OKI c931 Printer Curling Issues

Hi all!

I run a small stationery business from my home. I exclusively use 120 lb. Smooth Digital i-Tone cardstock from Mohawk. Somehow I managed for 3+ years to operate at a substantial volume (~4,000 prints per month) using an HP m553n (Don't laugh! I went through two of these and a number of refills of toner). Customers and clients have always been extremely happy with the print quality and end product, but as you can imagine there have always been kinks to work out in the day to day.

After years and years of discussion and debate, I finally decided to move forward with purchasing the OKI c931, which even though the business is doing well, is a substantial investment for this little operation of mine. I was really hopeful this would be a huge upgrade from my little HP m553n and improve quality and process even further but ... yikes.

The c931 is meant to be able to handle up to 360 gsm from the MP Tray. The paper I use is ~325 gsm, cut down to 4.25"x5.5". It's a relatively straightforward pathway from what the tech who installed it is telling me, but it's curling the edges of the paper regardless of the setting I try. I've tried all Media weights, turning High Humid Modes on, Moisture control, adjusting the printer speeds. Nothing fixes it. It's especially apparent when running your fingers over the paper that a ridge is being created by an internal wheel. This never ever happened using the HP m553n. See attached.

Also worth nothing that the paper is coming from shrink wrapped packages that are not opened until ready to print, so I really don't think it's a humidity issue.

Does anyone have similar experience with this machine or is anyone able to share insight? The reseller I purchased from has so far been largely unhelpful and pretty unresponsive.

Thanks in advance!

 

We have the C942 which I believe is the same machine, only with a 5th station for the white toner. We bought it primarily to run envelopes, but we occasionally run flat sheets, usually 80# or 100# cover. I haven't noticed the curl being an issue. A few thoughts:

1. The HP you used to have was a letter size printer, while the OKI is capable of printing up to 13x19 sheets. Have you changed to a larger sheet size? If so, the grain direction is often different and can affect curl. The paper size on the package will either list the grain direction as the first dimension, or it will underline it. You can order most papers in both grain directions.
2. The OKI offers a face down or face up output mode. Whichever mode you're using, try the other. We always use face up because it's the straightest path. Face down curls the paper tightly to come out the top.
3. Are your customers rejecting the jobs since they are curled? I know it's not desirable and a bit annoying even, but when the pieces are handed out one at a time, the average person doesn't pay attention to that detail, and it will probably be fine. We graphics people pay more attention to this stuff and think our customers will hate it, but that's often not the case. If it's really bothering you, and the above options don't work, you can always manually de-curl the paper yourself by just bending a stack the opposite direction a bit.

 

Thank you so much for your thoughtful reply!

Interestingly enough, it does not affect envelopes from the MP Tray. I am not sure why. It does, however, jam them quite a bit. It happened a few times even during install which stumped the tech installing it. We replaced the wheel with an envelope feeder and it seems to have fixed that issue for now (fingers crossed).

1. The HP you used to have was a letter size printer, while the OKI is capable of printing up to 13x19 sheets. Have you changed to a larger sheet size? If so, the grain direction is often different and can affect curl. The paper size on the package will either list the grain direction as the first dimension, or it will underline it. You can order most papers in both grain directions.
   
   Originally I would've loved to use a larger sheet size but I sell personal stationery cards and it's important for the end product that they are all cut perfectly to the same size otherwise a stack of them can end up looking messy. It's also extremely time consuming to cut down individual cards for each order (I sometimes have orders upwards of 200 cards/set). So unfortunately, a larger sheet isn't an option.
   
   
2. The OKI offers a face down or face up output mode. Whichever mode you're using, try the other. We always use face up because it's the straightest path. Face down curls the paper tightly to come out the top.
   
   Currently it's happening on face up, but I am going to try face down next! Thank you for this recommendation!
   
   
3. Are your customers rejecting the jobs since they are curled? I know it's not desirable and a bit annoying even, but when the pieces are handed out one at a time, the average person doesn't pay attention to that detail, and it will probably be fine. We graphics people pay more attention to this stuff and think our customers will hate it, but that's often not the case. If it's really bothering you, and the above options don't work, you can always manually de-curl the paper yourself by just bending a stack the opposite direction a bit.
   
   My customers are super tuned into the details on the end product. These are often used as wedding thank you notes, baby shower thank you notes, and personal stationery. I once had a client reach out because a period for the middle initial of a name was off by 1/16". As a stack, the curl is so much more apparent. These are packaged in clear boxes with envelopes behind them so any bend in the paper is immediately visible.

Really appreciate you taking the time to offer up help and suggestions!

 

I think you misunderstood my first point. I wasn’t suggesting that you should use larger sheets, I was asking if you switched to larger sheets, which could be different grain directions. If you’re using precut sheets, then the grain direction of those can vary from package to package since they are cut out of larger parent sheets. I’d suggest rotating your sheets 90 degrees to feed from the long edge if you’re feeding from the short edge, and vice versa.