JPS6357793B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) This invention relates to a developing device used in an electronic copying machine.

(Prior Art) Generally, there are various types of developing devices for electronic copying machines. Among them, the one that has been put into practical use has a magnetic roller installed inside the main body. The magnetic toner stored in the toner supply unit, so-called one-component toner, or a mixture of carrier (magnetic component) and toner is adsorbed to form a magnetic brush, and this magnetic brush is brought into sliding contact with the photoreceptor. Most of them are designed to supply magnetic toner or toner to the toner.

(Problems to be Solved by the Invention) However, in this type of toner supply system using a magnetic roller as a basic structure, the magnetic roller is expensive and it is difficult to reduce the manufacturing cost. Furthermore, the adjustment between the magnetic roller and the photoreceptor is delicate, often requiring precision of 0.1 mm, which requires a complicated mechanism to meet that precision. Particularly in terms of accuracy, one-component toner has a strong tendency to do so.

In addition, in the case of a device that supplies toner using a carrier, the carrier itself has a limited lifespan and needs to be replaced periodically, for example, every 10,000 to 20,000 copies. This creates a problem in that it has to be replaced every time, which requires a lot of time and effort.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a developing roller that is installed opposite to an image bearing member and applies toner to the image bearing member, and a developing roller that applies toner to the image bearing member. a toner supply unit that supplies toner to the roller, and the developing roller includes an elastic core and a surface bristles that are detachably provided on the outer peripheral surface of the core and come into contact with the image carrier. The brush body is characterized by having a cylindrical brush body without a seam.

(Function) By the above means, it is possible to eliminate the labor involved in replacing the carrier, etc., and to simplify the structure without requiring much dimensional accuracy in adjusting the distance between the photoreceptor and the photoreceptor.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. Reference numeral 1 in FIGS. 1 and 2 is a main body of an electronic copying machine, and a document table 2 is installed on the top surface of the main body 1 so as to be able to move back and forth. Further, a photoreceptor 3 serving as an image carrier is rotatably disposed approximately in the center of the main body 1 . The photoreceptor 3 is constructed by providing a zinc oxide photoreceptor coating on the circumferential surface of an aluminum cylinder. A charger 4, a developing device 5, a transfer device 6, and a cleaning device 7 are arranged around the photoconductor 3 in numerical order, in contact with the photoconductor surface 3a, which is the circumferential surface of the photoconductor 3. This constitutes a contact type copying machine. In addition, on the lower side of the main body 1,
A paper transport path 8 passing through a transfer device 6 is provided along the longitudinal direction. In this paper conveyance path 8, a paper feed mechanism 9 consisting of paper feed rollers 9a..., the above-mentioned transfer device 6, a paper ejection mechanism 10 consisting of paper ejection rollers 10a..., and a fixing device 11 are arranged, respectively, from the base end side. ing. A paper feed cassette 12 is provided at the base end of the paper transport path 8 and is detachably attached to the main body 1. Further, a paper output tray 13a is detachably attached to the main body 1 at the extending end of the paper transport path 8.
is provided. Note that P is paper stored in the paper feed cassette 12.

Further, on the upper side of the main body 1, an exposure device 15 is provided which includes an illumination system 13 consisting of an illumination lamp and an optical fiber lens 14.

Reference numeral 16 denotes a drive motor, which operates each of the mechanical parts described above, rotates the photoreceptor 3 from the top to the bottom at a circumferential speed of, for example, 80 mm/s, and also rotates the document table 2 to the photoreceptor. It is made to reciprocate in synchronization with the rotation of the body 3.

Also, 17 is the main switch, 18 is the control panel 1
Copy button provided on 9, 20 a button to increase the copy density, 21 a button to decrease the copy density, 22 a copy number setting button, 23 a copy number display window, and 24 the status of the copying machine. This is a display window that displays. Further, reference numeral 25 denotes a mounting port for the developing device 5, through which the developing device 5 is mounted.
This developing device 5 will be explained later.

