Business printers support users in busy workplaces such as offices and schools where the capability for high-speed printing is in particularly high demand. Improving paper handling speed and improvements in printhead technology are important factors in boosting printing speed up to 100 sheets per minute*1. The following introduces Epson's original high-speed paper handling technology.
For printing to take place, paper must be fed quickly and reliably from the paper cassette to under the printhead that ejects the ink. Paper is fed one sheet at a time between rollers and other components from the paper cassette up to the printhead. Precision control is required so that single thin sheets of paper are drawn into and discharged from minute gaps in the various mechanisms and fed without jamming
In the limited space inside the casing of a business printer, the paper path and mechanisms are complex. This means that advanced, high-speed paper handling technology and knowledge are required.
Warping of printed material that occurs as a result of the paper absorbing ink is an issue with high-speed inkjet printing. A variety of mechanisms and measures have been used to resolve this issue but roller feeding so far has had its limitations in high-speed printing of 100 sheets per minute.
Conventional feeding mechanism
When paper is fed by conventional systems, roller slipping sometimes causes paper to bend. A particular issue is that paper attitude cannot be controlled when it is not held between rollers. In this kind of state, the paper, for example, bumps against the rollers, and sometimes flaps around under the printhead. This can also result in distorted printed images, ink staining caused by paper coming into contact with the printhead, and printhead malfunctions.
(The figures below show the various ways paper comes into contact with the printhead.)
Electrostatic transport belt
To prevent the paper from rising up or bending, Epson has adopted high-speed paper handling technology that uses an electrostatic transport belt, which transports paper by the attraction of static electricity. By this mechanism, the belt is made to travel directly underneath the printhead and paper is carried on the belt. Also located in this configuration is a mechanism for charging and discharging static electricity from the belt.
The electrostatic transport belt is charged so that paper can be held in contact against the belt to prevent paper from flapping around even under the printhead. To ensure attraction capable of standing up to high-speed feeding, static electricity is discharged from the paper surface (printing surface) to increase attraction force.
Use of the electrostatic transport belt in this way eliminates paper rising up and bending during feeding and prevents contact between the paper and printhead. This reduces ink stains that occur as a result of ink adhering to the paper. Speed fluctuation during paper feeding is also reduced, improving printing quality. High-speed paper handling technology using the electrostatic transport belt helps achieve high-speed, high-quality printing.
*1: 100 sheets per minute for single-sided landscape view printing on an LX-10000F series A4 printer.