On Douban, there is generally no function of downloading comics directly. Douban is a social networking site where users can evaluate, collect and share cartoons. If you want to download comics, you can try the following methods:

1. Find a comic resource website: Search for a website dedicated to downloading comics through a search engine. These websites usually provide free or paid comic resources, where you can search for the comics you want to download and download them.

2. Use third-party applications or software: There are some third-party applications or software that can help you download comics from Douban. You can search the relevant download tools through the app store and then follow the instructions of the software.

It should be noted that downloading comics from unofficial channels may have copyright problems. Please ensure that your actions comply with relevant laws and regulations. At the same time, it is a better choice to respect the work of comic authors and support genuine comics if possible.