On-Chip Fire Pulse Generator for Inkjet Printhead
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Solution Overview
Problem
Inkjet printing systems face issues with intermittent connections to the printer controller, high costs due to flex interconnects, and ink ingress causing shorts between signals, particularly in multi-column printheads.
Innovation Solution
The implementation of an on-chip fire pulse generator within the printhead, which uses precursor pulses to generate multiple fire pulses internally, reducing the need for external connections and eliminating the requirement for extra pads, thereby enhancing reliability and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple connections are made between printhead and controller, then timing control precision is improved, but system reliability deteriorates due to intermittent connections and ink ingress
Solution Approach 1:
The fire pulse generator is extracted from the external controller and integrated directly into the printhead circuitry. This removes the need for multiple external connections while maintaining precise timing control, as the generator is now locally housed within the printhead assembly itself
Solution Approach 2:
The on-chip fire pulse generator acts as an intermediary between the controller and the nozzle firing mechanism. It receives a single start signal from the controller and autonomously generates the precise multi-phase fire pulse sequence needed for multi-column operation, eliminating the need for multiple external timing connections
2Ease of operation
If multiple connections are made between printhead and controller, then fire signal control is improved, but cost increases due to higher flex interconnect cost
Solution Approach 1:
The fire pulse generation capability is extracted from the external controller and embedded directly into the printhead. This eliminates the need for expensive multi-connection flex interconnects while maintaining full fire signal control capability through local pulse generation
Solution Approach 2:
The on-chip fire pulse generator provides multiple functions within a single integrated component: it generates precursor pulses, main fire pulses, and intermediate timing signals for multiple columns simultaneously, replacing what would otherwise require multiple separate external control connections
3Adaptability or versatility
If multiple connections are made between printhead and controller, then signal control capability is improved, but risk of ink ingress causing shorts increases
Solution Approach 1:
The fire pulse generator is extracted from the external controller environment and relocated into the sealed printhead housing. This minimizes the number of electrical connections that penetrate the printhead seal, thereby reducing the pathways through which ink could ingress and cause shorts while maintaining full signal control capability
Solution Approach 2:
The printhead becomes self-sufficient in generating its own fire pulses through the on-chip generator. It no longer requires multiple external control connections for timing and sequencing, as the generator autonomously creates the complete fire signal sequence internally based on a single start trigger
4Reliability
If on-chip fire pulse generator is implemented, then number of connections is reduced, but pulse generation complexity increases
Solution Approach 1:
The pulse generation process is segmented into distinct functional stages: a start trigger phase, a precursor pulse phase with specific timing, a main fire pulse phase, and an intermediate timing phase. Each stage is handled by dedicated circuit blocks within the on-chip generator, managing complexity through functional segmentation while maintaining reliability through reduced external connections
Data Source
AI summary
An ink cartridge comprises an inkjet printhead assembly and an ink supply assembly, the inkjet printhead assembly comprising an integrated fire pulse generator and a printhead having at least one nozzle opening (416) having associated therewith a firing resistor (408). The integrated fire pulse generator comprises a precursor end register (520) to initiate at least one precursor pulse, a dead time end register (530) to initiate at least one predetermined time period pause, and a fire end register (540) to initiate at least one firing pulse after the pause. A controller (510) sends the at least one precursor pulse to the firing resistor, removes the at least one precursor pulse from the firing resistor for the predetermined pause, and sends the at least one firing pulse to the firing resistor for ejecting an ink drop.