TWO-COMPONENT DEVELOPER, REPLENISHING DEVELOPER, AND IMAGE-FORMING METHOD
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Abstract
An object of the present invention is to provide a two-component developer which can achieve a high-definition image with a smaller toner laid-on level than a conventional one, provides a color gamut comparable to that of printing, can respond to an increase in printing speed, and allows an image with a stable tinge to be formed even in long-term use. The object can be achieved by a two-component developer containing a cyan toner and a magnetic carrier, the two-component developer being characterized in that the cyan toner has the following characteristics: (i) when the concentration of the cyan toner in a solution of the cyan toner in chloroform is represented by Cc (mg/ml) and the absorbance of the solution at a wavelength of 712 nm is represented by A712, a relationship between Cc and A712 satisfies the relationship of 2.00<A712/Cc<8.15; (ii) the lightness L* and chroma C* of the cyan toner determined in a powder state satisfy the relationships of 25.0≦L*≦40.0 and 50.0≦C*≦60.0; and (iii) the absolute value for the triboelectric charge quantity of the cyan toner measured by a two-component method using the cyan toner and the magnetic carrier is 50 mC/kg or more and 120 mC/kg or less.
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Citations
13 Claims
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1-10. -10. (canceled)
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11. An image-forming method, comprising:
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a charging step of charging an electrostatic latent image bearing member; an electrostatic latent image forming step of forming an electrostatic latent image on the electrostatic latent image bearing member charged in the charging step; a developing step of developing the electrostatic latent image formed on the electrostatic latent image bearing member with a two-component developer containing a cyan toner having cyan toner particles each having at least a binder resin and a colorant, and an external additive, and a magnetic carrier to form a cyan toner image; a transferring step of transferring the cyan toner image on the electrostatic latent image bearing member onto a transfer material through or without through an intermediate transfer body; and a fixing step of fixing the cyan toner image to the transfer material, wherein; a laid-on level of the cyan toner of a monochromatic solid image portion having an image density of 1.5 in the cyan toner image unfixed to be formed on the transfer material is in a range of 0.10 mg/cm2 or more to 0.50 mg/cm2 or less; and the cyan toner has the following characteristics; (i) when a concentration of the cyan toner in a solution of the cyan toner in chloroform is represented by Cc (mg/ml) and an absorbance of the solution at a wavelength of 712 nm is represented by A712, a relationship between Cc and A712 satisfies the following expression (1)
2.00<
A712/Cc<
8.15
(1);(ii) a lightness L* and a chroma C* of the cyan toner determined in a powder state satisfy relationships of 25.0≦
L*≦
40.0 and 50.0≦
C*≦
60.0; and(iii) an absolute value for a triboelectric charge quantity of the cyan toner measured by a two-component method using the cyan toner and the magnetic carrier is 50 mC/kg or more and 120 mC/kg or less, wherein in measurement by the two-component method, a sample including 9.2 g of the magnetic carrier and 0.8 g of the toner is prepared in a 50-ml polybottle, the sample in the polybottle is subjected to moisture conditioning at 23°
C. and 60% humidity for 24 hours, the polybottle containing the sample is capped, the polybottle is rotated with a roll mill fifteen times at a speed of one rotation per second, the polybottle containing the sample is shaken at a stroke of 150 times/min so that the toner and the magnetic carrier are mixed for 5 minutes, whereby a developer for measurement is prepared, the prepared developer is placed on a 20 μ
m aperture mesh of a sample holder, the toner is removed from the prepared developer by a suction pressure of 2 kPa for two minutes, and the triboelectric charge quantity (Q) is determined at that time. - View Dependent Claims (12, 13)
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Specification