CN211000534U

CN211000534U - Machine for printing sheets of printing material with ink

Info

Publication number: CN211000534U
Application number: CN201920026279.9U
Authority: CN
Inventors: A·云格尔; T·施密特; K·戈尔
Original assignee: Heidelberger Druckmaschinen AG
Current assignee: Heidelberger Druckmaschinen AG
Priority date: 2018-01-10
Filing date: 2019-01-08
Publication date: 2020-07-14
Anticipated expiration: 2029-01-08
Also published as: DE202018000418U1; DE102018200260A1

Abstract

A machine for printing a sheet of substrate material with ink, comprising: a conveyance path (4); a first transport roller (4 a); a second transport roller (4 b); at least one inkjet print head (3); a blowing device (5) which acts on at least one section of the second conveyor drum (4b) with tempered blowing air (6, 6 b); a third transport roller (4 c); and at least one dryer (3') generating thermal energy. The blowing device (5) comprises at least one air guide plate (5a) which directs the temperature-controlled blowing air to the first transport cylinder (4a) and thus to the printing material sheet (2) there. The invention advantageously achieves a sufficient temperature control of the machine parts and the printing material, and in particular achieves only insignificant temperature differences between the transport cylinder and the transported printing material and a uniform temperature distribution in the printing material.

Description

Machine for printing sheets of printing material with ink

Technical Field

The utility model relates to a machine for printing material page with printing ink.

The present invention relates to the technical field of the image industry and there in particular to the field of industrial Inkjet printing (Inkjet) on flat substrates, i.e. in particular to the field of applying liquid inks to a printing material in the form of a sheet, preferably made of paper, cardboard, paperboard or plastic, and drying.

Background

In the known DOD inkjet printing method (drop-on-demand) liquid ink is applied by generating a printed image on a flat printing substrate, wherein an inkjet printing head (abbreviated to "head") with individually controllable nozzles produces the finest ink drops, preferably in the picoliter range, depending on the image to be printed, and transfers them as printing dots to the printing substrate in a contactless manner. The nozzle can be actuated by means of a piezo actuator.

In so-called water-based ink-jet printing, the liquid ink comprises a portion of the water for receiving the colorant, especially a pigment. The colorant is transferred to the substrate by means of droplets produced by an inkjet print head. Subsequently, the water likewise transferred here is removed from the print substrate, preferably by thermal drying, for example by irradiation with infrared radiation.

Sufficient drying of water-based inks on moving printing materials requires a dryer for generating high spatial power densities, which evaporates all excess water within a short dwell time of the printing material in the active region of the dryer. Thus, high energy is input into the machine in the area of the dryer. This can therefore lead to undesirable thermal expansion of machine parts, for example side walls or rollers.

DE 112015004269T 5 discloses an image generation device. A gas compressor is used for cooling the impression cylinder. The gas compressor is disposed below the impression cylinder and blows cooled air toward the impression cylinder.

Ink jet printers known under the product name "Primefire" and developed by heidelberg printer gmbh of germany (Heidelberger druckmaschen AG, Deutschland) for industrial production ink jet print paper sheets in a water-based manner. The machine comprises seven successive printing stations belonging to the so-called "jet cylinders" which transfer the colours CMYK (cyan, magenta, yellow and black) and OGV (orange, green, violet) onto the paper with a printing head. The applied ink was dried by using an IR dryer. In this machine, the temperature of the spray drum is regulated by blowing air from above, from which the print head is also pressed against the paper.

However, in this prior art, in particular, when the machine is stopped, i.e., when the sheet transport is stopped, a problem of insufficient cooling can occur.

SUMMERY OF THE UTILITY MODEL

The object of the present invention is therefore to provide an improvement over the prior art which allows sufficient temperature control of the machine parts and the printing material (in particular when the machine is parked) and which allows in particular only insignificant temperature differences between the transport cylinder and the transported printing material and a uniform temperature distribution in the printing material.

According to the invention, this task is solved by a machine according to the invention.

Advantageous and thus preferred developments of the invention emerge from the description and the drawing.

The substrate material may include the following materials: paper, cardboard (also corrugated cardboard) or plastic, respectively, as sheets.

