JPH10186845A - Developing device and image forming device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent toner melted by heat from being fixed to a doctor blade and to prevent an electrifying device from being soiled by splashed toner. SOLUTION: When a magnet roller 12b and a developing sleeve 12a are rotated at a high speed in the case that an electrostatic latent image on a photoreceptor drum 1 is developed, the temperature of the doctor blade 13 regulating a developer image on the sleeve 12 is raised and the toner is splashed. Then, plural heat radiation plates 14 are projectingly formed from the blade 13 and the tip parts thereof are arranged close to the surface of the drum 1 so as to divide a peripheral space into a developing device 4 side and the electrifying device 2 side. Thus, the temperature of the blade 3 is prevented from rising and the toner is prevented from being splashed toward the electrifying device 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an image forming apparatus such as an electrophotographic type or an electrostatic recording type, and an image forming apparatus using the same.

[0002]

2. Description of the Related Art In a developing device mounted on an image forming apparatus such as a copying machine or a laser beam printer, there is a developing device using a developer as a means for visualizing an electrostatic latent image formed on an image carrier. General.

[0003] The developer includes a one-component developer composed of a magnetic toner and a one-component non-magnetic developer composed of a non-magnetic toner, and a two-component developer composed of a non-magnetic toner and a magnetic carrier. There is a two-component developer consisting of
In the case of a one-component developer, the charging of the toner is performed by friction between the toner and a developing roller (developer carrier), and in the case of a two-component developer, contact and friction between the toner and a carrier are performed.

The developer contained in the developing container is carried on the surface of the developing roller, and is conveyed to a developing position near a photosensitive drum (image carrier) with the rotation thereof, where a developing bias is applied to the developing roller. As a result, the toner moves from the developing roller to the photosensitive drum, adheres to the electrostatic latent image on the photosensitive drum, and develops this as a toner image.

[0005] At this time, the developer carried and conveyed on the surface of the developing roller is conveyed to the developing position after its thickness is regulated by a doctor blade on the way. The doctor blade is formed by a member having moderate elasticity,
It is pressed against the surface of the developing roller with an appropriate force. When the developer layer on the developing roller slips through the doctor blade with the rotation of the developing roller, the developer layer is controlled to an optimum amount and a uniform thickness, and then the electrostatic latent image is developed at the developing position as described above. It is offered to.

[0006]

However, with the recent demand for smaller and faster image forming apparatuses,
The problem of temperature rise inside the apparatus main body, particularly in the above-described developing device, has the following problems.

As the speed of the image forming apparatus increases, the developing roller also rotates at a high speed. Then, after long use, the developing roller is heated, and the toner in contact therewith is melted and fixed. This sticking of the toner frequently occurs particularly near the doctor blade.

The glass transition point (Tg point) of a toner generally used in a high-speed machine is around 50 to 65 ° C. When the peripheral speed of the developing roller is 350 mm / sec, the temperature at the center of the doctor blade after continuous use for 3 hours may be around 55 ° C., which may exceed the glass transition point. The rise is remarkable, and the fixation of the toner is remarkable.

In order to prevent the above-mentioned temperature rise, it is effective to secure a space for heat radiation. However, this is contrary to the recent miniaturization of image forming apparatuses, and thus it is difficult to realize it.

Next, it is conceivable to improve the toner to increase the Tg point. However, it is difficult to raise the Tg point because a fixing function of melting and fixing the toner on the latent image portion must be provided. There's a problem.

In order to improve image characteristics, the surface of the developing roller may be coated with a resin containing conductive powder. In this case, the surface of the developing roller after coating is more than the surface before coating. In addition, heat conductivity is deteriorated, and heat is not lost to a rise in temperature near the doctor blade, so that the surface temperature tends to rise. In particular, in a system in which the developing roller is constituted by a developing sleeve and a magnet roller, and the developing is performed by rotating the developing roller, an eddy current is generated due to the rotation of the magnet roller.

Further, as another problem, as the developing roller rotates at a high speed, toner scattered from the surface thereof increases,
The toner may adhere to a charging wire of a charger disposed upstream of the developing roller and cause poor charging and image deterioration.

