Table 1.
Summary of the sample designation, device, and toner type information for the known origin samples analyzed.
| Sample Number | Brand and Model | Toner Type |
|---|---|---|
| 1 | Canon iR 2230 | Canon Toner C - EXV 11 |
| 56 | Canon iR 3300 | Canon Toner C - EXV 3 |
| 66 | Canon iR 2200 | Canon Toner C - EXV 3 |
| 144 | Canon iR 3025N | Canon Toner C - EXV 11 |
| 161 | Canon iR 3035N | Canon Toner C - EXV 12 |
Figure 1.
Standard text on which magnetic flux was measured for all phase 1 samples. 8 pt, 10 pt, and 12 pt font respectively.
Figure 2.
Plots of magnetic flux a function of toner area for all phase 2 samples with linear trend lines showcasing the range in R2 coefficients. Although the linear model was found to effectively model the relationship between toner area and magnetic flux, there were some limitations to the linear model which could contribute to the observed variation in R2 coefficients.
Figure 3.
Box plot of all phase 2 data. Note the visual differences between groups. ANOVA was used to check for significant variance within groups as well as between the groups that appear to overlap (samples 1 and 161).
Table 2.
Summary of results of within-group ANOVA testing of phase 2 data (a=0.05, pcrit=0.05)
| ANOVA Within Groups | F-stat | p-value |
|---|---|---|
| Sample 1 - 8 pt, 10 pt, and 12 pt | 1.43 | .271 |
| Sample 56 - 8 pt, 10 pt, and 12 pt | 134 | <.001 |
| Sample 66 - 8 pt, 10 pt, and 12 pt | .220 | .653 |
| Sample 144 - 8 pt, 10 pt, and 12 pt | 11.4 | .012 |
| Sample 161 - 8 pt, 10 pt, and 12 pt | 3.20 | .117 |
Table 3.
Results of within-group Welch 2-sample t-tests (α=0.05, pcrit=0.05).
| Welch 2 Sample t-test Within Groups | p-value |
| Sample 1 font 8 and Sample 1 font 10 | .010 |
| Sample 1 font 8 and Sample 1 font 12 | .507 |
| Sample 1 font 10 and Sample 1 font 12 | .317 |
| Sample 56 font 8 and Sample 56 font 10 | .168 |
| Sample 56 font 8 and Sample 56 font 12 | .112 |
| Sample 56 font 10 and Sample 56 font 12 | .897 |
| Sample 66 font 8 and Sample 66 font 10 | .007 |
| Sample 66 font 8 and Sample 66 font 12 | .033 |
| Sample 66 font 10 and Sample 66 font 12 | .055 |
| Sample 144 font 8 and Sample 144 font 10 | .005 |
| Sample 144 font 8 and Sample 144 font 12 | .009 |
| Sample 144 font 10 and Sample 144 font 12 | .656 |
| Sample 161 font 8 and Sample 161 font 10 | .207 |
| Sample 161 font 8 and Sample 161 font 12 | .014 |
| Sample 161 font 10 and Sample 161 font 12 | .391 |
Table 4.
Results of between group 2 sample Welch t-tests (a=0.05, pcrit=0.05).
| Welch 2 Sample t-test Between Groups | p-value |
| Sample 1 font 8 and Sample 161 font 8 | .002 |
| Sample 1 font 10 and Sample 161 font 10 | .025 |
| Sample 1 font 12 and Sample 161 font 12 | .006 |
| Sample 1 font 8 and Sample 161 font 10 | <.001 |
| Sample 1 font 8 and Sample 161 font 12 | <.001 |
| Sample 1 font 10 and Sample 161 font 8 | .188 |
| Sample 1 font 10 and Sample 161 font 12 | <.001 |
| Sample 1 font 12 and Sample 161 font 8 | .111 |
| Sample 1 font 12 and Sample 161 font 10 | .026 |
Figure 4.
Strip charts of the population data from phase 3. The strip charts highlight the repeatability of the method based on three replicate measurements. Most of the values are close or overlapped within a sample, with very few samples exhibiting large dispersions. Zero values were also recorded for some samples.
Figure 5.
Histogram of the population distribution with a kernel density estimation added to estimate the probability density function of the collected magnetic flux measurements. This aids in the assessment of the rarity or commonness of the measured features that may be useful for addressing questions about inferences of source.