Image Forming Device Developing Bias Timing Control
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Solution Overview
Problem
Electrophotographic image forming devices face challenges in preventing carrier adhesion to the image carrying body while minimizing toner consumption, as the prevention of carrier adhesion often leads to increased toner consumption due to the trade-off in potential difference control between the developer carrying body and the image carrying body.
Innovation Solution
An image forming device with a control method that adjusts the timing of applying developing bias voltage relative to charging bias voltage based on the absolute value of the charging bias voltage, ensuring that larger absolute values result in shorter intervals and smaller absolute values result in longer intervals, thereby optimizing the potential difference to prevent carrier adhesion while reducing toner consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the potential difference between the developer carrying body and the image carrying body is controlled to prevent carrier adhesion, then carrier adhesion is prevented, but toner consumption increases
Solution Approach 1:
The patent applies dynamics by making the timing of developing bias voltage application variable rather than fixed. The control unit adjusts the timing based on detected carrier adhesion states, creating a dynamic system that adapts to different operating conditions. This resolves the contradiction by allowing the system to maintain carrier adhesion prevention only when necessary, rather than continuously applying the potential difference control that causes toner consumption.
Solution Approach 2:
The patent changes the timing parameter of developing bias voltage application based on detected conditions. By detecting carrier adhesion states and adjusting the timing parameter accordingly, the system optimizes the balance between preventing carrier adhesion and minimizing toner consumption. This parameter adjustment allows the system to prevent carrier adhesion only when the detection indicates it is needed.
2Reliability
If timing to start applying developing bias voltage is set early to prevent carrier adhesion, then carrier adhesion is prevented, but toner consumption increases
Solution Approach 1:
The patent implements feedback by detecting the carrier adhesion state and using this information to adjust the timing of developing bias voltage application. The detection unit monitors carrier adhesion, and the control unit responds by adjusting the timing parameter. This feedback mechanism allows the system to prevent carrier adhesion only when the detection indicates it is needed, rather than continuously applying early timing control, thus reducing unnecessary time loss.
3Productivity
If a foamed sponge transfer roller with uneven surface is used, then transfer performance is improved, but toner adhesion to the transfer roller increases
Solution Approach 1:
The patent applies preliminary action by controlling the timing of developing bias voltage application before the transfer process. By adjusting the timing parameter based on detected carrier adhesion states, the system prepares the developer carrying body in advance to prevent both carrier and toner adhesion to the transfer roller. This preliminary control prevents toner from adhering to the transfer roller's recessed portions before transfer, thus eliminating the harmful effect while maintaining transfer performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively prevents carrier adhesion while minimizing toner consumption across various charging conditions, ensuring reliable image formation without increasing manufacturing costs through complex hardware structures.
Implementation Method 1
a charging member, and a charging unit configured to apply charging bias voltage to the charging member and charge a surface of the image carrying body
Implementation Method 2
an exposure unit configured to expose the surface of the image carrying body charged by the charging unit to attenuate potential, and form an electrostatic latent image on the image carrying body
Implementation Method 3
a developing unit of a two-component development system configured to apply, to a developer carrying body, developing bias voltage having homopolarity with polarity of the charging bias voltage, and develop the electrostatic latent image
Data Source
AI summary
An image forming device includes: a charging unit configured to apply charging bias voltage to a charging member and charge a surface of an image carrying body; an exposure unit configured to expose the surface of the image carrying body, and form an electrostatic latent image; a developing unit configured to apply developing bias voltage to a developer carrying body, and develop the electrostatic latent image; and a control unit configured to control timing to start applying the developing bias voltage relative to timing to start applying the charging bias voltage, wherein the control unit performs control such that the larger an absolute value of the charging bias voltage is, the shorter an interval from timing to start applying the charging bias voltage to timing to start applying the developing bias voltage becomes, and such that the smaller the absolute value is, the longer the interval becomes.