EP1183155A1

EP1183155A1 - Franking machine

Info

Publication number: EP1183155A1
Application number: EP01905559A
Authority: EP
Inventors: Werner Haug
Original assignee: Frama AG
Current assignee: Frama AG
Priority date: 2000-02-23
Filing date: 2001-02-22
Publication date: 2002-03-06
Anticipated expiration: 2021-02-22
Also published as: WO2001062504A1; US6973433B2; AU782076B2; US20030007820A1; AU8156301A; ATE277770T1; WO2001062506A1; US6910766B2; CA2368358A1; US7255422B2; AU782136B2; EP1200268A1; EP1200268B1; AU782070B2; DE50102191D1; ATE265934T1; DE50103192D1; CA2368355A1; US20030016981A1; EP1183154A1

Abstract

The invention relates to a franking machine, comprising a print head of an ink-jet printing mechanism for printing flat postal items such as letters or postcards, which can be introduced into said mechanism or which pass through the same. Said franking machine consists of a guiding part which is located around the print head and projects in relation to the nozzle opening plane of said print head, and with which a conveying device is associated, said conveying device transporting the postal items between itself and conveying rollers lying opposite and rotating about axes that are located crosswise to the conveying direction. Said conveying device has two drive-connected driving rollers which together with the guiding part, form a path of travel. The driving rollers are located in front of and behind the print head in relation to the conveying direction. A reversibly liftable counter pressure roller located opposite exerts a pressure on each driving roller, respectively, or on a postal item being transported in-between. A roller feeler (39, 119) which is driven by the passing postal item and which is associated with an encoder device (122) is located between the driving rollers (13, 15; 127, 113) in order to monitor the speed and position of a postal item being transported or for controlling the pressure on a postal item.

Description

franking machine

The invention relates to a franking machine with at least one print head of an inkjet printing unit for printing insertable or continuous flat shipping objects such as letters or postcards, consisting of a guide part which is arranged above the print head and opposite its nozzle mouth plane and which has the shipping objects between them and opposite them transversely to Axes arranged in the conveying direction are assigned to rotating conveying rollers of a conveying device transporting the shipping objects, the conveying device having two drive-connected drive rollers forming a conveying section with the guide part, which are arranged in front of and behind the printhead when viewed in the conveying direction and that one opposite each other against a driving roller or one in between transported shipping object is a pressure-exerting, reversibly liftable counter-pressure roller is arranged in franking machines today in addition to the classic rotation technology ik is increasingly using new stamp application methods, including those based on thermal and inkjet

Experience shows that not only the printhead has to be replaced, but depending on the printing technology, the entire franking machine structure is larger and very complex, ie also correspondingly expensive changes and Is subject to adjustments.

Inkjet or inkjet printheads have been known for a long time and are used in particular in PC printers. The knowledge gained there when using such printheads cannot be transferred to the present field of application in franking machines. The reasons include in the high speed of the letters to be franked, their different formats and thicknesses, as well as the significantly harsher environmental conditions, due to the partly dirty surfaces of the shipping objects. In addition, these franking imprints often have to meet the strict quality requirements of the post offices, which requires a high level of construction and reliability.

The present invention is based on the object of ensuring in a franking machine that the printing unit allows trouble-free printing and a clearly identifiable print image when franking shipping objects such as letters, cards or the like with different thicknesses, different formats and materials. Since such machines have to enable high throughputs nowadays, fully automatic operation is also required. Since from thinnest objects (quasi single sheet) to thick letters a wide range of shipping objects with different mechanical properties - for example due to the bending behavior - and to be printed or franked in a wide variety of formats, the printing process must be carried out with the throughput speed or be coordinated or checked with the route covered by the shipping object. In addition, conditions must be created that ensure high reliability and low-maintenance construction.

According to the invention, this object is achieved in that, for speed and position monitoring of a transported shipping object. for tax tion of the pressure on a shipping object, a feeler wheel driven by the passing shipping object and assigned to an encoder device is arranged between the drive rollers

This means that simple means can be used to achieve a high level of precision when printing on the shipping objects

The functions and design of an embodiment of the franking machine according to the invention are described below

For a better understanding, reference is made to the reference numerals and figures in which embodiments of the invention are shown

