EP2072272B1 - Transport device for flat goods that are to be printed - Google Patents

Description

The invention relates to a transport device for flat goods to be printed according to the preamble of claim 1. The invention is used in microprocessor-controlled printing devices and is suitable for franking machines and other mail processing devices. The invention makes it possible to achieve a small offset of the dots in the printing, which in particular improves the machine readability of an impression of a franked mailpiece.

A transport principle with an overhead belt and a bottom-mounted sprung counter-pressure device, between which a mailpiece is clamped, is known from the patent DD 233 101 B5 However, a thermal transfer ribbon is not suitable as a conveyor belt. The thermal transfer ribbon is disposed above a feed table over which the mail pieces are transported horizontally post-downstream. The feed table has openings through which a driven counter-pressure roller passes through the mail item.

A transport principle with an overhead conveyor belt and a bottom-mounted sprung counter-pressure device, between which a mailpiece is clamped, is from the European patent EP 1 079 975 B1 (or FR 2790997 ) known. A first transport belt looped between two rollers is arranged above a feed table, over which the mail pieces are transported horizontally. The post-downstream roll of the first conveyor belt is its drive roller. Between the two rollers two deflection cylinders are arranged, wherein the one downstream arranged deflection cylinder for adjusting the belt tension is adjustable by means of a screw. The feed table has openings through which pass upstream and downstream ever a spring-loaded counter-pressure roller on the mail item. A second belt passes over these suspended counter-pressure rollers and at least one non-suspended roller and a drive roller of the second conveyor belt.

From the patent US 6,550,994 B2 (or US 2003016986 ) a mailing machine with a mail piece transport device is known, with which the letters are transported by means of an overhead conveyor belt and a plurality of lower-mounted sprung levers through the postage meter. The same goes out US 5,813,326 . US 6,776,089 B1 and US 6,585,433 B2 out. The conveyor belt is looped on rollers but does not allow the pressure module or part thereof to protrude into the area between the rollers. The width of the conveyor belt is relatively small and is about 1 inch. The extension of the housing transversely to the mail item transport direction is relatively large in comparison. In addition, a second printing position is provided for the printing of the franking strips, which are rolled up on rolls and which are unrolled for printing. This second printing path causes higher production costs.

in the US 5,467,709 For example, a printing device for an ink-jet franking machine has already been proposed, wherein a franking print is printed by means of an ink-jet print head on a mail piece in the case of an approximately horizontal letter transport. The ink jet print head is stationary behind a guide plate in a recess for printing arranged. As a transport device is a revolving conveyor belt, which is also arranged on the side of the guide plate. On the other side opposite to the guide plate, a supporting and pressing device is arranged with a plurality of rollers, so that a fed mail piece between the rollers of the support and pressure device and the circulating conveyor belt is clamped. However, the device can not avoid skewing the print carrier. Even an insufficiently tensioned conveyor belt or not exactly parallel alignment of the axes of those rollers on which the conveyor belt rotates, carries the aforementioned danger in itself. Due to the large number of roles of support and pressure device latter is very expensive.

In the DE 196 05 015 C1 ( US 5,949,444 ) Is already an embodiment of a printing device of an inkjet franking machine JetMail ^® & Co. has been proposed by the applicant FP Mailing AG, a franking is carried out at a non-horizontal, approximately vertical letter transport by means of an ink jet printhead, the stationary behind a guide plate in a recess is arranged. As a transport device is a revolving conveyor belt with pressure elements for the mail pieces (letters to 20 mm thickness, DIN B4 format) or for franking strips, which are formed aufklebbar on packets of any thickness. The print carrier (letter, postcard, franking strip) is clamped between the pressure elements and the guide plate.

Even simpler constructed transport and drive devices without counter-pressure device ( DE 196 05 014 C1 ) or with counterpressure device ( WO 99/44174 ) near the printing area of at least one inkjet printhead. The latter is in WO 99/44174 arranged downstream of a feed roller pair in the transport direction, wherein the upper roller is driven and the lower counter-pressure roller is sprung. Another pair of rollers post-downstream of the ink-jet printhead near the ejector also exerts a force on the print carrier. The print area is spaced more than one radius of the respective driven roller from the power transfer area of one of the pairs of rollers. The printing information can be transmitted through a digital In principle, although printing can be changed in all areas, high-quality printing is difficult the higher the transport speed is. In particular, when using two ink-jet print heads, an offset in the print image (connection error) along a print length in the transport direction can occur, which complicates the machine evaluation of the print image. The force effect of the further pair of rollers post-downstream of the inkjet printhead near the ejection leads to different path lengths and thus in the case of two mutually offset ink-jet printheads to the connection error in the printed image. The print quality demanded in the context of current programs of the postal carriers - for example the Information Based Indicia Program of the USPS - would thus only be achievable with a low printing speed. Another disadvantage is the small thickness of the print carrier, which can be printed by such a simple design printing device.

One from the EP 1 170 141 B1 Known device for printing a print carrier in the printing area uses in the power transmission area a driven transport drum and non-driven counter-pressure rollers or alternatively a non-driven counter-pressure conveyor belt. A stationary ink jet printhead prints in the print area the downstream moving print carrier, wherein the ink jet print head is arranged axially to the transport drum. The printing area is preferably about 1 inch and is spaced from the power transmission area, wherein the distance of the farthest pixel from the edge of the transport drum is smaller than the radius of the circumference of the transport drum. The disadvantage, however, is the low approximately linear contact of the mail piece surface to be printed with the transport drum and a spaced feed wheel for mailpieces. The feed wheel is driven by a toothed belt from the transport drum. This causes a Δx offset of the dots in the print image. Othogonal this results in a Δ y offset of the dots in the printed image, especially in very large mailpieces. The structure also causes high manufacturing costs.

In the market segment of franking machines with small to medium Mailgutdurchsatz a compact transport device for mail pieces with the lowest possible production cost is needed, which is easy to remove

The invention has for its object to develop a transport device in a printing device for flat goods, which ensures a high print quality at a mean throughput of flat goods in cooperation with a microprocessor-controlled printing device.

Despite low production costs, the reliability of the printing device should be as high as possible and the printing offset in the x and y directions should be low. On the one hand postcards and on the other hand letters of the format C4 or B4 with a mail piece thickness up to 10 mm are to be processed.

The conveyor belt should be easy to change. A cost-effective design with simple assembly of a guide and support device for a conveyor belt for transporting the flat goods should allow easy adjustment for adjusting the tape track and ensure safe storage of roles on which the conveyor belt runs. The optimal belt tension should be set automatically.

The object is achieved with the features of the arrangement according to claim 1.

A printing module is arranged counter to the direction of gravity over a printing window in the z direction of a Cartesian coordinate system. During printing, a print image is generated by at least one print head. For example, at least one print head of an ink cartridge ejects ink droplets opposite to the z direction in the direction of gravity through the print window. The printing window is arranged on the edge of a conveyor belt in a housing part, wherein the conveyor belt transports a flat good to be printed in the edge region during printing in the transport direction x past the at least one print head. The flat goods are pressed against the force of gravity to the conveyor belt in a support area.

Empirically it has been shown that a support region is advantageous, which is on both sides of a line, which is centered through the printing window transversely to the transport direction x in the y direction of the Cartesian coordinate system runs, is extended. The conveyor belt is supported on a support plate which is arranged above the support and transport area between a molding plate and a bearing plate of a roller carrier, wherein the support surface of the support plate is larger than the surface of the pressure window, which is adjacent to the support plate.

The roller carrier consists of molding plates, the bearing plate, the support plate and a number of rollers for guiding the conveyor belt along a centrally indented oval curve. The conveyor belt is stretched taut in the indented section by means of a tension roller. To compensate for the effect of the clamping force a pull rod is arranged outside on the bearing plate. The indented portion is at least partially formed for receiving the belly of at least one ink cartridge of a printing module and shaped accordingly.

