JPH04186250A - Electronic printing toner - Google Patents

Abstract

PURPOSE:To improve toner fixity to a printing master and mechanical strength and print resistance of a toner image by containing high-density polyethylene PE having a density of a specific or more value in the toner. CONSTITUTION:High-density PE having a density of 0.95 or more is contained in toner used for an electronic printing method. Density of less than the said value deteriorates print resistance, and continuous printing produces a background fog and a broken image etc. Adding of the PE of 0.1 - 10wt.% is preferable. The toner can be prepared by melting, kneading, grinding, and then classing a resin component such as styrene-acrylic copolymer, a color toner conditioner such as carbon black, an electrification control agent such as a nigrosine dye, and the said PE.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is a developer used in an electronic printing device applying the principle of electrophotographic copying, and in particular, a developer that has improved conductivity in the toner image area of a printing master. Regarding toner for electronic printing.

(Prior Art) Printing by electrophotography has been known for a long time. For example, the zero printing method in U.S. Patent No. 2,576,047, or the
There is an electronic printing device disclosed in Japanese Patent No. 554. They form a powder image on a photoconductive plate by an electrostatographic method, and are fused or fixed to form a non-photosensitive insulating image figure, that is, a printing master, on the photoconductive plate, and then, After this printing master has been uniformly charged, the charge is maintained on the non-photosensitive image areas by irradiating it with light in a negative direction, and discharged on the photosensitive non-image areas, transferring the charged powder to the charged area. This is a method in which a powder image is formed by adhering to a powder, and the powder image is transferred onto a suitable image support, and the above steps are repeated.

FIG. 1 is a conceptual diagram of such an electronic printing device.

Around the rotating drum 1, there are provided an exposure lamp 13 in the rotational direction of the drum, a developing device 5, a transfer corotron 6, a flash fixing device 7, a cleaner lamp 15, and a cleaning device 8.
, a charger 4 are arranged.

To create a print master, a photosensitive paper 10 such as zinc oxide paper is wrapped around a rotating drum 1 and then charged with a charger 4. The original on the document table 3 illuminated by an illumination lamp 14 is placed on a projection lens 2.
is projected onto the photosensitive paper 10 via the electrostatic latent image, forming an electrostatic latent image. Next, the latent image is visualized by a developing device 5, and the powder toner image is melted and fixed onto the photosensitive paper 10 by a fixing device 7, thereby forming a printing master.

Next, in electrostatic printing, a printing master having a toner image is charged with a charger 4, and the entire surface is uniformly exposed with a negative exposure knob 13. The charge on the photosensitive paper 10 is washed away by uniform exposure leaving only the toner image portions which are insensitive and non-photoconductive. In other words, since it is possible to obtain a printing master in which only the toner image portion has an electric charge, the toner image on the printing master is visualized by the developing device 5, and the transfer paper 11 is sent to the transfer section of the rotating drum 1, and the toner image on the printing master is transferred by the transfer flotron 6. Transfer to transfer paper. Then, the image is fixed into a fixed image by the fixing device 9, and a copy is obtained from the paper discharge tray 12.

The residual toner on the print master after the transfer is cleaned by the cleaning device 8 to complete one printing cycle. Thereafter, the printing cycle is repeated for two copies of the copy.

In this way, the electronic printing method requires two development steps: one for master creation and one for copy printing, but these two development steps can be performed using the same development device. Preferably, one type of toner is used to create a master and to create a copy.

(Problem to be Solved by the Invention) By the way, in the electronic printing method, printing durability of the plate-made B]printer is also an important factor. There is a method of increasing the mechanical strength of the toner image of the printing master L by increasing the molecular weight of the toner, but such toner has poor fixability to the printing master.

On the other hand, if the molecular weight of the resin is lowered in order to improve the fixability to the printing master, problems such as abrasion of the plate-making master and image disturbance will occur.

SUMMARY OF THE INVENTION Therefore, the present invention aims to solve the problems listed in item L and provide a toner for electronic printing that has good fixability to a printing master and has excellent printing durability.

(Means for Solving the Problems) The present invention involves uniformly charging an electronic printing master having a toner image flash-fixed on a photoreceptor, exposing the entire surface to light, and then performing development, transfer, and flash fixation. This toner is characterized in that it contains high-density polyethylene having a density of 0.95 or more, which is used in an electronic printing method for obtaining copies. Note that the density of the above polyethylene was measured according to JIS6760.

The high density polyethylene used in the present invention has a density of 0.9
If it is less than 5, the rigidity resistance will be poor and continuous printing will cause background fog, image loss, image disturbance, etc. Further, the molecular weight of the polyethylene is optimally in the range of 2,000 to 20,000, and the amount added is appropriately in the range of 0.1 to 10% by weight, preferably 0.5 to 5% by weight. If the molecular weight is too small or the amount added is too large, the powder fluidity of the toner will deteriorate, which may cause uneven plate making during master plate making. On the other hand, if the molecular weight is too large or the amount added is too small, the effect of adding high density polyethylene will not be apparent.

In the present invention, carbon black or a pigment can be added as a color tone adjusting agent.

Further, as the resin component used in the toner, known natural and synthetic resins can be used alone or in a blend. For example, vinyl homopolymers or copolymers such as substituted or unsubstituted styrene, acrylic acid, methacrylic acid or their fatty acid esters, unsaturated olefinic polymers or copolymers such as ethylene and propylene, and its halogenated homopolymers or copolymers, polyamides,
Resins made of condensation polymers such as polyester can be arbitrarily selected depending on the required characteristics.

In addition, charge control agents may be used as needed, such as known various nigrono dyes, quaternary ammonium salts, amines, pyridinium salts, picolinium salts, etc. for positive charging, and azo dyes for negative charging. chromium complex salt, copper phthalonanine, etc. can be added.

Toners containing these components are usually obtained by melt-kneading, followed by coarse pulverization and fine pulverization to obtain fine powder particles with a particle size of 10 to 15 μm, but other known methods such as spray drying, suspension It can also be obtained by a turbidity polymerization granulation method. Further, classification may be performed as necessary, and a flow aid such as finely powdered silica may be attached to the toner surface.

The toner thus obtained usually has a particle size of 50 to 10
The developer is mixed with a carrier, which is magnetically sensitive particles of 00 μm, in an appropriate ratio. As the magnetically sensitive particles, iron powder, ferrite powder, nickel powder, etc. are generally used. In addition,
An organic polymer layer may be provided on the surface of the particles.

(Function) The present invention provides a toner for electronic printing, and the toner has a JIS standard.
By adding high-density polyethylene with a density of 0.95 or more measured in 676 (L), it has good fixing properties to the printing master and the mechanical strength of the fixed toner image is high.
It is possible to provide a toner for electronic printing that has excellent printing durability and can produce printed matter with stable high image quality even in continuous printing.

(Example) Styrene-acrylic copolymer (80/20) 10
0 parts carbon black (manufactured by Capo, Inc., Regal 330) 10 parts Nigrone dye (manufactured by Orient Chemical Co., Ltd., Bontron N-03) 3 parts high-density low molecular weight polyethylene (manufactured by Hoechst Company, 1 PE 30)
Co-molecule M 9000, density 0.97) 3 parts or more of the ingredients are melt-kneaded using a Banbury mixer, cooled, pulverized using a jet mill, and classified to obtain an average particle size of 11 mm.
I got + toner.

(Example 2) High-density low-molecular weight manufactured by Sanyo Chemical Co., Ltd. was used instead of the high-density low-molecular weight polyethylene PE-130 of Example 1! polyethylene 2
A toner was obtained in the same manner as in Example 1 by adding 3 parts of 00P (molecular weight 5000, density 0.97).

(Example 3) In place of the high density low molecular weight polyethylene PE-130 of Example 1, 3 parts of high density low molecular weight polyethylene 400P (molecular weight 4000, density 0.98) manufactured by Mitsui Petrochemicals was added, and Example 1 Got the toner as well.

(Comparative Example 1) A toner was obtained in the same manner as in Example 1 except that the high-density, low-molecular-weight polyethylene of Example 1 was omitted and the other conditions were the same as in Example 1.

(Comparative Example 2) In place of the high-density, low-molecular-weight polyethylene PE-130 of Example 1, 3 parts of high-density, low-molecular-weight polyethylene 210P (molecular weight: 2000, density: 0.94) manufactured by Mitsui Petrochemicals was added, and Example 1 Got the toner as well.

(Comparative Example 3) Instead of the high-density, low-molecular-weight polyethylene PE-130 of Example 1, a low-molecular-weight polypropylene wax Viscole 660P (molecular weight 3000, density 089
) to obtain a toner in the same manner as in Example 1.

(Evaluation of Toner) Three parts of each of the above toners were mixed with 100 parts of steel powder having a particle size of 100 μm as a carrier to prepare a developer for electronic printing.

The toner was evaluated using a Zero Printer 100 printing machine (manufactured by Fujikami Rosoku Co., Ltd.), and the printed sample was fixed while supplying anti-offset liquid (silicone oil) to the fixing roll. Note that flash fixing was used only during master plate making.

Then, a continuous printing test was performed using the same master,
The copies were examined for solid density, background cuffing, image loss, and image disturbance. The evaluation was performed at a temperature of 10°C and a humidity of 15%.
It was conducted under the following conditions.

(Effects of the Invention) By adopting the above configuration, the present invention improves the fixing property to the printing master, and increases the mechanical strength of the fixed toner image, resulting in stable printing even in continuous printing. It is now possible to provide a toner for electronic printing that can produce high-quality printed matter and has excellent printing durability.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of an electronic printing device that can use the toner of the present invention.

Claims (2)

[Claims] (1) Used in an electronic printing method to obtain a copy by uniformly charging an electronic printing master having a toner image flash-fixed on a photoreceptor and exposing the entire surface to light, followed by development, transfer, and fixing. A toner for electronic printing, characterized in that the toner contains high-density polyethylene having a density of 0.95 or more. (2) The toner for electronic printing according to claim (1), characterized in that 0.1 to 10% by weight of high-density polyethylene is added.