Charge control resin particles and toner for developing electrostatic images

Abstract

Charge control resin particles comprising a mixture of at least a charge control agent and a resin, wherein a crystalline zinc 3,5-di-tert-butylsalicylate represented by General Formula below, and having major peaks of X-ray diffraction using the CuKα-characteristic X-ray at Bragg angles 2θ of at least 6.4±0.2° and 15.4±0.2°, is contained as said charge control agent. Toner for developing electrostatic images which comprises a coloring agent, a binder resin for toner, and the charge control resin particles.

1 . Charge control resin particles comprising a mixture of at least a charge control agent and a binder resin for toner to form the resin particle, the mixing ratio by weight of the charge control agent and the resin being 1:9 to 9:1, wherein a crystalline zinc 3,5-di-tert-butylsalicylate having major peaks of X-ray diffraction using the CuKα-characteristic X-ray at Bragg angles 2θ of at least 6.4±0.2° and 15.4±0.2° represented by General Formula (1) below is contained as said charge control agent:  
     
       
         
         
             
             
         
       
     
     in Formula (1), t-Bu represents a tert-butyl group.  
   
   
       2 . Charge control resin particles of  claim 1  wherein said zinc 3,5-di-tert-butylsalicylate has major peaks of X-ray diffraction using the CuKα-characteristic X-ray at Bragg angles 2θ of at least 5.7±0.2°, 6.4±0.2° and 15.4±0.2°.  
   
   
       3 . Charge control resin particles of  claim 1  wherein said zinc 3,5-di-tert-butylsalicylate has major peaks of X-ray diffraction using the CuKα-characteristic X-ray at Bragg angles 2θ of at least 5.2±0.2°, 5.7±0.2°, 6.4±0.2°, 6.7±0.2° and 15.4±0.2°.  
   
   
       4 . Charge control resin particles of  claim 1  wherein said zinc 3,5-di-tert-butylsalicylate is obtainable by adding a solution containing a zinc provider to a solution and/or dispersion liquid of 3,5-di-tert-butylsalicylic acid to cause a reaction between the zinc provider and the 3,5-di-tert-butylsalicylic acid.  
   
   
       5 . Charge control resin particles of  claim 1  wherein said charge control agent consists essentially of the aforementioned crystalline zinc 3,5-di-tert-butylsalicylate.  
   
   
       6 . Charge control resin particles of  claim 1  wherein said charge control resin particles are cooled, solidified and milled particles of a thermally kneaded product of the mixture of at least said charge control agent and said resin.  
   
   
       7 . Charge control resin particles of  claim 1  consisting essentially of said binder resin and said charge control agent.  
   
   
       8 . Charge control resin particles of  claim 1  containing substantially no coloring agent.  
   
   
       9 . Charge control resin particles of  claim 1  wherein the average particle diameter of said charge control resin particles is not more than 10 μm.  
   
   
       10 . Toner for developing electrostatic images, which is prepared from a coloring agent, a binder resin for toner, and charge control resin particles, 
 said charge control resin particles comprising a mixture of at least a binder resin for toner to form the resin particle and a crystalline zinc 3,5-di-tert-butylsalicylate having major peaks of X-ray diffraction using the CuKα-characteristic X-ray at Bragg angles 2θ of at least 6.4±0.2° and 15.4±0.2° represented by General Formula (1) below as a charge control agent,    said crystalline zinc 3,5-di-tert-butylsalicylate being dispersed in a mixture of said binder resin for toner and said binder resin for toner to form the resin particles:                          in Formula (1), t-Bu represents a tert-butyl group.    
   
   
       11 . Toner of  claim 10  wherein said zinc 3,5-di-tert-butylsalicylate has major peaks of X-ray diffraction using the CuKα-characteristic X-ray at Bragg angles 2θ of at least 5.7±0.2°, 6.4±0.2° and 15.4±0.2°.  
   
   
       12 . Toner of  claim 10  wherein said zinc 3,5-di-tert-butylsalicylate has major peaks of X-ray diffraction using the CuKα-characteristic X-ray at Bragg angles 2θ of at least 5.2±0.2°, 5.7±0.2°, 6.4±0.2°, 6.7±0.2° and 15.4±0.2°.  
   
   
       13 . Toner of  claim 10  wherein said zinc 3,5-di-tert-butylsalicylate is obtainable by adding a solution containing a zinc provider to a solution and/or dispersion liquid of 3,5-di-tert-butylsalicylic acid to cause a reaction between the zinc provider and the 3,5-di-tert-butylsalicylic acid.  
   
   
       14 . Toner of  claim 10  wherein the charge control resin particles consist essentially of said binder resin for toner to form the resin particle and charge control agent.  
   
   
       15 . Toner of  claim 10  wherein the charge control resin particles contain substantially no coloring agent.  
   
   
       16 . Toner of  claim 10  wherein the mixing ratio by weight of the charge control agent and the resin in the charge control resin particles is 1:9 to 9:1.  
   
   
       17 . Process for manufacturing toner for developing electrostatic images comprising: 
 mixing at least charge control resin particles which are cooled, solidified and milled particles of a thermally kneaded mixture of at least a binder resin for toner to form the resin particle and a charge control agent, a coloring agent and a binder resin for toner, wherein an active ingredient of said charge control agent is a crystalline zinc 3,5-di-tert-butylsalicylate having major peaks of X-ray diffraction using the CuKα-characteristic X-ray at Bragg angles 2θ of at least 6.4±0.2° and 15.4±0.2° represented by General Formula (1) below;    kneading the mixture in a molten state; and    cooling, solidifying and then pulverizing the mixture to obtain a toner containing the charge control agent dispersed in a mixture of said binder resin for toner and said binder resin for toner to form the resin particles:                          in Formula (1), t-Bu represents a tert-butyl group.    
   
   
       18 . Process of  claim 17  wherein said zinc 3,5-di-tert-butylsalicylate is obtainable by adding a solution containing a zinc provider to a solution and/or dispersion liquid of 3,5-di-tert-butylsalicylic acid to cause a reaction between the zinc provider and the 3,5-di-tert-butylsalicylic acid.  
   
   
       19 . Process of  claim 17  wherein the charge control resin particles consist essentially of said binder resin and charge control agent.  
   
   
       20 . Process of  claim 17  wherein the charge control resin particles contain substantially no coloring agent.  
   
   
       21 . Process of  claim 17  wherein the mixing ratio by weight of the charge control agent and the resin in the charge control resin particles is 1:9 to 9:1.