The bearing plate has a surface structure corresponding to a desired bending characteristic and carries at both ends on an inner side a number of spacers for fixing the molding plates and on an outer side clamping means for biasing the bearing plate.

The conveyor belt has a width in the y direction of the Cartesian coordinate system which is wider than the width of the printing window.

The mailpiece transport device has a flat belt as a conveyor belt, by means of which the guide is improved during transport of the mail pieces. The printing offset in the x-direction and y-direction is less than 100 μm in both directions.

By projecting the belly of the ink cartridge in the space created by the indentation and by omitting a second printing path for franking strips, the printhead is positioned relatively close to the conveyor belt edge when the printing module has been moved to the printing position. From the latter, the printing module can be moved in a conventional manner into a cleaning and sealing position by transverse movement means transversely to the mail piece transport direction. The cleaning and sealing position can advantageously be arranged close to the conveyor belt. This also reduced the size of the chassis and housing across the mailpiece transport direction.

The transport device is detachably mounted on the metal chassis of a drive device. The latter has at least one motor for driving the conveyor belt. The subdivision into a drive device and into a transport device advantageously enables an easily removable and compact transport device. A component of the transport device is the preassembled roller carrier, which is completed with the conveyor belt to the transport device. The roller carrier has at the post-current output end, i. at its right-hand end, a drive roller and a first idler pulley, and at the input end, i. at its left-hand end, an output roller and a second deflection or tensioning roller for a conveyor belt, which is looped in the mounted state by the rollers.

• kostengünstiger Aufbau und einfache Montage,
• sichere Lagerung durch eine einseitige Lagerplatte,
• stabile torsionsarme Lagerung der Formteilplatten,
• optimale Transportbandspannung ist trotz einem leicht wechselbaren Transportbandes vorhanden,
• einfache Justage, zum Einstellen der Transportbandlaufspur.

It is envisaged that a first number of spacers on the one hand between one end of a bearing plate of the roller carrier and a first molding plate, that a second number of spacers on the other hand between another end of the bearing plate and a second molding plate are arranged, that a respective clamping means at the ends attached to the bearing plate of the roller carrier and is designed for power transmission of a pull rod, wherein for defined deflection of the roller carrier with a corresponding load of the bearing plate, a mechanical tension is transmitted via the clamping means on the two ends of the bearing plate, the one exerted by the conveyor belt on the roller carrier mechanical Counteracts tensile stress and wherein the pull rod clamping and adjusting means with which the tension can be adjusted.
The pre-assembled roller carrier has the following advantages:

• cost-effective design and easy installation,
• safe storage through a one-sided bearing plate,
• stable low-torsion bearing of the molding plates,
• optimal conveyor belt tension is available despite an easily exchangeable conveyor belt,
• easy adjustment, for setting the conveyor belt track.

A secure storage of the rollers is ensured by the fact that at the ends of the roller carrier two molding plates are provided which are mounted on a bearing plate via spacers, the bearing plate carries at each of its two ends in each case three spacers. Downstream post two shafts and a spacer column are provided as spacers. By the support of two molding plates in three points and a subsequent three-point mounting a stable and torsionsarme storage of the molding plates is achieved via the spacers at the two ends. Although a first and second molding plate is attached via the spacers each at the two ends of the bearing plate, but not on the metal chassis of the printing device. This lack of attachment of the molding plates on the metal chassis and a centrally inserted area to weaken the structure of the bearing plate of the roller carrier allows its deflection under appropriate load on the rollers by a first tensile force F1, which is exerted by the mechanical tension in a mounted conveyor belt. The first tensile stress F1 counteracts an adjustable second tensile force F2, which is applied by a mounted on the outside of the bearing plate tie rod.

The metal chassis is designed as a frame with a base plate, with two orthogonally angled side walls and two transverse bars which lie in the frame transversely to the transport direction x for flat goods and are stored in the y-direction depending on an inwardly angled right angle tab of a side wall. The bottom plate, the side walls and the two transverse rods are attached to a rear wall of the frame.

The two transverse rods each have at their other end remote from the rear wall a receiving means, for example in each case a receiving bore in the y-direction of their axes or other means.

The transport device is received via the aforementioned two receiving means, which are part of the crossbars of the frame and in the y direction, and fastened by means of releasable attachment frontally, for example by means of mounting holes of the crossbars or on the axes with external thread, preferably screwed. In addition, a drive shaft is provided parallel to the cross bar, which is respectively mounted in a bearing on the rear wall and the inwardly angled right angle tab of the right side wall of the frame, wherein a drive pinion is fixed to the rear wall remote from the end of the drive shaft. When the transport device is pushed onto the two receiving means, the drive pinion engages positively in a ring gear on the drive roller of the transport device. As a conveyor belt, for example, serves a flat belt. The fixed bearing shafts must not be arranged costly exactly parallel to the axis to each other. And the bearing plate does not need to be redesigned at a higher belt tension, because the tensile force F2 exerted by the tie rod compensates for the first tensile stress F1 and thus the deflection with correct adjustment. This advantageously allows a cost-effective and simple construction. There is no need to use additional adjustable belt track elements. All existing bearing shafts, on which the pulleys run, also act simultaneously as belt track elements.

Figur 1,

Draufsicht auf eine vereinfachte Darstellung einer bekannten Transportvorrichtung erster Art,

Figur 2,

Draufsicht auf eine vereinfachte Darstellung einer bekannten Transportvorrichtung zweiter Art,

Figur 3,

Draufsicht eine vereinfachte Darstellung einer Transportvorrichtung der vorgeschlagenen Art,

Figur 4,

Schnitt durch eine Vorderansicht der vereinfachten Darstellung einer Transportvorrichtung nach der Figur 3,

Figur 5,

Perspektivische Ansicht des Druckgeräts mit der vorgeschlagenen Transportvorrichtung, mit Chassis und mit Druckmodul in der Druckposition,

Figur 6,

Perspektivische Ansicht der vorgeschlagenen Transportvorrichtung und einer Antriebsvorrichtung der Transportvorrichtung des Druckgeräts von vorn rechts oben in gesprengter Darstellung,

Figur 7,

Perspektivische Ansicht der vorgeschlagenen Transportvorrichtung von hinten rechts oben in gesprengter Darstellung,

Figur 8,

Perspektivische Ansicht des Rollenträgers der Transportvorrichtung von vorn rechts oben,

Figur 9a,

Draufsicht auf den in y-Richtung konkav gebogenen Rollenträger der Transportvorrichtung,

Figur 9b,

Draufsicht auf den konvex gebogenen Rollenträger der Transportvorrichtung,

Figur 9c,

schematische Darstellung der Kräftewirkung.

Advantageous developments of the invention are characterized in the subclaims or are presented in more detail below together with the description of the preferred embodiment of the invention with reference to FIGS. Show it:

FIG. 1,

Top view on a simplified representation of a known transport device of the first kind,

FIG. 2,

Top view on a simplified representation of a known transport device of the second kind,

FIG. 3,

Top view a simplified representation of a transport device of the type proposed,

FIG. 4,

Section through a front view of the simplified representation of a transport device according to the FIG. 3 .

FIG. 5,

Perspective view of the printing device with the proposed transport device, with chassis and with printing module in the printing position,

FIG. 6,

Perspective view of the proposed transport device and a drive device of the transport device of the printing device from the front right top in an exploded view,

FIG. 7,

Perspective view of the proposed transport device from the rear right top in exploded view,

FIG. 8,

Perspective view of the roller carrier of the transport device from the front right top,

FIG. 9a,

Top view of the concave curved in the y-direction roller carrier of the transport device,

FIG. 9b,

Top view of the convexly curved roller carrier of the transport device,

FIG. 9c,

schematic representation of the force effect.

