All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
An employee in a government is included in what is called in Islamic jurisprudence as "Specific hiring" (in which a person is paid for being on duty for a certain period whether or not the employer assigned a task for him), and he is entrusted on whatever work he is given, and over the equipments that are used for the purpose of work. So, it is not permissible for an employee to use work equipments for his personal benefit, as this contravenes the terms of the work contract, and it is neglecting the trust one is entrusted with. Included in the definition of the trust is any right that other people have on you, and the right of these equipments is that they should only be used for work purposes only. Allaah Says (what means): {Verily! Allaah commands that you should render back the trusts to those, to whom they are due.}[Quran 4:58]. This is with the exception when the used equipment or device does not change and is not affected by personal use, like the ruler for instance. There is no harm for an employee to use this device once or twice or more, as it is not affected with personal use. As regards a photocopier, there is no doubt that it is affected by personal use, as it consumes ink and paper. However, if the employer or the department for which you work gives you permission directly or indirectly to use this device, then there is no harm.
It should be noted that the permission is obtained if it is known in people's custom that it is granted just as it is obtained by a clear notice. A person who has no right to give permission, his permission is not considered, even if he is a director or a chairperson. If a person, who has no right to give you permission, gives you permission, then he is sinful exactly like the person who is given permission.
Finally, whoever has done this should repent to Allaah, regret what happened, be determined not to return to this sin again in the future, and give back what he has taken from work, if it still functions, but if it is late or that it is impossible to give it back, then one should return its value.
In the case mentioned in the question, it is not possible to return the papers after using them as they can only be used once, and it is not permissible to discard them when it is still possible to benefit from them. So, the only alternative that remains is to return its value as previously discussed.
Allaah Knows best.