Troubleshooting & Problem Resolution Flashcards

A lithographic press is showing excessive plate wear after only 50,000 impressions on what should be a 1,000,000-impression run. The most likely cause is:

Answer: Fountain solution pH too low, causing acidic etching of the plate surface

Fountain solution that is too acidic attacks and erodes the plate's image-bearing surface, drastically shortening plate life.

A wide-format print shows color shifts between passes on a multi-pass inkjet system. The technician has already confirmed ink density and substrate feed accuracy. The next item to check is:

Answer: Print head alignment and bi-directional calibration between forward and return passes

Color banding between passes on a multi-pass inkjet is commonly caused by misaligned print heads or incorrect bi-directional calibration causing offset dot placement.

After a substrate change to a coated board with a higher surface smoothness, a flexo press shows fill-in of fine reverses. The appropriate corrective action is:

Answer: Reduce impression pressure and switch to a lower-volume anilox roller

Smoother substrates require less impression pressure and lower anilox volume to prevent ink from filling in fine reverse details due to reduced mechanical resistance.

A quality control technician finds that measured ΔE values between proof and press are consistently high on cyan solids but acceptable on all other colors. The focused diagnostic step is to:

Answer: Check the cyan ink formulation against the target standard and verify the cyan curve in the ICC profile

A color deviation isolated to one channel points to either an ink formulation mismatch or an error in that channel's ICC profile curve, requiring targeted investigation of the cyan channel only.

A screen printer is experiencing ink bleeding under the stencil edge, causing loss of fine detail. After confirming ink viscosity is correct, what should be checked next?

Answer: Mesh tension — if too low, the mesh does not snap off the substrate cleanly

Low mesh tension prevents proper snap-off, keeping the mesh in contact with the substrate longer and allowing ink to bleed past the stencil edge.

A print provider is troubleshooting inconsistent gloss on a UV-coated sheet: some areas are high-gloss and others are matte. The most likely cause is:

Answer: Uneven UV coating weight caused by a worn or unevenly loaded coating roll

Gloss uniformity in UV coating depends on consistent coating film weight; a worn or poorly loaded coating roll deposits uneven amounts, creating high-gloss and low-gloss zones.

A print shop receives a complaint that spot color business cards vary in hue from run to run despite using the same Pantone mixing formula. The most overlooked variable is:

Answer: Ink draw-down on the current batch substrate prior to approving color at the beginning of each run

Substrate whiteness and surface characteristics affect how a spot color looks; always pulling a draw-down on the actual run substrate confirms color before press approval.