you will have to define the range of records that you want the report to print. The computer has no way of knowing that you want the most recently entered records printed out in the report. It's up to you to define the criteria for the report.
There are several ways of tackling this issue, the first way would be to include a flag in your record, a boolean field, once the report has been printed, set this field to true, then set up your report to it only show un-printed records.
you could provide a date range, only printing out records saved today for example.
Instead of a boolean field you could use a number field linked to another table that would identify today's batch of records, that way you would be able to print the same group of records off again.