JPS63135980A - Pressure transfer method for conductive toner image - Google Patents

Abstract

PURPOSE:To decrease generation of defective transfer when humidity is high by subjecting the conductive toner image, which is formed by developing an electrostatic charge image on an image carrier by using a conductive one- component toner added with a specific ratio of a fatty acid metal salt, to pressure transfer. CONSTITUTION:A required effect is obtd. if the conductive one-component toner added with not only zinc stearate but also 0.1-10wt% other fatty acid metal salt as the additive to be added to the conductive one-component toner to prevent the defective transfer of the conductive toner image under the high humidity is used. The other fatty acid metal salts are exemplified by stearic acid metal salt, dibasic lead stearate, oleic acid metal salt, palmitic acid metal salt and the mixture composed thereof; the zinc stearate is most preferable in practicability. The generation of the defective transfer in the high humidity environment is thereby decreased.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a method of forming an electrostatic image on an image bearing member, which is used in image forming apparatuses such as copying machines, facsimiles, and printers, using a conductive one-component toner. The present invention relates to a pressure transfer method for a developed conductive toner image.

[Conventional technology]

Generally, development of electrostatic latent images using conductive single-component toner used in image forming devices such as copying machines and printers is carried out at an extremely low latent image potential of about 150 to 400 μm. It is often used in ionography, where the image potential is not very high, and in cases where a latent image is formed using a multi-needle electric bridge head. However, in order to transfer a toner image formed by conductive toner onto recording paper, transfer by corona discharge is not performed due to the low chargeability of conductive toner, and transfer efficiency can also be improved by transfer using a conductive roller. Therefore, pressure transfer using a pressure transfer roller is suitable, as shown in Japanese Patent Publication No. 57-501348, for example, and a high transfer efficiency of up to 99% has been obtained.

[Problem that the invention seeks to solve]

However, when transferring a conductive toner image formed using such conductive toner to recording paper using a pressure transfer method, pressure transfer is performed in a high temperature environment, or if the image is exposed to a high temperature environment for a long time. When pressure transfer is performed using recording paper, there is a problem that a transfer failure occurs in which the conductive toner image on the image carrier is not partially or completely transferred to the recording paper.

The present invention has been made in order to solve the above-mentioned eight problems in the conventional pressure transfer method of conductive toner images. We promise to provide a method.

[Means and operations for solving the problems] In order to solve the above problems, the present invention reduces the electrostatic charge image on the image carrier to 0.
．． By pressure-transferring a conductive toner image formed by developing a conductive one-component toner to which 1 to 1.0 wt% of fatty acid metal salt has been added, the occurrence of transfer defects at times of high humidity is reduced. be.

At high temperatures, the affinity of the conductive toner for the recording paper decreases, lowering the affinity of the conductive toner for the image carrier, resulting in poor transfer. By adding an appropriate amount of fatty acid metal salt to the film, it is possible to reduce the occurrence of transfer defects at high humidity. This is because the addition of fatty acid metal salts improves the affinity of the conductive toner for the recording paper, which absorbs moisture, and at the same time reduces the affinity of the conductive toner for the image carrier, which has a relatively low ability to absorb moisture. This seems to be due to the fact that the occurrence of transfer defects is prevented.

Addition of 0.1 wt% of fatty acid metal salts has the effect of reducing the occurrence of transfer defects at high humidity, while addition of 1.0 wt%
If it exceeds wt%, not only will the fluidity decrease and good developability will be inhibited, but also the conductivity will decrease and poor development will occur, so the amount of fatty acid metal salt added is 0.1 to 1.0 wt.
A range of % is a valid and appropriate value.

〔Example〕

Examples will be described below. First, in order to compare the transferability at high humidity, a conductive one-component toner without additives was prepared as follows. That is, 35 wt% polyethylene resin, 60 wt% magnetic powder, and 5% carbon blank as a coloring agent were mixed, melted and kneaded at high temperature, then crushed and classified to give 10%
Both fine powder with a particle size of less than 8 m and coarse powder with a particle size of more than 32 μm are 3% or less, and the average particle size is 20 μm and 10
A conductive one-component toner was prepared in which 94% or more of the particles had a particle size of ~32 μm. The purpose of cutting fine powder with a particle size of less than 108 m was to prevent the generation of dirt in the machine due to fine powder, and the purpose of cutting coarse powder with a particle size of more than 32 μm was to prevent deterioration of N1r due to such coarse powder. This is to prevent this.

Next, the conductive one-component toner prepared in this manner is applied to an image forming apparatus equipped with a pressure transfer mechanism as shown in FIG. After leaving the paper for a day and night, a solid of 20 square centimetres (
Images with solid black areas were printed out to examine the occurrence of transfer defects to recording paper.

The image forming apparatus shown in FIG. 1 generates an ion flow modulated in accordance with an image signal to be recorded by a recording head 2 equipped with an ion flow generation device onto a dielectric drum 1 rotating in the direction of the arrow. A dot-like image is projected to form an electrostatic charge image, which is converted into a toner image by toner development in a developing device 3.
This toner image is pressed against the dielectric drum l disposed below the recording paper conveyance path at a high pressure of, for example, 1 ton,
A pressure transfer roller 4 rotates following the rotation of the drum 1.
It is configured so that the image is transferred onto the recording paper 7. In the figure, 5 is a toner removing device for cleaning the toner remaining on the dielectric drum I without being transferred to the recording paper 7 in the transfer section, 6 is a static eliminator for removing static charges, and 8 is a device for the transfer section. A paper feed tray 9 is a paper discharge tray in which the recording paper to be conveyed is stacked and stored.