The above-mentioned problems of toner sticking and scattering toner have been obstacles to realizing a high-speed machine capable of forming a good image.

Accordingly, the present invention provides a developing device which can be reduced in size and speed without causing charging failure and image deterioration.
It is an object to provide an image forming apparatus.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a structure in which a developer is attached to an electrostatic latent image formed on a movable image carrier at a developing position. In the developing device, the developing device is formed in a box shape and accommodates the developer, and a developing container having an opening in a portion opposed to the developing position, and is disposed rotatably in the opening. A developing roller that carries the developer in the developing container on the surface and transports the developer to the developing position; a regulating member that regulates the layer thickness of the developer carried and transported on the surface of the developing roller; and A heat radiating plate protruding toward the surface of the image carrier, the heat radiating plate having a base end attached to the regulating member and a distal end disposed close to the surface of the image carrier. The space around the image carrier is transferred to the image carrier. Partitioned into a developing device side of the direction and the upstream side, characterized in that.

In this case, the developing roller includes a rotatable magnetic member disposed inside, and a cylindrical non-magnetic member surrounding the magnetic member and carrying the developer on the surface thereof. Configuration.

Further, the surface of the non-magnetic member may include a resin and a conductive powder.

In the above configuration, the peripheral speed of the non-magnetic member is
It is particularly effective for those having a thickness of 350 mm / sec or more.

Further, a polarity opposite to the polarity of the developer may be applied to the regulating member.

Next, an electrostatic latent image forming means and a developing device are provided so as to face the rotatable image carrier, and the toner image formed on the image carrier is transferred onto a transfer material. In the image forming apparatus, the plurality of developing devices are any of the developing devices described above.

Next, at least two sets including an electrostatic latent image forming means and a developing device are provided so as to face the rotatable image carrier, and the image carrier is rotated by one rotation of the image carrier. An image forming apparatus that forms at least two toner images on a surface of a carrier and collectively transfers these toner images onto a transfer material, wherein at least one of the plurality of developing devices is the developing device according to any one of the above. Device.

[Operation] Since the base end of the heat radiating plate is attached to the restricting member based on the above configuration, the restricting member whose temperature has been raised by, for example, high-speed rotation of the developing roller transfers its heat through the heat radiating plate. Is done.

Further, since the distal end of the heat radiating plate is arranged close to the surface of the image carrier, the space around the image carrier is separated by the heat radiating plate between the developing device side and the upstream side in the image carrier moving direction. Is divided into Therefore, the toner scattered to the upstream side from the developing roller of the developing device is blocked by the heat radiating plate, and its movement is prohibited.

That is, when the heat radiation plate is considered to be a part of the regulating member, the regulating member is a single member and has an effect of regulating the thickness of the developer layer on the developing roller. In addition, it also has the function of promoting heat radiation and the function of preventing scattered toner. For this reason, it also works effectively for downsizing the entire image forming apparatus.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. 1 shows a schematic configuration of an electrophotographic image forming apparatus as an example of an image forming apparatus according to the present invention.

The image forming apparatus shown in FIG. 1 includes a drum-shaped electrophotographic photosensitive member (hereinafter, referred to as “photosensitive drum”) 1 as an image carrier. The photosensitive drum 1 is rotatably supported by an apparatus main body (not shown) in the direction of arrow R1. The charging device (primary charging device) 2, the exposure device 3, the developing device 4, the transfer charging device 5, the separation charging device 6, the cleaner 7,
Further, a pre-exposure device 8 is provided. Further, a registration roller is provided on the upstream side of the transfer charging device 5 in the transport direction of the transfer material P (the direction of the arrow K1), and a fixing device 10 is provided on the downstream side.

The image forming apparatus having the above configuration operates as follows.