When making copies using the electronic copying machine configured in this way, the main switch 17
With is turned ON, first place a document (not shown) on the document table 2. Next, control panel 19
Copy operation according to the desired copy using the buttons above. Then, with this copy operation, the original platen 2
moves forward, the photoreceptor 3 rotates, and each mechanism operates.

That is, the original placed on the original platen 2 is illuminated by the illumination system 13, and an image of the original is formed on the photosensitive surface 3a via the optical fiber lens 14. On the other hand, the photosensitive surface 3a of the photoreceptor 3 is sequentially charged by a charger 4, and the optical fiber lens 14 is placed on the photosensitive surface 3a at the latter stage of this charging process.
The image from the photosensitive surface 3a is formed to form a latent image on the photosensitive surface 3a. Next, the latent image is developed into a toner image by a developing device 5, and further reaches a transfer device 6. On the other hand, in the paper feeding system, by the operation of the paper feeding mechanism 9, sheets of paper P are taken out one by one from the paper feeding cassette 12, and transferred to the transfer device 6 and the photosensitive surface 3a via the paper transport path 8.
The paper is transported to the transfer section, which is the contact surface with the paper. Then, the toner image is transferred onto the paper P at this transfer section. Further, the paper P after the transfer is guided to the fixing device 11 by the paper ejection mechanism 10, and is fixed in the fixing device 11. After this, the paper P is transferred to the paper output tray 13.
The paper is ejected to point a and the copy is completed. On the other hand, the photosensitive surface 3a that has completed the transfer process is thoroughly cleaned by the cleaning device 7, and then the charging process is started again.

Copies are made based on these series of copying processes.

Note that in the copying process described above, the copying process equipment is brought into contact with the photosensitive surface 3a;
Since a is formed of a zinc oxide-based photosensitive coating film with excellent strength, it does not damage the photosensitive surface 3a.

The structure of the developing device 5 of the electronic copying machine constructed in this manner is shown in FIG. Describing the structure of this developing device 5, 25a, 25a in the figure,
Reference numeral 25b designates a pair of side frames formed of plastic material that constitute the main body 26 of the developing device 5;
A casing 27 and a casing 2 made of aluminum are formed between the side frames 25a and 25b.
8 is constructed, a toner supply chamber 29 which is a toner supply section is installed on the upper side, and a roller chamber 3 is installed on the lower side.
0 constitutes a main body 26. In the toner supply chamber 29 of this main body 26, a toner T made of carbon and resin with a particle size distribution center of 10 μm is stored.
is stored. Also, the side frames 25a, 25
A lid 31 is provided on the upper side of b in a single-opening manner so that the toner supply port 29a of the toner supply chamber 29 can be opened and closed. In addition, 32a, 32
b is a plate-shaped magnet attached to the upper end of the side frames 25a, 25b, which attracts and fixes the lid 31 when the lid is closed, and also closes the toner supply port 29.
It forms the seal of a. Further, 33 and 34 are urethane foams attached to the upper ends of the casings 27 and 28, which similarly seal the toner supply port 29a when the lid body 31 is closed.

Further, in the roller chamber 30 of the main body 26, three rollers, a first brush roller 35, a second brush roller 36, and a developing fur brush roller 37, each rotating along the width direction. It is freely installed and constitutes a conveyance system for the toner T stored in the toner supply chamber 29. Note that details regarding the arrangement, materials, power supply, etc. of the first brush roller 35, the second brush roller 36, and the developing fur brush roller 37 will be explained later.

Handles 38, 38 for transportation are provided on both sides of the main body of the developing device 5 configured as described above. These handles 38, 38 are attached to support shafts 3, which have lever bodies 38a, 38a formed in a substantially L-shape, and the middle portions of which are provided on the side frames 25a, 25b.
9 and 39, and is constructed in a pivoting form that allows rotation. Springs 40, 40 are attached to one ends of the lever bodies 38a, 38a, and constantly urge the lever bodies 38a, 38a downward. Note that 41, 41 are engagement protrusions for positioning, and 42, 42 are biasing members that restrict the amount of upward rotation of the lever bodies 38a, 38a. However,
By lifting the upper portions of the lever bodies 38a, 38a upward, the developing device 5 can be transported.
It can be attached to the main body 1 via 5.