In the FIG. 1 Fig. 1 is a plan view of a simplified illustration 1 'of a known transport device of the first type, with the arrangement of rollers and ink cartridges removed for the sake of simplicity. A mail piece 10 'is pressed by a number of - from above not visible and therefore dashed lines - support strips SL1', SL2 'and SL3' from below to a conveyor belt 2 'and transported during printing in the transport direction x'. The width W1 of the conveyor belt 2 'in the y'-direction ortogonal to the transport direction x', is of the order of magnitude of a printing window 3 'for at least one print head. The mail piece 10 'is initially pressed by three support strips SL1', SL2 'and SL3' from below to the conveyor belt 2 '. The printing window 3 'is arranged in a known manner in a - not shown - housing part and is spaced from the support area. Under support area is that area to understand in which the mail piece the mailpiece transport device is pressed. In the course of mailpiece transport, the number of effective support rails decreases as the mailpiece is transported away from the support area. The resulting deteriorated leadership leads to an offset of the mail piece, wherein the offset mail piece drawn in dashed lines and the offset has been exaggerated for better clarity. Alternatively, the support strips are designed as sprung and pressable support wheels or rollers. The center of the printing window 3 'is indicated by a line 4', which is orthogonal to the transport direction x ', ie in the y'-direction and is spaced in the x'-direction from the support region.

In the FIG. 2 Fig. 2 is a plan view of a simplified illustration 1 * of a known transport device of the second type, wherein for the sake of simplicity the arrangement of ink cartridges has also been omitted. A mail item 10 * is pressed from below by a transport drum 2 * from below, by means of only one support bar SL *, which is not visible from above and therefore shown by dashed lines, and transported in the transport direction x * during printing. The width W2 * of the transport drum 2 * in the transverse direction, ie in the y * direction, is greater than that of a printing window 3 * for at least one print head. Alternatively, the support strips are designed as sprung and pressable support wheels or rollers. After one of the EP 1 170 141 B1 known device for printing a print carrier in the printing area, a driven transport drum and non-driven counter-pressure rollers or alternatively a non-driven counter-pressure conveyor belt is used in the power transmission area. The counter-pressure device consists of a sprung rocker with conveyor belt to increase the support area. The center of the printing window 3 * is indicated by a line 4 *, which also runs through the center of the support area. Their course is orthogonal to the transport direction x *, ie in the y * direction, because the print window 3 * is spaced apart from the support area or counterpressure area only in the y * direction, but not in the x * direction. Already the The latter measure reduces the offset of printed pixels (dots) in the x and y directions. The offset is at most 110 μm.

In the FIG. 3 is a plan view of a simplified representation 1 of a transport device of the type proposed shown. The center of the printing window 3 is again indicated by a line 4, which also extends through the middle of a support strip SL3. The conveyor belt 2 of the transport device and the pressure window 3 are adjacent here next. The offset .DELTA.x, .DELTA.y is reduced by another 10 to 30% when the mailpiece 10 is transported in the transport direction x during printing, if further support strips SL1, SL2 and SLn are pressed from below on a mail piece 10 on both sides of the drawn line 4, and when the conveyor belt 2 rests against the top of a support plate.

In the FIG. 4 is a section through a front view of the simplified representation 1 of the transport device according to the in the FIG. 3 proposed type shown. The conveyor belt 2 of the transport device is fed back via a medium-sized roller 5 and a large encoder and deflection roller 6 in a loop. By two more small pulleys 7, 8, the loop is indented in a central region. The conveyor belt 2 runs here above and below a support plate 9, which supports the conveyor belt 2 in that section which runs back to the driven medium-sized roller 5. In other words, the pulling strand of the conveyor belt is supported by the smooth support plate 9 at least from the middle of the mail piece transporting device in the transporting direction. The small guide roller 8 also serves as a tension roller for tensioning the conveyor belt 2. The non-driven large roller 6 is part of an encoder (not shown). A mail piece 10 is pressed by a number of support strips SL1, SL2, SL3 and SLn from below to the conveyor belt 2 and transported during printing in the transport direction x.

The at least one ink cartridge 11 is used in a microprocessor-controlled printing device with a printing window, through which the at least one inkjet printhead 11.2 of the at least one ink cartridge 11 injects ink droplets onto the surface of a mail piece 10 or flat goods to be printed. In a Cartesian coordinate system, the x-direction is the transport direction of the mail piece 10 or flat good, which is transported lying on the side not zubedruckenden. The y-direction points backwards to the back and z-direction up to the top of the microprocessor-controlled printing device.

The Cartesian coordinate system has a transport direction x, a direction orthogonal thereto in relation to gravity as well as a direction y orthogonal to the transport direction x. The - not shown - pressure window is arranged transversely to the support plate 9 in the y direction. The at least one ink cartridge 11 has a forward bulge 11.1 and a downward ink jet print head 11.2. The ink cartridge 11 is arranged in the Cartesian coordinate system so that, in the printing position, the bulge 11.1 of the ink cartridge 11 is moved forward, i. opposite to the transverse direction y and upwards, i. directed against the force of gravity in the direction of transport x orthogonal direction z.

In the FIG. 5 is a perspective view of the printing device with the proposed transport device, with chassis and with print module shown in the print position. The transport device 20B is an integral part of a postage meter machine and is disposed above a mail piece feed table (not shown). The printing module consists of a printing carriage 24, a contacting and driving unit for the ink cartridges and the ink cartridges themselves, which are each equipped with an inkjet printhead. Two ½ "ink cartridges 11, 12 from Hewlett Packard, for example, offset from each other in the x / y direction, are used, and the print carriage 24 is arranged transversely on two transverse rods 271, 272 and can move in the y direction transversely to the mailpiece transport direction (x-direction) are moved within a box-shaped space, which is formed by a metal chassis. The metal chassis consists of a right side wall 25, which merges into a tab 23 which is angled towards the front by 90 °. The metal chassis consists of a left side wall 26, which merges into a tab 29 which is angled towards the front by 90 °. The right side wall 25 and the left side wall 26 are fixed to a rear wall 28. On the rear wall 28, for example by screws via crossbars 271, 272 a simple embodiment of a bearing plate 22 is fixed, which carries a number of rollers on which the flat belt 2 is stretched.

The flat belt 2 of the mailpiece transport device has a large transverse rigidity and is guided over two outer by the bearing plate 22 partially concealed pulleys 5 and 6, which are respectively arranged at the ends of the bearing plate and molding plates. In this case, the flat belt 2 on the one hand passes under the downwardly facing support surface of the support plate and on the other hand, between the belly of the ink cartridges 11, 12 and the upwardly facing surface of the support plate (not visible) returned. The printing module projects in the printing position partially in the space between the pulleys, with the ink jet heads of the two ink cartridges located outside the transport area - not visible - pressure window. The left side wall 26 has a greater length in the y-direction than the right side wall 25, wherein the angled tab 29 of the left side wall 26 in the x-direction (transport direction) and the angled tab 23 of the right side wall 25 opposite to the x-direction , The angled tab 23 of the right side wall 25 extends to the molding plate 212 zoom and the angled in the x-direction tab 29 of the left side wall 26 extends to the inside of the bearing plate 22 zoom. The molding plates 211, 212 and the bearing plate 22 are spaced apart according to the width of the flat belt 2. The bearing plate 22 has an inwardly smooth base plate 223 with forwardly bent edge strips 222 and ribs 224 for the purpose of reinforcement and production of sufficient torsional rigidity and tensioning means 225, 226, 227 and 228 and a pull rod 221 on the front in order to absorb the tensile forces which act on the bearing plate 22 during tensioning of the flat belt 2 and to adjust or compensate for the distortion or bending of the bearing plate. The molding plates also have an inwardly smooth base plate. The distance between the molding plates 211, 212 and the bearing plate 22 is - in a manner not shown - on the one hand by the rollers and their bearing axes and on the other hand by the between the mold plates 211, 212 and the bearing plate 22 arranged a support plate (hidden) guaranteed. The molding plates 211, 212, the bearing plate 22, the support plate and the rollers 5, 6 (and hidden rollers 7 and 8) are assembled into a roller carrier. The driven conveyor belt forms a recessed from above oval loop, wherein the indentation is formed by (hidden) additional guide rollers 7, 8 in front of and behind the ink cartridges. The conveyor belt is guided in both directions under the belly of the ink cartridges, wherein the pulling strand of the conveyor belt from the center of the transport device in the transport direction is supported by an opposite to the z-direction, ie downwardly facing smooth support surface.

