Access Find the checkout record and add a return time

[Robert Novice]

I am setting up a database in Access 2007 to track equipment that is checked out and returned everyday several times a day. I have the checkout and return times working, but I need the Returns form which only has a text (to enter the equipment ID) to look up the last matching equipment ID record with no return time and insert the NOW() in that record.
The object here is to quickly allow a clerk to simply scan in and out equipment without any clicking.
It works presently with auto tab and input masks but there is a new record for every checkout and return. So I have to use a report to compile the associateID, checkout and return time instead of having a table that shows the User ID, Equipment ID, the checkout time, and return time in a single record.
The form is named Returns with the text box for the EquipmentID field and a hidden Return text box with a default value of NOW(). The table is called Events with an auto number as the primary key. The fields are:
ID(primary auto number), EquipmentID, AssociateID, Checkout, Return

Thanks

[Seth Schrock]

How do you differentiate between checking in vs. out? Do you have a item check out control and a item check in control? This would be the simplest design wise, but maybe not the simplest/fastest method for the users. If you have only one control for in or out and you want the database to figure out if you are checking it in or out based on the current status of the item, you will add much more complication to the design. However I do think that it is possible to do it. I just want to know how you are doing it so I don't have to figure out both methods and have only one used.

[Robert Novice]

One form Checkout puts NOW() in the checkout column of the Events table. For return time there is a separate form putting the NOW() in a column Return in the events table. Those separate forms are selected through a main menu.
So the short answer is that it is handled in separate columns by separate forms so I can compare the intervening time.

The input device the person checking in and out equipment will have is a hand held scanner to scan the barcodes on the equipment.

You can see that the tests I have run just give a separate entry for a check in and a check out. There are a couple of entries that have check out and return on the same line like I want but I typed those directly into the table to experiment with finding code that could differentiate between the two. (Which obviously did not work.) Instead of a single record where returns form finds the check out with the return column for that equipmentID is blank and puts the return time in that row.