DE19929316A1 - Ink jet printer for producing photographic prints, has edge detection sensor, and devices for applying digital masks to printed and coated images to prevent printing and coating beyond paper edges - Google Patents

Abstract

The printer has at least one paper supply (12), a sheet transport mechanism with three transport belts (30-32), a rear side printer (26), a color ink jet print head (36), a paper edge detection image sensor (46), an arrangement (54) for applying a digital mask to a printed image to prevent printing onto a vacuum belt, a paper drier (48), a coating station (1000), a further edge sensor (1006), and a further arrangement (54) for applying a digital mask to prevent coating on a guide plate.

Description

The invention relates to an ink jet printer for the production of photos prints, especially on an inkjet printer for printing digital photos graphic images.

Digital photographic images offer significant advantages over conventional ones photographic images insofar as they are using digital computer and data communication nication technologies manipulated, stored, retrieved and transmitted can be. Digital photographic images can either be scanned on conventional photographic film of recorded photographic images or directly are generated by digital cameras that work with solid-state image sensors. Today, paper prints of digital photographic color images are produced using thermo printers, electrographic printers, scanners for exposing conventional silver halide photo papers and inkjet printers.

Most amateur photos nowadays are made using optical Printer and photographic paper manufactured. However, it has been found that in amateur photography making prints of the benefits of digital Image processing would benefit because the digital images are in terms of a verbes correct correction of color balance and exposure can be processed digitally and you can add text or special effects to them through digital manipulation or can combine them with other images. In doing so, they are based on silver halide film scanned images to generate digital color images, the digital Color images processed to correct the color balance and exposure, and then The images are printed using a digital color printer. The only ones  digital printers currently available on the market for producing photo prints genes in amateur photography all work with a scanning light beam with which conventional silver halide photo paper is exposed. Developing the Exposed photographic paper is still used in these digital printers on the way of chemical wet development. Handling and disposal of the However, photographic processing chemicals are expensive.

There is therefore a need for a digital printer for making photos deduce the ver with the chemical wet development of photographic paper avoids associated problems and costs.

Among the competing technologies, i. H. Thermal printing, electrography and tin is the use of thermal printing due to the printing speed and the material costs, the electrography due to the equipment costs and complexity limited. As a result, inkjet printing technology is the best solution represents an improvement over the silver halide pressure at the digita len production of photo prints in amateur photography.

The use of inkjet printers for the production of paper prints from digital photographic images are known. Lower resolution images will appear on Desktop inkjet color printers with a resolution in the range of 300 to 1200 dpi manufactured. Graphic inks are used to produce large format color images jet printer on; see for example the published European patent application EP 0 710 561 A2 and the published PCT application WO 97/28003. If it also seems likely that the high-resolution color ink jet printing will become the preferred technique for making photo prints the use of the currently available inkjet printers because of their throughput speed very limited. There is therefore a need for an ink jet Printer for the production of photo prints with high resolution and high throughput. Another problem with images printed with inkjet printers is that Images against solvents, for example water, are very sensitive and tepid can grease or smear if inadvertently exposed to moisture become. There is therefore a need for an improved inkjet printer Production of photo prints with high resolution and high throughput.  

An ink jet printer for making photo prints includes at least one Paper supply to hold a supply of printing paper and a paper sheet feed dereinrichtung, the sheets of printing paper from the at least one paper supply picks up and transported through the printer. Between the at least one Paper supply and a first conveyor belt of the paper belt conveyor is one Rear side printer arranged for printing on the paper back side. One over the arranged first conveyor belt, extending over the entire printing width Color inkjet printhead is used to print an image on a sheet of paper. On Image sensor placed in front of the inkjet printhead detects the edges of the bottom sheet of paper transported through the printhead, and one with the image sensor connected control electronics generates a digi representing the paper area tal mask and applies this to the currently printed digital image in order to avoid the one that is printed on the first vacuum tape over the edge. After this the first conveyor belt, a second conveyor belt is arranged, which is the printed sheet picks up from the first conveyor belt and transports it further through the printer. about a dryer is arranged on the second conveyor belt. The paper dryer contains one Source for generating an air stream to dry the paper chen picture. At the end of the second conveyor belt there is a coating station for Coating the printed paper surfaces arranged. Another image sensor detects the position of the paper edges to create a digital mask that the Position of the sheet of paper reproduces, and to put the digital mask on to coating digital image, whereby a beyond the edges Coating on the tape is avoided. Downstream of the coating station is a third conveyor belt for drying the coated sheet and transporting it away remove the sheet from the printer.