Due to the indentation creates sufficient space and the belly of the ink cartridge can also point forward. The front wall of the mail piece transport device is designed as a one-sided bearing plate 22 for the deflection rollers and has a metallic pull rod 221, by means of which the counter pull force is applied to the belt tensile force of the flat belt 2. The tie rod is in the x direction, i. to the mailpiece transport direction, arranged in parallel. In this arrangement, the ink cartridges can be removed directly upwards, without having to take a previously provided separate position.

The transport device with printing module is used in a microprocessor-controlled printing device, for example in a franking machine, for transporting mail items. A franking machine consists - in a manner not shown - known, inter alia, an electronic part (meters) and the mail piece transport device with an electronic control and a pressure device. The - not shown - from below resiliently pressing against the mailpiece pressure device is below arranged a known feed table. A keyboard and a display unit of the meter are connected to the electronic part in a manner not shown. The electronic control is known on the one hand with an encoder and on the other hand with a motor of the mail piece transport device to the control in - not shown - connected.

The FIG. 6 shows a perspective view of the proposed transport device and a drive device of the transport device of the printing device from the front right top in exploded view. The drive device 20A of the transport device 20B of the printing apparatus consists of a base plate 31 of a metal chassis and gear and drive means arranged thereon. The latter include at least one gear 32 and a motor 33 with a corresponding power transmission means (not shown).
Alternatively, the worm wheel 32 may be replaced by a pulley, toothed belt wheel, or equivalent means.

In the example shown, a distance between the gear and drive means and the transport device is bridged by a shaft 233 on the metal chassis, wherein the distance results from the dimensions of the printing device. For example, an ink printing device (not shown) is used which has a printing carriage for a printing module. Then also a - not shown - drive device of the print carriage is arranged on the metal chassis.

The metal chassis of the drive device 20A of the transport system of the printing system is designed, for example, as a frame consisting of the base plate 31 with a U-shaped 90 ° inwardly angled side walls 25, 26, wherein a right side wall 25 merges into a tab 23, the Front is angled 90 ° inwards and wherein a left side wall 26 merges into a tab 29 which is angled towards the front by 90 ° inwards. The base plate 31, the right side wall 25 and the left side wall 26 are fixed to a rear wall 28. On the rear wall 28 are, for example fastened by screws, two equal length crossbars 271, 272, which are passed through each a hole 230, 290 in the tab 23, 29 to the front. The crossbars 271, 272 serve on the one hand for guiding the method of printing carriage transversely to the transport direction and on the other hand for fixing the roller carrier of the transport device 20B for - not shown - mail pieces or other flat goods to be printed. The word "flat" refers to the dimension of the commodity in the z-direction of a Cartesian coordinate system. The transport direction is the x-direction. The crossbars 271, 272 are transverse to the transport direction, ie, parallel to the y-direction, and the printing apparatus stands on a table or is arranged above the table in the z-direction within a postage meter or other flat-goods processing apparatus.

The roller carrier of the transport device 20B is attached to the crossbars 271, 272 of the frame of the printing device and attached. The mounted on the roller carrier conveyor belt 2 is driven by a drive roller 5, which has an outer toothing at one end. The drive energy is supplied by a drive pinion 232 mounted on a drive shaft 233, which engages with the external teeth as soon as the roller carrier is attached to the transverse rods 271, 272. The drive shaft 233 is rotatably mounted in a first bearing 231 of the tab 23 and in a second bearing 281 of the rear wall 28.

The left side wall 26 has a greater length in the y-direction than the right side wall 25, wherein the angled tab 29 of the left side wall 26 in the x-direction (transport direction) and the angled tab 23 of the right side wall 25 opposite to the x-direction ,

The roller carrier of the transport device 20B consists of a bearing plate and two molding plates, wherein the molding plates 211, 212 and the bearing plate 22 via spacers (partially hidden) corresponding to the width of the conveyor belt 2 are spaced apart.

The angled tab 23 of the right side wall 25 extends to the molding plate 212 zoom and the angled in the x-direction tab 29 of the left side wall 26 extends to the inside of the bearing plate 22nd approach. The molding plate 212 has at the top a first opening 2121 for receiving the drive pinion 232 and an adjacent second opening 2122 for inserting the crossbar 272 of the right tab 23.

The bearing plate 22 is in principle like the simple bearing plate after Fig. 5 constructed and has in the upper region openings 2201 and 2202 for releasably securing the bearing plate 22 to the crossbars 271, 272 by means of screws 22011 and 22021. But it has a more complex structure on the front, as the simplified design variant. Alternatively, the attachment via lock washers, split or quite different, but the attachment of the bearing plate 22 remains releasable.

A downwardly disposed non-visible spacer to the first molding plate 211 and an upper spacer 208 to the second molding plate 212 is formed as a spacer column. The bearing plate 22 has in the lower or upper region openings 2203 and 2208 for attachment of these spacer columns. Preferably, press and shrink connections are provided. The spacer pillars may alternatively have holes with an internal thread or pins with an external thread at their ends for attachment by means - not shown - have screws or nuts. Alternatively, the attachment can also be done completely different form and locks. The ends of the spacer columns are adapted and shaped accordingly.

A spacer 204 to the first molding plate 211 is formed as a spacer column and also serves as a bearing shaft for a rocker 200. The bearing plate 22 has in the upper part of an opening 2204 for attachment of this spacer column. For attachment of the already communicated above facts to the embodiment applies.

The spacers are all connected to one bearing plate, with three spacers concentrically arranged at each of the two ends of the bearing plate. Here, two bearing shafts and a spacer column are provided as spacers in each case.

The bearing plate 22 has in the central region openings 2205 and 2206 for fixing the bearing shafts of the rollers 5 and 6. For the Fixing also applies to the already communicated above facts to the embodiment. The rollers have at their two ends depending on an internally arranged bearing (not visible). Advantageously, needle roller bearings or ball bearings can be used to reduce the rolling resistance.

Between a first shaped part plate 211 and the bearing plate 22, a first deflection roller 8 is arranged next to the driven roller 6 and between a second shaped part plate 212 and the bearing plate 22, a second deflection roller 7 is arranged next to the drive roller 5. As a result, the conveyor belt is guided in the form of a loop such that a sufficiently large space is created between the deflection rollers for the pressure module (not shown) moved into a printing position. The first deflection roller 8 is rotatably mounted on the rocker 200, which is mounted space-saving between the first mold part 211 and the bearing plate 22, because at least the molding 211 has a molded-in cavity in the inner wall 210, which is required for movement of the rocker 200, when the conveyor belt is mounted on the roller carrier 20. The bearing plate 22 carries a number of rollers on which the conveyor belt 2 is stretched. The conveyor belt 2 is formed as a flat belt. The flat belt of the mailpiece transport device has a large transverse rigidity and is guided over two outer by the bearing plate 22 partially hidden input and output rollers 5 and 6, which are respectively arranged at the ends of the bearing plate and molding plates. In this case, the flat belt on the one hand passes under the downwardly facing support surface of a support plate 9 and on the other hand, between the pressure module moved in printing position and the upwardly facing surface of the support plate (not visible) returned.

