T6045 TN002 Rev New

Line Printers Give Paper Jams And Cause Bad Paper Stacking!

My line printer consistently fails with paper jams and will not stack the paper. I end up with paper spread out all over the floor or in a heap on the paper tray and paper "scrunched up" inside the lid. Your printer is useless!!!!!!!!!

Now just hold on a minute. The Tally line printer is a first class printer and when treated with respect, it will give years of service. Ok, so it will suffer from paper jams just like any printer will from time to time, but let's ask the question Why?

To answer this question, we need to know a few things about our Tally line printer!

Firstly, let's have a look at the printer's paper path and the stacking tray at the back.

Please note that if you have a desktop printer then much of this application note will not apply to you. This note is specifically for users of the stand alone printers on a pedestal. These printers include the MT645, MT661, MT691, T6045, T6050, T6090, T6100, T6140 printers.

The paper is loaded from below the print mechanism and is fed up through the mechanism and then out of the back of the printer at the top and allowed to drop onto a catchment tray attached at the bottom of the printer at the back. The paper passes through tractors below the print mechanism (except for the T6045 & T6050), through tractors above the print mechanism, out of the printer through a metal chute, down through a metal guide and then drops freely between metal chains on to the catchment tray. On those printers that have an open pedestal, they may not have the metal guide and chains at the back of the printer. The metal guide is hung on the back of the printer and a plastic hood normally sits over the top of the metal guide to reduce noise from the printer. On some printers, the metal guide is pre-assembled inside the plastic hood.

At first, you may think that there are a lot of parts and places in the paper path where the paper can catch and cause a jam. Experience has shown that when talking with users that experience paper jams in their printers, invariably they report that the jam always occurs in the metal chute at the top of the printer. Of those printers that have been looked at by Tally Technical Support, the user is correct in what he sees, but the root cause of the problem is bad installation of the printer and/or "bad" paper. When this has been pointed out, the user usually finds it difficult to believe, but in time he has to admit that it is true!

So, how do we install the printer correctly. Firstly, we read the operators manual. This tells us how to install the metal paper guide on the back of the printer. On the MT645/661/691 and 6140 printers, this involves hanging the metal guide on the back of the printer in the metal bracket provided. The hood then locates in the same metal bracket. When installing the metal guide on these printers, ensure that the guide is fully down inside the bracket. On the T6045, T6050, T6090 and T6100 printers we need to hang the hood over two small metal brackets at the back of the printer and we must ensure that the two screws that sit proud at the back of the printer locate in the appropriate cut outs in the hood. When you are installing the hood for the first time, it is difficult to push the hood right down into the brackets. A reasonable amount of force will be needed to ensure correct location. On the T6045, T6050, T6090 and T6100 printers you will find a small green and yellow wire attached on one side. This wire has a small receptacle on the end which will mate with a small tab on the printer body nearby. Connect the wire to the tab by pushing the receptacle onto the tab.

Ok. So now we have our metal guide and hood installed. Now we must release the metal chains. When we have released them, we must ensure that they hang freely and are not tangled up. You will note that some chains are longer than others. This is deliberate and you will probably notice why this is deliberate when the paper starts to stack. Before we finish with the chains, look closely at the rings that are attached to the metal guide and have the chains hanging from them. Are they assembled correctly? If they are positioned so that the paper can catch a sharp edge, then move the rings and change their position as necessary.

So now install the catchment tray. This one you cannot get wrong as there are only two holes for the tray. However, it is worth looking at the holes before you install the tray. Are the insides of the holes bare or covered in paint? If they are not bare, then please scratch the paint off the inside of each hole. The reason for doing this is to make sure that there is a good metal to metal connection between the tray and the pedestal. If there is not a good metal to metal connection, then static charges will build up on the tray and this can cause problems with stacking paper.

Ok so now we have installed the printer and the paper guides etc. Before we load paper into the printer, lets just look at where we have sited the printer. Can you feel a breeze. If you can, then perhaps the air-conditioning is blowing air round the printer. If this is so, then move the printer or at least prevent the moving air from getting to the back of the printer. If this breeze is allowed to persist, then you may well find that paper does not stack properly!

