JPH03136079A - Developing device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of void and to obtain a picture having satisfactory density by making the driving direction of a magnetic-brush carrier equal to that of an electrostatic latent image carrier, and also setting the driving speed of the magnetic brush carrier in a magnetic-brush contact area so that it is the same as that of the photosensitive body. CONSTITUTION:The driving direction of each of the magnetic-brush carriers 12 and 13 in the magnetic-brush contact areas E and F, respectively, where a magnetic brush B is in contact with the electrostatic latent image carrier 18, is made equal to that of the electrostatic latent image carrier 18. Additionally the driving speed of each of the magnetic-brush carriers 12 and 13 in the magnetic-brush contact areas E and F, respectively, is set so that it is the same as that of the photosensitive body 18. In the magnetic-brush contact area, the magnetic brush B carried on the magnetic-brush carrier moves at the same speed as that of the photosensitive body while it is in contact with the photosensitive body, therefore the magnetic brush does not rub itself against the surface of the photosensitive body. Thus, the occurrence of so-called solid cross void can be prevented, and a picture having satisfactory density can be obtained.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a developing device installed in a copying machine or the like.

(Prior Art) A developing device whose main part is shown in FIG. 7 is installed in a copying machine.

In the figure, reference numeral 1 indicates a drum-shaped photoreceptor.

This photoreceptor 1 is designed to rotate clockwise.

An electrostatic latent image is formed on the photoreceptor 1 by a device not shown.

Reference numeral 2 indicates a developing sleeve made of a non-magnetic material, and a magnet 3 (not shown) is inside this developing sleeve 2.
is fixed to a stationary member. A magnetic brush B consisting of a carrier 4 and toner 5 is carried on the developing sleeve 2 by the magnetic field of the magnet 3. The developing sleeve 2 is designed to rotate counterclockwise. The rotational speed of the developing sleeve 2 is set so that the developing sleeve 2 is driven faster than the photoreceptor 1 in the magnetic brush contact area A.

An electrostatic latent image consisting of an image area and a non-image area is formed on the photoreceptor 1. At this time, the surface potential of the non-image area generally does not become Ov. Prevents toner from adhering to non-image areas,
In order to prevent the occurrence of background stains, the developing sleeve 2 is equipped with T.
JifFlt bias is missing. For example, if the image part potential is about 800V and the non-bothered part potential is 100V,
A developing bias of 20° is applied to the developing sleeve.

Next, the operation of this developing device will be explained.

The developing sleeve 2 rotates counterclockwise at a peripheral speed higher than that of the photoreceptor 1, and the toner 5 frictionally charged to a negative polarity is held on the carrier 4 on the sleeve 2, thereby forming a magnetic brush B.

Then, in the magnetic brush contact area A, the magnetic brush B carried by the developing sleeve 2 comes into contact with the electrostatic latent image of positive polarity on the photoreceptor 1 rotating clockwise, and the toner is transferred to the electrostatic latent image. 5 is supplied, and a toner image is formed on the photoreceptor 1.

Further, the toner image on the photoreceptor 1 is transferred to a transfer paper by a transfer device, and the toner image on the transfer paper is fixed by a fixing device and then discharged outside the machine.

(Problems to be Solved by the Invention) In the above-mentioned developing operation, the developing sleeve 2 is driven at a higher speed than the photoreceptor 1 in the magnetic brush contact area A. Therefore, in the magnetic brush contact area A, the magnetic brush B on the developing sleeve 2 moves while contacting the photoreceptor 1. That is, the magnetic brush B rubs the circumferential surface of the photoreceptor 1.

Furthermore, since the non-image area on the photoconductor 1 has a low potential with respect to Tfl and the image sleeve 2, the magnetic brush B is applied to the background surface of the photoconductor 1 on which the electrostatic latent image is not formed, as shown in FIG. When the toner 5 comes into contact with the carrier 4, the toner 5 on the carrier 4 escapes to the root side of the carrier 4, as shown in FIG.

