EP2072267B1 - Transport device for flat goods that are to be printed - Google Patents

Abstract

The transport device (1) has a printing module. The transport device is arranged firmly in the printing device opposite to the hardproof device. Two guide rollers (5,6) and a support plate (9) are provided for the transport band (2), in order to form the transport area. The printing module projects partially into the intermediate space between the guide rollers. The printing module has an ink cartridge (11,12) whose ink jet printing head is placed outside the transport area.

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.

From the patent US 6,550,994 B2 For example, a postage meter machine with a mail item transport device is known with which the letters are transported through the postage meter machine by means of an overhead conveyor belt and a plurality of spring-mounted levers arranged below. The same goes out US 5,813,326 . US 6,776,089 B1 and US 6,585,433 B2 out. The conveyor belt is mounted in a loop on rollers and does not allow the pressure module or a 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 for printing franking strips is provided, 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 printhead is arranged to be stationary behind a guide plate in a recess for printing. 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 ) an embodiment for a printing device of an ink-jet franking machine JetMail ^® has been proposed by the applicant Francotyp-Postalia AG & Co., at a non-horizontal approximately vertical letter transport performs a franking pressure by means of an ink jet printhead, which is arranged behind a guide plate in a recess stationary. 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, packet, 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 changed in principle by digital printing in principle in all areas, but the pressure is of lower quality the higher the transport speed is selected. 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 ink-jet print head 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.

From the EP 1 079 975 B1 An apparatus for character printing on a predetermined place on one side of a flat recording medium and a correspondingly equipped franking machine are known. A transport belt is arranged on the one hand on the inkjet printhead side and on the other hand forms a non-suspended support means for the print side of a flat recording medium (object, mail, envelope). A counter-pressure device supports the flat object from below, in which a belt rolls around at least two other rollers, at least one of which is not suspended.

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 Δy offset of the dots in the printed image, especially in very large mailpieces. The structure also causes high manufacturing costs.

EP 881 599 A2 relates to an ink-jet printing device with a conveyor belt running around two rollers.

In the market segment of franking machines with small to medium Mailgutdurchsatz a compact transport device for mail pieces with the lowest possible production costs is required.

The invention has for its object to develop a transport device of 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-direction and y-direction should be low. On the one hand postcards and on the other hand C4 and B4 letters with a mail piece thickness up to 10 mm are to be processed.

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

By a transverse movement of a printing module transversely to the mail item transport direction by means of transverse movement means, a printing position is achieved. When printing by an ink jet printing method, the printing module is held in the printing position and a transport device is arranged to horizontally transport flat goods or a mail piece past the print head. The transport device is stationarily arranged in the printing device with respect to a pressure device which presses the mail piece to the conveyor belt.

The conveyor belt acts in the transport area with a predetermined stiction on a part of the surface of the mail piece, which is not printed, but is located near the area to be printed.

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 on the edge 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 located 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, stretched. The conveyor belt is supported on a support plate, which is arranged above the transport region 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 printing device is arranged in a box-shaped chassis. The box-shaped construction ensures a high stability with a very simple structure. By enlarging the deflection rollers of the transport device, the pressure module can now protrude into the area between the rollers. Thus, and due to the use of a flat belt as a conveyor belt, the guidance during transport of the mailpieces is improved and the printing offset in the x-direction and y-direction is less than 100 microns in both directions. By projecting the printing module or parts thereof and omitting a second printing path, the extension of the chassis and housing in the y-direction, i. reduced transversely to the mailpiece transport direction.

The transport device for flat goods to be printed has a printing module in the printing position, from which the printing module can be moved in a conventional manner in a cleaning and sealing position by transverse movement means known per se transversely to the mailpiece transport direction. The cleaning and sealing position can advantageously be arranged closer to the conveyor belt. This also reduced the size of the chassis and housing across the mailpiece transport direction.

The conveyor belt is preferably a driven wide tensioned flat belt. The latter is guided by means of deflection rollers both over the printing module and under the printing module along, while the printing module is in a printing position. In the printing position, the printing module protrudes at least partially into the intermediate space between the two deflection rollers, but the heads of the two ink cartridges continue to be outside the transport area.

Figur 1,

Perspektivische Ansicht einer Transportvorrichtung für flache Güter mit Druckmodul in der Druckposition,

Figur 2,

Perspektivische Ansicht der Transportvorrichtung in gesprengter Darstellung.

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,

Perspective view of a transport device for flat goods with printing module in the printing position,

FIG. 2,

Perspective view of the transport device in an exploded view.

In the FIG. 1 Figure 3 is a perspective view of a flat goods transport device with a print module in a printing position. The transport device 1 is an essential part of a franking machine and is arranged above a feed table 13. A - not shown - from below resiliently pressing device is arranged below the feed table and acts through an opening 130 through the feed through in the z-direction.

