JP2002006622A - Developing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device and an image forming device in which a developer is prevented from scattering from a nip between a developer carrier and a developer regulating member. SOLUTION: Starting torque (T) needed for starting the rotation of a developing sleeve (sleeve) 110 from a stationary state is larger than the maximum torque (μmax.P.r) that is transmitted to the sleeve 110 side when a developer regulating roller (roller) 130 is rotated; therefore, the sleeve 110 is prevented from rotating with the roller 130. As a result, when the roller 130 rotates, its surface slides rotatably with the surface of the sleeve 110, thereby crushing and pulverizing a compressed aggregated lump of the developer which exists in a wedge part on the upstream side in the surface moving direction of the sleeve 110 in the nip between the sleeve 110 and the roller 130.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device and an image forming apparatus used for an image forming apparatus such as a copying machine, a facsimile, a printer, and the like. A developer regulating member that regulates the upper developer layer to form a fixed amount of developer layer is formed in a roller shape, and the developer regulating member is driven to rotate by a predetermined angle in a state where the developing carrier is not driven. The present invention relates to an apparatus and an image forming apparatus.

[0002]

2. Description of the Related Art Heretofore, there has been known a developing device using a regulating blade as a developer regulating member for regulating an amount of developer carried on a developer carrying member of a developing device. FIG. 9 is a schematic configuration diagram illustrating an example of a conventional developing device. The developing device includes a developer carrier 2, a developer supply member 3, a regulating blade 4, a developer hopper 5, and three developer transport members 6.
a, 6b, 6c and a discharge paddle 7. The regulating blade 4 is a cantilever having a one-sided support and a one-sided free end, and the free end is pressed against the developer carrier 2. The amount of the developer attached to the surface of the developer carrier 2 by the developer supply member 3 is reduced by the narrow entrance shape formed by the tip of the regulating blade 4 and the developer carrier 2 and the contact pressure of the regulating blade 4. And the amount that goes out is regulated. The developer is composed of a developer carrier 2 and a regulating blade 4.
When passing through the abutting portion, the developer layer is subjected to frictional charging, and a developer layer having a uniform and stable charge is formed and sent to the developing portion. The developer scraped off by the developing blade 4 is returned to the hopper 5 by the discharge paddle 7.

However, since the regulating blade 4 is always in contact with the developer carrier 2 at the same position, clogging of the regulating blade 4 with foreign matters and fixing of the developer or the like occur in a relatively short time. . Then, the image formed by transferring the developer from the developing device to the image carrier of the main body of the image forming apparatus will have uneven streaks and stains on the background. Once these abnormalities occur, it is difficult to recover. As described above, the developing device using the regulating blade has a simple structure, but has a limited life, and the image quality is maintained by performing frequent replacement of the developing device.

As described above, since the developing device using the regulating blade has a short device life, the regulating blade cannot be used in a high-speed machine layer in which image quality stability is required for a long time. Therefore, a device using a roller-shaped developer regulating member instead of the regulating blade has been proposed. For example, in JP-A-9-80905,
A method is disclosed in which a roller-shaped developer regulating member is driven to rotate with respect to a developer carrier to regulate the amount of developer. By doing so, the occurrence of the above-described clogging of the foreign substances and the sticking of the developer can be suppressed. However, when the developer carrier and the developer regulating member are rotated in the same direction, in the nip where the two members come into contact, the two members always drive in the opposite direction, and the two members are strongly rubbed. A large amount of torque is required, and there is a problem that restrictions are increased, such as a structure of a motor having a large torque and a developing device having sufficiently high strength. Further, there is also a problem that vibration and noise are likely to be generated due to an increase in the frictional force of the nip, and that the regulation of the developer may not be performed well. Similarly, there is a problem in that heat is generated in the nip with an increase in frictional force, giving thermal stress to the developer, and the developer is likely to be fixed to the developer carrier or the developer regulating member. Therefore, additional design such as prevention of heat radiation and vibration is required, and the size of the developing device is further increased.

As a technique for solving the above problem, there is a technique disclosed in Japanese Patent Application Laid-Open No. 11-84867. According to this technique, the rotation drive transmission between the developer carrying member and the developer regulating member is provided as a separate system, and when the developer carrying member is rotating, the developer regulating member is stopped and a certain amount of the developer layer is stopped. Is formed, and the developer regulating member is moved by a predetermined angle or a predetermined number of revolutions when the developer carrier is stopped. Thereby, when the developer carrying member is rotating and performing the developing operation, the developer regulating member can form the developer layer by the same action as the regulating blade, and the developer regulating member can be moved simultaneously with the developer carrying member. As compared with the case of rotating, the rotating torque can be small, and the generation of vibration and noise can be reduced. Further, by rotating the developer regulating member when the developer carrier is stopped,
Foreign matter caught in the gap can be removed. In addition, by moving the contact position of the developer regulating member with the developer carrier as needed, it is possible to prevent the developer from sticking to the surface of the developer regulating member.

[0006]

At the upstream side of the nip between the developer carrier and the developer regulating member in the direction of movement of the surface of the developer carrier, a space formed by the surface of a roller having a curvature of both members (hereinafter, referred to as a space). "Wedges"). In the wedge portion, there is a lump of the compressed and agglomerated developer caused by the regulation of the developer. In the technique disclosed in Japanese Patent Application Laid-Open No. H11-84867, if the developer carrier is freely rotatable during a non-development operation, the developer regulating member may rotate with the rotation of the developer regulating member. Then, the lump of the compressed and agglomerated developer existing in the wedge portion is moved to the upstream side of the nip while being temporarily attached to the surface of the developer carrier by the rotating operation of the developer carrier without being broken. . FIG. 6 is an explanatory diagram of a state in which a mass of the developer that has been compressed and aggregated adheres to the surface of the developer carrier.

If a mass of the compressed and agglomerated developer adheres to the surface of the developer carrying member, the mass of the compressed and agglomerated developer becomes large when the developer carrying member starts rotating in the next developing operation. Enters the nip with the developer regulating member, and the developer layer is temporarily disturbed. Since the disturbance of the developer layer occurs in a relatively short time from the start of rotation, the influence on the image can be reduced by shifting the image forming timing on the image carrier. However, there is a problem that the compressed and agglomerated developer mass scatters when passing through the nip with the developer regulating member. Since the developer is compressed, it is not sufficiently loosened even when passing through the nip, and comes out as it is. For this reason, it is considered that the toner is hardly charged and the adhesive force to the surface of the developer carrying member is not sufficient, and the toner scatters. The greater the number of times the developer regulating member is rotationally driven to prevent sticking and remove foreign matter, the more the developer is scattered in the image forming apparatus main body, which adversely affects the image forming operation. For example, the scattered developer adheres to the transfer paper to stain the transfer paper, or enters a drive transmission member such as a clutch to cause banding due to abnormal drive transmission.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide a developing device and an image forming apparatus in which a developer does not scatter from a nip between a developer carrier and a developer regulating member. It is to provide.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, a developer is adhered to an image carrier while rotating or rotating in close proximity to or in contact with the image carrier. A developer carrier for forming an image, supply means for supplying the developer to the developer carrier, and a fixed amount of a developer layer which is in contact with the developer carrier and regulates the developer layer on the developer carrier. In a developing device having a developer regulating member serving as a developer layer, the developer regulating member is formed in a roller shape, and the developer regulating member is driven to rotate by a predetermined angle in a state where the development carrier is not driven. T has a rotation driving means, the starting torque required for the developer carrier to start rotating from a stationary state is T, the maximum static friction coefficient between the developer regulating member and the developer carrier is μmax, The pressure applied between the developer regulating member and the developer carrier is P The distance from the rotation center of the developing bearing member to the surface when the r, is characterized in satisfying the relation T> μmax · P · r.

