The Ramban (Miketz 42:8) asks why Joseph did not contact his mourning father for 22 years, being a mere 6 days distance from Egypt to Hebron. Some mefarshim find his explanation difficult. I thought of another explanation in the 1970's, based upon peshat (and supported by Midrashim) which basically proposes that Joseph thought his father was "in it" together with his brothers, and had no interest in knowing his situation. I carried this chiddush around with me for about 10 years, when I finally found someone who said it before: Looking through the front and back material of the Talmud Yerushalmi, I came across a work called "HaSh'mattas Mi-HaYerushalmi, by Shmuel Shraga Feigenson (where he quotes passages from sefarim that quote passages of the Yerushalmi that we don't have in our editions). At the end of this work, he is left with a half page of blank paper, and says that in order not to waste space, he will fill it with two of his chiddushim, one of which is the mehalach I have given for why Joseph did not inform his father he was alive. He closes by wondering why no of the "ba'aley ha-peshat" have suggested it!
In earlier Avodah posts, I have seen RYGB and others refer to R. Shmuel David Luzzatto's commentary which also gives this explanation. (I have yet to see it.) Shadal lived 1800-1865, and R. Shmuel Shraga Feivelson dated his work 1917.)
In VaYigash, Yehudah is petitioning Joseph (not knowing his identity). He quotes their father as saying, years after the sale of Joseph, "He has surely been torn [to pieces] and I have not seen him till now." One may wonder, if Yaakov thought Joseph had been torn to pieces, how could he have expected to see him? Apparently, the answer is he wasn't sure (as Rashi says, explaining why no one could comfort him as a mourner), and over the years, Yaakov reacted in perplexity to the evidence of the blood-soaked coat as follows: Joseph had either been killed, or he is alive. But if he is alive, "I haven't seen him till now" -- he should have been back by now; or at least he would let me know he is alive.
We can now see Yaakov's thought process, and why he thinks Joseph is dead, and entertains no thoughts of retrieving him.
On the other hand, what was Joseph thinking? Yehudah's account revealed to Joseph for the first time his father's thoughts. And at this pont, being told of his father's boundless and continuous love for him, Joseph finds himself unable to contain himself and reveals his identity. What, then, until now, did Joseph think his father's thoughts were? This, I suggest, will explain why Joseph refrained from contacting his father until Yehudah's revelation -- including the years that Joseph was Potifar's servant, while he was in the dungeon, and while he was viceroy.
Joseph did not know that his father thought he was dead! At first he was only told by his brothers, "V'ha-yelled aynennu," -- "the boy is not [with us]." He knew nothing of the coat being dipped in blood, nor of his father's reaction to whatever happened.
What he saw was that his father did not seem to be interested in retrieving him.
And the last thing his father did was sending him out to his brothers, knowing full well of their antagonism toward him, "to see their welfare." Now, if there were grounds to think they were in an unsafe situation, how would sending the young Joseph help? Joseph obeyed his father despite the irrationality, but why did Yaakov send Joseph out to a makom sakana, a dangerous place? Unless...
Rashi cites the Zohar, which says that Yaakov's sending Joseph was Hashem's interfering with his normal thought-process. "He sent him out from Aimek Hebron, the deep place of Hebron. -- But Hebron is highland, not deep! It means that Yaakov's sending Joseph to his brothers was part of "oso eitza amuka," that deep, divine, master plan, to eventually put Yaakov in a situation forcing him against his will to leave Canaan and relocate in Egypt. Indeed, Malbim further cites the Zohar which says that after Joseph's disappearance, every time Yaakov thought back to his sending Joseph away, he felt as if spears were penetrating his body. "Why did I do such an irrational thing as sending my beloved Joseph out to a dangerous place?!" The answer is that it was only because of Hashem's intervention with his free will that he did so.
But Joseph could not know this.
All Joseph knew is that his father sent him to his brothers, who put him in a pit and sold him to Egypt, because they considered him a moreid b'malchus or a navi shekker.
And all Joseph knew is that when he told his dreams to Yaakov, Yaakov responded by berating him, "Do you think I and your mother will prostrate ourselves before you?" "Va-yig'ar bo aviv," his father expressed anger at him." Now of course, the posuk goes on to say "V'aviv shomer ess ha-davar," his father kept an eye on the matter, meaning as Rashi says, he thought -- or perhaps hoped -- that this would really happen.
But again, Joseph was not a mind reader. All he knew was that his father, like his brothers, was angry at him for his dreams, and that his father, apparently unconcerned about his welfare, sent him out to his brothers who considered him worthy of execution and who sold him to Egypt.
Strong reasons to think that his father felt the same way about him as did his brothers.
And if his father did not feel this way, and was not part of the scheme to eliminate him, why, once the brothers came back, didn't Yaakov order them to get down to Egypt and rescue him? (Again, Joseph had no idea about the dipped-in-blood ruse, nor that his brothers would lie to Yaakov.) And what about Reuvain, or Shimon? Why weren't they rescuing him? (The Midrash assumes that Binyamin knew Joseph's situation, and named his sons accordingly.) Was Binyamin dead? Was his father?
So now, while working in Potifar's house, and when sitting in prison, as long as he did not hear from his father or brothers, he hoped for the day that his father, knowing full-well, in Joseph's mind, that he was there, would have pity on him and send word that he was forgiven. And when he became viceroy, and his dreams were beginning to come true, he would not send that news to his father, out of respect. He would not say, in effect, "See, you thought my dreams were dreams if grandeur, that I was a navi shekker or moreid b'malchus; but look! I am now the second to the king of Egypt!" He would not gloat.
This is why he did not send word to his father that he was alive. He thought his father was well aware that he was in slavery in Egypt, and that that is where he wanted him to be. Otherwise, he would have come to get him. Unless his father and Binyamin were no longer alive. He connived a way (without revealing himself, out of fear of what his brothers would do to him) to see that Binyamin was still alive, but what about his father?
And so, once Yehudah revealed to Joseph that his father thought he was dead, Joseph put the pieces together, and cried, "I am Joseph! Is Tatty really still alive?!" And he realized that all that happened had to be something arranged by Hashem, to maintain the family and purify and build the Jewish Nation.
I would also add that the episode can be symbolized by a theme in the pesukim: If one were to produce a play about the account of Joseph and his brothers, the costume director would be very busy. Each scene of Joseph's life is depicted in the pesukim with a change of clothing: The special garment Yaakov makes for him; the brothers strip him of his garment; Potifar's wife strips him of his clothing; when he's taken from prison he is given a change of clothing; Pharaoh places upon him royal wear (and Joseph gives to Binyamin five times as many garments as he gives his other brothers). The pesukim did not need to tell us these details to get the story across. Perhaps it symbolizes the theme that everyone saw Joseph HaTzadik only externally, his father as a leader, the brothers as a criminal, Potifar's wife as a potential adulterer, Pharaoh as a strategist. But inside, Joseph HaTzadik was the same tzadik throughout his life and its vicissitudes.