JPH04104182A - Fixing device for image forming device - Google Patents

Abstract

PURPOSE:To maintain excellent fixing strength by driving a cooling means according to cooling means driving information, and cooling the parts where an image carrier goes not pass, of both end parts of a heating roller. CONSTITUTION:While the image carrier 4 fed to this fixing device is inserted and held between the heating roller 1 and a pressure roller 3 and carried in the direction of the C, a developer whose surface has the formation of a visual image is melted and infiltrated into the image carrier 4, with heat energy from a halogen lamp 2 whose calorific value is controlled and the pressure of the roller 3, to obtain the completion of fixing. An image carrier recognizing means 7 recognizes the information of the carrier 4, and sends an image carrier type recognizing signal (a) to a cooling fan control means 6. The cooling fan control means 6 receiving the signal (a) selects corresponding information from cooling fan driving information, to send a cooling fan driving signal (b) to a cooling fan 5, drives the fan 5 to cool only both end parts of the roller 1, and controls a temp. distribution. Thus, stable excellent fixing strength can be always maintained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a fixing device for an image forming apparatus.

[Conventional technology]

The fixing device of an image forming apparatus consists of a heat generating means such as a halogen lamp, a thin cylindrical heating roller made of metal such as aluminum, and a heating roller that is made of aluminum or other metal. The image bearing member, such as a sheet of paper, is sandwiched between the pair of rollers and conveyed while being heated and pressurized, thereby fixing a visible image. Conventionally, in order to stably achieve good fixing strength, the temperature on the surface of a heating roller has been monitored and the amount of heat generated by a halogen lamp has been controlled so as to always maintain the temperature within a predetermined range.

[Problem to be solved by the invention]

The fixing device of the conventional image forming apparatus described above simply changes the amount of heat generated by the halogen lamp in order to control the surface temperature of the heating roller. When such an image bearing member is continuously passed through, there is a drawback that only the central portion of the heating roller receives heat from the passing image bearing member, resulting in a decrease in temperature and failure to maintain good fixing strength. In order to correct this, if the heat output of the halogen lamp is increased, the parts at both ends of the heating roller where the image carrier does not pass will overheat and become abnormally high temperature.
This may cause a fatal accident such as damage to the parts that make up the image forming apparatus.

An object of the present invention is to provide a fixing device for an image forming apparatus that does not have the above-mentioned drawbacks and can maintain good fixing strength regardless of the size and thickness of an image carrier.

[Means to solve the problem]

The fixing device of the image forming apparatus of the present invention includes a heat generating means such as a halogen lamp, a thin cylindrical heating roller incorporating the heat generating means, and a heating roller that rotates together with the heating roller while being in contact with the heating roller under a predetermined pressure. In a fixing device of an image forming apparatus, which includes a pressure roller and fixes a visible image by passing an image carrier such as paper between the heating roller and the pressure roller, both end portions of the heating roller are cooled. a recognition means for recognizing the type of the image bearing member and the number of continuously fed sheets; and a cooling means for recognizing the type of the image bearing member and the number of continuously fed sheets using a predetermined method according to the recognized type of the image bearing member and the number of continuously fed sheets. The cooling I control means controls the cooling capacity of the cooling I control means.

〔Example〕

Next, the fruits of this invention! ! An example will be explained with reference to the drawings.

FIG. 1 is a perspective view of one embodiment of the present invention.

A thin cylindrical heating roller l made of aluminum or the like is equipped with a halogen lamp 2 serving as a heating means. A pressure roller 3, which has a metal shaft made of stainless steel or the like coated with silicone rubber or the like, is in contact with the heating roller 1 with a predetermined pressure. The heating roller 1 is rotationally driven in the direction of arrow A by a drive mechanism (not shown), and the pressure roller 3 is accordingly rotated together with the heating roller 1 in the direction of arrow B.

