Codeigniter caching the Captcha

Hi all,

I am creating a single page website which has a form in it (with captcha). I implemented codeigniter cache by putting in the following line at the start of index function as i just have two function viz. index which loads website and other to validate the form and submit in DB

$this->output->cache(10080);

The problem is this statement is causing the captcha name to be cached as well. first time the site opens fine but then when it is opened for the second time, the captcha image does not load. The console log shows the image name to be the same as first time no matter how many time i refresh

Is there anyway i can define captcha as an exception for caching.

Thanks a lot in advance

No, but a I have a better question - why would you want to cache a single page website?