DE4020578A1 - METHOD AND DEVICE FOR PRINTING POSTCODE MARKINGS - Google Patents

Description

This invention relates to the printing of machine-readable markings on envelopes, for Use in automatic mail sorting machines and the like.

It's post office practice, machine readable To print markings on envelopes, which the go through postal system to a special Specify sorting or delivery code.

It is common practice for the envelope to be in the Sorting office passes through a station at which the Envelope is visually presented to an employee; the clerk reads that from the sender to the outside the postal code written and presses then the appropriate keys to find an appropriate one machine readable code, for example a number of  Strokes, typically with fluorescent ink to print the envelope. In the case of Window envelopes, the employee reads the postcode, how he on the one in the envelope Correspondence piece is written, and presses again the keys to print the strokes.

The lines can then be detected automatically; consequently the envelope needs if the dashes once printed on the envelope, not yet to be processed once by postal staff until he is finally delivered.

Fluorescent ink as opposed to ordinary ink is used by many national post offices for the Markings that are to be detected automatically, specified to ensure that only the Marks themselves from the automatic detectors to be read. In practice it is general excluded that unwanted fluorescent Markings appear randomly on the envelopes and can be detected. However, some specify national post offices for example black ink.

The task of manually reading the postal codes and the Entering suitable markings manually is tedious and requires a high level of concentration on the side of the coding employee. It also takes Processing relatively long, so that a large number of Employees are needed if the mail volume is large is what is essential to the post office's labor overhead  contributes. Devices for machine reading from Postcodes are common, at least where the Codes are printed or typewritten. The Devices can use ordinary alphanumeric characters react. However, the level of accuracy of such devices is only moderate, and it is still necessary, employees to set the many "rejections" too edit that the device cannot read.

With window envelopes, the problem is the correct one Detect and read characters through the window worse, and consequently the expected one falls Accuracy from the conventional device even further.

It is the bulk user with whom the invention deals predominantly employed, in which the user Example a million pieces sent every month, all are of the same nature. A typical example could be be a bank that sends credit card statements. In a number of areas of responsibility Savings in postage rates are provided if the Envelopes in which these extracts are sent with the machine-readable code, Representative of the special postcode to be printed can because this is a post processing step in Post office eliminated. Although the savings per post may be small, large users can be significant Achieve savings on postage.

Furthermore, the bulk user wishes, as in the example a bank, which has credit card statements as above  does not issue the envelope at the time print on which the statement is printed. Much more the bulk user prefers that the envelope not only for the special extract is because it is difficult is to try the envelopes of the letters allocate, especially if other supplements additionally to be included in the envelopes have to. Accordingly, it is preferred only the excerpts unique, and window envelopes too to ship. So it's not cheap with one suitable machine-readable code pre-printed Provide envelopes.

A number of patents have been related to of the invention contemplated which patents are listed below:

U.S. Patent No. 38 95 220
U.S. Patent No. 43 17 030
U.S. Patent No. 47 43 747
U.S. Patent No. 48 21 195
U.S. Patent No. 48 00 504
U.S. Patent No. 48 00 506
U.S. Patent No. 48 62 386
U.S. Patent No. 41 58 835
U.S. Patent No. 46 41 347
U.S. Patent No. 47 57 189
U.S. Patent No. 47 97 832
U.S. Patent No. 48 00 505
U.S. Patent No. 48 53 869

UK Patent No. 5 50 618
UK Patent No. 40 27 142
UK Patent No. 43 06 817

European Patent No. 00 76 972.

U.S. Patent No. 38 95 220 by Nelson et al. with the title "Selectively Encodable Envelope Insert And Related Apparatus "describes a magnetically readable Envelope insert, which with bars of magnetized ink is provided on separable Parts of the insert are arranged. The insert can be read while still in the envelope is. The insert has special applications for insertion in reply envelopes, with different parts of the insert are separated from each other in order or order display different payment methods. To do this will explain on the table below on column 3 of the Referenced patents.

U.S. Patent No. 41 58 835 by Miura et al. with the title "Arrangement For Detecting A Window Area Of A Window-Having Mail Item "describes a device for Detect the location of a window zone Envelope using photoelectric Detectors.

U.S. Patent No. 43 17 030 by Berghell with the title "Mailing Package For Facilitating Automatic Sorting Of Mail "refers to machine readable encoded Orders on the outside of an envelope to provide. The invention has a special use for use with reusable envelopes. If the envelope is sent, for example by a Utility company to a customer, the coded Arrangements by punching openings accordingly an address in a sheet, and placing a sheet  of contrasting color provided behind it, so that the contrasting color of the back sheet by the Openings are visible, and through a window into one envelope containing something, and from one Sorting machine can be read. If the Envelope returned to the utility the position of the contrasting colored sheet moved so that it is behind an arrangement of in the Envelope punched openings lies so that these Arrangement can be read and sent to sort the returning mail simplify.

U.S. Patent No. 46 41 347 by Clark et al. with the title "System For Printing Encrypted Messages With A Character Generator And Bar-Code Representation "refers to a franking machine to be used for printing on various information, including a zip code (zip code) or a bar code, on the outer one Envelope or the like. The information will entered manually by an operator. The main impulse of the disclosed invention appears in the prevention of Fraud and counterfeit stamps.

U.S. Patent No. 47 43 747 by Fougere and others with the Title "Postage And Mailing Information Applying System" discloses a system for encrypting information on an envelope or other shipping item. The patent discloses printing a bar code a label, directly on an envelope or on a Insert that is visible through a window.  

U.S. Patent No. 47 57 189 of Daboub refers to a device for coding reusable Envelopes and disclosed a system for manual Enter bar codes on the outside of an envelope for internal shipping systems.

U.S. Patents No. 48 21 195, No. 47 97 832, No. 48 00 504, No. 48 00 505, No. 48 00 506. No. 48 53 869 and No. 48 62 388 all refer to Mass mailing systems, in which the information, which printed on the outside of the envelope, one Database is extracted.

In British patent application No. 21 93 160, applicant Thorn EMI plc, entitled "Printer" is a unit discloses in which facilities for determining whether a Address signal includes a postal code are provided. If a postcode is detected, an extractor directs the relevant information from a data storage, whereby the resulting signal with the address signal in one Is combined before adding it into one Address writer is given. The postcode is on the Envelope or label in a phosphor dot shape given, which is easily machine readable. The rest the address is printed in a conventional form. Consequently a multi-mode printer is provided, which in the Is in alphanumeric and in machine-readable phosphor dot code to print. The Printer can be a modified conventional printer and an impact push mechanism (e.g. one Five-type printing wheel arrangement) with two printing bands  (one for each printing form) or a ribbon with two strips to have.

