Canon MF657Cdw / MF655Cdw / MF651Cw: Poor Scan Quality on a PC When Using MF Scan Utility

Last Updated on 16.04.2026 by DriverNew

Applies to models: Canon MF657Cdw, MF655Cdw, MF651Cw.

If a document scanned to a computer through MF Scan Utility looks worse than when it is sent by e-mail, scanned through the mobile app, or captured using another scanning method, this does not necessarily mean the multifunction printer is faulty. In most cases, the issue is caused by the wrong scan profile being selected for scanning to a PC, or by image processing settings that are not well suited to the original.

How the problem usually appears

• when scanning through MF Scan Utility, the background looks too dark, tinted, or “dirty”;
• text looks less sharp than expected;
• quality is better through the Canon mobile app or scan to e-mail than on a PC;
• with the same original, the result changes depending on how the scan is started.

Why this happens

In MF Scan Utility, Canon uses different presets for different tasks. On the main screen, there are buttons such as [Document], [Photo], [Custom], and [ScanGear]. Canon explicitly states that [Document] is intended for documents containing text and diagrams, while [Photo] is intended for photographs. If an unsuitable mode is used for a normal paper document, the result may be worse than when scanning in another way.

In addition, the [Settings] window in MF Scan Utility has its own options, including [Color Mode], [Resolution], [Paper Size], [Document Scan Orientation Settings], and [Image Processing Settings]. Canon also separately describes scan enhancement features for the MF650 series itself, including <Original Type>, <Density>, and <Sharpness>. This means scan quality can genuinely depend heavily on the selected mode and settings, not just on the scanner hardware.

Where to start

1. For testing, use the same document throughout.
2. Compare the result:
   • through MF Scan Utility on a PC;
   • through another method, if available, such as scan to e-mail or the mobile app.
3. If the problem appears only on the PC, then the next step is to check the MF Scan Utility settings rather than looking for a hardware failure.

This exact scenario has already been reported by owners of this series: for the MF657Cdw, one user described scan to e-mail and the mobile app producing good results, while scanning to PDF through MF Scan Utility on Windows produced a blue background. This is a useful real-world clue: if one scanning method produces a good result and another does not, the problem is usually in the settings of that specific scanning method.

https://community.usa.canon.com/t5/Office-Printers/Poor-scan-quality-Canon-i-SENSYS-MF657Cdw/td-p/440051

Step 1. For normal documents, use [Document], not [Photo]

Canon explicitly states that the [Document] button is suitable for scanning documents containing text and diagrams, while [Photo] is intended for photographs. For contracts, instructions, invoices, forms, statements, and similar paper documents, it makes more sense to start with [Document].

1. Open MF Scan Utility.
2. For testing, use the [Document] button.
3. Do not compare quality using [Photo] for a normal text-based original.

Step 2. Open [Settings] and check [Color Mode]

In the [Settings] window, Canon separately describes the [Color Mode] option. This setting controls how colors are scanned. For text originals, the selected mode directly affects background appearance, contrast, and text readability. Canon explains that [Black and White] is suitable for originals with a lot of text and line drawings, while [Grayscale] is suitable for photographs and similar images.

1. In MF Scan Utility, click [Settings].
2. Open the profile you normally use.
3. Find [Color Mode].
4. For a normal text document, try:
   • [Black and White] if you want maximum text contrast;
   • [Grayscale] if too much detail is lost in black-and-white mode.
5. Run another test scan.

If the document on the PC looked “blue,” “gray,” or had an unwanted colored background, this step is often the first one that helps.

Step 3. Check [Resolution]

Canon also separately highlights the [Resolution] setting in the [Settings] window. Resolution that is too low reduces text readability, while resolution that is too high makes the file larger and can sometimes emphasize background noise more than necessary.

1. In the [Settings] window, find [Resolution].
2. For most text documents, start with 300 dpi.
3. If the document has very small print or is poorly printed, try a higher value.
4. If the problem is a “dirty” background or an excessively large PDF, do not raise the resolution unnecessarily.

Step 4. Check [Image Processing Settings]

In MF Scan Utility, Canon also provides a separate [Image Processing Settings] section. It includes at least three useful options:

• [Sharpen outline] — emphasizes image contours to make them look sharper;
• [Correct black text] — makes the contours of black text clearer;
• [Reduce moire] — reduces moire patterns and striping.