Now lets load paper into the printer. There is a correct way to load paper and to find out what this is, let's look in the manual. Yes, there are the details. Note very carefully that it states that you should manually feed the paper up and through the print mechanism, past the top tractors and through the upper paper guide (or chute) and out of the rear paper slot. If the hood is installed, then push the paper through until you can see it coming down between the chains. Only now should you place the paper in the top tractors and close the tractor covers. You may think that this will waste a few sheets of paper, and you are correct. However, the price of those few sheets of blank paper is negligible compared with the frustration and cost of having paper jams and losing a complete print run that you will have to reprint!! Now locate the paper in the lower tractors (except T6045 & T6050) and close the lower tractor covers. Complete the loading of paper by closing the Form Thickness Lever. See the manual for full details and diagrams.

Just one more task to do which is to set the Top Of Form. Follow the instructions in the manual to do this.

Now we are ready to print, but beware, you may still get paper jams. We have to watch the paper stacking the first few sheets to ensure that the paper folds the correct way into the tray. Assist the paper to fold the first couple of sheets just to make sure all is well.

The printer should now stack the paper correctly but there are some conditions which will prevent this from happening. One condition is air movement. Watch the paper as it stacks. Is the paper "swaying in the wind". Stop that air movement or you may get problems!

Is the paper too lightweight? The Tally printer specifications state that the paper should be a minimum of 55 gsm (grams per square metre). Undoubtedly, the printer will print on 55 gsm paper and feed it out of the printer, but if you have used this lightweight paper you may well have seen a "rolling " of the paper during stacking. The folds may stack higher than the centre of each sheet. This is caused by air being trapped between the sheets at the folds.

This is not a fault of the printer.

The paper is not heavy enough to press the air out from between the sheets at the folds. Please use heavier paper to prevent problems!

Are the folds of the paper sharp? If they are, the folds could catch on the chains and cause stacking problems. Use paper with less sharp folds.

Are the folds distinct or does the paper look like it has come off of a roll? If this is the case, then the sheets may not fold and stack correctly in the tray.

But what has all this got to do with the paper jams above the tractors inside the printer you ask?! Well here lies the reason. If the paper does not stack flat for any of the scenarios given above, then, the top of the stack gets nearer to the bottom of the hood quicker than it should. When this happens, the paper finds that it has nowhere to go and inevitably it resists and stops. But the printer tractors are still trying to feed paper out. I think you can guess the rest! The paper cannot get through the chute so it folds back into the printer and eventually comes out of the tractors. The printer then stops with a Paper Motion Error and now it's up to you to sort out the mess!

There is one other reason for poor stacking. This may be due to the paper being fed through the printer too fast during non printing areas. With the printer not printing, press the Form Feed key on the printer control panel and watch how fast it feeds the paper. Sometimes this can be too fast and the solution is to slow down the paper slew rate. The easiest way to do this is to enable the Heavy parameter in the printer menu (see printer manual for setting this parameter). Enabling Heavy does just one thing. It slows down the slew rate of the paper. There have been many examples of this parameter resolving the paper stacking problems and preventing paper jams. It does not slow down the print speed of the printer, it merely reduces the slew rate of the paper.

So next time you see paper jams in the line printer, take a look at the back of the printer. See how the paper has been stacking. If the paper is stacking badly, you cannot expect the printer to know this. However, you will most likely see the reason for the paper jam.

Speaking from more than twelve years of experience working with line printers, I can categorically say that all paper jams that I have seen in line printers have not been the fault of the printer, but have been due to the type of paper being used, the weight of paper being used, or to the environmental conditions around the printer. The minimum recommended paper weight for single part paper is 70 gsm with a preferred minimum of 75 gsm.

Let's face facts, you have probably spent thousands of pounds, dollars or whatever currency you have to purchase your first class printer. Let's not expect it to print on and feed substandard paper. Let's treat it with respect and get years of trouble free printing from it.