A postage meter is known u.a. from a - not shown - electronic part (meters) and the mail piece transport device with a - not shown - electronic control. A keyboard and a display unit of the meter are connected to the electronic part, not shown. The electronic controller is electrically connected to a drive 19 of the mail piece transport device for driving them. To drive, for example, an electric motor with gear is used. The transport device 1 has a conveyor belt 2, which is designed as a flat belt.

The flat belt operates in the transport area with a predetermined stiction on a part of the surface of the flat goods or mailpieces, which is not printed, but is close to the printing area. The flat belt of the mailpiece transport device has a large transverse rigidity and is guided over two pulleys 5 and 6. In this case, the flat belt on the one hand passes under the pressure module and is on the other hand returned via the printing module. The printing module is known to consist of a print carriage 24, a - not shown - contacting and control electronics on the back of the print carriage 24, and at least one print head, for example, an ink cartridge with integrated inkjet printhead. The print carriage 24 contributes in the example shown Fig. 1 preferably two ink cartridges 11, 12, which are offset from one another in the x and y directions. Alternatively, several ink cartridges are possible. The print carriage 24 each has an opening 2410, 2420 for inserting the ink cartridges 11, 12, which is bounded laterally by a right and left side plate 244 and 243 and the bottom side by a carrier molding and back by a contact field of contacting and control electronics. The carrier molding consists of two halves, wherein a first half 241 is provided with a first opening 2410 for insertion of the first ink cartridge 11 and a second half 242 with a second opening 2420 for insertion of the second ink cartridge 12 and offset in the x direction to the first half , The first carrier molding half 241 is offset in the y-direction to the second half. Each opening is closed at the top by a closing lever 247, 248 per cartridge. The printing module protrudes in the printing position in the space between the pulleys 5 and 6, wherein the ink jet printheads of the two ink cartridges 11, 12 are located outside the transport area and arranged above a - not shown - pressure window against the direction of gravity in the z direction of a Cartesian coordinate system are. The bellies 11.1, 12.1 of the two ink cartridges 11, 12 are located within the space between the guide rollers 5 and 6 above a support plate. 9

In the FIG. 2 a perspective view of the transport device is shown in exploded view. It is envisaged that the conveyor belt 2 is supported on the support plate, which is arranged above the transport region between a molding plate 21 and a bearing plate 22 of a roller carrier 20B. The support surface of the support plate is here greater than the area of a (non-visible) printing window, which is opposite to the at least one ink jet print head. The pressure window is arranged adjacent to the support plate in a table top of the feed table 13 in the y-direction offset from the opening 130, through which a resiliently pressing from below pressure device (not shown) protrudes, which is arranged below the feed table. It is further contemplated that the print carriage 24 of the printing module is adapted to slide on two slide bars 271, 272, which are fixed on the rear side to a rear wall 25 of a box-shaped chassis 20A and the front side to a bearing plate 22 of a roller carrier 20B for the pulleys the roller carrier 20B with the deflection rollers 5 and 6 and with the conveyor belt 2 is a removable from the chassis 20A and replaceable part of the transport device 1. On the roller carrier 20B, the drive 19, for example, an electric motor with gear, fixed and acts drivingly directly on the shaft of the guide roller 5 a.

Alternatively, the driver 19 may be attached to the box-shaped chassis 20A (not shown). The shaft of the drive 19 and the shaft of the guide roller 5 are then coupled to each other via coupling means.

Claims (4)

1. A printing device and transport device for flat items to be printed on, the printing device having a print module, the transport device (1) being arranged on a fixed position in the printing device opposite a pressure device that presses the flat item against the transport belt (2) that acts, in the transport area, with a predefined friction on a portion of the surface of the flat item that is not printed on, but is located close to the area to be printed on, characterized in that there are provided two guide rollers (5, 6) and a support plate (9) for the transport belt (2) to form the transport area, that the guide rollers are enlarged to such an extent that the print module extends at least in part into the space between the two guide rollers, wherein the print module has at least one ink cartridge (11, 12) the ink-jet print head of which, however, continues to be located outside the transport area.
2. A device according to Claim 1, characterized in that the transport belt (2) is a driven broad tensioned flat belt that is guided by means of guide rollers above the print module as well as below the print module while the print module is in a printing position.
3. A device according to Claims 1 to 2, characterized in that the transport belt (2) bears against the support plate that is arranged above the transport area between a formed plate and a bearing plate of a roller carrier, wherein the support surface of the support plate is larger than the surface of the print window that is adjacent to the support plate and opposite which there is arranged at least one ink-jet print head of the print module.
4. A device according to Claims 1 to 3, characterized in that a print carriage (24) of the print module is adequately equipped for sliding on two slide bars (271, 272) fixed, on their rear side, on a rear wall of a box-shaped chassis (20A) and, on their front side, on a bearing plate of a roller carrier (20B) for the guide rollers, wherein the roller carrier (20B) with the guide rollers (5 and 6) and with the transport belt (2) forms a component of the transport device (1) that is removable from the chassis (20A) and exchangeable.

Images