Fixing Heater Block Control for Variable Sheet Size Printing
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Solution Overview
Problem
Existing image forming apparatuses face challenges in efficiently heating toner images on sheets of varying sizes, particularly during continuous printing, due to incorrect sheet size information or positional shifts, leading to potential overheating of heater blocks.
Innovation Solution
The apparatus includes a control device that adjusts power supply to heater blocks based on sheet size detection, using main and sub-heater blocks, and implements feedback control and thermal protectors to prevent overheating, along with conveying interval control to manage sheet positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If power is supplied to all heater blocks regardless of sheet size, then heating coverage is maximized, but energy consumption increases and overheating risk occurs
Solution Approach 1:
The heater is divided into multiple heater blocks corresponding to different sheet size regions. The control device selectively supplies power to specific heater blocks based on the detected sheet size, enabling localized heating rather than uniform heating across the entire heater surface. This segmentation allows energy-efficient operation by activating only the necessary heating zones.
Solution Approach 2:
Different regions of the heater are assigned different heating functions based on sheet size. The control device adjusts which heater blocks are active according to the actual sheet dimensions, providing appropriate heating coverage only where needed. This local quality approach prevents energy waste in regions where no sheet is present.
2Productivity
If heater blocks operate continuously without monitoring, then heating efficiency is maintained, but temperature control precision deteriorates
Solution Approach 1:
The system incorporates sheet detection that provides feedback to the control device about the actual sheet presence and position. Based on this feedback, the control device dynamically adjusts which heater blocks receive power, ensuring precise temperature control matched to the actual heating requirements. This closed-loop control prevents both overheating and underheating.
3Speed
If sheet size information is not verified, then processing speed is maintained, but heating accuracy deteriorates
Solution Approach 1:
The sheet detection portion verifies sheet size and position before the heating process begins. The control device uses this preliminary verification information to pre-configured which heater blocks should be activated, ensuring heating accuracy is maintained without delaying the overall processing speed. This advance checking prevents heating errors while maintaining efficient operation.
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 ensures consistent and efficient heating of toner images on sheets of different sizes, preventing excessive temperature rise in heater blocks and maintaining printing quality during continuous operations.
Implementation Method 1
The heater includes a main heater block arranged in a reference area corresponding to the sheet having a reference size in a main direction crossing the sheet conveying direction, and a sub-heater block arranged in an outer-side area adjacent to the reference area in the main direction and corresponding to the sheet having a size larger than the reference size
Data Source
AI summary
A heater has a main heater block arranged in a reference area corresponding to a sheet having a reference size and a sub-heater block arranged in an outer-side area. An outer-side sheet sensor detects the sheet at a location within the outer-side area between a transfer device and a fixing device. The control device, depending on target size information representing a size of a target sheet, controls a power supply state between a first power supply state and a second power supply state. The control device, in a case in which the target size information represents a size exceeding the reference size, and depending on whether or not the outer-side sheet sensor detects the target sheet, further controls a conveying interval between the target sheet and a next sheet following the target sheet to one of a first interval and a second interval longer than the first interval.