[0010] If the developer carrying member rotates along with the rotation of the developer regulating member, the nip between the developer carrying member and the developer regulating member is located on the upstream side in the moving direction of the surface of the developer carrying member. The mass of the compressed and agglomerated developer present in the wedge portion is divided on both sides of the developer carrier and the developer regulating member, and adheres to the surface of the developer carrier and the surface of the developer regulating member, respectively. To move. Then, when the developer carrier passes through the nip in the next developing operation, the lump of the developer attached to the surface of the developer carrier is scattered. In this developing device, the starting torque ("T") required for the developer carrier to start rotating from a stationary state is transmitted to the developer carrier when the developer regulating member rotates. Drive torque ("μma
x · P · r ”), the developer carrier does not rotate with the rotation of the developer regulating member. Therefore, when the developer regulating member rotates, the surface of the developer regulating member slides and rotates with the surface of the developer carrying member, and a nip between the developer carrying member and the developer regulating member. The agglomeration of the compressed and agglomerated developer existing in the wedge portion on the upstream side in the direction of movement of the surface of the developer carrying member is broken and reduced to fine particles. Therefore, the mass of the developer does not adhere to the surface of the developer carrier, and the developer does not scatter from the nip during the next developing operation.

According to a second aspect of the present invention, in the developing device of the first aspect, the supply means is configured by using a supply member for supplying the developer in contact with the developer carrier, and A drive transmitting means for transmitting the driving force and a drive transmitting means for transmitting the driving force of the supply member are connected.

In this developing device, the driving force transmitting means for transmitting the driving force of the developer carrier and the driving force transmitting means for transmitting the driving force of the supply member are connected to each other. The starting torque T required for the developer carrier to start rotating from a stationary state is smaller than that when the drive transmitting means for transmitting the driving force is not connected. The required starting torque is also weighted. Therefore, the starting torque T becomes larger than when there is no such weight, and accordingly, μmax, P, and r that satisfy the above relationship can be made larger. Therefore, for example, by increasing μmax or P, it is possible to more efficiently regulate the developer. When the developer is a one-component developer, the charge amount can be further increased. In addition, if the developer carrier is a roller, increasing r increases the area of the developer carrier, so that a predetermined amount of developer can be transported even when the number of rotations is reduced. The durability of the developer carrier can be improved.

According to a third aspect of the present invention, in the developing device of the second aspect, the supply member has a foam material on a surface thereof, and the hardness (Asker C) of the supply member is 5 degrees or more and 30 degrees. Or less, and the cell diameter of the foamed material is 0.05 [mm] or more and 0.5 or more.
[mm] or less.

If the hardness of the supply member is lower than 5 [degrees], the contact pressure against the developer carrier decreases, and the frictional force at the contact portion becomes insufficient. On the other hand, if the hardness is higher than 30 [degrees], the contact pressure becomes excessive to secure a predetermined nip width between the supply member and the developer carrying member, and the driving torque during the developing operation increases. If the cell diameter of the foamed material is smaller than 0.05 [mm], the developer supply and supply power is insufficient, and the condition as a supply member cannot be satisfied. On the other hand, when the cell diameter is larger than 0.5 [mm], the contact area with the developer carrier is small, so that the frictional force at the contact portion is insufficient. Further, toner clogging is liable to occur, and the conveyance supply power is reduced with time.
In this developing device, the hardness of the supply member (Asker C)
Is not less than 5 [degrees] and not more than 30 [degrees], and the cell diameter on the surface of the foam material is not less than 0.05 [mm] and not more than 0.5 [mm]. There is no shortage of frictional force at the contact portion with respect to the carrier. Also, during the developing operation, the driving torque of the supply member does not increase,
In addition, the developer conveyance supply force can be maintained.

According to a fourth aspect of the present invention, in the developing device of the first aspect, a developer accommodating portion for accommodating the developer, and at least one developer for conveying the developer from the developer accommodating portion to the supply means. And a drive transmitting means for transmitting the driving force of the developer carrying member, and a drive transmitting means for transmitting the driving force of the developer conveying member.

In this developing device, the drive transmitting means for transmitting the driving force of the developer carrier and the drive transmitting means for transmitting the driving force of the developer conveying member are connected to each other. The starting torque T required for the developer carrier to start rotating from a stationary state is smaller than when the drive transmitting unit for transmitting the driving force of the member is not connected.
The starting torque required to start the rotation of the developer conveying member from the stationary state is also weighted. Therefore, as compared with the case where there is no such weight, the starting torque T
Becomes larger, and accordingly,
x, P, and r can be made larger. Therefore, for the same reason as described in the second aspect, the regulation of the developer can be performed more efficiently. When the developer is a one-component developer, the charge amount can be further increased. Further, the durability of the developer carrier can be improved.

According to a fifth aspect of the present invention, in the developing device of the first aspect, the supply means is constituted by using a supply member for supplying the developer in contact with the developer carrier, and stores the developer. A drive transmitting unit that has a developer accommodating portion, and at least one developer conveying member that conveys the developer from the developer accommodating portion to the supply member, and that transmits a driving force of the developer carrier; A drive transmitting means for transmitting the driving force of the supply member and a drive transmitting means for transmitting the driving force of the developer conveying member are connected.

In this developing device, a driving force transmitting means for transmitting the driving force of the developer carrier, a driving force transmitting means for transmitting the driving force of the supply member, and a driving force for transmitting the driving force of the developer conveying member. Since the transmission means is connected, compared to a case where these drive transmission means are not connected,
The starting torque T required to start the rotation of the developer carrier from the stationary state is obtained by adding the starting torque required to start the rotation of the supply member and the developer conveying member from the stationary state. Becomes Therefore, the starting torque T becomes larger than when there is no such weight, and accordingly, μmax, P, and r that satisfy the above relationship can be made larger. Therefore, for the same reason as described in the second aspect, the regulation of the developer can be performed more efficiently. When the developer is a one-component developer, the charge amount can be further increased. Further, the durability of the developer carrier can be improved.

According to a sixth aspect of the present invention, in the developing device of the first aspect, at least one surface of the developer carrier or the developer regulating member has a fluororesin, a polyamide resin, a urethane resin, a melamine resin, It is characterized by being composed of guanamine resin, stainless steel, electroless Ni plating, aluminum or aluminum alumite.

Fluororesin, polyamide resin, urethane resin, melamine resin, guanamine resin, stainless steel, electroless Ni plating, aluminum and aluminum alumite
Normally, the coefficient of static friction is smaller than the material forming the surface portion of the developer carrier or the developer regulating member, for example, urethane rubber or NBR. In this developing device, at least one surface of the developer carrier or the developer regulating member has a fluororesin, a polyamide resin, a urethane resin,
Melamine resin, guanamine resin, stainless steel, electroless N
Since it is made of i-plated, aluminum or aluminum alumite, the maximum static friction coefficient μmax between the developer carrier and the developer regulating member can be made smaller than when it is not made of the fluororesin or the like. Accordingly,
P and r that satisfy the above relationship can be made larger. Therefore, for the same reason as described in claim 2, if the developer is a one-component developer, the charge amount can be further increased. Further, the durability of the developer carrier can be improved.

According to a seventh aspect of the present invention, in the developing device of the first or sixth aspect, particles having an average particle size of 0.5 [μm] or less are externally added to the periphery of the colored particles as a component of the developer. It is characterized by having.

