Ink cups for pad printing machines come in a variety of forms and styles. Looking at the market over the past few years, the biggest change in equipment design and implementation has been the increased use of sealed cup (closed ink cup) systems over open inkwell doctor blade systems. This is especially true in the US market, where sealed cup systems have dominated new pad printing equipment purchases for several years; however, open inkwell systems are still in use throughout the world. Both types of inking systems have a great deal of features, and new-equipment buyers often ask how one system compares to another.

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What is the Doctor Blade (Open Inkwell) System?

A doctor blade system has an open reservoir of ink from which a flood bar draws ink onto a printing plate, and a sharp blade called a “doctor blade” wipes the plate clean. With this system, the ink is exposed to the air and therefore enables the pad printing ink solvents to evaporate, which slowly changes the viscosity of the ink. Several pad printing machines have attempted to create “covered” inkwells to limit the evaporation, but the ink reservoir is still exposed to the air, and the ink’s consistency still changes.

What is the Sealed Cup (Closed Ink Cup) System?

A sealed cup system is one that involves the use of an inverted cup that is filled with ink, and the sharp rim of that cup is used as a printing plate wiping system. The sealed cup system floods and “doctors” (or “wipes”) a printing plate in the same motion, dramatically limiting the ink exposure to the air, thereby limiting solvent evaporation and ink viscosity changes.

How Do Different Ink Cup Systems Handle Long Images?

A significant advantage of the doctor blade system over the sealed cup system is that it can easily print long images, as there are fewer constraints on the width of the doctor blade or plate.. Long images on plastic housings like a television, computer monitor, or vacuum cleaner are primarily done using doctor blade machines.

However, recent developments with ink cup pad printing technology have made long-image printing possible with the consistency of a sealed cup. A slide system can be mounted to the pad printing machine that sweeps the cup from side-to-side (instead of front/back) across the length of the image. This system is generally referred to as “transverse doctoring”, and it works extremely well for mid-quality images and has been the printing method of choice for printing on specialized medical equipment like catheters.

Sealed Ink Cups for Pad Printing: The Industry Standard

Sealed ink cups for pad printing machines have become the industry standard, and for good reason. By limiting solvent evaporation from the ink, the skill level involved in maintaining the chemical balance of the ink is reduced, and the process becomes much more predictable and manageable. Using this technology, less experienced operators can now run the pad printing machines more efficiently.

The two main drawbacks to sealed cup systems vs. doctor blade systems are the unit cost of ink cups & ceramic doctoring rings and the high costs incurred when printing very large or long images. The cost becomes particularly expensive when supplies are purchased directly from the manufacturers of the pad printing machines.

Having extra ink cups with pre-mixed ink ready to insert while others are being cleaned on the side is an efficient way to minimize that cost impact. Beyond these concerns, see our for a full breakdown of what you need to get started.

Closed Ink Cup vs. Open Inkwell: A Side-by-Side Comparison

Choosing between a closed ink cup system and an open inkwell (doctor blade) system for pad printing can be one of the first equipment decisions that a print shop makes. Both systems have been proven over decades of industrial use, but here is a direct comparison of where the technology currently stands:

Comparison Point	Closed Ink Cup Sealed Cup	Open Inkwell Doctor Blade
Ink Application Method	Inverted cup with ceramic or carbide ring floods and doctors the plate in a single motion.	Open ink reservoir uses a flood bar and a doctor blade as separate components.
Air Exposure Levels	Ink is shielded from air. Minimal solvent evaporation occurs and viscosity remains stable. More predictable results.	Ink is exposed to air. Exposed solvents evaporate over time, requiring more frequent viscosity adjustments.
Recommended Operator Skill Level	Lower operator skill required to maintain consistent ink chemistry.	More experienced operators needed to manage ink viscosity and blade adjustment.
Regional Popularity	Dominant in North America and growing globally. Recognized as the industry standard for new equipment purchases.	Still widely used globally, particularly in Europe and Asia, and also used for long-image applications.
Unique Costs and Considerations	Cups and ceramic rings add per-run consumable cost; large-image printing has size limits.	No cup/ring consumable cost; handles virtually unlimited image widths with standard doctor blades.
Recommended Applications	Best for short-to-medium runs, multi-color, promotional products, medical, apparel/tagless.	Best for long images, TV housings, vacuum cleaners, golf balls, plastic molding, and long-run jobs.

