Frequently Asked Questions


Thermal Transfer Printing 101

Thermal printing is a printing method that involves using a heating element at the tip of a thermal printhead. It is used in a variety of applications, including product labels, bar codes, and receipts issued by supermarkets. Notably, there are two primary types of thermal printing—direct thermal and thermal transfer.


Direct thermal printing applies heat directly to the thermal paper, which then records the image.


Thermal transfer printing, on the other hand, heats the marking foil and transfers the image to the object.

Furthermore, there are two different types of thermal transfer printing—a melting type that uses the ink melt generated by heating and a sublimination type that turns the ink into gas by heating. Thermal transfer printing is also called “wax printing” or “image printing.”


Apart from this, there are three types of marking foils used by thermal transfer printers: wax-based ribbons, resin-based ribbons, and wax-resin type.


While wax-based ribbons have a relatively low ink melting temperature, resin-based marking foils have a higher melting temperature (relative to wax-based type) and are more resistant to heat, abrasion, and chemicals. As a result, prints produced by the latter are more suitable for long-term storage purposes.


Meanwhile, wax-resin type inks possess the characteristics of both wax and resin types. Therefore, customers can select the ratio of wax to resin that best fits their desired application.



Types of Thermal Printing


The advantages and disadvantages of direct thermal and thermal transfer printing are presented below.

Direct Thermal Printing

Direct thermal printing uses a thermal printhead that heats the thermal paper directly on contact.

Thermal paper is a special type of paper that develops color when heat is applied to its surface.


It is widely used by monochrome mobile label printers to print barcodes/prices of merchandise and by fax machines.


Since thermal paper itself develops colors, ink is not necessary in direct thermal printing.

Effectively, this eliminates the need to purchase ink on a regular basis, thereby reducing running costs.


Direct thermal printing can print only on thermal paper, which has low weather resistance (relative to other methods of printing), and its colors tend to fade over time.

This may limit the use of direct thermal printers for indoor and short-term labels and receipts.


Moreover, the printing colors are limited to black, dark blue, or sepia. Since thermal paper reacts to frictional heat, simply rubbing the paper ends up generating color on it.

Thermal Transfer Printing


Thermal transfer printing is conducted by applying a thermal printhead to a film-like marking foil for heating specific areas.


This activates the heated area of the marking foil, causing the ink to migrate to the object and adhere to it. The melting type thermal transfer printing prints by melting ink, while the sublimation type prints by turning the ink into gas.


The advantages of thermal transfer printers over direct thermal printers include the availability of marking foils in a wider range of colors, the ability to print on non-thermal papers (e.g., general paper and resin), and more flexibility in terms of printable materials.


Furthermore, since they are more weather-resistant than direct thermal printers, they are more suitable for outdoor or long-term use cases.


Thermal transfer printing uses consumables, such as marking foils, that needs to be purchased periodically.


Moreover, thermal transfer printers are bigger in size than direct thermal printers, since they involve the use of more components, such as the marking foil.



While thermal transfer printers can print on flat, fine-surfaced paper and resin, they cannot print on fabrics with rough surfaces.


The thermal transfer paper used for direct thermal transfer printing is composed of a base material and a thermal layer.


The thermal layer contains a color developer and a leuco dye, which are mixed by the application of heat to produce color.



Thermal transfer printing can be used on plastic materials, such as packaging films and labels.


CTK offers a line of printers for printing on plastic marker tubes, marker plates, and marker labels to identify wirings.



CTK's thermal printheads have 8 heating elements per 1 mm of width (each element is 0.125 mm long) that are aligned in a 40 mm straight line.


While thermal printheads adhere to the object while printing, fiber materials are coarser than the length of the heating elements per unit.


Therefore, it does not adhere adequately and, therefore, is not suitable for thermal printers.

The hot stamping method is more suitable for such textile printing purposes.


Durability of Thermal Print


The weather resistance test is a significant metric that can be used to accurately evaluate printing. This test examines the time taken for printed characters to fade after being exposed to ultraviolet light or water spray.


While this test can simply be conducted by exposing prints to the air, this process may take several years to complete. Therefore, a dedicated machine is used to accelerate this deterioration and then evaluate the results within a shorter period of time.


In this context, all genuine CTK Hotmarker consumables have been subjected to JIS(Japan Industrial Standards)-based accelerated weathering tests to ensure that they meet in-house durability standards.

Components of Thermal Transfer Printers


The following are the main components of CTK’s thermal transfer printers.




Thermal Printhead

The thermal printhead is a key component that comprises a heat-generating element at its end, which heats the marking foil to transfer images onto the object.
The thermal printhead of CTK’s SP series is divided into three sections, where each section can be used one at a time.