When the toner 5 escapes from the carrier 4 in this manner, the carrier 4 becomes charged with a positive polarity, that is, has a so-called counter charge. If the carrier 4 comes into contact with the toner image on the photoreceptor 1 in such a state, the carrier 4 will attract the toner forming the toner image, and there is a risk that white spots will occur in the copied image.

In particular, at the boundary C between the toner image and the background where the images intersect as shown in FIGS. 10 and 11, due to the edge effect of the electric field, the carrier with the countercharger attracts the toner image to a certain extent. becomes strong, and white spots in the image transferred to the transfer paper S are likely to occur in such areas. This white spot in the copied image is commonly referred to as a solid cross white spot.

In the above conventional example, since the driving direction of the developing sleeve 2 and the photoconductor 1 in the magnetic brush contact area A is the same, white spots occur at the rear end of the image. If the driving directions of photoreceptor 2 and photoreceptor 1 are different, similar white spots will occur at the leading edge of the image.

The driving directions of the developing sleeve 2 and the photoreceptor 1 in the magnetic brush contact area A are different, and white spots occur at the leading edge of the image because the magnetic brush comes into contact with the background part due to the above phenomenon, and the toner on the carrier is removed. This is because, after the toner has escaped to the root side of the carrier, this magnetic brush comes into contact with the electrostatic latent image on the photoreceptor, so that the toner is not supplied to the electrostatic latent image.

In order to prevent white spots on the copied image, either the width of the magnetic brush contact area A is reduced to reduce the contact of the magnetic brush B with the background of the photoreceptor 1, or the width of the developing sleeve 2 in the magnetic brush contact area A is reduced. It is conceivable to make the driving speed of the photoreceptor 1 equal to the driving speed of the photoreceptor 1 so that the magnetic brush B does not rub on the photoreceptor 1.

However, when these means are used, the magnetic brush B
Therefore, the amount of I/toner supplied to the electrostatic latent image on the photoreceptor 1 becomes insufficient, resulting in a problem that the image density decreases.

(Means for Solving the Problems) The present invention has been made in order to solve the above-mentioned conventional problems, and the invention of claim 1 is directed to the electrostatic latent image carrier being driven. Develop by supplying toner to the latent image.

In order to form a toner image on the electrostatic latent image carrier, a plurality of magnetic brush carriers are made of toner and carrier, carry a magnetic brush that comes into contact with the electrostatic latent image carrier, and are freely drivable.
In the equipped developing device.

The driving direction of the magnetic brush carrier in a magnetic brush contact area where the magnetic brush contacts the electrostatic latent image carrier is the same as the driving direction of the electrostatic latent image carrier, and the magnetic brush is carried in the magnetic brush contact area. This is a developing device in which the driving speeds of the drum and photoreceptor are set to be equal.

The invention according to claim 2 provides a toner image disposed at a certain gap between the electrostatic fj image on the electrostatic fjI image carrier to be driven, and to form a toner image on the electrostatic latent image carrier to be driven. A developing device comprising a plurality of drivable magnetic brush carriers each carrying a magnetic brush in contact with an electrostatic latent image carrier; The driving direction of the magnetic brush carrier in the magnetic brush contact area where the magnetic brush of the magnetic brush carrier disposed most downstream in the driving direction of the electrostatic latent image carrier contacts the electrostatic latent image carrier is controlled by the electrostatic latent image carrier. In this developing device, the driving direction is the same as that of the image bearing member, and the driving speed of the magnetic brush bearing member and the photoreceptor in the magnetic brush contact area are set to be equal.

