Surface protective film, transfer member, image forming apparatus, and method for forming image

1. A surface protective film comprising:

a self-healing urethane resin urethane resin has a restoration ratio of about 80% or more and about 100% or less, the restoration ratio being measured by the following method: a load is applied to the surface protective film up to 0.5 mN at a particular measurement temperature over 15 seconds and held at 0.5 mN for 5 seconds, which provides a maximum displacement (h1); then, the load is decreased to 0.005 mN over 15 seconds and held at 0.005 mN for 1 minute, which provides a displacement (h2); and the restoration ratio is calculated from formula [{(h1−h2)/h1}×100(%)]; and

a conductive powder,

wherein the conductive powder is composed of carbon black and the conductive powder is about 5 vol % or more and about 25 vol % or less relative to the volume of the urethane resin, and

wherein the conductive powder has an average particle size of about 10 nm or more and about 30 nm or less.

2. The surface protective film according to claim 1 , wherein the content of the conductive powder is about 8 mass % or more and about 30 mass % or less relative to the mass of the urethane resin.

3. The surface protective film according to claim 1 , wherein the conductive powder has an average particle size of about 15 nm or more and about 25 nm or less.

4. The surface protective film according to claim 1 , wherein the urethane resin is formed by polymerization of a hydroxyl group-containing acrylic resin and an isocyanate.

5. The surface protective film according to claim 4 , wherein the hydroxyl group-containing acrylic resin has a hydroxyl value of about 50 mgKOH/g or more and about 400 mgKOH/g or less.

6. The surface protective film according to claim 4 , wherein the hydroxyl group-containing acrylic resin has a ratio [A]/([A]+[B]) of about 80% or more,

where [A] is a molar quantity of a side-chain hydroxyl group having less than 10 carbon atoms and [B] is a molar quantity of a side-chain hydroxyl group having 10 or more carbon atoms.

7. The surface protective film according to claim 6 , wherein the hydroxyl group-containing acrylic resin has a ratio [A]/([A]+[B]) of about 90% or more.

8. The surface protective film according to claim 1 , wherein the urethane resin includes at least one of a structural unit containing silicone and a structural unit containing a fluorine atom.

9. A transfer member comprising:

a base; and

the surface protective film according to claim 1 , the surface protective film being formed on the base.

10. An image forming apparatus comprising:

an electrostatic latent image carrier;

an electrostatic latent image forming device that forms an electrostatic latent image on a surface of the electrostatic latent image carrier;

a developing device that forms a toner image by developing, with toner, the electrostatic latent image formed on the surface of the electrostatic latent image carrier;

an intermediate transfer body including the transfer member according to claim 9 ;

a first transfer device that transfers the toner image formed on the electrostatic latent image carrier onto the intermediate transfer body; and

a second transfer device that transfers the toner image on the intermediate transfer body onto a recording medium.

11. A method for forming an image, comprising:

charging a surface of an electrostatic latent image carrier by a charging device;

forming an electrostatic latent image on the charged surface of the electrostatic latent image carrier by an electrostatic latent image forming device;

developing the electrostatic latent image with a developer to form a toner image;

transferring the toner image onto an intermediate transfer body including the transfer member according to claim 9 ;

transferring the toner image on the intermediate transfer body onto a recording medium; and

fixing the toner image on the recording medium.