Print Head Light Emission Control Circuit Phase Shift
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Solution Overview
Problem
Print heads with multiple light emitting elements face challenges in managing inrush current when simultaneously turning on or off, leading to increased load on the drive circuit, which can shorten the life of the light emitting elements and affect image quality.
Innovation Solution
The implementation of light emitting element arrays with a light emission control circuit that outputs drive signals of different phases to drive circuits, allowing individual control of light emitting elements in units of groups, thereby reducing current fluctuations and optimizing light emission timing to minimize current density and extend element life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If light emitting elements are simultaneously turned on or off to print a linear image, then image formation is achieved, but inrush current to the drive circuit increases
Solution Approach 1:
The patent divides the light emitting elements into multiple groups (first light emitting element group, second light emitting element group, etc.) and controls them with different phase shifts. This segmentation allows the groups to be turned on and off at different times, preventing simultaneous current changes and reducing inrush current to the drive circuit while maintaining efficient image formation.
2Ease of operation
If light emitting elements are simultaneously turned on or off, then control simplicity is maintained, but load on the drive circuit increases
Solution Approach 1:
The patent implements periodic control by shifting the phase of drive signals between different light emitting element groups. The first group is driven with a reference phase, while the second group is driven with a shifted phase, creating a periodic switching pattern that distributes the load over time. This reduces the peak load on the drive circuit while maintaining systematic control through regular phase relationships.
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 solution effectively reduces the load on the drive circuit and extends the life of light emitting elements by managing current fluctuations, while maintaining image quality and increasing light quantity without increasing current density.
Implementation Method 1
The print head includes a plurality of light emitting elements. As the light emitting elements, there are ones using a light emitting diode (LED)
Implementation Method 2
As the light emitting elements, there are ones using a light emitting diode (LED) and ones using an organic light emitting diode (OLED)
Implementation Method 3
The printer exposes a photoreceptor drum with light emitted from the light emitting elements, and prints an image, which corresponds to a latent image formed on the photoreceptor drum
Data Source
AI summary
According to an embodiment, a print head includes one or more light emitting element arrays, a light emission control circuit, and one or more drive circuit arrays. The light emitting element arrays include a plurality of light emitting elements arrayed continuously along a main scanning direction. The light emission control circuit outputs drive signals of different phases in units of a light emitting element group configured by a predetermined number of continuous light emitting elements included in the light emitting elements. The drive circuit arrays include a plurality of drive circuits, the drive circuits cause the light emitting elements to emit light individually based on the drive signals.