Leather edge coating application system (edge inking machine)

01

Set how strips are fed, trimmed and coloured

European patent EP 1 075 552 B1 (Continuous automatic installation for processing and colouring the edges and tip of belts or other strips of leather or synthetic material) explains that in automatic installations the strip is laid flat and carried forward by rollers pressing on both faces, which can spoil the visible front end, may not give enough pull for proper cutting, and makes colouring of irregularly cut edges unsatisfactory; changing rollers and guides for different strips is also slow. The installation it describes pulls and guides strips by their edges with replaceable pairs of motor-driven rollers having a V-shaped groove, adjustable in spacing for the strip width, with knurled grooves at the front heads and smooth grooves at the rear. [1]

Between the front and rear roller heads, pairs of disc cutters and brushes treat the side edges. Each colouring head has a tapered roller whose lower end dips in a small vat of colour and transfers it to a grooved colouring roller in contact with the strip edge; an elastic ring keeps the two rollers in contact, spring tension adjusted by a screw keeps the colouring rollers against the advancing strip, and a brush on an elastic plate, set by a knob, regulates how much colour the rollers carry. The roller surfaces in contact with colour are coated with diamond powder for uniform transfer. Further versions colour the strip tip with small rollers or with a colouring unit that moves round the stopped tip guided by a cam. [1]

Galli's 2026 finishing and colouring catalogue gives figures for two edge inking machines. The semi-automatic RC 200 EVO takes strips 8–80 mm wide (an optional kit covers 3–8 mm), runs at up to 15 m/min, draws 0.14 kW and weighs 44 kg. The TEKNOCOLOR EVO used in its automatic Tecno System 100 line takes strips 15–60 mm wide and 800–1,800 mm long, also at up to 15 m/min, with 1.5 kW installed and a weight of 430 kg. [3]

Editorial note: send the supplier sample pieces with the real edge profile and the edge paint you use, and ask it to show the number of coats and the colour change procedure on those samples.

Give the supplier the piece types (belts, straps, small parts), length, width and thickness range, leather or synthetic material and tannage, edge profile, whether tips and curved outlines must be coloured, edge paint or dye type and viscosity, number of coats, colours and change frequency, required line speed, drying method and available length, upstream cutting and downstream burnishing, and power and extraction available.

02

Plan drying, collection and burnishing

In EP 1 075 552 the coloured strips are carried on continuous bands; coloured tips pass through a jet of warm air produced by fans and an electric resistance, and the drying means is preferably a tunnel oven with a continuous band placed in line between the processing and collecting machines. A collecting machine with a horizontal band and transverse thrust means, started by a microswitch when hit by the strip tip, moves each finished strip onto a chute where the strips pile up. [1]

US patent 5,941,101 (Belt edge burnishing machine) notes that depending on the leather grade and natural colour it may be necessary to paint or dye belt edges, that cutting leaves rough edges which are burnished, and that painting the edges before burnishing helps stiffen and flatten the fibres so they are knocked off more easily. In the burnishing machine it describes, the patent describes the edges being painted by hand before the loaded edge finishing boards entered the machine. [2]

The same catalogue lists the HORIZON belt dryer used after the RC 200 EVO in the Tecno System 10 line, with a 165 × 1,500 mm entrance opening, a maximum transport speed of 15 m/min and 3.5 kW installed power; an XL version takes 2,000 mm. Its data sheet gives a maximum temperature of 80 °C, while its feature list states 60 °C, so confirm the working limit for your edge paint. The GATE loader that places belts on the dryer has a 1,500 mm opening and also runs at up to 15 m/min. [3]

Editorial calculation: at 15 m/min, a line feeding 1,200 mm belts end to end with no gaps would pass about 12.5 belts per minute (15,000 ÷ 1,200). Real output is lower once gaps between pieces, extra coats and drying time are counted. [3]

Editorial note: if the coating line feeds a burnishing or second-coat step, agree with the supplier the dryness the edge must reach at the end of the dryer and the time available between steps.

03

Compare a camera-guided edge oiling machine for cut leather pieces

Two 2018 Chinese patent applications from Beijing Shen Chang Science and Technology Development Co., Ltd. describe a different layout from the strip line above: an edge oiling machine for cut leather pieces, in which a camera images the piece on a pallet of support cylinders, the control module calculates the edge point coordinates, and a motor-driven oiling head follows the edge. The oiling head is a cylindrical gear that turns in a horizontal plane while immersed in edge oil in an oil groove, with its side projecting through the groove's outlet onto the leather edge. [4]

The applications give these settings: channels on the gear's side surface spaced 1–3 mm apart, a 1–3 mm gap between the gear and the oil-groove outlet, and channel inclination angles between 0° and 180° set against the direction of rotation so that the feed is more even. The pallet support cylinders chosen to hold the piece stay at least a set distance from the edge, 3 mm in the example, so they neither block the head nor pick up oil; in the worked example a piece covered seven support cylinders. [4] [5]

The oil supply uses two reservoirs and two pumps controlled by a pressure sensor that weighs the first reservoir; the example low threshold is the signal produced when that reservoir holds 20% of its capacity, at which point the second pump refills it and the first pump stops drawing from the oil groove. [5]

Editorial note: patent applications describe an inventor's design, not tested performance; ask a supplier of camera-guided machines for the edge-tracking accuracy and the minimum piece size it can hold. [4]

04

From edge-gripping feed rollers to the strip collector

Every row follows the strip line of EP 1 075 552; the camera-guided oiling machine above uses a different head and is not listed here. [1]

05

Which strip widths and dryer temperatures can the line handle?

Width range and dryer temperature are the rows with Galli figures; check the dryer limit with care, since its data sheet and feature list disagree. [3]

06

Send the piece, paint and line data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Pieces: [type; length; width; thickness; material]
Edges: [profile; tips; curved outlines]
Paint: [edge paint or dye; viscosity; coats; colours]
Speed: [pieces or metres per hour]
Drying: [method; available length]
Upstream/downstream: [cutting; burnishing]
Changeover: [width; colour]
Site: [power; extraction; space]

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