Abstract:
A mail processing apparatus has a field table and a printer disposed above the feed table for printing indicia on a mailpiece moved in a movement direction along the feed table. A start sensor detects a leading edge of the mailpiece and supplies a signal to a microprocessor controller that operates the printer, in order to initiate a printing event on the mailpiece. An ejection roller is disposed following the printer and is operated by a motor to eject the mailpiece from the printer. An end sensor is disposed near the ejection roller and detects a trailing edge of the mailpiece, and supplies a signal to the microprocessor controller that causes the microprocessor controller to disconnect the voltage from the motor that operates the ejection roller.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention concerns an arrangement for a printing mail processing apparatus according that increases the throughput of mailpieces. The invention can be used in franking machines and in similar printing, accounting or mail processing apparatuses. 
   2. Description of the Prior Art 
   U.S. Pat. No. 4,746,234 And East German Patent 233 101 B5 disclose a thermotransfer franking machine having a mailpiece transport path with a start sensor that detects the leading edge of a mailpiece, i.e., the start of a letter envelope, and which is connected with a microprocessor in order to start a printing procedure as soon as a mailpiece arrives in the printing station. A thermotransfer printhead is equipped with a shift register, a memory latch unit and driver unit as well as with a series of thermoprinting heating elements disposed orthogonal to the mailpiece transport direction. The thermotransfer printhead is connected with the serial data output of the microprocessor via a register. The microprocessor controller can advance the ink ribbon corresponding to the transport speed mailpieces by means of signals from an encoder. 
   U.S. Pat. Nos. 4,767,228, and 4,886,384 and European Application 189 984 disclose an ink ribbon cassette for thermotransfer franking machines with a window for the application of a friction wheel to the ink ribbon and a mailpiece transport device as is used in similar form in modern thermotransfer franking machines of the type T1000 and Optimal® of Francotyp-Postalia. When a flap for the cassette bay is opened, a simple mechanism is actuated and the friction wheel is moved away from the ink ribbon of the cassette, allowing the cassette to be removed. 
   U.S. Pat. No. 5,710,721 and European Application 716 398 disclose an internal franking machine circuit connected with a first microprocessor controller circuit that is the same for all franking machines. The internal franking machine circuit allows the connection of a variable number of sensors and actuators corresponding in type and number to the franking machine type. An adaptation to different printing methods is enabled by the use of different application-specific circuits (ASICs). Production piece numbers for franking machines of the same type, however, in order to justify the cost of the mask programming of the ASICs. 
   In thermotransfer franking machines of the type T1000 and Optimal®, an encoder disc is fastened on the same axle as a friction wheel and is consequently likewise rotated corresponding to the rotation of the encoder wheel when the ink ribbon is advanced. The operation of the machine is interrupted if an ink ribbon transport does not occur or after the passage of a predetermined time after a franking. This is also called the ejection phase. Up to 25 mailpieces with a maximum thickness of 5 mm can be franked per minute. When the franking event has ended, the microprocessor of the franking machine can check, by means of the start sensor whether the mailpiece (for example the letter envelope) has been transported into the printing region. The start sensor is positioned on the leading edge of the transport path, and the microprocessor thus can detect whether the letter envelope is still lying on the leading edge. It can occur that, due to rotation of the letter envelope, during the franking the letter envelope no longer actuates the start sensor, so the letter envelope is no longer detected during and after the franking. The microprocessor thus can no longer definitely detect with the start sensor whether the letter envelope has already exited the franking machine. If the ejection event were ended due to the interrogation of this start sensor, the letter envelope could remain in the franking machine or could repeatedly trigger the start sensor if it executes an unusual movement, for example with the trailing edge of the letter envelope. This has conventionally been addressed by an (in principle) long ejection phase (without interrogation of the start sensor), but this leads to a lower mailpiece throughput of the franking machine. 
   The use of additional sensors in order to increase the throughput of mailpieces is known from United States Patent Application Publication No. 2004/0021755, in which mailpieces are transported faster before and after the printing. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to provide a sensor in a printing mailpiece processing apparatus and to connect it with the controller so that the throughput of mailpieces of different lengths can be increased. An internal interface circuit connected with the microprocessor controller should also be achieved more cost-effectively with an increased number of sensors/actuators. 