The photosensitive drum 1 is driven to rotate in the direction of arrow R1 by driving means (not shown), and its surface is uniformly charged by the charging device 2. The surface of the charged photosensitive drum 1 is subjected to optical scanning based on image information by the exposing means 3, and the charge of the light irradiating portion is removed to form an electrostatic latent image. The electrostatic latent image is developed as a toner image by attaching toner to the next developing device 4. The developing device 4
Will be described in detail later. The toner image on the photosensitive drum 1 is transferred to the transfer material P by the transfer charging device 5.
The transfer material P stored in the paper cassette is transported to the registration roller 9 by a paper feed roller and a transport roller (both not shown), and temporarily stopped there.
It is supplied in synchronization with the toner image on the photosensitive drum 1. The toner image on the photosensitive drum 1 is transferred to the transfer material P by the transfer charging device 5 as described above. The transfer material P after the transfer of the toner image is separated from the surface of the photosensitive drum 1 by the separation charger 6, and
0, where the toner image on the surface is heated and pressurized and fixed, and then discharged outside the apparatus main body. On the other hand, the photosensitive drum 1 after the transfer of the toner image has the transfer residual toner on the surface removed by the cleaner 7 and is discharged by the pre-exposure device 8 and then subjected to the next image formation starting from charging.

Next, the developing device 4 according to the present embodiment will be described in detail.

The developing device 4 is disposed on the right side of the photosensitive drum 1 in FIG.
, A regulating member 13, and a heat sink 14 as main constituent members.

The developing container 11 is formed in a box shape.
The developer is accommodated inside. An opening 11a is provided in a portion of the developing container 11 facing the developing position D. A stirring member 15 for stirring the developer by rotation and transporting the developer toward the opening is incorporated inside the developing container 11.

The developing roller 12 is provided in the opening 11a. The developing roller 11 has a rotatable magnet roller (magnetic member) 12a disposed inside, and a cylindrical developing sleeve (non-magnetic member) 12b surrounding the periphery thereof and carrying and carrying the developer on the surface. . The magnet roller 12a is formed in a cylindrical shape, and N poles and S poles are alternately arranged along the circumferential direction. As the magnet roller 12a, one having at least four poles, for example, one having eight poles, sixteen poles, or the like may be used.

In the developing sleeve 12b of this embodiment, stainless steel is used as a base material. However, stainless steel has disadvantages such as poor image characteristics such as a developing roller memory (sleeve ghost) and poor durability such as abrasion resistance. This situation is particularly remarkable in a one-component developer. In order to improve these properties, conductive powder and non-conductive powder,
A resin coating layer containing a solid lubricant and having fine irregularities on the surface is formed by spray coating or electrodeposition coating.

The coating layer is formed, for example, by dispersing a conductive acicular titanium oxide powder as a conductive powder (conductive powder) and a conductive carbon black powder in an epoxy cationic resin as a resin. Can be formed by electrodeposition coating.

As the conductive powder, other conductive ceramic powders such as a metal boride, a metal carbide, a metal nitride, and a metal oxide, a ceramic powder containing the conductive powder, and a ceramic powder. A powder whose surface is made more conductive by doping or plasma treatment with conductive ultrafine particles or the like may be used. In addition, as the non-conductive powder, titanium oxide, alumina, acrylic, PMM
A, urethane, polyethylene, nylon, melamine and the like can be used. Further, in order to further improve wear resistance, fluorine-based, melamine cyanurate, lauroyl-L-lysine, graphite, molybdenum disulfide and the like may be mixed as a solid lubricating powder. The shape of these powders is not particularly limited, and generally known spheres, squares, plates, needles, whiskers, irregular shapes and the like are used. The resin material is acrylic, PMM
A, urethane, melamine, etc. may be used, and in the case of an electrodeposition paint, both anionic and cationic are possible. The coating method may be a method by spraying or a method by immersion.

Next, as the restricting member 13, an elastic doctor blade formed long along the direction of the generatrix of the developing sleeve 12b is used. In the present embodiment, since the one-component magnetic toner is used, the doctor blade 13 is made of iron with chemical nickel plating, but other magnetic materials such as cobalt, nickel,
It may be a rare person. Also, depending on the type of toner such as a two-component toner, aluminum or ceramic, non-magnetic and excellent in thermal conductivity, SiC, BeO, AlN, Al ₂ O ₃ , S
An inorganic material such as iO ₂ , B ₂ O ₃ , and diamond may be used, an organic material may be used, or a combination thereof may be used. The doctor blade 13 has a leading edge disposed close to the surface of the developing sleeve 12b with a predetermined gap therebetween.
This regulates the thickness of the developer layer carried and conveyed on the surface of the developing sleeve 12b.