The invention according to claim 3 provides an electrostatic latent image carrier arranged at a certain gap 4, and an electrostatic latent image on the electrostatic latent image carrier arranged at a certain gap and driven. In order to form a toner image on an electrostatic latent image bearing member, a developing sleeve is formed of toner and a carrier, and is rotatably driven while carrying a magnetic brush that contacts the electrostatic latent image bearing member, and a developing sleeve that is arranged within the developing sleeve. ,
Further, in a developing device configured by alternately disposing different magnetic poles and including 61 rotatably driven magnet members, the electrostatic latent image carrier and the magnetic brush on the developing sleeve are provided. The driving direction of the developing sleeve in the magnetic brush contact area where the magnetic brush contacts is set to be the same as the driving direction of the electrostatic latent image carrier, and the driving speed of the developing sleeve and the electrostatic latent image carrier in the magnetic brush contact area are set to be equal. and a magnetic brush regulating member is provided for regulating the magnetic brush so that the standing size of the magnetic brush on the magnetic brush carrier is larger than the gap dimension between the electrostatic latent image carrier and the developing sleeve, and a magnetic brush regulating member is provided. The rotational speed of the electrostatic latent image carrier is, however, L... In the magnetic brush contact area of the electrostatic latent image carrier VP... Linear velocity of the electrostatic latent image carrier D... Diameter of the magnet member P... of the magnet member A developing device characterized in that the number of magnetic poles Nm is set in a relationship expressed by the equation of the number of rotations of the magnet member when the rotation direction of the developing sleeve is set as positive.

The invention of claim 4 provides an electrostatic 7B image carrier arranged with a fixed gap 4, and an electrostatic latent image on the electrostatic latent image carrier with a fixed gap arranged and driven. Comprised of toner and carrier for forming a toner image on an electrostatic latent image carrier,
The developing sleeve carries and rotates a magnetic brush that contacts the electrostatic latent image carrier, and is arranged within the developing sleeve, and different magnetic poles are arranged alternately.
Moreover, in a developing device including a plurality of rotationally driven magnet members.

The driving direction of the developing sleeve in a magnetic brush contact area where the electrostatic latent image bearing member and the magnetic brush on the developing sleeve contact is the same as the driving direction of the electrostatic latent image bearing member, and furthermore, the development in the magnetic brush contact area is performed. The driving speed of the sleeve and the electrostatic latent image carrier are set to be equal, and the magnetic brush is set so that the size of the spikes of the magnetic brush on the magnetic brush carrier is larger than the gap between the electrostatic latent image carrier and the developing sleeve. A magnetic brush regulating member is provided to regulate the brush, and the number of rotations of the magnet member is, however, L... Width of the magnetic brush contact area of the electrostatic latent image carrier Vp... Linear velocity of the electrostatic latent image carrier D...Diameter of the magnet member P...Number of magnetic poles of the magnet member Nm...Set to the relationship expressed by the equation of the rotation speed of the magnet member when the rotation direction of the developing sleeve is set as positive, and further as described above. The developing device includes a rotation speed of a magnet member that changes the rotation speed of the magnet member.

(Function) According to the invention of claim 1, in the magnetic brush contact area, the magnetic brush supported on the magnetic brush carrier moves at the same speed as the driving speed of the photoreceptor while in contact with the photoreceptor. , the magnetic brush does not rub on the photoreceptor.

According to the invention of claim 2, in the magnetic brush contact area of the magnetic brush carrier disposed at the most downstream position in the driving direction of the electrostatic latent image carrier, the magnetic brush carried by the magnetic brush carrier is The magnetic brush moves at the same speed as the driving speed of the electrostatic latent image carrier while in contact with the electrostatic latent image carrier, and the magnetic brush does not rub on the electrostatic latent image carrier.

According to the third aspect of the invention, the magnetic brush regulating member regulates the standing size of the magnetic brush on the developing sleeve to be larger than the gap between the electrostatic latent image carrier and the developing sleeve. The magnetic brush fills the magnetic brush contact area and in this state vibrates due to the rotation of the magnet member.

