Laser printers are the most common and affordable printers today; they can handle a large volume of printing and are cheaper on the printing cost. Compared to an inkjet printer, the disadvantage of laser color printers is that they are more expensive than inkjet color printers, and due to the structure of the laser color printer, it is larger and heavier.
About the Laser Printer
The history of printing starts as early as 350BCE, and since the first woodblock printing in China around 200CE, our printing technology has developed into many advanced methods. The printing industry is important because it helps us to share knowledge and communicate.
In the modern world, we have developed new printing methods, through many printer types. They have their own advantages and disadvantages, so to understand the function of a printer can help you better choose the suitable one for your needs and to figure out a solution when dealing with defective printing.
How Does it work
First of all, the laser printer is based on the principle of electrophotography, which is the use of electrostatic force to pick up the toner powder and accurately deposit it on the paper.
The main component of a laser printer is the drum unit, a photoreceptor. It is made out of a metal cylinder and coating with a photoconductive material that can be charged by an electrical field and then parts of the surface and is discharged by a laser beam.
The image will be created on the drum surface by a charging and discharging process.
The laser printer requires 5 steps to complete a printing cycle
1. Charging the drum unit – The Drum surface is charged by the corona wire assembly or primary charge roller with negative electrostatic.
2. Exposure to light – In this step, the laser beam with a digital signal makes contact with the drum surface. The exposed area becomes conductive and discharges the drum surface (with positive electrostatic). An electric latent image is created on the drum surface.
3. Developing – It is converting the electric latent image into a visible toner image, the toner powder charged with negative electrostatic and brought closely to the drum surface. The positive charge surface will attract the negative toner powder on the surface. The visible toner image is created on the drum.
4. Image transfer – The drum rotates and makes contact with the positively charged paper, the toner powder will transfer onto the paper.
5. Fusing – The paper with a toner image delivers to a fuser section, the fuser is a heated roller and it melts the toner powder to fix it on the paper.
Also, printer cartridge is a consumable supply for a laser printer, different printer manufacturers have their own designs for printer cartridges for the particular print engine. Now the most major and popular printer manufacturers are Hewlett-Packard (HP), Canon, Brother and Lexmark. They have different designs on the printer cartridges, which can be separated into many parts, the major part is the drum cartridge and the toner cartridge.
About the Brand Printer
HP and Canon share the same print cartridge design, which includes all major parts of the electrophotography process. They make the drum and toner in the same cartridge. It is more user-friendly and customers only need to replace 1 consumable supply. But it will be more expensive for this design. Because HP and Canon are sharing the print cartridge design, some compatible cartridges for HP and Canon are universal for each other e.g. Canon 128 is universal with CE278A.
Brother designed a different structure on their printer cartridge, they separated the drum and the toner into 2 different cartridges. The advantage of this design is that the cartridge price becomes cheaper. But customers need to have the basic knowledge to understand what is the difference between a drum and a toner cartridge.
Moreover, Lexmark designed its printer cartridge for more high volume printing. Separating the printer cartridge into different parts. All major parts are separated. Customers most frequency need to replace the toner cartridge, it becomes a toner powder container only.
What is a Toner
The toner is a dry pigment powder with an 8-12 micrometre size. Normally the color laser printer needs four colors: Black, Cyan, Magenta and Yellow. The common and major ingredients for a toner are Polymer ( 70-90%), pigments e.g. carbon black ( 3-10%), Wax (5-15%) , Silica (<5%) and dioxide (<1%). Different toner formulas are to match the characteristics of the printer, e.g. the charging voltage, fuser temperature & toner color.
When you have the basic knowledge to know how a laser printer works. You can easily identify the problem of the laser printer and find the solution. Faded printing is the most common printing problem of a laser printer. A ghosted image on the printout, a vertical or horizontal line on the printout, full-page black or blank page printing.
For example, when you get the faded printing, the first reaction will be probably to assume that the toner levels are low. In fact, the wrong setting with the printer might cause faded printing . Especially when you use the compatible toner instead of an original toner. Most of the compatible toners were universal for all laser printers. The printing density might need to adjust when you use the compatible toner. Ghosted images on printouts are very often likely when the cartridge in which the drum and toner are separated. When the drum unit reaches its usable life cycle, it may not discharge properly and cause a ghosted image.