JPH08685Y2 - Image recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention records a toner image formed on an image carrier such as an electrophotographic copying machine or printer on a transfer material via an intermediate transfer body. The present invention relates to an image recording device.

[Prior Art] Electrophotographic photoreceptors that form electrostatic latent images by charging and exposure, dielectrics that form electrostatic latent images by ion flow, and magnetic recording bodies that form magnetic latent images by magnetic heads. Powder toner is made to adhere according to the latent image pattern of the image carrier to make it visible, this toner image is transferred to a transfer material, and the transfer material is passed through a fixing section to fix the toner image on the transfer material. The image recording apparatus having such a configuration has been widely put into practical use.

As a transfer method in such an image recording apparatus, various methods such as a method using an electrostatic force, a method using a magnetic force, a method using an adhesive force, and a method using a solvent have been proposed, but they are widely used at present. There is a method that uses electrostatic force.

Corona discharge transfer method and bias roll method are well known as transfer methods using this electrostatic force.

Among them, the corona discharge transfer method is a method in which a charge having a polarity opposite to that of the toner is applied to the back surface of the transfer material by corona discharge to form a transfer electric field to transfer the toner image to the transfer material by electrostatic force.

However, with this corona discharge transfer method, there is a limit to the amount of toner that can be transferred to the transfer material (transfer efficiency of 80% to 90%).
However, the image density was not reduced. In particular, the image density is remarkably reduced in an environment of high temperature and high humidity. Further, since the toner is electrostatically moved, it is difficult to prevent the toner from scattering, which may impair the sharpness of the image or stain the inside of the apparatus. Furthermore, in this type of transfer method using electrostatic force, the conductive toner cannot be transferred, and the charge given to the back surface of the transfer material by corona discharge is injected into the conductive toner through the transfer material and retransferred to the surface of the image carrier. The current situation is that satisfactory images cannot be obtained due to the occurrence of scattering and scattering.

Conductive toner is indispensable for speeding up and high image quality of the device as well as reduction in size of the developing section, and it is considered that the use of conductive toner will become more important in the future, so improvement of the transfer method is urgent. It is about to be done.

These problems are common to the transfer method using electrostatic force, and the same can be said for the bias roll method.

As a transfer method for solving these problems, the toner image on the image carrier is pressed and transferred to an intermediate transfer member having a rubber as a transfer layer, and the transferred toner image is heated by using a heating roll to melt the toner image. There has been proposed a method of press-transferring and fixing (transfer fixing) onto a transfer material (for example, Japanese Patent Publication No. 46-
41679, Japanese Patent Publication No. Sho 48-22763, Japanese Patent Laid-Open No. Sho 49-7855.
No. 9, and US Pat. No. 3,993,825).

In such a method, on the one hand, on the surface of a rubber-based transfer layer such as silicone rubber, which has the releasability to the molten toner, and on the other hand, the property of adhering fine particles such as powder toner when pressed. First, the powder toner image is pressed and transferred, and the toner image on this transfer layer is brought into contact with a heating member such as a heating roll to be heated and melted, and at the same time, the melted toner is pressed and transferred onto the transfer sheet to be fixed. To do.
That is, since the toner image melted by heating is easily transferred and fixed on the transfer sheet based on the releasability of the transfer layer, there is no reduction in the resolution of the toner image due to the transfer process.
Moreover, the transfer is performed at a high transfer rate and is not affected by the environment such as high humidity.

However, in this method, since a heating source such as a heating roll is disposed in the vicinity of the image bearing member, the temperature of the image bearing member rises due to the heat of the heating source, which significantly affects the latent image forming characteristics and reduces the sensitivity. Deterioration and fogging are likely to occur. Therefore, it is necessary to provide some kind of cooling means on the intermediate transfer body that is brought into pressure contact with the image carrier, resulting in an increase in size of the apparatus.