As shown in FIG. 1, the heat radiating plate 14, which is a feature of the present invention, projects from the doctor blade 13 serving as a regulating member toward the surface of the photosensitive drum 1, and its base end has a doctor end. The blade 13 is attached to the blade 13, and its tip is disposed close to the surface of the photosensitive drum 1.

FIG. 2 is a perspective view of the developing device 4 as viewed from the doctor blade 14 side. Here, the length of the doctor blade 14 in the direction along the developing roller 12 is L, the width from the base end to the tip is W, the pitch between the heat sinks is S,
Assuming that the thickness of the radiator plate 14 is t, in the present embodiment, three radiator plates 14 having different widths W are arranged, and L = 300 m
m, W = 30, 25, and 20 mm (in order from the top), S = 8 mm, and t = 1 mm. Thereby, the heat radiation area of the heat radiation plate 14 is increased.

Heat sink 14 for doctor blade 13
Can use an adhesive for the heat radiation type. Such adhesives include, for example, silicone elastomer for heat dissipation, SE4450, SC102 (manufactured by Dow Corning Toray Silicone Co., Ltd.). Such bonding with an adhesive is particularly effective when a magnetic material is used for the doctor blade 13 and a non-magnetic material is used for the radiator plate 14, that is, when the material of the doctor blade 13 and the material of the radiator plate 14 are different. .

On the other hand, the radiator plate 14 is
When the same material is used, the cost can be reduced by integrally molding the two.

As described above, the heat radiating plate 14 can effectively prevent the temperature of the doctor blade 13 from rising by increasing the heat radiating area. In addition, by disposing the tip portion close to the surface of the photosensitive drum 1, the photosensitive drum 1
The surrounding space can be divided into the developing device 4 side and the upstream side in the moving direction of the photosensitive drum 1 surface.
Accordingly, it is possible to prevent the toner from the developing device 4 from scattering to the upstream side and contaminating the charging device 5.

FIG. 3 shows the temperature of the central part of each of the conventional doctor blade and the doctor blade (doctor blade having the radiator plate 14) 13 of the first embodiment. Are indicated by black circles). The horizontal axis represents the peripheral speed of the developing sleeve 12.
Each doctor blade is coated with a resin to improve image characteristics. The temperature at the center of the doctor blade when the developing sleeve was continuously used for each peripheral speed for 3 hours was measured. The measuring instrument is a temperature measuring instrument manufactured by Anritsu Keiki Co., Ltd .: H
L-200 temperature probe: N-171E-00 was used.

As a result, when the peripheral speed of the conventional doctor blade reaches 350 mm / sec, the central temperature approaches 53 ° C. and approaches the glass transition point (Tg point: 55 ° C.) of the toner.
At 0 m, it exceeded the Tg point. On the other hand, the doctor blade 13 of the first embodiment having the heat radiating plate 14 has a peripheral speed of 150 to 550 mm / sec in a range of 2 to 1 compared with the conventional blade.
Even at 650 mm / sec, the temperature was lowered by 4 ° C. to 49 ° C., which was below the Tg point of the toner.

FIG. 4 is a table showing the relationship between the peripheral speed of the developing sleeve and the fixed state of the toner for the conventional doctor blade and the doctor blade 13 of the first embodiment. From this result, it can be seen that the provision of the heat radiating plate 14 enables
Even when the developing sleeve 12 rotates at a high speed exceeding sec., it is possible to prevent the toner from sticking.

