POWDER-AMOUNT DETECTION DEVICE AND IMAGE FORMING APPARATUS INCORPORATING SAME

• US 20180341199A1
• Filed: 05/21/2018
• Published: 11/29/2018
• Est. Priority Date: 05/24/2017
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: YAMASHITA, Masahide, KUMIYA, Taku, KUSHIDA, Yohei, MURATA, Takuya, MAEJIMA, Keita
• Granted Patent: US 10,599,064 B2
• Time in Patent Office: Days
• CPC Class Codes: G03G 15/086 the level being measured by electro-magnetic means
• CPC Class Codes: G03G 15/0865 Arrangements for supplying new developer
• CPC Class Codes: G03G 15/0867 cylindrical developer cartridges, e.g. toner bottles for the developer replenishing opening
• CPC Class Codes: G03G 15/556 for toner consumption, e.g. pixel counting, toner coverage detection or toner density measurement
• CPC Class Codes: G03G 2215/0888 Arrangements for detecting toner level or concentration in the developing device
• CPC Class Codes: G03G 2215/1623 Transfer belt
• CPC Class Codes: G03G 2215/1661 of transfer belt

Abstract

A powder-amount detection device includes a first electrode disposed on one side of a powder container to be replaceably installed to an image forming apparatus; a second electrode disposed adjacent to the first electrode and having a smaller surface area than the first electrode, an influence of an amount of powder in the powder container to a capacitance of the second electrode being as small as negligible; a third electrode disposed on a side opposite to the second electrode with the powder container interposed between the third electrode and each of the first electrode and the second electrode; and a voltage detector configured to detect charging and discharging behaviors of the first electrode and the second electrode when a voltage is applied between the third electrode and each of the first electrode and the second electrode for a short time, to detect the amount of powder in the powder container.

Claims

1. A powder-amount detection device comprising:

a first electrode disposed on one side of a powder container to be replaceably installed to an image forming apparatus;

a second electrode disposed adjacent to the first electrode and having a smaller surface area than a surface area of the first electrode, an influence of an amount of powder in the powder container to a capacitance of the second electrode being as small as negligible;

a third electrode disposed on a side opposite to the second electrode with the powder container interposed between the third electrode and each of the first electrode and the second electrode; and

a voltage detector configured to detect voltages of the first electrode and the second electrode,

the voltage detector configured to detect charging and discharging behaviors of the first electrode and the second electrode when a voltage is applied between the third electrode and each of the first electrode and the second electrode for a short time, to detect the amount of powder in the powder container.

2. The powder-amount detection device according to claim 1,

wherein the voltage detector detects a capacitance from a value obtained by subtracting a voltage obtained from the second electrode from a voltage obtained from the first electrode and detects the amount of powder in the powder container based on the capacitance detected.

3. The powder-amount detection device according to claim 1, further comprising:

a dielectric layer disposed on an outer side of the first electrode and the second electrode; and

a driving electrode disposed at an outer side of the dielectric layer with the dielectric layer interposed between the driving electrode and each of the first electrode and the second electrode,

wherein the voltage detector applies a voltage to the driving electrode for a short time to charge and discharge the first electrode and the second electrode.

4. The powder-amount detection device according to claim 3,

wherein the voltage applied to the driving electrode is an alternating current voltage.

5. The powder-amount detection device according to claim 1,

wherein the third electrode is a ground electrode earthed to ground.

6. The powder-amount detection device according to claim 1,

wherein the first electrode and the second electrode are disposed with a same length in a longitudinal direction of the powder container having a cylindrical shape.

7. The powder-amount detection device according to claim 1,

wherein the first electrode, the second electrode, and the third electrode are disposed in non-contact with the powder container.

8. An image forming apparatus comprising:

an image forming unit; and

the powder-amount detection device according to claim 1, disposed in the image forming unit.