The structure of the main body 1 that receives the developing device 5 is as shown in FIG. That is, in the figure, 42a and 42b are a pair of side plates constituting the main body 1, and between these side plates 42a and 42b, a guide plate 43 arranged diagonally is installed, and communicates with the mounting port 25 on the side. Further, it constitutes a device housing section 44 facing the photosensitive surface 3a of the photoconductor 3. On the widthwise side of this guide plate 43, a pair of guides 45, 45 made of cut and raised pieces corresponding to the width dimension of the main body 26 and corresponding to the engaging protrusions 41, 41 of the handles 38, 38 are provided. A pair of engagement holes 46, 46 are bored therein. In addition,
Reference numeral 47 denotes a positioning stay installed at a lower portion of the device housing portion 44. However, the device port 25
The developing device 5 is stored in the device storage section 44 through the
The sides are positioned by guide plates 43, the widthwise sides are positioned by guides 45, 45, and the lower part is positioned by stays 47. Further, the developing device 5 includes a handle 3
The engagement protrusions 41, 41 of 8, 38 are connected to the engagement holes 46, 4.
6, it becomes a complete lock state, and the 5th
As shown in FIGS. 6A and 6B, attachment is performed at a predetermined location in contact with the photoreceptor 3. As shown in FIG. When removing the developing device 5 from the main body 1, the locking mode is released by lifting the lever bodies 38a, 38a upward, and then by lifting the lever bodies 38a upward, the developing device 5 is removed. can be removed.

Next, the first brush roller 35, the second brush roller 36, and the fur brush roller 37 for development.
I will explain about it. First, each of these rollers 35,
36 and 37, the first
The brush roller 35 is arranged on the bottom side of the roller chamber 30. A part of the circumferential surface of the first brush roller 35 faces into the toner supply chamber 29 through the outlet 29b of the toner supply chamber 29. A second brush roller 35 is placed on the upper stage of this first brush roller 35.
The brush roller 36 is the first brush roller 3
Further, a developing brush roller 37 is similarly placed in contact with this second brush roller 36 . That is, each roller 35, 3 arranged in this way
6 and 37 are set so that the circumferential surface of the developing feed brush roller 37 and the photosensitive surface 3a of the photosensitive member 3 are in contact with each other when the developing device 5 is installed.

By the way, there are the following problems that arise when using such a contact developing fur brush roller 37.

That is, the surface of the photosensitive surface 3a is generally easily scratched, and it is not desirable to rub it strongly with the developing fur brush roller 37. Moreover, in order to carry out the development process, it is necessary to have a contact area of a certain amount or more with the photosensitive surface 3a and to take a certain development time.

For this purpose, two methods can be considered as a fur brush roller method for development.

One method is to make the hair long so that the long hair extends over the surface of the photosensitive surface 3a. Second, the developing fur brush roller 37 has a soft core, so that when it comes into contact with the photosensitive surface 3a,
It is made to flex.

However, if long bristles are used to stretch the surface of the photosensitive surface 3a, the bristles tend to curl and lose their elasticity. Moreover, the resistance when coming into contact with the second brush roller 36 is large, resulting in a problem that a large driving force is required.

In addition, if the core is made of a soft material, it is technically difficult to directly implant hair onto the core.

Due to these matters, the developing fur brush roller 37 has a charging characteristic (+ or -) as a material due to the relationship between the toner T and the photosensitive surface 3a and the relationship of imparting an electric charge to the toner T.
Moreover, it is conductive and can stably obtain a predetermined electrical resistance. Furthermore, the bristles are uniform, there is no shedding, and the bristles are excellent in abrasion resistance. In addition, the toner T has a bias for imparting a charge to the toner T. A necessary condition is that a potential is applied.

