JPH09138579A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device equipped with a recovered-toner carrying device which removes carrier in recovered toner, thereby preventing the occurrence of void. SOLUTION: A magnet 12 is set on the bottom of a recovered-toner storage part 11, and above the bottom a toner carrying member 13 of an endless- circulation-belt canying type runs by means of rotary shafts 20 provided at both its ends. Scraping/carrying blades are attached to the outside of the belt in such a way as to project obliquely. The blades run above the bottom of the recovered-toner storage part and carry recovered toner, also the recovered toner comes into contact with the magnet 12 set on the bottom of the recovered- toner storage part 11, magnetic carrier in the recovered toner is attracted to the magnet 12, and the carrier is thus removed from the recovered toner.

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 adopting a toner recycling system.

[0002]

2. Description of the Related Art Copiers, facsimiles, printers that form a toner image on a photosensitive drum, transfer the toner image to a transfer material, and then collect and reuse the toner remaining on the photosensitive drum. In an image forming apparatus such as the above, particularly in an image forming apparatus that forms an image using a two-component developing device, toner (hereinafter referred to as collected toner) obtained by removing residual toner on a photosensitive drum by a cleaning unit is toner. Many image forming apparatuses have been proposed that employ a so-called toner recycling method in which the toner is returned to the developing device by a conveying means and is reused.

As a conventional image forming apparatus of this type, in JP-A-6-308830, a spiral fin is provided inside the collected toner conveying path to prevent toner from fusing due to frictional heat, and further to convey pipe end. There is disclosed an image forming apparatus in which a bar-shaped magnet is detachably attached to a portion and a carrier and toner can be separated from collected toner.

In the toner recycling, the collected toner from which the residual toner on the photosensitive drum is removed by the cleaning means is conveyed to the developing section and reused. The collected toner has a higher heat and pressure than the unused toner. In addition, since the toner is subjected to stress such as friction and has a high degree of aggregation, there is a problem that the replenishment amount decreases when the toner is replenished, and a background stain amount increases. Therefore, there is proposed an image forming apparatus capable of preventing deterioration of image quality by keeping the mixing ratio of the collected toner to the unused toner low.

[0005]

However, when the carrier in the developing device adheres to the photosensitive drum and is collected by the cleaning means, the carrier is mixed in the collected toner, and the carrier of the collected toner conveying means is collected. In the inside, the collected toner and the carrier are subjected to stress such as heat, pressure and friction, and carrier nucleation aggregation toner in which the fine powder toner surrounds the carrier is generated. When the carrier nucleation agglomerated toner is returned to the developing device, it is not developed into a line image but is developed into a solid image and is sandwiched between the transfer material and the photoconductor in the transfer step of transferring the toner image to the transfer material. However, a gap is formed between the image material on which the normal toner is developed and the transfer material. As a result, the carrier nucleation agglomerated toner and the toner around it are not transferred to the transfer material, and there is a problem that an abnormal image that appears as a white circle occurs.

The present invention has been made in view of the above-mentioned problems of the prior art, and provides a collected toner conveying device capable of removing the carrier in the collected toner and preventing the occurrence of the above-mentioned defects such as white spots. An object of the present invention is to provide an image forming apparatus provided with the image forming apparatus.

[0007]

According to a first aspect of the present invention, there is provided an image forming apparatus, wherein a toner image is formed on a photosensitive drum, and the toner image is transferred onto a transfer material.
In the image forming apparatus for collecting and reusing the toner remaining on the photosensitive drum, a magnetic member is provided in the toner collecting device, and the magnetic member is brought into contact with the collected toner.

A second aspect of the present invention is an image forming apparatus.
The magnetic member is a magnet provided on the bottom surface of the toner collecting device, and a coil spring-shaped conveying means is installed above the bottom surface.

According to another aspect of the present invention, there is provided an image forming apparatus.
The above-mentioned magnet is characterized in that the magnet is a rod-shaped magnet extending in the rotation axis direction of the coil-spring-shaped conveying means.

According to another aspect of the present invention, there is provided an image forming apparatus.
The magnetic member is a magnet provided on the bottom surface of the toner collecting device, and a toner conveying means having a blade for scraping and conveying on the outer surface of the endless circulation belt is provided above the bottom surface. It is characterized in that it is installed so that the toner conveying means runs above the bottom surface.

