Polyester Toner Ketone Impurity Control
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Solution Overview
Problem
Toner used in electrophotographic systems experiences staining issues in the machine, particularly with charging members like corotron or scorotron, due to the volatilization of impurities during temperature elevation, which affects low-temperature fixing ability and offset resistance.
Innovation Solution
A polyester toner is developed by polycondensing an alcohol component and a carboxylic acid component containing alkylsuccinic acid and alkenylsuccinic acid, with specific ketone components like 6-methyl-2-heptanone and 5-methyl-2-heptanone reduced to below 0.5 ppm using thermal desorption-gas chromatography-mass spectrometry, and water added to the reaction system to form an azeotrope, enhancing low-temperature fixing ability and offset resistance while minimizing machine staining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyester resin obtained by using an alkylsuccinic acid or an alkenylsuccinic acid, each having 10 or more carbon atoms, is used to improve low-temperature fixing ability and offset resistance, then the toner exhibits excellent low-temperature fixing ability and offset resistance, but the toner causes staining in the machine due to volatilization of impurities during temperature elevation
Solution Approach 1:
The patent changes the chemical composition parameters of the carboxylic acid component by specifying the type of alkylsuccinic acid or alkenylsuccinic acid used and controlling the content of specific ketone impurities (6-methyl-2-heptanone and 5-methyl-2-heptanone) to 0.5 ppm or less. This parameter control allows the polyester resin to maintain excellent low-temperature fixing ability and offset resistance while eliminating the machine staining problem caused by volatile impurities
Solution Approach 2:
The patent converts the harmful effect of volatile ketone impurities causing machine staining into a beneficial outcome by strictly controlling and minimizing their content to 0.5 ppm or less. This transformation allows the use of alkylsuccinic acid or alkenylsuccinic acid-based polyester resins that provide excellent low-temperature fixing ability and offset resistance without the harmful staining side effect
2Object-generated harmful factors
If the content of ketone components (6-methyl-2-heptanone and 5-methyl-2-heptanone) is reduced to 0.5 ppm or less to eliminate machine staining, then machine staining is reduced, but the production process becomes more complex requiring thermal desorption-gas chromatography-mass spectrometry for detection
Solution Approach 1:
The patent applies preliminary action by controlling the ketone component content during the polyester resin production process itself, rather than detecting and correcting it after production. By specifying the use of particular alkylsuccinic acid or alkenylsuccinic acid and controlling the ketone content to 0.5 ppm or less during manufacturing, the patent prevents machine staining from occurring in the first place, making advanced detection methods unnecessary for quality 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
The polyester toner exhibits improved low-temperature fixing ability, offset resistance, and reduced machine staining, maintaining excellent performance by minimizing volatile impurities and optimizing the polycondensation process.
Implementation Method 1
water is added to a reaction system at a temperature of from 100° to 300° C. during, after, or during and after the reaction of an alcohol component and an alkylsuccinic acid having 10 or more carbon atoms, an alkenylsuccinic acid having 10 or more carbon atoms, or a mixture thereof, in an amount of from 0.1 to 50 parts by weight, based on 100 parts by weight of the polyester obtained
Data Source
AI summary
The present invention relates to a polyester for a toner, obtained by polycondensing an alcohol component and a carboxylic acid component containing an alkylsuccinic acid having 10 or more carbon atoms, an alkenylsuccinic acid having 10 or more carbon atoms, or a mixture thereof, in an amount of from 0.5 to 50% by mole, wherein each of 6-methyl-2-heptanone and 5-methyl-2-heptanone is detected in an amount of 0.5 ppm or less as determined by thermal desorption-gas chromatography-mass spectrometry. The polyester for a toner of the present invention is used as a resin binder, or the like, for a toner used, for example, for developing electrostatic latent images formed in electrophotography, electrostatic recording method, electrostatic printing method, or the like.