According to an embodiment of the invention, the developing fur brush roller 37 is constructed as shown in FIG.

That is, in the figure, 48 is a rotating shaft made of aluminum as a mandrel, and the outer peripheral surface of this rotating shaft 48 is provided with foamed polyurethane, such as EMM polyurethane (trade name: MTP Kasei) 50, and is used as a developing surface. It constitutes a highly flexible cylindrical core body 49 of the brush roller 37. In addition, EMM polyurethane 50 has a hardness of 23 ± 5 kg (JIS standard K-
6401 test method), impact resilience of 45% or less is used.

(Suitable according to experimental data) A conductive adhesive layer 53 is continuously provided on the outer circumferential surface and end surface of the core body 49 configured as described above, and a form of conduction between the rotating shaft 48 and the outer circumferential surface of the core body 49 is established. It consists of Furthermore, this conductive adhesive layer 5
A cylindrical brush body 51 is removably attached in the direction of the arrow on the outer peripheral side of the roller 3, and a soft type developing fur brush roller 37 with a roller diameter of φ30 is attached.
It consists of

That is, the cylindrical brush body 51 is formed by weaving a cloth made of, for example, rayon material into a cylindrical shape, and is provided with a uniform, non-shedding surface bristles 52 on the outer periphery thereof. is,
It is configured so that it can be attached to and detached from the core body 49 depending on use. Further, the surface bristles 52 have been subjected to conductive treatment to have a conductive function, and are made of special rayon with excellent wear resistance.
It consists of...

Therefore, the surface hairs 52 can form a predetermined and stable electrical resistance.

Therefore, the developing fur brush roller 37
A cylindrical brush body 5 with brushed surface bristles 52 has all the characteristics as described above.
1 coated on the outer peripheral surface of the core body 49 is concluded to be optimal.

The surface fibers 52 are made of special rayon fibers with a length of 1.5 mm, a thickness of 1.5 d (denier), and an electrical resistance of 10 ⁸ ~
10 ⁹ Ω・cm.

Further, the second brush roller 36 is configured as shown in FIG.

That is, in the figure, 57 is a cylindrical core made of aluminum and molded together with the rotating shaft 58.
A cylindrically raised cloth 61 is provided on the outer peripheral surface of. A conductive adhesive layer 59 of the same quality as that used in the developing fur brush roller 37 is provided on the inside of this cloth 61, and furthermore, on the outside of this conductive adhesive layer 59, ethylene tetrafluoride is provided. A hard type brush roller 36 with a roller diameter of φ20 is provided with a surface hair body 60 made of seamless Teflon fiber with a fiber length of 3 mm.

More specifically, the surface hair body 60 is formed by raising the outer peripheral surface of a cylindrical cloth 61, and is constructed by covering the outer peripheral surface of the core body 57 with this cylindrical cloth 61 in duplicate.

Further, the first brush roller 35 is configured as shown in FIG. 9.

That is, in the figure, 62 is a cylindrical core made of aluminum and molded together with the rotating shaft 63.
A conductive adhesive layer 100 is provided on the outer peripheral surface of the conductive adhesive layer 100, and surface bristles 64 made of special rayon of the same quality as the developing fur brush roller 37 are provided on the outside of the conductive adhesive layer 100. The hair is flocked by electro-flocking, and constitutes a hard type brush roller 35 with a roller diameter of φ20.

Each roller 3 configured in this way
5, 36, 37 are the roller chambers 30 as described above.
An excess toner collection chamber 82 is disposed in a side cavity along the rotational direction of each roller 35, 36, 37.
a, 82b, and 82c are formed. The rotational shafts 48, 58, 63 of these rollers 35, 36, 37 are connected to the side frames 25a, 25a, 25a, 25b, 25a, 25b, 25a, 24b, 25a, 24b, 24a, 24a, 25a, 25a, 24a3, 24a3, 234a3, 232a3, 234a3, 233a4, 232a, 2500a, 2500b, 2500a, 2500b, 2400a, 2400a, 4000a, 2000a, 2000b, 250a, 300a, 400a, 400b, etc., respectively, through oil seals 71... and bearings 74...
5b, and is connected to a drive system 65 and a bias potential power supply system 66, which is bias means.