[Problems to be Solved by the Invention] In order to solve the above problems, an image recording apparatus having a structure in which transfer and fixing are performed via the following two intermediate transfer bodies has been proposed. That is, the surface of the first intermediate transfer member is made of silicone rubber or the like and is in pressure contact with the image carrier, and the surface is also made of silicone rubber or the like, and a heating source such as a lamp heater is provided inside the first intermediate transfer member. The second to be pressed
A toner on the image carrier, which has an intermediate transfer member and a pressure member that is in pressure contact with the second intermediate transfer member, and allows the transfer material to pass between the second intermediate transfer member and the pressure member. Is sequentially transferred to the first intermediate transfer member, the second intermediate transfer member, and the transfer material to perform fixing. With such a configuration, it is possible to avoid the influence of the heat of the heating source on the image carrier and to fix the toner image with low power consumption, and thus the temperature rise on the surface of the image carrier is suppressed, The life can be extended and good image quality can be maintained.

However, in the apparatus having such a configuration, since the elastic body is used as the material of the first intermediate transfer body, the second intermediate transfer body, and the pressure body, the expansion and contraction and transfer of the image by the pressure contact force at each transfer unit. It had the drawback of causing a reduction in efficiency.

Therefore, an object of the present invention is to reduce the power consumption and increase the temperature of the image carrier while taking advantage of the characteristics of the above-mentioned intermediate transfer system that utilizes the adhesiveness of the silicone rubber material to the powder toner and the releasability to the molten toner. It is an object of the present invention to provide an image recording apparatus capable of obtaining a good recorded image having a high image density without suppressing the expansion and contraction of the image.

[Means for Solving the Problems] The present invention is directed to an image carrier and the image carrier pressed against the image carrier.
A first intermediate transfer member having a surface layer made of an elastomer or a rubber material, and a second intermediate transfer member having a surface layer made of an elastomer or a rubber material and being in pressure contact with the first intermediate transfer member and having a heating source therein. And a pressurizing member that is in pressure contact with the second intermediate transfer member, and a transfer material is passed between the second intermediate transfer member and the pressurizing member to form a latent image formed on the image carrier. An image in which toner images developed according to a pattern are sequentially transferred onto the first intermediate transfer member by the first transfer, transferred onto the second intermediate transfer member by the second transfer, and transferred onto the transfer material by the third transfer. In the recording apparatus, the pressure contact force between the image carrier and the first intermediate transfer member is P ₁ , the pressure contact force between the first intermediate transfer member and the second intermediate transfer member is P ₂ , and the second intermediate transfer member is When the pressure contact force between the pressure body and the pressure body is P ₃ , P ₁ <P ₃
<P ₂ , the surface strain amounts Δl ₁ and Δl _{2 of} the first intermediate transfer member in the first transfer and the second transfer are equal, and the second transfer in the second transfer and the third transfer are the same.
The image recording apparatus is characterized in that the surface strain amounts Δm ₁ and Δm _{2 of the} intermediate transfer member are set to be equal to each other.

In the present invention, the amount of surface strain Δl ₁ , Δl ₂ , Δm ₁ , Δ
The m ₂ is the amount of “elongation” that the silicone rubber, which is each surface layer of the first intermediate transfer member and the second intermediate transfer member, causes at each transfer nip portion due to the pressure applied at each transfer.

The amount of this "elongation" that occurs at each transfer nip portion depends on the hardness of the first intermediate transfer body, the second intermediate transfer body and the pressure body, the diameter of the roll, the pressing force, etc. Is measured as follows.

For example, in order to measure the strain amount Δl ₁ of the first intermediate transfer body at the first transfer portion, as shown in FIG. 1A, an appropriate ink material ( (Liquid) is attached and marked, and the paper 10 is passed through the first transfer portion while rotating the photosensitive body 2 and the first intermediate transfer body 4 which are under pressure. At least one first intermediate 4
By rotating more than one rotation, two or more of the ink traces are transferred to the paper (FIGS. 1 (b) and (c)). First
Distance l ₁ (FIG. 1 (b)) of the two ink traces 11 when the strain of the intermediate transfer member and without ink traces 11 when the strain is present '
The difference Δl ₁ from the value of ₁ (1) in FIG. 1 (c) is defined as the amount of strain.

