JPH09138552A - Two-component dry developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-component dry developing device enabling a user to replace developer in a short time. SOLUTION: When a developer discharging screw 15 is rotated after making the developer discharging port 18 of a developer discharging part 17 agree with the developer discharging port 22 of a cover 21, the deteriorating developer 4 is carried from a developer container 8 and the deteriorating developer 4 passes through the developer discharging ports 18 and 22, then, the developer 4 drops into a developer recovering bottle 19 so as to be recovered. At this time, a paddle roller in the developer container 8 is rotated slower than normal, and the developer is blocked from being carried from the paddle roller to a developing sleeve, then, a developing material replacing time is shortened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry developing device for an electrophotographic image forming apparatus using a two-component developer such as a copying machine, a printer, a facsimile, or the like, that is, a two-component dry developing device.

[0002]

2. Description of the Related Art A two-component dry developing device is known as a kind of dry developing device for an image forming apparatus using an electrophotographic system such as a copying machine or a printer. In this two-component dry developing device, a two-component developer formed by mixing toner and carrier is used as a developer for visualizing the latent image formed on the latent image carrier.

In a dry developing device using a two-component developer obtained by mixing toner and carrier, as the image forming operation such as copying or printing is repeated, the amount of the developer contained in the developing container is increased. The toner is sequentially consumed, and the toner runs out. Therefore, in order to always maintain the toner concentration in the developer, that is, the mixing ratio of the toner and the carrier at the optimal concentration for development, toner is replenished in the developing container at appropriate times.

In the above-mentioned conventional dry developing device, the toner replenishment into the developing container is configured to be relatively easily performed by a user side operator by a toner replenishing means such as a toner cartridge as well known. There is.

Further, in a dry developing device using a two-component developer prepared by mixing toner and carrier, the carrier and the toner and constituent members inside the developing device are contacted with each other, and the carriers are contacted with each other. The carrier also gradually deteriorates, resulting in, for example, toner filming, crushing, breakage of the coat film formed on the surface of the carrier, and the like, and the developing ability of the developer may be significantly impaired. Therefore, in this type of dry developing device, in order to always maintain the developing ability of the developer in the developing container at a predetermined level, the deteriorated carrier is discharged to the outside of the developing container in a timely manner, and inside the developing container, At the appropriate time, a replacement developer, that is, a new developer is supplied.

However, replacing the developer in the developing container in the conventional dry developing device requires a relatively difficult work such as removing the cover of the developing device. Therefore, the structure and function of the developing device should be well understood. I had no choice but to depend on the service person who was there. Further, the replacement work of the developer in the conventional dry developing device requires a considerable amount of work time even if a service person performs it, which is inefficient work.

Therefore, in order to eliminate the trouble and trouble of replacing the developer in these conventional dry developing devices,
In Japanese Patent Publication No. 5-73019, cylindrical cartridges are prepared for both toner storage and developer storage, and different types of cartridges are common to a cylindrical support attached to the upper part of a developing container. It proposes a technique in which a toner storage cartridge or a developer storage cartridge is selected and used when toner is replenished or a developer is supplied, replaced, or stored. According to this dry developing device, not only replenishment of toner but also supply, replacement and storage of the developer can be easily performed by the user of the dry developing device, but the deteriorated developer is discharged to the outside of the developing container. In doing so, there is a problem that the developer on the developing sleeve is difficult to separate and the work takes time.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a two-component dry developing device in which a user or a service person can replace the developer in a short time. To do.

[0009]

A two-component dry developing device according to the present invention comprises a developing container disposed near a developing portion of a latent image carrier and a developing container in the developing container. In a two-component dry developing device having a paddle roller for supplying the contained developer to a developing roller and a means for carrying the developer out of the developing container, when the developer is carried out of the developing container, The rotation speed of the paddle roller is slower than usual.