The inkjet printer according to the invention offers the following advantages: An eventu Shrinking of the printing paper in the drying section has no influence on the Pressure range. There is no waste at the cutting station. The maintenance of the Printer is compared to a paper roll printer, where the paper is only after printing is simplified. It can be flawless Deductions are made. The printing speed meets the needs commercial photo laboratories, and the printed image can be effectively through Applying a top layer to be protected.

The invention is based on an Ausfüh shown in the drawing example explained in more detail.

Show it:

Figure 1 is a schematic representation of the ink jet printer according to the invention for producing photographic prints.

Fig. 2 is a schematic illustration of an alternative embodiment of the invention;

Fig. 3 is a schematic representation of a further alternative embodiment of the invention;

Fig. 4 is a schematic representation of the paper cutter used in the ink jet printer according to the invention;

Fig. 5 is a schematic representation of the image sensor used in the ink jet printer according to the invention;

Fig. 6 is a schematic representation of the arrangement of an ink jet printer according to the invention;

Fig. 7 is a perspective view of a buffer section in a printer with the arrangement shown in Fig. 6;

Fig. 8 is a belt cleaning device used in connection with the invention a detail cross section of the nozzle;

FIG. 9a is an air knife used in the inventive paper dryer is a perspective view;

FIG. 9b is a coating dryer used in the invention is a perspective view;

FIG. 10 is a schematic perspective view of the tape transport in the region of the pressure head of the invention; and

Fig. 11 is a perspective view of the processing station Beschich used in the invention.

In Fig. 1, an ink jet printer according to the invention, generally designated 10, for printing photographic images has a paper supply roll 12 for feeding a paper web 14 of photographic inkjet printing paper. The photographic ink jet printing paper consists for example of 10 cm wide white paper with a weight of 200 to 300 g / m ² , which is specially surface-treated in a known manner for the absorption of ink by the ink jet printer. The paper web 14 is fed to a first pair of conveyor rollers 16 .

Measuring rollers 22 and a cutting device 24, which are driven by a stepping motor, are provided in a cutting station 20 . As can be seen in Fig. 4, the cutting device 24 comprises a circular knife 400 which is moved against the direction of travel of the paper web against a fixed rail 402 . The paper is held in a fixed position by a paper holder 404 . The circular knife 400 is received on a knife holder 406 , which in turn is slidably mounted on a shaft 408 . A cam 410 attached to the knife holder 406 engages the paper holder 404 and presses the paper against the fixed rail 402 as the knife holder moves over the paper 14 . In operation, the cutting station 20 cuts individual sheets 25 of the photographic inkjet printing paper from the paper web 14 . Before the cutting process, the paper is transported further by the measuring rollers 22 until a sensor 412 detects the front edge of the paper web 14 . Then the paper web 14 is precisely moved a further distance by the measuring rollers 22 and finally stopped.

Looking again at Fig. 1, between the conveyor rollers 16 and the measuring rollers 22, a back printer 26 is provided for printing on the back of the paper web 14 with information. The backside printer 26 may, for example, consist of a low resolution single color ink jet printhead that uses fast drying ink. Alternatively, a dot matrix printer can also be provided as the rear side printer 26 . The back printer 26 prints certain information, such as job and image field number, on the back of the paper web 14 .

Downstream of the cutter 24 is a pair of feed rollers 28 which feed the cut sheets 25 of photographic ink jet printing paper to a first paper belt conveyor. In the preferred embodiments, the various paper belt conveyors mentioned below consist of vacuum belts. The paper belt conveyor has a first vacuum belt 30 with a vacuum suction plate 33 and a second vacuum belt 31 with two independently controllable vacuum suction plates 34 and 35 and a third vacuum belt 32 with a vacuum suction plate 35 '. The first vacuum belt 30 conveys the cut sheets 25 under a print head 36 . The second vacuum belt 31 has a buffer zone controlled by the vacuum suction plate 34 , through which the movement of the second vacuum belt can be separated from the first by printing the sheet by the vacuum of the vacuum suction plate 34 being switched off until the picture is printed. The length of the buffer zone is preferably selected according to the length of the longest expected deduction, z. B. 30 cm with a panorama print of 10 cm width.

