JP2619629B2 - Intermediate transfer member cleaning method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning an intermediate transfer member in an electrostatic recording apparatus having an electrostatic latent image carrier, an intermediate transfer member, and a transfer member.

2. Description of the Related Art In an electrophotographic method, a photoconductive layer formed on a conductive substrate is uniformly charged, and then an electrostatic latent image is formed by an exposure operation. This latent image is visualized with toner. The visualized image is transferred to transfer paper such as paper by electrostatic attraction, and then fused and fixed to the transfer paper by a fixing roll. In the transfer process, a corotron or a roll to which a bias is applied is generally used in many cases. However, in many cases, it is known that image disturbances in this transfer step degrade the quality of the final fixed image.

In view of this, for example, as disclosed in Japanese Patent Publication No. 37-11646, the electrostatic transfer step is omitted, the toner image formed directly on the photosensitive material and the transfer paper are superimposed, and the heat transfer is performed. A method of transferring and fixing with a roll or the like, using an intermediate transfer medium formed by silicon rubber or the like described in Japanese Patent Publication No. 46-41679, once the toner image formed on the photoconductor is non-electrostatically Transfer method to transfer the toner image on the intermediate transfer medium to the transfer paper at the same time as fixing the toner image on the intermediate transfer medium by transferring the intermediate transfer medium and the heat roll through the transfer paper, Japanese Patent Publication No. 48-22763. JP-A-56-138742 discloses a thermal transfer fixing method in which a conductive magnetic toner and a silicone rubber intermediate transfer medium are combined.
A thermal transfer fixing method using a charge retaining layer made of a heat-resistant resin and an intermediate transfer medium such as silicon rubber has been proposed.

These traditional technologies start with a simplified process,
Increasingly, the quality of copied images was improved. That is, in a transfer method using an electrostatic force by a corotron or the like, disturbance of a toner image on transfer paper occurs, and in a final fixed image, an image such as disturbance around a line image, a decrease in resolution, and a decrease in granularity of a solid image. In order to reduce the quality, an attempt has been made to avoid these disadvantages by a non-electrostatic transfer method.

The copying method using the intermediate transfer medium employs a non-electrostatic transfer system, so that a superior image quality can be obtained as compared with the method using electrostatic transfer. However, in the case of cleaning the toner image remaining on the intermediate transfer medium, means such as a fur brush, a blade, and a web cannot be used, which has been extremely inconvenient. In other words, any cleaning means can be adopted as long as it is rigid and has a very smooth surface, such as a normal photoreceptor, but the intermediate transfer medium uses a unique material such as silicon rubber. Cleaning was extremely difficult because of the configuration.

As a method of cleaning the surface of the intermediate transfer medium, for example, JP-A-59-78378, JP-A-59-87482 and JP-A-59-133581, a method of using a metal roll and cleaning using a blade Is disclosed.

Problems to be Solved by the Invention However, these methods have good initial creasing properties, but due to the temperature rise of the entire system, etc.
It was very poor in terms of maintenance stability and unstable.

The present invention has been made in view of the above-mentioned drawbacks, and an object of the present invention is to provide a novel cleaning method capable of obtaining good cleaning performance stably over a long period of time. It is another object of the present invention to provide a method of cleaning an intermediate transfer member that improves the reliability of an intermediate transfer member transfer system.

Means for Solving the Problems The present invention relates to a method for cleaning an intermediate transfer member in an electrostatic recording apparatus having an electrostatic latent image carrier, an intermediate transfer member, and a transfer roll, wherein a metal roll having a heat source therein is interposed. When the residual toner on the intermediate transfer member is transferred onto the metal roll by pressing against the transfer member, the melting point of the toner is set to T.
m, when the surface temperature of the metal roll is T1 and the surface temperature of the intermediate transfer member is T2, the surface temperature of the metal roll and the surface temperature of the intermediate transfer member are set so as to satisfy a relationship of T2 <T1 <Tm. Features. The melting point of the toner means a temperature at which the binder resin constituting the toner melts and the toner flows.

In the present invention, in order to set the respective temperatures of T1, T2, and Tm so as to have the above relationship, the cooling device of the intermediate transfer body or the heat source of the metal roll is controlled while detecting the surface temperature of the intermediate transfer body. Do it.

In the present invention, the relationship between T1, T2, and Tm is also affected by the nip pressure and the nip width. Therefore, it is necessary to sufficiently consider the diameter of the metal roll, the pressing force, the hardness of the intermediate transfer member, and the like.

In the present invention, each temperature of T1, T2 and Tm is T2 <T1
It is necessary to satisfy the relationship <Tm. because,
When T1 is higher than Tm, the toner is transferred to the surface of the metal roll in a liquid state, so that scraping by the metal blade becomes impossible, and the temperature of the entire system also increases. Also, T1
If the temperature is lower than T2, the transition to the metal roll does not occur due to the effect of the temperature gradient, or the rate of transition to the metal roll becomes extremely poor.

