Inkjet Head Discharge Position Adjustor for Skew Correction
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Solution Overview
Problem
In image forming apparatuses using the inkjet method, edge sensors disposed upstream of the head units cannot directly detect the edge position at the head units, leading to lateral offset errors due to sheet skew or wobble, which affects the accurate adjustment of discharge positions for forming full-color images.
Innovation Solution
An edge detector unit and discharge position adjustor system that includes a controller to adjust the discharge position of recording devices by converting the detected edge position of the recording medium to the position of the recording device, using edge sensors both upstream and downstream of the head units to calculate and correct for skew and wobble-induced positional errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If edge sensors are disposed upstream of the head units, then the structure is simple and easy to manufacture, but the discharge position accuracy deteriorates due to lateral offset errors from sheet skew or wobble
Solution Approach 1:
The patent introduces an intermediary calculation process that converts edge positions detected at the sensor location to the head unit location using skew angle information. This mediator (conversion calculation) bridges the gap between the simple upstream sensor placement and the accurate discharge position requirement, allowing the system to maintain both ease of manufacture and manufacturing precision
Solution Approach 2:
The system uses feedback from edge sensors to detect sheet skew, calculates the skew angle, and uses this information to correct discharge positions. The feedback loop continuously monitors edge positions and adjusts discharge positions accordingly, maintaining accuracy despite the simplified upstream sensor placement
2Device complexity
If edge sensors are disposed upstream of the head units, then the device complexity is reduced, but the measurement precision of edge position at the head unit deteriorates
Solution Approach 1:
The patent uses skew angle calculation as an intermediary to translate edge position measurements from the upstream sensor location to the head unit location. This intermediary calculation preserves measurement precision without requiring physical sensors at the head unit, thus maintaining low device complexity
Solution Approach 2:
The patent replaces the mechanical solution of placing physical sensors at each head unit with a computational approach using skew angle calculations. This substitution maintains measurement precision while significantly reducing device complexity by eliminating additional hardware
Data Source
AI summary
A recording device discharge position adjustor includes a recording device to discharge liquid droplets onto a recording medium; an edge detector unit to detect a lateral edge position of the recording medium in a direction perpendicular to a recording medium conveyance direction; a discharge position adjustor to adjust a discharge position of the liquid droplets from the recording device relative to the recording medium; a controller to adjust the discharge position using the discharge position adjustor; and an edge position converter to convert the edge position of the recording medium detected by the edge detector unit to an edge position at a position of the recording device, in which the controller adjusts the discharge position of the recording device by an adjustment amount corresponding to the edge position of the recording medium at the position of the recording device converted by the edge position converter.