State that the strain is not at all, because it is the absence pressure between the photosensitive member and the first intermediate transfer member, l _1, by measuring the outer diameter d of the first intermediate transfer member, l ₁ = [pi] d Given in.

The amount of strain Δl ₁ is Δl ₁ = l ′ ₁ −l ₁ = l′−πd. Similarly, the strain amount Δl ₂ of the first intermediate transfer member at the second transfer portion can be measured by passing a sheet to which the ink is transferred through the second transfer portion.

In the present invention, the surface strain amounts of the first intermediate transfer member in the first transfer portion and the second transfer portion, which are measured as described above, are made equal, and in the second transfer portion and the third transfer portion, respectively. The pressing force at each transfer portion is set so that the strain amounts of the second intermediate transfer member are equal to each other.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

FIG. 2 is a schematic diagram of an electrostatic recording device to which the present invention is applied. In this apparatus, the electrostatic latent image forming unit 1 forms an electrostatic latent image pattern on the photoconductor 2 having a photoconductive layer on the surface thereof. The photoconductor 2 is rotated in the direction of arrow A by a drive source (not shown), and the electrostatic latent image pattern on the surface reaches the developing unit 3. In the developing unit 3, the electrostatic latent image pattern is developed with toner. Magnetic or non-magnetic toner is used as the toner.For example, in the case of magnetic-component toner, the magnetic-component toner 3b is erected on the sleeve 3a by the magnet provided in the developing sleeve 3a, and is exposed. It rotates toward the body 2 and is regulated to a constant height by the spike regulation member 3c on the way. The toner 3b is conductive (volume resistance is 10 ¹² Ωcm or less), and according to the electrostatic latent image pattern on the photoconductor 2, a reverse charge is induced at the tip of the brush, which is the toner chain, and the toner particles are electrostatic latent images. A toner image is formed by successively moving to the latent image side in proportion to the amount of charge of the image. The toner image thus formed is transferred by pressure onto the first intermediate transfer body 4, which is in pressure contact with the photoconductor 2. First intermediate transfer member 4
Is formed by coating the surface of the metal roll 42 with silicone rubber 41, and is rotated by being pressed against the photoconductor 2 by a pressing means (not shown). The toner image on the first intermediate transfer member 4 is pressed against the second intermediate transfer member 5 having a lamp heater (not shown) therein, so that the toner image on the first intermediate transfer member 4 is transferred from the first intermediate transfer member 4 to the second intermediate transfer member 4. 5 is transferred by pressing. Similar to the first intermediate transfer body 4, the second intermediate transfer body 5 is obtained by coating the surface of the metal roll 42 with the silicone rubber 41, and is pressed against the first intermediate transfer body 4 by a pressing means (not shown). Followed rotation. The toner image on the second intermediate transfer member 5 is gradually melted by the heat of the lamp heater inside the transfer member 5, and the transfer paper 7
It completely melts at the transfer part. In this state, the silicone rubber on the surface of the second intermediate transfer member 5 is
The toner image is released, and the toner image is transferred and fixed on the transfer paper 7 that passes between the transfer body 5 and the pressure body 6 pressed by the transfer body 5. The photoconductor 2 on which the toner image is transferred to the first intermediate transfer body 4 is neutralized by the neutralization unit 8 and a slight amount of the residual toner is removed by the cleaning blade 9a in the cleaning device 9 to be used in the next process.