1A front cam for right counter pressure roller

1 B rear cam for right counter pressure roller

2A front cam for left counter pressure roller

2B rear cam for left counter pressure roller

3 main shaft

4 rear side wall

5 front side wall

6A counter pressure lever, left, front

6B counter pressure lever, left, rear

7A control lever, left, front

7B Control lever, left, rear

8A counter pressure lever, front right

8B counter pressure lever, right, rear

9A control lever, right, front

9B control lever, right, rear

10 axis for counter pressure lever and control lever

11 stop bolts for counter pressure lever on the right

12 connecting bolts for counter pressure lever on the left

REPLACEMENT SHEET RULE 26 Counter pressure roller, right, support roller Counter pressure roller, left A Swing arm, front for support roller B Swing arm, rear for support roller Axle for swing arm Spring suspension rod Spring suspension Tension spring for control lever Support roller support with push arm, rocker arm, worm shaft, worm wheel Fork light barrier Slotted disc Switch cam for main shaft basic position Micro switch, control roller Tension spring for counter pressure lever, DC motor, drive roller, right Driving roller, left, right roller Stop for rocker arm Tension spring for rocker arm Stop for push arm Extension wheel for incremental encoder hold-down plate resp. Guide part drive motor for feed

REPLACEMENT BLADE (RULE 26) / 0116

41 Gear units for drive rollers

42 incremental encoder, encoder

43 Boom on the support roller support

Description of the contents of the drawing in the following figures

Figure 1 Front view of the complete counter pressure mechanism, including

Drive, feeler wheel and main shaft drive,

FIG. 2 top view of counter pressure mechanism,

FIG. 3 front view of the complete counter pressure mechanism in the franking position, counter pressure in the upper position,

FIG. 4 front view of the complete counter pressure mechanism in the service position,

Back pressure in the lowest position,

FIG. 5 front view, position of the counterpressure lever / rollers with a thicker short letter inserted or from the automatic feeding of the letter arriving from the right under the right drive roller,

FIG. 6 front view, thick letter under all drive rollers and the feeler wheel,

Figure 7 Front view, thick letter has left the right roll, the right one

Counter pressure roller automatically comes to the upper position, middle support roller remains at the original height level. The left counter pressure roller has taken over the height sensing and

Figure 8 top view, drive rollers with feed gear.

In the case of single letter franking, the letter is inserted manually into the franking machine. Photocells start the franking process with an exact envelope position. The counter-pressure rollers, which are in a lower position when the envelope is inserted, are moved upwards via the control cams of the main shaft and press the mail item against the upper drive rollers. The letter transport resp. the franking process is triggered. The counter pressure consists of two counter pressure rollers and an intermediate the support roller. The counter pressure rollers are located under the right and left drive rollers. The support roller has the task of keeping the letter under the print heads at the required height level without pressing the letter against the end faces of the print heads, so that the printed image remains unsmeared. After franking, the counter-pressure rollers and the support roller move down again and open the gap for inserting a new envelope.

In addition to the insertion and franking position of the counter pressure rollers and the support roller, there is also a "Service" position. In this position, the counter pressure rollers are moved down further to make room for the service station. The service station cleans and closes the printheads during long breaks. It is also required for filling the print heads when changing the ink bag.

A plurality of control cams 1A, 1B and 2A, 2B are arranged on the main shaft 3, which pivot the control levers 7A, 7B and 9A, 9B via the control rollers 29 about the axis 10, more or less depending on the necessary position. The basic position of the main shaft 3 is found by a microswitch 28 connected via the control cam 27. The worm gear 23/24 is driven by the motor 31 and the main shaft is rotated into the "insert letter", "franking" or "service" positions. The exact position is achieved via a fork light barrier 25 and the slotted disk 26 seated on the motor shaft by electronic control. The counter pressure levers right and left 6A, 6B and 8A, 8B are pivoted upward about the axis 10 by the tension springs 30 attached to the control levers 7A, 6B and 9A, 9B until the counter pressure rollers 13, 15 on the upper drive rollers 32, 33 issue. The control levers 7A, 7B and 9A, 9B reach their end positions via the control cams 1A, 1B and 2A, 2B, which has the consequence that the tension springs 36 are biased a little further. The secure support between the control rollers 29 and the control curves 1A, 1 B and 2A, 2B is achieved by the tension springs 29 attached to the spring suspension rod 18. The exact lower position of the counterpressure levers 6A, 6B or 8A, 8B is achieved by the stop bolts 11, 12 located on the control levers, which are supported on the counterpressure levers after a slight idle stroke and drag them downward. The corresponding positions are shown in detail in the figures.

