Both were on target against Crewe last Saturday, Roberts scoring twice and Ellington finding the net with a penalty for his first goal in more than a month.
Jewell said: "I was really pleased because I like my strikers to be scoring goals, and their return this season is good.
"If they can get 50 between them by the end of the season I would be happy.
"Jason's contribution in the Crewe game was excellent, not just the two goals, but his all-round play and ability.
"He's been unfortunate in the last couple of weeks not to have got more goals, so it was great to see him off the mark so quickly on Saturday.
"We've asked Jason to be more of a leader rather than just being part of the background.
"He is one of the players here who has played in the Premier League and knows what it takes to get out of this league.
"We need leaders out on the pitch and the more we have, the better the team will be.
"Jason is a handful for defenders with his unbelievable pace, and his goals record since he has been here is very good.
"As for the Duke, he hasn't been at his best in recent weeks and I didn't think he was at his best on Saturday until he scored.
"But suddenly he looked a different player and strikers tend to be like that.
"It was a pressure goal he scored from the spot and it looked like a big weight had been lifted off his shoulders.
"I'd told him before the game he would score, because he's got a good record against Crewe, and hopefully he can go on a roll now."
Jewell still intends to bring in another striker to keep Ellington and Roberts on their toes, his chase of Stoke's Ade Akinbiyi now a month old.
He's weighing up a second bid for the 30-year-old powerhouse and earlier in the week was still waiting to hear the Potters' asking price.
Latics are one of four clubs tracking Akinbiyi, Sheffield United, Nottingham Forest and Burnley the others.
The player himself doesn't seem in a rush to leave the Britannia Stadium, his recent dispute with the club concerning their unwillingness to hold talks over an extended contract.
His agent Gary Mellor said: "We have heard about all the interest in Ade from Championship clubs, but the call we would most like to hear is from the chairman of Stoke.
"Ade has always maintained that he has been happy at Stoke."
* Latics reserves were in action this afternoon against Walsall at the Robin Park Arena.