GB2297293A - Controlling thermal printing parameters in postage meters in response to coded ink-ribbon cassettes - Google Patents
Controlling thermal printing parameters in postage meters in response to coded ink-ribbon cassettes Download PDFInfo
- Publication number
- GB2297293A GB2297293A GB9501733A GB9501733A GB2297293A GB 2297293 A GB2297293 A GB 2297293A GB 9501733 A GB9501733 A GB 9501733A GB 9501733 A GB9501733 A GB 9501733A GB 2297293 A GB2297293 A GB 2297293A
- Authority
- GB
- United Kingdom
- Prior art keywords
- printing apparatus
- ribbon
- printing
- cassette housing
- thermal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J35/00—Other apparatus or arrangements associated with, or incorporated in, ink-ribbon mechanisms
- B41J35/36—Alarms, indicators, or feed disabling devices responsive to ink ribbon breakage or exhaustion
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- Electronic Switches (AREA)
- Impression-Transfer Materials And Handling Thereof (AREA)
Description
THERMAL PRINTING APPARATUS
This invention relates to thermal printing apparatus and in particular to thermal printing apparatus in which printing elements are heated selectively to effect transfer of ink from a thermal transfer ink ribbon carrying a layer of ink.
Known thermal printing apparatus includes a thermal printing head having a plurality of thermal printing elements disposed in a line. A print receiving surface is pressed toward the line of printing elements with a thermal transfer ink ribbon interposed between the print receiving surface and the printing elements. The thermal ink transfer ribbon carries a layer of ribbon on one surface thereof and the ribbon is disposed such that the layer of ink is in engagement with the print receiving surface. During relative movement between the print receiving medium and the thermal printing elements the printing elements are energised selectively in a series of printing cycles so as to heat the elements selected in each cycle and thereby apply heat to areas of the ink layer adjacent to the heated printing elements.The applied heat is controlled such that the heated areas of the ink layer are caused to adhere to the print receiving surface. Subsequently, the thermal ink transfer ribbon is peeled from the print receiving surface to leave only the heated areas of the ink layer adhered to the print receiving surface.
The energisation of selected thermal printing elements in a series of printing cycles results in printing of dots at required positions along a line in each printing cycle and the line in which dots are printed in one printing cycle is displaced from the line in which dots are printed in a preceding printing cycle. Accordingly a required printed pattern is built up in a line by line manner in the printing cycles of the series.
In order to achieve a high quality print impression on the print receiving surface it is necessary that the power input to the thermal printing elements of the print head be controlled within predetermined limits to an optimum power level. If the power input is too low the areas of the ink layer are softened insufficiently to adhere to the print receiving surface. On the other hand if the power input is too high the areas of the ink layer may melt and the heat will be applied to relatively larger areas of the ink layer with the result that smudging of the printed impression is likely to occur and the printing impression will lack clarity.
The optimum power input level to the thermal printing elements is dependent upon the construction of the printing head and upon the characteristics of the thermal transfer ink ribbon. The characteristics of the thermal transfer ink ribbon may differ for example according to the manufacturer of the ribbon, whether the ink layer is wax or resin based, thickness of the ink layer and of the substrate or backing layer of the ribbon and colour of the ink layer. The printing head is mounted permanently in the printing apparatus and hence the energisation of the elements thereof can be set to an optimum level for that particular print head, the ink layer of the thermal transfer ink ribbon has a limited life and becomes used up. Hence the thermal ink transfer ribbon needs periodically to be replaced.A user of the printing apparatus may wish to use different ribbons, for example ribbons of different colour or ribbons supplied by different manufacturers. It is inconvenient to a user if there is a need to manually adjust the energisation of the thermal printing elements to an optimum power level determined by examination of the printed impression obtained.