The support roller 14 located in the middle, which brings the letter at an exact distance from the ink jet print heads, is rotatably mounted on two support roller supports 21, which in turn are supported by two parallelogram arms 16A, 16B. The rocker arm 22 seated on the axis of rotation of the support roller 14 is suspended in the axis 34 of the right counter-pressure rollers 13 and must forcibly move downwards when the right counter-pressure lever 6A, 6B is lowered and reaches the level of the right counter-pressure roller. The rocker arm 22 is rigidly supported on the stop 35 against the support roller carrier 21 by rotating to the left. To the right, the rocker arm 22 can turn away from the stop 35 against the force of the tension spring 36. This is necessary because of the mutual scanning between the right and left counter pressure roller and will be described in more detail later.

Description of Figures 1 to 8:

The counterpressure levers are ready in the basic position for inserting a single letter. As soon as the letter is in its exact rear and right position on the table stop, the franking machine is activated via a reflex light barrier. First, the main shaft 3 rotates clockwise by about 1/3 of a turn. The control levers 7, 9 are pivoted upwards via the control rollers 29 by the control cams 1, 2. The counter pressure levers are also moved upwards via the tension springs 30 until the counter pressure rollers 13, 15 rest against the drive rollers 32, 33. The control levers move a little further until the Control curve has peaked. The possible overstroke of the control levers is compensated for by the spring-loaded coupling of the counter pressure levers. The support roller 14 has adjusted itself to the same level via the rocker arm 22. The letter is now clamped between the drive rollers and the counter pressure rollers. The drive motor 40 (see FIG. 8) drives the drive rollers 31, 33 via the gear 41 and moves the letter from right to left. The speed and position are detected via the incremental encoder 42 and the feeler wheel 38. The feeler wheel is driven by friction from the moving envelope and thus detects the exact speed of the letter surface. The letter is pressed onto the feeler wheel via a separate counterpressure, which will be described separately later. Depending on the position of the letter, the inkjet print heads spray corresponding patterns from cell to cell, which in turn lead to the desired print image. The hold-down plate resp. Guide part 39 holds the letter at an exact distance from the face of the print head in order to be able to obtain a clean print image with regard to resolution and also to prevent the printed lines from being smeared when the envelope is moved. After the franking process has ended, the drive motor 40 switches off and the main shaft 3 rotates back into its basic position, the counterpressure levers 6A, 6B; 8A, 8B return to their starting position. A new letter can be inserted. The main shaft 3 rotates between the "insert" and "franking" positions only about 1/3 of a turn back and forth, which brings a considerable time advantage and also protects the mechanics. After another 1/3 turn, the counter pressure rollers have reached their absolutely lowest position, as is necessary in the service position (see Figure 4). Back to the basic position "insertion" again only 1/3 turn is required.

FIG. 5 shows the function of the rocker arm in connection with the right counter pressure roller. The necessity of this function is described below

REPLACEMENT SHEET RULE 26 wrote. The starting point is a relatively thick short letter that is inserted manually. The franking machine triggers the franking process. The counter pressure levers move up as described. The thickness of the short letter limits the stroke of the right counter pressure roller upwards. The letter is clamped between the upper, right drive roller 32 and counter pressure roller 13 via the spring force of the tension spring 19 that builds up. This is necessary in order to guarantee a slip-free drive. If the support roller 14 were not automatically brought to the same height level via the rocker arm 22, the thick envelope between the hold-down plate fixed above, respectively. Guide part 39 and the support roller are pinched, which leads to transport problems and loss of print quality. However, the support roller carrier with the support roller is brought to the level of the right counter pressure roller via the rocker arm 22 already described. The support roller carrier moves downwards in a parallelogram-like manner with the right counter-pressure roller and the envelope can pass the printing station smoothly.

In the illustration shown in Figure 6, the thick letter is also moved under the left drive roller 15. The left counter pressure lever also had to move downwards against spring force and assumed the same level as the right counter pressure roller or the middle support roller. The stop 37 of the left counterpressure lever has made contact with the push arm of the support roller support 21.

In Figure 7, the letter has left the right drive roller and the right counter pressure lever moves up again until the counter pressure roller touches the upper drive roller. The stop 37 of the left counter-pressure lever rests on the extension 43 of the support roller carrier 21 and now holds it at the original height level. The right rocker arm 22 can fold out counter-clockwise and the attachment point can follow the right counter pressure roller until the counter pressure

REPLACEMENT SHEET RULE 26) roller rests on the upper right drive roller. The height sensing of the support roller takes place alternately between the right and left counter-pressure roller and thus guarantees the optimal, friction-free distance to the printheads and hold-down plate or over the entire letter length. Guide part 39.