The bearing plate 22 has in the zx plane a smooth base plate 2200 with forwardly shaped in the z-direction extending frames 2241, 2242, 2243, 2244 and possibly further - not shown - frames 224i and extending in the x-direction ribs 2221, 2222nd , 2223, 2224 and possibly further - not shown - ribs 222j for the purpose of reinforcement and production of sufficient torsional stiffness and also clamping means 225, 227 and clamping and adjusting means 226, 228 and a pull rod 221 on the front to absorb the tensile forces . which act on the bearing plate 22 during tensioning of the transport belt 2 and adjust or compensate for the distortion or bending of the bearing plate. In the example shown, the ribs 2221 and 2224 form in the region of the gap a forwardly bent edge strip with a shaped weak point 229 of the structure with a reduced width of the upper edge strip, starting on the base plate 2200 from the transition to the first rib 2221 up to the transition to the fourth rib 2224 increases the width of the weak point gradually, wherein the fourth rib 2224 forms the upper edge strip in the region of the intermediate space.

In the example shown, there is only one weak point 229 between the second rib 2242 and the third rib 2243. Alternatively, embodiments of the bearing plate having a plurality of ribs are possible, with one or more weak points being incorporated at the same or a different location of the structure of the bearing plate to ensure a bending of the bearing plate 22 during clamping of the conveyor belt 2 in a defined manner.

The bearing plate 22 carries a first pin with the first opening 2201 for mounting the bearing plate on the first crossbar 271, wherein the pin is disposed on the one hand between the third rib 2223 and fourth rib 2224 and on the other hand between the third rib 2243 and fourth rib 2244. The bearing plate 22 carries a second pin with the second opening 2202 for mounting the bearing plate on the second crossbar 272 on the one hand between the third rib 2223 and fourth rib 2224 and on the other hand between the first rib 2241 and second rib 2242 is arranged.

A third opening 2203 for securing the non-visible spacer below is placed in a third pin located between the last and the penultimate frame at the end of the bearing plate 22 and between the first rib 2221 and the second rib 2222. A fourth opening 2204 for attachment of a spacer 204 is placed in a fourth pin located between the last and penultimate frames at the left end of the bearing plate 22 and on the fourth rib 2224 near the penultimate frame is. The first rib 2241 at the right end of the bearing plate 22 carries between the second rib 2222 and third rib 2223 a fifth pin with a fifth opening 2205 for mounting the bearing shaft of the drive roller 5. The ribs and ribs of the bearing plate 22 form nodes at their intersections in FIG whose proximity storage of spacers in openings is particularly strong and stable. Thus, in the example shown, a sixth pin with a sixth opening 2206 for attachment of the bearing shaft of the driven pulley 6 is placed exactly in the node between the last frame at the left end of the bearing plate 22 and the third rib 2223. A seventh opening 2207 for attaching a bearing shaft of the diverting pulley 7 is placed in a seventh pin disposed between the first divider 2241 and second divider 2242 at the right end of the support plate 22 and between the first rib 2221 and second rib 2222. An eighth opening 2208 for attachment of the spacer 208 is placed in an eighth pin located between the first rib 2241 and second rib 2242 at the right end of the bearing plate 22 and between the third rib 2223 and fourth rib 2224 near the second rib.
A ninth opening 2209 for attachment of a locking pin 209 is placed in a ninth pin located between the last and second to last ribs at the left end of the bearing plate 22 and between the third rib 2223 and fourth rib 2224 near the fourth rib 2224.

In the FIG. 7 is a perspective view of the proposed transport device 20B from the top right rear shown in exploded view.
The first molding plate 211 has in the zx plane a smooth base plate 2110 on the inside facing the conveyor belt with a cavity 210 of the base plate for a belt tensioning mechanism. An edge strip 2115 integrally formed on the outside of the base plate in the y-direction has a width B ₂₁₁ and is bent post-upstream into a semicircle. The latter corresponds approximately in its length L half the circumference U of the roller 6, where: L ~ ½ U, where U = Π · D. The diameter D is larger by the factor k than the width B ₂₁₁ , where: D = k · B ₂₁₁ at k = 3 to 10. The width B ₂₁₁ depends on the material parameters and is greater at low strength of the material than at high strength. On the x-shaped box-shaped half of the base plate, pins with holes are arranged outside the circumference, the base plate 2110 being bounded below by a straight edge strip 2111 and upwardly by a straight edge strip 2112, both having the same width B ₂₁₁ have and at its one end in the curved edge strip 2115 pass. The upper straight edge strip 2112 drops in the x direction in a step 2117 onto a projection 2118 of width B ₂₁₁ parallel to the lower edge strip 2111 at the other end of the first molding plate 211. The outer side of the base plate is structured by an outer structure, which in a manner known per se enhances the stability and strength of the molded part plate 211 under load, which occurs in particular when the transport belt 2 is tensioned. The pins with openings are formed on the outside in the y-direction, wherein the pins and the outer structure, the edge strips do not protrude in their width. The pins, outer structure and the width of the edge strips extend parallel to the y-direction, when the molding plate 211 is completed with the bearing plate 22 to the roller carrier 20 is attached to the drive device of the transport device. The openings in the pins are then also parallel to the y-direction. The number of openings of the first and second mold plate 211 and 212 corresponds approximately to the number of openings of the bearing plate 22 for the spacers 203, 204, 206 and 205, 207, 208 and for other components, such as the locking pin 209, etc. and for the - not shown - right crossbar of the drive device of the printing system. The spacers 203, 204, 206 and 205, 207, 208 are fastened to the bearing plate 22 via fastening means 22021, 22041, 22061 and 22051, 22071, 22081. For a plurality of - not shown - openings of the bearing plate 22 is symmetrically in the y direction, a corresponding opening 2113, 2114, 2116 and 2119 in the first molding plate 211 for the spacers 203, 204, 206 and for the locking pin 209 and a corresponding opening 2125, 2127, 2128 in the second molding plate 212 for the spacers 205, 207, 208th

The first molding plate 211 carries a sixth opening 2116 centrally in a pin and the edge strip 2115 which extends around the sixth opening 2116 in a radius, for example, approximately equal to the output roller 6, wherein the sixth opening 2116 for fixing the bearing shaft 206 of the driven pulley 6 is provided. For the spacers 203, 204, 206 fastening means 21131, 21141, 21161 are provided for fixing the first molding plate 211. A in the zx plane on the inside facing the conveyor belt smooth base plate 2120 of the second molding plate 212 carries a total of five openings with molded edge strips 2123, 2126 and 2129. The width B ₂₁₂ extends parallel to the y-direction, when the molding plate 212 with the Bearing plate 22 to the roller carrier 20 is completed attached to the drive device of the transport device. It is envisaged that the first opening 2121 of the second molding plate 212 is formed with a sufficiently large cross section for the drive pinion (not shown) and that the second opening 2122 has a sufficiently large cross section for passing the second transverse rod (not shown). The molded-on edge strip 2123 delimits a fifth opening 2125 and both aforementioned openings 2121 and 2122 downstream, ie in the x-direction and z-direction (upwards) and closes on the one hand with a straight-sided straight edge strip 2126, ie against the x-direction and on the other hand a lower straight edge strip 2129. All edge strips have the same width B ₂₁₂ , which is dimensioned so that a grip protection is provided to the drive pinion.

For the spacers 205, 207, 208, openings 2125, 2127, 2128 are provided in the second molding plate 212 and fastening means 21251, 21271, 21281 for attachment to the second molding plate 212. To mount the roller carrier 20 of the transport device, the spacers 203, 204, 206 and 205, 207, 208 attached to the bearing plate 22 and a support plate 9 inserted between the loop of the conveyor belt 2 and placed on the bearing plate 22.