British Patent No. 14 86 596, issued to Hotchkiss Brandt Mecanisation, entitled "Coding Head For Postal Envelopes And a Coding Station Fitted Therewith "will be a device for printing a machine-readable postcodes disclosed on an envelope. The system is intended to be used in one operation to become where control signals which one to print Characterize code marking as a function of a an address read by an operator is generated, which enters the address details into a keyboard and a logic device these into the appropriate ones Control signals translated. The print head closes one Arrangement for holding an envelope must be coded to match with a printing tape. A Large number of print bars, which parallel print heads, which are fitted to a part of the ink ribbon, is provided with the number of bars equal to Number of print coding marks that are printed can be is. The coding head can be used by hand individual envelopes are supplied by an operator or can be automatically placed in the reading position from which the envelope manually to a coding position is transferred.

British Patent No. 5 50 618, issued to Remington Rand Inc., entitled "Improvements In Or Relating to Statistical Machines "reads a machine the information contained in a punch card and  then prints this information on the same card. The Machine reveals a complex mechanical arrangement to scan the perforations on a perforated Card, this information being held temporarily, the information is decoded and the decoded Information on the card in a different place is printed in the machine.

In U.S. Patent No. 40 27 142, by Paup et al., With the Title "Automated Processing Of Financial Documents" is a device for automatic processing of Bank checks revealed. The checks are with a line encoded by alphanumeric characters and then by Pass through a first station to generate one unique item control number and for each document a reading station for scanning each character in the encrypted line to a series of data signals generated for each document. At a Print station will be the control number and other data on the back of each document in code form printed, and the control number and other data will be to the view side of every document in from people printed legible form. The reading station closes one MICR reading station, an OCR reading station and one Bar code reading station. The reading station closes a bar code inkjet printer, one Bar code indicator and a double alphanumeric Inkjet printer. The MICR reading station is used to the bottom of each check in magnetic ink read encrypted alphanumeric data while the OCR reading station the same line of information  read. This information is put together to to produce a single output data stream. The Print the correct information on each check synchronized by means of a central computer.

In U.S. Patent No. 43 06 817, by Alas, entitled "Bar Code Printing Mechanism" will use disclosed two synchronized printheads that are longitudinally apart by half a bar from, for example, a US postcode to press. Operation of the foremost head is for one Delayed period of time sufficient that Target object to allow a distance that is approximate is equal to the distance between the heads to have.

A first aspect of the present invention recognizes Method of encrypting correspondence before to directing correspondence to a destination address through an automatic shipping goods sorting device facilitate. The process comprises the steps:

• a) Marking a letter with an easy machine readable first code corresponding to that of Human readable postal code of destination address;
• b) Put the letter in a window envelope so that the first code is within the window;
• c) machine reading the first code in the window; and  
• d) printing a machine-readable second code according to the first code and that of humans legible postcode of the destination address at the Digit and in the format as of a particular automatic goods sorting device used, so that the envelope is suitable for processing through the device.

This procedure allows a bulk mailer, like one Bank or credit card company, the monthly Send out excerpts for the post office to provide which is already a first Have gone through the processing step, that is, the Marking a machine-readable marking according to the postal code on the outside of the envelope in a way that automatic sorting of the Shipping goods allowed. Marking the letter with the First code conveniently takes place when the letter is marked with the destination address. Also needed the use of window envelopes not the Correspondence of a letter or other correspondence with a specific envelope, and simplified a lot the envelope filling operation, which allows this with a conventional device that is easily available is carried out.

According to a second aspect of the present invention a method of encrypting correspondence provided to direct the correspondence to a Destination address through an automatic To simplify shipping goods sorting device, which the Steps include:  

• a) Mark a package with a light machine readable first code corresponding to that of Human readable postal code of destination address;
• b) machine reading the first code; and
• c) printing a machine-readable second code according to the first code and that of humans legible postcode of the destination address at a Place and in a format as of a certain Shipping code sorter used.

This particular aspect of the invention is not necessarily the use of window envelopes is advantageous, for example, where a number from envelopes to various different To send destination addresses with the same enclosures is, or where a number of the same postcards too must be sent to different destinations.

Another aspect of the invention provides a device to print coded marks on an envelope in front. The device includes a reading station and one Printing station, and a means of transport of the envelope in between.

The reading station includes an optical sensor which is preferably arranged to avoid reflections of the marks on the correspondence to include and is effective in a series of electrical signals To generate agreement with it. The device  includes calculation means, a means of transmission of the electrical signals from the optical sensor to the Computer, a means of transferring resulting Signals to the printing station, and a means of arrangement the signals into a sequence of pulses at a distance from each other.

The print station closes at least one Signal-controlled printer, which during normal Operation of the device at a fixed pressure point the printing station remains.

In one aspect of the invention, this accepts Calculation means signals of an offset of the passing envelope from the printing station and the Reading station, and coordinates these transfers with the Signals from a read head, which makes the printer effective is to print a mark on the envelope while the envelope passes the printing station, and a series from such markings on the passing envelope an apart sequence in accordance with to print the spaced pulses.

Each station is preferably provided with a circulation counter or angular offset indicator, which is engaged with the passing Envelope, causing the linear offset of the passing envelope the angular offset of the counter corresponds.

One of the difficulties in reading printed  Markings through a window is that of the reading sensor tends to be the edges of the window as one of the Read markings. The first aspect of the invention it describes how it relates to its application Window envelopes, but should be noted that the said difficulty also occurs in the case can where the marks to be read on a Adhesive label are printed, in which the reading sensor Has a tendency to detect the edge of the label, as if it were one of the markers. The scope of the Invention should be considered accordingly. How will be described immediately, the first aspect allows the invention of the reading sensor, the markings clear and to read exactly with good tolerance and offset the Reading sensor still able to edge the window or ignoring the edge of the label.

In a preferred construction for use with Window envelopes have a reading head at the reading station provided a photodetector. The photodetector gropes the window of a passing envelope from time to time detects the presence of one on the correspondence piece printed in the envelope, and through the window visible bar.

The window of a window envelope is general Usually with a filling made of transparent material, such as such as cellophane, and the read head must Presence of the beams through the transparent material detect. A resilient glider is preferred provided for the purpose of filling on the Smooth correspondence piece.  

The thickness of the envelopes can vary in the range of less than 1 mm to about 5 mm. The read head will preferably on a parallelogram connection assembled, through their operation the passing envelope can deflect the read head upwards, and the read head still in the correct position relative to that Window remains. The task of scanning Marks through a transparent filling some requirements and it has been recognized that the Orientation of the read head to the window is critical. A preferred way in which the read head is arranged to take these aspects into account described below.

Yet another aspect of the invention provides one Printing station in front of where the beams (or other machine-readable markings) on the outside of the Envelope will be printed, with the pattern of the bars in Match the postal code as it is from the Read sensor was read is.

