Sheet Guide Ventilation for Printer Cooling
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Solution Overview
Problem
Existing image forming apparatuses face issues with sheet conveyance failures due to insufficient cooling, particularly during high-speed printing and double-sided printing, where toner sticking occurs, and conventional cooling methods either cause sheet curling or require complex control systems.
Innovation Solution
An image forming apparatus with a sheet conveyance path, heat-treatment portion, conveyance rollers, and a cooling device, featuring ventilation portions in the sheet guides to direct cooling air effectively, preventing sheet curling and jamming while maintaining a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air is blown toward a sheet by a cooling fan to cool down the sheet, then the sheet can be cooled down, but sheet conveyance failure (curling up, bending, jam) may occur
Solution Approach 1:
A cooling air passage is introduced as an intermediary structure between the cooling fan and the sheet. The passage guides cooling air to flow along the downstream side of the sheet from the downstream end toward the upstream end, preventing direct air impact on the sheet while still achieving cooling. This mediator structure eliminates sheet conveyance failures caused by direct air blowing while maintaining effective heat dissipation.
2Temperature
If the cooling fan operates continuously to cool sheets, then cooling effectiveness is improved, but sheet conveyance failure may occur due to air flowing backwards
Solution Approach 1:
The cooling air passage is designed with a specific flow direction that preliminarily guides cooling air along the downstream side of the sheet before it reaches the sheet surface. The passage structure pre-establishes a controlled airflow path that prevents backward flow and air accumulation, eliminating the need for complex fan control while ensuring reliable sheet conveyance during continuous operation.
3Reliability
If the conveyance path length is extended to prevent sticking, then the sheet can be cooled down, but the device becomes larger in size
Solution Approach 1:
A cooling air passage is introduced to deliver cooling air directly to the sheet surface in the downstream region after the heat treatment portion. This pneumatic cooling method enables effective heat dissipation within a compact space, preventing toner sticking without requiring an extended conveyance path, thus maintaining a compact device size while achieving reliable cooling.
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
The apparatus effectively cools sheets post-fixing processing, preventing toner sticking and sheet conveyance failures, and simplifies cooling fan control by ensuring continuous operation without causing conveyance issues.
Implementation Method 1
a cooling device configured to cool down a sheet having been conveyed between the outer sheet guide and the inner sheet guides by cooling air
Implementation Method 2
a fixing device that fixes and fuses an unfixed toner image on a sheet by heat and pressure
Data Source
AI summary
An image forming apparatus capable of effectively cooling down a sheet having been subjected to fixing processing while preventing an apparatus from becoming larger in size and a sheet conveyance failure from occurring is provided. The image forming apparatus (10) includes a sheet conveyance path (16), a fixing device (22), a conveyance roller (26), an upper sheet guide (60), a lower sheet guide (62), and a cooling fan (40). The conveyance roller (26) is disposed downstream of a heat-treatment portion in the sheet conveyance path and configured so as to convey a sheet passing the heat-treatment portion to the paper output tray. At a position corresponding to the position of the conveyance rollers (26), the upper sheet guide (60) is provided with a ventilation portion (604) configured so as to make the cooling air from the cooling device (40) pass through. At a position opposed to the ventilation portion (604) of the upper sheet guide (60), the lower sheet guide (62) is provided with a ventilation portion (624) configured so as to make the cooling air from the cooling device (40) pass through.