Inkjet Printing DPI: Resolution Requirements for Different Applications

DPI, or “dots per inch,” is a measurement that communicates how many dots are printed within one inch of an image. The higher your DPI settings are, the more ink is used to create an image, message, or barcode. In other words, printed images look sharper and more defined when they are printed at a higher DPI. 

In the product coding and marking industry, DPI is an essential consideration. Different applications carry their own DPI requirements in order to succeed. For example, date codes and lot codes can be printed at low resolutions and still be legible to the human eye. Machine-scannable barcodes and QR codes, on the other hand, must be printed at a higher level to guarantee scannability. 

Most product coding, “primary packaging” is completed using continuous inkjet (CIJ) and thermal inkjet (TIJ) printers. Both of these inkjet printer types utilize very different operating mechanisms that affect their DPI capabilities. Moreover, DPI capabilities can vary significantly between specific printer models as well. 

If you have questions about inkjet printing DPI, you’ve come to the right place. Below, we explore the DPI requirements of different code applications, examine the DPI capabilities of CIJ and TIJ printers, and describe which options are right for certain situations. 

Recommended DPI Settings for Codes, Text, and Images

DPI settings affect the quality of every code, text, and image that you produce. While other factors—such as image size and ink choice—will also influence the final appearance of your markings, it’s important to understand the DPI best practices for your applications. 

Alphanumeric markings (e.g., text messages, date codes, lot codes, etc.) can often be created at very low DPI ratings. These messages are not scanned by machines and generally serve utilitarian purposes such as aiding traceability or communicating expiration dates, so aesthetics are not a prime concern. With low DPI settings, line operators can print alphanumeric markings on high-speed production lines for maximum productivity. 

Compared to alphanumeric ratings, machine-scannable markings require higher DPI levels to guarantee scannability. When printed as small images, QR codes can be printed at around 50 DPI and achieve scannability. However, if you enlarge a QR code without raising the DPI, you risk creating an unscannable marking due to the low resolution. Consequently, it’s important to test your codes as you adjust your settings. 

Like QR codes, barcodes must be machine-scannable. While QR codes can be printed in small sizes, barcodes are often larger, reaching heights around ¾ of an inch. At sizes above ¾ inch, barcodes should be printed with levels around 200 DPI or higher.

Inkjet Printing DPI: The Capabilities of Different Technologies and Printer Models

With the above best practices in mind, we can now examine the DPI capabilities of today’s inkjet printers. Inkjet printing DPI varies between printer types and models, so it’s important to understand the specifications of different printing technologies before investing in a system.

Continuous inkjet printers like the DuraCode Touchscreen and DuraCode Keyboard specialize in industrial product coding. CIJ printers internally pressurize ink in a circular fashion to enable uninterrupted operation for up to 24 hours a day. Many companies capitalize on these abilities by running CIJ printers on high-speed production lines. CIJ printers can complete low-resolution coding applications at speeds above 300 m/min, making them ideal for high-volume operations involved in:

CIJ printers are also capable of creating machine-scannable QR codes but only at small sizes due to limited DPI capabilities (most CIJ printers print at levels lower than 75 DPI). This DPI range also limits how well CIJ printers can create barcodes and graphics. For these applications, a thermal inkjet printer will likely be a better option. 

TIJ printers have greater DPI resolutions than CIJ printers but have slower marking speeds. While DuraCode printers offer a max speed of 320 m/min, most TIJ printers max out around 80-120 m/min. High-end TIJ models like the Anser X1 are the exception, as they can print at speeds around 300 m/min. 

TIJ printers like the Anser A1 and Anser X1 can create markings up to two inch high at 600 x 600 DPI. These capabilities make TIJ printers ideal for creating high-quality barcodes, images, and complex company logos. Depending on the material compatibility of the printer model, you can also use TIJ printers to mark secondary packaging as well—an application usually completed by high-resolution case coders.  

In addition to these options, laser marking systems can be used to complete diverse coding applications. Fiber, CO2, UV, and LDR laser systems are all capable of high-speed alphanumeric coding as well as more intricate applications such as barcoding and high-quality image marking. Moreover, laser systems can perform these applications on both moving and stationary materials—an option that no inkjet printer can offer. 

Need Helping Finding the Perfect Printing Solution? InkJet, Inc. is Here to Help

All code applications require a certain DPI level to be successful. While some codes do not require significant contrast to be legible (e.g., date codes, variable data text, etc.), QR codes, barcodes, and other machine-scannable markings must be printed with a high enough DPI level to ensure scannability. If you are unsure of which printer is right for your applications, InkJet, Inc. can help you find the best solution for your needs.

From industrial-speed CIJ printers to DPI-rich TIJ printers and high-resolution case coders, InkJet, Inc. carries printing solutions for companies of all sizes and industries. Contact us today to learn which technology is right for you.

For more information about Inkjet printing DPI and other industrial marking topics, contact InkJet, Inc. online or call 1(800) 280-3245.