As can be seen in FIG. 10, the vacuum belt 30 (as well as the vacuum belts of FIGS. 31 and 32 ) is perforated with holes 30 'and is supported on a pair of bearing and drive rollers 100 , 102 for the vacuum belt. A motor 104 drives the drive roller 102 for the vacuum belt and thus the vacuum belt 30 . The roller 100 is mounted rotatably about its axis 108 in a holder 106 . The holder 106 can be rotated about an axis of rotation 110 in a direction perpendicular to the roller axis 108 , which serves to control the direction of travel of the belt 30 on the rollers 100 and 102 which is true to the track. With the bracket 106 , for example, a drive motor 112 is connected via a ball-bearing guide screw drive 114 , by means of which the bracket 106 can be easily rotated about the axis 110 in order to move the belt 30 on the roller 100 to the right or left. An edge sensor 116 for the vacuum belt, which may for example consist of a pair of LEDs / photosensors, is arranged such that it detects the edge 118 of the belt 30 and provides feedback to a controller (to be described below) which then on the other hand controls the position of the belt 30 on the rollers 100 and 102 precisely.

Looking again at Fig. 1, it can be seen that a full-width, high-resolution color ink-jet printhead 36 is arranged over the first vacuum band 30 , by means of which a color photographic image can be printed on the cut sheets 25 while these are transported by the vacuum belt 30 under the print head. The minimum distance of the För derwalzen 28 from the print head 36 is slightly larger than the maximum length of a cut sheet (z. B. 30 cm for a panorama print of 10 cm wide). The full width ink jet printhead 36 is, for example, a printhead of the type described in US-A-5,812,162. Preferably the printhead is a little wider than the cut sheets 25 (e.g. 12 cm wide) and has a print resolution of 1200 dpi. The preferred ink jet printhead 36 includes a plurality of printhead elements 38 , 40 , 42 , 44 , each of which is supplied with ink of a different color, for example cyan, magenta, yellow and black. The inkjet print head can print at a transport speed of 5 cm per second or about 1000 copies per hour.

In FIG. 11, a coating station 1000 for applying a protective cover layer to the inkjet printing is arranged at the end of the second vacuum belt 31 . In order to prevent the coating material from being applied beyond the edges and onto the belt, the second vacuum belt 31 has the same features as were already described above for precisely controlling the position of the vacuum belt 30 . The coating station consists of a coating head 1002 of the type described in the applicant's parallel application, file number US 091301.198. The coating head 1002 used has nozzles whose diameter is slightly larger than that of an inkjet printhead. As a result, the number of nozzles is also reduced. The coating head 1002 has a container for coating material, which can be supplied via an inlet line 1009 from a supply (not shown). The head is arranged transversely to the paper movement direction and its width is slightly larger than the width of the widest sheet of paper. Two carriers 1008 sit on a shaft 1007 on both sides of the head 1002 . This allows the coating head 1002 to be rotated 90 ° in the direction of arrow B around the shaft to form a cap 1012 which protects the coating head from drying out when the printer is not in use. The cap can be moved back and forth in the direction of arrow A in a known (not shown) manner. In front of the cap, a further image sensor 1006 , which can consist, for example, of a linear CCD line sensor or a photodiode, detects all four edges of the paper sheets 25 and indicates the position of the paper on the vacuum belt 31 as it is transported under the coating head 1002 . The structure and function of the image sensor 1006 for the coating head 1002 can be seen as the image sensor 46 for the print head 36 , which will be described further below (with reference to FIG. 5).

The coating material applied to the cut sheets 25 is intended to give the sheets the desired physical properties, toughness, scratch and abrasion resistance and weather resistance. On the one hand, the coating material in the coating head 1002 must remain liquid, while on the other hand it must dry quickly after being brought onto the paper sheets. The skilled person coating materials of various classes are known. All of these materials contain a binder that ensures cohesion and adhesion to the coated receiving medium. The coating material may contain a solution material for dissolving those which are solid or gel-like at room temperature. A pigment content is not absolutely necessary, but could be provided to change the optical properties of the top layer if desired. Suitable binders include those that form a film due to evaporation of solvents, such as cellulose, vinyl resins, such as PVC or PVA, and natural resins. Other possible binders are:

• - Those that dry through oxidation processes, such as paints and alkyd resins;
• - Those that harden under heat, such as water-soluble alkyd, alkyd resins, acrylic resins and epoxy resins;
• - Those that by applying radiation, including ultraviolet, X-ray curing or electron radiation.

