GB2247376A

GB2247376A - Hand held portable printing device

Info

Publication number: GB2247376A
Application number: GB9113595A
Authority: GB
Inventors: Dennis Thomas Gilham; Raymond John Herbert
Original assignee: Alcatel Business Systemes SA; Alcatel Business Systems Ltd
Current assignee: ALE International SAS; Nokia UK Ltd
Priority date: 1990-06-29
Filing date: 1991-06-24
Publication date: 1992-02-26
Anticipated expiration: 2011-06-24
Also published as: FR2664074A1; GB2247376B; GB9113595D0; FR2664074B1; GB9014487D0

Description

HAND HELD PORTABLE PRINTING DEVICE This invention relates to franking devices and in particular to franking devices of sufficiently small size as to be portable and to be operated while hand held.

Franking machines utilised for franking mail are usually relatively large and heavy units which are located in a mail room or in a fixed location in an office and mail items are transported to the franking machine to be franked. Such machines are designed to handle relatively large numbers of mail items.

According to the present invention hand held portable device includes printing means operable to print an impression on a print receiving medium as the device is moved manually along the print receiving medium; scanning means to scan a pattern on a medium as the unit is moved along the medium; memory means to store print data for utilisation to control operation of the printing means; said device being operable in a printing mode to read out printing data from the memory to operate the printing means to print an impression and operable in a copying mode to write scanning data from the scanning means to the memory means for utilisation as print data to operate the printing means to print a copy of the pattern scanned by the scanning means.

The hand held device may be arranged for printing of franking impressions on mail items and preferably means are provided to inhibit the printing means from printing copies of franking impressions.

An embodiment of the present invention will now be described by way of example with reference to the drawings in which: Figure 1 is a sectional view of a hand held franking device with a printing device in an operative printing position, Figure 2 is a view, similar to that of Figure 1, with the printing device in an inoperative retracted position, Figure 3 is a block circuit diagram of the franking device, and Figure 4 illustrates a battery charger and the coupling thereof to the franking device.

Referring first to Figures 1 and 2, a hand held unit incorporating a franking device comprises a chassis and casing 10 on which a printing device 11 is mounted. The chassis 10 is provided with a pair of rollers 12, 13 for supporting the unit on a surface 14 of a mail item while the unit is moved across the surface. The printing device comprises a thermal print head consisting of a substrate 15 having a line of thermal print elements 16 disposed along an edge thereof such that the print elements are located between the rollers 12, 13. Mounted on the substrate 15 are drive circuits, not shown, for the thermal print elements 16. A thermal ink transfer ribbon 17 is fed from a supply reel 18 around a guide 19, past the print elements 16 and thence to a take up reel 20.A tachometer disc 21 is driven by a belt 22 passing around a pulley wheel 23 coupled to a shaft of the tachometer disc and a further pulley wheel 24. The further pulley wheel 24 is located adjacent the roller 12 and is urged toward that roller so that the belt 22 is frictionally engaged by the roller 12. Accordingly when the hand held unit is moved on the rollers 12, 13 across a mail item in the direction indicated by arrow 25 the tachometer disc is rotated. The take up reel 20 is driven from the shaft of the tachometer disc 21 through a slipping clutch and a reversal mechanism so that the drive to the take up reel tends to rotate the take up reel to tension the ribbon.

Instead of providing a reversal mechanism in the drive from the tachometer disc to the take up reel, a reversal mechanism may be provided between the roller 12 and the tachometer disc, such a mechanism may be constituted by an additional roller interposed between the roller 12 and the belt 22 on the roller 24. The printing device 11 is mounted on the chassis 10 to permit the printing device to move, relative to the chassis, in a direction indicated by arrow 26. A spring, not shown, acts between the chassis and printing device to urge the printing elements 16 into a position in which they project beyond a plane tangential to the exposed portions of the peripheries of the rollers 12, 13.Accordingly when the unit is placed on a mail item, initially the ribbon 17 is brought into contact with the surface of the mail item by the print elements 16 and when pressure is applied to the chassis 10, to counteract the force of the spring acting on the printing device, the chassis moves towards the surface of the mail item until the rollers are brought into contact with the mail item as shown in Figure 1. Thus the ribbon is pressed into engagement with the mail item surface by the spring pressure. A microswitch, mounted on the chassis, is operated by the movement of the print head against the spring force into a position in which the print elements and rollers 12, 13 lie adjacent the plane of the mail item surface. A buzzer is operated by operation of the microswitch to produce an audible sound to indicate to a user that the unit is correctly positioned for printing.