Further, the provision of the heat radiating plate 14 reduced the amount of scattered toner. As a result, the contamination of the discharge wire 2a of the charging device 2 (see FIG. 1) was reduced. Specifically, the image defect due to the contamination of the discharge wire 2a has no problem even after the endurance of 800,000 sheets in a low humidity environment.
The durability life can be extended up to twice. The heat sink 1
3 is applied with an electric bias having a polarity opposite to that of the toner.
4 and the efficiency of collecting scattered toner between the heat radiating plates 14 is increased, and the durable life of the discharge wire 2a can be further extended.

By arranging the radiator plate 14 as described above, it is possible to prevent the toner from being fused by suppressing the heat of the doctor blade 13 and to reduce unnecessary scattering of the toner, thereby contaminating the charging device 2 with the scattered toner. Can be effectively prevented, and poor charging due to contamination can be effectively prevented. That is,
The above-mentioned heat radiating plate 14 can realize not only the heat radiating function but also the toner scattering preventing function.
Moreover, as is clear from FIG. 1, the heat radiating plate 14 can be compactly arranged between the doctor blade 13 and the surface of the photosensitive drum 1, so that it is not necessary to provide a space for installation. There is no possibility that the heat radiation plate 14 will cause an increase in the size of the image forming apparatus.

It is preferable that the heat radiating plates 14 have a large heat radiating area for each heat radiating plate 14 in order to increase the heat radiating area, and a plurality of the heat radiating plates 14 are arranged. Also,
When a plurality of heat radiating plates are provided, the lower heat radiating plate 14 is provided so as to effectively capture the scattered toner in the gap between the heat radiating plates 14.
It is preferable that the position of the tip is retracted toward the doctor blade 13 side. However, all of these conditions require that the space for the arrangement should not be unduly increased, and that the writing of an image by the exposure means 3 should not be hindered. <Second Embodiment> FIG. 5 is a longitudinal sectional view schematically showing the vicinity of a developing device according to a second embodiment. In this embodiment, a photosensitive belt 100 is used as the image carrier 1. The developing device 104 includes a developing sleeve 101 as a non-magnetic member made of stainless steel and a magnet roller 102 as a magnetic member having alternately different polarities inside the developing sleeve 101. The method is adopted. In this embodiment, the magnet roller 102 is rotated in the clockwise direction in the figure, and the developing sleeve 101 is rotated in the opposite counterclockwise direction. Such a developing method is suitable for a high-speed machine because the developer moves in the same direction as the developing sleeve 101 and the supply amount of the developer to the photosensitive belt 100 increases. However, since the magnet roller 102 is rotated, an eddy current is generated in the developing sleeve 101 and the regulating member (doctor blade) 105, and the temperature of both the developing sleeve 101 and the doctor blade 105 increases sharply due to the Joule heat.
In addition, by rotating the magnet roller 102, the direction of the magnetic pole constantly changes on the developing sleeve 101, which promotes disturbance to the developer. Therefore, although this method is suitable for a high-speed machine, toner scattering is severe.

Therefore, in the present embodiment, in the developing system of the magnet roller rotating type, the radiating plate 103 is provided on the doctor blade 105 which is a regulating member. Thereby, heat dissipation is promoted and scattering of toner is prevented.

FIG. 6 shows a temperature rise curve of the central portion of the doctor blade 103 in the developing device 104 having the structure shown in FIG. In the figure, the white circles are before the heat radiation plate 103 is provided, while the black circles are after the image heat radiation plate 103 is provided. The image forming apparatus has a process speed of 350 mm / sec and a peripheral speed of the developing sleeve of 450 mm / sec.
, And images were continuously formed. as a result,
The central temperature of the doctor blade is about 32
Although the glass point transfer (Tg point: 55 ° C.) of the toner was exceeded after one minute, in the case of this embodiment, the Tg point was not exceeded even after 70 minutes. <Third Embodiment> FIG. 7 shows a schematic configuration of a third embodiment. The image forming apparatus according to the present embodiment is a one-pass multi-color image forming apparatus, that is, a multi-color image (two in FIG. 7) is formed on the photosensitive drum 1 by one rotation of the photosensitive drum 1 in the direction of arrow R1.
(Color) forms a toner image, and is particularly characterized by a primary charger and a recharger. In order to perform reversal development in each development process in the one-pass multicolor image forming apparatus (or to perform regular development in each development process), the potential once lowered by exposure in the first latent image process is changed to the second latent image process. In order to form a latent image in the image process, the photosensitive drum 1
Need to be charged. Specifically, the photosensitive drum 1 composed of an OPC drum is charged to −700 V by a primary charger, then a first latent image is formed by the exposure device 21, and first development is performed by the first developing device 22. After that, the potential of the photosensitive drum 1 is lowered, so that the photosensitive drum 1 is again charged to -600 V before the second latent image process by the second exposure device 23 is started.
Must be charged to -700V.

