JP2001255729A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device which provides an excellent image without having surface staining at the start of image forming by preventing the toner concentration of developer from partially increasing on a developer carrier when attaching a developing device to a device main body. SOLUTION: In the image forming device in which the developer 3 is fed to the inside of a developer storing part A at an attaching time, it possesses a controlling means to delay the rotation start of an agitator 9 for the rotation start of a developing sleeve 4 after attachment. For instance, the rotary shaft 16a of an agitator rotation gear and the rotary shaft 9a of the agitator are screwed by a screw, and at least before the attachment, the rotary shaft 16a of the agitator rotation gear and the rotary shaft 9a of the agitator are screwed in a relatively movable state and when relative movement is stopped and screwing is completed after the attachment, the rotary shaft 16a of the agitator rotation gear and the rotary shaft 9a of the agitator are integrally rotated. Thus, toner replenishment is started after the developer 3 at the inside of the developer storing part A is uniformly carried on the developing sleeve 4 by the rotation of the developing sleeve 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile, a printer, and the like, and more particularly, to an image forming apparatus having a developing device capable of self-controlling the toner density with a small amount of developer. It is about.

[0002]

2. Description of the Related Art Hitherto, there has been known an image forming apparatus provided with a developing device capable of self-controlling the toner concentration with a small amount of developer. A system that self-controls the toner concentration with a small amount of developer means that the developer on the developer carrier and the toner replenished from the toner replenishing port of the toner container are changed due to the change in the bulk of the developer caused by the change in the toner concentration. This system changes the state of contact with the developer and changes the state of taking in toner into the developer, thereby self-controlling the toner concentration (see Japanese Patent Application Laid-Open Nos. 9-22178 and 9-197833). The developing device of this system has less magnetic carrier than the usual two-component developing system, greatly reduces the torque of the device, and takes in the toner by the movement of the magnetic carrier. Means for detecting and adjusting the mixing ratio) can be simplified. Further, it is possible to omit a stirring member such as a paddle screw. Therefore, it is advantageous for miniaturization and cost reduction.

Incidentally, in an unused developing device before being mounted on the apparatus main body, the initial developer whose toner concentration has been adjusted in advance is sealed in the initial developer accommodating portion provided near the developer accommodating portion. Is housed. The toner concentration of the initial developer can be adjusted by changing the amount of the magnetic carrier in the developer. Then, when the unused developing device is mounted on the apparatus main body, the seal member separating the developer accommodating portion and the initial developer accommodating portion is peeled off. As a result, the initial developer is supplied from the initial developer storage section into the developer storage section, and the initial developer is uniformly carried on the developer carrying member.

Further, in an unused developing device, toner is stored in a sealed state in a toner storage portion having a toner supply port for supplying toner to the developer on the developer carrier. This is to prevent the toner from aggregating in the toner supply port and scattering of the toner from the toner storage unit. Then, when the unused developing device is mounted on the device main body,
The seal member that separates the toner supply port from the toner container is peeled off. As a result, the toner is supplied to the toner supply port.

When an unused developing device is mounted on the apparatus main body, a control section of the image forming apparatus detects a mounting detection signal from a sensor 108 of the developing device mounting section. In response to this detection signal, generally, the developer carrier and the toner supply member provided in the toner accommodating section start rotating simultaneously via a drive gear, and the initial developer in the developer accommodating section is carried on the surface of the developer carrier. The toner is supplied to the developer on the developer carrier.

[0006]

However, as described above, when the developer carrying member and the toner supply member start rotating simultaneously after the developing device is mounted on the main assembly of the device, the developer from the developer accommodating portion is discharged. In a state where the toner is not uniformly carried on the surface of the developer carrying member, there is a possibility that the toner is supplied to the surface of the developer carrying member from the toner supply port. If the toner is replenished while the developer is not uniformly carried on the developer carrying member, the toner density will increase in a portion where the developer is not sufficiently carried. As a result, there occurs a problem that an abnormal image such as background contamination occurs at the start of image formation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to reduce the toner concentration of the developer on the developer carrier when the developing device is mounted on the apparatus main body. It is an object of the present invention to provide an image forming apparatus capable of preventing ascending and obtaining a good image without background contamination at the start of image formation.