   The above object is achieved in accordance with the present invention in a mail processing apparatus having a printer operated by a microprocessor controller to execute a printing event on a mailpiece that is moved, such as by motorized movement, on a feed table past the printer. The apparatus has a start sensor that detects a leading edge of the mailpiece, during the feed of the mailpiece, and emits a signal to the microprocessor controller causing the microprocessor controller to initiate the printing event. The apparatus has a motor-operated ejection roller disposed following the printer that interacts with the mailpiece to eject the mailpiece from the printer. The apparatus has an end sensor disposed near the ejection roller that detects the end (trailing edge) of the mailpiece and emits a signal to the microprocessor controller causing the microprocessor controller to disconnect voltage from the motor that operates the ejection roller. 
   In printing mail processing apparatuses, the mailpieces are transported relative to the printhead. For establishing the duration of the ejection phase of the printing mailpiece processing apparatus, the mailpiece with the largest dimensions (for example a letter envelope length of the format B4) conventionally had to be taken into account. Starting from the goal to shorten the ejection phase, to allow the printing mailpiece processing apparatus to be more quickly ready after a printing, to print a subsequent letter envelope, the invention makes use of a (letter envelope) end sensor that can detect when the mailpiece (letter envelope) has actually exited the printing mail processing apparatus. The ejection phase is ended after this detection and the (letter envelope) start sensor can be interrogated again. The length of the ejection phase thus is dependent on the letter envelope length, and the next letter envelope can already be detected earlier in order to start printing of the following letter envelope earlier, in the event that the length of the present letter envelope is not maximum. 
   The end sensor is positioned in the region of the ejection roller of the printing mail processing apparatus, and a circuit for interrogation of the end of a mailpiece by means of an end sensor has an electrical connection of the end sensor, via a special, programmable printing controller component, with the microprocessor controller. For such a special, programmable printer controller component, the cost of the mask programming of an ASIC are justifiable given higher piece counts at the printing mail processing apparatus. For small piece counts at the printing mail processing apparatus, however. that is not profitable. Therefore a different programmable logic that is universally spatially and temporally effective is used. While the spatially-effective programming (for example field programming) establishes the inner structure of the logic, the process and the order of the data processing of logic gates within the logic are defined by the temporally-effective programming. The invention is explained herein in an example of a franking machine, but it is not limited to this use alone. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a known thermotransfer franking machine, showing with the flap of the cassette bay. 
       FIG. 2  is a perspective view from the front and upper right of a thermotransfer franking machine of the next generation. 
       FIG. 3  is a perspective view of the thermotransfer franking machine with opened cassette flap. 
       FIG. 4  is a block diagram for the controller of a thermotransfer printer with an end sensor for interrogation of the end of a mailpiece, in accordance with the present invention. 
       FIG. 5  is a perspective view of the shaped cassette bay part from the front and lower right. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  shows a perspective view of a known thermotransfer franking machine  1 * from the front and upper right. The thermotransfer franking machine  1 * of the type Optimail® has a start sensor  16 * (indicated dashed since it is covered) underneath a cassette bay in the feed table  4 *. The start sensor  16 * supplied a signal to a microprocessor, but from this signal the microprocessor cannot definitively detect whether the letter envelope has already exited the franking machine. The franking machine is equipped on its right side  7 * and on its upper part  10 * with a flap  5 * for the cassette bay of the franking machine  1 *. The flap  5 * has an activation field  50 * at its opening. The transport of a mailpiece to and from the franking machine  1 * ensues on the feed table  4 * on the transport edge  49 * on the front side of the franking machine  1 *, from left to right. 
     FIG. 2  shows a perspective view from the front and upper right of a thermotransfer franking machine  1  of the next generation. The thermotransfer franking machine  1  is equipped on its right side  7  and on its upper part  10  with a flap  5  for the cassette bay of the franking machine  1  and on its left side with a weighing plate  2  of a scale component. The flap  5  has an activation field  50  at its opening. All housing parts are manufactured, for example, of colored plastic. The transport of a mailpiece to and from the franking machine  1  ensues on the feed table  4  of the franking machine on the front side of the franking machine  1 , from left to right. 
     FIG. 3  shows a perspective view from the front and upper right of a thermotransfer franking machine  1  with an opened flap  5 . The flap  5  is shown opened in the direction toward the upper part  10 . The flap  5  has flap arms at both sides on its underside. On one side, the right external housing wall  6  on the cassette bay merges on the right side  7  into the right side wall of the upper shell of the franking machine and, on the other side, into the right cover  60 . Upwardly directed steps  62  are provided that correspond to the flap shape on its underside. On the other side, the left external housing wall  3  on the cassette bay merges into the upper shell of the franking machine and, on the other side, into the left cover  30 , further upwardly directed steps  32  are provided that correspond to the flap shape on its underside. Upon closing of the flap, the arms of the cassette flap  5  project into a corresponding slot-shaped opening in the steps  32  and  62  of the left cover  30  and the right cover  60 , respectively. On its underside, the flap  5  moreover has a flap finger  53  serving as an actuator for a mechanism that detects the position of the flap by means of a sensor (not visible). The travel of the flap during opening thereof is designed so that sufficient time is provided for deactivation of the supply voltage  14  (see  FIG. 4 ) for a chip reader unit before extraction of the ink ribbon cassette  8  is possible. 
