Chinese food is very popular in Japan and it is not considered as cheap dining at all. Then, many Chinese restaurants are run by native Japanese or Chinese origin Japanese.
The food are adapted to Japanese way and it is different than the dishes in European Chinese restaurants. Then, take away is not so common behavior. Therefore there is almost no Chinese food stand specialized in take away.
There are two types of Japanese Chinese restaurants. The first one is mostly offer ramen noodles and other several dishes which are not to be considered to share by a group. The second one is a restaurant which considered to be shared by a group.
Therefore if you are traveling alone and want to try the Chinese food in Japan, better to go to restaurant chains as like Gyoza no Ohsho or Hidaka-ya. They offer several meals with rice and soup.