[0008]

In order to achieve the above-mentioned object, a first aspect of the present invention has a first magnetic field generating means inside and carries a two-component developer containing a toner and a magnetic carrier. Developer carrying member, a developer regulating member that regulates the amount of developer carried and carried by the developer carrying member, and a developer accommodating the developer scraped off by the developer regulating member. A developer accommodating portion and a developer accommodating portion which is adjacent to the developer carrying member from the upstream side of the developer carrying direction of the developer carrying member so that the contained toner comes into contact with the developer on the developer carrying member and is taken in. A developing device having a toner storage section having a toner supply port and a toner supply member for supplying toner in the toner storage section to the toner supply port; when the developing apparatus in an unused state is mounted on the apparatus main body, Image in which developer is charged into the developer storage section In forming apparatus, it is characterized in that it has a control means for delaying the start of rotation of the toner supply member with respect to the rotation start of the developer carrying member after mounting.

In this image forming apparatus, after the developing device is mounted on the apparatus main body, first, only the developer carrier starts to rotate, and the developer from the developer accommodating portion is rotated by the rotation of the developer carrier. It is homogenized on the carrier. Thereafter, the toner supply member starts to rotate, and the toner is supplied from the toner supply port to the developer on the developer carrying member by the rotation of the toner supply member. Therefore, the toner is not replenished to the portion of the developer carrying member where the developer is insufficiently supported, and it is possible to prevent a partial increase in toner concentration in the developer on the developer carrying member. Become.

According to a second aspect of the present invention, in the image forming apparatus of the first aspect, the control means includes a clutch for stopping rotation of the toner supply member for a predetermined time from the start of rotation of the developer carrier. It is provided on a member.

In this image forming apparatus, the toner supply member does not rotate due to the clutch provided on the toner supply member even if the developer carrier starts rotating after the developing device is mounted on the apparatus main body. After the developer from the developer accommodating section is uniformly carried on the developer carrying member by the rotation of the developer carrying member, the toner supply member starts to rotate by the clutch, and the toner flows from the toner supply port onto the developer carrying member. Of developer. Therefore, the toner is not replenished to the portion of the developer carrying member where the developer is insufficiently supported, and it is possible to prevent a partial increase in the toner density in the developer on the developer carrying member. Becomes

According to a third aspect of the present invention, in the image forming apparatus according to the first aspect, the control means includes a rotary gear that engages with a drive gear that rotates in conjunction with a drive source.
The rotating shaft of the rotating gear and the rotating shaft of the toner supply member are screwed together with a screw. At least before attachment, the rotating shaft of the rotating gear and the rotating shaft of the toner supply member are screwed in a relatively movable state. When the relative movement stops after the mounting and the screwing is completed, the rotation shaft of the rotary gear and the rotation shaft of the toner supply member rotate integrally.

In this image forming apparatus, after the developing device is mounted on the main assembly of the apparatus, even if the developer carrier starts to rotate, the rotation shaft of the rotation gear and the rotation shaft of the toner supply member can be relatively moved. Therefore, the toner supply member does not rotate. When the relative movement stops due to the rotation of the rotating gear and the screwing is completed, the toner supply member starts to rotate. Therefore, after the developer from the developer accommodating portion is made uniform on the developer carrier by the rotation of the developer carrier, the toner is supplied from the toner supply port to the developer on the developer carrier by the rotation of the toner supply member. Supplied to Therefore, the toner is not replenished to the portion of the developer carrying member where the developer is insufficiently supported, and it is possible to prevent a partial increase in toner concentration in the developer on the developer carrying member. Become. Also,
In this image forming apparatus, there is no need to add a complicated component such as a clutch as a control unit.

According to a fourth aspect of the present invention, in the image forming apparatus of the third aspect, after the developer in the developer accommodating portion is uniformly carried on the developer carrying member, the rotating shaft of the rotating gear and the developer are rotated. The rotation shaft of the toner supply member starts to rotate integrally.

In this image forming apparatus, after the developing device is mounted on the apparatus main body, the developer in the developer accommodating portion is uniformly carried on the developer carrying member, and then the rotating shaft of the rotating gear and the toner supply member are rotated. Since the rotation shaft starts to rotate integrally with the toner, the toner is not replenished to the portion of the developer carrying member where the developer is insufficiently supported.
Partial rise in toner density can be prevented.