Instead of a microswitch, other position sensors may be used and for example may comprise a device which provides a varying output signal as the chassis is moved relative to the print head. The buzzer may be modulated in response to the pulses from the tachometer so that the sound from the buzzer provides an indication to the user of the speed at which the unit is being moved across a mail item. If the speed of movement of the unit is too high the printing device may mal-function and result in poor quality printing. Accordingly, the modulation may be made to become intermittent at a speed slightly less than a desired maximum speed to warn a user to move the unit at a lower speed. The roller 24, or the intermediate roller, are mounted such that driving engagement is maintained with the roller 12 for all positions of the print head relative to the chassis.

When the hand held unit is moved across the mail item surface, the thermal transfer ribbon tends to adhere to the surface and to be drawn off the supply reel 18. At the same time the roller 12 rotates and, by means of the belt 22, applies drive to the take up reel tending to wind up the ribbon which has passed the print head. The drive applied to the take up reel through the slipping clutch is arranged to be of sufficient torque and speed to peel the ribbon from the mail item surface as the unit is moved across the mail item.

Preferably the ribbon and the supply and take up reels are housed in a cassette to enable easy replacement of the ribbon when the ribbon has been fully used. The cassette includes the guide 19 and any other guides required to hold the ribbon in position such that, when loading a cassette into the chassis, the ribbon is located to pass round the print elements 16 as shown in Figure 1. The cassette is held releasably in the chassis for example by releasable catches.

The ribbon cassette together with guides for the ribbon and the tachometer disc may be mounted with the printing device in a unit indicated by broken line 27 and be movable with the printing device relative to the chassis 10. Alternatively the ribbon cassette and tachometer disc may be mounted directly on the chassis 10 and only the print head 15 is then mounted to move relative to the chassis. The tachometer disc 21 has a plurality of spaced slots adjacent the periphery thereof which are sensed by an opto-interrupter device 28.The drive to the tachometer disc and the spacing of the slots is arranged to provide a pulse from the sensing device for each 0.25mm of movement of the franking device and the output of the opto-interrupter is utilised to control the drive to the print head elements so that operation of the print head is synchronised to the movement of the unit across the mail item.

A keyboard 29 and display 37 are provided on the exterior of the chassis for example, as shown in Figure 1, on a side wall of the chassis. The keyboard is used to control operation of the unit and, when the unit is used for franking, for the input of the value of franking to be applied to a mail item. The display provides indications of the functions being performed by the device and to show the contents of registers of the device and the value input on the keyboard for a franking operation.

Electronic circuitry of the hand held unit comprises printed circuit boards carrying integrated circuit and other components. These printed circuit boards are housed in the chassis and casing 10. Conveniently, one printed circuit board 30 concerned with the display and keyboard may be mounted adjacent the keyboard and display device and a main controller printed circuit board 31 may be mounted on the other side of the printing device 11.

Control of the unit for effecting franking operations is by means of a secure module 32 fitted into the chassis.

There are no direct electrical connections to and from the secure module and all communication with the module is effected by means of inductive couplings. Electrical power to energise the module is transmitted by inductive coupling and the signal received by the module is rectified to provide the required electrical energisation.