According to the invention of claim 4, the magnetic brush regulating member regulates the standing size of the magnetic brush on the developing sleeve to be larger than the gap between the electrostatic latent image carrier and the developing sleeve. The magnetic brush fills the magnetic brush contact area and in this state vibrates due to the rotation of the magnet member. Furthermore, the rotation speed of the magnet member is changed depending on the rotation speed of the magnet member.

(Example) The present invention will be explained in detail below. The developing devices according to the following examples are all installed in a copying machine.

Regarding an embodiment corresponding to the invention of claim 1, FIG.
This will be explained based on the drawings of Fig. 1Δ and Fig. 2.

In the figure, reference numeral 18 indicates a photoreceptor as an electrostatic latent image carrier. The photoreceptor 18 is configured to rotate clockwise, and an electrostatic latent image is formed on the photoreceptor 18 by a device not shown.

Reference numeral 12.13 indicates a developing sleeve, and this developing sleeve 12.13 is arranged opposite to the photoreceptor. The developing sleeves 12 and 13 are housed in a casing 20, and a portion facing the photoreceptor 18 is exposed through an opening 20a of the casing 20. Developing sleeve 12 and photoreceptor 18
A magnetic brush contact area E is located in the opposing area between the developing sleeve 13 and the photoreceptor 18, and a magnetic brush contact area F is located in the opposite area between the developing sleeve 13 and the photoreceptor 18.
is formed.

The developing sleeves 12, 13 are adapted to rotate clockwise. The number of rotations of the developing sleeve 12.13 is such that the number of rotations of the developing sleeve 12.13 varies in the magnetic brush contact areas E and F.
The driving speed of photoreceptor 13 and the driving speed of photoreceptor 18 are set to be equal.

A magnet fixed to a stationary member is arranged inside the developer sleeve 12.13. A magnetic brush B made of carrier and toner is supported on the developing sleeve 12.13 by the magnetic field of this magnet.

The casing 2 is attached to the upper end of the opening 21a of the casing 20.
A doctor 15 is provided which is formed by bending a part of 0. Reference numeral 14 indicates a shielding scraping member, and the edge of this shielding scraping member 14 is in contact with the circumferential surface of the developing sleeve 13 .

This shielding scraping member 14 serves to scrape off other agents from the top of the developing sleeve 13 after the developing operation, and also to scrape off other agents from the developing sleeve 13.
Third, it serves to prevent developer from being supplied from the rear region of the sleeve.

In the rear region of the developer sleeve 12.13 within the casing 20 there is a transport paddle 11. A guide plate 16 and a conveyance screw 17 are provided.

Next, this curse 9. The operation of the device will be explained.

The photoreceptor 18 rotates clockwise, and an electrostatic latent image is formed on the photoreceptor 18 by a device (not shown).

On the other hand, the conveying paddle 11 of the developing device 19 rotates clockwise and conveys the developer consisting of carrier and toner inside the casing 20 along the path indicated by the arrow.

Then, the other agent is supplied onto the developing sleeve 12 which rotates counterclockwise and is carried on the sleeve 12. The developer on this sleeve 12 is regulated to a constant height by a doctor 15, and a magnetic brush B having a constant spike height is formed on the developing sleeve 12. At this time, the excess developer moves toward the stirring screw 17 along the guide plate 16 as shown by the arrow.

The magnetic brush B on the developing sleeve 12 contacts the photoreceptor 18 in the magnetic brush contact area E, toner is supplied to the electrostatic latent image on the photoreceptor 18, a developing operation is performed, and the toner is applied to the electrostatic latent image on the photoreceptor 18. A toner image is formed on.

After the developing operation by the developing sleeve 12, the developer forming the magnetic brush B on the sleeve 12 leaves the sleeve 12 and moves onto the developing sleeve 13.
Magnetism B is formed on top. Then, the magnetic brush B on the sleeve 13 operates in the same manner as the sleeve 12 to supply toner to the toner image on the photoreceptor 18-L.

