Image forming device

Patent metadata

Field	Value
Publication number	US-2020310277-A1
Application number	US-201916520689-A
Country	US
Kind code	A1
Filing date	Jul 24, 2019
Priority date	Mar 29, 2019
Publication date	Oct 1, 2020
Grant date	—

Abstract

An image forming device includes: a developer holder that is rotatably arranged opposing a latent image holder holding an electrostatic latent image, holds developer including carrier and toner charged to a predetermined regular polarity, has a potential of the same polarity as the regular polarity applied thereto, and develops the electrostatic latent image using the toner; an opposite electrode that is arranged opposing the developer holder with a predetermined gap therebetween; and a controller that changes at least one of a potential applied to the opposite electrode and a rotation direction of the opposite electrode in accordance with an area coverage of the electrostatic latent image of the latent image holder.

First claim

What is claimed is:

1 . An image forming device comprising:
a developer holder that is rotatably arranged opposing a latent image holder holding an electrostatic latent image, holds developer including carrier and toner charged to a predetermined regular polarity, has a potential of the same polarity as the regular polarity applied thereto, and develops the electrostatic latent image using the toner; an opposite electrode that is arranged opposing the developer holder with a predetermined gap therebetween; and a controller that changes at least one of a potential applied to the opposite electrode and a rotation direction of the opposite electrode in accordance with an area coverage of the electrostatic latent image of the latent image holder.

2 . The image forming device according to claim 1 ,
wherein the opposite electrode is arranged further downstream in a rotation direction of the developer holder than a section where the developer holder and the latent image holder oppose each other, and adsorbs the toner that has adhered to a surface of the developer holder.

3 . The image forming device according to claim 2 ,
wherein the opposite electrode is arranged with the gap with the developer holder being narrower than a gap between the latent image holder and the developer holder.

4 . The image forming device according to claim 2 ,
wherein the opposite electrode is arranged in a position where the gap with the developer holder is minimized, opposing a magnetic pole of the developer holder.

5 . The image forming device according to claim 3 ,
wherein the opposite electrode is arranged in a position where the gap with the developer holder is minimized, opposing a magnetic pole of the developer holder.

6 . The image forming device according to claim 1 ,
wherein, in a case where the area coverage is lower than a predetermined threshold value, the controller applies, to the opposite electrode, a potential having the same polarity as the regular polarity and an absolute value that is larger than that of the developer holder.

7 . The image forming device according to claim 2 ,
wherein, in a case where the area coverage is lower than a predetermined threshold value, the controller applies, to the opposite electrode, a potential having the same polarity as the regular polarity and an absolute value that is larger than that of the developer holder.

8 . The image forming device according to claim 3 ,
wherein, in a case where the area coverage is lower than a predetermined threshold value, the controller applies, to the opposite electrode, a potential having the same polarity as the regular polarity and an absolute value that is larger than that of the developer holder.

9 . The image forming device according to claim 4 ,
wherein, in a case where the area coverage is lower than a predetermined threshold value, the controller applies, to the opposite electrode, a potential having the same polarity as the regular polarity and an absolute value that is larger than that of the developer holder.

10 . The image forming device according to claim 5 ,
wherein, in a case where the area coverage is lower than a predetermined threshold value, the controller applies, to the opposite electrode, a potential having the same polarity as the regular polarity and an absolute value that is larger than that of the developer holder.

11 . The image forming device according to claim 1 ,
wherein, in a case where the area coverage is higher than a predetermined threshold value, the controller applies, to the opposite electrode, a potential having the same polarity as the regular polarity and the same magnitude as that of the developer holder.

12 . The image forming device according to claim 2 ,
wherein, in a case where the area coverage is higher than a predetermined threshold value, the controller applies, to the opposite electrode, a potential having the same polarity as the regular polarity and the same magnitude as that of the developer holder.

13 . The image forming device according to claim 3 ,
wherein, in a case where the area coverage is higher than a predetermined threshold value, the controller applies, to the opposite electrode, a potential having the same polarity as the regular polarity and the same magnitude as that of the developer holder.

14 . The image forming device according to claim 4 ,
wherein, in a case where the area coverage is higher than a predetermined threshold value, the controller applies, to the opposite electrode, a potential having the same polarity as the regular polarity and the same magnitude as that of the developer holder.

15 . The image forming device according to claim 5 ,
wherein, in a case where the area coverage is higher than a predetermined threshold value, the controller applies, to the opposite electrode, a potential having the same polarity as the regular polarity and the same magnitude as that of the developer holder.

16 . The image forming device according to claim 6 ,
further comprising a first scraping member that comes into contact with the opposite electrode in a region of the opposite electrode at the opposite side to a region opposing the developer holder, and scrapes off the toner that has adhered to the opposite electrode from the opposite electrode, wherein the controller causes the opposite electrode to rotate in the same direction as the developer holder.

17 . The image forming device according to claim 11 ,
further comprising a first scraping member that comes into contact with the opposite electrode in a region of the opposite electrode at the opposite side to a region opposing the developer holder, and scrapes off the toner that has adhered to the opposite electrode from the opposite electrode, wherein the controller causes the opposite electrode to rotate in the same direction as the developer holder.

18 . The image forming device according to claim 11 ,
further comprising a second scraping member that comes into contact with the opposite electrode in a region of the opposite electrode that opposes the developer holder, and scrapes off the toner that has adhered to the opposite electrode from the opposite electrode, wherein the controller causes the opposite electrode to rotate in the opposite direction to the developer holder.

19 . The image forming device according to claim 16 ,
wherein an air passage is present below the first scraping member, and the toner that has been scraped off by the scraping member is sucked together with air through the air passage and is recovered.

20 . The image forming device according to claim 17 ,
wherein an air passage is present below the first scraping member, and the toner that has been scraped off by the scraping member is sucked together with air through the air passage and is recovered.

Assignees

• Fuji Xerox Co Ltd

Inventors

• Kanno Makoto
• Hamachi Tomoyuki
• Fukuno Ryo

Classifications

• G03G15/065 Primary

  Arrangements for controlling the potential of the developing electrode · CPC title