The support plate 9 has on the conveyor belt 2 side facing a sliding surface, ie on that side of the support plate 9, against which the conveyor belt 2 is pressed over a large area. The sliding surface has a low coefficient of friction in the range 0.1 · 10 ^-6 <μ <0.3 · 10 ^-6 between the sliding surface of the support plate and the running side of the conveyor belt 2. This reduces the friction and thus the necessary drive energy used to move the conveyor belt 2 , Different materials can be used to create the sliding surface of the support plate, for example plastic and / or metallic materials. Alternatively, lubricating films may be applied by gluing and / or sliding layers by polishing.

The conveyor belt 2 has a rough structure on the outer surface (transport side) and has adhesive properties. A very high coefficient of friction in the range 0.9 · 10 ^-6 <μ <1.3 · 10 ^-6 between the transport side and the flat Good is advantageous to transport the letter as possible without slippage, which decides the impression quality influenced.

The drive roller 5, however, has an average coefficient of friction of at least μ = 0.5 × 10 ^-6 on the mantle surface, on which the conveyor belt 2 runs with its running side. In order to transfer the drive power used to the conveyor belt with low slip, rough structures can additionally be applied or adhesive properties can be generated. A roughening of the mantle surface can be done for example by sandblasting, which advantageously prevents slippage of the conveyor belt 2. Also partially or completely applied rubber coatings on the mantle surface are suitable. The sliding friction can thereby be increased up to μ = 0.8 · 10 ^-6 .
The constructive created by the pulleys high wrap of the conveyor belt 2 to the drive roller 5 is greater than 230 ° and thus additionally prevents the slippage of the conveyor belt. Advantageously, the output roller 6 is provided larger in diameter than the drive roller 5 to be able to introduce up to 10 mm thick flat goods easily into the transport device. By the resulting Flatter wedge angle also reduces the drive energy required when drawing in thicker flat goods.

A band tensioning mechanism is designed as a rocker 200. The latter consists of two external angle levers 201 and 202, which are spaced from each other via a center plate 2001 and at one end of the lever arm bearing a bearing shaft 2008 with a guide roller 8. The respective other lever arm of the angle lever 201, 202 is centered at approximately 90 ° and serves for locking together with the locking pin 209. The angle lever 201, 202 carry in the Abwinkelbereich one opening 2011, 2021 for storage on the formed as a bearing shaft spacer 204th ,

During assembly, the rollers 5, 6, 7 and the rocker 200 are plugged onto the spacers 205, 206, 207 and 208 formed as bearing shafts, the conveyor belt 2 is placed on the rollers and then the shaped part plates 211 and 212 with the smooth belt facing the conveyor belt Laid inside and fastened. The rollers 5, 6 and 7 have a running surface with the width B _L > B _B (width of the conveyor belt) and each have in the middle a needle bearing on both sides. Only the needle bearings 51, 61 and 71 on the back are in the FIG. 7 visible, noticeable. The drive roller 5 additionally has an external toothing 53 which projects into an opening (not visible) of the base plate 2120 of the second shaped part plate 212. The conveyor belt 2 wraps around the arranged on the ends of the roller carrier rollers 5, 6 due to the impressing from above the oval loop pulleys 7, 8. The conveyor belt is guided in both directions under the - not shown - pressure means along, wherein the pulling Run of the conveyor belt from the center of the transport device in the transport direction by the downwardly facing smooth support plate 9 is supported.
The rocker 200 is rotatably mounted on the bearing shaft 204 after assembly and disposed between the first molding plate 211 and the bearing plate 22. The bearing plate 22 and the first molding plate 211 both have a cavity 220 and 210 formed on the smooth surface of the base plates 2200 and 2110 facing the conveyor belt. The cavities are required to move the rocker 200 when the conveyor belt is mounted on the roller carrier 20. The roller carrier 20 carries a number of rollers on which the conveyor belt 2 is tensioned by means of the rocker 200, wherein the rocker arm 200 is fixed by means of locking pin 209. The first molding plate 211 has a hole 2119 and the bearing plate 22 has a hole 2209 for passing the locking pin 209. The first and second molding plate 211, 212 may each have a rim of lesser width than the width B _{22 of} the edge of the bearing plate 22 their ends. The bearing plate has first and second holes 2201 and 2202 for attaching the transport device to the associated drive device. In the area between the two holes, the bending strength of the bearing plate 22 is defined defined by a constructed strengthening and / or weakening of the structure. An increased width of the edge strip 2224 results in a constructed strengthening, and a reduced width of the edge strip in the region of the cavity 229 results in a designed weakening of the structure of the bearing plate 22.

The bearing plate 22 has at least one inwardly smooth base plate 2200 with front edge strips bent to reinforce and produce sufficient torsional rigidity, tensioning means 225, (227 hidden) and clamping and adjusting means 226, 228 and a pull rod 221 on the front to the To absorb tensile forces acting on the bearing plate 22 during tensioning of the transport belt 2 and to set or compensate for the distortion or bending of the bearing plate defined. It is advantageous if the drawbar 221 is designed as a hexagon screw. The clamping and adjusting means 226 is as a screw head and the clamping and adjusting means 228 is formed as a nut.

A defined deflection of the bearing plate 22 can alternatively be achieved by a specific order and arrangement of several reinforcements and weakenings of the structure of the bearing plate 22. As a result, a curve of the deflection of the bearing plate 22 can be achieved according to a certain mathematical function under load. For example, a deflection of the bearing plate 22 with a logarithmic or potential course as well as an absolutely rectilinear uniform course.

In the FIG. 8 is a perspective view of the roller carrier of the transport device from the front right above shown. The roller carrier 20 consists of the bearing plate 22, the first molding plate 211 and the second molding plate 212 and the spacers 203, 204, 206 and 205, 207, 208. The base plate 2110 of the first molding plate 211 has on the conveyor belt inside facing a cylindrical bag 2100, which is arranged in a circle around the spacer 206 and to the left of the cavity 210 for the belt tensioning mechanism. Between the edge strips 2112 and 2115, a top-accessible compartment 214 for an electronic module is incorporated. In the area of the cavity 210 near the compartment 214, a hole 2119 for the locking pin is incorporated in the base plate 2110. The cavity 210 is open to the edge strip 2117 down to the projection 2118, which is arranged parallel to the lower edge strip 2111.

The base plate 2120 of the second molding plate 212 has on the inner side facing the conveyor belt a cylindrical pocket 2124 which is arranged in a circle around the spacer 205 and to the left of the first opening 2121 so close that the opening passes into the pocket, while the first 2121 is spaced from the second opening 2122. The pocket 2124 is bounded below by the edge strip 2129 and the first 2121 and the pocket 2124 are bounded to the right and up by the edge strip 2123. The base plate 2120 is bounded to the left by the edge strip 2126.

The bearing plate 22 has a post formed upstream post web 224 having a width B ₂₂₄ that merges seamlessly downward (to the tabletop) with the bottom marginal strip 2221, with the edge strip 2221 bounding the base plate 2200 downwardly and formed forwardly with a width, which rises in the x-direction to the middle. On the other hand, the edge strip 2226, which is up to the middle of the bearing plate, is connected to the support web 224 at the left end of the bearing plate 22 22, the base plate 2200 is limited upward and is also formed forward with a width that increases in the x direction to the middle. An edge strip 2224 arranged in the middle section of the bearing plate 22, which bounds the base plate 2200 upwards and is formed forward with a greater width B ₂₂₂ > B ₂₂₄ , merges seamlessly and in a ramp shape into the upper edge strip 2226. The outer edge strips 2221 and 2224 may also be ribs of a forwardly formed structure on the base plate 2200, with the ribs extending in the x direction. Strengthening of the structure is achieved by integrally molded ribs 2221, 2222, 2223 and 2224 and ribs 2241, 2242, 2243, 2244 and 2245 forming a cell structure with the ribs extending in the y direction.

