Preventive Maintenance for Komori Printing Presses

Think about the human body for a moment. Someone who pays attention to preventive medicine and looks after their health has a better chance of staying free of illness, living longer, and enjoying an easier life. A printing press behaves in much the same way. When a press runs without breakdowns, output rises, quality stays steady, and the machine serves the shop for more years. The problem is that most press repairs happen only after a breakdown, once the machine has already stopped producing. Repair at that stage costs time, costs money, and disrupts the schedule.

Few print shops follow a planned maintenance routine. A planned cycle of inspection and monitoring, carried out before parts fail, is far cheaper than emergency repair. There is one important difference between a body and a machine. The body can rebalance itself, adjust, and recover. With regular checkups, better daily habits, and the right medication, a person can return to good health. A machine has no such self-repair. Unless worn parts are replaced or adjusted, the condition only gets worse until the press cannot be used at all.

What KPM Means for a Print Shop

Komori Preventive Maintenance, usually shortened to KPM, is built on that principle, and it is judged by results that can be measured. The financial crisis of 2008 and 2009 hit the printing industry hard, and press manufacturers felt the same pressure. For any printing business working to recover over the medium and long term, strengthening KPM work is a practical step. The gain does not appear overnight. It arrives from doing KPM consistently and turning it into production knowledge instead of treating it as an occasional repair job.

Consider a simple comparison. A hotel with a flickering fluorescent tube that nobody bothers to check slowly loses the confidence of its guests. A printing press is an expensive machine with no ability to heal itself, so every small irregularity deserves attention.

Precision Measured in Microns

On a sheetfed offset press running at 175 lines per inch, a 1 percent dot measures under 0.015 mm across, far too small for the eye to detect. A sheetfed machine can print five sheets every second, each carrying millions of dots. A commercial web offset press can reach fifteen sheets per second. Holding that dot pattern as it transfers to the blanket and then to the paper depends on the cylinder journals and bearings, plus the shafts, bearings, gears, and side frames that carry the drive through the machine. All of them need excellent precision and stability. If they lose it, the two impressions no longer register on the same fine dots, and image defects appear as distorted or enlarged dots. Keeping components measured in thousandths of a millimeter at their original factory accuracy is the central task for press operators, managers, and maintenance staff alike.

Reading Press Condition as A, B, C, or D

It helps to sort machine condition into four grades. Grade A means the press is still within a good range. Grade B means some irregularity has been noticed and adjustment is due. Grade C means the problem has become visible and repair can no longer be postponed. Grade D means the press has clearly failed and cannot produce until it is fixed.

A press kept on the blue line, with regular oil changes, cleaning, and repair, stays within useful accuracy for five or six years. Around year nine it may reach the lower part of grade B, when worn components need replacement. It enters grade D territory only near year eleven. A press kept on the red line, with poor care, reaches the A to B boundary in three and a half years. Chains that are never cleaned or lubricated can fail in little more than a year. By four and a half years it sits in grade C, and by five and a half years it is unfit for use. The result is serious: lost print quality, lost capacity, damaged company assets, and damaged reputation. Press condition should be checked and diagnosed constantly, then adjusted, repaired, or overhauled so the machine keeps producing in good order.

Heinrich's Law on the Shop Floor

Apply Heinrich's law to the human body and a pattern appears. Each illness serious enough to require hospital care grows out of thousands of small bad habits. Behind it lie roughly 300 occasions of taking medicine at home and 29 visits to a clinic. A major press failure follows the same shape. Thousands of missed cleaning and lubrication tasks produce 300 smaller symptoms, such as oil drips, water marks, blocked air lines, abnormal heat, vibration, unusual noise, odour, loose parts, slack wiring, and clogged filters. Of those, 29 turn into real trouble: a press that will not run properly, a damaged bearing, or a failed vacuum and compressed air circuit. One finally becomes a burnt bearing, a dead air circuit, or a major electrical fault that stops production. People and machines alike accumulate small faults until they become serious enough to stop working. A press deserves the same care as the body, with close observation, cleaning, and maintenance to keep it running.

The Five S in Daily Work

The 5S movement from Japan has spread around the world like karaoke, and each step supports maintenance.

(1) SEIRI, or sorting, separates what is needed from what is not, arranges the needed items in order, and stores or removes the rest.
(2) SEITON, or setting in order, puts the necessary items in defined places within easy reach.
(3) SEISOU, or shining, covers cleaning the machine and tools inside and out and keeping the workplace and equipment clean. Cleaning doubles as an inspection, because the person wiping a surface notices irregularities. This is the most important of the five.
(4) SEIKETSU, or standardising, keeps body, mind, and surroundings free of dirt.
(5) SHITSUKE, or discipline, follows workplace rules and standard operating procedures, and encourages colleagues and staff to do the same.

Lubrication, Filters, and Cleaning

Daily work includes adding lubricating oil and grease, changing circulating oil, and cleaning oil filter elements, magnetic separators, water traps, and foreign matter. Water marks, adhesive residue, and dust are wiped away. Print cylinders, ink rollers, dampening rollers, grippers, and delivery chains are kept clean. Each task is a chance to look for irregularity, wear, heat, or anything unusual. Ink rollers, dampening rollers, and grippers that behave abnormally are adjusted and their parts replaced. Main bearings on a press are extremely precise, and they wear out when the wrong oil is used or when oil degrades. Gripper rollers that have flattened no longer apply enough pressure, and sheets stop transferring smoothly. Inspection and cleaning are how these faults are found.