According to the invention printing apparatus includes a thermal print head having selectively energisable thermal printing elements; a cassette housing containing a thermal transfer ink ribbon; means to bring the thermal transfer ink ribbon into heat transfer engagement with said printing elements and to bring a print receiving medium into engagement. with an ink layer of said ribbon; identification means on said cassette housing to identify a characteristic of said ribbon; sensing means responsive to sensing said identification means and control means operative in response to said sensing means to determine and control a power level input to said printing elements from a power source such as to achieve substantially optimum energisation of said printing elements for producing a high quality printed impression on the print receiving medium in conjunction with said ribbon having said characteristic.
The printing apparatus may be incorporated in and form a part of a franking machine for printing a value impression on an item indicating that a postage or other value charge has been made in respect of the item.
An embodiment of the invention will now be described by way of example with reference to the drawings in which:
Figure 1 illustrates diagrammatically printing apparatus of a postage franking machine, and
Figure 2 is a block circuit diagram of the postage franking machine including thermal printing apparatus in accordance with the invention.
Referring first to Figure 1, a franking machine includes a feed bed 10 extending over a base 11 of the machine. A thermal print head 12 is mounted over the feed bed in spaced relationship relative to the feed bed. The spacing of the thermal print head from the feed bed is sufficient to permit the passage of mail items 13, such as envelopes containing inserts, between the thermal print head 12 and the feed bed 10. Mail items are fed onto the feed bed by means of a pair of input feed rollers 14, 15 and thence to the thermal print head. An impression roller 16 is resiliently mounted in the base 11 of the machine such that the impression roller is opposed to a line of printing elements of the print head 12 disposed along a line extending transversely to the direction of feeding of mail items along the feed bed 10.Mounting (not shown) for the impression roller is pivotable so as to move the impression roller between an operative position in which the impression roller is resiliently urged toward the thermal printing elements of the thermal print head and an inoperative position in which the periphery of the impression roller is spaced from the printing elements and lies in the plane of, or below, the feed bed 10. A cassette housing 17 containing a thermal transfer ink ribbon 18 is mounted adjacent the print head 12. Unused thermal transfer ink ribbon 18 is fed along a feedpath from a supply spool 19 in the cassette housing 17 past a face of the thermal print head in contact with the thermal printing elements of the thermal print head. After passing the print head, the used thermal transfer ink ribbon 23 is wound onto a take-up spool 20 in the cassette housing 17. A rear face of the ribbon lies in contact with the thermal printing elements and a front face of the ribbon carries a transferable layer of ink. When a leading edge of the mail item 13 enters between the thermal print head and the feed bed, the impression roller is moved into the operative position such that the impression roller resiliently engages the mail item and urges the mail item into engagement with the ink layer and the rear face of the ribbon into engagement with the thermal printing elements. A drive motor (not shown) rotates the impression roller to feed the mail item 13 past the thermal printing elements of the print head 12.
Due to the engagement of the mail item with the ink layer, the ink ribbon is drawn from the supply spool past the printing elements by the feeding of the mail item. After passing the printing elements, the ink ribbon is wound onto the take up spool, the take-up spool being driven so as to maintain the used ribbon under slight tension and thereby peel the used ribbon away from the mail item. The feed path of the ink ribbon is defined by freely rotatable guide rollers 21, 22 mounted on the cassette housing and located respectively upstream and downstream of the print head.During passage of the mail item past the thermal printing elements, the thermal printing elements are energised selectively with pulses of electric current to cause heating of the selected elements and thereby heat areas of the ink layer of the ribbon adjacent the energised selected printing elements sufficiently to cause those areas of the ink layer to adhere to the surface of the mail item. The selective energisation of the thermal printing elements is effected in a plurality of successive printing cycles such that in each cycle areas of the ink layer in required locations along the line of the thermal printing elements are caused to adhere to the surface of the mail item. Energisation of printing elements in successive cycles as the mail item is moved past the line of elements builds up a required pattern of areas of ink adhered to the mail item in a line-by-line manner.As the used thermal transfer ink ribbon 27 is drawn round the guide roller 22 by the tension in the ribbon resulting from drive to the take-up spool 19, the used ribbon is peeled from the surface of the mail item leaving the areas heated by energisation of selected printing elements adhered to the mail item and forming a required printed impression.