The hand held unit also incorporates a scanner to enable images to be read for the purposes of copying the images or for identification of the images. For example the device may be utilised for verification of signatures. It will be appreciated that during use of the hand held unit for scanning an image the print head is not operated to cause printing and the print head is retracted from its operative printing position shown in Figure 1 to an inoperative position as shown in Figure 2. The scanner comprises a row of LEDs 33 extending parallel to the row of print elements of the print head. A cylindrical lens is provided to diffuse the light from the LEDs such that substantially even illumination is provided along a strip of a surface on which the hand held device is located. A row of light sensitive diodes 34 extends parallel to the row of print elements.Preferably a similar number of diodes is provided as the number of print elements so that the scanning resolution is substantially the same as the printing resolution. Light reflected from the strip of the surface illuminated by the LEDs is sensed by the light sensitive diodes and the outputs of the respective diodes represents the light reflective characteristics of a plurality of points along the illuminated strip. Thus if the surface bears an image such as a printed impression the output of the diodes at any instant will represent a strip of that image. The threshold of the diodes is set at a level to distinguish between regions of the surface bearing a part of the image and regions which have no part of the image and for example the diodes may provide a logic 1 output for dark regions and a logic 0 for light regions.The tachometer 21 provides pulses as the hand held unit is moved across the surface and these pulses are utilised to synchronise the scanning of a printed impression with the movement of the unit. Thus strips of information relating to the image are output in sequence as the unit is moved to cause the scanner to pass across an image. The state of each sensor at the occurrence of each pulse from the tachometer is read and may be stored to retain data representing the image to enable processing of the data to be effected. When verification of an image such as a signature is to be performed, firstly an authentic signature is read by the scanner and stored in a memory of the unit. Subsequent verification of a later signature is performed by reading the later signature and carrying out a comparison of the data obtained from the first and later scannings.

The electronic circuits of the hand held unit are powered by means of a rechargeable battery housed in a module 35 of the chassis 10. As shown in Figure 1, the module 35 is located at one end of the chassis 10 remote from the printing head 15. However if desired the module 35 may be accommodated such that it is located to one side of the chassis 10.

Referring now to Figure 3, the electronic circuits of the hand held unit include a processor 36 to control the functions of printing and scanning in dependence upon input from the keyboard of operation commands to select the function required. The processor 36 also outputs signals for operation of the display device 37. Software routines and fixed data required for operation of the processor 36 is stored in a non-volatile read only memory (PROM! 38. A random access memory (RAM) 39 is provided for storage of data to be printed and for data read by the scanner 40 as well as any other variable data required to be stored in operation of the unit.Signals output from the processor 36 to the display device 37 and printing device 11 and signals input to the processor from the keyboard 29, light sensitive diodes 34 and tachometer 21 are passed through an input/output interface 41. When printing, data to be printed by the printing device 11 is read from the memory 39 by the processor 36 and is output to and loaded serially into a print buffer of the printing device. The pulses of the tachometer 21 are utilised as strobe pulses to control read out of the print data from the print buffer to energise the thermal printing elements to effect printing of dots at selected positions in a row to build up a printed impression row by row as the hand held unit is moved across a surface.Similarly, when scanning, the outputs of the light sensitive diodes are strobed by the pulses from the tachometer and are then loaded serially into the memory 39.

When the hand held unit is to be utilised for printing franking impressions on mail items, the unit is operated under the control of a secure franking module 32. This module includes a processor 42 which is operable under software routines stored in non-volatile read only memory (PROM) 43. The read only memory also stores data for control of the printing device to print a required form of franking impression. A random access memory (RAM) 44 is provided for storing data utilised by the processor in carrying out an operation under the software routines.

Non-volatile memories 45, 46 are provided for storing data relating to accounting for usage of the unit in printing franking impressions. Such accounting data is used as the basis for payment for usage of the machine in franking mail items and hence the accounting data must be held in a secure manner and in a manner such that the integrity of the data is not destroyed by any mal-function of the unit.

For this reason registers for storing the value of credit available for franking, for storing the accumulated value of postage printed and for storing a count of items franked are provided in each of the memories 45, 46 and furthermore are duplicated within each of these memories.

As mentioned hereinbefore, no direct electrical connections are provided to the secure module 32.

Instead, communication between the circuits of the hand held unit and the secure module are effected by means of an inductive link. One part 47 of the inductive link is connected to a serial port of the processor 36 of the hand held unit and the other part 48 of the inductive link is disposed within the secure module 32 and is connected to a serial port of the processor 42. When the secure module is installed in the chassis 10, the two parts 47, 48 of the inductive link are located adjacent one another such that signals transmitted by one part are received by the other part of the link.