A preferred system using these materials is in US-A-4,426,431 described.

In Fig. 5, an image sensor 46 is, for before the ink-jet printing head 36. B. a linear CCD line sensor, which detects all four edges of the cut sheets 25 when they are transported by the vacuum belt 30 under the print head 36 . The linear image sensor detects a line that is as wide as the print head 36 (z. B. slightly wider than the printing paper sheets 25 ), and has a resolution of z. B. 2700 pixels. In FIG. 5, an example of a suitable linear image sensor array is illustrated. The image sensor 46 has a housing 500 , an objective 502 for focusing an image of the paper and the conveyor belt on an image sensor module 504 and a light source 506 for exposing the paper on the conveyor belt. A suitable image sensor module 504 is, for example, the ILX533K linear CCD color image sensor sold by Sony Corporation. An example of such an arrangement is described in published PCT application 96/38370.

Above the second vacuum suction plate 35 of the vacuum belt 31 , a paper dryer 48 is arranged with a plurality of air doctor blades 50 , which dry the freshly printed images before they reach the end of the conveyor belt. In FIG. 9a it can be seen that the air doctor blades 50 have a plenum 52 with an air inlet 51 for heated compressed air, an air outlet opening 53 and a partition 55 for equalizing the air pressure along the air outlet opening 53 . At a paper transport speed of 5 cm / sec. and a flow velocity of the air flowing to the air, heated to a maximum of 80 ° C., of about 10 m / sec. copies printed with water-based ink can be dried in about 5 seconds. The paper dryer 48 is therefore about 25 cm long.

A cleaning station 57 is provided on the side of the conveyor belt opposite the inkjet print head 36 for cleaning the vacuum belt 30 from paper dust and splashed paint. In Fig. 8 it can be seen in detail that the cleaning station comprises a cleaning head 800 which has the same width as the belt 30th The cleaning head 800 has an outer channel 802 , through which a stream of compressed air can be directed onto the surface of the vacuum belt 30 , and an inner channel 804 , which receives the air stream together with dust or waste removed from the belt and a filter (not shown) feeds. A more detailed description of the cleaning station is contained in the applicant's German parallel application 19914 563.6.

A third vacuum belt 32 downstream of the coating station 1000 has a vacuum suction plate 35 'which holds the paper in place during its transport out of the printer. Control of the belt position, as described for the vacuum belts 30 and 31 , is not required for the vacuum belt 32 . To dry the coated sheets of printing paper, a coating dryer 16 'with a plurality of UV lamps 90 above the vacuum belt 32 is arranged. As can be seen from FIG. 9b, the lamps have a metal lamp housing 91 with an inner polished reflector 92 . A UV Hg 118 tube 93 is arranged in the focal point of the reflector 92 . When using the coating material described in US-A-4,426,431, the drying can be effected by transporting the coated paper sheet to be dried under the UV Hg 118 lamps 90 . The distance between the coated paper sheet and the lamps is about 6.5 cm, the belt speed 5 cm / sec. As a result, the speed of the third vacuum belt 32 is equal to that of the second vacuum belt of the 31st The system has the advantage that a coating with excellent physical properties is achieved and no solvent has to be removed. Another belt cleaning station 57 for removing paper dust from the vacuum belt 32 is arranged on the side of the vacuum belt opposite the UV lamps 90 .