Alternatively, a honeycomb structure is conceivable which has sidewalls which are not parallel to the axes of the Cartesian coordinate system, i. which take a different course than described above.

In the edge strip 2224, which limits the base plate 2200 in the middle region of the bearing plate 22 upwards, a weakening of the structure is incorporated. The weakening is achieved here by a compartment-shaped cavity 229 on the inside of the base plate 2200, which reduces the width of the upper marginal strip and that of the ribs between the second 2242 and third rib 2243 to the width B ₂₂₉ .

Alternatively, weakening of the structure is conceivable in another way, such as reducing the wall thickness of the cell or honeycomb walls in accordance with the material parameters (e.g., Young's modulus).

On the one hand, the edge strip 2221, which delimits the base plate 2200 downwards, and the edge strip 2224, which delimits the base plate 2200 in the middle region of the bearing plate 22 in a post-edge edge strip 2225. On the other hand, the width of the forwardly formed edge strips 2221 and 2224 between the second and first ribs in the x direction from the width B ₂₂₂ to the width B _{22 can be} reduced.

On the base plate 2200, pins connected to the cell or honeycomb structure are provided with openings 2201, 2202, Bearings of the drive and driven rollers are clamping devices 225 and 227 molded. The pull rod 221 is shown cut on one side to illustrate the position of the opening 2203 and its arrangement in a pin, whereas the position of the opening 2207 and its arrangement is concealed in a pin by the there drawn uncut drawbar 221.

The width of the second rib is increased at its two ends and passes into the clamping means 225 and 227, which project beyond the structure to the front and each having an opening for a plug-in in the x-direction drawbar 221 on the front of the bearing plate 22. By means of clamping and adjusting means 226, 228, the drawbar 221 is tensioned on the front in order to absorb the tensile forces acting on the bearing plate 22 during tensioning of the conveyor belt 2. In this way, it is possible to adjust the distortion or bending of the bearing plate defined or compensate.

Although the bearing plate 22 has a honeycomb or cell structure on the front, which contributes to material savings and weight savings, but it is still not flexurally and Torsionsarm designed. On the contrary, it allows a defined deflection.

The FIG. 9a shows a plan view of the concave curved in the y direction roller carrier of the transport device. Such a (exaggerated) deflection of the roller carrier 20 is formed with a corresponding load by a force exerted by the pull rod 221 mechanical tension, which is transmitted via the clamping means 225 and 227 on the two ends of the bearing plate 22. About the tensioning and adjusting means 226, 228, the tension can be adjusted. The first molding plate 211 and the second molding plate 221 are fixed to the bearing plate 22 via the spacers 203, 204, 206 and 205, 207, 208. This can be done by screws or press-fit. The FIG. 9c shows a schematic representation of the force effect on the bearing plate 22. The first tensile stress F1, which is exerted by the mechanical tension in a mounted conveyor belt on the spacers on the bearing plate 22, counteracts an adjustable second tensile force F2, by a on the outside of the Bearing plate mounted tie rod is applied.

The FIG. 9b shows a plan view of the convexly curved roller carrier of the transport device. Such a (exaggerated) deflection of the roller carrier 20 is formed with a corresponding load on the rollers (not shown) by a mechanical tension of the assembled conveyor belt (not shown). As a conveyor belt here is a flat belt used.
The unilaterally acting first tensioning force F1 and second tensioning tensioning force F2 cause a deliberate deflection of the bearing plate 22 FIG. 9a or 9b , depending on the belt tension or tension by the tie rod 221. In concave curved roller carrier after Fig. 9a are the left and right fixed spacers, which are designed as bearing shafts for the pulleys, no longer perpendicular and parallel to each other, they tilt inwards. However, those spacers, which are each connected to the same molding, continue to be parallel to each other axis. The flat belt does not find a stable track as long as the belt tensile forces can not be evenly distributed across the belt width. That is, a mounted conveyor belt runs due to the non-axially parallel groups of spacers at the two ends of the bearing plate 22 intentionally to the molding plates. By a Gegenzug-device with a threaded tie rod, which is arranged externally on the opposite side of the bearing plate side, can be constructed by turning the clamping and adjusting means 226 of the Gewindzugstange 221 a counterforce to the belt tension. As a result, the deflection of the bearing plate goes back and can also go in the opposite direction of deflection. This now makes it possible, when the belt is driven, the intended belt track position to adjust. The advantages are that no additional adjustable belt track elements must be used and all those bearing shafts simultaneously act as belt track elements on which the rollers run. Likewise, the fixed bearing shafts need not be arranged costly exactly to each other. And the bearing plate does not need to be redesigned at a higher belt tension, because the retraction device compensates for the deflection. This allows a cost-effective and simple construction.
For example, the bearing plate has firmly pressed in each case three fixed spacers designed as bearing shafts on the left and right end of the bearing plate. These are used to attach the first and second molding plate on the left and right end of the bearing plate frontally (with a screw). This creates a three-point attachment that prevent rotation of the molding plates to the bearing plate.
The pulleys are preferably designed crowned or cylindrical and each provided with a chamfer at the edges. They stabilize the track of the conveyor belt in addition to transversely introduced lateral forces and disturbances, which has a direct positive effect on the print quality. Also, the conveyor belt runs faster back to its preset track and facilitates the adjustment and adjustment.
The flat belt with fabric insert has a given belt length and tolerance, also a given tensile force for 1% belt elongation, this results in a known belt length.
This specifies the center distances of the pulleys on the bearing plate exactly. One of the pulleys is mounted in a rocker. The rocker is pivoted away. When the belt is laid, the rocker is unlocked from its lock and swung away, also are the molding plates, not yet mounted, that easy, the belt can be used. The molded panels are mounted, then the rocker is pivoted back into its lock and automatically tensions the belt to its optimum belt tension. The locking takes place via a plug-in axle. To change the belt, the transport unit is removed from the machine and removed the thru axle for locking the belt tensioner. Subsequently, the molding plates are removed. The belt tensioner swings away and the belt can now be easily changed. In the reverse order, the transport unit is assembled again.
After installation in the machine, the drive is activated and the belt track position adjusted by adjusting the counter-pulling device. This can be done by a service technician on site at the customer. Advantageously, the clamping and adjusting means of the pull rod are designed as a screw or nut, with which the tracking of the conveyor belt in a range of 0 to ± 10 mm can be adjusted freely.

The invention is not limited to the present embodiment per se. Rather, a number of devices within the scope of the claims are conceivable, which are used and which are based on the same basic idea of the invention, from the appended claims.