According to an experiment, when particles having an average particle size of 0.5 [μm] or less are externally added to the periphery of the colored particles as a component of the developer, the fluidity of the developer is improved. This has the effect of reducing the frictional force between the developer carrier and the developer regulating member. On the other hand, if the particle diameter of the particles exceeds 0.5 [μm], the fluidity of the developer is rather inhibited, and the frictional force between the developer carrier and the developer regulating member increases. In this developing device, particles having an average particle size of 0.5 [μm] or less are externally added to the periphery of the colored particles as constituents of the developer, so that the fluidity of the developer is improved, Since the frictional force between the developer carrier and the developer regulating member is reduced, r that satisfies the above relationship can be increased accordingly.
Therefore, for the same reasons as described above for claim 2,
The durability of the developer carrier can be improved.

According to another aspect of the present invention, there is provided a latent image carrier for carrying a latent image of an image on a surface thereof, a developing device for developing the latent image with a developer, and a transfer material on which the developed image is transferred. In the image forming apparatus having the above configuration, the developing device according to any one of claims 1 to 7 is used as the developing device.

In this image forming apparatus, the developer can be prevented from scattering from the nip between the developer carrier and the developer regulating member during the developing operation of the developing device. And the inside of the apparatus main body can be prevented.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] An example of an embodiment in which the present invention is applied to an electrophotographic color printer (hereinafter, referred to as a color printer) as an image forming apparatus will be described. First, the schematic configuration and operation of the color printer according to the present embodiment will be described with reference to FIG. The color printer 1 includes a photoreceptor unit 10, a writing optical unit 20, a developing unit 30, an intermediate transfer unit 40, a secondary transfer unit 50, a fixing unit 60, a double-sided printing paper reversing unit 70, and the like. Black: black (hereinafter referred to as Bk), Cyan:
Cyan (hereinafter referred to as C), Magenta: Magenta (hereinafter referred to as M), Yellow: Yellow (hereinafter referred to as M)
Y) is sequentially visualized on the photoreceptor belt 11 of the photoreceptor unit 10, and these are superimposed to form a final four-color full-color image.

The photoreceptor belt 11 rotates clockwise as indicated by an arrow A. Around the photoreceptor cleaning device 1
2, a charging roller 13, a selected developing unit of the developing unit 30, an intermediate transfer belt 41 of the intermediate transfer unit 40, and the like. The photoreceptor belt 11 includes the driving roller 1
4, which is stretched between the primary transfer facing roller 15 and the stretching roller 16 and is rotated in the direction of arrow A by a drive motor (not shown). When the photoconductive belt 11 having a seam is used, a seam mark is provided in a non-image forming area at the end of the photoconductive belt 11, detection is performed by a sensor (not shown), and an image is formed avoiding the seam.

The writing optical unit 20 is
The color image data is converted into an optical signal, optical writing corresponding to each color image is performed, and an electrostatic latent image is formed on the photosensitive belt 11. The writing optical unit 20 includes a semiconductor laser as a light source, a laser emission drive control unit (neither is shown), a polygon mirror 22, and three reflection mirrors 23.
a, b, c, etc.

The developing unit 30 includes a Bk developing unit 31K, a C developing unit 31C, an M developing unit 31M, and a Y developing unit 31Y. It is configured by a contact / separation mechanism (not shown) that performs a separating operation. In each of the developer storage cases 32K, C, M, and Y of each of the developing devices 31K, C, M, and Y, a one-component developer including a toner of each color is stored as a developer. In the illustrated example, a Bk developing unit 31K containing black toner and a C containing cyan toner are arranged in order from the lower side of the apparatus main body.
Developing device 31C, M developing device 31 containing magenta toner
This is a Y developing device 31Y containing M and yellow toner. The contact / separation mechanism activates an electromagnetic solenoid (not shown) so that the developer accommodating case 32K, C, M, Y
Is moved toward the photoreceptor belt 11 (left side in the figure). At the time of development, any one of the developing devices 31K, C, M, and Y moves, and the photosensitive belt 1
Contact 1 On the other hand, when the electromagnetic solenoid is turned off, the developing device that has been in contact with the photoreceptor belt 11 is moved in the direction away from the photoreceptor belt 11 (right side in the figure) by a return spring built in the electromagnetic solenoid. The developing devices 31K, C, M, and Y will be described later in detail.

In the standby state of the color printer main body, the developing unit 30 is set at a position where all the developing units 31K, C, M, and Y are separated from the photosensitive belt 11, and when the printing operation is started, the developing unit 30 is set to the color mode. Optical writing with a laser beam and formation of an electrostatic latent image are started based on the image data (hereinafter, an electrostatic latent image based on Bk image data is referred to as a Bk electrostatic latent image. The same applies to C, M, and Y). Before the front end of the electrostatic latent image reaches the Bk development position to enable development from the front end of the Bk electrostatic latent image, the rotation of the developing sleeve 110 is started to develop the Bk electrostatic latent image with Bk toner. I do. Thereafter, the developing operation of the Bk electrostatic latent image area is continued.
When the trailing edge of the electrostatic latent image passes the Bk development position, Bk
The developing device 31K is separated from the photosensitive belt 11, and the developing device of the next color immediately contacts the photosensitive belt 11. This is completed at least before the leading end of the electrostatic latent image based on the next image data reaches the developing position.

The intermediate transfer unit 40 includes an intermediate transfer belt 41, a belt cleaning device 42, a position detecting sensor 43, and the like. The intermediate transfer belt 41 is stretched around a drive roller 44, a primary transfer roller 45, a secondary transfer opposing roller 46, a cleaning opposing roller 47, and a tension roller 48, and is driven and controlled in a direction indicated by an arrow B by a drive motor (not shown). . A plurality of position detection marks (not shown) are provided in the non-image forming area at the end of the intermediate transfer belt 41, and one of these position detection marks (the position detection mark Mark for detecting the position that first passed through the sensor 43)
Is detected by the position detection sensor 43, and image formation is started at this detection timing. Also, the belt cleaning device 4
2 is a cleaning brush 42a, a contact / separation mechanism (not shown)
During the transfer of the first color Bk image to the intermediate transfer belt 41 and the transfer of the second, third, and fourth color images to the intermediate transfer belt 41, the contact / separation mechanism is used. Cleaning brush 42 from intermediate transfer belt 41
a is kept apart. The toner cleaned from the surface of the intermediate transfer belt 41 is stored in a waste toner tank 49 provided inside the intermediate transfer unit 40.

A transfer paper is stored in a transfer paper cassette 80 of the color printer 1.
a, b, c feed in the direction of the pair of registration rollers 82,
Conveyed. On the right side of the color printer 1, O
Manual feed tray 83 for manual feed of HP paper and thick paper
Is provided.

The secondary transfer unit 50 includes a swing mechanism (not shown) having a clutch and the like for moving the secondary transfer roller 51 toward and away from the intermediate transfer belt 41. It is composed of The secondary transfer roller 51 swings about the rotation axis of the swing mechanism in synchronization with the timing at which the transfer paper reaches the transfer position. The transfer paper and the intermediate transfer belt 41 are brought into contact with each other at a constant pressure by the secondary transfer roller 51 and the secondary transfer opposing roller 46. The position accuracy of the parallelism of the secondary transfer roller 51 with the secondary transfer opposing roller 46 is maintained by a positioning member (not shown) provided in the intermediate transfer unit 40. Further, the contact pressure of the secondary transfer roller 51 with respect to the intermediate transfer belt 41 is kept constant by a positioning roller (not shown) provided on the secondary transfer roller 51. The secondary transfer roller 51 is moved to the intermediate transfer belt 4
1 and a transfer bias having a polarity opposite to that of the toner is applied to the secondary transfer roller 51 and the intermediate transfer belt 4
1 is transferred onto the transfer paper at a time.