When a franking operation is to be performed, the required function is selected by operation of a selected key of the keyboard 29 together with input, by means of the keyboard, of a postage value. This causes the processor 36 to transmit to the processor 42, via the inductive link, the value of postage charge which has been input. In manner well known in the operation of franking machines, the processor checks that sufficient credit is available for the required postage charge. The processor 42 then sends to the processor 36 a signal which indicates that the requested franking has been authorised. This signal consists of, or includes, print data defining the fixed pattern of the franking impression stored in the memory 43 together the value of postage charge initially selected by operation of the keyboard.Upon receipt of the authorisation signal the processor 36 writes the franking impression print data into memory 39 from where it is read out to effect energisation of the print elements under control of strobe signals derived from the tachometer pulses to print the franking impression. As part of the franking operation, the processor 42 updates the registers in the memories 45, 46 to reflect the postage value used in the current franking.

The hand held unit may be operated to print out the values stored in the registers of the account memories 45, 46 of the secure module 32. This is accomplished by the processor 42 reading the registers and transmitting the values read to the processor 36. The processor 36 writes the values to the memory 39 to form print data to be read out to the printing device when the hand held unit is moved across a medium to receive these register values.

In another mode of operation the hand held unit may be utilised as a copier. In this mode of operation, the unit is moved across an image to be copied and the output of the light sensitive diodes is written into the memory 39.

After scanning of the image has been completed, the unit is operated in its printing mode in which the data stored in memory 39, from the scanning operation, is read out to operate the printing device as the unit is moved across a print receiving medium. If more than one copy is required, the data stored in memory 39 may be read out repeatedly as the unit is moved across the print receiving medium to operate the printing device to print out the required number of copies.

The battery of the module 35 is recharged by means of a circuit illustrated in Figure 4. The module 35 includes a rectifier circuit 49 connected to the battery 50 and driven from the secondary winding 51 of a transformer 52.

The transformer comprises a magnetic core constructed of two 'C' shaped core halves. One half 53 of the core is located in the module 35 with the ends of limbs of the core disposed to lie in or closely adjacent to the outer surface of the module and the other half 54 of the core is located in a charger module 55 with the ends of the limbs thereof disposed to lie in or closely adjacent to the outer surface of the module 55. Means are provided to locate the hand held franking unit on the charger module 55 such that the ends of the two halves 53, 54 of the core are aligned with one another to form a complete magnetic circuit. A primary winding is provided on the core half 54 which is energised from an A.C. mains power supply input 56.With the hand held unit located on the charger module 55, the primary and secondary windings are inductively coupled by the magnetic circuit provided by the aligned core halves and hence A.C. energisation of the primary winding results in a current being induced in the secondary winding. This A.C. current is rectified to charge the battery 50. If the battery module 35 is located at the end of the hand held unit remote from the printing head the hand held unit may be located in an inverted position on the charger module so as to align the two halves of the magnetic core. In this position the operative faces of the printing head and of the scanning components would be exposed and may be subject to damage.

However if the battery module 35 is located to one side of the hand held unit, as described hereinbefore, the transformer half core 53 may be located at the same end of the unit as the printing elements 16 adjacent the lower face of the unit. This enables the half core 53 of the transformer to be aligned with the half core 54 when the hand held unit is in its normal upright position in which the printing elements and the scanning components are protected by being adjacent the charger module instead of being exposed as in the inverted position of the unit.

It will be appreciated that no external electrical connections are required to the hand held unit and hence tampering with the unit by application of unauthorised electrical signals or voltages is inhibited. Similarly the lack of electrical connections to the secure module makes it difficult to tamper with the circuits of the module or the data stored therein. In order to provide additional security all messages sent to and from the secure module are coded. The secure module 32 may be arranged, by the provision of the necessary software in the memory 43, to be re-credited with additional credit.

This would be undertaken by return of the module to a postal authority. Alternatively re-crediting facilities may be omitted and the secure module would be issued initially with a purchased credit amount and be thrown away when this amount has been used in franking operations.