In the manual system referred to earlier the bars on the envelope were covered by solenoids activated hammers applied: the operator presses buttons in accordance with the code it reads and the Buttons activate the solenoids. Generally request Post offices that the fluorescent bars are about 6 mm high and about 1 mm wide, and the developer of the Device specifies a suitable solenoid.

A characteristic of conventional solenoids is that  they work comparatively slowly due to the Inertia of the (large) anchor. The present invention is for use with a device with a Throughput of two or three envelopes per second, at what speed a time interval between fluorescent bar of approximately 5 ms. For such speeds is printing through conventional solenoids unsuitable.

This aspect of the invention provides a means of printing from fluorescent bars to an envelope before to designate a postal code in which the means for Print the pair of fluorescent bars Dot matrix printheads which are arranged on the envelope by a fluorescent ink containing tape to print. In the invention they are Printheads stationary in the device and side Arranged in a line along the side Direction of travel of the envelope through the device. The two printheads are on the side with respect to the Direction of travel of the envelope offset, creating a Printhead the lower half of the bar and the other Printhead prints the top half of the bar.

A dot matrix print head of the configurations which are commonly available, only prints one bar approximately 3 mm high. That is the reason that two Printheads are needed to add a 6 mm high bar to press. Dot matrix printheads do not get wider than 3 mm made because dot matrix printheads unchanged be controlled by a computer, and it usually  even if higher printing is needed, it's not big Has consequences to programming the computer that Causing the printhead to run more than one pass Making paper.

The arrangement of the invention allows conventional Dot matrix printheads are used, and the Invention allows the benefit of their characteristic response, the simplicity of the Programming and well-developed reliability can be used.

In conventional dot matrix printers - at ordinary application in what dot matrix printer are found - only one head is provided, and this one a head is in motion by a transport mechanism driven, which the print head at right angles to Movement of the paper moves.

It would be under the circumstances of the present invention not practical to move the envelope sideways (i.e., the envelope at right angles to the line its passage through the device) while passing through the printing station is running. In the invention it is neither necessary, the envelopes still the print heads sideways move. Indeed, it would be almost impossible, either a single 3 mm head or the envelope on the side move fast enough to make a 6mm high bar to press. It has also been recognized that it is difficult would be to arrange that the envelope be the printing station happens twice, which is a possibility of one  Developer could be considered: it must be considered that there is a 6 mm high beam too would be possible to print the envelope twice by one to run only 3 mm printing unit. However this will dramatically reduce throughput and will in not considered this aspect of the invention.

Dot matrix printheads are computer controlled, and it is been recognized in the invention that there are none There are difficulties in programming the computer to operate both printheads in the correct order.

To further explain the invention is now under An example with reference to the accompanying drawings Embodiment of the device of the invention described in which drawings:

Figure 1a is an illustration of a method of encrypting envelopes according to a first aspect of the present invention;

Figure 1b is an enlarged plan view of an envelope which has been processed in accordance with the method of Figure 1a;

Fig. 2 is a side view of an apparatus assembled and arranged for operation in accordance with the invention;

Figure 3 is a block diagram showing the operational connections between the various components of the device of Figure 2;

Figure 4 is a close-up side view of a reading station of the device of Figure 2;

Figure 5 is a close-up side view of a printing station of the apparatus of Figure 2;

Figure 6 is a cross section along line 6-6 of Figure 4;

Figure 7 is a cross section along the line 7-7 of Figure 4;

Figure 8 is a cross section along line 8-8 of Figure 5;

Figure 9 is a broken away view of another form of printing station for use in another embodiment of the present invention;

Figure 10 is a top plan view of the printing station of Figure 9; and

Figure 11 is an end view of the printing station of Figure 9.

Figure 1 of the drawings shows a flow diagram illustrating the major process steps of the present invention, which is intended for use primarily by those involved in large volume shipping. The invention allows a shipper to mark envelopes or other correspondence with a machine-readable code suitable for reading by an automatic mail sorting device as used by a local, national or regional post office. This marking is normally carried out by the post office after the shipper has received the goods. Thus, the method and apparatus of the present invention allows the post office to eliminate a major processing step in its sorting process and this benefit can be passed on to the shipper in the form of a lower postage rate.

The method of a first aspect of the invention comprises four basic steps, as illustrated in Figure 1a as follows:

• a) Marking a letter with an easy machine readable first code corresponding to that of Human readable postcode of the destination address Letter;
• b) inserting the letter in a window envelope, see above that the first code is positioned in the window; and  
• c) machine reading the first code in the window; and
• d) printing a machine-readable second code according to the first code and human legible postcode of the destination address at the Body and in the format as it would by a particular automatic shipping goods sorting device is so that the envelope is suitable for the Processing by the device.

The process is first described relatively briefly, followed by a more detailed description of the Method and device of the invention.

The machine readable first code takes the form of a series 36 or bars 37 which form a bar code which is printed on the correspondence, in this example an extract which is printed under the destination name and the destination address at the same time, and with the same typical black ink used to print destination name and address.

The letter marked in this manner is then placed in a window envelope 28 along with any equipment using a conventional envelope inserting device such as the Bell & Howell MAILSTAR (Trademark). The letter is folded and placed in the envelope where the address and bar code are visible through window 29 .

The filled envelope is then in a Encryption device promoted. The Encryption device closes a reading station where the first code in the window is read.

The read code is then processed by the device, and when the envelope is "downstream" to a printing station from the reading station, the second code is printed on the envelope, the second code in terms of location, ink and format according to that of the special automatic shipping sorting device used by the local post office. In the illustrated example, the second code is a series 49 of bars 56 that form a bar code printed with fluorescent ink.

In further exemplary embodiments, the first code can be printed on a label or the like for Stick on the front of an envelope. This Methods of addressing and encrypting can be particularly suitable where the inclusions of the Envelopes are the same, and no need exists, the special inclusions with special Matching addresses.

The method and apparatus of the invention will be now described in more detail.

The drawings are diagrammatic, and some Construction details were taken from the drawings  left out for clarity of presentation enrich.

Fig. 2 shows the device as a whole. The device includes a fixed base frame 2 , which includes a base plate, supports, and a lower track frame 3 . An upper track frame 4 is one with the base frame 2 during operation of the device, but can be opened relative to it for service purposes.

A lower conveyor belt 5 is driven by a motor (not shown). An upper conveyor belt 7 is pressed by spring force at various points 8 against the lower conveyor belt 5 , the arrangement being such that the two belts are driven in unison. The conveyor arrangement can include belt tensioners 9 . The arrangement of the conveyor arrangement is such that an envelope is caught between the upper and lower belts and is thereby transported through the device.