Each of the above units can be easily detached from the apparatus. For example, in FIG. 1, when removing the intermediate transfer unit 40, the front cover (not shown) is opened, and the unit can be easily removed by sliding the unit from the back side to the front side of the paper.

In the color printer 1 having the above configuration, when the image forming cycle is started, first, the photosensitive belt 11
Is rotated clockwise by an arrow A, and the intermediate transfer belt 41 is rotated counterclockwise by an arrow B by a drive motor (not shown). A position detection mark (not shown) provided on the intermediate transfer belt 41 is detected by a position detection sensor 43, and the photosensitive belt 11 is moved in accordance with the detection timing of the position detection mark.
Bk toner image formation, C toner image formation, M toner image formation, and Y toner image formation are performed thereon, and finally Bk, C, M,
A toner image is formed on the intermediate transfer belt 41 in the order of Y. At this time, the bias applied to the primary transfer roller 45 generally increases the voltage sequentially, but differs depending on the resistance characteristics of the intermediate transfer belt 41 and the like.

The formation of the Bk toner image is performed as follows. The charging roller 13 is driven by an applied voltage of a power supply (not shown)
Charges the photoreceptor belt 11 uniformly. Then, the laser light LD for writing performs exposure based on the Bk color image signal. When this exposure is carried out, the exposed portion of the photoreceptor belt 11 which is initially uniformly charged loses the charge proportional to the amount of exposure light, and a Bk electrostatic latent image is formed. When the Bk toner on the developing sleeve 110 comes into contact with the Bk electrostatic latent image, no toner adheres to a portion of the photoreceptor belt 11 where the charge remains, and a portion having no charge, that is, an exposed portion Bk toner is adsorbed on the toner image, and a Bk toner image similar to the electrostatic latent image is formed. Then, the Bk toner image formed on the photosensitive belt 11 contacts the intermediate transfer belt 41 at the primary transfer position. At this primary transfer position, a nip is formed between the intermediate transfer belt 41 and the photosensitive belt 11 by the primary transfer roller 45 and the primary transfer opposing roller 15, and the Bk toner image is formed on the primary transfer roller 45. The Bk toner image is transferred to the intermediate transfer belt 41 by applying a bias having a polarity opposite to the above.

Some untransferred residual toner on the photoreceptor belt 11 is cleaned by the photoreceptor cleaning device 12 in preparation for reusing the photoreceptor belt 11. The collected toner is stored in a waste toner tank (not shown) via a collection pipe.

On the photosensitive belt 11 side, the process proceeds to the C image forming step after the Bk image forming step, and the position detecting sensor 4
In accordance with the detection timing of No. 3, writing by the laser light LD using the C image data is performed, and a C electrostatic latent image is formed. Then, after the trailing end of the previous Bk electrostatic latent image has passed and before the leading end of the C electrostatic latent image has arrived, the Bk developing device retreats from the developing position, and the C developing device C moves to the developing position. And the C electrostatic latent image is developed with C toner. Thereafter, the development of the C electrostatic latent image area is continued, but when the rear end of the C electrostatic latent image passes, the C developing device C is retracted from the developing position as in the case of the Bk developing device B. Then, the next M developing device M is moved to the developing position. This is also completed before the leading end of the next M electrostatic latent image reaches the developing position. The M and Y image forming processes are the same as the processes of Bk and C described above, since the operations of forming and developing the electrostatic latent image are the same as those of the processes of Bk and C described above.

On the intermediate transfer belt 41, Bk, C, M, and Y toner images sequentially formed on the photosensitive belt 11 are
A four-color toner image is formed by sequentially aligning the four colors on the same surface, and in the next secondary transfer step, the four-color toner images are collectively transferred to transfer paper.

At the time when the image forming operation is started, the transfer paper is fed from either the transfer paper cassette 80 or the manual feed tray 83, and stands by at the nip of the pair of registration rollers 82. When the leading end of the four-color superimposed toner image on the intermediate transfer belt 41 approaches the secondary transfer roller 51, the registration roller pair 82 is driven such that the leading end of the transfer paper coincides with the leading end of the toner image. The transfer paper and the toner image are aligned. Then, the transfer paper is superimposed on the toner image on the intermediate transfer belt 41 and passes through the secondary transfer position. At this time, the transfer paper is charged by the transfer bias by the secondary transfer roller 51, and most of the toner image is transferred onto the transfer paper.

The transfer paper on which the four-color superimposed toner image is collectively transferred from the intermediate transfer belt 41 is fixed to the fixing unit 60.
The toner image is melted and fixed at the nip between the fixing belt 61 and the pressure roller 62 controlled to a predetermined temperature, sent out of the apparatus main body (in the direction of arrow C), and stacked on the paper output tray 84 face down. , Get a full color copy.

When performing double-sided printing, the transfer sheet that has passed through the fixing unit 60 is guided by the discharge switching claw 85 in the direction of arrow D, and is sent to the double-sided printing sheet reversing unit 70. After the rear end of the transfer paper has passed through the paper transport switching claw 71,
The conveying roller pair 72 stops, and the transfer paper also stops. Then, the conveying roller pair 72 starts reverse rotation after a certain blank time, and the transfer paper starts switchback. At this time, the paper transport switching claw 71 is switched, and the transfer paper is guided in the direction of arrow E and sent to the registration roller pair 82. The transfer paper sent to the pair of registration rollers 82 stands by at the nip of the pair of registration rollers 82 in a state where the transfer paper is turned upside down. And
The registration roller pair 82 is driven at a predetermined timing,
After the transfer paper is sent to the secondary transfer position and the four-color superimposed toner image is collectively transferred from the intermediate transfer belt 41, the toner image is fused and fixed by the fixing unit 60 and sent out of the apparatus main body.

On the other hand, the surface of the photoreceptor belt 11 after the primary transfer is cleaned by the photoreceptor cleaning device 12 and is uniformly discharged by a discharge lamp (not shown). Also,
The surface of the intermediate transfer belt 41 after the transfer of the toner image onto the transfer paper is cleaned by pressing the cleaning brush 42a of the belt cleaning device 42 with the contact / separation mechanism. The toner cleaned from the intermediate transfer belt 41 is stored in a discharge toner tank 49.

In the color printer according to this embodiment, the photosensitive belt is used as the latent image carrier, but a drum-shaped latent image carrier can be used by keeping the hardness of the developing sleeve low. It is.

Next, the developing unit 30 will be described in more detail. Each color developing unit 31 of the developing unit 30
Since K, C, M, and Y have the same configuration, only the Bk developing device 31K will be described. FIG. 2 shows a Bk developing device 31.
FIG. 2 is a schematic configuration diagram of K. The Bk developing device 31K is a developing sleeve 1 for transferring a developer to the photoreceptor belt 11 to visualize the image.
10, a developer supply roller 120 for supplying the developer to the developing sleeve 110 while pre-charging, a developing sleeve 11
And a scraper 13 for scraping off the developer on the surface of the developer regulating roller 130 that regulates the amount of developer attached to the roller and frictionally charges the developer.
1. A developer hopper 101 that is a storage space surrounded by a case that stores the developer so as not to leak out of the developing device, and three developers that transport the developer from the developer hopper 101 to the developer supply roller 120. Transport members 141, 142, 14
3 and so on.

