Printing Cylinder for Flexo Label Printing Machines

Printing cylinders are made to order for the press and repeat. Share the following with RK for a quotation:

• RK press model (or the make, model and gear pitch of another flexo press)
• Repeat length required, or the teeth count if you already know it
• Number of cylinders needed (usually one per colour unit for each repeat)
• Printing width of the press
• Whether the cylinders are for a quick-change unit or a standard unit

For reference: FMS-2S and FMS-3S cylinders are stable aluminium, lightweight and highly accurate, with a gear pitch of 1/8 CP and a repeat range of 200 to 650 mm on those presses; the 320-IFP Super Smart uses a common 120 teeth printing cylinder.

A printing cylinder, also called a plate cylinder, is the cylinder that carries the flexo printing plate in each colour unit. The photopolymer plate is mounted on it with double-sided mounting tape. During printing, the anilox roller inks the plate, and the plate cylinder presses the inked image onto the web against the impression drum or roller.

Each repeat length needs its own cylinder, because the circumference of the cylinder is the distance the image repeats along the web. A label printer therefore keeps a set of cylinders in the repeat sizes of the jobs the plant runs, one for each colour unit in use, and changes them at job change. The cylinder is geared to the press drive through a gear cut to the press's gear pitch, so its teeth count and the repeat are fixed together.

Stable Aluminium Construction

RK's presses use stable aluminium printing cylinders. Aluminium is light, so one operator can lift and fit a cylinder at job change without strain, and it holds its shape in the press so the print stays accurate. This is the construction described for the FMS-2S and FMS-3S series and used across the range.

Made to the Press Gear Pitch and Teeth

Every cylinder is cut to the gear pitch of the press it will run in and to the teeth count that gives the required repeat. On the FMS series the gear pitch is 1/8 CP; other RK models have their own. RK builds the cylinder to the press, so it meshes correctly from the first run. Cylinders can be made with any number of teeth the customer specifies.

Accurate Repeat and Concentricity

The cylinder body is machined true to its axis, so the image does not move up and down the web as the cylinder turns. Registration between colours depends on every cylinder in the line being equally accurate.

Quick Change Design

RK full servo presses carry a quick-change printing cylinder and fast job change system. Cylinders made by RK suit that system, so changing a repeat size is a matter of minutes rather than a rebuild of the print unit.

Supplied in Sets to Your Requirement

RK presses are listed with printing cylinder sets supplied as per the customer's requirement – for example three sets on the Flexo Printing Machine With Full Servo, tower and paper cup machines and two sets on the wide web hybrid press. Additional repeats are added as an accessory order.

Fits Common Cylinder Models

Some RK models run a common printing cylinder across all colour units, such as the 320-IFP Super Smart five colour intermittent flexo with its common 120 teeth printing cylinder. RK supplies the right cylinder for that layout too.

Before the job, the operator mounts the flexo plate on the cylinder with mounting tape, lining the plate up to register marks on the cylinder face. The cylinder is then fitted in the print unit, where its gear meshes with the press drive. On a servo press, the drive adjusts the cylinder position electronically for register; on a mechanical press, it is set by the unit's adjustment screws.

When the press runs, the anilox roller lays a measured film of ink onto the raised areas of the plate, and the plate cylinder turns against the impression drum with the web between them. The image transfers once per revolution, so the printed repeat equals the cylinder's circumference. Because the cylinder is light and true, it is easy to handle and the image lands in the same place every turn, which is what gives clean colour-to-colour registration across all units.

• Self-adhesive label printing – the everyday use, on every colour unit of an RK flexo press.
• New repeat sizes – adding a cylinder set when a new label size comes into the plant.
• Replacement cylinders – replacing a damaged or worn cylinder with one made to the original press.
• Multi-colour job sets – complete sets of one repeat for six or eight colour presses.
• Paper cup, shrink film and water bottle label printing – RK's tower and full servo variants for these jobs use the same cylinder construction.

The printing cylinder does not decide the substrate; the press does. With the plate mounted, RK cylinders print whatever the press is built for – self-adhesive label stock, unsupported paper, BOPP, PE and PET film, shrink film, paper cup board and similar materials. Tell RK the press model and the jobs you run so the cylinder set is made to the repeats you actually need.

• Magnetic Cylindercarries flexible dies in the rotary die cutting station of the press.
• Flexible Diethin steel dies made to your label shape.
• Solid Dieengraved rotary dies for long runs of one shape.
• Rubber Rollpressure and nip rolls for printing and converting machines.
• Powder Brake and Clutchunwind and rewind tension control.

RK Label Printing Machinery Pvt. Ltd. has built flexo label printing and converting machinery in Ahmedabad, Gujarat since 1995, works from three manufacturing units and supplies customers in 23+ countries. The printing cylinder is made by the same company that designs the print unit it runs in, so gear pitch, teeth, width and quick-change fit are right by design. Ordering cylinders, dies, anilox rollers and other consumable accessories from the press builder keeps one supplier responsible for the whole print unit.

• Press model first: the gear pitch and cylinder mounting must match the press. Send the RK model name or, for another press, its gear pitch and cylinder drawing.
• Repeat length: choose the circumference that fits your label size plus gap with the least waste. RK can calculate the nearest teeth count from your label size.
• Quantity: one cylinder per colour unit that will print the job, so a six colour job in one repeat needs six cylinders.
• Quick change: if your press has the quick-change system, say so; the cylinder is made to suit it.
• Plan ahead: order the repeats for your regular jobs together so the press is not waiting for a cylinder when a repeat job comes in.

The price of a printing cylinder depends on the press model, the repeat length and printing width, the number of cylinders in the set and whether it is for a quick-change unit. Prices are quoted ex-works Ahmedabad with GST at 18% applicable. If RK sends an engineer for fitting or setting, the engineer's transport and stay are borne by the customer. Send RK your press model and label repeats for a quotation.