Image forming apparatus that regulates developing agent and applies regulatory bias

Patent metadata

Field	Value
Publication number	US-10852660-B2
Application number	US-201916676585-A
Country	US
Kind code	B2
Filing date	Nov 7, 2019
Priority date	Nov 14, 2018
Publication date	Dec 1, 2020
Grant date	Dec 1, 2020

Abstract

An image forming apparatus includes a regulating member that regulates a developing agent that a developing agent carrying member carries in order to develop an electrostatic image, and a regulatory bias application portion that applies a regulatory bias to the regulating member, wherein the developing agent includes a toner containing a toner particle, inorganic silicon fine particles present on the surface of the toner particle, and a metal soap, wherein the amount of water-washing migration of the inorganic silicon fine particles is 0.20 mass % or less, wherein a peripheral speed ratio, which is a ratio of a peripheral speed of the developing agent carrying member to a peripheral speed of an image bearing member, has a range of 120% to 300%, and a dark portion potential Vd on the surface of the image bearing member and a regulatory bias Vb satisfy the relationship of Vd<Vb.

First claim

What is claimed is:

1. An image forming apparatus comprising:
an image bearing member;
a latent image forming portion that forms a light portion potential and a dark portion potential on a surface of the image bearing member and thus forms an electrostatic image on the image bearing member;
a storage chamber storing a developing agent;
a developing agent carrying member that comes in contact with the image bearing member and develops the electrostatic image formed on the image bearing member using the developing agent;
a regulating member that regulates the developing agent that the developing agent carrying member carries to develop the electrostatic image; and
a regulatory bias application portion that applies a regulatory bias Vb to the regulating member,
wherein the developing agent in the storage chamber includes a toner containing a toner particle, inorganic silicon fine particles present on a surface of the toner particle, and a metal soap,
wherein the amount of water-washing migration of the inorganic silicon fine particles is 0.20 mass % or less,
wherein a peripheral speed ratio of a peripheral speed of the developing agent carrying member to a peripheral speed of the image bearing member has a range of 120% to 300%, and
wherein a dark portion potential Vd on the surface of the image bearing member and the regulatory bias satisfy the relationship of Vd<Vb.

2. An image forming apparatus comprising:
an image bearing member;
a latent image forming portion that forms a light portion potential and a dark portion potential on a surface of the image bearing member and thus forms an electrostatic image on the image bearing member;
a storage chamber storing a developing agent;
a developing agent carrying member that comes in contact with the image bearing member and develops the electrostatic image formed on the image bearing member using the developing agent;
a regulating member that regulates the developing agent that the developing agent carrying member carries to develop the electrostatic image; and
a regulatory bias application portion that applies a regulatory bias Vb to the regulating member,
wherein the developing agent in the storage chamber includes a toner containing a toner particle, organosilicon polymers covering the surface of the toner particle, and a metal soap,
wherein the amount of water-washing migration of the organosilicon polymers is 0.20 mass % or less,
wherein the Martens hardness of the toner measured in a condition of a maximum load of 2.0×10-4 N is at least 200 MPa and not more than 1,100 MPa,
wherein a peripheral speed ratio of a peripheral speed of the developing agent carrying member to a peripheral speed of the image bearing member, has a range of 120% to 300%, and
wherein a dark portion potential Vd on the surface of the image bearing member and the regulatory bias satisfy the relationship of Vd<Vb.

3. The image forming apparatus according to claim 1 , wherein a content of the metal soap in the toner is 0.20 mass % or more.

4. The image forming apparatus according to claim 1 , further comprising:
a supply member that comes in contact with the developing agent carrying member and supplies the developing agent to the developing agent carrying member,
wherein a movement direction on the surface of the supply member is opposite to a movement direction on the surface of the developing agent carrying member at a position in contact with the developing agent carrying member,
wherein a peripheral speed ratio, which is a ratio of a peripheral speed of the supply member to a peripheral speed of the developing agent carrying member, has a range of 70% to 150%, and
wherein the toner further contains a discharge product removal agent.

5. The image forming apparatus according to claim 4 , wherein a content of the discharge product removal agent in the toner is 0.20 mass % or more.

6. The image forming apparatus according to claim 4 , wherein the discharge product removal agent is an anion exchange compound.

7. The image forming apparatus according to claim 6 , wherein the anion exchange compound is a hydrotalcite compound.

8. The image forming apparatus according to claim 2 , wherein the organosilicon polymers have a partial structure represented by the following formula:
R—SiO 3/2 ,

where R represents a hydrocarbon group having at least 1 and not more than 6 carbon atoms.

9. The image forming apparatus according to claim 1 , wherein the image bearing member includes a protective layer on an outermost surface layer.

10. The image forming apparatus according to claim 9 , wherein the protective layer contains an acrylic resin.

11. The image forming apparatus according to claim 1 , wherein the metal soap contains at least one metal selected from the group consisting of zinc, calcium, and magnesium.

12. The image forming apparatus according to claim 1 , wherein the metal soap is zinc stearate, calcium stearate, or magnesium stearate.

13. The image forming apparatus according to claim 1 , wherein the average particle diameter of the metal soap is at least 0.15 μm and not more than 2.00 μm.

14. The image forming apparatus according to claim 1 , wherein the regulating member is made of stainless steel.

15. The image forming apparatus according to claim 1 , wherein the micro rubber hardness of the developing agent carrying member is 30 degrees to 50 degrees.

16. The image forming apparatus according to claim 1 , further comprising:
a developing bias application portion that applies a developing bias to the developing agent carrying member,
wherein the polarity of a potential difference between the developing bias and the regulatory bias is opposite to the polarity of the metal soap.

17. The image forming apparatus according to claim 1 , wherein the latent image forming portion includes:
a charging portion that charges the image bearing member to form the dark portion potential, the charging portion including a charging member that comes in contact with the image bearing member and a charging bias application portion that applies a charging bias to the charging member, and
an exposure portion that exposes the charged image bearing member and forms the light portion potential.

18. The image forming apparatus according to claim 1 , wherein the developing agent carrying member and a supply member that comes in contact with the developing agent carrying member rotate at a nip portion so that surfaces thereof move in an identical direction, and supplies a developing agent to the developing agent carrying member.

19. The image forming apparatus according to claim 18 , wherein, in an orientation during use, the developing agent carrying member and the supply member rotate so that surfaces thereof move in a direction from the top to the bottom at the nip portion.

20. The image forming apparatus according to claim 1 , wherein, in an orientation during use, a position at which the regulating member comes in contact with the developing agent carrying member is below a nip portion at which the developing agent carrying member comes in contact with a supply member that comes in contact with the developing agent carrying member and supplies a developing agent to the developing agent carrying member.

21. The image forming apparatus according to claim 1 , wherein, in an orientation during use, a position at which the regulating member comes in contact with the developing agent carrying member is below a rotation center of the developing agent carrying member a

Assignees

• Canon Kk

Inventors

• Ikada Kosuke
• Abe Katsuichi
• Hayashi Kodai
• Ikami Yasukazu
• Hagiwara Shinichi
• Kawasaki Shuhei

Classifications

• G03G15/0812

  characterised by the developer regulating means, e.g. structure of doctor blade · CPC title

• G03G15/08 Primary

  using a solid developer, e.g. powder developer · CPC title

• G03G15/065 Primary

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