101 counter pressure lever for driven incremental encoder

102 Rotation axis for counter pressure lever

103 stop pin as drag stop to control lever 105

104 stop edge to stop pin 103

105 control lever

106 Connection bracket for intermediate wheels

107 Link plate to the axis of the left counter pressure roller

108 driven friction wheel to incremental encoder wheel

109 Friction wheel to left counter pressure roller

110 idler gear

111 Between wheel

112 Between wheel

113 Drive roller on the left

114 counter pressure roller left

115 Gear unit for feed drive

116 Tension spring between the incremental counter pressure lever and the control lever

117 Axle of the left counter pressure roller

118 axle for idler gear

119 Touch wheel for incremental encoders

120 counter pressure lever left

121 encoder disc

122 encoders

123 axis for encoder disc

124 ball bearings

REPLACEMENT SHEET RULE 26 125 Friction pairing of drive roller 113 and friction wheel 109

126 Friction pair of friction wheel 108 and feeler wheel 119

127 Driving roller on the right

128 counter pressure roller right

129 jockey wheel

130 letter

131 axle for friction wheel

Contents of the drawing for the following figures:

Fig. 9 front view of the complete counter pressure mechanism, including

Drive, driven incremental encoder counter pressure, feeler wheel and main shaft drive. Counter pressure lever in the "manual insertion" position,

Fig. 10 front view of the complete counter pressure mechanism, including

Drive, driven incremental encoder counter pressure, feeler wheel and main shaft drive counter pressure lever in the top position "Franking",

11 + 12 back pressure mechanism,

13 + 14 isolated, driven counter pressure mechanism of the incremental encoder,

15 front view, letter is under the right drive roller and has not yet reached the feeler wheel, feeler wheel is driven indirectly via the left drive roller, friction wheels and idler wheels,

16 + 17 back pressure mechanism,

Fig. 18 front view, envelope under both drive rollers, feeler wheel directly from

Letter surface driven,

Fig. 19 Front view, envelope has left the right drive roller, drive is now via the left drive roller, feeler wheel driven directly from the surface of the letter,

REPLACEMENT BLADE (RULE 26) 20 top view of complete counter-pressure mechanism,

Fig. 21 Development of the driven incremental counter pressure in

Section and Fig. 22 - 24 Details on the Tatrad with encoder.

Because of the short letter problem and the space required for the print heads, printing rollers of a franking machine, in particular an inkjet printing unit, require drive rollers so that the envelope is always clamped under a drive roller during the printing process. The right drive roller drives the envelope when it enters the printing area, the left roller takes over the drive when it exits the printing area. The speed or position monitoring of the envelope on one of the two rollers would have the disadvantage that the short letter would therefore no longer be monitored within a certain path section at the beginning or at the end of the envelope. For the quality of the printed image, it is also necessary to know the exact letter speed. A speed detection on a driven shaft would have the disadvantage that the letter speed is not necessarily detected if, for example, the letter has a transport slip or is stopped or if a jam problem occurs. In the device described here, speed and position monitoring is carried out via a separate feeler wheel that drives an encoder disk directly. The encoder disk or the feeler wheel are located exactly between the drive rollers, in the middle of the two print heads. The signals are evaluated via an encoder. The exact starting position when inserting the letter manually is provided by a reflex light barrier that detects the position of the right edge of the letter. In the case of automatic letter feeding, this zero point signal is delivered by a fork light barrier of the peripheral automatic feeding. From this start signal, the touch wheel must scan the exact position of the letter. Since the letter has not yet reached the Tatrad when zero point is triggered when it is inserted manually or when it is automatically fed, it must therefore drive for a short time Distance via the driven button counterpressure. The driven counter pressure roller is pressed against the feeler wheel or the left drive roller via the cam-controlled mechanism of the remaining counter pressure levers or rollers. The speed of the left drive roller is transferred to the feeler wheel via two friction wheels and several intermediate wheels. The left and right drive rollers are firmly coupled via a spur gear, so that the speed of the letter driven by the right roller matches the speed of the left drive roller. Small differences are irrelevant here, since printing has not yet started. As soon as the letter - for example a short letter - driven by the right drive roller, gets under the feeler wheel, the speed of the driven counter pressure no longer plays a role. The feeler wheel is driven at the same speed via friction between the letter surface and the feeler wheel circumference. The counter pressure wheel, which previously acted as a friction wheel drive, now only has a pressing function, since the envelope has been pushed between the friction partners. Depending on the letter length or the label length, the printing process begins in the letter position intended for this. Depending on the respective envelope position, the print heads inject line-by-line patterns that lead to the corresponding overall print image. After a certain distance, the envelope leaves the right drive roller and is only moved by the left drive roller. The feeler wheel scans the speed until the end of the letter. Printing is completed approximately 10 mm before the end of the envelope.

