Abstract: A franking machine is provided with receiver means to receive positional signals from a global positioning system. The franking machine may be operated to print positional data as part of a franking impression printed on mail items whereby the postal authority is enabled by inspection of mail items to determine that the franking machine is being used at its authorised location. The franking machine may be arranged to be inhibited from operation if not located at its authorised location. The positional signals may be utilised to correct variation in output of a weighscale due to gravitational variation.

Abstract: A franking machine is provided with a memory to store slogan print data and scanning means whereby a medium bearing a slogan desired to be printed is fed by mail item feed means of the franking machine past the scanning means to generate slogan print data to be written to the slogan memory. During subsequent franking operations, the slogan print data is read from memory to control a franking impression printer to print the slogan alongside the franking impression. A plurality of memories may be provided for storing a plurality of slogans and a selected slogan may be read from a selected one of the memories.

Abstract: A method and apparatus for transmitting print data signals serially to a printing device is disclosed. Print data for printing dots selectively line by line is stored as a plurality of bytes in which each byte represents the number of contiguous binary bits to be output to the printing device having the same binary value. The bytes are output to a comparator which receives the output of a counter driven by clock signals. The counter is started when a byte is output and the clock signals clock a data line held at a level representing the value of the bits. When the count equals the byte, the comparator toggles the data line so that it is at a level representing the next binary bits to be output. The apparatus is disclosed for use in a franking machine.

Abstract: A franking machine is disclosed in which the accounting memories are implemented by memory devices in which each storage location comprises a volatile and a non-volatile cell. During normal operation data is written to the volatile cells of the storage locations and in the event of a power down the data is transferred from the volatile to non-volatile cells. The volatile cells preferably are semi-conductor and the non-volatile cells are ferroelectric capacitative devices which retain their polarization without supply of power. The memory devices may provide storage for accounting data and other data processed by a micro-controller of the franking machine. In addition the memory device may be utilized to store other data which is not to be processed by the micro-controller.

Abstract: A method of improving the quality of printed impression obtained from thermal transfer printing on a print receiving medium having a poor print receiving surface is disclosed. A thermal transfer ribbon is fed with the print receiving medium and during feeding thereof thermal printing elements are energized selectively to print a required impression. The selected elements are energized repeatedly in a sequence of printing cycles to cause re-heating of the transfer ribbon to ensure that ink required to be transferred but not received successfully by the medium in one cycle is successfully received in a subsequent cycle.

Abstract: Means to control feeding of a multi-strike ink ribbon housed in a reversible cassette is disclosed. The cassette carries a magnetizable element and when the cassette is inserted in printing apparatus the element is located in operative alignment with a magnetic sensing device and with an electromagnet. Upon insertion of the cassette, the polarity of magnetization is sensed and provided the polarity is correct printing is enabled. If the polarity is incorrect printing is disabled. When the end of the ink ribbon is sensed, the electromagnet is energized to reverse the polarity of magnetization of the element so that when the cassette is removed and reinserted with reversed orientation, the correct polarity of magnetization is sensed and printing is enabled. A counter may be provided to limit the number of permitted reversals of the cassette.

Abstract: A franking machine in which the franking impression is printed by means of an ink jet print head. In order to determine whether all the ink jet nozzles are functional all of the nozzles are operated in selected ones of a series of print cycles to print a bar code. Reading means is provided to read a part of the bar code printed by a group of the nozzles and the information read is compared with information intended to be represented by the bar code. For successive printings of the bar code, the reading means is shifted transversely so that over a series of bar codes all the nozzles are checked.

Abstract: A method of forming a franking impression on a mail item and apparatus for forming the franking impression is disclosed. Material which is switchable from one stable state to another stable state by exposure to light of predetermined wavelength is deposited on the mail item while in one state and a selected region of the deposited material is exposed to light of the predetermined wavelength to effect switching of the selected region to the other state and thereby to represent franking or other secure information.

Abstract: A franking machine is disclosed in which a digital printing device such as a thermal printer or ink jet printer is connected to accounting circuits of the franking machine so as to be controlled thereby to print franking impressions. In order to prevent unauthorised control of the printing device by application of external print signals, print data signals output by the accounting circuit are encrypted by logically combining the signals with pseudo random strings of binary bits. At the printing device the encrypted print data signals are decrypted by logically combining the encrypted print data signals with a corresponding pseudo random string of binary bits to provide print signals to control the printing device. Connections between the decryption circuit and the print head are protected from unauthorised access.

Abstract: A franking machine for accounting for postage value used in franking items to be carried by postal authority or other carrier is constructed of electronic circuits specifically constructed to carry out specific functions and implemented by ASIC technology. Circuits for carrying out accounting functions, controlling a printing device to print franking impressions containing fixed pattern information and variable postage information are described.

Abstract: A ribbon feed for a thermal ink transfer ribbon (14) is disclosed in which the ribbon is drawn from a supply spool (15) and, together with an article (17) such a mail item on which printing is to be effected, is fed past a thermal print head (12). A tachometer (45) is coupled to the feed to generate pulses as the item is fed. A sensor (33, 34) generates pulses as the spool (15) rotates due to drawing of the ribbon therefrom. The number of sensor pulses occurring in periods determined by the tachometer pulses is compared with a predetermined value to provide to enable detection of occurrence of a fault in the ribbon feed from the spool.

Abstract: A franking machine is disclosed in which the franking impression is printed by means of an ink jet print head. Debris from mail items which is liable to be deposited on the nozzles of the print head is removed periodically by a cleaning device operated in gaps between feeding of successive mail items. In the event that a gap does not occur, the feeding means is controlled periodically to cause occurrence of a gap. The ink jet print head may utilize solid ink which is heated to melt it for ejection in drops from the nozzles.

Abstract: A franking machine is disclosed in which the accounting and control circuits of the meter are housed in a secure housing and a printing device for printing a franking impression is located exterior to the secure housing and is connected to the accounting and control circuits. Strings of print data sent to the printing device are returned in a succeeding print cycle to a check circuit in the housing to check integrity of the print data received by the printing device. If desired the print data strings may include a security code. In order to detect if the printing device has been disconnected from the meter, the meter includes a circuit to send a pulse train to the printing device via the connection for print data and to receive a pulse train from the printing device. The circuit compares the pulse trains and if the comparison is unsuccessful inhibits further franking operations.

Abstract: A thermal transfer printing device for a franking machine uses a multi-strike thermal transfer ribbon. Mail items are fed to the printing device and frictional engagement between the mail item and the ribbon during a printing operation draws ribbon from a supply spool. After completion of the printing operation, the mail item is separated from the ribbon and the ribbon is partially rewound onto the supply spool so that each portion of the ribbon is used progressively a number of times. An encoder disc on the supply spool shaft generates signals indicative of the length of ribbon drawn from and rewound onto the spool to control rewinding of the ribbon.

Abstract: A franking machine is disclosed which has a thermal printer for printing variable and non-variable information at a single print station. The non-variable information is printed by thermal print elements having a form corresponding to the information pattern and the variable information is printed by arrays of selectable print elements. The elements are preferably heated by passing electric current through the elements. Alternatively, the elements for non-variable information may be heated from a heated substrate.

Abstract: A method and apparatus is described for checking the operation of a thermal dot printer during a printing cycle. When a pattern is to be printed a count of the number of printing elements intended to be operated in the cycle is stored. A signal indicative of the total current drawn from a supply by the operated printing elements is compared with the stored count. If the comparison indicates that all or a sufficient number of elements have been operated to effect printing, operation of the printing elements in further printing cycles is permitted otherwise further printing is inhibited. In an alternative method the printing elements are operated to print data in machine readable form and the data is read to produce a signal which is compared with data intended to be printed. The printing elements may print the data in a form for visual inspection and in machine readable form. The printer may form part of a franking machine in which the printed data is a franking of a mail item.