According to a fifth aspect of the present invention, in the image forming apparatus of the first aspect, the control means rotates in conjunction with a drive source and engages with the rotary gear of the toner supply member only within a predetermined rotation angle range. And a driving gear that is not engaged with the rotating gear of the toner supply member at least before mounting.

In this image forming apparatus, even if the developer carrier starts to rotate after the developing device is mounted on the main assembly of the apparatus, the driving gear and the rotating gear are in a disengaged state at the time of mounting. The member does not rotate. When the drive gear starts to rotate and the drive gear and the rotation gear of the toner supply member are engaged, the toner supply member starts to rotate. Therefore, after the developer from the developer accommodating portion is made uniform on the developer carrier by the rotation of the developer carrier, the toner is supplied from the toner supply port to the developer on the developer carrier by the rotation of the toner supply member. Supplied to Therefore, the toner is not replenished to the portion of the developer carrying member where the developer is insufficiently supported, and it is possible to prevent a partial increase in the toner density in the developer on the developer carrying member. Becomes Further, in this image forming apparatus, there is no need to add a complicated component such as a clutch as a control unit.

According to a sixth aspect of the present invention, in the image forming apparatus of the first aspect, the developer accommodating portion is provided on the upstream side of the first developer regulating member in the developer conveying direction. A developer regulating member, wherein the second developer regulating member increases the developer concentration when the toner concentration of the developer on the developer carrier increases and the layer thickness of the developer increases. In order to restrict the passage of the minute, the distance from the developer carrier is set.

In this image forming apparatus, when the toner concentration of the developer increases, the second developer regulating member regulates the passage of the increased bulk developer on the developer carrier, and the regulated developer As a result, the toner supply port is closed, and the amount of toner taken into the developer on the developer carrier decreases. Conversely, when the toner concentration of the developer decreases, the bulk of the developer decreases, so that the toner is taken into the developer on the developer carrying member without closing the toner supply port. Therefore, the toner concentration of the developer can always be kept in a substantially constant range.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a developing device of an electrophotographic copying machine (hereinafter, referred to as a printer) as an image forming apparatus will be described. FIG. 1 is a schematic configuration diagram of the developing device. FIG. 2 is a control block diagram including a control unit of the developing device. First, the configuration and operation of the entire printer will be described. In FIG. 1, a photosensitive drum 1 serving as an image carrier is uniformly charged by a charging unit (not shown) while being driven to rotate in a direction indicated by an arrow a in FIG. And an electrostatic latent image is formed on the surface. The electrostatic latent image formed on the photosensitive drum 1 is developed by a developing device described later, and a toner image is formed on the photosensitive drum 1. The toner image formed on the photosensitive drum 1 is transferred and fixed on a sheet by a transfer device and a fixing device (not shown). Note that the residual toner on the photosensitive drum 1 that has not been transferred is removed from the photosensitive drum 1 by a cleaning device (not shown).

In FIG. 2, the control unit 100 includes a CPU 1
01, a ROM 102, and a RAM 103. The control unit 100 includes an operation unit 104 and a latent image forming unit 1.
05, a developing unit driving unit 106, a photoconductor driving unit 107, a sensor 108, and the like are connected. In the control unit 100, based on an input signal from the operation unit 104, the latent image forming unit 105, the developing unit driving unit 106, and the photoconductor driving unit 10
7 and so on. When a latent image is formed on the photosensitive drum 1 by the latent image forming unit 105 and the photosensitive drum 1 is driven to rotate by the photosensitive unit driving unit 107, the developing sleeve 4 and the agitator are driven by the developing unit driving unit 106 as described later. 9 is driven to rotate, and the latent image on the photosensitive drum 1 is developed. When an unused developing device is mounted on the printer main body, a mounting detection signal is sent to the control unit 100 from a sensor 108 provided in the mounting unit. The control unit 100 that has detected the attachment detection signal drives the developing unit driving unit 106 to carry the developer from the developer accommodating unit on the developing roller, as described later.

