Discharging method for latent image bearer and image forming apparatus

Patent metadata

Field	Value
Publication number	US-9971269-B2
Application number	US-201715590129-A
Country	US
Kind code	B2
Filing date	May 9, 2017
Priority date	May 23, 2016
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

A discharging method used in an image forming apparatus includes discharging, with an exposure device, an exposure range of the latent image bearer, and discharging, with a discharger, an area of the latent image bearer outside the exposure range and inside a developing range in a main scanning direction. The exposure range is inside the developing range in the main scanning direction. The discharging with the exposure device and the discharging with the discharger are performed when a rotation of the latent image bearer is stopped after a toner image is transferred from the latent image bearer.

First claim

What is claimed is:

1. A discharging method used in an image forming apparatus including a latent image bearer, an exposure device to expose the latent image bearer to form an electrostatic latent image on the latent image bearer, and a discharger different from the exposure device,
the discharging method comprising:
discharging, with the exposure device, an exposure range of the latent image bearer, the exposure range inside a developing range in a main scanning direction; and
discharging, with the discharger, an area of the latent image bearer outside the exposure range and inside the developing range in the main scanning direction,
wherein the discharging with the exposure device and the discharging with the discharger are performed when a rotation of the latent image bearer is stopped after a toner image is transferred from the latent image bearer.

2. The discharging method according to claim 1 , wherein the discharging with the discharger includes emitting exposure light from a light-emitting element to the latent image bearer.

3. The discharging method according to claim 2 , wherein an amount of light emitted from the discharger to exposure the latent image bearer is different from an amount of exposure light emitted from the exposure device to expose the latent image bearer.

4. The discharging method according to claim 2 , wherein a resolution of exposure of the discharger is different from a resolution of exposure of the exposure device.

5. The discharging method according to claim 1 , wherein a range discharged by the discharger and the exposure device in combination is equal to or longer than the developing range on the latent image bearer in the main scanning direction.

6. The discharging method according to claim 1 , wherein the discharging with the discharger includes emitting exposure light from a light-emitting element to the latent image bearer, and
the discharging method further comprises setting a relation defined by Formula 1,
L min≤ V·T≤L max  Formula 1

where Lmax represents a distance in millimeters between an upstream end of a discharge area by the discharger and a discharge area by the exposure device in a direction of rotation of the latent image bearer;
Lmin represents a distance in millimeters between a downstream end of the discharge area by the discharger and the discharge area by the exposure device in the direction of rotation of the latent image bearer;
V represents the rotation speed in millimeters per second of the latent image bearer; and
T represents a period in seconds from when the discharger starts the discharging to when the exposure device starts the discharging.

7. The discharging method according to claim 6 , further comprising performing an adjustment to satisfy Formula 2,
L min≤ V·Tb≤V·Ta≤L max  Formula 2,

where Ta represents a period in seconds from when the discharger starts the discharging to when the exposure device starts the discharging, in a state in which a usage history of the discharger is relatively short; and
Tb represents a period in seconds from when the discharger starts the discharging to when the exposure device starts the discharging, in a state in which the usage history of the discharger is relatively long.

8. The discharging method according to claim 6 , wherein the latent image bearer is rotated at one of a plurality of rotation speeds including a first speed and a second speed lower than the first speed, and
wherein the discharging method further comprises performing an adjustment to satisfy Formula 3,
L min≤ Vh·Th≤Vl·Tl≤L max  Formula 3

where Vh represents the first speed in millimeters per second;
Th represents a period in seconds from when the discharger starts the discharging to when the exposure device starts the discharging, while the latent image bearer is rotated at the first speed,
Vl represents the second speed in millimeters per second; and
Tl represents a period in seconds from when the discharger starts the discharging to when the exposure device starts the discharging, while the latent image bearer is rotated at the second speed.

9. An image forming apparatus comprising:
a latent image bearer to rotate;
a charger to charge the latent image bearer uniformly;
an exposure device to expose an exposure range of the latent image bearer to form an electrostatic latent image on the latent image bearer;
a developing device to develop, in a developing range, the electrostatic latent image with developer into a toner image, the developing range wider than the exposure range in a main scanning direction;
a transfer device to transfer the toner image from the image bearer onto a transfer medium; and
a discharger different from the exposure device, to discharge the latent image bearer,
wherein the exposure device and the discharger discharges the latent image bearer when rotation of the latent image bearer is stopped after the transfer device transfers the toner image,
wherein the exposure device discharges the exposure range inside the developing range in the main scanning direction, and
wherein the discharger discharges an area of the latent image bearer outside the exposure range and inside the developing range in the main scanning direction.

10. The image forming apparatus according to claim 9 , wherein the discharger includes a light-emitting element to expose the latent image bearer to discharge the latent image bearer.

11. The image forming apparatus according to claim 9 , wherein a distance from the latent image bearer to the discharger is greater from a distance from the latent image bearer to the exposure device.

Assignees

• Ohi Ryouhei
• Miyazaki Takafumi
• Meguro Yuuji
• Fujiwara Yasuhiro
• Ricoh Co Ltd

Inventors

• Ohi Ryouhei
• Miyazaki Takafumi
• Meguro Yuuji
• Fujiwara Yasuhiro

Classifications

• G03G2221/00

  Processes not provided for by group G03G2215/00, e.g. cleaning or residual charge elimination · CPC title

• G03G15/24

  whereby at least two steps are performed simultaneously · CPC title

• G03G15/0208

  by contact, friction or induction, e.g. liquid charging apparatus · CPC title

• G03G2215/02

  Arrangements for laying down a uniform charge · CPC title

• G03G15/0291

  corona discharge devices, e.g. wires, pointed electrodes, means for cleaning the corona discharge device · CPC title