As described above, in the multi-color image forming apparatus, since a plurality of developing devices must be arranged on the periphery of the photosensitive drum, each of the developing devices 22 and 24 is considerably restricted in space. .

For such developing devices 22 and 24,
By applying the present invention, that is, by providing a heat generating plate 14 having both a heat generating action and a toner scattering preventing action, heat generation can be prevented, toner scattering can be prevented, and further space saving can be realized. In addition, the developer in the second developing device 24 mixes with the developer in the first developing device 22 as scattered toner, and conversely, the toner in the first developing device 22 It could be prevented from being mixed into the agent.

In this embodiment, as shown in FIG. 7, the photosensitive drum 1 is used as an image carrier, a developing device of a color other than black is used as the first developing device 22, and a black developing device is used as the second developing device 24. The developing of the second developing device 24 used was jumping development. In addition, reversal development was used for each development method. <Embodiment 4> FIGS. 8A and 8B show Embodiment 4.
Is shown. In order to enhance the heat radiation effect of the doctor blade 13 itself, the surface area of the doctor blade 13 is increased. FIG. 8A shows a case where a large number of hemispherical projections 13 a are provided on both the front and back surfaces of the doctor blade 13, and FIG. A large number of recesses 13b are provided. In any case, the doctor blade 13 was able to perform more effective heat dissipation by increasing the surface area, and thus was able to effectively suppress the temperature rise.

In each of the following embodiments, the same heat radiation effect was obtained even when stainless steel was used for the doctor blade. <Fifth Embodiment> FIG. 9 shows a fifth embodiment. In the above-described first to fourth embodiments, heat sink 14
Are arranged with their longitudinal direction oriented horizontally, but in the present embodiment, a large number are arranged in the vertical direction. This is arranged vertically so that the convection of the heated air near the doctor blade 13 is performed smoothly.

The projecting dimension of the heat radiator 14 does not affect the formation of a magnetic field at the time of development, does not hinder the writing of a latent image on the photosensitive drum, and has as large an area as possible within an easy range of integral formation. It is preferable to do so. In the present embodiment, as shown in FIG.
m, width W = 10 mm, pitch S = 10 mm, plate thickness t = 1
mm.

Further, as the image carrier, a φ80 mm amorphous-silicon photosensitive drum was used, and the process speed at that time was as high as 500 mm / sec.

As a result, the heat radiating plate 14 having the above-described structure can suppress the temperature rise of the doctor blade 13 and significantly reduce the amount of toner scattering, thereby forming a stable developer layer on the developing sleeve. I was able to. The present embodiment has a particularly remarkable effect in a high-speed machine that rotates a magnet roller as a magnetic member in the developing roller.

[0057]

As described above, according to the present invention,
A heat radiating plate protrudes from the regulating member for regulating the thickness of the developer layer on the developing roller toward the surface of the image carrier, and a base end thereof is attached to the regulating member, and a distal end is disposed close to the surface of the image carrier. Thus, the heat radiating plate functions as a member for preventing the temperature of the regulating member from rising, and as a member for dividing the space around the image carrier into the developing device side and the upstream side thereof to prevent the toner from scattering. Thus, it is possible to prevent the toner from sticking to the regulating member, and to prevent the charging device from being contaminated by toner scattering and causing poor charging. In addition, since it is not necessary to provide a space for mounting the heat-dissipating plate, it is possible to prevent an increase in the size of the developing device.

