摘要:
A magnetic toner composed of a binder resin and magnetic fine particles, wherein the magnetic fine particles are coated with an iron-zinc oxide on their surfaces and the magnetic fine particles have a saturation magnetization (.sigma.s) of 50 Am.sup.2 /kg or above under a magnetic field of 79.58 kA/m (1K oersted) where the product of residual magnetization (.sigma.r, Am.sup.2 /kg) and coercive force (Hc, kA/m), .sigma.r.times.Hc, is in the range between 60 and 250 (kA.sup.2 m/kg).
摘要:
An image forming method has the steps of forming a toner image by developing through a developing means a latent image formed on a latent image bearing member; transferring the toner image formed, from the latent image bearing member to a transfer medium through a transfer means to which a bias is applied; cleaning the latent image bearing member from which the toner image has been transferred to the transfer medium, to recover and collect the toner remaining on the latent image bearing member; and feeding the toner recovered and collected, to the developing means for reuse in the developing step. The toner has a binder resin and at least one of a magnetic powder and a colorant. The toner has a weight average particle diameter (D.sub.4) of from 4 .mu.m to 11 .mu.m; a coefficient A of variation of number-base distribution, of not more than 40, which is a coefficient represented by the formula: A=S.sub.n /D.sub.1 .times.100 wherein S.sub.n represents a standard deviation of number-base distribution, and D.sub.1 represents a length average particle diameter (.mu.m) on the basis of number; and a coefficient B of variation of volume-base distribution, of not more than 30, which is a coefficient represented by the formula: B=S.sub.W /D.sub.4 .times.100 wherein S.sub.W represents a standard deviation of volume-base distribution, and D.sub.4 represents a weight average particle diameter (.mu.m) on the basis of weight.
摘要:
A toner for developing an electrostatic image is provided as a pulverized mixture including a binder resin and a colorant. The binder resin is characterized by a molecular weight distribution on a GPC chromatogram of its tetrahydrofuran (THF)-soluble resin content including below 15% of a resin component in a molecular weight region of at most 5000 and at least 5 wt. % of a resin component in a molecular weight region of at least 5.times.10.sup.6 and showing a main peak in a molecular weight region of 5000 to 5.times.10.sup.6. The THF-soluble resin component in the molecular weight region of at least 5.times.10.sup.6 is extremely enriched during a melt-kneading step during the toner production, so as to effectively prevent toner flowout from a member for cleaning a fixing roller.
摘要:
An image forming method in which a toner-carrying member for carrying a specific magnetic toner is placed adjacent a latent image-bearing member for carrying an electrostatic latent image so as to form a developing region of a predetermined gap size. The magnetic toner on the toner-carrying member forms a toner layer of a regulated thickness smaller than the above-mentioned gap. An asymmetric bias is applied to the magnetic toner so as to cause the magnetic toner from the toner-carrying member to be conveyed to the latent image-bearing member thereby to develop the electrostatic latent image.
摘要:
A magnetic toner has magnetic resin particles containing at least a binder resin, a charge control agent and a magnetic powder. The surface-modified fine silica powder being a fine silica powder has been treated with a hydrophobicizing agent. The fine silica powder has a specific surface area of not less than 180 m.sup.2 /g, a hydrophobicity of from 60% to 95% and a bulk density of from 35 g/lit. to 49 g/lit.
摘要:
A toner for developing an electrostatic image is constituted by a binder resin and a colorant. The binder resin is characterized by containing at least 20 wt. % of an extraction residue after 6 hours of extraction and below 20 wt. % of an extraction residue after 72 hours of extraction respectively by Soxhlet extraction with tetrahydrofuran. The toner shows a dynamic modulus and a loss modulus, respectively at 200.degree. C. and 0.1 Hz, which are substantially unchanging with time. The properties provide the toner with a harmonization of anti-offset characteristic and fixability as well as stable viscoelasticity under heating.
摘要:
A toner for developing electrostatic images, comprises a binder resin and a colorant, wherein the binder resin comprises a vinyl copolymer having an acid anhydride group, and the binder resin has a total acid value (A) of 2-100 mgKOH/g and a total acid value (B) attributable to acid anhydride group of below 6 mgKOH/g so that [(B)/(A)].times.100 is 60% or less. Because the binder resin has a specified acid value partly attributable to acid anhydride group, the toner is provided with an adequate balance between chargeability and dischargeability, so that the toner shows a stable performance under various environmental conditions. The toner is particularly advantageously constituted as a magnetic toner of fine particle sizes suitably used under application of unsymmetrical alternating bias electric field.
摘要:
A toner for developing electrostatic images, comprises a binder resin and a colorant, wherein the binder resin comprises a vinyl copolymer having an acid anhydride group, and the binder resin has a total acid value (A) of 2-100 mgKOH/g and a total acid value (B) attributable to acid anhydride group of below 6 mgKOH/g so that [(B)/(A)].times.100 is 60% or less. Because the binder resin has a specified acid value partly attributable to acid anhydride group, the toner is provided with an adequate balance between chargeability and dischargeability, so that the toner shows a stable performance under various environmental conditions. The toner is particularly advantageously constituted as a magnetic toner of fine particle sizes suitably used under application of unsymmetrical alternating bias electric field.
摘要:
A monocomponent-type developer for developing electrostatic images, includes a magnetic toner containing at least a binder resin and magnetic powder, and 0.5-10 wt. % (based on the magnetic toner) of inorganic fine powder having a length-average particle size of 0.1-5 .mu.m. The developer has a number-basis particle size distribution such that particles of 4 .mu.m or smaller are contained at 5-18% by number and particles of 4-10 .mu.m are contained at at least 60% by number. The developer has a volume basis particle size distribution such that particles of 12.7 .mu.m or larger are contained at at most 10% by volume. The developer has a weight-average particle size of 7-11 .mu.m. The developer is particularly useful for development under application of a DC-superposed asymmetric AC bias electric field including a development-side voltage component with a larger magnitude and a shorter duration than a reverse development-side voltage component.
摘要:
An image forming method in which a toner-carrying member for carrying a specific magnetic toner is placed adjacent a latent image-bearing member for carrying an electrostatic latent image so as to form a developing region of a predetermined gap size. The magnetic toner on the toner-carrying member forms a toner layer of a regulated thickness smaller than the above-mentioned gap. An asymmetric bias is applied to the magnetic toner so as to cause the magnetic toner from the toner-carrying member to be conveyed to the latent image-bearing member thereby to develop the electrostatic latent image.