JPS62242978A - Image forming device - Google Patents

Abstract

PURPOSE:To constitute the titled device so that deterioration of its function caused by an excess temperature rise is not generated in a photosensitive body, etc., by transferring a toner image to a recording material by using a supercooling toner, and also, heating its toner image to below a melting point of the toner and above a glass transition point, and fixing it at the same time as a transfer. CONSTITUTION:A transferable toner image which has been formed on the surface of a latent image forming body 1 is transferred and fixed to a sheet-shaped transfer material for passing through a pressure contacting nip part of both a cylindrical latent image forming body 1 and a pressure body which is pressed against said body. As for a toner for forming a toner image, a microcapsule toner having a supercooling property is used, and the toner image which has been formed on the surface of the latent image forming body 1 abuts on the sheet-shaped transfer material which is fed through a carrying path 3, in the nip part to match the timing, and the toner image is transferred. In this case, prior to a transfer and a fixation, the toner is heated to below a melting point (130 deg.C), and above a glass transition point (30 deg.C) by a heat source and the work is executed, and the transfer and fixation are executed by setting a linear pressure of the nip part to 3kg/cm.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Object of the Invention (Field of Industrial Application) The present invention relates to an image forming apparatus using electrostatic recording means, such as an electrostatic copying machine and a printer thereof.

(Prior art and issues to be solved) A toner image is electrostatically formed using powder toner on the photosensitive layer on the surface of a photoreceptor, and then this toner image is transferred to a sheet-like recording material, mainly paper, using electrostatic force. Image forming apparatuses configured to fix and fix the toner image onto the recording material by applying pressure or pressure and heat to the recording material carrying the toner image after the toner image have been transferred have been widely used.

It goes without saying that such image forming apparatuses are utilized in various fields with a certain degree of effectiveness, but on the other hand, it is necessary to avoid some drawbacks that are inevitably inherent in the image forming process of these apparatuses. is difficult.

For example, because electrostatic force is used to transfer toner from the photoconductor to the recording material, it is difficult to transfer all of the toner forming a toner image on the photoconductor surface to the recording material, and a considerable amount of toner remains on the photoreceptor as residual toner (transfer rate is usually about 80 to 90%), resulting in excessive toner consumption and low image density.

Furthermore, the toner image once formed on the surface of the recording material is only electrostatically attached to the recording material until it is fixed, so the toner may scatter due to the presence of an electric field or vibration within the device. This unavoidably causes problems such as deterioration of the image and contamination of various parts within the device.

In order to avoid such drawbacks, Japanese Patent Application Laid-Open No. 55-134
As seen in Japanese Patent No. 872 and US Pat. No. 4,195,927, a method has been proposed in which a toner image on a photoreceptor is directly transferred onto a recording material using pressure. However, since such a device requires a pressure of about 200 kg/crn', it is difficult to directly transfer the toner image on the surface of the photoreceptor to the recording material, especially due to the strength of the photoreceptor layer. It was necessary to transfer the image onto a dielectric member and then pressure transfer it onto a recording material.

For this reason, the device inevitably becomes larger and more complicated.

Also, USP No. 3013878, No. 3E189706
As seen in the issue, the toner image formed on the surface of the photoreceptor was transferred to an intermediate transfer member whose surface was made of silicone comb, etc., and then this was transferred and fixed onto the recording material by applying heat. something is proposed.

However, such means require heating to usually 180 to 250°C to reach the melting point of the toner during final transfer, and therefore a large amount of heat is required for fixing. There is a risk that the temperature may rise excessively through the intermediate transfer member, which may adversely affect its characteristics.

The present invention has been made in order to cope with the current situation, and it is possible to perform fixing with high efficiency and low energy consumption through pressure transfer and fixing. It is an object of the present invention to provide an image forming apparatus that can stably produce high-quality images over a long period of time without any deterioration.

(2) Structure of the invention (technical means for solving the problem and its operation) In order to achieve the above object, the present invention provides an image forming apparatus in which a supercooled toner is used as a toner for forming a visible image. is used to transfer the toner image onto a recording material and make it visible.
The present invention is characterized in that the toner image is heated to a temperature below the melting point of the toner and below the glass transition point so that the toner image is transferred and fixed onto the transfer material at the same time.