After passing through the nip between the impression roller and the thermal printing head, the mail item passes through a nip between a pair of ejection rollers 23, 24 one of which rollers is driven to eject the mail item from the franking machine.
The energy level with which the thermal printing elements are energised is determined by the magnitude and/or duration of the pulses of electric current applied to the thermal printing elements. The energy level is controlled such that the heating of the thermal printing elements is sufficient to effect reliable transfer of ink from the ink layer of the ribbon to the mail item but is not so great as to result in a smeared printed impression.
It will be appreciated that in transfer of areas of the ink layer from the ribbon to the mail item during printing thereon, the ink layer of the ribbon becomes depleted. If the thermal transfer ink ribbon is a so-called single strike ribbon in which the areas of the ink layer are transferred from the ribbon only during a single pass of the ribbon past the print head the ribbon needs to be replaced each time all the ribbon has been drawn from the supply spool. Other ribbons, known as multi-strike ribbons, may be fed past the print head a number of times and each time only a part of the ink layer is transferred.
The cassette housing 17 is removably mounted on the franking machine and upon depletion of the ink layer, either of a single strike or a multistrike ribbon, the ribbon is replaced by removal of the cassette housing together with the ribbon and a cassette housing containing unused ribbon is mounted on the franking machine. The disposition of the guide rollers 21, 22 carried on the cassette housing ensure that as the cassette housing is mounted on the franking machine, the thermal transfer ink ribbon is guided to pass along the face of the print head without manual intervention by the user of the machine.
Similarly the take-up spool 19 is formed so as to engage with drive means of the franking machine as the cassette is mounted on the franking machine.
The power required to energise the thermal printing elements to achieve a high quality print impression is dependent upon characteristics of the thermal ink transfer ribbon. If the power input is too low the areas of the ink layer are softened insufficiently to adhere to the print receiving surface. On the other hand if the power input is too high the areas of the ink layer may melt and the heat will be applied to relatively larger areas of the ink layer with the result that smudging of the printed impression is likely to occur and the resolution of the printed impression will be impaired and the impression will lack clarity.The characteristics of the thermal transfer ink ribbon may differ for example according to the manufacturer of the ribbon, whether the ink layer is wax or resin based, thickness of the ink layer and of the substrate or backing layer of the ribbon and colour of the ink layer. A user of the printing apparatus may wish to use different ribbons, for example single strike or multistrike and ribbons supplied by different manufacturers.
It is inconvenient to a user if, each time a different ribbon is used, there is a need to manually adjust the energisation of the thermal printing elements to an optimum power level by examination of the printed impression obtained.
Accordingly the cassette housing 17 carries identification means 25 unique to and identifying the characteristics of the thermal transfer ink ribbon contained therein and the franking machine is provided with a sensor 26 operative to sense the means 25 on the cassette housing. The identification means 25 may be comprise reflective and non-reflective areas at predetermined positions of the cassette housing and the sensor 26 may then comprise a reflective opto-electric sensor. The reflective and nonreflective areas representing a code identifying the characteristics of the thermal transfer ink ribbon contained in the cassette housing. If desired other forms of identification marking may be utilised. For example magnetic elements may be carried by the cassette housing and the polarisation of magnetisation of the elements may represent a code identifying the ribbon characteristics.
Alternatively bar coding may be used or a semi-conductor device may store the identification code. The sensor 26 is of a type appropriate to read the code on the cassette housing.
Referring now to Figure 2, operation of the franking machine is effected by means of a micro-processor 30 operating under program routines stored in a read only memory (ROM) 31. As is well known in electronic franking machines, a keyboard 32 is provided for input of data by a user and a display 33 is provided to enable display of information to the user. A random access memory (RAM) 34 is provided for use as a working store for storage of temporary data during operation of the franking machine.