The developing sleeve 110 is provided with the photosensitive belt 11
In the direction of the arrow CW (clockwise) in the figure (clockwise direction) in the drawing, the linear velocity ratio is 1.
It rotates at 1 to 2.0 times speed. The three developer conveying members 141, 142, and 143 rotate in the direction of arrow CW to convey the developer to the developer supply roller 120.
The developer supply roller 120 is brought into contact with the developing sleeve 110 with a predetermined nip, and a CW
Alternatively, the developer is rotated in a CCW direction (CW in the example in the drawing), and the developer on the surface of the developer supply roller 120 is rubbed against the surface of the developing sleeve 110 in the nip to supply the developer while preliminarily frictionally charged. The developer regulating roller 130 is in contact with the developing sleeve 110 with a predetermined load by urging the bearing portion 133 toward the developing sleeve 110 with a spring 132. By allowing the developer supplied from the developer supply roller 120 to pass through the nip of the contact portion, the amount of the developer supplied is made uniform, and the developing sleeve 110
A uniform developer layer is formed in the thrust direction on the surface. Further, since the passed developer is frictionally charged by the surfaces of both the developer regulating roller 130 and the developing sleeve 110, the developer supplied to the development to the photoreceptor belt 11 has a stable charge amount. be able to.

FIGS. 3A and 3B show the developing sleeve 11.
FIG. 4 is an explanatory diagram of a state in which drive is transmitted to 0. FIG. 3 (a)
Indicates a state in which the developing sleeve 110 is separated from the photoreceptor belt 11, and the Bk developing device 31k is retracted from the developing position. In this state, the developing sleeve gear 111 and the drive gear 112 on the apparatus main body side are not engaged, and the developing sleeve 110 is freely rotatable. On the other hand, in FIG. 3B, the developer accommodating case 32K is moved by the electromagnetic solenoid 102 (see FIG. 4) as indicated by an arrow L in FIG.
, The developing sleeve 110 is moved to the photosensitive belt 11.
And the Bk developing unit 31k is in the developing position. In this state, the developing sleeve gear 111 and the drive gear 112 mesh with each other, and the drive gear 112
By rotating in the CW direction, the developing sleeve gear 111 rotates in the direction of the arrow CW.
0 also rotates in the arrow CW direction.

As described in the related art, there is a method of forming a developer layer on the developing sleeve 110 while rotating the developer regulating roller 130. However, a driving torque for driving the entire developing unit becomes large, There is a problem that vibration occurs. Therefore, the configuration may be such that the drive of the developer regulating roller 130 is separated from the drive transmission path of the developing sleeve 110, and the developer regulating roller 130 is rotationally driven when the developing sleeve 110 is not driven. This configuration includes a configuration in which each of the developing sleeve 110 and the developer regulating roller 130 has a driving system with a different drive motor, a configuration in which the driving of the developing sleeve 110 and the developer regulating roller 130 is switched by a clutch, and , Or the displacement thereof is used to drive the developer regulating roller 130. Note that the configuration having a plurality of motors requires more space than the configuration of one motor, and increases the cost.

In the color printer according to the present embodiment, the moving force of each of the developing units or the displacement thereof is used.
A configuration for driving the developer regulating roller 130 is employed. Hereinafter, this configuration and operation will be described. FIG.
FIG. 3 is a view of the vicinity of the developer regulating roller 130 as viewed from above in FIG. The developer regulating roller 130 has its rotating shaft 13
5 is rotatably held by a pair of bearing portions 133 and 134. A one-way clutch 136 and a bracket 137 via the one-way clutch 136 are provided at the lower end of the rotating shaft 135 in the drawing. A guide pin 138 is fixed to the bracket 137. Also,
The distal end portion of the guide pin 138 is
Is guided by the guide part 201 provided in the first position. Further, the developer storage case 32K has a developer storage case 3
An electromagnetic solenoid 102 for moving the entire 2K right and left in the figure is connected.

FIGS. 5A, 5B and 5C show the one-way clutch 13 as viewed from the lower side in FIG. 4 (the same direction as in FIG. 2).
FIG. 6 is a view near 6 and is an explanatory diagram of a state when an electromagnetic solenoid 102 is operated. Incidentally, for the understanding of the operation, we are given the four marks M ₁ ~M ₄ indicating the rotational position for each member. In FIG. 5A, the one-way clutch 136 includes an inner ring 136a and an outer ring 136b. A developer regulating roller shaft 135 is fixed to the inner ring 136a, and a bracket 137 is fixed to the outer ring 136b. Bracket 137 is arrow CC
When rotated in the W (counterclockwise) direction, the one-way clutch 136 idles and does not transmit the driving force, but when the bracket 137 rotates in the arrow CW (clockwise) direction, the driving force is transmitted and the developer regulating roller is rotated. 130 is rotated in the direction of arrow CW.

In the state shown in FIG.
When K (not shown) moves in the direction of the arrow L, the developer regulating roller 130 and the like also move in the direction of the arrow L, and the guide pin 138 moves with the guide groove 201 of the guide portion 201.
It moves diagonally to the upper left in the figure along a. Then, the guide pin 138 rotates the bracket 137 in the direction of the arrow CCW. The rotation of the arrow CCW direction, the one-way clutch 136 runs idle as shown in FIG. 5 (b), the mark _{M 4} of the mark _{M 3} of the developer regulating roller shaft 135 bracket 137 matches. The state shown in FIG. 5B is also a developing operation position where the developing sleeve 110 abuts on the photoreceptor belt 11 (not shown) to perform a developing operation. Since the developing sleeve 110 rotates in the direction of arrow CW during the developing operation, the developer regulating roller 130 tries to rotate in the direction of arrow CCW, but the guide pin 138 is guided by the guide groove 201a and does not move. The regulating roller 130 can regulate the developer without rotating. When the developer is regulated by the developer regulating roller 130, the developing sleeve 1
At the wedge portion between the developer roller 10 and the developer regulating roller 130, the compressed and agglomerated developer agglomerates.

When the developing operation is completed and the developer accommodating case 32K (not shown) moves in the direction of arrow R from the state shown in FIG. 5B, the developer regulating roller 130 and the like also move in the direction of arrow R at the same time. Accordingly, the guide pin 138 moves obliquely downward and rightward in the figure along the guide groove 201a. Then, the guide pin 138 moves the bracket 137 with the arrow CW.
Rotate in the direction. In the rotation in the arrow CW direction, the one-way clutch 136 transmits the driving force, and rotates the developer regulating roller 130 by a predetermined angle in the arrow CW direction. In this manner, the rotation of the developer regulating roller 130 can be performed separately from the drive transmission path of the developing sleeve 110.

Here, in FIG. 5B, when the developer accommodating case 32K (not shown) moves in the direction of arrow R and the developer regulating roller 130 rotates, at the same time, as shown in FIG. The engagement between the sleeve gear 111 and the drive gear 112 is released, the developing sleeve gear 111 becomes rotatable, and the developing sleeve 110 becomes rotatable. Then
Due to the rotation of the developer regulating roller 130, the frictional force acting between the developer regulating roller 130 and the developing sleeve 110 may cause the developing sleeve 110 to be drawn into the rotation of the developer regulating roller 130, so-called co-rotating. 6, when the developer regulating roller 130 rotates in the direction of the arrow CW, the developing sleeve 110 may rotate in the direction of the arrow CCW. When the developing sleeve 110 rotates, the mass S of the developer compressed and aggregated by the wedge portion K at the entrance of the contact portion between the developer regulating roller 130 and the developing sleeve 110 forms the developing sleeve 110 and the developer regulating roller 1.
30 are divided into two sides, each of which is
The phenomenon of moving at 0S and 130S occurs. When this phenomenon occurs, as described above, the developing sleeve 110
When the rotation of the developer starts, the mass 110S of the developer attached to the developing sleeve 110 is removed by the developer regulating roller 130.
And the developer layer is temporarily disturbed. Particularly, the above-mentioned mass of the developer which has been compressed and agglomerated 11
When the OS passes through the nip, the developer is scattered.

