Depending on the types of printers you have...

Most manufacturers have a discovery tool.

Lexmark has a pretty good one that will scan the network for Lexmarks.
HP aslo has one that will identify each jetdirect card.

They should have been included with the package when you bought the printers.

OR

You can get them at no charge form the manufacturer's site.

Very easy to use and give you the mac and ip address along with share name and other info.

A lot of the newer printers can be configured using a web browser....

http://ipaddressofprinter

Hopefully he didn't password protect them....

Here is a link to HP printer discovery docs and how they work.
Here is a link to the MarkVision utility which scans the network for lexmark network printers.

I don't know why someone would use DHCP for printers though... I have a block of IPs for printers and they are assigned by static addresses. It is much easier to diagnose problems from your desk using the web interface than running all over the building(s) to find out that someone is out of toner or has a paper jam.

EDIT one last time:
THIS is what you are looking for.

http://www.hp.com/go/webjetadmin

Remote installation, configuration, and management of HP Jetdirect-connected print servers, non-HP printers that support the Standard Printer MIB, and printers with embedded Web servers Alerts and consumables management. Remote firmware upgrades for HP Jetdirect print servers Asset tracking and utilization analysis.