JPS62134674A - Image recorder - Google Patents

Abstract

PURPOSE:To obtain a high transfer rate and distinct pictures by pressing a photosensitive body, two transfer rolls, and a pressuring and heating roll to one another vertically with prescribed contacting pressures. CONSTITUTION:A photosensitive body 1, two transfer rolls 2 and 3, and a pressuring heat roll 4 are pressed to one another vertically with prescribed contacting pressures, and heat sources 11 and 12 are provided in rolls 3 and 4. The contacting pressure between the photosensitive body 1 and the transfer roll 2 is set to 5-10kg/cm<2>, and that between transfer rolls 2 and 3 is set to 10-20kg/cm<2>, and that between rolls 3 and 4 is set to 30-50kg/cm<2>. Since a toner image is always transferred with pressures till the transfer process, scattering of a toner an disturbance of the image are not disturbed, and 95-99% high transfer efficiency is attained, and distinct pictures are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Object of the Invention (Field of Industrial Application) This invention relates to an image recording apparatus that performs simultaneous transfer and fixing using pressure and heat.

(Prior art and issues to be solved) A toner image formed on the surface of an image carrier is transferred to a sheet-like transfer material mainly made of paper using electrostatic adsorption force, and then this toner image is supported. Image forming apparatuses that apply pressure or pressure and heat to a transfer material to fix and fix a toner image have been widely used to date.

There is no doubt that such a device is useful from a practical standpoint, but since the toner image is electrostatically transferred to the transfer material, it is difficult to form a toner image. The rate at which the toner supplied to the image carrier is actually transferred to the transfer material is only 80 to 90%, and a considerable amount of toner is wasted, and at the same time, the image density is inevitably reduced.

In addition, after transfer, the toner simply adheres to the transfer material due to electrostatic force, so the bond between the two is weak, and for this reason, the toner may be damaged by the electric field inside the device or vibrations of various parts of the device. This has the disadvantage of causing scattering and disturbance of the toner image.

Also, after the electrostatic latent image formed on the photoreceptor is visualized, it is transferred to an intermediate transfer member made of silicone rubber, etc., and then this toner image is transferred and fixed by applying heat to the final transfer material. However, U.S. Patent No. 3,013.878;
It is disclosed in the specification of No. 889,708 and the like.

However, in this type of product, a large amount of heat is applied that reaches near the melting point of the toner, and this heat is transferred to the photoreceptor through the intermediate transfer member, causing it to heat up and improve its characteristics. There was a risk of damage.

The present invention has been made to address the above-mentioned current situation, and is an image recording method that consumes less energy, has less risk of damaging the photoreceptor and other members, and provides high-quality images with high transfer efficiency. The purpose is to provide a device.

(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 bearing member for forming a toner image, and an image bearing member that is in pressure contact with the image carrier to press the toner image. a first intermediate transfer body that transfers and receives the toner image by pressure contact with the intermediate transfer body and transfers and receives the toner image using a pressure higher than the pressure and heat; The apparatus is characterized by comprising a pressure body for transferring and fixing the toner image onto the transfer material by applying pressure to the transfer material and using heat and a pressure higher than the above-mentioned high pressure.

With this configuration, excessive heat is not supplied to the photoreceptor and the photosensitive layer thereof is not damaged, and the toner is maintained during the entire process of fixing the toner image formed on the image carrier to the transfer material. Since it is always firmly attached to the transfer material, toner scattering and image disturbance will not occur. In addition, since all the transfer action is performed by pressure, the transfer rate is high and clear images can be obtained.

(Description of Embodiments) Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic side view showing the configuration of an image recording apparatus to which the present invention is applied, in which an image carrier (referred to as a photoreceptor) is provided with a photosensitive layer on its surface and formed in a rotating cylindrical shape in a housing IO. 1, a transfer roller 2 which is a first intermediate transfer body which is pressed against this with a predetermined pressure, a transfer roller 3 which is a second intermediate transfer body which is in pressure contact with this and has a heat source inside, and further, It is equipped with a pressure heating roller 4 which is a pressure member that is in pressure contact and has a heating source arranged inside, and a means for passing a sheet-like transfer material such as paper between the transfer roller 3 and the pressure heating roller 4. are doing.

The process of forming a toner image on the photoconductor is basically the same as that in a well-known copying machine, and for this purpose, a primary charger is installed around the photoconductor l to uniformly charge the photoconductor layer. 5. Image signal writing means 6 for forming an electrostatic latent image thereon, a developing device 7 for supplying toner to the latent image to form a visible toner image, and residual toner remaining on the surface of the photoreceptor even after transfer. A cleaner 8 for removing residual charges on the surface, and a residual charge removing means 9 comprising a static eliminating charger, a static eliminating lamp, etc. for removing residual charges on the surface are provided.