As mentioned above, the rotational speed of the developing sleeve 12.13 in the magnetic brush contact areas E and F is
The driving speed of the photoreceptor 18 is set to be equal to the driving speed of the photoreceptor 18. Therefore, in the above-mentioned developing operation, as shown in FIG. 1A, the magnetic brush B in a certain range shown by the solid line on the developing sleeve 12.13 remains in contact with the photoreceptor 18 without rubbing the photoreceptor 18. Moving.

Therefore, the magnetic brush B once in contact with the background part of the photoreceptor 18
is prevented from coming into contact with the electrostatic latent image on the photoreceptor 18 again.

The developing device 29 shown in FIG. 2 has the developing sleeves 12 and 13 separated into separate units.

Since the developing device 29 has common features in configuration and operation with the developing device 19 shown in FIG. 1, only the differences between the developing device 29 and the developing device 19 will be described, and members that perform the same function will be described. are given the same reference numerals as in FIG. 1, and their explanation will be omitted.

The developing sleeve 12 is housed in a casing 30,
A portion of the developing sleeve 12 facing the photoreceptor 18 is exposed through the opening 30a of the casing 30. In the rear region of the developing sleeve 12 inside the casing 30, a guide plate 16, a conveyance paddle 11, and a stirring screw 17 are arranged.

The developing sleeve 13 has the same #! casing 30 that houses the developing sleeve 12. Housed in a built-in casing,
Further, since each device inside the casing is the same as that arranged inside the casing 30, the description of the casing housing the developing sleeve 13, etc.
The same reference numerals as those for the casing, etc. that house the are given, and their explanation will be omitted.

Next, the operation of the developing device 29 will be explained.

In the magnetic brush contact area E, the magnetic brush B on the developing sleeve 12 contacts the photoreceptor 18, supplies toner to the electrostatic latent image on the photoreceptor 18, performs a developing operation, and then transfers the toner onto the developing sleeve 13. A magnetic brush B contacts the toner image on the photoreceptor 18 and further supplies toner.

Also in the developing device 29, the developing sleeves 12, 13 perform the same operation as explained with reference to FIG. 1A in the above-mentioned developing operation.

An embodiment corresponding to claim 3 will be described based on FIG. 3.

The developing device 39 shown in the same figure is the developing device 1 shown in FIG.
9, the same components as the developing device 19 are designated by the same reference numerals as in FIG.
The explanation will be omitted.

The developing sleeves 42 and 43 are disposed to face the photoreceptor 18, and the developing sleeve 42 and the developing sleeve 43 are rotated clockwise and counterclockwise, respectively. Q&
The rotational speed of the sleeve 43 is set so that the driving speed of the developing sleeve 43 in the magnetic brush contact area F and the driving speed of the photoreceptor 18 are equal.

Magnets (not shown) are provided inside the developing sleeves 42 and 43. A magnetic brush B made of carrier and toner is supported on the developing sleeves 42 and 43 by the magnetic field of this magnet.

A doctor 44 is arranged between the developing sleeve 42 and the developing sleeve 43. Reference numeral 46 indicates a guide plate;
The edge of this guide plate 46 is in contact with the circumferential surface of the developing sleeve 42 .

The operation of the developing device 39 will be explained.

The conveyance paddle 11 rotates counterclockwise, and the casing 2o
A developer consisting of a carrier and toner is supplied onto a rotating developing sleeve 42.43, and
3. The developer on the sleeves 42, 43 is regulated to a constant height by a doctor 44, and a magnetic brush B having a constant spike height is formed on the developing sleeves 42, 43.

In the magnetic brush contact area E, toner is supplied by the magnetic brush B on the developing sleeve 42 to the electrostatic latent image on the photoreceptor 18 rotating once clockwise.