At both ends of the heating roller 1, two cooling fans 5, which are cooling means, are arranged, one each on an extension line of the rotation axis of the heating roller 1. The cooling fans 5 are each connected to a cooling fan control means 6, and the cooling fan control means 6 is connected to an image carrier type recognition means 7 that detects information regarding the type of paper used and the number of continuous sheets fed.

Next, the operation will be explained step by step.

The image carrier (paper) 4 is fed one by one to an image forming means (not shown) by an image carrier feeding means (not shown), and a visible image is formed on the surface thereof using a developer such as toner. After that, it is fed to the fixing device. The image carrier 4 fed to the fixing device is sandwiched between the heating roller 1 and the pressure roller 3 and conveyed in the direction of arrow C, while the surface temperature of the heating roller 1 is controlled by a heat generation amount control means (not shown). The heat energy from the halogen lamp 2 whose calorific value is controlled within a predetermined range and the pressure of the pressure roller 3 which is pressed against the heating roller 1 by a biasing means such as a spring (not shown) is used. , the developer forming the visible image on its surface melts and penetrates, completing the fixing.

The image carrier recognition means 7 recognizes information such as the external dimensions, thickness, material, and number of continuously fed image carriers 4 that are fed one by one by an image carrier feeding means (not shown), and The carrier type recognition signal a is transmitted to the cooling fan control means 6. The cooling fan iiiIIw unit 6 that has received the image carrier type recognition signal a is a cooling fan that is predetermined and stored in accordance with the types of image carriers used in the image forming apparatus, the number of sheets to be fed, etc. Applicable information is selected from the drive information, and a cooling fan drive signal is sent to the cooling fan 5, and the cooling fan 5 is driven to cool only both ends of the heating roller l to control the temperature distribution.

At this time, the cooling fan IIIg! The cooling fan drive information stored in the means 6 is as follows: (1) Regarding the external dimensions of the image carrier to be fed, narrower image carriers have more cooling capacity; ■ Regarding the thickness: (3) Regarding the number of continuous sheets fed, decide through experiments or simulations so that the cooling capacity increases as the cumulative number of sheets continuously fed increases. Bye.

Note that the image carrier type recognition means 7 only needs to be able to detect the type of image carrier used and the number of continuously fed sheets, and the method thereof is not particularly limited. The number of continuously fed sheets may be counted by a counter, or a command from a host device such as a computer may be input, or the width and thickness of the paper may be detected by a sensor.

〔Effect of the invention〕

As described in detail above, according to the present invention, there is provided a cooling means for cooling both end portions of the heating roller, a recognition means for recognizing the type of image carrier, and a cooling means for cooling the cooling means based on information about the recognized image carrier. The cooling means is driven in accordance with predetermined cooling means drive information corresponding to the type of image bearing member and the number of sheets continuously fed, and the heating roller is prevented from passing through the image bearing member at both ends of the heating roller. Since this section is cooled, even when a narrow, thick image carrier such as an envelope is continuously passed through, it is possible to maintain stable and good fixing strength without causing an abnormal temperature rise due to overripeness. be.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the present invention. 1... Heat roller, 2... Halogen lamp, 3... Pressure roller, 4... Image carrier, 5... Cooling Fan, 6...Cooling fan control means, 7...Image carrier type recognition means'.

Claims (1)

[Claims] It is equipped with a heat generating means such as a halogen lamp, a thin cylindrical heating roller containing the heat generating means, and a pressure roller that rotates together with the heating roller while contacting it with a predetermined pressure. A fixing device of an image forming apparatus that fixes a visible image by passing a carrier between the heating roller and the pressure roller, a cooling means for cooling both end portions of the heating roller, and a type of the image carrier. and a recognition means for recognizing the number of continuously fed sheets, and a cooling control means for controlling the cooling capacity of the cooling means according to a predetermined method according to the recognized type of image carrier and information on the number of continuously fed sheets. A fixing device for an image forming apparatus, characterized in that: