How to solve the output graphic pale?
Posted by zhou on February 7th, 2018
The hp toner image on the drum surface is not rich and the test sample has a bottom ash. Note that the surface of the drum charge voltage is low or drum wear serious, to clean the charging electrode (charging roller). If it can not always be solved, check the high-voltage circuit, or replace a good high-voltage board to see if the fault disappears. Some models of high-voltage circuits and power control circuit is one, the method can be used to measure the boost components, inspection, repair.
When the above checks are in good condition, check whether the magnetic roller has a bias voltage and the magnetic roller bias is not normal. Adjust the print density knob to observe whether there is any change of the powder carbon image on the photosensitive drum. hp cf230a toner images have changed, indicating that there is a development bias. Powder carbon image no change, may be adjustable potentiometer bad contact or no magnetic roller bias, then you can clean or repair the concentration adjustment potentiometer, you can solve the problem.
If both the charging voltage and the magnetic roller bias are normal, the toner image on the drum surface is light and check if the laser drive current is reduced. Clean the lenses and mirrors in the module first. Because of the contamination of the above components, the penetration and reflectivity of the light beam will be weakened, resulting in underexposure. After cleaning, if the toner image is still light, check whether the contact area of the drum is bad. Because it is not completely dissipated, a small potential difference results in a lack of capacity to attract toner. If the negative electrode contact is good, it may be laser aging or laser beam current is low. Maintenance method is to open the scanning components, the appropriate adjustment of laser beam current. Note that high-speed laser beam current may accelerate the laser aging or damage (except for changes in the laser beam current line component changes), if you are not familiar with this, must not be arbitrary, should be adjusted by an experienced maintenance instructor, Another note, can not be adjusted too large.
After the above check is correct, if the toner image on the drum surface is normal, and the test sample is not enough toner concentration, it is certainly the transfer of low electric field caused. Check the transfer electrode (transfer roller) is dirty or poor contact, and cleaning. If the wire transfer model, should check the location of the electrode wire is correct. If the above parts are normal, then check the transfer voltage generating circuit and check.