To control the operation of the printer 10 , the various components of the printer are connected to control electronics 54 with a digital processor, for example a microcomputer. In the following, the operation of the printer 10 controlled by the control electronics 54 will now be described. The control electronics receive digital image data, print data for the back and instructions for the print job from an input unit, for example a film scan station or a (not shown) digital image processing station. During the printing process, the control electronics 54 instruct the printer to supply the cutter 24 with a measured piece of the paper web 14 and to print the back-side print data on the paper web 14 before the paper is cut off. The paper sheet 25 with the reverse side print thereon is then cut off from the paper web 14 in the cutting device 24 and fed to the first vacuum belt 30 . When the cut sheet 25 runs onto the vacuum belt, it is detected by the image sensor 46 . The control electronics process the image of the cut sheet 25 , determine the edges of the sheet 25 and generate a print mask corresponding to the borders of the sheet 25 . The print mask is then added to the digital image data and the control electronics 54 feed the digital image data to the inkjet printhead 36 , which then prints the image exactly up to, but not beyond, all four edges of the paper sheet 25 . In this way, overprinting of the ink jet print head 36 on the vacuum belt 30 is prevented in the case of borderless prints. For edge-to-edge prints, the mask is made uniformly narrower than sheet 25 , with the result that the print is properly aligned on the sheet, regardless of any slight misalignments that may occur when the sheet hits the vacuum belt 30 .

The sheets of printing paper are continuously transported along the inkjet printhead 36 . In order to maximize the throughput rate of the printer 10 , the control electronics 54 controls the distance between the cut sheets 25 such that the distance between them is only slightly larger than the width of the image sensor 46 . After printing, the sheets are fed to the second vacuum belt 31 and transported through the dryer 48 where the ink is dried. From the second vacuum belt 31 , the sheets are transferred to the coating station 1000 , where the image side of the sheets, as already described, is provided with a coating material. The image sensor 1006 detects the printed sheet 25 as it enters the coating station. The image of the sheet 25 is processed by the control electronics, the edges of the sheet 25 are detected, and a coating mask is generated which corresponds to the outer limits of the sheet 25 . The coating mask is then used by control electronics 54 to instruct coating head 1002 to coat the image exactly up to, but not beyond, all four sides of sheet 25 . In this way, in the case of rimless prints, it is avoided that the coating head 1002 coats the paper guide plate 1001 beyond the edges. After coating, the sheets are fed to the third vacuum belt and coating dryer 16 where the coating material is dried. The prints are then sent to a collecting compartment or a finishing station (not shown), where they are merged into customer orders and placed in appropriate envelopes.

An alternative embodiment of the printer according to the invention will now be described with reference to FIG. 2. In order to be more flexible with regard to the paper sizes, the printer according to FIG. 2 is equipped with a second paper supply roll 12 'for feeding a paper web 14 ' (for example 9 cm wide) which is narrower than the paper web 14 . The different width paper webs 14 and 14 'who the who the cutting device 24 , controlled by the control electronics 54 , selectively depending on the size requested by the print job instructions supplied. For feeding the paper measured by the feed rollers 16 and 16 'to the measuring rollers 22 of the paper cutting device 24 , paper guides 56 and 56 ' are provided. In this embodiment, the rear side printer 26 is arranged between the measuring rollers 22 and the conveyor rollers 28 . The control electronics 54 works in the manner described above and generates a print mask from the signal supplied by the image sensor 46 , which is merged with the digital image data in order to avoid overprinting on the vacuum belt.

A further alternative embodiment of an ink jet printer according to the invention will now be described with reference to FIG. 3. From this embodiment, like those shown in FIG. 2, there are two paper supplies 58 and 58 ', but in this case the paper supplies consist of cut paper stacks 60 and 60 ' of different sizes. Grippers 62 and 62 'take individual sheets from the top of the stack and lead them to paper feed rollers 64 and 64 ' and from there feed rollers 16 .

As has already been described, the inkjet printers according to the invention are arranged such that the paper is transported linearly from the paper supply through the printer and the dryer to the outlet. This arrangement results in a long, narrow printer. In FIG. 6, a printer assembly is now shown, wherein the pressure and dryer components are arranged parallel to each other and between the dryer 48 and the coating dryer 16 'a print buffer 600 is vorgese hen. The print buffer 600 prevents the dryer 48 from affecting the printhead section of the paper transport path, and changes the paper transport direction by 360 ° when the paper is transported from the dryer 48 via the coating station 1000 to the dryer 16 '. In Fig. 7 it can be seen that the buffer 600 has a first portion of the vacuum belt 700, which is narrower than the narrowest paper width (z. B. 7 cm with a minimum of paper width of 9 cm) and extending in the same direction as the tape 30th A second section 702 is perpendicular to the first section 700 and transports the cut sheet 25 to a third section 704 which transports the cut sheet onto the vacuum belt 31 under the dryer 16 '. As already described, the belt conveyors are designed as vacuum belts. Alternatively, however, electrostatic conveyor belts can also be used in the areas of the web under the printhead and dryer. An example of an electrostatic conveyor belt useful for the invention is described in published European application 0 887 196 A2.