The front ends of the conveyor belts 5 , 7 (the right end in Fig. 2) do not quite reach the end of the frame. Thus, the envelope is only gripped between the conveyor belts 5 , 7 after the envelope has already covered a distance into the device. The first part of the transport of the envelope after entering the device is handled by a pair of roller rolls, of which the lower roll 10 is driven by an electric motor (not shown).

The drive arrangement is that the conveyor belts 5 , 7 operate as if the envelope were being transported at a faster rate than the roller rolls 10 , 12 . In fact, however, there is no slippage and the effect is limited to the generation of tension in the envelope as it passes from the roller rolls to the conveyor belts. The reading station 16 of the device is positioned in the device so that the portion of the envelope that is read in the reading station is subject to a induced voltage.

The reading station 16 is described in more detail below. The device also includes a printing station 17 , which is also described in more detail below.

A reading station position sensor 18 is positioned in the lower track frame 3 at the reading station 16 , as shown schematically in Fig. 3 of the drawings in some detail in Fig. 4 of the drawing, which comprises a wheel 19 , an associated spring-loaded cam roller 20 , and a revolution counter 23 ( Fig. 7), such as a SUNX rotary shaft encoder. The arrangement is such that as soon as an envelope passes between the wheel 19 and the cam roller 20 , the wheel 19 begins to rotate, the rotational offset of the wheel 19 being a measure of the linear offset of the envelope when the envelope is conveyed through the reading station . Therefore, the angle output indicator of the counter 23 is a measure of the linear offset of the envelope with respect to a particular point in the reading station.

A photocell 24 ( Fig. 3) is inserted into the track frame 4 for the purpose of detecting the presence of an envelope. During normal operation of the device, when envelopes continuously pass through the device, the wheel 19 will not stop rotating between the envelopes, and in fact the wheel will hardly slow down due to its inertia between envelopes. Therefore, the mere fact that the wheel 19 rotates cannot be relied upon as the signal that there is an envelope in the station. Instead, the photocell 24 indicates the presence or absence of an envelope that passes through the reading station 16 . A computer 25 is provided in the device, the computer being programmed to only start receiving the output from the counter 23 after the photocell 24 has been activated.

It will be appreciated that the photocell should preferably be positioned in the station so that the envelope engages wheel 19 before the envelope triggers photocell 24 to ensure that the wheel is up and running before indications from the wheel into the computer.

A similar arrangement is provided with respect to the printing station 17 . A photo cell 26 senses whether an envelope is present at the printing station. Again, the computer 25 accepts output from a print station cycle counter 27 only when the photocell 26 indicates that an envelope has entered the print station.

The photocells are mounted on a guide 34 ( Fig. 6). The guide is laterally adjustable to accommodate different envelope widths. The guide and the photocells are not shown in FIGS. 4 and 5 for clarity, but their positions are indicated by the numbers 24 and 26 .

The envelope 28 ( Fig. 2) is of the type to which the invention relates, provided with a window 29 which is formed by cutting through the material of the envelope. A filling 30 made of cellophane or other suitable transparent material is glued into the cut-out zone.

The conventional arrangement with window envelopes is that a name and address written on a correspondence piece (in this example, a credit card statement) 35 placed in envelope 28 is visible through window 29 . In accordance with the method of the invention, as mentioned above, a series 36 of bars 37 is printed on the extract 35 so that the series 36 is also visible through the window 29 . The spacing and arrangement of the bars 37 is such that the series 36 indicates the appropriate post code and error checking verification, preferably in the form of a parity check property. The bars 37 are printed in ordinary black ink and are printed on the statement with and adjacent to the other personal details and a destination address.

It is described below how the invention enables a reading sensor to read the bars 37 through the fill 30 with the required level of accuracy and sensitivity. One difficulty that should be considered in the reading process is to make the sensor insensitive to the edges 38 , 39 of the window 29 - the problem is that the reading sensor could detect the edges 38 , 39 of the window as if the edges were bars 37 . In the same way, the reading sensor could detect the edges of the envelope 28 as if they were bars.

The reading sensor is generally designated by the number 40 and is explained in some detail in FIG. 4. The difficulty on the side of the reading sensor 40 in having to detect the difference between a bar 37 and an edge 38 , 39 can be avoided in the invention. The computer 25 can be programmed to ignore the information from the reading sensor 40 until the envelope has been moved a predetermined distance into the reading station. Thus, the photocell 24 is used to indicate the moment when the envelope 28 enters the reading station 16 . The output from the reading sensor 40 can then be ignored until after the counter 23 indicates that the leading corner 38 of the window 28 has passed a reading line 41 . The reading line 41 is the line in the reading station 16 at which the sensor 40 actually scans the series 36 of bars.

It cannot be avoided that the correspondent 35 must be given considerable freedom of movement within the envelope 28 to allow the use of conventional envelope filling machines. Likewise, the envelope is sometimes filled with accompanying correspondence, but sometimes the envelope will only contain the bare excerpt for itself, and the dimensions of the excerpt and the envelope must be acceptable in both cases. Therefore, it cannot be avoided that the first of the bars 37 in the series 36 can sometimes be as close as about 3 mm to the leading edge 38 , and on other occasions the first of the bars can be 20 mm behind the leading edge. In the same way, the position of the beams 37 on one occasion may be laterally offset by as much as 10 mm from the position of the beams on another occasion. In the same way, the series 36 can also lie at an angle relative to the direction of movement of the envelope.

On the other hand, it is not difficult to manufacture the envelope with reasonably close tolerances, whereby the distance 45 from the leading edge 46 of the envelope to the leading edge 38 of the window cannot be expected to vary more than about 1 mm. The result is that the photocell 24 , which is very reliably activated by the edge 46 of the envelope, can be used, with adequate accuracy, to indicate the moment at which the leading edge of the envelope passes the photocell, and therefore by simply adding preset ones to specify precisely known distances the moment at which the leading edge 38 of the window releases the reading line 41 . As soon as this moment is over, the computer 25 can be allowed to process the information from the sensor 40 .

As mentioned earlier, the invention can be applied to the case where the series 36 of bars are printed on a sticker label instead of a correspondence piece read through a window: the same problem occurs with a label where the edges of the label can be mistaken for coded marks. Because the invention uses the position of the window or label as a means of indicating to the computer whether the signal from the read head should be ignored or not, any additional need for position tolerance directly narrows the edge area in which the read head can operate accurately. Thus, in a label application, it would be important that the label be positioned exactly on the envelope.

The series 36 of bars 37 can be set to always contain a set number of bars, in which case the computer can be programmed to search for that exact number and then ignore any other signals. However, it is preferred in the invention that the computer be programmed so that the processing of signals from the counter continues only for a given offset of the envelope after the start of processing, that is, the signal to which the computer is directed processing of the reading sensor output stops, simply that the envelope has traveled a given preset distance since the computer started processing the reading sensor output. In this process, it is not possible that the trailing edge 39 of the window could be detected as if it were a bar 37 , and in this process there is no requirement that all of the unique series 36 of bars in all of the envelopes passing through have the same number of beams should have.