Since the unit is to be utilised for printing franking impressions it is necessary to ensure that the printing device is sufficiently functional as to be capable of printing an acceptable franking impression. This may be accomplished by carrying out a print element check each time the unit is powered to determine whether sufficient of the elements are within predetermined operational limits and that there is not an unacceptable concentration of any failed elements. The operation of the print head during a franking operation is checked by returning the print data from the print buffer after printing of each row of dots and comparing this returned data with the print data transmitted for that row to the buffer. If the comparison indicates an error, further printing is inhibited.In order to ensure that printing is effected when the print elements are energised, means are provided to detect that a thermal ribbon is present.

Additional checking of the printing of the franking impression may be implemented using the scanning facility.

The sensors 34 may be utilised to sequentially scan the printed franking impression during the printing operation to check that the quality of the impression is within a required tolerance. One or more of the sensors 34 may be utilised to provide an indication as the end of the thermal ribbon approaches the printing elements. The ribbon is wider than the width of the franking impression to be printed and the ink layer along a marginal edge of the ribbon, not used in printing the impression, is covered by a foil strip over a length of the ribbon adjacent the end thereof. When a franking impression is printed, marks are printed periodically alongside the impression utilising the marginal edge of the ribbon and these marks are sensed by the sensors 34 to provide a signal indicating that the ribbon is present. However when the foil strip covering the marginal edge of the ribbon is reached, the strip prevents printing of these marks and as a result the sensors 34 provide a signal to a user indicating that the end of the ribbon is approaching.

The strip is positioned so as to allow completion of printing of the current impression being printed but the signal from the sensors prevents further printing of franking impressions until a new ribbon has been loaded.

When the unit is being used for printing copies of patterns previously scanned by the sensors 34, the print head may be operated to print a background pattern along an edge of the print area, the background pattern being sensed by the sensors 34. When the foil strip is reached the background will not be printed and hence will not be sensed so that the sensors will provide an end of ribbon indication.

The provision of the copy function in the unit could facilitate illegal copying of franking impressions printed by the unit. Clearly the postal value of such copy impressions would not be accounted for by the secure module and hence if this were permitted to occur the postal authority could be defrauded of revenue.

Accordingly means would be provided to prevent such illegal copying. One method of preventing copying of franking impressions would be to compare the print data when the unit is in the copying mode of operation, with stored data representing the whole or part of a franking impression. If the print data and franking impression data are similar within predetermined limits, printing would be inhibited. Alternatively, scanning data may be compared with franking impression print data and printing inhibited if these are similar. Such checks may comprise a first check to determine if the basic outline or shape to be printed is similar to that of a franking impression.

If within predetermined limits further checks would then be carried out in a second phase.

Further security can be achieved by adding a suitable background pattern stored in memory to the output to the print head when the unit is being used for copying. This would provide a visual differentiation between an original and a copy of that original. Thus together with checking of the printed franking impression, satisfactory protection against illegal copying of a franking impression can be provided.

While the device has been described as having a thermal printing device, it will be understood that other printing devices such as ink jet printers may be utilised.

Claims

1. A hand held portable device including printing means operable to print an impression on a print receiving medium as the device is moved manually along the print receiving medium; scanning means to scan a pattern on a medium as the unit is moved along the medium; memory means to store print data for utilisation to control operation of the printing means; said device being operable in a printing mode to read out printing data from the memory to operate the printing means to print an impression and operable in a copying mode to write scanning data from the scanning means to the memory means for utilisation as print data to operate the printing means to print a copy of the pattern scanned by the scanning means.

2. A hand held unit as claimed in claim 1 wherein in the printing mode the scanning means is operative to scan the printed impression to provide scanning data signals; and in which the unit includes means responsive to the scanning data signals to check that the printed impression is within predetermined requirements.

3. A hand held unit as claimed in claim 1 or 2 including means to check operation of the printing means.

4. A hand held unit as claimed in claim 1, 2 or 3 wherein the printing means includes a thermal print head having a a plurality of print elements arranged in a line transverse to movement of the unit along a print receiving medium and a print buffer memory to store print data signals for operating the print elements to selectively print dots in a line during a print cycle, said printing means being operated in a plurality of print cycles as the unit is moved along a print receiving medium to build up a pattern line by line on the print receiving medium.

5. A hand held unit as claimed in claim 4 including comparison means to receive print data signals sent to the print buffer in a print cycle and to receive the print data signals from the print buffer after operation of the print elements in that print cycle; said comparison means being operative to generate a print error signal if the comparison is outside a predetermined limit.