For a deeper dive into how each system works within the full pad printing process, visit the Inkcups Pad Printing 101 Guide. For setup tips on loading ink cups for pad printing machines, see: How to Load Plates and Ink Cups into a Pad Printing Machine.

Ceramic (Zirconia) vs. Tungsten Carbide Doctor Rings for Pad Printing

The market for pad printing ink cups and rings originally started with carbide steel doctor rings. The ceramic ring was introduced to the US market in 1993 and has since been extremely successful. Today, the market is roughly evenly split between tungsten carbide and the newer generation of ceramic doctor rings.

It is our opinion that the ceramic doctor ring offers several advantages. The ceramic ring has self-lubricating qualities that make it work equally well on thin steel, thick steel, and softer polymer printing plates. Carbide rings are generally sharp and abrasive and will wear a polymer plate quickly. The ceramic ring is also generally thicker, more robust, and more resistant to handling damage.

With all that said, both setups have been proven for different applications over decades of industrial use. Here is a side-by-side comparison:

Comparison Point	Ceramic (Zirconia) Ring	Tungsten Carbide Ring
Recommended Plate Material	Self-lubricating properties work equally well on thin steel, thick steel, and softer photopolymer plates.	Extremely sharp and abrasive. Excellent on hard steel plates but accelerates wear on photopolymer plates.
Average Ring Thickness	Thicker cross-section (~0.006″) with taper from both inside and outside diameter. More material near the tip.	Thinner cross-section (~0.003″) with taper from outside diameter only. Minimal material near the tip makes it brittle.
Equipment Resilience	Highly resistant to handling damage. More durable in day-to-day production environments.	Prone to chipping or cracking during normal operator handling due to brittle nature of carbide.
Compatibility with Photopolymer Plates	Does not damage photopolymer plates. Extends plate life significantly.	Not recommended for use with photopolymer plates; wears plate material quickly.
Double-Sided vs Single-Sided	Available double-sided. Flip the ring to double the usable life without replacement.	Typically single-sided. Once the edge is worn, the ring must be replaced.

Browse all our available ink cups and rings available for pad printing here.

Magnetic vs. Non-Magnetic Ink Cups for Pad Printing

Nearly all sealed ink cup types for pad printers fall into one of two categories: magnetic or non-magnetic cups. Both deliver clean, properly doctored plates when used correctly, but each has a distinct performance niche:

Comparison Point	Magnetic Ink Cups	Non-Magnetic Ink Cups
Pressure Application Method	Self-doctoring via powerful magnets. The cup provides its own downforce to clean the plate.	Pressure applied by the machine to an outer flange or centering hole via a spring-loaded system.
Color Compatibility	Ideal for multi-color pad printing applications. Simpler machine construction reduces equipment cost.	Best suited for compact or high-speed single-color applications where the spring-loaded hold-down keeps the cup firmly in place at high cycles.
Machine Compatibility	VersaCup® (patented 2003) is a universal magnetic ink cup compatible with nearly every sealed cup pad printing machine brand on the market.	Spring-loaded systems are very compact and effective but are more complex to deploy across multi-color setups.
Applicator Placement & Setup	Encapsulated magnet design reduces ink changeover time and eliminates plate damage from loose or flaking magnets.	Typically more precise cup positioning in high-speed applications where consistent plate contact is critical.

Benefits of VersaCup ® Ink Cups

The VersaCup ® by InkCups is the most widely adopted universal ink cup for pad printing on the market, known for reducing inventory costs, simplifying changeovers, and improving operating margins for printers. Some features of the VersaCup ® include:

Lower costs for both ink cups and ceramic rings
Damaged ceramic rings can be easily removed, flipped over or quickly replaced on site
Two-sided ceramic rings have double the life than single-sided rings
Low-profile design prolongs ink life and reduces ink waste
Ceramic rings are more robust than brittle steel rings and are less prone to damage
Ceramic rings extend polymer plate life
“Encapsulated” magnets reduce time for ink changeover and eliminate plate damage from loose or flaking magnets

Inkcups’ patented VersaCup® is a magnetic ink cup that fits all popular pad printing machine brands, including:

Overall, the pad printing marketplace has become relatively mature over the last decade, and the quality of the products available in the marketplace is very high, so regardless of the type of pad printing machine, doctor blade vs sealed cup system, or ceramic vs carbide rings, you are bound to have a highly successful experience with pad-transfer printing.

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