Reference list

10th

Inkjet printer

12th

,

12th

'' Paper supply roll

13

,

13

'' Paper holder

14

Paper web

16

,

16

'' Roller

20th

Cutting station

22

Measuring rollers; driven by stepper motor

24th

Cutter

25th

cut sheet of printing paper

26

Back printer

28

Conveyor rollers

30th

first vacuum belt

30th

'' Holes in the vacuum belt

31

second vacuum belt

32

third vacuum belt

33

Vacuum suction plate

34

Vacuum suction plate

35

Vacuum suction plate

35

'' Vacuum suction plate

36

Inkjet printhead

38

Printhead element

40

Printhead element

42

Printhead element

44

Printhead element

46

linear image sensor

48

Paper dryer

16

'' Coating dryer

50

Air knife

51

Air intake

52

plenum

53

Air outlet opening

54

Control electronics

55

partition wall

56

,

56

'' Paper guide

57

Cleaning station

58

,

58

'' Paper supply

60

,

60

'' cut paper stack

61

,

61

'Edition

62

,

62

'' Gripper

64

,

64

'' Roller

90

UV lamp

91

Lamp housing

92

reflector

93

UV tube

100

Bearing roller for vacuum belt

102

Drive roller for vacuum belt

104

Drive motor for vacuum belt

106

Drive roller bracket

108

Axis of rotation of the drive roller

110

Axis of rotation of the bracket

112

Drive motor of the bracket

114

ball bearing guide screw drive

116

Edge sensor for vacuum belt

118

Edge of the vacuum belt

400

Round knife

402

fixed rail

404

Paper holder

406

Knife holder

408

wave

410

cam

412

sensor

500

casing

502

lens

504

Image sensor module

506

Light source

600

Print buffer

700

first section of the vacuum belt

702

second section of the vacuum belt

704

third section of the vacuum belt

800

Cleaning head

802

outer channel

804

inner channel

1000

Coating station

1001

Paper guide plate

1002

Coating head

1006

Image sensor

1007

wave

1008

carrier

1009

Inlet pipe

1012

cap

Claims (15)

1. Inkjet printer ( 10 ) for the production of photo prints, characterized by

• a) at least one paper supply ( 12 , 12 ', 58 , 58 ') for holding a supply of printing paper,
• b) a paper sheet conveying device consisting of a first, second and third conveyor belt ( 30 , 31 , 33 ), which receives sheets ( 25 ) of the printing paper from the at least one paper supply and transports them through the printer ( 10 ),
• c) a rear side printer ( 26 ) arranged between the at least one paper supply ( 12 , 12 , 58 , 58 ') and the first conveyor belt ( 30 ) for printing on the rear sides of the sheets ( 25 ),
• d) a color ink jet print head ( 36 ) arranged over the first conveyor belt ( 30 ) and extending over the entire printing width for printing an image on the sheets ( 25 ),
• e) a front of the ink jet print head (36) arranged image sensor (46) for detecting the edges of the, under the printhead (36) hindurchtranspor oriented blade (25)
• f) means ( 54 ) for generating a digital mask representing an area of the paper sheet and for applying the digital mask to a currently printed image, thereby preventing overprinting on the vacuum belt ( 30 ),
• g) a second conveyor belt ( 31 ) connected downstream of the first conveyor belt ( 30 ) for taking over the printed sheet ( 25 ) from the first conveyor belt ( 30 ) and for further transport of the printed sheet ( 25 ) by the printer ( 10 ),
• h) a paper dryer ( 48 ) arranged above the second conveyor belt ( 31 ) and having a source ( 50 ) generating an air flow for drying the image on the paper sheet ( 25 ), i) a coating station ( 1000 ) arranged after the second conveyor belt ( 31 ) ) for coating the printed surface of the sheet ( 25 ) by means of a coating head ( 1002 ),
• i) an image sensor ( 1006 ) arranged in front of the coating station ( 1000 ) for detecting the edges of the paper sheet ( 25 ) just being transported under the coating head ( 1002 ),
• j) means ( 54 ) for creating a digital mask representing the position of the paper sheet and for applying the digital mask to a currently coated image, thereby preventing coating over the edges onto a paper guide plate ( 1001 ), and
• k) a third conveyor belt ( 32 ) connected downstream of the coating station for drying the coated sheet ( 25 ) and for transporting it out of the printer ( 10 ).