As a result of intensive studies by the present inventor to solve this problem, it has been found that when the developer regulating roller 130 rotates, the developing sleeve 110 should be stopped to prevent entrainment as much as possible. By doing so, the developer mass S compressed and agglomerated by the wedge K is easily moved away from the developer sleeve 110 by receiving the moving force from the developer regulating roller 130. Further, the developing sleeve 11
A small vibration is generated due to the rubbing between 0 and the developer regulating roller 130, and the above-mentioned mass S is easily collapsed. From such an effect, the mass S of the developer does not remain on the developing sleeve 110, or even if it remains, the mass S becomes small, the cohesive force is weakened, and the developer is easily broken. Thereby, the temporary disturbance of the developer layer and the scattering of the developer can be prevented.

As a condition for stopping the developing sleeve 110 when the developer regulating roller 130 rotates to prevent the developing sleeve 110 from rotating, the following condition 1 is satisfied in the Bk developing unit 31K. The configuration may be simplified. There is also a method of applying a braking force to the developing sleeve 110 from the outside,
The mechanism becomes complicated. In the equation (1), T is the starting torque required for the developing sleeve 110 to start rotating from a stationary state, P is the pressure applied between the developer regulating roller 130 and the developing sleeve 110, and μmax is the developer regulating roller 130. The maximum coefficient of static friction between the developing sleeve 110 and r is the distance (radius) from the rotation center of the developing sleeve 110 to the surface.

[0055]

[Equation 1] T> μmax · P · r

By satisfying the above condition (1), FIG.
In (b), the developer storage case 32K (not shown)
With the movement in the direction of arrow R, the developer regulating roller 130
Even if the developing sleeve 110 rotates in the direction of the arrow CW,
Without turning, as shown in FIG.
Mark M of 0₁And mark M of developer regulating roller 130 ₂
Are shifted from each other.

[Embodiment 1] Next, a concrete embodiment for satisfying the above condition (1) will be described. In this embodiment, in FIG. 2, the drive transmission means of the developer supply roller 120 is connected to the drive transmission means of the developing sleeve 110. FIG. 7 is an explanatory diagram of a configuration in which the drive transmission unit of the developer supply roller 120 is connected to the drive transmission unit of the developing sleeve 110. In the developer storage case 32K,
The developing sleeve gear 111 and the idle gear 121 mesh with each other, and the idle gear 121 and the developer supply roller gear 122 mesh with each other. As a result, the developing sleeve gear 111 and the developer supply roller gear 122 rotate in the same direction. For example, when the developing sleeve gear 111 rotates in the direction of the arrow CCW, the idle gear 121 rotates in the direction of the arrow CW, and the developer supply roller gear 122 rotates in the direction of the arrow CCW. Therefore, the developing sleeve 110 and the developer supply roller 120 rotate in the same direction, and their contact portions rotate in directions opposite to each other. In the contact portion, the developing sleeve 110 and the developer supply roller 120 rotate and move in opposite directions with a peripheral speed difference, so that the developer supply roller 120 applies a brake to the rotation of the developing sleeve 110.

When the developer regulating roller 130 rotates in the direction of the arrow CW in the figure while the Bk developing device 31k is retracted from the developing position, a frictional force acts on the developing sleeve 110 in the direction of the arrow CCW. . Here, in order to prevent the developing sleeve 110 from rotating with the rotation of the developer regulating roller 130, the following condition 2 may be satisfied. Here, Fsup is a frictional force acting between the developer supply roller 120 and the developing sleeve 110, and r is a distance (radius) from the rotation center of the developing sleeve 110 to the surface.

[0059]

[Equation 2] Fsup · r> μmax · P · r

As described above, the drive transmitting means for transmitting the driving force of the developing sleeve 110 and the developer supply roller 12
Since the drive transmitting means for transmitting the driving force of the developer supply roller 120 is not connected, the developing sleeve 110 is moved from the stationary state as compared with the case where the drive transmitting means for transmitting the driving force of the developer supply roller 120 is not connected. The starting torque T of Expression 1 required to start the rotation is obtained by also weighting the starting torque required to start the rotation of the developer supply roller 120 from the stationary state. Therefore, the starting torque T becomes larger than when there is no such weight, and accordingly, μmax, P, and r that satisfy the above relationship can be made larger. Therefore, for example, by increasing μmax or P, it is possible to more efficiently regulate the developer.
When the developer is a one-component developer, the charge amount can be further increased. Also, by increasing r, the area of the developing sleeve 110 increases, and a predetermined amount of developer can be transported even when the number of rotations is reduced.
The durability of the developing sleeve 110 can be improved.

In the above configuration, since the developing sleeve 110 and the developer supply roller 120 rotate in opposite directions at the contact portion with a peripheral speed difference, the rotation of the developing sleeve 110 causes the developer supply roller 120 to brake. Will be applied. To apply the brake, the developer supply roller 12
It is necessary that the surface of No. 0 has a predetermined roughness and a predetermined frictional force acts on the surface of the developing sleeve 110. Therefore, the developer supply roller 120 has an Asker C hardness of 5
The surface has a cell diameter of 0.05 in the range of [degree] to 30 [degree].
It is desirable for the operation to be made of a foam material of [mm] to 0.5 [mm]. As a material of the developer supply roller 120, polyurethane, polycarbonate, silicon, EP
By using DM or the like, the braking action can be satisfied. Here, if the hardness of the developer supply roller 120 is lower than 5 [degrees], the contact pressure against the developing sleeve 110 decreases, and the frictional force at the contact portion decreases, resulting in an insufficient braking force. On the other hand, if the hardness is higher than 30 [degrees], the contact pressure becomes excessive to secure a predetermined amount of nip width between the developer supply roller 120 and the developing sleeve 110, and the driving torque during the developing operation increases. . If the cell diameter of the foamed material is smaller than 0.05 [mm], the developer supply and supply power is insufficient, and the condition as a supply member cannot be satisfied. On the other hand, when the cell diameter is larger than 0.5 [mm], the contact area with the developing sleeve 110 is small, so that the frictional force at the contact portion is insufficient. Further, toner clogging is liable to occur, and the conveyance supply power is reduced with time. Table 1 shows experimental results when the cell diameter was changed in the developer supply roller 120 whose surface was made of urethane foam.

[0062]

[Table 1]

Second Embodiment In the first embodiment, the drive transmission means of the developer supply roller 120 is connected to the drive transmission means of the developing sleeve 110 in order to satisfy the above condition (1). The three developer conveying members 14
1, 142, 143 to the developing sleeve 11
It is also possible to adopt a configuration in which it is connected to zero drive transmission means.

FIG. 8 shows three developer conveying members 141, 1
It is explanatory drawing of the drive transmission means which rotates 42,143. The first idle gear 14 is attached to the developing sleeve gear 111.
4 mesh with each other, and the first paddle gear 145 meshes with the first idle gear 144. Similarly, the second idle gear 146 meshes with the first paddle gear 145,
The second paddle gear 147 meshes with the second idle gear 146. Further, the third idle gear 148 meshes with the second paddle gear 147, and the third idle gear 1
The third paddle gear 149 meshes with 48. Thereby, during the developing operation, the developing sleeve gear 111
By rotating in the W direction, the three developer transport members 14
1, 142, 143 can be rotationally driven in the same direction of rotation CW. The illustrated example shows a state in which the Bk developing device 31K is retracted from the developing position, and the developing sleeve gear 111 is not meshed with the drive gear 112 (see FIG. 3A). In the Bk developing device 31 </ b> K having the above configuration, in order to prevent the developing sleeve 110 from rotating with the rotation of the developer regulating roller 130, the following condition (3) may be satisfied. However, Tpud is a starting torque required to start rotation of the developing sleeve 110 from a stationary state when the drive transmitting means of the three developer conveying members 141, 142, and 143 are connected to the drive transmitting means of the developing sleeve 110. It is.