Next, the structure and operation of the developing device will be described. The developing device is disposed on the side of the photosensitive drum 1, and inside the developing casing 2 having an opening formed toward the photosensitive drum 1, the toner and the magnetic material are partially exposed from the opening. A developing sleeve 4 made of a non-magnetic material as a developer carrying member carrying a developer 3 made of a carrier on the surface; a magnet roller 5 as a magnetic field generating means fixedly arranged inside the developing sleeve 4;
A doctor 6 as a first developer regulating member for regulating the amount of developer carried and conveyed thereon, a developer accommodating case 7, a toner hopper 8 as a toner accommodating section, and the like are provided.

The developer accommodating case 7 is a developer accommodating portion for accommodating the developer which is not supplied to the developing position opposite to the photosensitive drum 1 between the developing sleeve 4 and the developer 6 and is prevented from advancing by the doctor 6. A is formed. And the developer sleeve 4
A magnetic pole 5a for supporting the developer 3 in the developer accommodating portion A on the developing sleeve 4 is arranged at a position facing the developer accommodating portion A in the magnet roller 5 fixed and disposed inside the magnetic roller 5a. are doing. Further, the toner hopper 8 has a toner supply port 8a adjacent to the upstream side of the developer accommodating section A in the developer transport direction and facing the surface of the developing sleeve 4, and a space adjacent to the toner supply port 8a has ,
The new toner 11 in the toner hopper 8 is
An agitator 9 is disposed as a toner supply member that sends out the toner while stirring toward a. This agitator 9
Is set so that the position of the rotating shaft and the length of the wing are adjusted, and the outermost trajectory of the agitator 9 does not swing to the developer 3 as shown by the broken line in the figure.

In the developing device having the above structure, the developer 3 carried on the developing sleeve 4 is conveyed on the developing sleeve 4 toward the doctor 6 with the rotation of the developing sleeve 4 rotating in the direction of arrow b in the drawing. , Is regulated by the doctor 6 to be thinned. The thinned developer 3 is conveyed to a development area facing the photosensitive drum 1 rotating in the direction of arrow a in the figure. Then, in the developing area, toner is supplied to the electrostatic latent image formed on the photosensitive drum 1 in a contact or non-contact manner, and the electrostatic latent image is visualized. Thereafter, the developer 3 is moved along with the rotation of the developing sleeve 4.
The upper portion is conveyed to the toner replenishing port 8a side, takes in new toner 11 sent out by the agitator 9 in the toner hopper 8 and supplied from the toner replenishing port 8a, and returns to the developer accommodating portion A. Then, the internal pressure of the developer 3 containing the new toner 11 at the regulating portion by the doctor 6 increases, and the toner of the developer 3 is frictionally charged. As described above, the toner in the developer 3 on the developing sleeve 4 can be charged by the internal pressure of the developer 3 in the developer accommodating section A. Therefore, a paddle or a screw for charging or stirring the developer 3 is used. The complicated stirring / conveying mechanism used becomes unnecessary.

On the other hand, a part of the developer 3 which is not supplied to the developing area and is prevented from proceeding by the doctor 6 is supplied to the toner hopper 8 by the internal pressure and gravity of the developer 3 in the developer accommodating section A. It moves toward the mouth 8a. The developer 3 that has moved to the vicinity of the toner supply port 8a is regulated by a pre-doctor 10, which is a second developer regulating member disposed on the upstream side of the doctor 6 in the developer transport direction.
Is attracted to the developing sleeve 4 side by the magnetic force of the developing sleeve 4, and is conveyed again to the doctor 6 side with the rotation of the developing sleeve 4, thereby circulating in the developer accommodating portion A.

In the developing device having the above structure, when the amount of toner 11 supplied to the developer 3 increases and the toner concentration increases, the bulk of the developer 3 increases accordingly. , And is regulated by the pre-doctor 10, but the developer 3 cannot be regulated completely.
a forms the developer retaining portion 3a and covers the opening of the toner supply port 8a. Therefore, the amount of toner taken into the developer 3 on the developing sleeve 4 is reduced. Due to this decrease in the amount of toner taken in, the toner density of the developer 3 is always kept below a certain density. Conversely, when the toner concentration of the developer 3 decreases, the bulk of the developer 3 decreases, and the developer stagnation portion 3a does not block the toner supply port 8a. The toner is taken in, and the toner density of the developer 3 is always maintained at a certain level or more.