6. A hand held unit as claimed in any preceding claim and powered by a rechargeable battery.

7. A hand held unit as claimed in claim 6 including charging circuit comprising a secondary winding electromagnetically coupled to a first core element and a rectifier connecting the secondary winding to the battery wherein the first core element has first and second ends located adjacent an outer face of the unit for magnetic coupling with respective ends of a second core element in an external charging module; said second core element having a primary winding electro-magnetically coupled thereto; said primary and secondary windings forming electromagnetically coupled windings of a transformer when the first and second core elements are magnetically coupled to transmit electrical power from the primary winding to the charging circuit.

8. A hand held unit as claimed in claim 10 wherein the hand held unit and the external charging module include co-operating locating means for locating the unit on the module in a position such that the first and second core elements are magnetically coupled.

9. A hand held unit as claimed in claim 8 wherein the printing means and scanning means are protected by the charging module when the unit is located on the module by the locating means.

10. A hand held unit as claimed in any preceding claim wherein the hand held unit is self contained and has no electrical connections from the exterior of the unit to electrical circuits in the unit.

11. A hand held unit as claimed in any preceding claim including means responsive to speed of movement of the unit along a medium to provide an indication of the speed to the user.

12. A hand held unit as claimed in claim 11 wherein the means responsive to speed provides a speed indication comprising a sound signal having a frequency varying with variation in the speed of movement.

13. A hand held unit as claimed in claim 11 or 12 wherein the speed responsive means is operative to provide an excess speed indication signal when the speed exceeds a predetermined limit.

14. A hand held unit as claimed in claim 11, 12 or 13 including strobe means responsive to the speed responsive means to strobe print data to operate the printing means and to strobe writing of scanning data to the memory means.

15. A hand held unit as claimed in claim 4 or in any of claims 5 to 14 when dependent upon claim 4 wherein the unit is provided with support means for movement along a medium and wherein the support means is manually movable against spring pressure relative to the printing means from an inoperative position spaced away from the medium to an operative position in engagement with the medium.

16. A hand held unit as claimed in claim 15 including means responsive to the printing means being moved into the operative position to provide a signal to a user.

17. A hand held unit as claimed in any preceding claim and additionally operable in a franking impression printing mode wherein said memory means stores franking impression data and the printing means is operable under control of franking impression data read from the store to print a franking impression of required postage value.

18. A hand held unit as claimed in claim 17 including means to input postage value data to control the printing means to print a franking impression of a postage value corresponding to the input postage value data.

19. A hand held unit as claimed in claim 17 or 18 including means operative in the copying mode of operation to prevent printing of a franking impression by the printing device.

20. A hand held unit as claimed in claim 19 including means to compare scanning data signals with stored franking impression signals, said means being operative to inhibit operation of the printing means when the scanning data signals are within a predetermined limit of said stored franking impression signals.

21. A hand held unit as claimed in claim 18, 19 or 20 including background pattern signal generating means operative in the copy mode of operation to apply background pattern signals to the printing means so that an impression printed by the printing means in the copy mode of operation incorporates the background pattern.

22. A hand held unit as claimed in claim 18, 19, 20 or 21 including accounting means to carry out accounting functions in respect of postage value used in the franking mode of operation.

23. A hand held unit as claimed in claim 22 including control means for controlling operation of the hand held unit and wherein the accounting means is housed within a closed secure module and is coupled for data transfer between the accounting means and the control means by an inductive link.

24. A hand held unit as claimed in claim 23 wherein the secure means includes a credit memory for storing a value of credit available for use in the franking mode of operation.

25. A hand held unit as claimed in claim 24 in which the credit memory is non-rechargeable.

26. A hand held unit as claimed in any preceding claim wherein in a first scanning operation first scanning data from the scanning means is written to the memory means and in a second scanning operation second scanning data from the scanning means is compared with the stored first scanning data.

27. A hand held unit constructed and arranged to operate substantially as described with reference to Figures 1, 2 and 3 of the drawings.

28. A hand held unit constructed and arranged to operate substantially as described with reference to Figures 1, 2 3 and 4 of the drawings.