[0065]

[Equation 3] Tpud> μmax · P · r

The three developer conveying members 141, 142, 1
A torque 43 is required to transport the developer in the developer accommodating case 32K, and the torque applies a brake to the developing sleeve 110. Therefore, the rotation of the developer regulating roller 130 causes the developing sleeve 110 to rotate.
Can be prevented from rotating around. In the illustrated example, the angles of the blades are shifted from each other so that the rotational torque of the three developer conveying members 141, 142, and 143 does not vary depending on the rotation angles of the blades. Further, by increasing the number of blades of each of the developer conveying members 141, 142, and 143, torque fluctuation can be further reduced. As described above, the drive transmitting means for transmitting the driving force of the developing sleeve 110, and the three developer conveying members 141, 14
2 and 143 are connected to a drive transmission means for transmitting the driving force of each developer transport member 141, 142, 14.
The starting torque Tpud required to start the rotation of the developing sleeve 110 from the stationary state is smaller than that in the case where the driving force transmitting means for transmitting the driving force of No. 3 is not connected to each of the developer conveying members 141, 142, 143. The starting torque required to start the rotation from the stationary state is also weighted. Therefore, the starting torque Tpud becomes larger than when there is no such weight, and accordingly, μmax, P, and r that satisfy the above relationship can be made larger. Therefore, for the same reason as described above for the first embodiment,
The regulation of the developer can be performed more efficiently. When the developer is a one-component developer, the charge amount can be further increased. Further, the developing sleeve 110
Can be improved in durability.

[Embodiment 3] Further, the drive transmitting means for the developing sleeve 110 and the drive transmitting means for rotating a plurality of members in the Bk developing unit 31K except the developer regulating roller 130 are connected, and May be configured to satisfy the following. However, Trot has three developer conveying members 141,
142, 143 and the developer supply roller 1
This is the starting torque required to start the rotation of the developing sleeve 110 from a stationary state when the drive transmitting unit 20 and the drive transmitting unit 20 are connected to each other. For example, in FIG. 8, the developer supply roller gear 122 shown in FIG.

[0068]

[Equation 4] Trot> μmax · P · r

As described above, the drive transmitting means for transmitting the driving force of the developing sleeve 110 and the developer supply roller 12
Since the drive transmitting means for transmitting the driving force of 0 and the driving transmitting means for transmitting the driving forces of the three developer conveying members 141, 142, 143 are connected, these drive transmitting means are not connected. Developing sleeve 11
0 is the starting torque Trot required to start rotation from the stationary state, and the starting torque Trot required to start rotation of the developer supply roller 120 and the three developer conveying members 141, 142, and 143 from the stationary state. It will be weighted. Therefore, the starting torque Trot becomes larger than when there is no such weight, and accordingly, μmax, P, and r satisfying the relationship of the above equation 4 can be made larger.
Therefore, for the same reason as described above in the first embodiment, the regulation of the developer can be performed more efficiently. When the developer is a one-component developer, the charge amount can be further increased. Further, the durability of the developing sleeve 110 can be improved.

Further, in addition to the configuration satisfying the condition of the above expression 4, a stationary member which directly contacts the developing sleeve 110,
For example, an end seal for preventing leakage and scattering of the developer, a cleaning member for mechanically and electrically removing toner and the like on the surface of the developing sleeve 110, and the like may be provided so as to satisfy the condition of Expression 5. Here, Tf is the torque applied to the developing sleeve 110 by the frictional force with the stationary member.

[0071]

## EQU5 ## Trot + Tf> μmax · P · r

As described above, the torque Tf weighted by the frictional force of the stationary member allows μma that satisfies the relationship of Equation 5 to be obtained.
x, P, and r can be increased.

Fourth Embodiment In the first, second, and third embodiments, the configuration in which the rotation start torque T of the developing sleeve 110 is increased to prevent the developing sleeve 110 from rotating together has been described. However, as a result of further study by the present inventor, it is also effective to reduce the frictional force between the developing sleeve 110 and the developer regulating roller 130 as far as the condition is satisfied, in order to prevent the developing sleeve 110 from rotating together. It turns out. Therefore, at least one surface of the developing sleeve 110 or the developer regulating roller 130 is made of a fluororesin, a polyamide resin, or a urethane resin. Thereby, the developing sleeve 11
In addition to reducing the frictional force between 0 and the developer regulating roller 130 to prevent entrainment, it was possible to secure the transport amount and charge amount of the developer layer required for development.

Further, at least one surface of the developing sleeve 110 or the developer regulating roller 130 is made of melamine resin, guanamine resin, stainless steel, electroless Ni.
The developing sleeve 1 is made of plating, aluminum, or aluminum anodized to reduce the frictional force.
10 can be prevented from rotating. Further, it is preferable that the surface portions of the developing sleeve 110 and the developer regulating roller 130 are formed by combining the above-mentioned fluororesin or the like and the above-mentioned melamine resin or the like in terms of developer characteristics (transport amount / charge amount). It was confirmed. For example, the developing sleeve 110
Is made of a fluororesin, and the developer regulating roller 13
The surface of No. 0 is made of melamine resin. On the other hand, as an example in which the frictional force between the developing sleeve 110 and the developer regulating roller 130 is large and it is difficult to prevent the developing sleeve 110 from rotating together, the surface of the developer regulating roller 130 may be made of urethane rubber, EPDM, NBR, or the like. Sometimes a rubber agent. With these rubber agents, the grip force is increased, and it is difficult to completely prevent the developing sleeve 110 from rotating together.

As described above, when at least one surface of the developing sleeve 110 or the developer regulating roller 130 is made of the fluororesin or the melamine resin, the surface is made of urethane rubber or the like. The developing sleeve 110 and the developer regulating roller 1
30 can be reduced.
Accordingly, P and r satisfying the relationship of Equation 1 can be made larger. Therefore, for the same reason as described above in the first embodiment, if the developer is a one-component developer, the charge amount can be further increased. Further, the durability of the developing sleeve 110 can be improved.

[Embodiment 5] Further, the frictional force between the developing sleeve 110 and the developer regulating roller 130 can be reduced by increasing the fluidity of the developer. When a particle (external additive) having an average particle diameter of 0.5 [μm] or less is externally added to the periphery of the colored particles as a component of the one-component developer in order to increase the fluidity of the developer, This has the effect of reducing the frictional force between the developer carrier and the developer regulating member. In FIG. 2, the developer on the surface of the developer regulating roller 130 is scraped off by the scraping member 13.
However, the external additive easily passes through the scraping member 131, and the external additive goes around the roller surface by the rotation of the developer regulating roller 130, enters the contact nip with the developing sleeve 110, and is lubricated. Act as Thereby, it is considered that the frictional force between the developing sleeve 110 and the developer regulating roller 130 is reduced.
Table 2 is a table showing the results of experiments conducted on the fluidity of the developer by changing the particle size of the external additive. As an external additive,
Experiments were performed with silica particles and titanium oxide particles. Also,
The toner particle diameter of the developer is about 6 [μm].