As for printing the markings on the envelopes, the general rule is that post offices specify the distance 47 that is required between the leading edge 46 of the envelope and the start point 48 of the series 49 of typically fluorescent markings 50 . The moment at which the envelope 28 enters the printing station 17 is signaled to the computer by the printing station photocell 26 ; the computer can be programmed to start printing once the envelope has traveled a predetermined distance thereafter.

It can be noted that the distance specified by the post office between the leading edge 46 of the envelope (ie, the edge which activates the photocell 26 ) and the point at which series 49 has to start is always in most areas of responsibility will be the same regardless of the size of the envelope. Therefore, the print station photocell 26 can remain at a fixed location relative to the print line 56 at the print station ( Fig. 8). In contrast, it will be recalled that the photocell 24 in the reading station 16 is adjustably movable relative to the reading line 41 to accommodate the possibility that the windows 28 may be loaded with envelopes at a different distance from the leading edge 46 of the Envelope than the windows of another cargo. Of course, if the need arises, the position of the photocell 26 at the printing station can be made adjustable in the same way.

It should be noted that it would be inadvisable to allow only one photocell to be used to control the operational start points of both stations because the distance 45 between the leading edge of the window and the leading edge of the envelope changes more frequently than the distance 47 and regardless of this between the beginning of the series 49 and the leading edge of the envelope.

It is possible to provide adjustability for the various operating points at the stations, either by the preferred method of moving the reading station photocell or, alternatively, by reprogramming the computer if adjustment is needed to respond to a new value for a measured offset . It is recognized in the invention that the former is much easier than the latter - all that the technician who has to adjust the device has to do is to ensure that he follows this rule that he distance 57 of the photocell 24 from reading line 41 sets the distance 45 from the leading edge of the envelope to the leading edge of the window (plus C, where C is a device dependent constant dimension). As mentioned, the technician need not reposition the corresponding photocell 26 at the printing station 17 for each envelope size because the distance 47 between the leading edge of the envelope and the starting point 48 of the fluorescent markings produced at the printing station is generally required to be constant.

The construction and operation of the reading sensor 14 will now be described with particular reference to Figure 4 of the drawings.

The reading sensor 40 comprises a housing 58 which is connected to the parallelogram connection 59 , through which the housing is guided for an up-down movement. The parallelogram connection is held by a block 60 which is attached to the upper track frame 4 .

A resilient slider 64 is attached to the housing 58 and has dimensions such that it acts with tension against the upper surface of an envelope 28 that passes under the reading sensor 14 . The housing 58 also encloses a pair of legs 65 , each of which has a ball bearing 67 mounted on its foot. The bearings 67 also act on the top surface of the envelope, but there is essentially no spring force between the bearings 67 and the housing 58 .

A suspension unit 68 is provided in connection with the parallelogram link 59 , the purpose of the suspension unit 28 is to act in conjunction with the weight of the housing 58 to produce the desired downward force on the envelope.

Housing 58 contains a lens 69 and an optical sensor or photodetector 70 , such as a silicon Photo Darlington transistor. The housing also contains floodlights 73 . The lens 69 and detector 70 are mounted in a focusing tube 74 which can be moved vertically in the housing 58 and locked at the height at which the detector is focused on the envelope.

To assist in focusing, detector 70 can be removed from tube 74 and temporarily replaced with a standardized light source. A spot of light from the source then appears on a test sheet placed under the sensor and the height of tube 74 can be adjusted until the spot is focused.

When an envelope 28 enters the reading station 16 , the leading edge 46 of the envelope grazes the ball bearing 67 , thereby forcing the housing 58 upward and onto the envelope. In another device, the ball bearing 67 can be omitted, if desired, so that the weight of the housing 58 is borne solely by the sliders. The resilient slider 64 presses down slightly on the envelope. The primary purpose of the resilient slider is to smooth the fill 30 , first to smooth out any wrinkles that may be present in the fill and second to ensure that the fill is in direct contact with the paper of the pull 35 .

The function of slider 64 is actually critical to the accurate operation of the device. A crease in the fill 30 may not seem significant to a person because the eye ignores it, but the photodetector 70 will detect a crease only too easily, as if the crease were one of the bars 37 . Therefore, the filling should preferably be perfectly smooth and flat. No less important is the requirement to ensure that the fill 30 is pressed into firm contact with the paper underneath when reading scanning takes place: if the filling 30 were even slightly raised from the paper below, the resulting light scattering could cause false readings.

The suspension unit 68 should therefore be such that the combined effect of the weight of the housing and the action of the spring in the unit 68 ensures a tight fit. However, the potency should not be too strong, or the envelope would tend to be distorted. Such distortion, if it occurred, would interfere with the smooth passage of the envelope through the reading station, and one of the objects of the invention is to create as little resistance to the movement of the envelope as possible because such interference would limit the throughput rate.

Gloss and reflections from the transparent material of the fill 30 can be difficult if not handled carefully and can either give a false indication that a bar is present or prevent a bar from being detected. The resilient slider 64 is therefore only provided with a small hole 62 , so that only a small portion of the potentially glossy filling is exposed during reading. The interior of the focusing tube 74 is blackened, as is the top surface of the slider 64 to minimize gloss. The floodlights 73 are set at an angle to minimize unwanted reflections from the window and surface of the paper.

The parallelogram connection 59 is important in achieving the desired degree of accuracy in the functioning of the sensor. It could be contemplated that housing 58 could be mounted on a single swing arm, unlike the two parallel arms as shown, and such an arrangement is contemplated. However, the position of the fulcrum of such an assumed single arm on the frame 4 would be critical: if the fulcrum were too high, the curved movement of the arm in operation would mean that when the housing 58 pivots upwards, the housing will also move slightly horizontally forward would be offset relative to hole 62 in the slider. If the fulcrum were a substantial distance above the envelope, such a mistake would not be negligible. Such an effect could be alleviated if the fulcrum were low down, at or near the height of the envelope, or if the arm were long, but there is little space in the device for such measures to be taken, particularly because it is generally a requirement is that the reading sensor 40 is also adjustable in its lateral position to ensure that the window is not always in the same lateral position on the envelope.

In the preferred parallelogram arrangement, the pivot points between block 60 and link 59 are fairly high above the envelope as shown, and the link is fairly short, and virtually no longitudinal movement accompanies the up / down movement of the housing.