Further, by coating a resin containing a conductive powder on a non-magnetic member (for example, a developing sleeve), image characteristics such as a sleeve ghost can be remarkably improved.

Further, in the case where two or more developing devices are provided around the image carrier, it is possible to prevent other toner from being mixed into the developer in each developing device due to developer scattering (toner scattering). can do.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of an image forming apparatus equipped with a developing device according to a first embodiment.

FIG. 2 is a perspective view illustrating a configuration of a developing device according to the first embodiment.

FIG. 3 is a diagram for comparing the relationship between the peripheral speed of the developing sleeve and the center temperature of the doctor blade in the first embodiment with that of the related art.

FIG. 4 is a diagram comparing a conventional doctor blade without a heat radiating plate and a doctor blade of the first embodiment having a heat radiating plate with respect to a relationship between a peripheral speed of a developing sleeve and toner fixation in the first embodiment.

FIG. 5 is a diagram illustrating a schematic configuration of a developing device according to a second embodiment.

FIG. 6 is a diagram for comparing the relationship between the elapsed time and the doctor blade center temperature with the conventional one in the second embodiment.

FIG. 7 is a diagram illustrating a state where the developing device according to the third embodiment is arranged around an image carrier.

FIG. 8A is a perspective view showing a surface shape of a doctor blade according to a fourth embodiment. (B) is a perspective view showing another surface shape of the doctor blade of Embodiment 4.

FIG. 9 is a perspective view illustrating a configuration of a developing device according to a fifth embodiment.

FIG. 10 is a diagram showing dimensions of a heat sink according to a fifth embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 image carrier (photosensitive drum) 2 developing device (primary charger) 3, 21, 23 exposure means 4, 22, 24 developing device 5 transfer charger 6 separation charger 7 cleaner 8 pre-exposure device 9 registration roller 10 charger DESCRIPTION OF SYMBOLS 11 Developing container 11a Opening 12 Developing roller 12a Magnetic member (magnet roller) 12b Non-magnetic member (developing sleeve) 13 Regulatory member (doctor blade) 14 Heat sink P Transfer material

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazushige Nishiyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (7)

[Claims] 1. A developing device for developing a developer by attaching a developer at a developing position to an electrostatic latent image formed on a surface of a movable image carrier, wherein the developing device is formed in a box shape and stores the developer. A developing container having an opening at a portion opposed to the developing position; a developing device rotatably disposed at the opening, carrying the developer in the developing container on the surface and transporting the developer to the developing position; A roller, a regulating member for regulating a layer thickness of the developer carried and conveyed on the surface of the developing roller, and a heat radiating plate protruding from the regulating member toward the surface of the image carrier. The plate has a base end attached to the regulating member,
A tip portion disposed close to the surface of the image carrier, and dividing a space around the image carrier into a developing device side and an upstream side in a moving direction of the image carrier. Developing device. 2. The developing roller includes a rotatable magnetic member disposed inside, and a cylindrical non-magnetic member that surrounds the magnetic member and carries and transports the developer on the surface. The developing device according to claim 1, wherein: 3. The developing device according to claim 2, wherein the surface of the non-magnetic member contains a resin and a conductive powder. 4. The peripheral speed of the non-magnetic member is 350 mm /
The developing device according to claim 2, wherein the length is at least sec. 5. The developing device according to claim 1, wherein a polarity opposite to a polarity of the developer is applied to the regulating member. 6. An image bearing member which faces a rotatable image carrier,
6. An image forming apparatus provided with an electrostatic latent image forming means and a developing device, and for transferring a toner image formed on the image carrier onto a transfer material, wherein the plurality of developing devices are provided. An image forming apparatus, which is the developing device according to any one of the preceding claims. 7. An image bearing member which faces a rotatable image carrier,
At least two sets each including the electrostatic latent image forming means and the developing device
An image forming apparatus that is assembled and arranged to form at least two toner images on the surface of the image carrier by one rotation of the image carrier, and to transfer these toner images collectively onto a transfer material; At least one of the developing devices according to claim 1;
An image forming apparatus, comprising: the developing device according to claim 5.