When it is desired to change the toner concentration, the amount of the magnetic carrier accommodated in the developer accommodating section A is changed to adjust the bulk of the developer 3. For example, if the amount of the magnetic carrier is reduced from a certain amount, the bulk of the developer 3 is reduced, so that the intake of the toner 11 from the toner supply port 8a is increased and the toner concentration of the developer 3 is increased. As described above, in the developing device having the above configuration, the toner density can be controlled within a substantially constant range, so that a complicated toner density control unit using a toner density sensor, a toner replenishing member, or the like is unnecessary.

By the way, in the developing device having the above configuration, when the unused developing device is mounted on the printer body, the new developer 12 adjusted to a predetermined toner concentration in advance is used.
Is charged into the developer accommodating section A. FIG. 3 is a schematic configuration diagram illustrating an unused state of the developing device. Above the developer accommodating section A, a new developer accommodating section B for accommodating the new developer 12 is provided, and a seal 13 for separating the developer accommodating section A from the new developer accommodating section B is provided. At the time of mounting, the seal 13 is peeled off, and the new developer 12 charged into the developer accommodating portion A is uniformly carried on the developing sleeve 4 by the rotation of the developing sleeve 4.

Further, in the toner storage section 8, the toner aggregates in the toner supply port 8 a during transportation, or the toner hopper 8
In order to prevent the toner from being scattered from the toner, a seal 14 for separating the toner supply port 8a from the toner hopper 8 is provided. At the time of mounting, this seal 14
Is also peeled off, and toner supply to the developer 3 on the developing sleeve 4 is started.

Here, in the developing device according to the present embodiment, when an unused developing device is mounted on the printer main body, the agitator 9 starts rotating with respect to the rotation of the developing sleeve 4.
It has a control means for delaying the rotation start time of. FIG. 4 is a schematic configuration diagram of a drive gear and an agitator rotation gear in the developing device. As described above, when the unused developing device from which the seals 13 and 14 have been removed is mounted on the apparatus main body, the control unit 100 (FIG.
) Detects a mounting detection signal from the sensor 108 of the mounting section, and drives the developing means driving section 106 as a driving source of the developing sleeve 4 and the agitator 9. As shown in FIG. 4, the developing means driving section 106 rotates the driving gear 15 in the direction of arrow d, and simultaneously rotates the developing sleeve 4 in the direction of arrow b and the agitator rotating gear 16 in the direction of arrow c through the driving gear 15. Start rotating.

First, a first embodiment of the control means will be described. As the control means, an agitator 9
A clutch (not shown) for stopping the rotation of the developing sleeve 4 from the rotation of the developing sleeve 4 for a predetermined time is incorporated in the agitator 9. As the clutch, a conventionally known electromagnetic clutch or the like can be used. Even if the developing device is mounted on the main body of the printer and the developing sleeve 4 starts to rotate, the agitator 9 does not rotate by this clutch. After the new developer 12 is uniformly carried on the developing sleeve 4 by the rotation of the developing sleeve 4, the agitator 9 becomes rotatable, and the rotation of the agitator 9 replenishes the toner from the toner supply port 8a to the developing sleeve 4. The developer 3 on the developing sleeve 4 and the toner 11 come into contact for the first time. for that reason,
It is possible to prevent the toner concentration of the developer from partially increasing on the developing sleeve 4.

Next, a second embodiment of the control means will be described. FIG. 5 is a partial perspective view showing the configuration of the agitator rotating gear and the agitator. FIG. 6A is a main part side view for explaining how the agitator rotating gear idles, and FIG. 6B is a main part side view for explaining the state when the agitator rotation starts. As shown in FIG. 5, the agitator 9 has a male screw at the tip of the rotating shaft 9 a,
The agitator rotating gear 16 has a female screw shape at the tip of the rotating shaft 16a. In the unused developing device, the rotating shaft 9a of the agitator 9 and the agitator rotating gear 1
The rotation shaft 16a is screwed so as to be relatively movable in the axial direction. After the mounting, the agitator rotating gear 16 starts rotating in the direction of arrow c via the drive gear 15, and the agitator rotating gear 16 moves to the agitator 9 side. When the movement of the agitator rotating gear 16 stops and is completely screwed, the agitator 9 starts rotating.

