The “Aristocrat” of Printheads — Disassembly and Working-Principle Analysis of Kyocera Printheads

The “Aristocrat” of Printheads — Disassembly and Working-Principle Analysis of Kyocera Printheads

 

---

 

The “Aristocrat” Among Printheads

When it comes to Kyocera printheads, two features immediately stand out.
First is price: among all printheads of the same category, Kyocera printheads sit firmly at the top end of the market, often regarded as the “price ceiling.”
Second is extreme manufacturing precision: they feature very high machining accuracy, high jetting frequency, and outstanding print quality.

In today’s industrial printing sector, Kyocera printheads are widely used in high-end applications thanks to their exceptional stability and durability—despite their high cost. Currently, the Kyocera printheads available on the market mainly belong to two series: KJ4A and KJ4B.

• KJ4A series: Designed for oil-based inks, such as UV inks. These printheads are primarily used in advertising printing, pharmaceutical inkjet applications, and variable data printing for food and cigarette packaging.
  
  

• KJ4B series: Designed for water-based inks, such as reactive inks and disperse inks. They are mainly used in ceramic printing, digital textile printing, and flooring printing, with some applications also found in high-end corrugated carton printing.
  
  

 

---

 

Key Technical Highlights of Kyocera Printheads

Kyocera inkjet printheads adopt the Drop-on-Demand (DOD) principle using the Bend Mode actuation method. This approach fully leverages Kyocera’s expertise in fine ceramics, maximizing the advantages of high output power, high durability, and large-format piezoelectric ceramic actuators.

• Drop-on-Demand (DOD): A method in which ink droplets are ejected from the printhead only when required, based on image data.
  
  

• Bend Mode: A jetting mechanism in which ink is expelled by the bending deformation of a piezoelectric ceramic actuator caused by the piezoelectric effect.
  
  

Key advantages include:

• High-speed printing enabled by high-performance piezoelectric ceramic actuators manufactured with advanced fine-ceramic technologies
  
  

• Ink-channel designs that support large print widths and high resolution
  
  

• Stainless-steel laminated structures that ensure robustness and long-term stability in industrial environments
  
  

 

---

 

Ink Ejection Principle

Inkjet printheads are equipped with multiple nozzles capable of ejecting ink droplets. Independent internal ink channels precisely deliver ink to each nozzle.

The basic operating principle is as follows:

1. When a voltage is applied to the piezoelectric ceramic adjacent to the pressure chamber, the ceramic deforms.
   
   

2. The resulting change in the chamber volume generates a pressure wave that propagates toward the nozzle.
   
   

3. By synchronizing the deformation of the piezoelectric ceramic with the pressure wave, an ink droplet is ejected from the nozzle.
   
   

For a more detailed explanation of printhead technical specifications, please read the article: On-Demand Inkjet Technology: Piezoelectric Inkjet Technology (Pizeo)

---

 

Specifications of the Kyocera KJ4A Series

KJ4A Series (Oil-Based Inks)

The KJ4A series includes four different models, designed respectively for:

• Curved-surface printing
  
  

• Standard printing
  
  

• High-precision printing with small droplet sizes
  
  

• Dual-channel scanning applications
  
  

KJ4A-TA / KJ4A-RH Specifications

KJ4A-AA Specifications

KJ4A-0300 Specifications

While these models differ in parameters such as maximum firing frequency, maximum printing speed, and droplet size, they generally operate with similar ink viscosity and surface tension. Differences mainly lie in ink temperature requirements.

 

---

 

Specifications of the Kyocera KJ4B Series

KJ4B Series (Water-Based Inks)

The KJ4B series consists of eight models. Detailed model numbers and specifications are typically provided in technical reference tables.

KJ4B-0360 / KJ4C-0360 Specifications

KJ4B-QA / KJ4B-YH Specifications

KJ4B-0300 Specifications

KJ4B-1200 Specifications

KJ4B-0150 Specifications

KJ4B EX Series Specifications

In this analysis, we focus on the KJ4B-0300 printhead, which is one of the most widely used water-based inkjet printheads in the industry today. This model features:

• Dual ink channels
  
  

• High firing frequency
  
  

• High printing speed
  
  

• Relatively small droplet sizes for excellent print accuracy
  
  

Overall, it offers an excellent balance between speed and performance.

 

---

 

Printhead Disassembly

Internal Circuit Structure

The printhead consists of multiple internal circuit layers.

Multi-Layer Nozzle Plate Structure

As shown in the disassembly, this Kyocera printhead is composed of 11 nozzle plates, each containing 2,656 ink orifices. Ink is driven through every orifice in all 11 plates by the printing control system.

This design places extremely high demands on:

• Ink particle stability
  
  

• Ink viscosity consistency
  
  

• Lamination accuracy between nozzle plates
  
  

• The roundness and uniformity of each nozzle orifice
  
  

Under microscopic observation, the diameter of each nozzle hole is only about one-tenth the thickness of a human hair.

 

---

 

Ink Supply Principle

Structural Layers of the Nozzle Plates

• First nozzle plate layer: piezoelectric sensing layer
  
  

• Ink inlet and outlet nozzle plate layers
  
  

• Ink inlet and outlet holes in the nozzle plates
  
  

• Ultra-small ink reservoir nozzle plate layer
  
  

• Microscopic view of the ink reservoir
  

• Four main ink groove channels forming the primary ink pathway
  
  

Ink Supply Mechanism

As illustrated, the blank areas correspond to the internal grooves discussed during the disassembly—these grooves form the main ink channels inside the printhead. Ink flows into the grooves from one end and, when recirculation is enabled, exits from the opposite end.

At the top of each groove are fine ink channels that guide ink upward into an ultra-small ink reservoir beneath the piezoelectric actuator. When a jetting signal is received, the piezoelectric actuator bends according to the waveform’s timing and amplitude, compressing the ink in the reservoir and forcing it out through the nozzle.

The process shown above illustrates the deformation-driven ink ejection of Kyocera printheads under waveform control.

 

---

 

Summary
Kyocera printheads combine advanced fine-ceramic technology, precision mechanical design, and sophisticated ink-channel architecture. Their exceptional performance, durability, and print quality explain both their premium pricing and their dominant position in high-end industrial inkjet printing applications.