The envelope thickness can vary in the range of approximately 1 to 5 mm. The suspension unit 68 is adjustable and it is usually desirable for the technician to adjust the adjustment of the suspension unit 68 in accordance with the nominal thickness of a particular pass of envelopes; the distance by which the housing 58 is caused to rise when the envelope passes underneath is thereby kept to a minimum. Block 60 tends to jump very slightly upward when the envelope passes underneath if suspension unit 68 is set correctly.

The two legs 65 and their ball bearings 67 should preferably be sufficiently far apart from one another that the bearings are sufficiently away from the filling.

The block 60 is slidable laterally in a groove in the upper track frame 4 to adjust the sensor in accordance with the location of the window 29 on the envelope 28 . Such a lateral adjustment device is enriched by virtue of the fact that the sensor 40 is located in front of the belts 5 , 7 .

The first code contains a number of bars indicating the post code and also a parity check: a count is made of the "post code" bars of the first code and a number of other bars printed in the code so that a number of all Bar in the code is from a selected first parity. Thus, a correct first code, as presented to the read head, should have this selected first parity. If, when reading the first code, a count of the bars of the first code reveals that the code is of a second different parity, this is detected by the computer 25 and a command is sent to "stop" the printer and a signal becomes one downstream envelope rejection device is sent to reject the incorrectly encoded envelope, that is, no second code is printed on the envelope and the envelope is rejected. The envelope can then be re-entered manually. When testing the device, the rejections at this stage are approximately 5 per 1000 envelopes processed, and are usually caused by poor loading.

The construction and operation of the printing station 17 ( Fig. 5) will now be described.

Two printers 75 are provided at the printing station 17 . These are mounted in a carriage 76 which is mounted on a parallelogram link 78 for up / down movement relative to a block 79 . The block 79 is attached to the upper track frame 4 .

Each print head 75 includes a dot matrix print unit 80 . This printing unit is a conventional stand-alone item, such as an Epson LX800, and will not be described in detail. Such units are readily available with either 9 or 24 needles. Arranged along the printing unit 80 and on the same printing line 56 , a cam roller 81 is provided, the axle bolt of which is firmly connected to the carriage 87 . The printing unit 80 and the cam roller 81 are arranged to be supported on a stop roller 82 , the axle bolt of which is firmly connected to the lower track frame 3 .

A band 94 is threaded below the printing unit 75 . Ribbon 94 contains ink that is to be detected by the automatic mail sorting device used by the post office and is typically fluorescent, black or other colored ink and is housed in a conventional ribbon receiving cartridge 95 . The belt is continuously circulated by a motor 96 . (The tape has been omitted in Figs. 5 and 8.)

The weight of the cartridge 76 , with the print heads 75 attached to it, is partly suspended on an adjustable spring unit 83 . A leg 84 and attached bearing assembly 85 is provided which is the same as that described with respect to the reading sensor 40 and which also takes up part of the weight of the cartridge. The entire weight of the cartridge is thus divided between four support points: the two cam rollers 81 , the bearings 85 and the spring unit 83 . In addition, when the print heads 75 are actuated, the actuation forces act on the needles in the two print heads against the weight of the carriage. In other embodiments, the bearing 85 can be omitted.

Of these, the operating forces are of course the Needles the main; and actually they will other weight-controlling supports arranged that the operating forces of the needles are correct Level of sensitivity and response controlled can be.

When an envelope 28 traveling along the tray 97 enters the printing station 17 (from the right, FIG. 5), the leading edge 46 of the envelope acts on the bearing 85 , drives the leg 84 upward, and lifts the carriage 76 . The parallelogram link 78 ensures that the sled remains horizontal during the upward movement, and so remains as the envelope passes under the sled. It is desirable that the two printheads 75 be positioned at exactly the same height above the envelope being passed, and this requirement applies, although the envelope thickness may vary. An angle adjustment means 86 is included as part of the sled and operates in conjunction with the parallelogram link 78 , whereby the angle of the sled can be adjusted relative to the link. The purpose of the leg and its bearing is to raise the sled sufficiently before the printing process actually begins: after its sudden rise, which may be accompanied by momentary bouncing, the sled then has time to adjust itself gently to its correct level, sufficiently before printing begins.

As noted, the print needles in printheads 75 are arranged to strike the envelope, acting against the serve roller 82 . The envelopes pass through the printhead at speeds in the range of 50 cm per second. Printheads have been developed for use in dot matrix printers in which the printhead moves much more slowly relative to the paper during printing; and one of the features of the invention is the recognition that a dot matrix printhead can be used in a manner so different from that for which it was developed. To handle the high relative speed, steps are taken to allow the printhead to move easily with the passing envelope during the moment the needles hit the envelope, as will now be described.

As shown in FIG. 8, the printing unit 80 is firmly screwed to a rail 87 . The rail 87 in turn is screwed between a pair of thin resilient arms 89 which depend downward from a block 90 which is screwed to the carriage 76 . The effect of this arrangement is that print head 75 has some "compliance" and can move (slightly) in the direction of envelope travel. Also, the fact that the reaction roller 82 moves with the envelope, but provides a firm base against which the needles can strike, provides a very advantageous way of printing. It can be noted that exceptional clarity of print is not needed and, in fact, the individual dots are preferably allowed to flow into one another, but smearing must be checked to ensure that each fluorescent bar 50 is clearly recorded.

The bars 50 typically have a width or thickness as generated by five needle strokes. Thus, to produce a bar 50 , the needles are actuated five times - if nine needles were provided, the needles would alternate in a 5-4-5-4-5 sequence.

As mentioned, the reason that two printers 75 are provided is that finished dot matrix printheads are normally only 3 mm high, whereas the fluorescent bar 50 must be 6 mm high. The two printheads are offset by a 3 mm difference. Thus, the first printhead prints the bottom halves of the bars 50 and the second printhead prints the top halves of the bars 50 . Of course, it is important that the two halves of the beams match each other exactly, and a suitable intermediate adjustment means (not shown) is provided.

A verification reader 200 ( FIGS. 2 and 3) can be provided downstream of the printing station 17 , which can have any suitable shape and which reads the bars read by the print heads. The signal received by the reader is compared to the input data to the printer. If there is an error in the printed code, a signal is sent to the computer 25 to notify an envelope reject device downstream of the reader 200 to reject the incorrectly encoded envelope. This property serves as a quality assurance property for detection and immediate action to reject an envelope or stop processing if the error is caused, for example, by a faulty printhead, printer ribbon, or a mechanical problem during transport or offset.

As stated above, the reading sensor 40 is designed to be laterally adjustable because the position of the window can vary. The printheads 75 , on the other hand, do not have to be laterally adjustable because it is required that the fluorescent bars are always the same distance from the edge of the envelope.