Specifically, as shown in FIG. 6 (a), when not in use, the rotating shaft 16a of the agitator rotating gear 16 is screwed to the rotating shaft 9a of the agitator 9 so as to be relatively movable. Has become. Therefore, even if the developing sleeve 4 and the agitator rotating gear 16 start rotating simultaneously via the driving gear 15 after the mounting, the movement of the agitator rotating gear stops, and the rotating shaft 16a of the agitator rotating gear 16 is rotated.
Until the agitator 9 and the rotating shaft 9a of the agitator 9 are completely screwed, the agitator rotating gear 16 is idle and the agitator 9 does not rotate. Then, FIG.
When the movement of the agitator rotating gear 16 stops and the rotating shaft 16a of the agitator rotating gear 16 and the rotating shaft 9a of the agitator 9 are completely screwed, the agitator 9 starts rotating and the developing sleeve The toner supply to the developer 3 on the top 4 is started.

As described above, even after the developing sleeve 4 starts rotating after the developing device is mounted on the printer main body, the agitator 9
Does not rotate. After the new developer 12 is uniformly carried on the developing sleeve 4 by the rotation of the developing sleeve 4, the agitator 9 starts to rotate, and toner is supplied from the toner supply port 8 a to the developing sleeve 4. Developer 3 and toner 11 come into contact for the first time. Therefore, it is possible to prevent the toner concentration of the developer from partially increasing on the developing sleeve 4. Further, in the developing device having this configuration, it is not necessary to add a complicated component such as a clutch as a control unit.

The rotation stop time of the agitator 9 can be adjusted by the amount of screw tightening between the rotating shaft 9a of the agitator 9 and the rotating shaft 16a of the agitator rotating gear 16. If the screw tightening amount is small in the unused state, the agitator 9
The rotation stop time of the agitator 9 is shortened by increasing the screw tightening amount.

Next, the results of actual image formation using the developing device having the control means of the second embodiment will be described. First, 50 g of the developer having a toner concentration of 10% by weight was filled in the new developer accommodating section B, and 500 g of the toner was filled in the toner hopper 8. Then, the developing sleeve 4
Screw the agitator rotating gear 16 so that the rotating shaft of the agitator rotating gear 16 can move relative to the rotating shaft of the agitator 9 so that the agitator rotating gear 16 idles for about 5 seconds from the rotation of the agitator 9 (about 5 seconds when the agitator 9 stops). It was in the state that was done. Then, the seals 13 and 14 were peeled off, the developing device was mounted on the printer main body, and an image was formed under the following developing conditions.
When the toner density of the developer 3 was measured after forming three sheets (image ratio: 5%), the toner density was 12% by weight, and a good image could be obtained.

On the other hand, except that the rotating shaft of the agitator rotating gear 16 is completely screwed to the rotating shaft of the agitator 9 (the developing sleeve and the agitator rotate simultaneously), the developing conditions are the same as those described above. An image was formed. As a result, when the toner concentration of the developer 3 was measured after forming three sheets of images, the toner concentration was 20% by weight.
The background dirt image has occurred.

<Mechanical Conditions> Photoconductor linear velocity: 120 mm / sec Gap Gp between the developing sleeve and the photoconductor drum: 0.3 to
0.5 mm Gd1 between developing sleeve and doctor: 0.3 to 0.
5 mm Gd2 between developing sleeve and predoctor: 0.3 to
1.5 mm developing sleeve diameter: 16φ Ratio of linear speed of developing roller to linear speed of photoreceptor: 1.5 to 3.
0 <developer> Carrier: magnetite or iron: 40 to 50 μm Coverage of toner to carrier: 50 to 120% Charge amount Q / M: 10 to 30 μc / g Amount of magnetic carrier contained in developer accommodating section: 30 to
150g

Next, a third embodiment of the control means will be described. FIG. 7 is a schematic diagram showing a configuration of the agitator rotating gear 16 and the driving gear 17. As shown in FIG. 7, the drive gear 17 has a fan shape when viewed from the axial direction.
And the drive gear 17 are in a disengaged state. Therefore, even if the developing sleeve 4 starts rotating simultaneously with the rotation of the driving gear 17 after the mounting of the developing device, the agitator rotating gear 16 does not rotate until it engages with the driving gear 17. Thereafter, when the agitator rotating gear 16 and the driving gear 17 are engaged with each other, the agitator 9 starts rotating and toner supply to the developing sleeve 4 is started.

