LPH Controller Sync Signal Adjustment for OPC AC Compensation

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Solution Overview

Problem

Conventional image forming apparatuses using LED Print Heads (LPH) face challenges in adjusting line sync signals without increasing motor speed, leading to higher manufacturing costs and reduced productivity due to the need for multiple data lines and increased data clock frequencies, which limits high-speed, high-resolution printing.

Innovation Solution

The apparatus adjusts line sync signals per color to compensate for AC errors by generating and transmitting sync reference signals, allowing for OPC AC compensation without motor speed control, using a video interface to transmit print data, and maintaining the same data clock frequency, thus eliminating the need for additional parallel interfaces and reducing data line expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If motor speed control is used for OPC AC compensation, then AC component elimination is improved, but device complexity and manufacturing cost increase due to requiring separate motors for each OPC

Engineering Contradiction:
ImproveAC component eliminationVSAvoidmotor control system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical motor speed control system with an electronic line sync signal adjustment system. Instead of controlling motor speed to compensate for AC components, the invention adjusts the timing and synchronization of line sync signals electronically, thereby eliminating the need for separate motors for each OPC while achieving the same AC compensation effect

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent makes a single motor serve multiple OPCs simultaneously by using a unified motor control system that drives all OPCs in tandem. This eliminates the need for separate motors for each OPC, reducing device complexity while maintaining the ability to perform AC compensation through line sync signal adjustment

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Device complexity

If LPH controller is integrated into main controller, then device complexity is reduced, but data transmission speed and resolution are limited due to cable length constraints

Engineering Contradiction:
Improvecontroller configurationVSAvoiddata transmission speed
Core Design Contradiction:
Device complexityVSSpeed

Solution Approach 1:

The patent divides the control system into separate LPH controller and main controller units, allowing the LPH controller to be positioned close to the LPH module. This segmentation enables high-speed data transmission through short local connections while keeping the overall system architecture flexible and manageable

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a parallel interface as an intermediary communication channel between the main controller and LPH controller. This parallel interface enables high-speed data transmission without being constrained by cable length limitations of serial connections, effectively bridging the two controllers while maintaining high transmission speeds

Inventive Principle:
Principle #24Intermediary (Mediator)

3Quantity of substance

If data line width is increased for multi-bit transmission, then data transmission capability is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvedata transmission capabilityVSAvoiddata line configuration
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent uses time-division multiplexing to transmit multi-bit data sequentially over a single data line. Instead of requiring multiple parallel data lines for simultaneous multi-bit transmission, the system transmits data bits in periodic time slots, achieving the same data transmission capability with a single line and reducing device complexity

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent transitions from spatial multiplexing (multiple parallel data lines) to temporal multiplexing (single data line with time-division). By adding the time dimension to data transmission, the system achieves multi-bit transmission capability without increasing the number of physical data lines, thereby reducing device complexity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3112941B1Image forming apparatus, controlling method of thereof and non-transitory computer readable storage medium
Publication Date: 2018.09.05 HP PRINTING KOREA CO LTD
  • EP3112941B1 patent drawingFigure 1~2
  • EP3112941B1 patent drawingFigure 3~4
  • EP3112941B1 patent drawingFigure 5

AI summary

An image forming apparatus includes an image former configured to perform printing using an LPH (LED Print Head) that emits light to a photosensitive drum based on a sync signal; a sensor configured to sense a cyclical speed of the photosensitive drum; and an LPH controller configured to adjust a generation gap of the sync signal using the sensed cyclical speed.