Air, Oil, and Filtration Systems

Air, oil, and filters protect the efficiency of the supply pumps. A clogged filter mesh reduces air volume, which disturbs sheet feeding from the feeder, the side guides, the transfer suckers, and the delivery. A blocked oil filter starves the press of oil and causes wear that can lead to a major breakdown. Keeping filters clean, clear, and working matters a great deal. A clogged cooling fan filter on a motor causes overheating and burnout. For motor brushes, the original manufacturer recommends replacement at half wear, while Mr. Kawana suggests replacing at one third wear for greater safety and less erosion of the rotor. Belts on the air compressor age, and the air filter and oil and water separators need the same care. The compressor tank collects water on humid days, and draining it matters because trapped water affects cylinder movement and promotes rust. Static elimination units carry high voltage, so damaged or incomplete wiring can spark and start a fire.

Fire Risk and Electrical Housekeeping

Japan runs about three hundred commercial web presses, and on average one is lost each year when dust in the drying system or the folder ignites. Paper dust accumulates during printing, and a single spark can set the folder or oven alight, causing losses of tens of millions of yen or forcing a complete press replacement. Many filter and oil filter housings are made of clear plastic or glass so the contents can be checked, yet most are so coated in dust that the inside cannot be seen and should have been replaced long ago.

Grippers on sheetfed presses now close by cam. When one gripper jams, the cam force has no spring to absorb it, so a pressure of ten or so kilograms can multiply into several hundred, cracking the gripper arm and seat and damaging the cylinder surface, gripper shaft, closing rollers, and bearings. Electrical, electronic, and computer cooling fans also need clean intake filters, or parts overheat and burn out. Fan operation can be confirmed by holding a thread or a thin strip of paper at the outlet: if it moves, air is flowing, and no hand test is needed. Food should be kept out of the plant. Stored food attracts rats, which gnaw wiring and electronic circuits to wear down their teeth, and the starch based spray powder used in the press room makes an easy meal. In rural areas, rats can also draw snakes into the building, where they curl up under distribution boxes and machines.

Electrical distribution panels suffer most from dust, heat, burnout, water drips, oil drips, fly ash from ink mist, and traces of rodents, insects, and snakes. These lead to short circuits, power failure, and destroyed electronic parts, so cleaning them calls for care.

Seven Areas to Manage

Steady production and high quality, along with a long service life for the press, depend on seven areas: environment, press, plate, dampening fluid, paper, ink, and blanket.

(1) Environment covers room temperature, humidity, and lighting, along with water supply, power supply, and safe movement through the press room. It also covers oil and solvent handling, plant hygiene, and staff safety, supported by clear standard operating procedures.
(2) The press itself is managed with the 5S routine of lubrication, cleaning, adjustment, replacement, and inspection, including observation of irregularities and corrective repair.
(3) Plate management begins with CTP laser output, plate sensitivity, and developer stability, then adjusts the tone curve for each press and paper to build reproducible data for different printing conditions, while watching for scratches and coating stability.
(4) Ink management fixes brand and hardness values, controls press room temperature and keeps the inking system at a steady temperature, and stirs ink before it reaches the duct so its thixotropy improves. Loading too much ink at once lets it sit and harden, so a suitable film thickness is used; an excessively thick film harms the water and ink balance. The inking system is protected from drafts, high heat, and UV light, which raise ink tack and cause it to set on the rollers.
(5) Rollers and blankets need suitable hardness and elasticity, maintained rubber surfaces, and correct pressure. Blankets receive packing matched to their hardness. Dampening rollers are kept free of ink and oil, and ink rollers are kept free of gum buildup that causes ink stripping. Dampening rollers use IPA resistant hydrophilic rubber, while ink rollers use oil loving rubber.
(6) Dampening fluid uses suitable fountain solution and IPA substitutes, added automatically under pH control, though conductivity control can be more precise than pH control with a buffered solution. Filter changes, replacement of poor fountain solution, recirculation, and temperature control all belong here.

Results Measured in the Field

Three printing companies in China and seventeen in Japan have joined the KPM preventive maintenance system. After they began KPM repair and maintenance activity, maintenance costs fell noticeably in the first year. More importantly, sudden breakdowns dropped to below 20 percent of the emergency repair calls the manufacturers had previously handled, and the predictability of smooth production rose. In the second and third years, maintenance spending fell sharply and stable, high level print quality could be secured over the long term. Across eleven check categories covering environment, materials, dampening fluid, ink supply, water supply, blanket cylinder, plate cylinder, impression cylinder, printed product data management, measuring instruments, and 5S management in the press room, participating plants lifted their scores from an early 51 up to 86. Checking item by item gives machinery, environment, settings, and materials proper attention and brings them to suitable, acceptable condition. KPM inspection, adjustment, and repair take time in advance, yet over the long run they raise productivity and yield, cut rejects sharply, reduce repair time and repair cost, and keep print quality steady, so the press delivers reliable production service for many more years.