Output probabilities for each class on tensorflow sigmoid function
You need to print output of sigmoid before tf.argmax is applied. It can be done with "tf.print", tf.print is a network node that does modify values. 

y_pred = tf.nn.sigmoid(layer_fc2)
y_pred = tf.print(y_pred ,[y_pred ])
self.y_pred_cls = tf.argmax(y_pred, dimension=1,name="predictions")


Docs : https://www.tensorflow.org/api_docs/python/tf/print