Duplex Printing Show-Through Detection Using Reverse Transport
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Solution Overview
Problem
Existing image forming apparatuses struggle to detect show-through effectively during duplex printing, leading to reduced image quality and increased waste due to late detection of show-through.
Innovation Solution
The proposed image forming apparatus includes a show-through reading device positioned upstream of the image forming device, a reverse transport device to reverse the sheet faces, and a control device that detects show-through based on readings from the show-through reading device, allowing for early detection and appropriate action.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the reading device is positioned downstream of the image forming device to detect show-through, then the show-through can be detected after printing is complete, but the detection is delayed and cannot prevent waste of toner/ink and reduce productivity
Solution Approach 1:
The reading device is positioned upstream of the image forming device to perform show-through detection before the printing process is completed. This preliminary detection allows the system to identify show-through issues early, preventing waste of toner/ink and enabling timely corrective actions, thus resolving the contradiction between detection accuracy and detection timing.
2Device complexity
If the reading device is positioned downstream of the image forming device, then the detection process is simple, but the sheet cannot be repositioned for upstream reading and show-through detection is delayed
Solution Approach 1:
The sheet transport system incorporates dynamic control to reverse the sheet direction and transport it upstream to the reading device for show-through detection. This dynamic repositioning capability allows the system to achieve early detection without permanently complicating the device structure, thereby maintaining productivity while enabling timely show-through identification.
3Reliability
If show-through is detected late in the printing process, then the detection method is straightforward, but toner or ink is wasted and productivity is reduced
Solution Approach 1:
The system performs show-through detection before completing the printing process by positioning the reading device upstream and using the reverse transport mechanism to bring the sheet to the reading position early. This preliminary detection enables the system to identify show-through issues before toner/ink is wasted, directly addressing the contradiction between detection reliability and substance loss.
Data Source
AI summary
In an image forming apparatus, in a case of duplex printing, a sheet is transported toward an image forming device along a sheet transport route, the image forming device forms an image on a first face, which is one of faces of the sheet, a reverse transport device reverses the front and back faces of the sheet and transports the sheet to a position upstream of a show-through reading device in a sheet transport direction, and the show-through reading device reads a second face, which is another face of the sheet. Then the show-through detector decides whether a show-through has occurred, on a basis of the image that has been read.