Image forming apparatus and image forming method

1. An image forming apparatus comprising:

a first toner image forming unit that forms a first toner image with use of a first toner, the first toner including a binder resin, the binder resin having a weight-average molecular weight that falls within a range of from 12297 to 14019, both inclusive;

a second toner image forming unit that forms a second toner image with use of a second toner; and

a transfer section that transfers the first toner image onto a print medium, and transfers the second toner image onto the print medium in a region that overlaps a portion or all of a region where the first toner image has been transferred, the print medium including a polymer compound.

2. The image forming apparatus according to claim 1 , wherein the transfer section transfers the second toner image onto the print medium within the region where the first toner image has been transferred.

3. The image forming apparatus according to claim 1 , wherein

a first weight, per unit area, of the first toner image transferred onto the print medium falls within a range of from 0.20 milligrams per square centimeter to 0.40 milligrams per square centimeter, both inclusive, and

a sum of the first weight and a second weight, per unit area, of the second toner image transferred onto the print medium falls within a range of from (X+0.30) milligrams per square centimeter to (X+0.45) milligrams per square centimeter, both inclusive, where X is the first weight.

4. The image forming apparatus according to claim 3 , wherein

the first weight comprises a weight of the first toner image per unit area in an overlapped region in which the region where the first toner image has been transferred and a region where the second toner image has been transferred overlap each other, and

the sum comprises a sum of the first weight of the first toner image per unit area in the overlapped region and a weight of the second toner image per unit area in the overlapped region.

5. The image forming apparatus according to claim 1 , wherein a surface, of the print medium, onto which each of the first toner image and the second toner image is to be transferred has a Bekk smoothness of no lower than 100000 seconds.

6. The image forming apparatus according to claim 1 , further comprising a fixing section that fixes, to the print medium, the first toner image transferred onto the print medium, and after fixing the first toner image to the print medium, fixes, to the print medium, the second toner image transferred onto the print medium.

7. The image forming apparatus according to claim 1 , wherein the first toner comprises a clear toner.

8. The image forming apparatus according to claim 1 , wherein the polymer compound includes polyethylene terephthalate, polyvinyl chloride, or both.

9. An image forming method comprising:

forming a first toner image with use of a first toner, the first toner including a binder resin, the binder resin having a weight-average molecular weight that falls within a range of from 12297 to 14019, both inclusive;

forming a second toner image with use of a second toner;

transferring the first toner image onto a print medium, the print medium including a polymer compound; and

transferring, after the transferring of the first toner image onto the print medium, the second toner image onto the print medium in a region that overlaps a portion or all of a region where the first toner image has been transferred.

10. The image forming method according to claim 9 , wherein the second toner image is transferred onto the print medium within a region where the first toner image has been transferred.

11. The image forming method according to claim 9 , wherein

a first weight, per unit area, of the first toner image transferred onto the print medium falls within a range of from 0.20 milligrams per square centimeter to 0.40 milligrams per square centimeter, both inclusive, and

a sum of the first weight and a second weight, per unit area, of the second toner image transferred onto the print medium falls within a range of from (X+0.30) milligrams per square centimeter to (X+0.45) milligrams per square centimeter, both inclusive, where X is the first weight.

12. The image forming method according to claim 11 , wherein

the first weight comprises a weight of the first toner image per unit area in an overlapped region in which the region where the first toner image has been transferred and a region where the second toner image has been transferred overlap each other, and

the sum comprises a sum of the first weight of the first toner image per unit area in the overlapped region and a weight of the second toner image per unit area in the overlapped region.

13. The image forming method according to claim 9 , wherein a surface, of the print medium, onto which each of the first toner image and the second toner image is to be transferred has a Bekk smoothness of no lower than 100000 seconds.

14. The image forming method according to claim 9 , further comprising:

fixing, to the print medium, the first toner image transferred onto the print medium; and

fixing, to the print medium, after the fixing of the first toner image to the print medium, the second toner image transferred onto the print medium.

15. The image forming method according to claim 9 , wherein the polymer compound includes polyethylene terephthalate, polyvinyl chloride, or both.