Heat sources 11 and 12 such as halogen heaters are arranged inside the transfer roller 3 and pressure heating roller 4, respectively. The surface of roller 4 is 100-
The temperature is maintained at 110°C.

The contact pressure between the photoreceptor 1 and the transfer roller 2 is 1 to 10
Kg/cm', preferably 5-10Kg/cm'
The contact pressure between the transfer roller 2 and the transfer roller 3 is
10 to 20 Kg/cm'', and the contact pressure between the transfer roller 3 and the pressure heating roller 4 is 30 to 50 Kg/cm.
It shall be determined appropriately within the range of cm'.

The photosensitive material is made of aluminum, aluminum alloy, and copper alloy.
It is constructed by forming a photosensitive layer made of amorphous silicon, amorphous selenium, an organic semiconductor, etc. on the surface of a cylindrical core metal having a thickness sufficient to withstand the pressing force with the transfer roller. Note that a substance having a surface free energy of 35 dynes/cm or less, such as a silicone resin, a fluororesin, or a block polymer having a functional group thereof, may be formed on the surface of the photosensitive layer, or the two may be mixed. Preferably, a photosensitive layer is formed.

The thickness of the photosensitive layer formed at this time is 2JLra or less,
Desirably, the IJL is 11 or less, and the surface roughness is 0. 5gm
RMs or less, preferably 0.2 gIIIRMS or less.

The transfer rollers 2 and 3, which are first and second intermediate transfer bodies, have a cylindrical core metal surface made of a rigid material such as steel, and a core metal surface having a thickness that can withstand pressure from adjacent members. Depending on the pressure, a film of resin such as silicone rubber or urethane rubber is formed to a thickness of 1 to 5 mm.

The pressure heating roller 4 has a resin with excellent compression resistance such as polyacetal, polyimide, or polycarbonate applied to the surface of a core metal made of a rigid material such as steel, for a length of 2 to 5 m depending on the contact pressure.
A film is formed to have a thickness of m. Note that the surface of the steel roller may be coated with a highly releasable resin such as Teflon.

As mentioned above, an appropriate heating source 11.12 such as a halogen heater or a planar heating element is installed inside the transfer roller 2.3, which heats the surface of the roller 2 to 80 to 90°C.
In addition, the surface of the roller 3 is maintained at 100 to 110°C.

To briefly explain the operation of the image recording device explained above,
When the image recording operation is started by synchronously rotating everything from the photoreceptor l to the pressure heating roller 4 in the direction of the arrow shown in the figure, the toner image formed by the charger 5, the image signal writing means 6, and the developing device 7 is transferred to the transfer roller 2. The image reaches the nub portion N1 in pressure contact with the roller, and is transferred to the transfer roller by the contact pressure between the two.

At this time, the toner that does not contribute to the transfer and remains on the photoreceptor is removed by the cleaner 8, and the residual charge is removed by the residual charge removing means 9, and the toner is prepared for the next step.

The toner image transferred to the transfer roller 2 reaches a nip portion N2 with the transfer roller 3 as the roller 2 rotates, and the toner image is further transferred to the transfer roller 3 by the contact pressure between both rollers.

The toner image transferred to the transfer roller 3 is then
J! ! It reaches the pressure nip N3 with the roller 4, and at this position, it is taken out from the cassette 13 and the registration roller 1 is removed.
4, the toner image contacts the transfer material traveling along the conveyance path in synchronization with the toner image, and is transferred and fixed on the transfer material at the same time by pressure and heat, and the thus completed copy advances along the conveyance path 15. and is discharged to the outside of the apparatus and reaches the tray 16.

Note that residual toner remaining on the surface of the transfer roller 2.3 after transfer is removed by cleaners 8a and 8b, respectively.

With the above-mentioned apparatus, a photoreceptor having an organic semiconductor covered with a silicone resin is used as a photoreceptor layer, and a transfer roller 2.3 is used.
When copying was carried out using a toner made by mixing a kneaded mixture of low and medium molecular weight polyester with a magnetic material, pulverizing and classifying it, the nip area For N1, transfer pressure is 5Kg/c
99f6 at m'', transfer pressure 20 at nip part N2
Kg/cm', 9 at 90°C surface temperature of transfer roller 3
8%, and transfer pressure of 50 kg at nib part N3
/ am', a transcription rate of 99% was obtained.