     FIG. 4  shows a block diagram for control of a thermotransfer printing with end sensor for interrogation of the end of a mailpiece. A microprocessor  21  is connected, in terms of addresses, data and control, with at least one non-volatile memory  22 , a pixel memory RAM  23 , a fixed value memory FLASH  24  as well as with a printer controller component  28 , via a bus  25 . An encoder  64  is connected with the print data controller  261  of the component  26  in order to synchronously initiate the buffering of the binary pixel data and the printing of the print image gaps. For data input/output, an interface controller  262  of the component  26  is connected with the chip reader unit  14 , and with a motor  65  for actuation of a conveying device for mailpieces in the transport direction. The interface controller  262  also is connected to a motor  66  for actuation of an axle for a take-up reel of the ink ribbon cassette; and with a motor  67  for actuation of an activation device for a counterpressure roller. The interface controller  262  also is connected on the other side with sensors, such as the start sensor  16 , end sensor  19 , an activation sensor  36  for detection of the flap position/encoder position and an activation sensor  68  of the activation device. A printing procedure is started and a franking is executed when a leading edge of a mailpiece is detected by the start sensor  16 . The end sensor  19  is disposed downstream (in terms of mail flow) at a distance from the start sensor  16  and detects the successive passage of the leading edge and then the trailing edge of a transported mailpiece. Corresponding sensor signals arrive at the microprocessor of the microprocessor controller  20  which disconnects a motor operation voltage of the motor  65  by means of the printing controller component  26 , the motor  65  serving both for actuation of the conveyance device for mailpieces in the transport direction and for actuation of the ejection roller  15 . Moreover, a motor operating voltage of the motor  66  for actuation of the take-up reel axle is disconnected. 
   A thermotransfer printhead  9  is equipped in a known manner with a register, a memory latch unit and driver unit as well as with a series of thermotransfer printing heating elements disposed orthogonal to the mailpiece transport direction. The thermotransfer printhead  9  is connected via the register with the serial data output of the print data controller  261  which, given a direct memory access, on the input side, receives 16-bit parallel binary print image data from the bus  25  and, on the output side, emits serial binary print image data. 
   The encoder  3  is connected with the print data controller  261  (if applicable via the interface controller  262 ) in order to synchronously initiate the buffering of the binary pixel data and the printing of the print image gaps, whereby the printhead  9  is activated with a clock frequency that allows a transport speed of approximately 150 mm per second for mailpieces up to 6 mm thick. 
   The primary control circuit board of a franking machine moreover has further interfaces (not shown), for example for connection of a keyboard and a display unit, a chip card write/read unit, a modem as well as, if applicable, a security module (which is also designated as a PSD (Postal Security Device)). However, the PSD can be omitted for pure printing tasks. 
   The printer controller component  25  can be realized either as an application-specific circuit (ASIC) or by programmable logic such as, for example, the field programmable gate array (FPGA) chip component of the series Spartan-II 2.5V by the company XILINX (www.xilinx.com). A use of the FPGA allows the costs of the mask programming of the ASICs to be spared. 
   An FPGA is an integrated circuit that contains many thousands of identical logic cells as standard components (up to 50,000 in the XC2S50 by the company XILINX). Each logic cell can independently adopt any of a limited set of properties. The individual cells are interconnected by a matrix of the conductors and the programmable switch. The design needed by a specific user is introduced by the simple logic function for each cell being specified and the switch selectively locks in the linkage matrix. Complicated designs are facilitated by these fundamental blocks being combined in order to create the desired circuit. These blocks form field-programmable means that have the advantageous function of being defined by a program of the user instead of by the manufacturer of the device. The program is either burned-in permanently or semi-permanently as a part of the board configuration process, or is loaded from an external memory at each time when the aforementioned printing device is activated. The configuration data for the FPGA XC2S50 encompass approximately 0.6 Gbit and are stored in the fixed value memory FLASH  24  ( FIG. 4 ). The use of an FPGA chip and technologies associated therewith offer the advantage that the programmable logic saves development costs and time relative to an ASIC design that is complicated to an increasing degree and the grid count per FPGA chip has now reached counts that allow the implementation of ever more complicated applications. This allows a large degree of programmer freedom in hardware and software, whereby CAD tools decide which parts of a source code program should be executed as software and which parts should be executed as hardware. 