The demands of different post offices can  cause the fluorescent bars on are different places, however, would return as soon as the device once for a given positioning the fluorescent bar was developed, the Printheads stay in place. It is unlikely that there would be a need Build device that meets the requirements of more than a post office, however, such a Adjustment can be provided if desired.

The device shown in the drawings is easy to maintain because of its construction. The upper track frame 4 is able to swing around the conveyor belt drive pulley 99 . After unlocking a suitable lock (not shown), the upper track frame 4 can be swung upwards, together with all components attached to it, including the upper conveyor belt 5 , and the reading and printing stations 16 , 17 . As a further maintenance aid, the printing station 17 is mounted on a mounting plate 98 , which is locked onto the upper track frame during operation, but can swing up for maintenance around an axis parallel to the direction of travel of the envelope with respect to the upper track frame .

The modular construction of the device is evident. Most of the components are designed by one individual screw to be held in place.

As for the spacing of the fluorescent bars 50 , this may be the same as the pitch of the ink bars 37 ; alternatively, the encoded pattern of bars 50 may be different from that of bars 37 . The distance is preferably smaller for the first code; 1/4 and 1/2 inch spacing is desired between the right window edge and the first bar to allow the insert to move and the window edge signal to clear, and the last bar should be spaced from the left window edge. In conventional window envelopes, these needs will usually require that the first code be "compressed" relative to the second code.

8-10 illustrate a somewhat different printing station 100 for use with an apparatus in accordance with another aspect of the present invention. The printing station 100 is equipped with two print heads 102 (only one is shown in FIGS. 8 and 10 and no print head is shown in FIG. 9), which are separately mounted on a carriage in the form of a printer plate 106 . Each printhead 102 is mounted on a respective U-shaped printhead plate 108 , 100 . Each plate 108 , 100 is mounted on the printer plate 106 by a parallelogram connection for up / down movement relative to the plate 106 . Each link includes a pair of pivotable arms 112 , 114 .

The arms 112 , 114 are mounted on the plate 106 via stationary support pins 116 , 118 . Pins 120 , 122 extend from the other ends of arms 112 , 114 in front of plate 106 (as seen in FIG. 8) to the rear of plate 106 and an arm of the respective printhead plate 108 , 110 . The other arm of each plate 108 , 110 is provided with a pin which acts as a spring washer 120 , 122 . The springs 124 , which act on the washer 122 , are formed from flat steel strips and extend from spring holders 125 on the printing plate 106 . The springs are arranged so that an upper spring 124 a resists an upward movement of the plate 108 , 110 , and thus also the print head, while the lower spring 124 b dampens the downward movement.

The printer cartridge (not shown) is mounted on the front of the printing plate 106 and is driven by a clutch 126 and an electric motor 126 mounted on the back of the plate 106 .

The plate 106 is mounted on the device frame by an adjustable pivot bracket 129 on one side of the plate 106 , and is provided with an adjustable bearing part 130 .

The print heads 102 , 104 of this embodiment operate similarly to the print heads described above.

An alternative construction in the invention is being considered is that the read and print heads under the Tray are positioned in the lower track frame, and act upwards. This arrangement would have the advantage that the read and print heads could remain stationary,  when the envelope happens: curve rolling in the upper track frames are mounted, could move around to record the thickness of the passing envelope. Even though therefore the construction of the reading and printing stations such an arrangement is not simplified preferred because in this arrangement the envelopes with the Face down: other postal ones Machines require the envelopes to face are up so that reversers would be needed.

Another alternative in which the happening Envelopes are face up, too arrange the envelopes under the tray happen and up in contact with the tray be pressed. Again, this would be the measure Avoid needing the read and print heads swim, however the difficulty now is that the ideal effect - that is, gravitation - to hold the Envelopes in position on the tray are not available would be.

The conventional dot matrix print heads as mentioned print only a height of about 3 mm, which is why two Printheads in the preferred embodiment are provided. However, in the invention, one alternative arrangement contemplated wherein the needles in the Printhead operating with a relatively wide The strikers are engaged. In this arrangement when the needles are actuated, the movement of the Mechanically transfer needles to the impact beam, which then through the printing tape on the envelope  beats. In this case, only one printhead would be needed however, there is a disadvantage in the fact that the additional inertia of the striker Speed and the response of the printing process would slow down.

Claims (37)

1. A method of coding correspondence to simplify the routing of correspondence to a destination by an automatic mail sorting device, comprising the steps of:

• a) marking a letter with an easily machine-readable first code corresponding to the human-readable postal code of the destination address;
• b) inserting the letter into a window envelope so that the first code is positioned in the window;
• c) machine reading the first code in the window;
• d) printing a machine-readable second code corresponding to the first code and the human-readable postal code of the destination address at the location and in the format as used by a particular automatic goods sorting device so that the envelope is suitable for processing by the device.

2. The method according to claim 1, characterized in that the first Code is a bar code.   3. The method according to claim 1, characterized in that a correct second code a parity element includes and is of a first parity, and that if the read parity of the second code is up an envelope has a different second parity, a rejection signal to identify the Envelope for later separation from the envelopes, which carry a second code of the first parity, is produced. 4. The method according to claim 1, characterized in that the first and second codes are of the same format. 5. The method according to claim 1, characterized in that reading the first code and printing the second code is carried out during the envelope and the letter along an envelope path from one Conveyor device by a reading and a Printing device are performed. 6. The method according to claim 1, characterized in that the first Code on the letter in conventional black ink printed simultaneously with the destination address becomes. 7. The method according to claim 1, characterized in that the  second code on the envelope in fluorescent Ink is printed. 8. The method according to claim 1, characterized in that the second code from a pair of dot matrix printers is printed, with a printer a lower part of the code prints and the second printer prints an upper one Part of the code prints. 9. The method according to claim 1, characterized in that the first Code on the letter adjacent to the Destination address is marked on the letter. 10. The method according to claim 1, characterized in that the first Which is read by an optical sensor is effective in a series of electrical signals To generate compliance with the code which Signals in a sequence of apart Pulses are arranged, and the second code of a printer in the form of apart Markings in sequence in accordance with the pulses originating from the optical sensor is printed. 11. The method according to claim 10, characterized in that the Envelope offset on the envelope path monitored will and in electrical signals according to the  Offset of the envelopes is implemented, and this electrical signals with the electrical signals be coordinated by the optical sensor. 12. The method according to claim 11, characterized in that the electrical signals from the optical sensor be locked until after the leading edge of the Window of an envelope the optical sensor Happened. 13. The method according to claim 1, characterized in that the part of the window through which the first code is read will, while reading the code against the letter is pressed. 14. A method of encoding correspondence to facilitate routing of correspondence to a destination by an automatic mail sorting device, comprising the steps of:

• a) marking of a shipment with an easily machine-readable first code corresponding to the human-readable postal code of the destination address;
• b) machine reading the first code;
• c) Printing a machine-readable second code corresponding to the first code and the human-readable postal code of the destination address in one place and in a format as used by a special mail item sorting device.