A two-component dry developing device according to the present invention is a developing device which is disposed in the vicinity of a developing portion of a latent image carrier and a developer which is contained in the developing container and is used as a developing roller. In a two-component dry developing device having a paddle roller for supplying and a means for carrying out the developer to the outside of the developing container, a developing container disposed in the vicinity of the developing portion of the latent image carrier, and housed in the developing container. In a two-component dry developing device having a paddle roller for supplying the developer to the developing roller and a means for carrying the developer out of the developing container, when the developer is carried out of the developing container, a normal rotation is first performed. The paddle roller is rotated at a speed, and the rotation speed of the paddle roller is decreased after a predetermined time has elapsed.

According to a third aspect of the two-component dry developing device of the present invention, the developing container is disposed in the vicinity of the developing portion of the latent image carrier, and the developer contained in the developing container is used as a developing roller. In a two-component dry developing device having a supplying paddle roller and a means for carrying out the developer to the outside of the developing container, it is possible to stop the rotation of the paddle roller when carrying out the developer to the outside of the developing container. Is characterized by.

According to a fourth aspect of the two-component dry developing device of the present invention, the developing container is disposed in the vicinity of the developing portion of the latent image carrier, and the developer contained in the developing container is used as a developing roller. In a two-component dry developing device having a paddle roller for supplying and a means for carrying out the developer to the outside of the developing container, when carrying out the developer to the outside of the developing container, first rotate the paddle roller, and after a predetermined time elapses. The rotation of the paddle roller is stopped, and the rotating bodies other than the paddle roller are continuously rotated for a predetermined time.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a two-component dry developing apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view of a two-component dry developing device according to this embodiment. An image forming apparatus equipped with this dry developing device is an image forming apparatus using a well-known electrophotographic process, and includes a charger (not shown) and an exposure image irradiating means around a cylindrical photosensitive drum 1 which is a latent image carrier. A dry developing device 2, a transfer device (not shown), a cleaning device, and a charge eliminating device are arranged.

The operation of this image forming apparatus will be described. First, the surface of the photoconductor drum 1 is uniformly charged by a charger (not shown), and then exposure and irradiation are performed to form an electrostatic latent image on the surface of the photoconductor drum 1. This electrostatic latent image is formed into a toner image (visualized) by the dry developing device 2 and then transferred onto a transfer sheet by a transfer device (not shown). The transfer paper on which the toner image has been transferred is sent to a fixing device (not shown), where the image is fixed and discharged as a copy or printed matter onto a tray (not shown) outside the machine. On the other hand, after the transfer of the toner image, the photosensitive drum 1 is cleaned by a cleaning device (not shown) to remove foreign substances such as residual toner and paper dust, and then removed by a charge removing device (not shown). , It returns to the initial state for image formation again.

In FIG. 1, the dry developing device 2 includes developing sleeves 5 and 6 rotatably mounted near the opening in a developing container 8 having an opening in a portion adjacent to the surface of the photosensitive drum 1. A doctor 7 mounted above the developing sleeve 5, a paddle roller 10 having a large number of blades rotatably mounted on the back of the developing sleeves 5 and 6, a separator 11 provided above the paddle roller 10, and a paddle roller 10 It has a cylindrical stirring roller 9 rotatably attached to the back of the developer and a developer concentration detector 23 (T sensor) attached below the stirring roller 9. A well-known developing roller having a magnet inside is used as the developing sleeves 5 and 6.

Further, a developer replenishing screw 16 is arranged above the developing container 8, and the developer replenishing screw 1 is provided.
A conveying screw 12 is rotatably attached below the developing container 6, and a developer discharging screw 15 is provided below the developing container 8.
Is arranged. Further, a toner transfer / agitation roller 14 and a toner replenishing roller 13 are attached to the inner side of the developing container 8 opposite to the opening. Of course, the developer 3 is stored inside the developing container 8.

The dry developing device 2 in this embodiment uses a two-component magnetic brush developing system, and the developer 3 is
The toner and carrier are mixed in a mixing ratio of 1.5 to 6.0% by weight. Similarly to the developer 3, the replacement developer is also composed of toner and carrier, and the mixture ratio thereof is adjusted to the initial setting of the image forming apparatus. The developer 3 is transferred to the developing sleeves 5 and 6 while being stirred by the stirring roller 9 and the paddle roller 10 inside the developing container 8.