   Furthermore, the circuit arrangement of the component  26  can be realized by means of conventional technology, i.e. as a hard-wired circuit of logic gates of positive and/or negative logic. 
     FIG. 5  shows the perspective view of a shaped cassette bay part from the front and lower right. A respective mechanism located under the cover and gradations of the upper housing shell rests (in a manner not shown) on the chassis between the left inner housing wall  172  and the right inner housing wall  171  and the left and the right external housing wall on the shaped cassette bay part  17 , while associated sensors are supported on respective integrally-molded sensor carriers  174  and  175 . The sensor  36  for detection of the cassette flap position/encoder position is supported on the sensor carrier  174  (externally, integrally-molded on the left inner housing wall  172 ) of the shaped cassette bay part  17 . The inner chamber (cassette bay) of the shaped cassette bay part  17  is bordered by the right inner housing wall  171 , the left inner housing wall  172  and the rear housing wall  173 . A molding  1731  on the edge between the left inner housing wall  172  an the inside of the rear housing wall  173  forms an outer wall of a channel for a slider, of which only its top slope  434  is visible. A quadrilateral opening  1732  in the rear housing wall  173  accommodates the chip reader unit  14 . A circular opening  1733  in the rear housing wall  173  is provided for the winding mandrel (not shown) of the cassette coil. The left inner housing wall  172  has an opening  18  and a lateral guide  1721  for correct positioning of the cassette upon insertion. The right inner housing wall  171  likewise has a lateral guide. An upper housing wall  176  likewise has guides  1761 ,  1762  as a positioning aid. The upper housing wall  176  merges laterally into the left and right inner housing walls and to the rear into the rear housing wall  173 , and not only stabilizes the cassette bay, but also has integrally-molded fasteners (covered) for a spring-biased locking element  11 , at the free end of which a pressure element  12  is integrally molded. A frame  177  for the printhead  9 , which frame  177  protrudes into the inner space of the cassette bay, is integrally molded on the lower end of the rear housing wall  173  in its center. The space formed by the lateral integrally-molded sensor carriers  174  and  175  is sealed at the bottom by a base plates  178 ,  179  that are each integrally-molded on the rear housing wall  173  between the left and right inner housing walls  172  and  171 . For low-friction mailpiece transport, it is advantageous for the base plate  178  to gently ascend relative to the feed table and ends (downstream in terms of the mail flow) in a thickened edge  1781  before the frame  177  for the printhead. Furthermore, for the ejection of the mailpieces it is advantageous for the base plate  179  to begin after the frame  177  with a thickening  1791  which accommodates and bears un-driven rollers  1792  and  1793  such that they can rotate. 
   The end sensor  19  here rests on the sensor carrier  175  integrally-molded on the right on the shaped cassette bay part  17 . The activation element of the end sensor  19  is fashioned as a sensor actuation lever  191  that is arranged on a rotation axle  190  of the end sensor  19  such that it can move in a rotary fashion counter to an elastic force and is connected with a leg of a torsion sprint  194 . In the mounted state, the trigger end of the sensor actuation lever  191  lies next to or at the end of the ejection roller  15 . Opposite the trigger end of the sensor actuation levelr  191 , the sensor actuation lever  191  passes into a disc  192  which is scanned by a sensor electronic. The sensor electronic is housed in the sensor electronic housing  193 . For example, a sensor of the type Photointerrupter LG-413L by the company Kodenshi Corp. can be used. 
   As an alternative to the arrangement on the lateral integrally-molded sensor carrier  175  of the shaped cassette bay part of the upper housing shell, the end sensor  19  can be arranged in the lower housing shell below an opening in the feed table. In that case it has a sensor actuation lever  191  shaped so that its trigger end is positioned in the region of the ejection roller  15 . The trigger end preferably extends to near the ejection roller  15  or at the end thereof. 
   The sensor actuation element can be a spring-biased, rotatable sensor actuation lever  191 . Instead of this other implementations are also conceivable as a sensor actuation element in order to detect a movement. The torsion spring  194 , if applicable, can be omitted. 
   The microprocessor controller  20  is connected with the motor  65  for actuation of a transport device for mailpieces as well as with the further motors  66 ,  67  of the mail processing apparatus via a controller in the programmable printer controller component  26 . Given a controller equipped with a field-programmable printer controller component, in principle an adaptation to any mail machine types with different numbers of sensors and actuators and motors is economically possible, even given small piece counts. 
   Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventors to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of their contribution to the art.