FIG. 3 is a schematic enlarged view of the fused portion of the photoconductor 2 and the first intermediate transfer member 4, that is, the first transfer portion B in the above-mentioned apparatus. Here, FIG. 3A shows a state in which the pressure contact is released and the photosensitive member 2 and the first intermediate transfer member 4 are separated from each other in a state before transfer, and FIG. 3B shows a transfer state. In this state, the photoconductor 2 and the first intermediate transfer body 4 are in pressure contact with each other by a pressure contact unit (not shown). Here, the first intermediate transfer member 4 in FIG. 3B is considered to follow hook elasticity, and the amount of deformation is proportional to the pressure contact force, and deformation occurs in the direction of the pressure contact force. However, the amount of surface strain which is a problem in the present invention is the strain generated in the direction parallel to the first intermediate transfer member 4 by the deformation in the direction of the pressure contact force, that is, in the direction indicated by E in the figure. This is the amount of strain, which is secondarily generated with respect to the pressure contact. The strain in the E direction naturally occurs as "elongation", but this amount is determined by the hardness, thickness and shape of the silicone rubber layer on the surface of the first intermediate transfer member 4. Therefore, the toner image on the photosensitive member 2 is adhesively transferred at the first transfer portion B onto the first intermediate transfer member 4 which extends by Δl _{1 in the} direction E in the figure by pressure contact. Next, the toner image on the first intermediate transfer member 4 passes through the first transfer portion B and heads toward the second transfer portion C, but the first contact portion B releases the pressure contact force, so that the first intermediate transfer member 4 is released. The surface strain of the body 4 disappears and Δl ₁ = 0, so that the toner image apparently shrinks. Therefore, in the second transfer portion C, the pressing force is applied so as to generate the strain in the E direction so that the strain is the same as that of the first intermediate transfer member 4 generated in the first transfer portion B, that is, Δl ₁ = Δl _2. Need to control.

In addition, regarding the second intermediate transfer member, the second transfer portion C and the third
It is necessary to control the pressing force so that the strain amounts Δm ₁ and Δm ₂ in the transfer portion D become equal.

The present invention focuses on this point, and the pressure contact force between the image carrier and the first intermediate transfer member is adjusted so that the amount of strain in each transfer portion of the first intermediate transfer member and the second intermediate transfer member becomes equal. When P ₁ , the pressure contact force between the first intermediate transfer member and the second intermediate transfer member is P ₂ , and the pressure contact force between the second intermediate transfer member and the pressure member is P ₃ , P ₁ <P _The pressure contact force is set as ₃ <P _{2 so} that the expansion / contraction of the intermediate transfer member at the transfer portion does not appear as the expansion / contraction of the final image.

[Embodiment] Hereinafter, the present invention will be described in detail with reference to the drawings.

In FIG. 1, as the first intermediate transfer body 4 and the second intermediate transfer body 5, those in which a surface layer made of an elastomer or a rubber material is formed on a metal roll such as Al are used. Examples of usable materials include TSE387RTV, TSE388W, TSE389C (above trade name) manufactured by Toshiba Silicone Co., Ltd., KR271, KR272, KE130, KE136-V, KE12RTV, KE1 manufactured by Shin-Etsu Chemical Co., Ltd.
7RTV, KE42RTV, KE113RTV, KE1800ABCRTV, etc. (above product name)
SH-780, SE914C, SH850, SH748V, manufactured by Toray Silicone Co., Ltd.
EVX manufactured by Bayer, such as SRX475V, SH1603V (these product names)
-1018, EV-1840, etc. (these product names), Coronate C-4046, Niapolan 4038, etc. (these product names) manufactured by Nippon Polyurethane Co., Ltd. Carbon black or metal powder may be dispersed in these materials for the purpose of preventing static electricity.

The elastomer or rubber material has a hardness of 30 ° C (JI
S) was applied to a metal roll having an outer diameter of 120 mm to a thickness of 2 mm, and this was used as a first intermediate transfer member. The same material as this was applied to a metal roll having an outer diameter of 50 mm and a thickness of 2 mm to obtain a second intermediate. A metal roll having an outer diameter of 50 mm was used as the pressing body.

The first intermediate transfer member, the second intermediate transfer member, and the pressure member are arranged as shown in FIG. 1, and the toner image formed on the Se-based photosensitive member having an outer diameter of 240 mm is printed on the paper under the following conditions. Transferred and fixed.