1. In the [Settings] window, find [Image Processing Settings].
2. For text documents, first try enabling [Correct black text].
3. If the text looks soft or blurry, check [Sharpen outline].
4. If you are scanning a document from a magazine, brochure, or a source with halftone illustrations, try [Reduce moire].
5. After each change, run a new test scan using the same sheet.

Step 5. If the result differs between the feeder and the platen glass, check [Scanning Method], [Paper Size], and [Document Scan Orientation Settings]

Canon states that in MF Scan Utility, quality and scan results also depend on [Scanning Method], [Paper Size], and [Document Scan Orientation Settings]. For example, if the document is scanned from the feeder but the program expects a different source or a different paper size, the result may differ from what you expect.

1. In the [Settings] window, check [Scanning Method].
2. Make sure the correct source is selected: the feeder or the platen glass.
3. Check [Paper Size]. For a normal A4 sheet, it is better to specify A4 explicitly instead of relying on automatic detection.
4. Check [Document Scan Orientation Settings] if you are using the feeder.

If you are comparing scan quality from the platen glass and from the ADF, make sure the software is not treating them as two different workflows with different settings.

Step 6. If the standard profiles are not enough, use [ScanGear]

Canon describes the [ScanGear] button as the entry point to the scanner driver screen where you can adjust scan parameters. This is the correct path if the standard [Document] and [Photo] profiles do not produce the result you need.

1. Open MF Scan Utility.
2. Click [ScanGear].
3. Review the advanced scan settings.
4. Run a test scan and compare the result with the normal profile.

This step is especially useful if you do not need a general office-document profile, but a more precise manual setup.

Step 7. For scan to e-mail and scan to folder, use <Original Type>, <Density>, and <Sharpness> on the device panel

For the MF650 series itself, Canon separately describes a section for clearer scanning. In it, you can adjust <Original Type>, <Density>, and <Sharpness> for sending by e-mail, Internet fax, or saving to a server. Canon explicitly states that density can be adjusted if text or images are too light or too dark, and sharpness can be increased for blurred text and pencil lines or reduced for magazine photographs.

This point is important to interpret correctly: if scan to e-mail or scan to folder gives good results, but scanning to a PC through MF Scan Utility gives poor results, the cause is often not the hardware, but the difference between settings on the device panel and settings in the computer software.

Step 8. If you do not want to save poor results blindly, enable [Check scan results]

Canon also documents the [Check scan results] option. It lets you view thumbnails before saving and, if necessary, change the data format, image order, and other parameters. This is useful while you are still fine-tuning settings and do not want to save a poor result every time.

1. In MF Scan Utility, click [Settings].
2. For the profile you need, enable [Check scan results].
3. After the test scan, review the result before final saving.

How to quickly tell where the problem is

• If quality is normal through scan to e-mail or the mobile app, but poor on the PC — the problem is usually in the MF Scan Utility profile, not in the scanner itself.
• If a normal paper document is scanned with [Photo] — the result may be worse than with [Document].
• If the text looks gray, unclear, or the background is too visible — first check [Color Mode], [Resolution], and [Correct black text].
• If the problem appears only when scanning through the ADF — also check [Scanning Method], [Paper Size], and [Document Scan Orientation Settings].

When to contact support

• you have already checked the [Document] profile;
• you have adjusted [Color Mode] and [Resolution];
• you have checked [Image Processing Settings];
• you compared the result from the platen glass and the feeder;
• you tried scanning through [ScanGear];
• the quality still remains clearly incorrect.

If the result remains poor only on the PC after these checks, it makes sense to contact Canon support and clearly describe how the quality differs between MF Scan Utility and other scanning methods.

Brief conclusion

For the Canon MF657Cdw, MF655Cdw, and MF651Cw, poor scan quality on a PC when using MF Scan Utility is most often caused not by a hardware problem, but by the selected profile and image processing settings. First, check whether [Document] is being used, then review [Color Mode], [Resolution], and [Image Processing Settings], and if needed switch to [ScanGear] for more precise adjustment. If other scanning methods produce better results, the issue is usually solved through settings rather than repair.