Operation The operation of the present invention will be described.

FIG. 2 is an image forming process diagram in the electrostatic recording apparatus of FIG. 1 to which the cleaning method of the present invention is applied. The latent image formed on the electrostatic latent image carrier 1 (FIG. 2A) is visualized by the toner 6 (FIG. 2B), and the first intermediate transfer member 21
Then, the toner on the electrostatic latent image carrier 1 is transferred to the first intermediate transfer member 21 by contact with the first intermediate transfer member 21 (FIG. 2c). The transferred toner is transferred onto the second intermediate transfer member 22 by further contacting with the second intermediate transfer member 22 (FIG. 2d). To transfer and fix the toner on the recording paper 3 (FIG. 2e).

In the above process, the toner remains on the first intermediate transfer member. The residual toner 7 is cleaned by pressing the metal roll 5 having a heat source therein against the first intermediate transfer member 21. (FIG. 2f).

In the present invention, when the metal roll is pressed against the first intermediate transfer body, the surface temperature of the metal roll and the surface temperature of the first intermediate transfer body are set so as to satisfy the relationship of T2 <T1 <Tm. As a result, the residual toner is efficiently transferred onto the metal roll.

Examples Next, the present invention will be described with reference to examples.

FIG. 1 is an explanatory diagram illustrating an example of the configuration of an electrostatic recording apparatus to which the cleaning method of the present invention is applied. In this recording apparatus, in order to increase the speed, the intermediate transfer member is composed of a first intermediate transfer member 21 and a second intermediate transfer member.
22 and two. On the latent image carrier 1 charged by the charger 9, a latent image is formed by the image exposure device 10, and then a toner image is formed by the developing device 8. Reference numeral 11 denotes a cleaning blade. The formed toner image is transferred onto the first intermediate transfer member by bringing the latent image carrier 1 into contact with the first intermediate transfer member 21.
The toner image 6 on the first intermediate transfer member is transferred onto the second intermediate transfer member by bringing the first intermediate transfer member 21 into contact with the second intermediate transfer member 22 having the heat source 12 therein. The transferred toner image is transferred and fixed onto the recording paper 3 by the pressing roller 4.

The toner remaining on the first intermediate transfer member is internally supplied with a heat source 13
The cleaning is performed by pressing the metal roll 5 having the following structure against the first intermediate transfer member 21. That is, when a metal roll having a surface temperature T1 lower than the melting point of the toner but higher than the surface temperature T2 of the first intermediate transfer member is pressed against the first intermediate transfer member, the residual toner particles are reduced due to the temperature gradient. The first intermediate transfer member is efficiently transferred onto the roll, and the first intermediate transfer member is cleaned. The toner 7 transferred onto the metal roll is
Is scraped by

FIG. 3 is an explanatory diagram illustrating another example of the configuration of the electrostatic recording device to which the cleaning of the present invention is applied.

In the electrostatic recording apparatus shown in this drawing, the intermediate transfer body is configured to directly contact the transfer paper. That is,
The toner image 6 on the intermediate transfer body is transferred and fixed onto the transfer paper by bringing the intermediate transfer body 2 into pressure contact with a pressure roller 4 having a heat source 12 therein via a transfer paper 3.

The toner remaining on the intermediate transfer member is cleaned by pressing a metal roll 5 having a heat source 13 therein against the intermediate transfer member as in the case shown in FIG. Is scraped off by the blade 14.

In the present invention, each temperature of T1, T2 and Tm is T2 <T1 <
It is necessary to satisfy the relationship Tm. Since the metal roll has a heat source inside, its surface temperature is kept constant over the entire peripheral surface, while the surface temperature of the intermediate transfer body varies in various ways on the peripheral surface, In short, when the residual toner transfers to the metal roll, T1,
It is only necessary that T2 and Tm satisfy the above relationship.

The surface temperature of the intermediate transfer member is controlled so as to satisfy the above relationship.As a cooling unit for control, for example,
Attach fins for heat radiation inside the intermediate transfer body, make the intermediate transfer body a belt shape, make the intermediate transfer body a roll with a large outer diameter, or control the temperature with a fan while detecting the surface temperature of the intermediate transfer body And the like.

In the electrostatic recording apparatus to which the present invention is applied, the intermediate transfer bodies 2, 21 and 22 are, for example, based on points such as a transfer rate in primary transfer and secondary transfer, omission of an image portion, and cleaning properties of the intermediate transfer medium. It is preferable that the frequency of the unevenness is 2 cycles / mm or less and the depth is 3 μm or less. As a material having such a surface having smoothness, for example, a material having a surface layer made of an elastomer or a rubber material formed on an aluminum substrate may be mentioned. Materials that can be used include, for example, TSE387RTV, TSE388W, TSE389C (trade name) manufactured by Toshiba Silicone Co., Ltd.,
KR271, KR272, KE130, KE136-V, KE manufactured by Shin-Etsu Chemical Co., Ltd.
12RTV, KE17RTV, KE42RTV, KE113RTV, KE1800ABCRTV, etc. (all trade names), SH-780, SE9 manufactured by Toray Silicone Co., Ltd.
14C, SH850, SH748V, SRX475V, SH1603V, etc. (trade name), Bayer's EVW-1018, EV-1840, etc. (trade name), Nippon Polyurethane Co., Coronate C-40
46, Nyaporan 4038, etc. (above trade names). Further, carbon black and metal powder may be dispersed for the purpose of preventing static electricity.