The counter pressure lever 101 of the driven incremental encoder is rotatably supported on the axis of rotation 102 riveted to the side wall. The counter-pressure lever is moved up and down in conjunction with the other counter-pressure levers. This function is described separately. The counter pressure lever 101 is moved up and down over the riveted stop bolt 103 and through the stop edge 104 of the control lever 105. The overstroke of the control lever is compensated for by the tension spring 116 until the friction wheel 108 bears against the feeler wheel 119.

E SÄTZBL TT RULE 26 The friction wheel 108 is rotatably supported on the riveted axis of rotation 131. The left counterpressure lever 120 and the counterpressure lever 101 are rotatably connected to one another via two connecting straps 106, 107 and guarantee constant center distances with a simultaneous degree of freedom for the connecting gear. The friction wheel 109, which sits on the same axis 117 as the counter-pressure roller 114, is driven by the left drive roller 113 (friction pairing 125). The friction wheel 108 is driven at the same speed via the spur gears 112, 111, 110 (friction pairing 126). When the postage meter machine is triggered, the counterpressure levers rise until the corresponding counterpressure rollers are in contact with the drive rollers or the feeler wheel. At the beginning of the franking process, the short letter is driven only by the right drive roller 127 and pressed by the right counter pressure roller 128. The feeler wheel is driven by the gear chain from the left drive roller via friction and idler wheels to the feeler wheel up to the point in time at which the envelope between the friction wheel 108 and the feeler wheel 119 arrives. As soon as the letter is under the feeler wheel 119 and is pressed by the friction wheel 108, only the speed of the surface of the letter is important for the peripheral speed of the feeler wheel. This means that the exact letter speed is detected. The scanning surface of the feeler wheel (lateral surface) can be roughened, knurled or the like to increase the grip.

In the case of automatic feeding, the driven counter pressure of the incremental encoder also has the advantage that the feeler wheel does not have to be accelerated by the letter arriving from the feeding. This point is not important for manual feeding, since all rotating parts are accelerated from standstill at the same time.

The feeler wheel 119 sits together with the encoder slotted disk 121 on the axis 123, which is supported by means of two precision ball bearings. The encoder 122 samples the signals and passes them on to the control electronics. The quality of the Sampling the letter speed and the position is of enormous importance for the print quality. The chronological sequence of the spraying of the line-by-line print pattern occurs depending on the letter speed and thus the letter position.

Claims

Franking machine with at least one print head of an inkjet printing unit for printing insertable or continuous flat shipping objects such as letters or postcards, consisting of a guide part arranged above the print head and opposite its nozzle mouth level, one of which has the shipping objects between them and opposite, in order to cross them Axes arranged in the conveying direction are assigned to rotating conveying rollers of a conveying device transporting the shipping objects, the conveying device having two drive-connected drive rollers forming a conveying section with the guide part, which are mounted in front of and behind the print head when viewed in the conveying direction, and opposite each one against a drive roller or an intermediate one transported shipping object is a pressure-exerting, reversibly raised counter-pressure roller, characterized in that for speed and position monitoring of a transported V sand object or A control wheel (38, 119), which is driven by the passing shipping object and is assigned to an encoder device (122), is arranged between the drive rollers (32, 33; 127, 113) to control the pressure on a shipping object.

Machine according to claim 1, characterized in that the encoder device (122) is connected to a controller connected to a computer.

Machine according to one of claims 1 or 2, characterized in that the feeler wheel (38, 119) is drive-connected to the drive roller (33, 113) connected downstream in the conveying direction.

Machine according to claim 3, characterized in that on the side of the counter-pressure roller (15, 114) cooperating with the drive roller (33, 113), a counter-pressure lever (6A, 6B; 120) with the drive roller (33, 113) drive-connectable friction wheel (109) is provided which drives a further friction wheel (126) which is drive-connected to the feeler wheel (38, 119) via a gear train formed from intermediate wheels. 1 0116

18

Machine according to claim 4, characterized in that the further friction wheel (126) with the counter pressure roller (15, 114) is mounted on a multi-part lever (101) and can be displaced against the spring wheel against the feeler wheel (38, 119).