With this configuration, it is not necessary to apply an excessive amount of heat to the photosensitive layer on the surface of the image carrier particularly during fixing, and images can be formed at a high transfer rate without adversely affecting the properties thereof.

(Description of Embodiment) The attached drawing is a side view of a main part showing an embodiment of an image forming apparatus to which the present invention is applied. A latent image forming body 1 formed by forming a photosensitive layer 1b made of a photoconductive material on the surface of the latent image forming body 1a, a base body 2a made of a rigid material such as steel and in pressure contact therewith, and a silicone rubber layer formed on the surface thereof. The pressure body 2 includes an elastic layer 2b, and a recording material conveyance path 3 including a nip N where these two are pressed together.

As the photosensitive layer, amorphous silicon, organic semiconductor, etc., which have relatively high pressure resistance, are suitable, and furthermore, a material having a surface energy of 35 dynes/cm or less, for example,
It is best to form a photosensitive layer by coating or mixing silicone resin, fluororesin, or a block polymer having these functional groups, and the thickness is 2JLm, preferably 14m or less, and the surface roughness is is 0.5μmRMs or more.

Desirably, it is about 0.2 gm RMS.

The surface elastic layer of the pressurizing body 2, such as urethane rubber, is appropriately determined in the range of 1 to 5 mm depending on the pressing force with the photoreceptor.

Around the latent image forming body, as is well known in this type of image forming apparatus, there are provided a main charger 4 for uniformly charging the photosensitive layer, an image signal writing means 5, and a toner image forming device. A developing device for removing residual toner, a cleaning device for removing residual toner, a static eliminating charger 10 for removing residual charges, a static eliminating lamp 9, etc. are disposed.Furthermore, a heat source 7 for imparting tackiness is disposed. be.

The toner used to form the toner image was a microcapsule toner made by kneading magnetic powder into supercooling polyamide resin and covering it with a thin film of styrene acrylic resin.

With the rotation of the latent image forming body, a toner image formed by the supercooled toner on the surface of the latent image forming body using the capsule described above by each of the well-known image forming members described above,
The toner image contacts a sheet-shaped transfer material (not shown) fed through the conveyance path 3 at the nip portion N at the same time, and the toner image is transferred to the transfer material and firmly fixed thereto. shall be taken as a thing.

At this time, the toner was heated by a heat source to a temperature below the melting point (130°C) and above the glass transition point (30'C), in this case 60°C, prior to transfer and fixing. Further, at this time, the linear pressure at the pressure nip portion between the latent image forming member and the pressure member was set to 3 kg/cm.

When we conducted a continuous paper feeding test under the above conditions, we found that 10
After passing 10,000 sheets, there was no change in the image, no damage to the surface of the latent image forming member, no deterioration of characteristics, and a transfer rate of 99% was obtained.

The transfer rate when using normal toner under similar conditions is 10
%Met.

Furthermore, when using normal toner and performing transfer and fixing using only heat, the surface temperature of the pressure body should be 180 to 250"C.
As it is necessary to heat the photoreceptor to a certain degree, the surface of the photoreceptor reaches 80℃ or higher, which changes the characteristics such as a decrease in dark resistance, making it difficult to obtain a stable latent image. The temperature rise could be suppressed to about 40'C.

(3) Effects of the Invention Since the present invention has the configuration described above, it can achieve a high transfer rate without applying an excessive load to the latent image forming member or deteriorating its characteristics due to excessive temperature rise. This has the effect that stable images can be obtained over a long period of time, and the life of the latent image forming body can be greatly increased.

[Brief explanation of drawings]

The accompanying drawings are side views of essential parts of an embodiment of an image recording apparatus according to the present invention. l...Latent image forming body, 2... Pressure body, 3... Conveyance path, 4... Charger, 5... Image signal writing r first stage, 6...
...Developer, 7...Heat source, 9...Cleaning device.

Claims (2)

[Claims] (1) In an image forming apparatus in which a transferable toner image formed on the surface of a latent image forming member is transferred and fixed onto a sheet-like transfer material that passes through a pressure nip with a pressure member that is in pressure contact with the photoreceptor, An image forming apparatus that forms a toner image using toner that has supercooling properties. (2) The image forming apparatus according to claim 1, wherein the toner is heated to a temperature lower than the melting point and higher than the glass transition point during transfer and fixing.