The current fI4 operation is performed to form images 1 to 4 on the photoreceptor 18, and the photoreceptor 18 further rotates clockwise. Further toner is further supplied to the toner on the photoreceptor 18 by the magnetic brush B of the developing sleeve 43''.

The developing sleeve 43 performs the same operation as that described in FIG. 1A, and the magnetic brush B on the developing sleeve 42
5. Supply toner to the blank areas that occur during the developing operation.

Note that the developing device 39 is also similar to the developing device 2 shown in FIG.
It is also possible to make the developing sleeves 42 and 43 into separate units as shown in FIG.

An embodiment corresponding to claim 3 will be described based on FIG. 4.

The developing device of this embodiment includes the developing device 39 shown in FIG.
Since they have common constituent parts, only the main parts that are different in structure will be shown, and the explanation of other constituent parts will be omitted.

In FIG. 4, reference numeral 54 indicates a developing sleeve, and this developing sleeve 54 is designed to rotate counterclockwise. The rotational speed of the developing sleeve 54 is set so that the driving speed in the magnetic brush contact area E is equal to the driving speed of the photoreceptor 18.

A magnetic roller 56 is provided inside the developing sleeve 54 as a magnetic member in which magnetic poles are arranged alternately.
This magnetic roller 56 is designed to rotate clockwise. A magnetic brush B made of carrier and toner is supported by the magnetic field of the magnet roller 56.

Reference numeral 52 denotes a doctor, and this doctor 52 adjusts the standing dimensions of the magnetic brush B between the photoreceptor 18 and the developing sleeve 56.
The gap is regulated to be larger than the gap dimension α. Reference numeral 57 indicates a scraper, and the edge of this scraper 57 is in contact with the circumferential surface of the developing sleeve 54.

The moving linear velocity of the photoconductor 18 is vp (mm/5ee), and the rotation speed of the magnetic roller 56 is Nm (rpu+ ) (the direction shown is negative), the diameter of the magnetic roller 56 is D (m+n),
When the number of magnetic poles of the magnetic roller 56 is P and the linear velocity of movement of the magnetic roller 56 is V m (mm/5ee), the photoreceptor 1
8 passes through the magnetic brush contact area E of Lmm, the number of magnetic poles of the magnetic roller 56 that also passes through the area is determined in a linear manner.

The time it takes for the photoreceptor 18 to pass through the magnetic brush contact area E having L+am is: (1) In the magnetic brush contact area E, one magnetic pole of the magnet roller 56 faces the photoreceptor 18, and then the next magnetic pole faces the photoreceptor 18. How long will it take?

Ideally, if the settings are made to satisfy the following, the following effects will occur.

Next, the operation of the developing device of this embodiment will be explained.

A developer consisting of carrier and toner is supplied onto the developing sleeve 54 by the conveying paddle, and the developer is supplied onto the developing sleeve 54.
4. Then, the developer on the sleeve 54
The magnetic brush Ba is regulated by the doctor 52 to be slightly larger than the gap size α between the photoreceptor 18 and the developing sleeve 54, and has a constant bristled size.

The developing sleeve 54 rotates counterclockwise, and the magnetic brush B
a is conveyed to the magnetic brush contact area E, and the magnetic brush Ba on the developing sleeve 54 comes into contact with the photoreceptor 18 in the same manner as described in FIG. 1A.

As mentioned above, since the magnetic brush Ba has a spike size larger than the gap size α, the magnetic brush Ba has a state in which the magnetic brush contact area E is filled with the developer constituting the magnetic brush Ba. Become.

Then, the plurality of alternately arranged magnetic poles pass through the magnetic brush contact area E due to the above-described predetermined rotational movement of the magnet roller 56. Therefore, the developer constituting the magnetic brush Ba vibrates randomly and violently. This vibration weakens development resistance such as intermolecular force acting between the carrier and the toner constituting the developer, making it easier for the toner to separate from the carrier. Therefore, the amount of toner supplied to the electrostatic latent image on the photoreceptor 18 is increased, and the developing ability of the apparatus is improved.