The settings of the rollers 35, 36, and 37 are as shown in FIGS. 10 and 11, and FIG. The figure shows the area around the first brush roller 35 and the second brush roller 36. That is, the developing fur brush roller 37 has the outside of the surface bristles 52 inserted into the photosensitive surface 3a by 1 mm to increase the contact area.

Further, the distance between the first brush roller 35 and the second brush roller 36 is 1 mm.

Next, the drive system 65 will be explained. This drive system 65 includes gears 67, 6 provided at one end of each roller 35, 36, 37 as shown in FIGS. 3 and 6.
8 and 69, the gear 67 meshes with the gear 68, and the gear 68 meshes with the gear 69. When the developing device 5 is installed, the gear 69
can engage with the driving gear 70 provided on the main body 1, and the driving force is applied to the gear 70 and the gear 6.
9, gear 68, and gear 67 in order to drive each roller 35, 36, and 37. In addition, the gear ratio of each gear 67, 68, 69 is
Gear 67: Gear 68: Gear 69 = 12:7:17, and the peripheral speed ratio of each roller 35, 36, 37 is V ₁ = 0.2 to 1.0V ₃ , V ₂ = 1.1 to 2.0V ₃
(However, V ₁ is the peripheral speed of the first brush roller 35,
(V ₂ is the circumferential speed of the second brush roller 36, V ₃ is the circumferential speed of the developing fur brush roller 37), approximately the first brush roller 35: second brush roller 36: developing Fur brush roller 37 = 19:32:20.

Thus, in the drive system 65, the first brush roller 35 rotates from the top to the bottom by the drive gear 70, and the second brush roller 36 rotates from the top to the bottom.
can rotate from the bottom to the top, and the developing fur brush roller 37 can rotate from the bottom to the top. That is,
The rollers 35, 36, and 37 that are in sliding contact can sequentially rotate along different rotational directions on their contact surfaces. The surface bristles 52, 59, and 64 are raised, and an appropriate amount of toner can be effectively supplied from the toner supply chamber 29 to the photosensitive surface 3a.

In addition, 72 is a urethane worm for sealing to prevent the toner T from entering the bearing portion of each roller 35, 36, 37, and 83 is a urethane worm that is in sliding contact with the circumferential surface of the first brush roller 35. This scraping body is a scraping means for regulating the amount of toner T conveyed by the roller 35 to a predetermined amount.

Next, the bias potential power supply system 66 will be explained. This bias potential feed system 66 is shown in FIG. It consists of a power receiving section 72a provided on the side of the main body 26 of the developing device 5 and a power feeding section 73 provided on the main body 1 of the copying machine shown in FIG. The power receiving section 72a and the power feeding section 73 will be explained as follows.

That is, if the power receiving unit 72a is explained,
In the figure, 75, 76, 77 are blades having spring properties as contacts, and these blades 75, 7
6, 77 are screwed to the outer surface of the side frame 25b, and each roller 35, 36,
The power receiving portion 72a is configured by a structure in which the end face of the rotating shaft of 37 is pressed against the end face of the rotating shaft. That is, the free end of the blade 75 contacts the end surface of the rotating shaft of the first brush roller 35, and the free end of the blade 76 contacts the end surface of the rotating shaft of the second brush roller 36. The blade 77 is in contact with the end surface of the rotary shaft of the fur brush roller 37.

The power feeding section 73 that receives the power receiving section 72a configured as described above is configured as follows. That is, 78 in the figure indicates the side frame 2.
Harnesses 79a and 79b connected to an intermediate voltage transformer (not shown) are fixed to this block 78 with set screws and nuts. Further, two blades 80a, 80b are provided on the block 78, and these blades 80a, 80b connect to the harnesses 79a, 79.
It is connected to the connection end of 9b and constitutes a power feeding section 73.

