Power supply device and image forming apparatus

By using a boost circuit and transistor base current control, a developing voltage higher than the surface potential of the photosensitive drum is generated, solving the problem of toner adhesion in the early stages of photosensitive drum rotation, thus improving image quality and simplifying the circuit.

CN115498876BActive Publication Date: 2026-06-09CANON KK
View PDF 3 Cites 0 Cited by

Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
CANON KK
Filing Date
2022-06-17
Publication Date
2026-06-09

AI Technical Summary

Technical Problem

Before the photosensitive drum rotates to the developing roller, toner may inadvertently adhere to the photosensitive drum, causing image defects. Existing technologies have not been able to effectively solve this problem.

Method used

A boost circuit is used to generate a developing voltage higher than the surface potential of the photosensitive drum. The output voltage is adjusted by controlling the base current of the transistor to ensure that toner adhesion is prevented in the early stage of the photosensitive drum rotation, and the voltage polarity is switched during the image formation period to achieve effective development.

Benefits of technology

It effectively prevents toner adhesion during the initial rotation of the photosensitive drum, reduces image defects, ensures image quality, and uses low-voltage transistors, reducing circuit design complexity and cost.

✦ Generated by Eureka AI based on patent content.

Smart Images

  • Figure CN115498876B_ABST
    Figure CN115498876B_ABST
Patent Text Reader

Abstract

A power supply device and an image forming apparatus are disclosed. The power supply device generates an output voltage. A boost-up section boosts a voltage supplied from a reference voltage source and generates a first power supply voltage. A processing section controls turning on and off of the boost-up section. A first transistor is connected to the first power supply voltage. A second transistor is connected to a collector of the first transistor. A resistive element is connected to a collector of the second transistor. A voltage source is connected to the resistive element and generates a second power supply voltage. A collector voltage of the second transistor as the output voltage is controlled by controlling an amount of a base current of the first transistor.
Need to check novelty before this filing date? Find Prior Art