Dynamic Roller Speed Control for Double-Face Printing
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Solution Overview
Problem
Conventional inkjet printing apparatuses require a longer time for double-face printing due to inefficiencies in the standby periods and ink distribution, which can lead to sheet jam and undesirable contact with the recording head.
Innovation Solution
A printing apparatus with a sheet conveyer unit and a controller that manages a first-face printing process, switchback process, and ink amount determination to adjust the rotation speed of rollers for efficient double-face printing, allowing for faster completion of the second-face printing by optimizing ink distribution and reducing sheet jam risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the sheet is conveyed at a constant high speed for switchback, then the productivity is improved, but the sheet may experience troubles such as sheet jam and undesirable contact with the recording head when ink is applied to the end area
Solution Approach 1:
The rotation speed of the first roller unit is dynamically adjusted based on the ink distribution pattern. When ink is applied to the end area, the roller speed is reduced to prevent sheet troubles; when ink is applied to the central area, the roller speed is increased to shorten processing time. This dynamic speed adjustment resolves the contradiction between productivity and reliability.
Solution Approach 2:
The patent changes the operational parameter (roller rotation speed) based on the ink distribution pattern detected on the sheet. By monitoring where ink is applied and adjusting the switchback speed accordingly, the system optimizes both printing efficiency and sheet handling reliability, preventing sheet jams and undesirable contacts.
2Productivity
If the standby period between first-face and second-face printing is shortened, then the productivity is improved, but the risk of sheet troubles increases when ink is applied to the end area
Solution Approach 1:
The standby period is optimized by changing the roller rotation speed parameter based on ink distribution. When ink is in the central area, faster switchback reduces standby time. When ink is in the end area, slower switchback prevents sheet troubles. This parameter adaptation resolves the contradiction between productivity and harmful factors.
Solution Approach 2:
The patent applies different roller speed settings for different ink distribution scenarios. The switchback speed is locally optimized according to the specific ink pattern on the sheet, allowing aggressive timing when safe and conservative timing when needed, thus resolving the contradiction between short standby periods and sheet safety.
3Productivity
If the roller rotation speed is increased to reduce processing time, then the productivity is improved, but the sheet may experience troubles when ink is applied to the end area
Solution Approach 1:
The roller rotation speed is made dynamic rather than constant. The controller adjusts the speed in real-time based on ink distribution detection. High speed is used when ink is in the central area for productivity, while low speed is used when ink is in the end area for reliability, resolving the contradiction between processing time and sheet safety.
Solution Approach 2:
The system uses feedback from ink distribution detection to control roller speed. The controller receives information about where ink is applied and adjusts the switchback speed accordingly. This feedback mechanism allows the system to automatically optimize the balance between productivity and reliability based on actual sheet conditions.
Data Source
AI summary
A printing apparatus, including a sheet conveyer unit with a first roller unit, a printer unit, and a controller, is provided. The controller executes a first-face printing process, wherein an image is printed on a first face of a sheet; a switchback process, wherein the sheet after the first-face printing process is conveyed in a reverse direction by the first roller unit; a second-face printing process, wherein the image is printed on a second face of the sheet; a first ink amount determining process to determine whether an ink amount discharged in the first-face printing process at an end area of the sheet is one of greater than and equal to a first threshold amount; and a switchback setting process, wherein, if the ink amount is smaller than the first threshold amount, a rotation speed of the first roller unit is set at a higher rotation speed.