JPS60201360A - Carrier - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a carrier in a magnetic plan developer for developing electrostatic latent images such as electrophotography and static recording, and more particularly to an improved carrier for use in a developer. It is.

Conventionally, as a method for visualizing an llp latent image using a developer, for example, U.S. Pat.
Magnetic brush method described in Book 11, No. 2618
The cascade development method described in No. 552 is known.

Generally, the developer used in these developing methods is a powder toner in which dyes and pigments are dispersed in a binder, and this toner is applied to an electrostatic latent image formed on a photographic material by an appropriate means. A mixture with a solid support carrier is used to convey the . When mixed with the toner, this solid support carrier acts to impart the desired triboelectric charge to the toner, so that the toner is transported to the latent image and developed.

In a typical developer, a portion of toner, which is one of its components, is lost during development, and that amount is replenished. However, the carrier, which is the other component, is not lost during development and is used repeatedly, so as a large number of copies are made, the following surface The above changes occur.

(1) Collision between carrier and carrier and wall or screen inside the carrier developer +7. - Changes in surface condition due to collisions with various members such as.

(2) A change in surface condition due to the attachment or adsorption of fine toner or some of the constituent components of the toner to the carrier.

In general, the ability of the carrier to impart triboelectric charges to the toner is greatly affected by the material and shape of the carrier, so changes in the surface state of the carrier as described above may occur due to one or more flattenings in the non-image area. #) Increase in #, decrease in density in the image area,
This causes deterioration phenomena such as non-uniformity of the black background over a wide area, and the entire developer must be replaced.

The objects of the present invention are as follows.

(1) Providing a carrier material with high ability to impart triboelectric charge to toner.

(2) Providing a carrier material that has a long life as a developer.

(3) Providing a carrier material for a developer with excellent reproducibility.

(4) Providing a carrier material for a developer with high environmental stability such as high temperature and high humidity, and low temperature and low humidity.

(5) Appropriate control of triboelectric charging properties of toner.

The guanamine derivative (A) and guanamine-based condensate (B) used in the present invention have a structure as shown in the general formula below.

(A) (B) The present invention achieves the above-mentioned object by uniformly coating a carrier with guanamine, a guanamine derivative, or a guanamine-based condensate. That is, by using a carrier containing guanamine, a guanaquin derivative, or a guanamine-based condensate on its surface, the ability to impart minus toride to negative toners can be improved. On the other hand, for conventional digital toners whose uniformity is too strong and the image density decreases due to charge aggregation or other reasons when performing image reproduction durability, we adjust the application of toner to suit the needs of the digital toner. What bird? The value can be controlled.

In the present invention, guanamine or a guanamine derivative,
Alternatively, methods for incorporating a guanamine-based condensate into a carrier core include a method in which these compounds are directly coated, and a method in which guanamine, a guanamine derivative, or a guanamine-based condensate is dispersed in a resin and then coated. Direct coating methods include dissolving or dispersing guanamine, a guanamine derivative, or a guanamine-based condensate in a bath solution, and immersing the carrier in the bath solution, or using powdered guanamine, a guanamine derivative, or a guanamine-based condensate. There are methods such as dry mixing with a carrier. In addition, methods of dispersing in resin and enveloping the carrier are particularly limited, such as by dousing or spraying the carrier core in a resin solution in a bath, or by using a controlled fluidized bed method. It is not something that will be done. The connected material is 0 in terms of resin solid content with respect to the carrier core.
105 to 10 wt% is suitable, more preferably 0
．． It is 5 to 5 wt%. As the resin used, conventionally used resins can be used as they are.

For example, natural resin, polyolefin resin/polyvinyl, polyvinylidene resin, fluorocarbon resin, polyamide resin, I-lyester resin, polyurethane resin, polycarbonate resin, etc. nate resins, phenolic resins, acrylic resins, melamine resins, amino resins, epoxy resins, and mixtures thereof.

For these resins, the content of guanamine, guanamine derivatives, or guanamine-based condensates varies depending on the resistivity of the resin, the state of dispersion in the resin, and the development conditions in which the coated carrier is used. It is preferably 0.1 to 20 parts by weight based on approximately 100 parts by weight of the resin.

Further, as the carrier core used in the present invention, iron powder, j
Conventionally known materials such as rasp beads can be used as is.

Example 1 70 parts by weight of thermosetting acrylic resin (solid content equivalent), 20 parts by weight of melamine resin, 10 parts by weight of epoxy resin, and 15 parts by weight of benzoguanamine in xylene/f-tanol = 77
The mixture was dissolved in the mixed solvent of No. 3 and thoroughly mixed and dispersed using an appropriate dispersion machine, and a solution of No. 1 was prepared using a resin solid content calculator.

This bath liquid is 100? 100 carrier iron powder inside? Pour into a pot and heat while stirring thoroughly to remove the solvent. After removing all the solvent, the coated carrier was poured.

88 parts by weight of this coated carrier and 12 parts by weight of toner mainly composed of polyester resin were mixed and blown.
When the tripo charge amount of toner was measured using the OFF method -12
, 5 μC/f.

When this developer was used to produce an image, an extremely good image was obtained, with good reproducibility of a black background over a wide range, and no practical problems with reeds.

Further, when this developer was used to produce images at 30° C. and high humidity at a crystal temperature of 85 qA, the 2000th image was as good as the first image.

Comparative Example 1 Except for excluding benzoguanamine in Example 1,
A coated carrier was prepared in a manner similar to Example 1. When this carrier was mixed with a toner, the toner had a tripocharge amount of -3.2 μC/iP. When this developer was used to produce images in an environment of 30° C. and 80 pixels in the same manner as in Example 1, fogging was severe from the first sheet and by about the 50th sheet, it exceeded the practical limit.

Example 2 Almost the same as Example 1 except that the coating resin in Example 1 was changed to 80 parts by weight of polyamide resin, 20 parts by weight of phenol resin, and the amount of benzoguanamine added was changed to 10 parts by weight per 100 parts by weight of resin. A coated carrier was obtained. When 88 parts by weight of the obtained carrier and 12 parts by weight of a toner containing styrene acrylic-BMA-dimethylaminoethyl methacrylate resin as a main component were mixed, and the tripo charge amount of the toner was measured by the blow-off method, it was found to be +18. It was .3μC/P. When this developer was used to create an image, both the text and the wide black background were faithfully reproduced in the original, indicating good condition.

Comparative Example 2 A carrier obtained in the same manner as in Example 2 except that the benzoguanamine in Example 2 was removed was mixed with the same toner as in Example 2, and the tripo charge amount of the toner was measured in the same manner, and the result was +55. 2μCI? It happened.

When I created an image using this developer, I found that it was 100%
On the 0th sheet, the image density was low and outside the practical limit.

Example 3 The same procedure as in Example 1 was carried out except that the benzoguanamine base in Example 1 was replaced with a condensate of benzoguanamine and formaldehyde, and the trypo charge amount was measured in the same manner. Indicated. Further, when the same evaluation as in Example 1 was performed, good results were obtained.

Example 4 The same procedure as in Example 1 was carried out except that the benzoguanamine glue 9 was replaced with guanamine. The trig charge amount was measured in the same manner using the carrier obtained. It was -10.5 μC/l. -It was.

When the same evaluation as in Example 1 was performed, similarly good results were obtained.

Claims (1)

[Claims] A carrier characterized by containing guanamine, a guanamine derivative, or a guanamine-based condensate on its surface.