2. Inkjet printer according to claim 1, characterized by more than one paper supply ( 12 ) for receiving printing paper of different widths and by means ( 54 , 56 , 56 ') for switching between the respective paper stocks ( 12 , 12 ', 58 , 58 ' ) to change the width of the prints just printed in the inkjet printer ( 10 ). 3. Inkjet printer according to claim 1 or 2, characterized in that one of the respective paper supplies consists of paper supply rolls ( 12 , 12 '), each paper supply roll

• a) a paper holder ( 13 , 13 ') for receiving the paper supply roll made of printing paper,
• b) a cutting device ( 24 ) for cutting the paper into individual sheets ( 25 ) and
• c) between the paper supply rolls ( 12 , 12 ') and the cutting device ( 24 ) provided paper conveyor ( 16 , 16 ', 56 , 56 ').

4. Inkjet printer according to claim 1 or 2, characterized in that one of the respective paper supplies consists of single sheet supplies ( 58 , 58 '), each single sheet supply

• a) a support ( 61 , 61 ') for receiving a stack ( 60 , 60 ') of cut paper and
• b) comprises a gripper ( 62 , 62 ') for removing a cut sheet ( 25 ) from the stack ( 60 , 60 ') and for feeding the sheet ( 25 ) to the vacuum belt ( 30 ).

5. Ink jet printer according to claim 1, 2, 3 or 4, characterized in that the back printer ( 26 ) has an ink jet print head. 6. Inkjet printer according to claim 1, characterized in that the image sensors (46, 1006) are linear CCD line sensors. 7. Inkjet printer according to claim 1, characterized in that the first ( 30 ), the second ( 31 ) and the third ( 32 ) paper conveyor belt is formed by vacuum conveyor belts. 8. Inkjet printer according to claim 1, characterized in that the coating station ( 1000 ) comprises the following elements:

• a coating head ( 1002 ) which is movable about a shaft ( 1007 ) which moves the coating head ( 1002 ) from a working position to a rest position,
• - A cap ( 1012 ) which receives the coating head ( 1002 ) when it is in its rest position.

9. Inkjet printer according to claim 8, characterized in that the coating head ( 1002 ) has a container for coating material which is supplied to it from a supply via an inlet line ( 1009 ), the coating head ( 1002 ) having nozzles the width of an inkjet print head for applying the coating material. 10. Inkjet printer according to claim 1, characterized in that the coating dryer ( 16 ') has a plurality of arranged above the third conveyor belt ( 32 ) mercury UV lamps ( 90 ). 11. Inkjet printer according to claim 1, characterized in that the two th conveyor belt ( 31 ) is followed by a print buffer ( 600 ). 12. Inkjet printer according to claim 12, characterized in that the print buffer ( 600 ) changes the paper conveying direction between the paper dryer ( 48 ) and the coating dryer ( 16 '). 13. Inkjet printer according to claim 1, characterized in that further on the inkjet print head ( 36 ) opposite side of the conveyor belt of ( 30 ) a cleaning head ( 800 ) and further on the coating head ( 1002 ) opposite side of the conveyor belt another cleaning head ( 800 ) are provided for cleaning the conveyor belt from paper dust. 14. Inkjet printer according to claim 1, characterized in that the air power source from an air doctor blade ( 50 ) with a plenum ( 52 ), an air inlet ( 51 ), an air outlet ( 53 ) and a partition ( 55 ) arranged in the plenum ( 52 ) to balance the air flow emerging from the air outlet ( 53 ). 15. Inkjet printer according to claim 1, characterized in that the conveyor belt ( 30 ) has a servo control ( 54 , 112 ) for controlling the running direction of the tape, the servo control comprising a sensor ( 116 ) for detecting the tape edge ( 30 ).