Thus, when a phenomenon known as "dot loss" (i.e., when some part of the print is missing from the object) occurs after a printer has been used for a prolonged period of time, the user can switch to employing the unused section of the thermal printhead.

Thermal printhead

In this way, the usable life of the thermal printhead becomes three times longer than when the whole section is used at once.

While the design life of a thermal printhead under ideal conditions is about 10 km, our design prolongs it by three times (i.e., 30 km or 10 km x 3).

Foil Supplying Spindle

The foil supplying spindle is a reel that is used to set and feed the marking foil.


Therefore, this function ensures proper feeding of the marking foil.

Foil supplying spindle

Work Driving Rollers

Work driving rollers carry out the responsibility of transferring the object accurately so that it synchronizes with the marking time of the thermal printhead.

Work driving rollers

Platen Roller

The platen roller is a key component that supports the work situated below the thermal printhead.


It rotates and transfers the work forward after each round of printing. It should be noted that the platen roller tends to wear out after prolonged use, thus resulting in poor printing quality over time.

Therefore, it needs to be replaced periodically.

Platen roller

Foil Rewinding Spindle

The foil rewinding spindle refers to the mechanism used to wind up the utilized marking foil.

Foil rewinding spindle

Foil End Sensor

The foil end sensor detects the moment when the marking foil is completely used up.

Foil end sensor

Work End Sensor

This sensor detects when the object has run out and needs to be replaced.


When it detects such a situation, it sends an error message and stops printing, similar to how a foil end sensor operates.

Work end sensor

Foil Full Sensor

The foil full sensor detects when the foil rewinding spindle is completely filled with the used marking foil.

Foil full sensor

Comparison with Similar Technologies


Thermal Transfer Printing vs. Inkjet Printing

In inkjet printing, ink particles ejected from a nozzle are deflected by an electrode and sprayed onto the printing surface.


Unlike thermal printers, these printers can carry out printing without direct contact. Hence, they can be used to print on objects of all shapes and sizes, such as film, PET bottles, and cans for packaging.


However, thermal transfer printing is more environmentally friendly than inkjet printing because it uses inks containing organic solvents that release only a small amount of environmentally hazardous substances into the air when it dries.


Thermal Transfer Printing vs. Hot Stamping

Another reason why thermal transfer printing is more advantageous than inkjet printers is that the latter requires the cleaning of ink tanks and nozzles after each color change, while color changes in the former can be easily achieved by simply replacing the marking foil.


Hot stamping, in which the type is pressed directly onto the substrate, enables simultaneous printing and engraving, resulting in highly durable printing. However, in this case, the type needs to be replaced every time the printing content is changed.

hot stamping

In contrast, thermal transfer printing can be set up using keyboard inputs or through a PC. Hence, no time is expended on carrying out the preparations for printing.


Thermal Transfer Printing vs. Laser Printing

In the laser printing method, a laser beam amplified by an oscillator is irradiated onto the object, thus enabling non-contact printing similar to inkjet printing. In addition, since marking foils are not used in laser printing, the cost of consumables can be reduced.


On the other hand, laser printers suffer from disadvantages such as high installation costs, time-consuming focal length setting of the laser beam, the fact that only oxidized colors of the printing piece can be printed, and the environmental impact of combustion gas emissions during oxidation.

laser printing

In comparison, thermal transfer printers have many advantages.

How to Choose a Thermal Transfer Printer


When choosing a thermal printer, the following key factors should be considered:

1. Processing capacity and production volume

Processing capacity is expressed in terms of the distance processed per second.


The processing capacity of CTK thermal printers is 27mm/sec (SP8600).

2. Total cost

In addition to the initial cost of purchasing the equipment, one should also consider that running costs will be incurred while operating the machine.


These costs include expenditures on consumables, such as marking foils, and replacement of components (such as spindles) that may occur when the machine remains in use for prolonged periods. marking foil. Therefore, estimating the total cost must include both the initial cost and the running costs.

3. Shape of works

Product specifications vary depending on the type of work. CTK's SP series thermal printers can handle three types of work: marker tubes, marker labels, and marker plates (terminal nameplates).


Furthermore, the SP series printers can print on marker tubes with non-planar shapes by flattening the marker tube using the press roller that comes equipped with this series of printers.


Our Products

CTK offers three models of mark tube printers that serve wiring identification purposes. While the SP8501 is the standard model, the SP8801 is a high-end model that can print materials with broader widths.


In addition, the latter is equipped with the function to cut a mark tube into pieces and then align and paste them onto a tape (the SP8501 and SP8801 are models primarily made for the Japan domestic market and, thus, are not CE compatible).

The third model is the SP8600, which is compatible with CE markings.


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