In the dry developing device using this type of two-component developer, as described above, as the image forming operation such as copying or printing is repeated, the carrier and the toner and the constituent members inside the developing device are separated from each other. Due to the contact and the contact between the carriers, the carrier in the developing container 8 is gradually deteriorated, resulting in, for example, toner filming, crushing, and breakage of the coat film applied to the surface of the carrier.
The developing ability of the developer 3 is significantly impaired.

Therefore, in the dry developing device of this embodiment,
As shown in FIG. 1, the developer discharge screw 15 discharges the deteriorated developer to the outside of the developing container 8 at a proper time, and the developer replenishing screw 16 discharges the new developer into the developing container 8. To maintain the developing ability of the developer 3 inside the dry developing device 2 at a predetermined level.

FIG. 2 is a schematic sectional view showing a mechanism for discharging the deteriorated developer in the dry developing apparatus of this embodiment. A cylindrical developer discharging portion 17 is provided on the front side plate 25 of the developing container 8 in a protruding manner, and a developer discharging port 22 is opened on a lower surface near the tip of the developer discharging portion 17. Developer discharging section 17
A developer discharging screw 15 having a spiral fin attached around the shaft is rotatably attached inside. Further, a cylindrical cover 21 having a bottom is fitted to the outside of the developer discharging portion 17 via a seal 20. A developer discharge port 22 is opened on the lower surface near the bottom of the cover 21. On the other hand, an opening 24 for inserting the cover 21 is provided on the side surface of the developer recovery bottle 19.

When the developer 3 stored in the developing container 8 is deteriorated, the developer discharging portion 17 provided on the front side plate 25 of the developing container 8 is connected to the developer collecting bottle as shown in FIG. 2A. It is inserted into the opening 24 of 19. Then, the cover 21
2A comes into contact with the inside of the opposite side surface of the developer recovery bottle 19 to reach the state shown in FIG. 2B.

After the developer discharge port 18 of the developer discharge unit 17 and the developer discharge port 22 of the cover 21 are aligned and opened,
The developer discharging screw 1 is generated by an ON signal of a developer discharging switch (not shown) or a collection bottle set detection switch.
Rotate 5 The deteriorated developer 4 is conveyed from the inside of the developing container 8 by the rotation of the developer discharge screw 15, and the deteriorated developer 4 is dropped into the developer recovery bottle 19 through the developer discharge ports 18 and 22 to be collected.

Here, if the rotation of the paddle roller 10 of FIG. 1 is slowed, the developer 3 is not transferred to the developing sleeve 5, and as a result, the developer on the developing sleeve 5 is quickly discharged. The rotation speed of the paddle roller 10 at which the developer is not transferred from the paddle roller 10 to the developing sleeve 5 varies depending on the arrangement configuration of the dry developing device, but, for example, when tested by the present inventors, the paddle roller 10
When the rotation speed of No. 1 was set to 60% or less of the normal rotation speed, the transfer of the developer from the paddle roller 10 to the developing sleeve 5 was stopped.

In the second embodiment, after the large amount of developer is discharged without slowing down the speed of the entire dry developing device including the paddle roller 10, the speed of the whole dry developing device including the paddle roller 10 is reduced. Paddle roller 10
The transfer of the developer from the developing sleeve to the developing sleeve 5 is stopped. As a result, the developer on the developing sleeve 5 is quickly discharged, and the discharge time of the developer can be shortened.

Further, in the third embodiment, a clutch for stopping the paddle roller 10 is provided, the rotation of the paddle roller 10 is stopped when the developer is collected, and the developer from the paddle roller 10 to the developing sleeve 5 is stopped. Stop the transfer of. As a result, the developer on the developing sleeve 5 can be quickly discharged, and the developer discharging time can be shortened.