In the above-mentioned development operation, in order to sufficiently vibrate the developer constituting the magnetic brush Ba and prevent uneven development, the magnetic roller Ideally, five or more of the 56 magnetic poles would pass through the magnetic brush contact area E.

An embodiment corresponding to claim 4 will be described.

The developing device whose main parts are shown in FIG. 5 has the same structure as the developing device shown in FIG. 4, except for the particular difference in the rotation speed of the magnet member, so the parts related to the same structure are shown in FIG. 4. The same reference numerals will be used to omit the explanation of the structure and operation.

The magnetic roller 56 is rotated clockwise by a variable speed motor.

Reference numeral 6o indicates a magnet roller rotation speed switching device for changing the rotation speed of the magnet member, and this rotation switching device 60 is connected to a variable speed motor that rotates the magnet roller 56.

The operation of the developing device of this embodiment will be explained.

The rotation speed of the magnet roller 56 is changed by the rotation speed switching means 60, and while the photoreceptor 18 passes through the magnetic brush contact area E, the number of magnetic poles of the magnet roller 56 passing through the area E is changed, thereby forming the magnetic brush Ba. Adjust the vibration state of the developer.

By adjusting the vibration state of the developer in this way, the development resistance such as the intermolecular force between the carrier and toner that constitute the developer is controlled, and the toner is moved to a static state on the photoreceptor 18 as shown in the graph of FIG. By adjusting the amount supplied to the electrostatic latent image, the developing ability of the developing device is changed.

In the above embodiments, the effects of the present invention can be achieved if the linear velocity ratio between the photoreceptor and the developing sleeve is in the range of 1:0.8 to 1.2.

Although each of the above embodiments uses a drum-shaped photoreceptor, the present invention is not limited thereto, and a belt-shaped photoreceptor may also be used.

The present invention is not limited to the case where it is applied to the above-mentioned copying machine, but may be applied to various types of printers.

(Effects of the Invention) As described above, according to the present invention, it is possible to prevent the occurrence of so-called solid cross white spots, and to obtain an image with sufficient density.

Furthermore, according to the fourth aspect of the invention, it is possible to freely change both fgl'a degrees.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a developing device of an embodiment corresponding to claim 1, FIG. 1A is a diagram for explaining the developing operation of the developing device of the present invention, and FIG. FIG. 3 is a diagram showing a developing device of another corresponding embodiment; FIG. 3 is a diagram showing a developing device of an embodiment corresponding to claim 2; FIG. 4 is a developing device of an embodiment corresponding to claim 3. FIG. 5 is a diagram showing the main parts of the apparatus, FIG. 5 is a diagram showing the main parts of an embodiment corresponding to claim 4, FIG. 6 is a diagram for explaining the operation of the developing device according to claim 4, 12.13.42.43.54...Developing sleeve, 1
8... Photoreceptor, 52... Doctor, 56... Magnet roller, 60... Magnet roller rotation speed switching device) Illusion t! ! Chi Z area r A diagram v) 4th 'I'yf-) 5 area 1 70 most q illusion most illusion 1 O area

Claims (1)

