BACKGROUND

The present disclosure is directed to a heat fixing device, an electrophotographic image forming apparatus, and a laminated structural body.

DESCRIPTION OF THE RELATED ART

Diamond-like carbon (DLC) is widely used as a surface coating of a sliding member because of its abrasion resistance characteristics. The DLC is used also in a sliding member in an electrophotographic image forming apparatus, such as a copying machine or a printer.

In Japanese Patent Application Laid-Open No. 2015-34980, there is a disclosure of a fixing device including a rotatable first member to be heated by a heat source, a rotatable second member configured to form a nip portion that allows a recording material to be sandwiched between the first member and the second member, and a pressure member which is arranged in the first member, has a contact surface with respect to an inner surface of the first member, and is configured to pressurize the first member against the second member. The pressure member has a surface layer forming a contact surface with respect to the inner surface of the first member, which is formed of a particular diamond-like carbon film (hereinafter sometimes referred to as “DLC film”).

According to the investigations made by the inventors, in the case where irregularities of a surface of a base material for forming the pressure member arranged so as to be in contact with an inner peripheral surface of the first member on a side opposed to the DLC film are large, when the pressure member is used as a heating member, the thermal contact between an inner peripheral surface of a fixing belt and a surface layer of a heater may be deteriorated to decrease the thermal conductivity of heat of the heater to the first member.

Meanwhile, when the surface of the base material on a side facing the DLC film is smoothened, the contact area between the DLC film and the base material is reduced, and hence the adhesiveness of the DLC film to the base material is decreased. As a result, during the use of the fixing device, the DLC film peels off from the base material, and the slidability between the first member and the pressure member may be decreased. The decrease in slidability between the first member and the pressure member causes the occurrence of abnormal noise or poor fixing. In view of the foregoing, the inventors have recognized that it is required to develop a technology enabling improvement of the adhesiveness of the DLC film to the base material without depending on the roughness of a DLC film formation surface of the base material.

SUMMARY

One aspect of the present disclosure is directed to providing a heat fixing device, which is excellent in heat transferability to a first member and can exhibit stable heat fixing performance over a long period of time. In addition, another aspect of the present disclosure is directed to providing an electrophotographic image forming apparatus capable of stably forming a high-quality electrophotographic image. Further, another aspect of the present disclosure is directed to providing a laminated structural body excellent in adhesiveness of a DLC film regardless of the smoothness of a base material serving as an adherend surface.

According to one aspect of the present disclosure, there is provided a heat fixing device comprising: a first member which is rotatable; a heater configured to heat the first member; and a second member which is rotatable, and is configured to form a nip portion that allows a recording material to be sandwiched between the first member and the second member, wherein the heater includes a base material, an intermediate layer on the base material, and a surface layer on the intermediate layer, the surface layer constituting a surface configured to slide on an inner peripheral surface of the first member, the base material contains at least one compound selected from the group consisting of aluminum nitride, aluminum oxide, and silicon nitride, the surface layer includes a diamond-like carbon film, and the intermediate layer contains silicon carbide, and when defining a number of silicon atom in the intermediate layer as (Si), a number of carbon atom in the intermediate layer as (C), and a total number of all elements excluding hydrogen atom in the intermediate layer as (A), a ratio of [(Si)+(C)]/A is 0.8 or more, and a ratio of (Si)/(C) is more than 1.

In addition, according to another aspect of the present disclosure, there is provided an electrophotographic image forming apparatus including a heat fixing device configured to heat a toner image on a recording material, to thereby fix the toner image onto the recording material, wherein the heat fixing device is the above-mentioned heat fixing device.

In addition, according to another aspect of the present disclosure, there is provided a laminated structural body including a base material, an intermediate layer, and a diamond-like carbon film in the stated order, wherein the base material contains at least one compound selected from the group consisting of aluminum nitride, aluminum oxide, and silicon nitride, wherein the intermediate layer contains silicon carbide, and wherein when defining a number of silicon atom in the intermediate layer as (Si), a number of carbon atom in the intermediate layer as (C), and a number of total elements excluding hydrogen atom in the intermediate layer as (A), a ratio of [(Si)+(C)]/A is 0.8 or more, and a ratio of (Si)/(C) is more than 1.

Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