Next, carbon black, silica powder, polytetrafluoroethylene (Teflon) powder, and zinc stearate, which is a fatty acid metal salt, were added as additives to the conductive one-component toner having the above structure without adding any additives. , were added in different amounts to prepare conductive one-component toners with similar particle sizes.

The carbon black to be added has the same particle size (approximately 0.1 μm) as that contained in the conductive one-component toner prepared without adding any additives, and has the same particle size (approximately 0.1 μm) as the silica powder. Teflon powder has a particle size of 0.1 μm, Teflon powder has an average particle size of 7 μm (for example, Daikin Industries, Ltd. "Luburon L-5"), and zinc stearate has an average particle size of 0.1 μm (for example, (Reagent manufactured by Wako Pure Chemical Industries, Ltd.) was used.

Then, using the image forming apparatus shown in FIG. 1 above, the state of transferability was examined under the same conditions at high temperature and high humidity. The results are shown in Table 1. In the experiment, each sample was printed out on 10 sheets of recording paper, and the number of sheets in which transfer failure occurred in the solid portion was determined.

Table 1 As can be seen from Table 1 above, in case 1 using a conductive monocomponent toner without additives, transfer defects occurred on all recording papers. In addition, when using a conductive one-component toner in which 2 wt% of carbon blank was added to this toner, and 0.5 wt% and 1.0 w of silica powder were used.
Even when using conductive single-component toner with t% added, transfer defects occurred on 10 sheets of recording paper, and these additives have no effect at all in preventing transfer defects at high humidity. It has been found.

Furthermore, if carbon black is added in an amount greater than the amount shown in Table 1, the carbon black will adhere around the solid area, resulting in a significant deterioration of image quality. If the above amount was added, the resistance of the conductive one-component toner would increase, resulting in blurring of the image, resulting in a significant deterioration of the image quality.

In the case of Teflon powder, when it was added up to 10.0 wt%, transfer defects were slightly improved, but there was a problem that the resistance of the toner increased, causing image blurring and deteriorating the image quality. Ta.

On the other hand, when a conductive single-component toner containing zinc stearate is used, the effect of preventing transfer defects appears at the addition of 0.1 wt%, and when 0.5 wt% is added, the occurrence of transfer defects is completely eliminated. was able to prevent it. However, if the amount of zinc stearate added exceeds 1.0 wt%, although transfer defects will not naturally occur, the fluidity of the toner will decrease, and good developability will be hindered. This causes problems such as increased toner resistance and blurring of images. Therefore, the effective appropriate value for the amount of zinc stearate added is 0.1 to 1.0 wt%.

In addition, the additives added to the conductive single-component toner to prevent defective transfer of conductive toner images under high humidity include not only zinc stearate but also other fatty acid metal salts at 0.1
=1. Similar desired effects were obtained when using a conductive monocomponent toner containing Owt%. Other fatty acid metal salts include, for example, cadmium, barium, lead, iron 1
w4. Stearate metal salts with metals such as nickel, cobaluroaluminum, magnesium; dibasic lead stearate: zinc, magnesium, lead, iron 2w4. cobalt.

Oleic acid metal salts with metals such as calcium; palmitic acid metal salts with metals such as aluminum and calcium;
Examples include mixtures thereof.

However, for practical purposes, zinc stearate is the most preferred.

Note that the conductive one-component toner containing zinc stearate used in the above embodiments was shown in which zinc stearate was externally added to the conductive one-component toner and used by stirring. Of course, similar effects can be obtained by adding zinc stearate to a resin such as polyethylene resin constituting the toner during the toner manufacturing process, or by adding zinc stearate to the toner surface by heat treatment.

Further, in the above example, a conductive one-component magnetic toner with a fatty acid metal salt added thereto was shown, but a toner formed using a non-magnetic conductive one-component toner with the predetermined amount of a fatty acid metal salt added thereto. Of course, the same effect of preventing transfer defects can also be obtained when pressure transfer of a conductive toner image is performed.

Furthermore, in the above embodiments, an image forming apparatus using a dielectric drum as an image carrier has been described. Even if a photosensitive drum such as C) is used, the occurrence of transfer failure of the developed conductive toner image can be effectively prevented. Further, the shape of the image carrier is not limited to a drum shape, and similar effects can be obtained when pressure transfer of a conductive toner image is performed using a belt-shaped image carrier.

〔Effect of the invention〕

As described above based on the embodiments, according to the present invention, a conductive toner image formed by development with a conductive monocomponent toner to which 0.1 to 1.0 wt% fatty acid metal salt is added is pressure-transferred. As a result, it is possible to reduce the occurrence of transfer defects in a high temperature environment, and even when pressure transfer is performed using the LII wet roller in a high temperature environment, transfer defects do not occur, and the transfer rate is the same as that at room temperature. Recorded images with good image quality can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of the configuration of an image forming apparatus for carrying out the method of pressure transfer of a conductive toner image according to the present invention. In the figure, 1 is a dielectric drum, 2 is a recording head, 3 is a developing device, 4 is a pressure transfer roller, 5 is a toner removing device,
6 is a static eliminator, 7 is a recording paper, 8 is a paper feed tray, and 9 is a paper discharge tray.

Claims (1)

[Claims] In a pressure transfer method for a conductive toner image, in which a conductive toner image formed on an image carrier by developing an electrostatic charge image with a conductive monocomponent toner is pressure-transferred onto a recording paper by a pressure transfer roller, Electrostatic charge image of 0.1 to 1.0
A conductive product characterized by reducing the occurrence of transfer defects at high humidity by pressure-transferring a conductive toner image formed by developing a conductive one-component toner to which wt% of fatty acid metal salt is added. Pressure transfer method for sexual toner images.