15. An apparatus for printing encoded marks on an envelope in accordance with pre-printed marks relating to the envelope, wherein

• the device comprises a reading station and a printing station and a conveyor for transporting the envelope therebetween along a conveyor line;
• the reading station comprises an optical sensor which is effective to produce a series of electrical signals in accordance with the pre-printed markings;
• a calculation means accepts signals of the offset of the envelope by the stations and coordinates the reading and printing stations;
• the device comprises means for transmitting the electrical signals from the optical sensor to the computer and means for arranging the signals in a sequence of spaced pulses;
• - The printing station comprises at least one signal-controlled printer which remains at a fixed printing point at the printing station during normal operation of the device;
• and the printer is effective to print a mark on the envelope when the envelope passes the print point and to print a series of such marks on the passing envelope in a spaced-apart sequence in accordance with the pulses received by the transmission means.

16. The apparatus according to claim 15, characterized in that

• - The printing station is provided with a printing station offset counter, and the reading station is provided with a reading station offset counter;
• - And each counter is effective to measure the linear offset of a passing envelope relative to the stations.

17. The apparatus according to claim 16, characterized in that

• - The device includes means for converting the measurement of the two counters into electrical signals according to the offset of a passing envelope;
• the device includes means for coordinating these electrical signals with the electrical signals from the optical sensor;
• the coordination is such as to ensure that the distance and the positioning of the coded marks printed by the printer on the envelope are equivalent to the pre-printed marks as read by the optical sensor.

18. The apparatus according to claim 17, characterized in that

• the print counter comprises a print station wheel and the read counter comprises a read station wheel, each wheel being mounted for rotation about a respective fixed axis;
• - Each wheel is arranged for operational intervention with a passing envelope;
• - And the arrangement is such that the angular offset of each wheel around its axis comprises a measure of the linear offset of the envelope passing through the respective stations.

19. The apparatus according to claim 17, characterized in that

• - the envelope has a window and the pre-printed markings on a correspondence piece are legible through the window and the window has a leading edge;
• - and the device includes means for blocking electrical signals from the optical sensor with respect to a particular passing envelope until after the leading edge of the window of that envelope has passed the optical sensor.

20. The apparatus according to claim 15, characterized in that

• - The envelope has a window and the window includes a filling of transparent material through which the pre-printed markings can be read;
• during normal operation of the device, the optical sensor remains at a reading point on the reading station, the reading point being fixed in the longitudinal sense relative to the conveyor line;
• - the reading station includes a means for pressing a zone of the filling of transparent material against the correspondent;
• - The pressed zone comprises at least the part of the filling that is currently at the reading point when the envelope passes the reading point.

21. The apparatus according to claim 20, characterized in that

• - The means for pressing the reading zone comprises a resilient slider which is mounted for engagement directly with the filling;
• - The resilient slider comprises a length of resilient sheet material;
• - And the material is bent, the convex side of the bend being directly engaged with the filling.

22. The apparatus according to claim 21, characterized in that

• - The slider is provided with a hole through which the marks on the correspondence are visible to the optical sensor;
• - And the hole is essentially small, which minimizes gloss and reflections from the filling.

23. The device according to claim 15, characterized in that

• - The device comprises a fixed conveyor tray, the arrangement being such that when the envelope runs on the tray, the pre-printed markings are on top;
• - The optical sensor is positioned over the tray;
• the device includes means for mounting the optical sensor for up / down movement;
• - And the device includes a means for lifting the optical sensor, the means operationally responsive to the presence of an envelope that passes along the tray.

24. The device according to claim 23, characterized in that

• - The means for lifting the optical sensor includes a storage means which can be engaged with the passing envelope;
• - The bearing means is substantially rigid with respect to the optical sensor;
• - The storage means is positioned in the device so that the optical sensor is lifted sufficiently from the passing envelope before the markings pass under the optical sensor.

25. The device according to claim 23, characterized in that the agent for mounting the optical sensor for a Up / down movement includes a means to Limitation of the optical sensor accurately to one constant vertical orientation if the optical Sensor makes an up / down movement. 26. The device according to claim 25, characterized in that the Means for restricting the optical sensor Parallelogram connection includes. 27. The apparatus according to claim 15, characterized in that the Device means for applying tension includes the passing envelope if the Envelope passed through the reading station. 28. The device according to claim 27, characterized in that the Means for applying tension two separate Drive means for conveying the envelope through the Device includes one leading and one pulling is positioned with respect to the reading station, wherein the leading drive means with a lower Speed as the pulling drive is operated. 29. Device for printing fluorescent bars on an envelope, wherein

• - The device comprises a conveyor for conveying the envelope through the device, along a conveyor line;
• - the bars are not less than H mm high, measured at right angles to the conveyor line;
• - The bars are arranged in a series apart along the conveyor line;
• the device includes two printheads, each having an effective print height of no more than H mm, each printhead having a means for printing fluorescent ink on the envelope;
• the device includes a computer for coordinating the printing of the two printheads;
• - The two print heads are mounted in the device so that they are not laterally movable laterally with respect to the envelope during printing;
• - The conveyor is arranged so that the envelope is not laterally movable laterally with respect to the printheads during printing;
• - The two print heads are arranged side by side along the conveyor line, and are slightly laterally offset laterally;
• - each bar being printed in two parts, one from each printhead.

30. The device according to claim 29, characterized in that the Printheads are dot matrix printheads, and H = 3 mm is.   31. The device according to claim 29, characterized in that

• the conveyor includes a tray which is arranged so that the envelopes pass face up along the tray in a horizontal orientation;
• - The device includes a carriage to which the printheads are attached;
• - the device includes a means for mounting the carriage for an up / down movement;
• and the device includes a means for lifting the sled, the means operatively responsive to the presence of an envelope passing along the tray.

32. Apparatus according to claim 31, characterized in that

• - The device includes two stop rollers, which are positioned so that the compressive forces act on the envelope due to the activity of the respective printheads;
• - And the stop rollers are mounted in the device so that the forces are counteracted substantially without springback.

33. Device according to claim 31, characterized in that the Means for lifting the carriage so in the device is positioned that the carriage of the passing envelope is lifted sufficiently before the two printheads begin to print the bars.   34. Device according to claim 32, characterized in that the Means for mounting the sled for one Up / down movement includes a means to Restriction of the sled to a constant one Orientation with respect to the vertical during the Up / down movement. 35. Device according to claim 33, characterized in that the Sled restriction device one Parallelogram connection includes. 36. The apparatus of claim 15 in combination with the Device according to claim 29. 37. Apparatus according to claim 26 in combination with the Apparatus according to claim 35.