# US 2019/0072876 A1 · Developing device

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- Number: US 2019/0072876 A1
- Document ID: US20190072876A1
- Status: Published application
- Kind: A1
- Application number: 16/122,633
- Filed: 2018-09-05
- Published: 2019-03-07
- Earliest claimed: 2017-09-07
- Assignees: Canon Kabushiki Kaisha
- Applicants: Canon Kabushiki Kaisha
- Inventors: Tomohiro Shiomi; Teruaki Tsurusaki; Shunichi Koga
- Web page: https://patentgrep.com/patent/US20190072876A1

## CPC

- G03G 15/0812: {characterised by the developer regulating means, e.g. structure of doctor blade}
- G03G 2215/0634: Developing device
- G03G 2215/1628: Blade
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

When the area of a developing frame member corresponding to the maximum image area of an image bearing member is, in a section perpendicular to a rotational axis of a developing rotary member, divided by a straight line passing through the center of rotation of the developing rotary member and the center of rotation of the image bearing member and a perpendicular line passing through the center of rotation of a first conveying screw with respect to the straight line, a gate portion is provided at a bottom portion of the developing frame member in a divided area of the developing frame member not provided with the attachment portion, and a gate portion is not provided at the bottom portion of the developing frame member in a divided area of the developing frame member provided with the attachment portion.

## Claims

### Claim 1

A developing device comprising:
a developing rotary member configured to carry and convey a developer comprising toner and a carrier toward a position at which an electrostatic image formed on an image bearing member is developed;
a resin regulating blade arranged facing the developing rotary member in a non-contact manner and configured to regulate an amount of the developer carried on the developing rotary member;
a developing frame member at least including a first chamber where the developer is supplied to the developing rotary member, a second chamber divided from the first chamber by a partition wall, and an attachment portion for attachment of the regulating blade, the attachment portion being provided in a maximum image area of an image area of the image bearing member where an image can be formed on the image bearing member in a rotational axis direction of the developing rotary member;
a first conveying screw arranged in the first chamber and configured to convey the developer of the first chamber in a first conveying direction; and
a second conveying screw arranged in the second chamber and configured to convey the developer of the second chamber in a second conveying direction as an opposite direction of the first conveying direction,
wherein the regulating blade is fixed to an area of the attachment portion corresponding to the maximum image area of the image bearing member in the rotational axis direction of the developing rotary member in a state that the regulating blade is deflected such that a gap between the developing rotary member supported on the developing frame member and the regulating blade attached to the attachment portion falls within a predetermined range across the rotational axis direction of the developing rotary member, and
when an area of the developing frame member corresponding to the maximum image area of the image bearing member is, in a section perpendicular to a rotational axis of the developing rotary member, divided by a straight line passing through a center of rotation of the developing rotary member and a center of rotation of the image bearing member and a perpendicular line passing through a center of rotation of the first conveying screw with respect to the straight line,
a gate portion is provided at a bottom portion of the developing frame member in a divided area of the developing frame member not provided with the attachment portion, and
a gate portion is not provided at the bottom portion of the developing frame member in a divided area of the developing frame member provided with the attachment portion.

### Claim 2 (depends on 1)

The developing device according to claim 1, wherein
a thickness size of the gate portion is greater than a basic thickness size of the developing frame member.

### Claim 3 (depends on 1)

The developing device according to claim 1, wherein
a basic thickness size of the developing frame member is equal to or greater than 1.0 mm and equal to or less than 3.0 mm.

### Claim 4 (depends on 1)

The developing device according to claim 1, wherein
the regulating blade is, with an adhesive, fixed across an entirety of the area of the attachment portion corresponding to the maximum image area of the image bearing member in the rotational axis direction of the developing rotary member in a state that the regulating blade is deflected such that the gap falls within the predetermined range across the rotational axis direction of the developing rotary member.