Then, when the developing device 5 is installed, the power receiving section 7
The second blade 75 and blade 80a are in contact with each other, and the second blade 77 and blade 80b are in contact with each other. That is, the power supply and each of the first brush rollers 35 and the developing fur brush 37 are electrically connected to each other, so that power can be supplied to each of the rollers 35 and 37. Specifically, a bias potential of DC-100V is applied to the first brush roller 35, and a bias potential of DC-100V is applied to the developing fur brush roller 37.
A bias potential of DC +250V is applied.

Moreover, when the blade 76 is attached, it comes into contact with the side plate 42b and the inner surface thereof to be grounded. That is, the side frame 25a is provided with a blade 81 that comes into contact with the stay 47 when installed, so that it can be grounded via the casings 27, 28 and the stay 47.

In the figure, 85 is a sealing urethane foam that prevents the toner T from scattering near the contact between the developing fur brush roller 37 and the photoreceptor 3, and 86 is a sealing foam that is used to ensure stable development. There is a gap.

Next, the operation of the developing device 5 constructed as described above will be explained based on the principle diagrams related to the developing process shown in FIGS. 5 and 12. However, 87 and 88 are power supplies that supply bias potential, and 89 is a ground.

Along with the copying operation described above, the first brush roller 35 and the developing fur brush roller 37
A bias voltage is applied to the surface bristles 64 of the first brush roller 35, and a bias potential of DC+250 V is applied to the surface bristles 52 of the developing fur brush roller 37. . Next, the toner supply chamber 29
The toner T inside is sequentially conveyed by the first brush roller 35. That is, the toner T adheres to the surface bristles 64 of the first brush roller 35 and is conveyed, and is further restricted to an appropriate amount by the scraper 83.
At this time, the toner T is positively charged by the frictional electric current caused by the sliding contact between the scraping body 83 and the surface bristles 64, and is further charged by the first
The toner T 2 receives a potential from the brush roller 35 and becomes positively charged toner T ₂ . Subsequently, the toner T ₂ is transported from the first brush roller 35 to the second brush roller 36. In other words, the toner T ₂ is transported by the surface hair body 6.
This is achieved by the combination of the electrostatic attraction force of the surface hairs 64, the density of the surface hairs 64, and the force mechanically held between the surface hairs 64.

However, at this stage, not all particles of the toner T ₂ are sufficiently charged, and when the toner T 2 is transferred to the second brush roller 36, the toner T that is still almost neutral is considerably charged. Mixed.

This is because not all toner particles may sufficiently contact the surface bristles 64 of the first brush roller 35, and in particular, toner particles outside the toner layer adhering to the surface bristles 64 are not charged. This is because it is difficult.

However, in transferring the toner T and toner T ₂ , the second brush roller 36 has surface bristles 60 made of tetrafluoroethylene material, so it is different from the first brush roller 35 . It has the characteristic of being negatively charged due to the rotational friction of the material.
Therefore, when toner T and toner T ₂ are transferred, toner T and toner T ₂ correspond to this negative charge.
is charged with the opposite polarity, positive. That is, at this stage, the first brush roller 35, the second
Since the surface bristles 64 and the surface bristles 60 of the brush roller 36 are rotating while biting into each other,
Triboelectric charging imparts a positive charge to all toner particles, eliminating electrostatically unstable toner particles. That is, the toner T and toner _T2 are positively charged by the second brush roller 36,
It becomes toner T ₃ with sufficient plus.

Then, the toner T ₃ is transferred to the second brush roller 36 by mechanical and electrostatic suction, and is conveyed to the fur brush roller 37 for development.