[Claims] 1. Toner is supplied to an electrostatic latent image on a driving electrostatic latent image carrier for development, and the toner and carrier are combined to form a toner image on the electrostatic latent image carrier. A developing device comprising a plurality of driveable magnetic brush carriers each carrying a magnetic brush in contact with an electrostatic latent image carrier, wherein the magnetic brush contacts the electrostatic latent image carrier. The driving direction of the magnetic brush carrier in the magnetic brush contact area is the same as the drive direction of the electrostatic latent image carrier, and the driving speeds of the magnetic brush carrier and the photoreceptor in the magnetic brush contact area are set to be equal. A developing device characterized by: 2. Toner is supplied to the electrostatic latent image on the electrostatic latent image carrier to perform development, and to form a toner image on the electrostatic latent image carrier, the electrostatic latent image is composed of toner and carrier. In a developing device including a plurality of magnetic brush carriers that carry magnetic brushes in contact with an image carrier and are freely drivable, one of the plurality of magnetic brush carriers in the driving direction of the electrostatic latent image carrier The driving direction of the magnetic brush carrier disposed at the most downstream position in the magnetic brush contact area where the magnetic brush contacts the electrostatic latent image carrier is the same as the drive direction of the electrostatic latent image carrier. A developing device characterized in that the driving speeds of the magnetic brush carrier and the electrostatic latent image carrier in the magnetic brush contact area are set to be equal. 3. Developing the electrostatic latent image by supplying toner to the electrostatic latent image on the electrostatic latent image carrier, which is arranged with a certain gap between the electrostatic latent image carrier and being driven, and then developing the electrostatic latent image on the electrostatic latent image carrier In order to form a toner image, there is a developing sleeve which is made of toner and a carrier and is rotatably driven while carrying a magnetic brush that contacts an electrostatic latent image carrier, and a developing sleeve which is arranged inside this developing sleeve and in which different magnetic poles are arranged alternately. In the developing device, which is configured to have a plurality of rotatably driven magnet members, the developing device is provided with a magnetic brush contact area where the electrostatic latent image carrier and the magnetic brush on the developing sleeve come into contact with each other. The driving direction of the sleeve is the same as the driving direction of the electrostatic latent image carrier, and the driving speeds of the developing sleeve and the electrostatic latent image carrier in the magnetic brush contact area are set to be equal, and the electrostatic latent image carrier and A magnetic brush regulating member is provided to regulate the magnetic brush so that the size of the magnetic brush on the magnetic brush carrier is larger than the gap with the developing sleeve, and the number of rotations of the magnet member is (LP | V_P −(πD/60)Nm|/πDV_P)
≧2 However, L...Width of the magnetic brush contact area of the electrostatic latent image carrier V_P...Linear velocity of the electrostatic latent image carrier D...Diameter of the magnet member P...Number of magnetic poles of the magnet member Nm . . . A developing device characterized by being set to a relationship expressed by an equation of the rotational speed of the magnet member when the rotational direction of the developing sleeve is set as positive. 4. Developing the electrostatic latent image by supplying toner to the electrostatic latent image on the electrostatic latent image carrier, which is arranged with a certain gap between the electrostatic latent image carrier and the moving electrostatic latent image carrier. In order to form a toner image, there is a developing sleeve which is made of toner and a carrier and is rotatably driven while carrying a magnetic brush that contacts an electrostatic latent image carrier, and a developing sleeve which is arranged inside this developing sleeve and in which different magnetic poles are arranged alternately. In the developing device, which is configured to have a plurality of rotatably driven magnet members, the developing device is provided with a magnetic brush contact area where the electrostatic latent image carrier and the magnetic brush on the developing sleeve come into contact with each other. The driving direction of the sleeve is the same as the driving direction of the electrostatic latent image carrier, and the driving speeds of the developing sleeve and the electrostatic latent image carrier in the magnetic brush contact area are set to be equal, and the electrostatic latent image carrier and A magnetic brush regulating member is provided to regulate the magnetic brush so that the size of the magnetic brush on the magnetic brush carrier is larger than the gap with the developing sleeve, and the number of rotations of the magnet member is (LP | V_P −(πD/60)Nm|/πDV_P)
≧2 However, L...Width of the magnetic brush contact area of the electrostatic latent image carrier V_P...Linear velocity of the electrostatic latent image carrier D...Diameter of the magnet member P...Number of magnetic poles of the magnet member Nm . . . Set to a relationship expressed by the equation of the rotation speed of the magnet member when the rotation direction of the developing sleeve is set as positive, and further comprising a magnet member rotation control means for switching the rotation speed of the magnet member. A developing device.