As described above, even if the developing sleeve 4 starts rotating after the developing device is mounted on the printer main body, the agitator 9 does not rotate because the agitator rotating gear 16 and the driving gear 17 do not engage with each other. After the new developer 12 is uniformly carried on the developing sleeve 4 by the rotation of the developing sleeve 4, the agitator 9 starts to rotate due to the engagement of the agitator rotating gear 16 and the driving gear 17, and the developing sleeve 8 When the toner is supplied to the developing sleeve 4, the developer 3 on the developing sleeve 4 and the toner 11 come into contact with each other for the first time. Therefore, it is possible to prevent the toner density from partially increasing on the developing sleeve 4. Further, in the case of this configuration, the agitator 9 rotates by the intermittent operation even during the normal toner supply, but this does not pose a problem because the agitator rotation speed required for the toner supply is secured.

In this embodiment, the driving gear 17 is used.
Is a fan shape when viewed from the axial direction, but is not particularly limited to this. For example, teeth are formed only in a predetermined rotation angle range so as to fit with the agitator 9 only in a predetermined rotation angle range. Drive gear may be used.

Further, in the present embodiment, the developing device having a configuration in which the seal 14 provided on the side of the toner replenishing port 8a is peeled off at the time of mounting and toner replenishment is started has been described. However, the present invention is not limited to this. For example, a toner storage portion for input is provided above the toner storage portion, and at the time of mounting, a seal member separating the toner storage portion and the toner storage portion for input is peeled off, so that the toner sealed in the toner storage portion for input is removed. The present invention may be applied to a developing device configured to be charged into the developing device.

[0043]

According to the first to sixth aspects of the present invention, after the developing device is mounted on the apparatus main body, the control means for delaying the start of rotation of the toner supply member with respect to the start of rotation of the developer carrier is provided. After the developer in the developer accommodating portion is uniformly carried on the developer carrying member by the rotation of the developer carrying member, the toner on the developer carrying member is replenished by the rotation of the toner supply member. Therefore, it is possible to prevent the toner concentration of the developer from being partially increased on the developer carrying member after mounting the developing device, and to obtain a good image without background contamination at the start of image formation. Has an excellent effect.

In particular, according to the second aspect of the present invention, the control means is provided with a clutch for stopping the rotation of the toner supply member for a predetermined time from the start of the rotation of the developer carrier. After the developer in the developer accommodating portion is uniformly carried on the developer carrying member by the rotation of the developer carrying member, the toner on the developer carrying member is replenished by the rotation of the toner supply member. Therefore, it is possible to prevent the toner concentration of the developer from being partially increased on the developer carrying member after mounting the developing device, and to obtain a good image without background contamination at the start of image formation. Has an excellent effect.

According to the third and fourth aspects of the present invention, the control means includes a rotating gear engaged with a driving gear rotating in conjunction with a driving source, and a rotating shaft of the rotating gear and rotation of the toner supply member. The shaft is screwed with a screw, at least before mounting, the rotating shaft of the rotary gear and the rotating shaft of the toner supply member are screwed in a relatively movable state, and when the relative movement stops after mounting and screwing is completed. Since the rotating shaft of the rotating gear and the rotating shaft of the toner supply member are integrally rotated, the developer in the developer accommodating portion is uniformly carried on the developer carrying member by the rotation of the developer carrying member. Later, toner is supplied to the developer on the developer carrier by rotation of the toner supply member. Therefore, it is possible to prevent the toner concentration of the developer on the developer carrier from being partially increased after the developing device is mounted, and it is possible to obtain a good image free from background smear at the start of image formation. Has an effect. Further, according to the present invention, there is no need to add a complicated component such as a clutch.

