Image Forming Apparatus Conveying Speed Control for Small Sheets
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Solution Overview
Problem
Existing electrophotographic image forming apparatuses face reduced throughput and shortened apparatus life when handling small size sheets, as they often require increased sheet intervals to prevent non-sheet-passage-part temperature rises, leading to low productivity and prolonged First Print Out Time due to fixed image forming speeds based on recording material widths.
Innovation Solution
An image forming apparatus with a control portion that adjusts conveying speed based on the number of small size sheets stored in a history database, switching between two speeds depending on the number of sheets to optimize throughput and prevent temperature rises, allowing for flexible operation regardless of sheet size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the throughput is reduced by increasing the sheet feeding interval to prevent non-sheet-passage-part temperature rise, then the temperature control is improved, but the productivity deteriorates
Solution Approach 1:
The patent applies dynamics by making the image forming speed variable rather than fixed. The control portion dynamically adjusts the image forming speed based on the number of sheets printed in the same size group, switching between high speed (200 mm/sec) for small print volumes and low speed (100 mm/sec) for large print volumes. This dynamic adjustment resolves the contradiction by allowing high throughput when temperature rise is not an issue while preventing temperature rise when print volume is high.
2Temperature
If the image forming speed is lowered to prevent non-sheet-passage-part temperature rise, then the temperature control is improved, but the productivity deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the image forming speed parameter based on print volume conditions. The control portion changes the speed parameter from 200 mm/sec to 100 mm/sec when the number of sheets to be printed reaches or exceeds a predetermined threshold. This parameter adjustment allows the system to maintain temperature control while optimizing throughput based on actual printing conditions.
3Temperature
If the sheet interval is increased to reduce throughput and prevent temperature rise, then the temperature control is improved, but the apparatus life deteriorates due to prolonged cartridge rotation
Solution Approach 1:
The patent applies dynamics by dynamically adjusting the image forming speed based on real-time print volume conditions. When print volume is small, the system operates at high speed with normal sheet intervals, reducing cartridge idle rotation time. When print volume is large, the system switches to low speed to prevent temperature rise. This dynamic control prevents both temperature issues and excessive cartridge rotation, thereby protecting apparatus life.
4Productivity
If the throughput is enhanced by increasing image forming speed, then the productivity is improved, but the non-sheet-passage-part temperature rise increases
Solution Approach 1:
The patent applies parameter changes by adjusting the image forming speed parameter according to print volume. The control portion monitors the number of sheets to be printed and changes the speed parameter from 100 mm/sec to 200 mm/sec when the print volume is small, allowing high throughput. When print volume is large, the parameter is set to 100 mm/sec to prevent temperature rise. This conditional parameter adjustment resolves the contradiction between throughput and temperature control.
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 enhances productivity and extends the life of the apparatus by dynamically adjusting conveying speeds according to the number of small size sheets, maintaining optimal throughput and reducing temperature-related issues, thereby improving overall printing efficiency and reducing component wear.
Implementation Method 1
a fixing portion including a nip portion that nips and conveys the recording material, the fixing portion heating the image at the nip portion to fix the image onto the recording material
Data Source
AI summary
An image forming apparatus, including: a control portion that controls a conveying speed of recording materials when the recording materials pass through a nip portion; wherein the control portion, in a case of continuous sheet passing of the recording materials each having a smaller width than the recording materials each having a maximum width: executes, in a case where a representative value of the number of the recording materials having the smaller width for one operation of the continuous sheet passing is smaller than a predetermined threshold, a first operating mode in which the conveying speed is controlled to a first speed; and executes, in a case where the representative value is the threshold or more, a second operating mode in which the conveying speed is controlled to a second speed lower than the first speed.