Non-volatile duplicated memories 35, 36 are provided for the storage of data which is required to be retained even when the franking machine is not powered. Accounting data relating to use of the franking machine for printing franking impressions representing postage charges for mail items and any other critical data to be retained is stored in the non-volatile memories 35, 36. A motor controller 37 is controlled by the microprocessor to control operation of motors (not shown) for driving the input drive rollers 14, 15, the impression roller 16, the mounting for the impression roller, ejection rollers 23, 24 and ink ribbon take-up spool 19. Sensors 38 are provided to sense and monitor feeding of the mail item and of the ink ribbon. The sensors provide signals to the microprocessor to enable the microprocessor to control operation of the machine. For example one or more sensors are provided to detect the presence of the mail item and the position of the mail item along the feed bed and a sensor is provided to indicate the speed of feeding of the mail item along the feed bed to enable the microprocessor to control speed of drive of a motor driving the impression roller such that the feed speed is maintained substantially constant. Other sensors 38 may be provided as required to monitor operation of other elements in the franking machine. As the mail item is fed past the thermal printing elements of the print head, the microprocessor outputs, on line 39, to the print head in each of a plurality of printing cycles signals selecting those ones of the printing elements which are to be energised in the respective cycle.A pulse of electrical power is supplied to the selected thermal printing elements from a power source 40 when a strobe signal, on line 41, is supplied by the microprocessor.
The energy level supplied to the thermal printing elements by a pulse of electrical power from the source 40 is controlled and varied by an energy level controller 42.
The energy level controller 42 is operated by the microprocessor in dependence upon signals received from the sensor 26, these signals being dependent upon the code read by the sensor 26 from the identification means 25 on the cassette housing. Prior to energisation of the printing elements, the microprocessor 30 monitors the output of the sensor 26 to set the energy level controller 42 to provide optimum power to the printing elements of the print head. The energy level controller may be set prior to each printing operation or, if the cassette housing can be replaced only when the machine is powered down, upon powering up of the franking machine.
Alternatively, means not shown, may be provided to detect whenever a cassette housing is mounted onto the franking machine, and the microprocessor may be programmed to set the energy level controller at such times as the cassette housing is replaced as well as at times when the machine is powered up.
It is to be understood that Figure 1 of the drawings shows only those elements required to explain the operation of the invention and does not show other elements which would be present in a franking machine. The construction of electronic franking machines is well known in the art and hence it is believed to be unnecessary to provide a detailed explanation of the operation of the franking machine. Figure 2 shows logical connections between the microprocessor and other electronic elements and in practice these connections may be provided by one or more busses.
Claims (10)
1. Printing apparatus including a thermal print head having selectively energisable thermal printing elements; a cassette housing containing a thermal transfer ink ribbon; means to bring the thermal transfer ink ribbon into heat transfer engagement with said printing elements and to bring a print receiving medium into engagement with an ink layer of said ribbon; identification means on said cassette housing to identify a characteristic of said ribbon; sensing means responsive to sensing said identification means and control means operative in response to said sensing means to determine and control a power level input to said printing elements from a power source such as to achieve substantially optimum energisation of said printing elements for producing a high quality printed impression on the print receiving medium in conjunction with said ribbon having said characteristic.
2. Printing apparatus as claimed in claim 1 wherein the control means is operative prior to printing each printing impression to set the power level input to the determined power level input.
3. Printing apparatus as claimed in claim 1 wherein the control means is operative each time the printing apparatus is powered up to set the power level input to the determined power level input.
4. Printing apparatus as claimed in claim 1 wherein the cassette is removably mounted on the printing apparatus and including sensing means responsive to mounting said cassette housing onto the printing apparatus and wherein the control means is operative in response to said sensing means to set the power input level to the determined power input level each time said cassette housing is mounted onto the printing apparatus.
5. Printing apparatus as claimed in any preceding claim wherein the identification means includes at least one predetermined location of the cassette housing having a characteristic representing the characteristic of the thermal transfer ink ribbon.
