Most Canon printer users will be familiar with the Ink Status monitor that can be accessed in the maintenance tab of the printer driver and also pops up while printing.  However, there is another ink status monitor available to those who have installed their printer as a network printer and is available via the Remote User Interface (RUI).

I have done a comparison between the 2 ink monitors, for my Pro100S, at low ink levels.  While I believe they both rely on the same data, the Remote UI (ie RUI) monitor, in my opinion, is better.  The first file attached shows both monitors taken from screenshots of the exact same ink levels and combined into the one file for easy comparison.  From a screen size point of view the RUI is significantly better.

Now have a look at the Magenta, as an example.  Would you say they are presenting the same information in the two graphs?  If not, which one is more correct/accurate?  I will discuss this further down in this post.

To open the RUI on a Windows PC, I use this method:  Open a File Explorer window and navigate down to and select “Network” on the left panel.  On the right panel you should see your printer under the “Printers” group, if it has been installed.  Double click on this icon and you will get a request for a User Name and a Password.  Use “ADMIN” as the User Name and “canon” as the Password.

I only got asked to login the first time, using this method, so not sure if that is because I have not turned my PC off since the first time I opened the RUI.  I did add the RUI as a bookmark on the “bookmarks bar” (I use Chrome) and again was only asked the first time to login.  The Ink Level display shows 4 ink horizontal colour bars on the left and 4 on the right if you have a wide screen, whereas for a narrow screen it shows all 8 horizontal colour bars in one single column.  The bars show slight “feathering” on the right of the bar graph to represent that it is not an exact presentation of the ink levels.  ie.  It is an estimate and the graphs do not move gradually, they jump suddenly.  In fact they always show more ink available than there is and will only drop to the next level when ink is estimated to be at the top of that next level.

To show the improved graphics at low ink levels, I temporarily replaced 2 full carts with one empty (Yellow) and one low (Black).  The attached file is from a screenshot that I scaled/cropped and added a percentage scale.  So it is quite clear that the Yellow shows 5%, Black 10%, Magenta 20% and PC 30%.  I have cropped out the other 4 tanks as they did not really add much information.

I decided to peek at the scripts to see if they revealed any detail not being displayed.
Each cart has 3 numeric parameters that were retrieved.  The first parameter is the colour, the second parameter is the ink level, ranging from 0 = full to 11 = Empty.  However, the value 10 is the one that coincides with the Empty warning and the graph actually shows 5% remaining.  The 3rd parameter has 4 values as follows:  0 = “Normal”, 1 = “Low Warning”, 2 = “Empty and 3 = “Ink Monitor Disabled”.   I am making an assumption re value = 3, as I did some simulation by substituting different values in the script and the value “3” gave a blue “?” inside a white circle to the left of the bar graph.  Another assumption is that the ink level parameter would be set at ‘11’ coincidentally with the 3rd parameter being set to ‘3’ (ie. “Ink Monitor Disabled”).

See the small cropped screenshot of the parameter values returned for my actual ink levels which correspond to the bar graph posted:

For the 4 carts shown in the attached RUI screenshot, the parameter for the ink levels were:
Yellow (10) Empty, Black (9) Low, Magenta (8] and PC (7).  Parameters 0 to 9 can be multiplied by 10 to give percentage ink used.   eg. Magenta is 80% used or 20% remaining. The display for carts with low ink warning is now much better than the standard ink monitor, showing 90% used or 10% remaining, which is the same value I get by measuring the weight of ink in carts that have reached this level.

I have attached a zoomed cropped screenshot of the normal Ink Status monitor, with a grid overlaid and percentage line added on the left.  The screenshot was from when the I was initially warned that the GY cart was Empty.  I have also superimposed the Ink Level parameter value that would have applied for each cart  directly under each cart.  So as in the case of the RUI monitor we have representations of 7, 8, 9 and 10 to compare the 2 graphs.  They just happen to be of different colours.
 
I will let you do your own comparisons, but in my opinion the normal ink status monitor is showing higher than the RUI monitor in all cases.   In addition the weight of the Magenta cart, in the RUI case, indicates it had 18.98% of ink remaining (or 81.02% empty) and was based on a parameter value of 7, which changed to 8 first use after taking the screenshot.  So that suggests the RUI graph is quite accurate as well as being easier to evaluate because of its size.

A few points to close on; the case where the Ink Level parameter is “9” should be very accurate, because that is determined by an optical sensor.  The case where the Ink Level parameter is “10” is very brief, because you have to make a choice at that point to either replace the cart or override the monitor, resulting in either “1” or “11” respectively.   Between “9” and “10” the display shows 90% empty and suddenly changes to empty.  If you were using the normal Ink Status monitor it looks like less than 90% has been used in this period, so can be a surprise the first time it suddenly changes to empty.

I have also found the parameter value definitions for the above 3 parameter in the scripts.  There are 18 colours defined.  ie.  The application is generic to several Canon printers.
Sorry but I had to squash all the files down to fit them inside the 256K allowance.  Hence the quality is not the best.

I thought it worth posting this screenshot, because it is the first one I have of high ink levels, other than full and I think it best shows the benefit of the RUI monitor over the normal Ink Status Monitor.

There are now 3 carts where 10% of ink has been used. ie.  Y, PM and GY.  However, on the old Ink Status Monitor it is almost impossible to see it is not full, particularly on the Yellow.

A few other points worth noting:
- My PC rebooted a few days ago, after a Windows update and when I went to open the RUI, I was asked to log back in.  Not surprising, but it failed the first time and worked the second time.
- Looking at the 3 carts that are being reported as 10% empty, you would be excused for thinking they were full carts, as just a tiny bubble or 2 has appeared at top of the ink reservoir.