Riso Error A16-525 -

This is a black velvet or non-reflective strip on the drum. If it is dirty, worn, or "too fuzzy," the sensor may reflect light back and incorrectly report that a master is still present.

Let’s break down exactly what this error means, what causes it, and the step-by-step methods to clear it for good.

Visually inspect the surface. If a master stencil is wrapped around it, manually open the clamp plate and gently peel the master away. riso error a16-525

If these steps do not resolve the error, it is possible that the or the Sensor Bracket itself is faulty and requires replacement. To help you narrow down the issue, I can:

: If the black fuzzy strip is coated in wet ink, clean it thoroughly. Wet ink reflects light, tricking the sensor. This is a black velvet or non-reflective strip on the drum

A used master may have wrapped around the disposal rollers, stuck to the compression plate, or failed to release from the print drum properly.

The causes of this error can be systematically categorized into three primary sources: media-related issues, mechanical wear, and sensor malfunction. The most common and simplest cause is the paper itself. Using paper that is too curled, too damp from humidity, or loaded above the fill line can prevent the feed rollers from establishing proper friction. Additionally, paper that is not perfectly fanned or has static cling can stick together, causing the sensor to see a gap instead of a sheet. The second category involves mechanical degradation. Over thousands of impressions, the rubber feed wheels (pick-up rollers) and the separation pad become smooth and glazed, losing their ability to grip and separate individual sheets. A broken or slipping belt driving the registration roller can also prevent paper from reaching the sensor. The third and most persistent cause is sensor contamination. The paper detection sensors are optical; they emit an infrared beam and measure its reflection. In a Riso duplicator, fine paper dust, ink mist, and spray powder inevitably accumulate on these sensors over time. When sensor 525 is coated with a layer of this residue, it becomes "blind," unable to detect the passing paper even when the mechanical feed is functioning perfectly, thereby triggering a false jam error. Visually inspect the surface

For a visual walkthrough on resolving common drum and master errors like A16-525, this video can help: Riso 3230 A16 525 error resolve Creator Ratikanta YouTube• Mar 30, 2023