6. Printing apparatus as claimed in claim 5 wherein the characteristic of the predetermined location of the cassette housing is optical reflectivity.
7. Printing apparatus as claimed in claim 5 wherein the characteristic of the predetermined location of the cassette housing is magnetic polarity.
8. Printing apparatus as claimed in claim 5 wherein the characteristic of the predetermined location of the cassette housing comprises a code stored in a semiconductor element.
9. Printing apparatus as claimed in any preceding claim and forming a part of postal franking apparatus, said printing apparatus being operated and controlled by postage metering means to print postal franking impressions on mail items.
10. Printing apparatus constructed and arranged to operate substantially as hereinbefore described with reference to the drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9501733A GB2297293A (en) | 1995-01-30 | 1995-01-30 | Controlling thermal printing parameters in postage meters in response to coded ink-ribbon cassettes |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9501733A GB2297293A (en) | 1995-01-30 | 1995-01-30 | Controlling thermal printing parameters in postage meters in response to coded ink-ribbon cassettes |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9501733D0 GB9501733D0 (en) | 1995-03-22 |
| GB2297293A true GB2297293A (en) | 1996-07-31 |
Family
ID=10768774
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9501733A Withdrawn GB2297293A (en) | 1995-01-30 | 1995-01-30 | Controlling thermal printing parameters in postage meters in response to coded ink-ribbon cassettes |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2297293A (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2148567A (en) * | 1980-10-31 | 1985-05-30 | Canon Kk | Ink ribbon cassette for printer |
| JPS60189479A (en) * | 1984-03-09 | 1985-09-26 | Fujitsu Ltd | Printer |
| GB2205071A (en) * | 1987-05-27 | 1988-11-30 | Triumph Adler Ag | Ribbon cassette and method for operating an electronically controlled typewriter or similar office machine in conjunction with such a ribbon cassette |
| JPH01195088A (en) * | 1988-01-30 | 1989-08-04 | Nec Home Electron Ltd | Thermal transfer printer |
| GB2219553A (en) * | 1988-06-10 | 1989-12-13 | Triumph Adler Ag | Sensing information from ink-ribbon cassettes. |
| EP0351515A1 (en) * | 1988-07-19 | 1990-01-24 | Datamax Corporation | Ribbon assembly |
| EP0550227A2 (en) * | 1991-12-30 | 1993-07-07 | Neopost Limited | Multi-strike ink ribbon feed control |
| GB2266275A (en) * | 1992-04-20 | 1993-10-27 | Sony Corp | Colour video printer and ink-sheet cartridge used therein. |
-
1995
- 1995-01-30 GB GB9501733A patent/GB2297293A/en not_active Withdrawn
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2148567A (en) * | 1980-10-31 | 1985-05-30 | Canon Kk | Ink ribbon cassette for printer |
| JPS60189479A (en) * | 1984-03-09 | 1985-09-26 | Fujitsu Ltd | Printer |
| GB2205071A (en) * | 1987-05-27 | 1988-11-30 | Triumph Adler Ag | Ribbon cassette and method for operating an electronically controlled typewriter or similar office machine in conjunction with such a ribbon cassette |
| JPH01195088A (en) * | 1988-01-30 | 1989-08-04 | Nec Home Electron Ltd | Thermal transfer printer |
| GB2219553A (en) * | 1988-06-10 | 1989-12-13 | Triumph Adler Ag | Sensing information from ink-ribbon cassettes. |
| EP0351515A1 (en) * | 1988-07-19 | 1990-01-24 | Datamax Corporation | Ribbon assembly |
| EP0550227A2 (en) * | 1991-12-30 | 1993-07-07 | Neopost Limited | Multi-strike ink ribbon feed control |
| GB2266275A (en) * | 1992-04-20 | 1993-10-27 | Sony Corp | Colour video printer and ink-sheet cartridge used therein. |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9501733D0 (en) | 1995-03-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |