Here is an introduction of how to check the image quality using the color charts.
| No. | Check Area | Check Item | Description |
|---|---|---|---|
| 1 | Frame line | Registration amount | Check the registration amount of the leading edge and trailing edge (sub scan direction). Overlay the chart and the copy, then check that the frame lines of the side [A] and leading edge [B] do not deviate. |
| Margin length | Check the margin length of the leading edge and trailing edge (sub scan direction). Overlay the chart and the copy, then check the erased length [A] (margin length). | ||
| Perpendicularity | Fold the paper, and check the deviation of the superimposed frame lines. If deviations in the main scan direction and sub scan direction are the same, it is a right angle.
1. Check the lengths between the leading edge and front end frame line at measuring positions [A] and [B]. 2. Check the lengths between the side edge and lateral frame line at measuring positions [C] and [D]. 3. Check the difference between 1 and 2. Example: 1: Right angle, correct feeding
| ||
| Linearity | Check the linearity with a scale. Check in both the main scan direction and sub scan direction. Overlay the scale on any frame line, adjust to a position where the frame line is not hidden, and measure the most distant position. If difficult to check, draw an auxiliary baseline in position with no distortion to the frame line, and measure the deviation length from the baseline with the scale. A: Measuring length, B: Base line, C:Copy If meandering, measure the maximum amplitude. If difficult to measure, draw an auxiliary baseline, measure the deviation length from the baseline with the scale, and sum it up. A: Measuring length, B: Base line, C:Copy | ||
| 2 | Cornfield pattern | Resolution | Check the number next to the finest set of lines that can be distinguished from each other clearly, and do not blur into each other. The intervals between lines in the chart are the following, in 15 steps. A higher number means a finer image (higher resolution). 2.0/2.2/2.5/2.8/3.2/3.6/4.0/4.5/5.0/5.6/6.3/7.1/8.0/9.0/10.0 [lines/mm] |
| 3 | Colored L-shaped lines | Color registration errors | Check the distances [A] between the colors making up the RGB lines (Y+M/ Y+C/ C+M), using a loupe. |
| 4 | Solid color patches | Solid density | Check the density of each color patch between the chart and the copy . |
| 5 | 13 gradations scale | Halftone density | Check that the density of each color patch in the 3rd row in the chart and the copy are the same. |
| Gray balance | Check that the K density of the 3rd and 5th rows in the chart and the copy are the same. | ||
| Gradation | On the copy, check that the densities of each color patch in the 11th and 12th rows are different. | ||
| Equal magnification (main scan direction) | Check that the magnification is equal in the chart and the copy using the scale under the gradation patches. The scale is 10mm per row. Check 10 consecutive rows. | ||
| 6 | Halftone area | Gray color difference | Check that the density in the chart and the copy is the same. There must be no unevenness in density between the front, rear, and middle. |
| 7 | Solid area | Solid filling | Check that there is no density unevenness in solid color. There should be no color unevenness in density between the front, rear, and middle. |
| 8 | Low contrast characters | Reproducibility of low contrast | Check that "C0.4" is readable in the copy when using the center notch (notch 5). In addition, "E0.2" must be deleted. |
| 9 | Six sizes of characters | Character reproducibility (no broken lines or blurred characters) | Check the minimum size of characters that are readable, and that have no broken lines or blurred characters. |
| 10 | Gray patches | Gray color difference and density | Check that the color and density of the 3rd row in the chart and the copy are the same. |
| 11 | Color patch | Color reproducibility | Check that the density of each color (KCMYRGB) in the chart and the copy are the same. |
| Color reproducibility of 2nd generation | Check that the density in the chart and a 2nd generation copy are the same. | ||
| 12 | Radial lines | Jagged slanting lines | Check that the lines in the copy are not rough or jagged. |
| Broken slanting lines | Check that the lines in the copy are not broken. | ||
| 13 | Color bold text | Solid color filling | Check that there is no missing color and no unevenness in RGB (YM/YC/CM) solid colors. |
| 14 | Color text | Color text reproduction | Check that the reproduced image is the same as the chart. The following diagram shows examples of errors. |
| 15 | Horizontal scale | Image position in the main scan direction (Whether the image is at the center of the paper) | In the copy, check the distance between the center line made by folding the paper and the line at the center of the chart. Trim pattern adjustment for each paper feed tray must be completed before checking.
A: Center line, B: Fold line, C: Distance between the center line and the fold line |
| 16 | Vertical scale | Equal magnification (Sub scan direction) | Check the magnification error in the sub scan direction using the crossed lines 100mm away from the leading and trailing edges of the paper |
| 17 | Lot number | - | Shows the lot number of the test chart. |
| 18 | Chart name | Reproduction of black characters | Check that the reproduced image is the same as the chart. |
| 19 | Portrait photograph | Reproducibility of the skin, hair, and clothes | Make a copy after setting the document type to photo mode, and check the reproducibility of the photo. Check the reproducibility of the granular state, and tone of color in the skin, hair, and clothes. Also check for overexposure and underexposure. |
| 20 | Landscape photograph | Reproducibility of sky blue | Make a copy after setting the document type to photo mode, and check the reproducibility of the photo. Check that the color tone of the chart and the copy are the same. |
| 21 | Notes | Check the reproducibility (for example, there should be no breaks in frame lines and characters). | Check the reproducibility, such as the presence of breaks in frame lines and characters. There is a place for writing down the output settings when you print the image samples and/or compare adjustments. |