The material of the metal roll 5 is aluminum, SUS,
A relatively hard material such as brass, iron, and phosphor bronze is used. Alternatively, as a material of the blade 14 for scraping the toner transferred onto the metal roller, phosphor bronze, stainless steel for a spring material, or the like is used.

Next, the present invention will be described based on specific operating conditions.

The operation was performed at an ambient temperature of 25 ° C. using an electrostatic recording apparatus having the configuration shown in FIG. The first intermediate transfer member is a roll having a 0.5 mm thick silicone rubber layer on an A1 substrate having a diameter of 120 mm and a thickness of 4 mm, and a melting point of 120 ° C. as a developer.
The operation was performed under the conditions of a surface speed of the photoreceptor of 500 mm / sec using the styrene / acrylate-based toner. The surface temperature of the second intermediate transfer member was set at 150 ° C. The surface temperature T2 of the first intermediate and the surface temperature T1 of the metal roll, respectively
When the cleaning operation was performed at 70 ° C. and 100 ° C., the transferability of the toner from the first intermediate transfer member to the metal roll was good for a long time. Was also good. Therefore, the cleaning performance when operated for a long time was excellent.

When the cleaning operation was performed under the same conditions as above except that T1 and T2 were set to 80 ° C. and 150 ° C. for comparison, the transferability of the toner from the first intermediate transfer body to the metal roll was low, Residual toner was generated on the first intermediate transfer member, and therefore, when operated for a long time, the cleaning performance of the first intermediate transfer member was poor.

Further, the cleaning operation was performed under the same conditions as above except that T1 and T2 were set to 150 ° C. and the surface temperature of the second intermediate transfer member was set to 200 ° C.
The transferability of the toner from the intermediate to the metal roll was insufficient, and the toner transferred on the metal roll was also in a molten state on the metal roll and could not be sufficiently scraped off by the blade.

When T1 and T2 are set to 80 ° C and 85 ° C, respectively, when set to 85 ° C and 95 ° C, and when set to 150 ° C and 70 ° C, respectively, other conditions are the same as above. When the cleaning operation was performed, residual toner was generated on the first intermediate transfer member, and the cleaning performance was poor.

Effect of the Invention As described above, in the present invention, when the residual toner on the intermediate transfer body is transferred to the metal roll,
Since a metal roll having a heat source inside was used and the surface temperature and the surface temperature of the intermediate transfer member were set so as to satisfy the above-described relationship, as apparent from the above comparison, the toner remaining on the intermediate transfer member Is effectively cleaned,
It shows stable cleaning performance even for long-time operation.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of the configuration of an electrostatic recording apparatus to which the cleaning method of the present invention is applied, and FIG.
FIG. 3 is an image forming process diagram in the electrostatic recording device of FIG. 1;
FIG. 3 is an explanatory diagram showing another example of the configuration of the electrostatic recording device to which the cleaning method of the present invention is applied. 1 .... electrostatic latent image carrier (photoreceptor), 2 .... intermediate transfer body,
3 ... Transfer paper, 4 ... Press roll, 5 ... Metal roll,
6: toner image, 7: residual toner, 8: developing device, 9
... Charger, 10 Exposure device, 11 Cleaning blade, 12, 13 Heat source, 14 Blade, 21 First intermediate transfer member, 22 Second intermediate transfer member.

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Koichi Saito 2274 Hongo, Ebina-shi Fuji Xerox Co., Ltd. Person Toru Okamoto 2274 Hongo, Ebina Fuji Xerox Co., Ltd. Ebina Works (56) References JP-A-57-4081 (JP, A)

Claims (2)

(57) [Claims] In a method of cleaning an intermediate transfer member in an electrostatic recording apparatus having an electrostatic latent image carrier, an intermediate transfer member, and a transfer member, a metal roll having a heat source therein is pressed against the intermediate transfer member, When transferring the residual toner on the intermediate transfer member onto the metal roll, the melting point of the toner is Tm,
T1 for the surface temperature of the metal roll and T2 for the surface temperature of the intermediate transfer member
Wherein the surface temperature of the metal roll and the surface temperature of the intermediate transfer member are set so as to satisfy the relationship of T2 <T1 <Tm. 2. An intermediate transfer member comprising a first intermediate transfer member and a second intermediate transfer member.
Claim 1 comprising pressing the intermediate transfer member against the intermediate transfer member.
6. The method for cleaning an intermediate transfer member according to item 4.