In the fourth embodiment, the entire dry developing apparatus including the paddle roller 10 is driven for a predetermined time to discharge a large amount of developer, and then the paddle roller 1
Only 0 is stopped, and the developer on the developing sleeve 5 is discharged. This makes it possible to shorten the developer discharge time.

[0027]

According to the two-component dry developing apparatus of the first aspect, when the developer is carried out of the developing container, the rotation speed of the paddle roller is set to be slower than the normal rotation. There is an effect that the replacement work of the developer can be performed in a short time without providing a special mechanism.

According to the two-component dry developing device of the second aspect, when the developer is carried out of the developing container, the paddle roller is first rotated at a normal rotation speed, and after a predetermined time elapses, the rotation speed of the paddle roller is changed. I tried to slow it down,
By performing timing control or the like, it is possible to further shorten the developer replacement work time as compared with the two-component dry developing device according to the first aspect.

According to the two-component dry developing apparatus of the third aspect, the rotation of the paddle roller can be stopped when the developer is carried out of the developing container. Therefore, a rotation stopping mechanism for the paddle roller is provided. There is an effect that the developer replacement work time can be further shortened as compared with the two-component dry developing device according to the second aspect.

According to the two-component dry developing apparatus of the fourth aspect, when the developer is carried out of the developing container, the paddle roller is first rotated, and after a predetermined time has elapsed, the paddle roller is stopped from rotating and the parts other than the paddle roller are stopped. Since it was made to rotate for a predetermined time continuously, by providing a rotation stop mechanism for the paddle roller and performing timing control,
There is an effect that the developer replacement work time can be further shortened as compared with the two-component dry developing device according to the third aspect.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an embodiment of a two-component dry developing device according to the present invention.

FIG. 2 is a schematic cross-sectional view showing a mechanism for discharging deteriorated developer in the dry developing device of FIG.

[Explanation of symbols]

 1 Photosensitive Drum 2 Dry Development Device 3 Developer 4 Deteriorated Developer 5, 6 Development Sleeve 7 Doctor 8 Development Container 9 Stir Roller 10 Paddle Roller 11 Separator 12 Conveyor Screw 13 Toner Supply Roller 14 Toner Transfer / Stir Roller 15 Developer Discharge Screw 16 Developer supply screw 17 Developer discharge part 18 Developer discharge port 19 Developer recovery bottle 20 Seal 21 Cover 22 Developer discharge port 23 Developer concentration detector 24 Opening 25 Front plate

Claims (4)

[Claims] 1. A developing container arranged in the vicinity of a developing portion of a latent image carrier, a paddle roller for supplying a developer contained in the developing container to a developing roller, and developing outside the developing container. A two-component dry developing device having a means for carrying out the developer, wherein the rotation speed of the paddle roller is slower than usual when the developer is carried out of the developing container. . 2. A developing container disposed in the vicinity of the developing portion of the latent image carrier, a paddle roller for supplying the developer contained in the developing container to a developing roller, and a means for carrying the developer out of the developing container. And a paddle roller for supplying the developer contained in the developing container to the developing roller, and a developing container outside the developing container. In a two-component dry developing device having a means for discharging the developer to, when discharging the developer to the outside of the developing container, first rotate the paddle roller at a normal rotation speed, and after a lapse of a predetermined time, move the paddle roller. A two-component dry developing device characterized by slowing the rotation speed. 3. A developing container arranged in the vicinity of the developing portion of the latent image carrier, a paddle roller for supplying the developer contained in the developing container to a developing roller, and a means for carrying the developer out of the developing container. In the two-component dry developing device having the following, the two-component dry developing device can stop the rotation of the paddle roller when the developer is carried out of the developing container. 4. A developing container arranged in the vicinity of the developing portion of the latent image carrier, a paddle roller for supplying the developer contained in the developing container to a developing roller, and a means for carrying the developer out of the developing container. In a two-component dry developing apparatus having and, when the developer is carried out to the outside of the developing container, the paddle roller is first rotated, the rotation of the paddle roller is stopped after a predetermined time elapses, and the rotating body other than the paddle roller is continued. A two-component dry developing device which is rotated for a predetermined time.