Element Substrate Delay Circuit for Printhead Noise Reduction
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Solution Overview
Problem
Conventional full-line printheads with long wiring lengths experience electromagnetic noise and voltage drops due to large current flows, leading to uneven ink discharge and image density issues, as well as operation errors in logic circuits.
Innovation Solution
The implementation of a delay circuit on the element substrate that adjusts the timing of driving pulses to heaters, reducing current surges and minimizing electromagnetic noise, while ensuring stable voltage application and preventing operation errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of heaters to be concurrently driven is increased to improve printing speed, then productivity is improved, but voltage drop increases due to wiring resistance
Solution Approach 1:
The patent divides the heater array into multiple blocks (first block and second block) that can be driven independently. This segmentation allows different blocks to be activated simultaneously without causing excessive current concentration in single wiring paths, thereby maintaining voltage stability while improving overall printing speed through parallel operation of multiple blocks.
2Productivity
If large currents are supplied to drive multiple heaters concurrently to improve printing speed, then productivity is improved, but electromagnetic noise increases causing operation errors
Solution Approach 1:
By segmenting the heater array into multiple blocks with independent driving circuits, the patent distributes the current load across separate wiring paths. This reduces inductive coupling between adjacent high-current wires, thereby suppressing electromagnetic noise generation while maintaining high printing speed through concurrent operation of multiple blocks.
Solution Approach 2:
The patent introduces separate driving circuits as intermediary components between the power source and heater blocks. These driving circuits are designed with appropriate wiring layouts that minimize inductive coupling, acting as mediators that deliver required current to multiple blocks simultaneously while controlling electromagnetic noise through optimized circuit design.
3Reliability
If time-divisional driving is implemented to reduce voltage drop and electromagnetic noise, then reliability is improved, but printing speed decreases
Solution Approach 1:
The patent segments the heater array into multiple independently controllable blocks, enabling parallel driving of multiple blocks simultaneously. This eliminates the need for sequential time-divisional driving while maintaining voltage stability and reducing electromagnetic noise through the segmented architecture, thereby achieving both high reliability and high printing speed.
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 suppresses electromagnetic noise, prevents operation errors, and achieves high-quality image printing by ensuring consistent ink discharge and stable voltage across all heaters, thereby reducing density unevenness in printed images.
Implementation Method 1
At the leading and trailing edges of the large current supply, electromagnetic noise is generated by inductive coupling in the driving power wirings and the ground wirings.
Implementation Method 2
a plurality of heater arrays are arranged on an element substrate for a printhead
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
An element substrate (103) is provided. The element substrate comprises a plurality of printing elements (302) configured to generate energy to be used to discharge liquid, a first delay buffer group (401) formed by series-connecting a plurality of buffer circuits (403) in which a heat enable signal to be used to drive the printing element is transferred while being delayed by the plurality of buffer circuits, a second delay buffer group (402) formed by series-connecting a plurality of buffer circuits (403) in which the heat enable signal is transferred while being delayed by the plurality of buffer circuits in a direction different from an arrayed direction of the plurality of buffer circuits of the first delay buffer group, and a switchover circuit (404) configured to switch over, in accordance with a control signal, a delay sequence in a case where using the heat enable signal to drive each of the plurality of printing elements by switching over between the first delay buffer group and the second delay buffer group.