Claims (23)

1. A transport device for flat goods to be printed of a microprocessor-controlled print device having a roller-borne driven transport belt (2) that extends in a width in the y-direction of a Cartesian coordinate system and that transports flat goods to be printed on in the margin area in the transport direction x past at least one print head of a print module during printing, the flat goods being pressed against the transport belt (2) contrary to the force of gravity in a support area, the print device having, for the at least one print head (11.2), a print window (3) that is arranged on the margin of the transport belt (2) in a housing part of the print device, the print device being arranged above the print window (3) in the z-direction of the Cartesian coordinate system, and the at least one print head (11.2) producing a print image opposite to the z-direction in direction of the force of gravity during the printing process, wherein

   - the support area extends on both sides of a line (4) that runs centrally through the print window (3) at right angles to the transport direction x, in the y-direction of the Cartesian coordinate system, the transport belt (2) supporting itself against a support plate (9) that is arranged above the supporting area of a roller carrier (20) between a moulded plate (211) and a bearing plate (22), the supporting area of the support plate (9) being larger than the area of the print window;

   - the roller carrier (20) comprises moulded plates (211, 212), the bearing plate (22), the support plate (9) and a number of rollers (5, 6, 7 and 8) for guiding the transport belt (2) along a centrally indented oval curve, the transport belt (2) being tightly tensioned in the indented section by means of a tensioning roller (8) and the indented section being designed at least in part for receiving the bulge (11.1) of at least one ink cartridge (11) of the print module; and

   - the bearing plate (22) has a surface structure according to desired bending characteristics and bears, on both ends on an inner side, a number of spacers for fixing the moulded plates (211, 212) and, on an outer side, tensioning means (225, 227) for pre-tensioning the bearing plate (22).
2. A transport device according to Claim 1, characterized in that the transport belt (2) is a flat belt and has a width (W3) in the y-direction of the Cartesian coordinate system that is broader than the width (b) of a print window (3).
3. A transport device according to Claim 1, characterized in that the flat belt has a high transverse rigidity and is guided via two outer return rollers (5 and 6) which are arranged at the ends of the bearing plate (22) and of the moulded plates (211, 212), respectively, the flat belt (2) passing through below the downward-pointing supporting surface of the support plate (9) on the one hand and being guided back between a part of the print module and the upward-pointing surface of the support plate (9) on the other hand.
4. A transport device according to Claim 1, characterized in that a print module comprises a printer carriage (24), a contacting and driver unit for the ink cartridges and the ink cartridges (11, 12) as such each of which is equipped with an ink-jet print head; that the printer carriage (24) is arranged in a transversally movable manner on transverse bars (271, 272) and can be moved in y-direction at right angles to the transport direction of postal items (x-direction) into a box-shaped compartment that is formed by a metal chassis the right side wall (25) of which passes, at the front, into a flap (23) that is bent by 90° and comes up to the moulded plate (212) and the left side wall (26) of which passes, at the front, into a flap (29) that is bent by 90° in the x-direction and comes up to the inner side of the bearing plate (22) so that the print module, in printing position, in part projects into the space between the return rollers (5, 7, 6, 8) and the ink-jet print heads of the two ink cartridges (11, 12) are located in the print window that is arranged outside the transport area.
5. A transport device according to Claims 1 and 4, characterized in that at least one ink cartridge (11) is used in a microprocessor-controlled print device with a print window through which the at least one ink-jet print head (11.2) of the at least one ink cartridge (11) sprays ink droplets onto the surface to be printed of a postal item (10) or flat item that, lying on the side not to be printed, is transported by means of the flat belt.
6. A transport device according to Claims 1, 4 and 5, characterized in that, in a Cartesian coordinate system, the x-direction is the transport direction of the postal item (10) or flat item that is transported lying on the side not to be printed; that the y-direction points backward to the rear side and the z-direction points upward to the upper side of the microprocessor-controlled print device; that the print window is arranged at right angles to the support plate (9) in y-direction: and that the at least one ink cartridge (11) has a bulging (11.1) pointing to the front and an ink-jet print head (11.2) pointing downward.
7. A transport device according to Claims 1 and 4 to 5, characterized in that the microprocessor-controlled print device is a franking machine.
8. A transport device according to Claim 1, characterized in that, on the one hand, a first number of spacers (203, 204, 206) is provided between one end of the bearing plate (22) of the roller carrier (20) and a first moulded plate (211), that, on the other hand, a second number of spacers (205, 207, 208) is provided between another end of the bearing plate (22) and a second moulded plate (212), that one tensioning means (225) and (227) each is fixed at the ends of the bearing plate (22) of the roller carrier (20) and is designed for transmission of force from a tie rod (221), wherein, for the purpose of a defined bending of the roller carrier (20) with a respective loading of the bearing plate (22), a mechanical tension is transmitted via the tensioning means (225) and (227) to the two ends of the bearing plate (22); and that there are provided tensioning and setting means (226, 228) of the tie rod (221) by means of which the tension can be set.
9. A transport device according to Claims 1 and 8, characterized in that all of the spacers (203, 204, 206) and (205, 207, 208) are of the same design.
10. A transport device according to Claims 1, 8 and 9, characterized in that the spacers (203, 204, 206) and (205, 207, 208) are equally designed as bearing shafts and that, for track alignment, the spacers (203, 204, 206) and (205, 207, 208), respectively, are axially parallel to one another at the same end of the roller carrier (20).
11. A transport device according to Claims 1 and 8 to 10, characterized in that the spacer (204) is designed as bearing shaft for a rocker (200) of a tensioning mechanism of a transport belt (2) and that the spacers (205, 206, 207) are designed as bearing shafts for rollers (5, 6 and 7) of the transport belt (2).
12. A transport device according to Claims 1 and 8 to 11, characterized in that the rocker (200) comprises two angular levers (201 and 202) located at the outside that are spaced from one another by a middle plate (2001) and carry a bearing shaft (2008) with a return roller (8) on the one end of the lever arm, wherein the respective other lever arm of the angular levers (201, 202) is centrally angled by 90° and serves he purpose of locking together with a locking pin (209), the angular levers (201, 202) having, in the angle area, an opening (2011, 2021) each for being borne on the spacer (204) designed as a bearing shaft.
13. A transport device according to Claim 1, characterized in that the bearing plate (22) has a first (2201) and a second hole (2202) for fixing the transport device (20B) to the associated drive device (20A), wherein, in the region between said two holes, the bending strength of the bearing plate (22) is defined by a designed strengthening or weakening of the structure.
14. A transport device according to Claims 1 and 13, characterized in that the regions of strengthening and/or weakening of the structure are adjacent to one another.
15. A transport device according to Claims 1, 13 and 14, characterized by a certain sequence and arrangement of several strengthened and weakened parts of the structure of the bearing plate (22) producing a defined bending of the bearing plate (22) so that, under stress, there is achieved a course of bending of the bearing plate (22) according to a certain mathematical function.
16. A transport device according to Claims 1, 13 to 15, characterized in that there is enabled a bending of the bearing plate (22) with a logarithmic or potential course.
17. A transport device according to Claims 1, 13 to 15, characterized in that there is enabled a bending of the bearing plate (22) with an absolutely uniform linear course.
18. A transport device according to Claims 1, 13 to 15, characterized in that the bearing plate (22) has at least one base plate (2200) plain on the inside with edge strips bent to the front for reinforcement and for producing a sufficient torsional rigidity, tensioning means (225, 227) as well as a tie rod (221) and tensioning and setting means (226, 228) of the tie rod (221) on the front side, wherein, by an increased width of at least one edge strip (2224), there is achieved a designed strengthening and, by a reduced width of the edge strip in the region of the cavity (229), there is achieved a designed weakening of the structure of the bearing plate (22).
19. A transport device according to Claims 1, 13 to 15 and 18, characterized in that the tie rod (221) has the form of a hexagonal bolt.
20. A transport device according to Claims 1, 13 to 15 and 18, characterized in that the tensioning and setting means (226, 228) of the tie rod (221) are designed as screw or nut by means of which the track of the transport belt can be freely adjusted within a range of 0 to ±10 mm.
21. A transport device according to Claims 1, 13 to 15, characterized in that a weakening of the structure of the bearing plate (22) is designed by a reduction of the wall thickness of the cell or honeycomb walls in coordination with the material parameters.
22. A transport device according to Claims 8 to 10, characterized in that, at each of the ends of the bearing plate (22), one of the two moulded plates rests on spacers on three points each, whereby a stable and low-torsion bearing of the moulded plates is achieved by the spacers at both ends.
23. A transport device according to Claims 8 to 10, characterized in that, for each of the two moulded plates (211, 212), there is provided a three-point fixing at both ends of the bearing plate (22).

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