According to the fifth aspect of the present invention, the control means includes a drive gear which rotates in conjunction with the drive source and engages with the rotation gear of the toner supply member only within a predetermined rotation angle range. Before, since the driving gear and the rotating gear of the toner supply member are in a non-fitting state,
After the developer in the developer accommodating portion is uniformly carried on the developer carrying member by the rotation of the developer carrying member, the toner on the developer carrying member is replenished by the rotation of the toner supply member. Therefore, it is possible to prevent the toner concentration of the developer on the developer carrier from being partially increased after the developing device is mounted, and it is possible to obtain a good image free from background smear at the start of image formation. Has an effect. Further, according to the present invention, there is no need to add a complicated component such as a clutch.

According to the sixth aspect of the present invention, the second developer regulating member regulates the passage of the developer and controls the incorporation of the toner into the developer on the developer carrying member. There is an excellent effect that the toner concentration of the agent can always be kept in a substantially constant range.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a developing device according to an embodiment.

FIG. 2 is a control block diagram including a control unit of the developing device.

FIG. 3 is a schematic configuration diagram illustrating an unused state of the developing device.

FIG. 4 is a schematic configuration diagram of a driving gear and an agitator rotating gear of the developing device.

FIG. 5 is a partial perspective view illustrating a schematic configuration of a developing device according to a second embodiment.

FIG. 6A is a side view of a main part for explaining how an agitator rotating gear of the developing device idles. (B) is a principal part side view explaining the situation at the time of agitator rotation start.

FIG. 7 is a schematic diagram showing a schematic configuration of an agitator rotating gear and a driving gear of a developing device according to a third embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photosensitive drum 2 developing casing 3 developer 4 developing sleeve 5 magnet roller 6 doctor 7 developer storage case 8 toner hopper 8a toner supply port 9 agitator 10 predoctor 11 toner 12 initial developer 13 seal 14 seal 15 drive gear 16 agitator rotating gear 17 Drive gear A Developer storage section B Initial developer storage section

Claims (6)

[Claims] 1. A developer carrying member having a first magnetic field generating means therein for carrying and transporting a two-component developer containing a toner and a magnetic carrier, and carrying the developer carried by the developer carrying member. A developer regulating member for regulating the amount of developer to be supplied, a developer accommodating portion for accommodating the developer scraped off by the developer regulating member, and a developer of the developer carrier in the developer accommodating portion. A toner container having a toner replenishing port adjacent from the upstream side in the conveying direction and having a toner supply port so that the stored toner comes into contact with the developer on the developer carrying member; An image forming apparatus including a developing device having a toner supply member for supplying to a replenishing port, wherein a developer is charged into the developer accommodating portion when the unused developing device is mounted on the apparatus main body; Relative to the start of rotation of the developer carrier An image forming apparatus, comprising a control means for delaying the start of rotation of the toner supply member. 2. The image forming apparatus according to claim 1, wherein the control means includes a clutch for stopping rotation of the toner supply member for a predetermined time from the start of rotation of the developer carrier. Characteristic image forming apparatus. 3. The image forming apparatus according to claim 1, wherein the control means includes a rotating gear engaged with a driving gear that rotates in conjunction with a driving source, and a rotating shaft of the rotating gear and the toner supply member. The rotating shaft is screwed with a screw, at least before mounting, the rotating shaft of the rotating gear and the rotating shaft of the toner supply member are screwed in a relatively movable state, and after the mounting, the relative movement is performed by rotation of the rotating gear. The rotation shaft of the rotation gear and the rotation shaft of the toner supply member rotate integrally when the screwing is completed and the screwing is completed. 4. The image forming apparatus according to claim 3, wherein the developer in the developer accommodating portion is uniformly carried on the developer carrier, and then the rotation shaft of the rotation gear and the rotation of the toner supply member are rotated. An image forming apparatus, wherein the shaft and the shaft start rotating together. 5. The image forming apparatus according to claim 1, wherein the control means includes a drive gear that rotates in conjunction with a drive source and engages with the rotation gear of the toner supply member only within a predetermined rotation angle range. The image forming apparatus is characterized in that the driving gear and the rotating gear of the toner supply member are not engaged at least before mounting. 6. The image forming apparatus according to claim 1, wherein said developer accommodating portion includes a second developer regulating member disposed upstream of said first developer regulating member in a developer conveying direction. The second developer regulating member regulates the passage of the increased amount of the developer when the toner concentration of the developer on the developer carrier increases and the layer thickness of the developer increases. In order to
An image forming apparatus, wherein a distance from the developer carrier is set.