[0011]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of an image forming apparatus according to the present invention will be described below with reference to the drawings. The image forming apparatus according to the present embodiment will be described assuming that a two-component magnetic developer including a non-magnetic toner and a magnetic carrier is used as a developer and the magnetic carrier removes the magnetic carrier from the collected toner.

FIG. 1 is a schematic view of an embodiment of an image forming apparatus according to the present invention. A charging member 2, an exposing unit 3, an eraser 4, a developing unit 5, a transferring unit 6, a cleaning unit 7 and a charge eliminating lamp 9 are arranged around a cylindrical photosensitive drum 1, and a space between the cleaning unit 7 and the developing unit 5 is arranged between them. They are connected by the collected toner conveying means 8.

The normal copying operation of the image forming apparatus of this embodiment will be described. When the copy start key is pressed, a voltage is applied to the charging member 2 from a charging power bag (not shown) to uniformly charge the surface of the photosensitive drum 1 to a predetermined potential. Next, an original is read by a scanner (not shown), the photoconductor drum is exposed by the exposure unit 3 to form an electrostatic latent image, and subsequently, it is developed by the developing unit 5 to develop toner on the surface of the photoconductor drum 1. Form an image.
After that, the transfer unit 6 transfers the toner image onto the transfer paper. The transfer sheet is conveyed to the fixing device 10 by the conveying unit, the transferred toner image is fixed, and the sheet is ejected to the outside of the apparatus. On the other hand, on the surface of the photoconductor drum 1 after the transfer, the untransferred transfer residual toner and the paper dust attached when the transfer paper comes into contact with the photoconductor remain. The cleaning unit 7 removes the transfer residual toner and paper dust from the photosensitive drum 1.
After removing from above, the charge removal lamp 9 removes the charge on the photosensitive drum 1 to return to the image formation start state. The collected toner is temporarily stored in the collected toner storage unit 11, and then is conveyed to the toner hopper 17 in the developing device 5 by the collected toner conveying unit 8.

FIG. 2 is a plan view of the collected toner conveying means of the embodiment shown in FIG. The collected toner conveying means 8 is mainly composed of conveying members 13 and 15 composed of coil springs, driving means for rotationally driving the conveying members 13 and 15, and a conveying pipe 14. The conveying member 13 is installed in the collected toner storage unit 11 in parallel with the rotation axis of the photosensitive drum 1.
Although one end of the collected toner storage unit 11 is fitted to the transport pipe 14, the transport unit 15 is installed in the transport pipe 14. The rotational driving force of the transport member 13 in the collected toner storage unit 11 is transmitted to the transport member 15 in the transport pipe 14 by, for example, the gear mechanism 24 or the like.

The carrying member 15 is for carrying the collected toner obliquely upward so that the carrying of the collected toner is not delayed. Therefore, the number of rotations of the carrying member 15 is larger than that of the carrying member 13 in the collected toner storage section 11. The conveying member 15 conveys the collected toner to a position above the toner hopper 17 in the developing device 5, and replenishes the collected toner into the toner hopper 17 from the collected toner supply port 18.

FIG. 3 is a sectional view of the collected toner storage portion 11 of the embodiment shown in FIG. A magnet 12 is installed on the bottom surface of the gutter-shaped collected toner storage portion 11, a conveying member 13 is arranged above the bottom surface, and the conveying member 13 is rotated in the arrow direction in FIG. It is designed to convey toner. That is, the toner collected by the cleaning means 7 in the collected toner storage unit 11 contacts the magnet 12 installed on the bottom surface of the collected toner storage unit 11 while being transported by the rotation of the toner transport member 13. Therefore, the magnetic carrier in the collected toner is adsorbed by the magnet 12 in a state where the toner is attached to the surroundings and is removed from the collected toner.

FIG. 4 is a perspective view of a collected toner storage portion 11a of another embodiment of the image forming apparatus according to the present invention. The collected toner storage section 11a has a magnet 12 installed on the bottom surface.
Above the bottom surface, there is an endless circulation belt transfer type transfer member 13a.
Are provided so as to travel by the rotary shafts 20 at both ends.
On the outer surface of the belt 21, blades 22 for scraping and conveying are provided to project obliquely. That is, as the belt 21 rotates and runs, the blades 22 on the outer surface of the belt 21 also run above the bottom surface of the collected toner storage portion 11, thereby carrying the toner collected by the cleaning means 7. The removal of the magnetic carrier from the collected toner by the magnet 12 is the same as in the previous embodiment, and thus the description thereof is omitted, but the blade 22
Since the toner can be pushed away, the surface of the magnet 12 is always cleaned, and in that state, the recovered toner mixed with new carrier can be brought into contact therewith, so that the carrier removing effect is enhanced.

