further stabilized.

Materials which easily cause filming, such as zinc stearate and magnesium stearate, in which these fine particles adhere to the image carrier in a film form during use, include: Naturally, filming easily occurs with respect to the toner, and the adhesive force with respect to the toner increases. Therefore, when the fine powder of the material that easily causes filming is adhered to the image carrier, the effect of stably increasing the transfer efficiency of the toner over a long period cannot be obtained. Although the state of adhesion of the fine particles on the image carrier, even if there is one type of fine particles,
A plurality of types of fine particles may be present at the same time. It suffices if fine particles are interposed between the toner and the image carrier so that the adhesive force between the toner and the image carrier can be reduced.

As a method of electrically attaching the fine particles, there is a method of dispersing the fine particles in a cloud shape and attaching the fine particles to the image carrier by the force of an electric field. As a method of dispersing and adhering the fine particles in a cloud shape, for example, a method using mechanical vibration, air, ultrasonic waves, an alternating electric field, or, for example, a roll shape, a brush shape, a web shape, a brush shape, A method of rotating, vibrating, and moving them while they are attached is exemplified. Furthermore, an adhesive layer may be provided on the image carrier, and the fine particles dispersed in a cloud shape by the above-described means may be adhered to the adhesive layer by sprinkling. As such an adhesive layer, a substance exhibiting stable adhesive properties over time is desirable. For example, silicone oil exhibiting low volatility and chemically stable properties is suitable. The fine particles once adhered remain on the photoreceptor in the non-image area, and a part of the image area, that is, a part where the toner image is formed, is peeled off at the same time as the transfer, but the same kind of fine particles remain in the developer. , The reduction of fine particles in the image area can be suppressed.

In the color image recording apparatus of the second embodiment, similarly to the first embodiment, at the time of a jam, the toner image formed at the time of the occurrence of the jam is finally transferred to the secondary intermediate transfer drum 36. By transferring the toner and collecting it by the fine particle applying means 10 provided on the secondary intermediate transfer drum 36, no stain was generated after the jam was cleared, and a good image could be formed. In this example, since all the driving units including the intermediate transfer body are drums or rolls, the color matching accuracy of each color can be increased, and the image quality is further improved.

[0057]

As described above, according to the present invention,
The toner formed on the image bearing member without supplying the recording medium after supplying the fine particles to the intermediate transfer body by the fine particle applying means and removing the recording medium being conveyed as necessary when a jam occurs. Since all the images are transferred to the intermediate transfer member and the unnecessary toner image is cleaned by the fine particle applying means, the processing for the occurrence of the jam can be quickly and reliably performed, and high-quality image recording can be realized. .

Further, in the image recording apparatus of the cleaner-less type responding to recent environmental requirements, a fine particle applying means for efficiently cleaning surplus toner when a jam occurs is provided, so that a long life, small size and high quality image can be obtained. A recording device can be provided. Further, the distance between the fine particle applying means and the most upstream transfer position on the intermediate transfer body provided with the fine particle applying means is determined by the following procedure. After the jam, the image carrier is restarted and the toner image is first transferred to the intermediate transfer body. Before the intermediate transfer member has moved,
The fine particles can be supplied to the surface of the intermediate transfer member cleaned by the jam without requiring any special time,
High productivity and transfer efficiency can always be maintained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an image recording apparatus according to a first embodiment of the present invention.

FIG. 2 is a timing chart showing a return sequence immediately after the occurrence of a jam according to the present invention.

FIG. 3 is a configuration diagram of an image recording apparatus according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating an example of a photosensitive drum.

FIG. 5 is a cross-sectional view illustrating an example of a charger.

FIG. 6 is a cross-sectional view illustrating an example of a developing device.

FIG. 7 is a cross-sectional view illustrating an example of a developing roll of a developing device.

FIG. 8 is a configuration diagram illustrating an example of a conventional color image recording apparatus.

FIG. 9 is a configuration diagram showing another example of a conventional color image recording apparatus.

[Explanation of symbols]

1Y, 1M, 1C, 1K ... photosensitive drum, 2Y, 2
M, 2C, 2K: charger, 4Y, 4M, 4C, 4K
... Developing device, 5 ... Intermediate transfer belt, 10 ...
Fine particle applying means, 35a, 35b ... primary intermediate transfer drum, 36 ... secondary intermediate transfer drum,

Claims (4)

[Claims] An image recording apparatus for primary-transferring toner images formed on a plurality of image carriers to an intermediate transfer member and secondary-transferring the toner images to a recording medium, comprising: A fine particle applying means for supplying fine particles having a small diameter is provided. When a jam occurs, the recording medium being conveyed is removed if necessary, and then the image carrier is supplied under the control of the control means without supplying the recording medium. An image characterized in that the toner image formed on the toner image is transferred to an intermediate transfer member provided with fine particles, and a potential having a polarity opposite to the charging polarity of the toner is applied, and the toner image is collected by the fine particle applying means. Recording device. 2. The method according to claim 1, wherein the toner images formed on the plurality of image bearing members are primarily transferred to a smaller number of primary intermediate transfer members than the image bearing members, and the toner images on the plurality of primary intermediate transfer members are transferred to the other two. In an image recording apparatus for performing secondary transfer to a secondary intermediate transfer member and tertiary transfer of the toner image to a recording medium, a fine particle applying means for supplying fine particles having an average particle diameter smaller than the toner to the secondary intermediate transfer member is provided. Occasionally, after removing the recording medium being conveyed as necessary, under control of the control means, the toner image formed on the image carrier or on the primary intermediate transfer body without supplying the recording medium is fine particles. An image recording apparatus, wherein the toner image is transferred to the applied secondary intermediate transfer member, and a potential having a polarity opposite to the charged polarity of the toner is applied to collect the toner image by the fine particle applying means. 3. The image recording apparatus according to claim 1, wherein substantially spherical toner is used as a developer, and fine particles having an average particle diameter smaller than that of the toner are provided on the surface of the image carrier. An image recording apparatus according to any one of the preceding claims. 4. The image recording apparatus according to claim 1, wherein the distance between the fine particle applying means and the most upstream transfer position on the intermediate transfer member with which the fine particle applying means contacts. The image recording apparatus is characterized in that the distance is shorter than the distance that the intermediate transfer member moves before the image carrier is restarted after the jam and the toner image is first transferred to the intermediate transfer member.