Toner: For Fuji Xerox Fx2700 Second intermediate surface temperature: 150 ° C. Process speed: 100 mm / sec At this time, the surface strain amount Δl ₁ , Δl at each transfer portion of the first intermediate transfer body and the second intermediate transfer body _The table below shows ₂ , ₂ , Δm ₁ , Δm ₂ and the magnification of the final image on the paper with respect to the toner image on the photoconductor.

As shown in the table above, with the combination of No. 1 and No. 2 pressure contact forces, a good image without expansion and contraction was obtained, but in No. 3, the image shrinks and in No. 4, it expands. It was

[Effect of the Invention] As described above, in the present invention, the pressure contact force between the image bearing member and the first intermediate transfer member is P ₁ , and the pressure contact force between the first intermediate transfer member and the second intermediate transfer member is P. _{2. When} the pressure contact force between the second intermediate transfer member and the pressure member is P ₃ , P ₁ <P ₃ <P ₂ and the strain amount of the first intermediate transfer member at the first transfer portion and the second transfer portion Δ
l ₁ and Δl ₂ and the strain amounts Δm ₁ and Δm ₂ of the second intermediate transfer member at the second transfer portion and the third transfer portion are respectively Δl ₁ = Δl ₂ and Δm ₁ =
Since the pressure contact force is set to Δm ₂ , it is possible to obtain a good recorded image without expansion and contraction of the image.

[Brief description of drawings]

FIGS. 1 (a), (b), and (c) are explanatory views of strain amount measurement of an intermediate transfer member in a transfer portion, and FIG. 2 is a schematic side view showing a configuration of an electrostatic recording device to which the present invention is applied. 3 (a) and 3 (b) are enlarged schematic views of the first transfer portion in the electrostatic recording apparatus of FIG. 2, where (a) is a state before transfer and (b) is a state during transfer. Represents Reference numerals in the figure: 1 ... electrostatic latent image forming portion; 2 ... photoconductor; 3 ... developing portion; 3a ... developing sleeve; 3b ... magnetic toner; 3c ... regulating member; 4 ... first intermediate transfer body; 41 ... silicone rubber Layers; 42 ... Metal rolls; 5 ... Second intermediate transfer body; 6 ... Pressurizing body; 7 ... Transfer paper; 8 ... Static elimination section; 9 ... Cleaning section; 10 ... Paper; 11 ... Ink; 11 ′ ... Ink marks; A ... Rotation direction; B ... First transfer portion; C ... Second transfer portion; D ... Third transfer portion; E ... Strain direction.

Claims (1)

[Scope of utility model registration request] 1. An image bearing member, which is pressed against the image bearing member,
A first intermediate transfer member having a surface layer made of an elastomer or a rubber material, and a second intermediate transfer member having a surface layer made of an elastomer or a rubber material in pressure contact with the first intermediate transfer member and having a heating source therein. And a pressure member that is in pressure contact with the second intermediate transfer member, and a transfer material is passed between the second intermediate transfer member and the pressure member to form a latent image formed on the image carrier. The toner images developed according to the image pattern are sequentially transferred onto the first intermediate transfer member by the first transfer, transferred onto the second intermediate transfer member by the second transfer, and transferred onto the transfer material by the third transfer. In the image recording apparatus, the pressure contact force between the image carrier and the first intermediate transfer member is P ₁ , the pressure contact force between the first intermediate transfer member and the second intermediate transfer member is P ₂ , and the second intermediate transfer member is When the pressure contact force between the body and the pressure body is P ₃ , P ₁ <P ₃
<P ₂ , the surface strain amounts Δl ₁ and Δl _{2 of} the first intermediate transfer member in the first transfer and the second transfer are equal, and the second transfer in the second transfer and the third transfer are the same.
An image recording device characterized in that the surface strain amounts Δm ₁ and Δm _{2 of the} intermediate transfer member are set to be equal.