When electrostatic transfer was performed directly from the photoreceptor to a transfer material under similar conditions, the transfer rate was 88%.

Further, ten sheets were passed through the above-mentioned apparatus, but no deterioration of the image was observed, nor was there any damage or deterioration of the characteristics of the photosensitive layer.

The pressure at the second jug N1 is set to 0. 5Kg/cm''
If the transfer is performed below, the transfer rate will be less than 60%, which is not practical. Moreover, the pressure at the nip part N3 is
The higher the transfer rate, the higher the transfer rate, but 300K
If it exceeds g/crn', paper, which is most commonly used as a transfer material, becomes transparent, produces an undesirable gloss, and shortens the life of the transfer roller.

Furthermore, when transferring and fixing using heat as in known devices, it is necessary to heat the photoreceptor surface to 180 to 250°C. However, according to the above-mentioned device, the required heating temperature of the heating member is at most 110°C.
Therefore, the temperature increase on the surface of the photoreceptor can be suppressed to 40 to 50° C., and the durability of the photoreceptor can be greatly increased.

As can be seen from the figure, the toner image on the transfer roller 3 remains on the heated roller for a relatively long time, so it is sufficiently softened during that time, and the solid black density after transfer is 1. ．． A very high value of 5 was obtained.

In the above examples, polyester was used as the toner, but for example, if polyamide with a glass transition temperature of 50'C1 and a melting point of 130°C is used, the pressure at the nip part N3 is 50 Kg/Cm' and the temperature is about 100°C. By heating, high transfer rates and high fixing properties similar to those of the above device were obtained.

The relative arrangement of the photoreceptor, the transfer roller 2.3, and the pressure/heating member 4 in the above-described embodiment is not limited to that shown in the drawings. It is also possible to appropriately change the direction in which the transfer material enters and discharges by disposing the transfer material 3 or the like on the side of the other parts (in the left-right direction in the figure).

FIGS. 2A and 2B show other embodiments of the present invention, particularly a photoreceptor 1, a transfer roller 2 as a first intermediate transfer member, a transfer roller 3 as a second intermediate transfer member, and a pressurizing member as a pressure heating member. It shows the relative arrangement of the pressure heating roller 4 or members corresponding thereto.

The one shown in FIG. 2A uses rollers 2a and 2b and a belt 2C wound around them instead of the transfer roller 2.

The one in FIG. 2B further includes a transfer roller 3 and a roller 3a.
, 3b and a belt 3c.

It is easy to see that such a device can perform the same function as the one in the above-mentioned embodiment, and that by configuring it in this way, the shape of the entire device and the design and arrangement of the related structures of each member can be changed in various ways. That would be understandable.

(3) Effects of the Invention Since the present invention has the above configuration, the toner is constantly transferred by pressure during the entire process from the formation of the toner image until it is fixed and fixed on the transfer material. , the image is not disturbed by vibrations or the presence of electrolysis, and the toner is not scattered inside the device, making it possible to obtain a high quality image with a high transfer rate. Since it is possible to reduce the pressure as much as possible and also suppress the temperature rise, it is possible to significantly extend the life of the photoreceptor, which has the effect of stably obtaining high-quality images over a long period of time. .

[Brief explanation of drawings]

FIG. 1 is a side view of an image recording apparatus showing an embodiment of the present invention. FIGS. 2A and 2B show another embodiment of the present invention. FIG. 3 is a schematic diagram showing the relative arrangement of main parts. DESCRIPTION OF SYMBOLS 1...Photoreceptor, 2.3*φ*Transfer roller, 4◆*Q pressure heating roller, 5*Charger charger, 6*Image signal writing means, 7*Developer, 8 .8a, 8b-・, cleaner, 14eΦ・registration roller, 1511 umbrella transport path, N
l, N2, N3/fist/nip part. Figure 1

Claims (1)

[Claims] A traveling photoreceptor with a photosensitive layer formed on its surface, a first intermediate transfer member in pressure contact with the photoreceptor, a second intermediate transfer member in pressure contact with the first intermediate transfer member and having a heat source inside; An image comprising: a pressure heating member that is in pressure contact with a second intermediate transfer member and has a heat source therein; and means for passing a sheet-like transfer material through a pressure contact area between the second intermediate transfer member and the pressure heating member. In the recording apparatus, the contact pressure between the first intermediate transfer body and the second intermediate transfer body is higher than the contact pressure between the photoreceptor and the first intermediate transfer body, and An image recording device in which the pressure is lower than the contact pressure with the pressurized heating body.