ENCODER
Documentation
A0001229 Rev 1.3, Aug 2011

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IMPIKA assumes no responsibility for any errors that may appear in this document. If you have any suggestion for improvements or amendments or have found errors in this publication, please notify us. At the time of publication, this document is intended to be as comprehensive and accurate as possible. However, information contained hereafter can be subjected to modification without prior notice. IMPIKA reserves the rights to modify the features and ESifications of its products without prior notice. This document has been designed by IMPIKA for its customers but also for its internal use. The information contained hereafter is the property of IMPIKA and cannot, under any circumstances, be totally or partially reproduced in any form or by any means including photocopying, without express written permission of IMPIKA. When devices are used for applications with technical safety requirements, the relevant instructions must be followed. Failure to use IMPIKA software or approved software with our hardware products may result in injury, harm, or improper operating results. Failure to observe this information can result in injury or equipment damage. Copyright © 2010 IMPIKA. All rights reserved.

A0001229 – Encoder Documentation

Table of Contents
1 2 3 About this Guide..........................................................................................4 introduction..................................................................................................5 Principle........................................................................................................6

3.1 Reminder of Shaft Encoder signal..............................................................6 3.2 Specification of the shaft ............................................................................6 3.3 Signal generation .......................................................................................6 4 Architecture..................................................................................................8 5 Specification of mechanical and electrical interfaces ............................10 5.1 The encoder .............................................................................................10 5.2 The interpolator ........................................................................................12 5.2.1 Mechanical integration drawing..........................................................12 5.2.2 Interpolator connector pins.................................................................12 6 Encoder Pitch Size (To be adjusted in the software)..............................14 6.1 Calculation................................................................................................14 6.2 How to determine the take-off diameter?..................................................15

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1 About this Guide
This guide provides all the technical details about the integration of an iEngine 1000 into an industrial equipment. It describes how to integrate the iEngine 1000 into an industrial machine. You will find: • • • • The mechanical specifications The electrical specifications The list of synchronization signals The integration of the printhead

Using this guide implies a full knowledge of ink jet technology terminology. The user of this guide is considered as qualified in the industrial integration (electrical and mechanical) and client/server-type TCP communication fields. Should you have any comments about this guide, please send them to IMPIKA’s Technical Department.

This documents is the property of IMPIKA. It cannot be copied or reproduced without prior written consent.

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2 introduction
The Impika Print Engine requires synchronizing the movement of the object to be printed with the frequency of activation of the piezoelectric units (ink jetting). To do so, the Print Engine is fitted with an encoder input (Shaft Encoder ES: subpixel encoder) that will be connected to a system which copies the displacement of the object. Whatever the resolution, this system will produce a pulse every micrometer. Impika proposes a solution consisting of a rotary encoder and of an interpolator to be directly connected to the ES input. This system can be assembled on a rotating axis or on a coding wheel rotating on a band or a belt. Composition of the encoding system: The system consists of the following parts: A rotary encoder with a 1-m long built-in cable. Reference: 01

An interpolator box Reference: 02 Delivered with a cable-connector set designed to connect the interpolator box output to the PRINT ENGINE controller box. Length: 2m. Reference: 03

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3 Principle
3.1 Reminder of Shaft Encoder signal
The signal to be generated at the Print Engine input (ES+, ES-) has the following characteristics: Differential (RS422) Rectangular Possible period range included between 0.5 and 1.5 µm Admissible jitter 5% (admissible period variation)

The encoder will send a signal every micrometer (possible value from 0.5 µm to 1.5 µm) This value is called "encoder resolution" and will be adjusted after analysing printed test patterns.

3.2 Specification of the shaft
In order to generate this signal, the encoder will be assembled on the axis of a shaft (wheel, driving roller, backing roll, etc.) the diameter of which is included between 60 and 120mm. The linear speed at shaft perimeter will be perfectly identical to the speed of the item to be printed (no shift, no play, shaft perfectly centred…). The encoder generates a sinusoidal signal of 5,000 pulses by shaft rotation. The interpolator output signal is multiplied by 50.

3.3 Signal generation
The encoder is connected to the interpolator that generates a square signal compatible with the Print Engine ES input.

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This documents is the property of IMPIKA. It cannot be copied or reproduced without prior written consent.

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4 Architecture
The integration of the encoder function can be done according to 2 ways : 1. directly on a rotating shaft driving the printing support.

Interpolator (x50)

Displacement encoding signal (accuracy inbetween 0.5 and 1.5 µm)

Impika Printing System (IPS)

Drop jetting signal (printing frequency)

DOD Print head
Printing support

Encoder take off shaft Encoder

2. or via a wheel, either on the support (e.g.: "web" application) or on the driving unit (cylinder, belt, etc.).

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Interpolator (x50)

Displacement encoding signal (accuracy inbetween 0.5 and 1.5 µm)

Impika Printing System (IPS)

Drop jetting signal (printing frequency) Recopier System Encoder Printing Support

DOD Print head

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5 Specification of mechanical and electrical interfaces
5.1 The encoder

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NOTA:

All the axes have to be guided in order to avoid any lateral movements. The tangent of the shaft has to perfectly match the displacement axis of the item to be printed.

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5.2 The interpolator
5.2.1 Mechanical integration drawing (Units in mm/inch)

5.2.2 Interpolator connector pins

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5.2.3 Interpolator default settings

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6 Encoder Pitch Size (To be adjusted in the software)
6.1 Calculation
The controller have to be set with the signal value (the latter will be included between 0.5 and 1.5 µm). This size depends on the diameter of the take-off shaft.

For instance, Take-off shaft diameter (mm): Perimeter (mm): Signal value after the encoder: Signal value after the interpolator:

65mm 204,203mm 204,203 / 5000 = 40,84 µm 40,84 / 50 = 0,8168 µm

Summary table of the possible values:

Shaft diameter (mm) Perimeter (mm) Number of encoder points Signal value after the encoder (µm) Printing resolution Maximum speed (m/s) Encoder output frequency (Khz) (1) Interpolation value Signal value after the interpolator (µm) Interpolator output frequency (Khz) 5000 37,70 600 dpi 1,25 33,16 50

60 5000 37,70 300 dpi 2,5 66,31 25 5000 50,27 600 dpi 1,25 24,87 50

80 5000 50,27 300 dpi 2,5 49,74 50 5000

100 5000 62,83 300 dpi 2,5 39,79 50 5000

120 5000 75,40 300 dpi 2,5 33,16 50

188,50 188,50 251,33 251,33 314,16 314,16 376,99 376,99

62,83 600 dpi 1,25 19,89 50

75,40 600 dpi 1,25 16,58 50

0,7540 1,5080 1,0053 1,0053 1,2566 1,2566 1,5080 1,5080 1 658 1 658 1 243 2 487 995 1 989 829 1 658

Note (1) : The encoder output frequency (or interpolator input frequency) should be limited to 100 kHz max. The Interpolation value should be set accordingly.

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6.2 How to determine the take-off diameter?
If the encoder is assembled on a shaft driving a belt on which the item to be printed is placed, the take-off diameter equals the diameter of the shaft plus twice the thickness of the belt. The theoretical value has to be adjusted in the printing controller to consider the equipment features. The final control can be done through the dedicated printing test pattern control.

BELT

Item to be printed

ENCODER

SHAFT

TAKE-OFF DIAMETER = TAKE-OFFDIAMETER + 2 x BELT THICKNESS = 61,15 + 2 x 5,50 = 72,15 mm

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61,15mm

5,50mm

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