On the other hand, the surface bristles 52 of the developing fur brush roller 37 are biased to a negative potential by applying a negative bias potential.
The brush roller 36 electrostatically attracts and mechanically receives the sufficiently positively charged toner _T3 .
Then, this toner _T3 is supplied to the photosensitive surface 3a.
That is, as is well known, a part of the photosensitive surface 3a has a negative potential due to a latent image, and the toner T ₃ is applied electrostatically and mechanically to this negative potential portion, and a certain amount of image is generated. Development can be completed while meeting the development time.

Note that the second brush roller 36 is rotated in a direction different from that of the developing fur brush 37, and is set at a peripheral speed higher than that of the developing fur brush roller 37, so that the developing fur brush is always rotated. It functions to raise the surface bristles 52 of the roller 37, so that the surface bristles 52 do not come undone during operation.

In addition, if the amount of toner T ₃ accepted and supplied on the photosensitive surface 3a exceeds the limit, first the surface bristles 52 of the developing fur brush roller 37
If the storage capacity of the developing fur brush roller 37 is exceeded, in other words, if the excess toner is stored in the developing fur brush roller 37.
When the toner T ₃ of No. 7 becomes excessive, the second brush roller 36 collects the excess toner. That is, this is because the relative relationship between the suction force due to the negative potential of the developing fur brush roller 37 and the suction force applied to retain the toner of the second brush roller 36 is disrupted due to excess toner, and the suction force of the developing fur brush roller 37 is disrupted. This is done because the suction force of the second brush roller 36 exceeds the force, and the excess toner on the developing fur brush roller 37 is electrostatically transferred to the second brush roller 3.
6, and collection is performed. Note that the toner T ₃ that is not excessive is transferred to the fur brush roller 37 for development.
Needless to say, it is held by the suction ability of the surface hairs 52.

Then, the second brush roller 36 stores excess toner.

Incidentally, the surface bristles 52 of the second brush roller 36 are made of tetrafluoroethylene material, and one of the characteristics of the surface bristles 52 is that they have a very large toner-carrying capacity.

Therefore, the second brush roller 36 has an extremely large toner storage capacity and can sufficiently collect excess toner. According to experiments, the storage capacity is such that the surface hairs 52 are no longer visible and it looks like a cylinder of toner.

Therefore, the manner in which excess toner is collected in such a mechanism depends on the amount of triboelectricity of the toner T, the bias of each roller 35, 36, 37, and the surface hairs 52, 60, 64 of each roller 35, 36, 37. Material, this surface hair body 52,6
It is determined by the relationship of conductive resistance of 0.64, etc., and the combination described in the experimental example showed the best results.

Further, excess toner that cannot be completely collected by the second brush roller 36 is sequentially stored in the excess toner collection chamber 82c, and when a certain amount of storage is reached, it comes into contact with the first brush roller 35 and returns to the first brush roller 35. It is replenished by the brush roller 36.

Note that the excess toner collection chamber 82a includes the second brush roller 36 and the developing fur brush roller 3.
This is to collect excess toner discharged from both the excess toner recovery chamber 82a and the excess toner recovery chamber 82a. It is widened to prevent clogging due to excess toner.

Further, the excess toner collection chamber 80b is for collecting excess toner released from the first brush roller 35. Note that this excess toner collection chamber 80b has a gap 95, but since this gap 95 is extremely small, the toner T will not flow backwards into the excess toner recovery chamber 80b. .

Therefore, there is no need to replace the carrier at all, which is extremely convenient in terms of maintenance.

According to the embodiment described above, it is possible to provide a developing device with a simple structure suitable for toner T, so-called one-component toner, using an inexpensive developing fur brush roller 37 without using an expensive magnetic roller or real toner. can be supplied.

Moreover, the developing fur brush roller 37 is
Since the core body 49 is made of elastic EMM polyurethane 50 and is constructed as a soft type, it does not cause scratches on the surface of the photoconductor 3, and does not require much dimensional accuracy between the photoconductor 3 and the photoconductor 3. Never.