FIG. 5 is a perspective view of a conveying member 13b of still another embodiment of the image forming apparatus according to the present invention. The coil-spring-shaped transport member 13b has a round bar-shaped magnet 16 extending in the axial direction at the center thereof. Further, a gear 23 to be coupled to a driving means (not shown) is provided at one end of the transport member 13b. Other configurations and operations are the same as those in the previous embodiment, and thus duplicated description will be omitted.

[0019]

According to the image forming apparatus of the first aspect,
Since a magnetic member is provided in the toner collecting device and this magnetic member comes into contact with the collected toner, the magnetic carrier mixed in the collected toner can be removed, carrier nucleation aggregation toner is not generated, and white spots on a solid image are prevented. The effect is that you can.

According to the image forming apparatus of the second aspect, since the magnet is installed on the bottom surface of the toner collecting device and the coil spring-like conveying means is installed above the bottom surface, the carrier mixed in the collected toner is removed. Therefore, there is an effect that carrier nucleus aggregation toner is not generated and white spots on a solid image can be prevented.

According to the image forming apparatus of the third aspect, since the rod-shaped magnet extending in the rotation axis direction of the coil-spring-shaped conveying means is provided, the carrier mixed in the collected toner can be removed, and the carrier core agglomerated toner. It is possible to prevent white spots on a solid image without being generated.

According to the fourth aspect of the present invention, there is provided the toner conveying means in which the magnet is installed on the bottom surface of the toner collecting device, and the scraping and conveying blades are attached to the outer surface of the endless circulation belt so as to protrude above the bottom surface. Since it travels in the direction of, the carrier mixed in the collected toner can be removed, carrier nucleation aggregation toner is not generated, and there is an effect that white spots on a solid image can be prevented. There is an effect that it can be removed properly and the cleaning function of the magnet becomes unnecessary.

[Brief description of the drawings]

FIG. 1 is a schematic view of an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a plan view of a collected toner conveying unit of the embodiment shown in FIG.

FIG. 3 is a cross-sectional view of a collected toner storage unit of the embodiment of FIG.

FIG. 4 is a perspective view of a collected toner storage section of another embodiment of the image forming apparatus according to the present invention.

FIG. 5 is a perspective view of a conveying member of still another embodiment of the image forming apparatus according to the present invention.

[Explanation of symbols]

 1 Photoconductor Drum 2 Charging Member 3 Exposure Means 4 Eraser 5 Developing Means 6 Transfer Means 7 Cleaning Means 8 Collecting Toner Conveying Means 9 Electrification Lamp 10 Fixing Device 11, 11a Collecting Toner Storage 12 Magnets 13, 13a, 13b Conveying Members 14 Conveying Pipe 15 Conveying member 16 Magnet 17 Toner hopper 18 Collected toner replenishing port 19 Conveying means 20 Rotating shaft 21 Belt 22 Blade 23 Gear 24 Gear mechanism

Claims (4)

[Claims] 1. An image forming apparatus for forming a toner image on a photosensitive drum, transferring the toner image to a transfer material, and then collecting and reusing the toner remaining on the photosensitive drum. An image forming apparatus, wherein a magnetic member is provided in the collecting device, and the magnetic member is brought into contact with the collected toner. 2. The image forming apparatus according to claim 1, wherein the magnetic member is a magnet provided on a bottom surface of the toner collecting device, and a coil spring-shaped conveying unit is installed above the bottom surface. 3. The image forming apparatus according to claim 2, wherein the magnet is a bar-shaped magnet extending in a rotation axis direction of the coil spring-shaped conveying means. 4. The toner carrying means, wherein the magnetic member is a magnet provided on a bottom surface of the toner collecting device, and a blade for scraping and carrying is projectingly provided on an outer surface of the endless circulation belt above the bottom surface. The image forming apparatus according to claim 1, wherein the image forming apparatus is installed and the toner conveying means is configured to run above the bottom surface.