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Noise Reduction Technology

In recent years, office environments have become quieter, leading to the demand for quieter multifunction devices.
Multifunction devices contain many different noise sources, including multiple motors, fans, and sliding paper. Therefore, many different measures are necessary in order to reduce the sound of a multifunction device operating. Fuji Xerox has developed technology that decreases the amount of noise made by the automatic document feeder, the printing unit, and the finisher (Fig. 1).

Fig. 1: Technology implemented and the amount of noise reduction

Automatic paper transport unit with skew correction technology that decreases percussive noise caused by paper

Approximately 30 percent of the noise made by the automatic document feeder of previous models was made when adjusting the skew of a document before scanning it. This is because the skew was corrected by allowing the paper's front edge to run into a registration roll and pushing it forward, causing it to warp. This resulted in the paper making various percussive noises (Fig. 2-a).

To replace this mechanical skew correction system, Fuji Xerox has developed a new technology that utilizes image processing to correct the skew of documents, thus drastically reducing the amount of percussive noise that resulted from the previous skew correction process (Fig. 2-b). We have also developed a new dedicated semiconductor integrated circuit that makes this function possible. When a document is fed in at a tilt, the scanning unit reads that it is tilted. Next, the dedicated integrated circuit calculates the angle of the tilt and computes the skew amount. Then, using this calculated value, the document undergoes image processing to correct its skew. By reducing the amount of percussive noise caused by paper, this technology reduces the overall amount of noise resulting from the document scanning process (Fig. 2-c).

Fig. 2-a: The previous method (mechanical skew correction)

Fig. 2-b: The new method (skew correction using image processing)

Fig. 2-c: The area in which percussive noise caused by paper was reduced

In addition to this skew correction technology, we have also overhauled the driving system, paper transport components, and sound insulation. Because of this, in comparison to previous models,Note1 we were able to reduce the amount of noise made by the automatic document feeder of the new modelNote2 by as much as approximately 83 percent.

Quiet cooling technology (heat management)

By sealing the device's housing and adding sound insulation without sacrificing the functions that prevent the interior temperature of the device from rising, we were able to reduce the amount of noise made by the device, both when printing and when in standby mode.

The interior temperature of the device is prevented from rising with quiet cooling technology (heat management), which cools using heat diffusion and improved airflow (Fig. 3). The power supply unit, which generates a large amount of heat, has been moved away from the area near the print engine, where it was previously located, to the lower back area of the device. This distribution of heat sources to different locations, combined with the low torque marking technology explained below, has reduced the rise in temperature of the print engine area to just 1/3 of that of previous models. As a result of this, the cooling efficiency of the print engine has increased, allowing the air volume of the cooling fans to be reduced to approximately 1/3 of the previous amount, thus reducing the fan noise to approximately 1/3 of the previous amount as well (Fig. 4).

In addition, we also developed a new, more efficient cooling system for the power supply unit. In this system, heat from multiple sources is transferred to and collected in a single aluminum plate with a large surface area, which can be cooled by a single fan.

Fig. 3: A diagram of quiet cooling technology (heat management)

Fig. 4: A comparison of fan air volume and fan noise levels of the previous power supply unit
and the new power supply unit with heat transfer cooling

Low torque marking technology

When a multifunction device prints, the developer unit's magnet roll turns and generates frictional heat, which can cause the developer unit itself to heat up. To prevent this heat from damaging the toner inside, the developer unit in previous models was equipped with cooling fans. In order to suppress this rise in temperature of the developer unit, we altered the magnetism of the magnet roll, reducing the amount of friction generated between the roll and the developer. By doing so, we reduced the rise in temperature inside the developer unit to just 1/3 of that of previous models, enabling us to reduce the use of fans, thus reducing the amount of noise made by the machine.

Quiet finisher technology

The amount of noise made by the finisher during the initial settings process and when operating the stapler has been drastically reduced because of efficient operation, in which only the minimum amount of force necessary is used. We have reduced the amount of high frequency sounds and rattling noises to provide a quiet, comfortable environment.

We improved the design of the finisher's mechanisms and mechatronic components in order to reduce the sources of noise unique to the finisher (noise made by the stapler and compiler units, mechanical components and the drive mechanisms). We diminished the amount of noise made by the stapler by optimizing the stapling speed, using the minimum amount of force necessary according to the type of paper and number of sheets being stapled, and by preventing other parts of the finisher from moving when they are not needed. As an additional noise-reduction measure, we sealed the gaps between the finisher's covers, and the gaps where the finisher joins the printing unit, and made the paper exit openings as small as possible.

We were able to reduce the noise caused by mechanisms such as those of the compiler by optimizing their design parameters (e.g., speed parameters and the design of the rack used to align paper) using mechanism analysis simulations. Finally, we determined the most effective placement of sound-absorbing material using acoustic analysis in order to reduce the amount of drive noise escaping from the device openings.