That is, according to experiments, for example, the hardness of EMM polyurethane 50 is 15 to 35 kg (JIS standard K-
6401 test method), the contact development area with the photoreceptor 3 due to deflection can be effectively widened, and the development time can be extended. Ta.

Moreover, if the EMM polyurethane 50 has a hardness in the range of 15 to 35 kg, in addition to the above-mentioned results, the dimensional accuracy between the photosensitive surface 3a and the photosensitive surface 3a will be poor, and in the unlikely event that the developing fur brush roller 37 Experimental data has been obtained that shows that even if the photoreceptor 3 is brought close to the photoreceptor 3, the photoreceptor 3 is not damaged.

Further, in the above embodiment, the first brush roller is located at the bottom, and the second brush roller and the developing roller are arranged above, but it may be arranged as shown in FIG. 13, for example.

That is, the toner supply chamber 90 is installed in the upper part,
A first brush roller 91 is provided at the lower stage of the toner supply chamber 90, and a fur brush roller 92 for development is provided at the lower stage of this first brush roller 91.
, and a second brush roller 93 is provided in contact with each of these rollers 91 and 92, thereby configuring the arrangement of the developing device 5.

As explained above, according to the present invention, a developing roller is constructed by duplicating a seamless cylindrical brush body having brushed surface bristles on the outer peripheral surface of a core made of an elastic material. The system receives the toner from the toner supply section and supplies the toner while being in contact with the surface of the image carrier, which eliminates the need for an expensive magnetic roller or
It is possible to perform toner development using a developing roller that does not require a carrier, and it is possible to provide a developing device suitable for one-component toner.

Therefore, there is no need to carry out work to replace the carrier, and the distance between the image carrier and the developing roller is reduced.
Dimensional accuracy for space adjustment is not required too much.

Furthermore, since the developing roller is composed of an elastic core, it is possible to effectively widen the developing area in contact with the image carrier, prolong the development time, and improve the surface area of the image carrier. It will not cause any damage.

Furthermore, since the developing roller is constructed by covering the core body with a cylindrical brush body, it is possible to easily create a developing roller that satisfies the required functions even if the core body is made of a material that is not suitable for electrostatic flocking. It is possible, and the effect is great.

Moreover, since the cylindrical brush body is seamless, the amount of toner supplied to the image carrier is always stable, and good copies can always be provided.

Further, if the core body and the cylindrical brush body are made detachable, the surface bristles can be replaced as necessary, and the degree of use can be improved.

[Brief explanation of drawings]

1 to 12 show an embodiment of the present invention, in which FIG. 1 is an external view of an electronic copying machine, FIG. 2 is a schematic configuration diagram thereof, and FIG. 3 is an overall exploded perspective view showing a developing device. FIG. 4 is a partially exploded perspective view showing the part of the main body that receives the developing device, FIG. 5 is a side sectional view showing the developing device when installed, FIG. 6 is a side view showing the drive system of the developing device, and FIG. The figure is a partial sectional view showing the developing roller, FIG. 8 is a partial sectional view showing the second brush roller, FIG. 9 is a partial sectional view showing the first brush roller, and FIG. 10 is a partial sectional view showing the developing roller and the photoreceptor. 11 is a side view showing the setting state of the first brush roller and the second brush roller; FIG. 12 is an explanatory principle diagram showing the state of toner supply to the photoreceptor; FIG. 13 is a partial sectional view showing another embodiment of the invention. 3... Image carrier (photoreceptor), 26... Main body, 2
9... Toner supply chamber (toner supply chamber), 37...
Fur brush roller for development (developing roller),
49... core body, 51... cylindrical brush body, 52...
surface hair.

Claims (1)

[Claims] 1. A developing roller installed to face an image bearing member and applying toner to the image bearing member, and a toner supply section supplying toner to the developing roller, the developing roller having an elastic core; A developing device comprising: a cylindrical brush body without a joint, which is detachably provided on the outer peripheral surface of the core body and has surface bristles that come into contact with the image carrier.