[0077]

[Table 2]

As can be seen from Table 2 above, when the particle size of the external additive is 0.5 [μm] or less, the fluidity of the developer is good, and the gap between the developing sleeve 110 and the developer regulating roller 130 is good. The frictional force of the developing sleeve 110 is reduced, and the rotation of the developing sleeve 110 can be prevented. On the other hand, the particle size of the external additive is 0.5 [μ
m], the flowability of the developer may be impaired, and the developing sleeve 110 may rotate. As described above, as a component of the developer, the average particle diameter is 0.1.
Since particles of 5 μm or less are externally added to the periphery of the colored particles, the fluidity of the developer is improved, and the developing sleeve 110
Since the frictional force between the roller and the developer regulating roller 130 is reduced, r that satisfies the relationship of the above equation 1 can be increased accordingly. Therefore, the durability of the developing sleeve 110 can be improved for the same reason as described above in the first embodiment.

[0079]

According to the first to eighth aspects of the present invention, the developer carrier is not rotated by the rotation of the developer regulating member, and the aggregate of the developer agglomerated by compression is removed by the developer carrier. Does not remain on the surface. Thus, when the developer carrier rotates in the next developing operation, there is an excellent effect that scattering of the developer from the nip due to the above-mentioned mass of the developer can be prevented.

In particular, according to the second, fourth and fifth aspects of the present invention, μmax, P and r satisfying the above relationship can be made larger. By increasing the value of μmax or P, the developer can be regulated more efficiently. When the developer is a one-component developer, the charge amount can be further increased. In addition, if the developer carrier is a roller, increasing the value of r increases the area of the developer carrier, so that a predetermined amount of developer can be transported even when the number of rotations is reduced. In addition, the durability of the developer carrier can be improved.

In particular, according to the third aspect of the present invention, the hardness (Asker C) of the supply member is 5 degrees or more and 30 degrees or less, and the cell diameter of the foam material is 0.05. Since it is not less than [mm] and not more than 0.5 [mm], there is no shortage of the braking effect of the supply member on the developer carrier, and it is possible to maintain the developer supply force. Has an excellent effect.

In particular, according to the invention of claim 6, P and r satisfying the above relationship can be made larger. Therefore, for the same reason as described in claim 2, if the developer is a one-component developer, the charge amount can be further increased. Further, there is an excellent effect that the durability of the developer carrying member can be improved.

In particular, according to the invention of claim 7, r satisfying the above relationship can be increased. Therefore, there is an excellent effect that the durability of the developer carrying member can be improved for the same reason as described in the second aspect.

In particular, according to the invention of claim 8, during the developing operation of the developing device, it is possible to prevent the developer from scattering from the nip between the developer carrier and the developer regulating member. As a result, there is an excellent effect that the operation of the apparatus main body can be prevented from being adversely affected without soiling the transfer material and the inside of the apparatus main body due to the scattering of the developer.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part of a color printer according to an embodiment.

FIG. 2 is a schematic configuration diagram of a Bk developing device.

FIGS. 3A and 3B are diagrams illustrating a state in which drive is transmitted to a developing sleeve 110. FIGS.

FIG. 4 is a view of the vicinity of a developer regulating roller viewed from above in FIG.

5 (a), 5 (b) and 5 (c) show the lower side of FIG. 4 (FIG. 2).
FIG. 4 is a view of the vicinity of the one-way clutch 136 as viewed from the same direction as FIG. 4, and is an explanatory diagram of a state when the electromagnetic solenoid 102 is operated.

FIG. 6 is an explanatory diagram of a state in which a cluster of developer that has been compressed and aggregated adheres to the surface of a developing sleeve.

FIG. 7 is an explanatory diagram of a configuration in which a drive transmission unit of a developer supply roller 120 is connected to a drive transmission unit of a developing sleeve 110.

FIG. 8 shows three developer conveying members 141, 142, and 143.
FIG. 4 is an explanatory diagram of a drive transmission unit that rotationally drives the motor.

FIG. 9 is a schematic configuration diagram illustrating an example of a conventional developing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Color printer 10 Photoreceptor unit 11 Photoreceptor belt 30 Developing unit 31K Bk developing device 32K Developer accommodating case 102 Electromagnetic solenoid 110 Developing sleeve 111 Developing sleeve gear 112 Drive gear 120 Developer supply roller 130 Developer regulating roller 136 One-way clutch 138 Guide pins 141, 142, 143 Developer transport member 201 Guide portion 201a on main assembly side Guide groove

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G03G 15/08 505 G03G 15/08 505A 507 F16C 13/00 E F16C 13/00 A G03G 9/08 371 G03G 9/08 371 15/08 507E 507L F-term (reference) 2H005 AA08 EA05 2H077 AB14 AC04 AD02 AD04 AD06 AD14 AD17 AE01 BA01 BA02 BA03 CA11 EA11 EA15 EA16 FA11 FA13 FA14 3J103 AA02 FA01 FA04 FA19 FA30 GA02 GA52 GA60 GA41 GA33 HA43 HA46 HA48

Claims (8)

[Claims] An image forming apparatus comprising: a developer carrying member which adheres to a developer while rotating in proximity to or in contact with an image carrier to form a visible image; A developing device comprising: a supply unit that supplies the developer; and a developer regulating member that contacts the developer carrier and regulates the developer layer on the developer carrier to form a certain amount of the developer layer. The developer regulating member is formed in a roller shape, and has a rotation driving unit that rotates the developer regulating member by a predetermined angle when the developing carrier is not driven, and starts the rotation of the developer carrier from a stationary state. The starting torque required for the above is T, and the maximum static friction coefficient between the developer regulating member and the developer carrier is μma.
x, where P is the pressure applied between the developer regulating member and the developer carrier, and r is the distance from the center of rotation of the developer carrier to the surface, the relationship of T> μmax · P · r A developing device characterized by satisfying the following. 2. The developing device according to claim 1, wherein said supply means is constituted by a supply member which supplies said developer in contact with said developer carrier, and transmits a driving force of said developer carrier. A developing device, wherein a drive transmitting means and a drive transmitting means for transmitting a driving force of the supply member are connected. 3. The developing device according to claim 2, wherein said supply member has a foam material on its surface, and has a hardness (Asker C) of 5 degrees or more and 30 degrees or less. A developing device, wherein the cell diameter of the foam material is 0.05 mm or more and 0.5 mm or less. 4. The developing device according to claim 1, further comprising: a developer accommodating section for accommodating said developer; and at least one developer conveying member for conveying the developer from said developer accommodating section to said supply means. And a drive transmitting means for transmitting the driving force of the developer carrying member and a drive transmitting means for transmitting the driving force of the developer conveying member. 5. A developing device according to claim 1, wherein said supply means is constituted by using a supply member for supplying said developer in contact with said developer carrier, and a developer accommodating portion for accommodating said developer. A drive transmitting means for transmitting a driving force of the developer carrying member, the drive transmitting means having at least one developer conveying member for conveying the developer from the developer accommodating portion to the supply member; And a drive transmitting means for transmitting the driving force of the developer conveying member. 6. A developing device according to claim 1, wherein at least one surface of said developer carrier or said developer regulating member is made of fluorine resin, polyamide resin, urethane resin, melamine resin, guanamine resin, stainless steel, A developing device comprising electroless Ni plating, aluminum or aluminum alumite. 7. The developing device according to claim 1, wherein particles having an average particle diameter of 0.5 [μm] or less are externally added to the periphery of the colored particles as a component of the developer. Developing device. 8. An image forming apparatus comprising: a latent image carrier for carrying a latent image of an image on a surface; a developing device for developing the latent image with a developer; and a transfer material on which the developed image is transferred. 9. An image forming apparatus according to claim 1, wherein the developing device according to claim 1 is used as the developing device.