The transport cylinder may comprise a rotating or rotatable cylinder which transports the sheet of printing material, in particular a cylinder with a circular cross section or a circular cross section reduction, preferably an impression cylinder or a so-called transfer cylinder (Umf ü hrtrommel).

The machine according to the invention for printing a sheet of printing material with ink comprises: a transport path for a sheet of printing material, a first transport cylinder of the transport path, a second transport cylinder arranged downstream of the first transport cylinder in the transport path, at least one inkjet print head on the circumference of the second transport cylinder, a blowing device for applying temperature-regulated blowing air to at least one section of the second transport cylinder, a third transport cylinder arranged downstream of the second transport cylinder in the transport path, and at least one heat-generating dryer, characterized in that the blowing device comprises at least one air guide plate which guides the temperature-regulated blowing air to the first transport cylinder and thus to the sheet of printing material there.

The invention advantageously achieves a sufficient temperature control of machine parts (e.g., transport cylinders) and printing material (in particular when the machine is parked) and, in particular (in order to generate a high printing quality), only insignificant temperature differences between the transport cylinders and the printing material being transported and a uniform temperature distribution in the printing material.

According to the utility model discloses, the temperature of second delivery cylinder and substrate can be adjusted until several degrees centigrade.

In this respect, the invention provides at least one air guide plate which guides tempered, in particular cooled blowing air to the first transport cylinder and thus to the printing material sheet there. The blowing air of the blowing device thus not only adjusts the temperature, in particular cools, the second transport cylinder, but also adjusts the temperature, in particular cools, the printing material before it is printed, which is located on the second transport cylinder during printing. In this way, the temperature difference between the second transport cylinder and the printing material supplied to said second transport cylinder can be kept sufficiently small. In this case, the guide plate is used as a simple component, preferably to guide excess blowing air of the blowing device to the first transport cylinder and thus to the sheet of printing material there. In this way, the blowing device (in addition to the function of tempering the second transport cylinder) has the additional function of tempering the sheets as well. The guide plate takes up little installation space and can therefore be arranged in a simple manner in the machine, preferably close to the blowing device, and preferably below the first transport cylinder or below the sheet guide plate of the first transport cylinder.

A preferred development of the invention can be characterized in that the machine comprises a blowing box which is arranged substantially below the second conveying drum and which outputs substantially upwardly tempered blowing air. The blowing box preferably directs the cooled blowing air directly to the second conveyor drum. It is advantageous here if the blowing box is substantially opposite the printing head with respect to the second transport drum (head "up" and blowing box "down"), and therefore has sufficient installation space for the blowing box. The head also does not interfere with the blowing air flow. The blowing box (its size, its shape and/or its structure) can influence the blowing air distribution in such a way that the blowing air distribution is as uniform as possible substantially over the width of the machine or at least of the second transport drum.

The flow rate of the blowing air is selected to be so low that disturbing influences on a smooth sheet running can be eliminated and contaminated ambient air can be blown together as little as possible. The volume flow is selected to be so large that sufficient tempering is achieved.

The utility model discloses a preferred extension's characteristic can lie in, and the jetting case is connected with cooler, air-blower and filter.

A preferred embodiment of the invention can be characterized in that the air guide plate is arranged substantially below the first conveying roller or below a sheet guide plate associated with the first conveying roller. In this way, it is possible to implement with simple, cost-effective and space-saving components: the excess blowing air of the blowing device reaches the first transport drum or its sheet guide. In addition, the second transport cylinder and the sheet are exposed to blowing air at the same temperature in this way.

The utility model discloses a preferred extension's characteristic can lie in, the jetting device has at least one other air guide, other air guide will be through the jetting air direction third transport cylinder that adjusts the temperature.

A preferred development of the invention can be characterized in that the further air guide plate is arranged substantially below the third transport cylinder or below a further sheet guide plate associated with the third transport cylinder. In this way, it is possible to implement with simple, cost-effective and space-saving components: the excess blowing air of the blowing device reaches the third transport drum or its sheet guide.

A preferred development of the invention can be characterized in that the machine comprises an air knife which blows tempered blowing air into the outlet wedge between the second conveying roller and the third conveying roller. In this way it is possible to: the residual heat of the dryer does not reach the second transport drum or only to an insignificant extent (in particular when the machine is stopped).

A preferred development of the invention can be characterized in that the air knife is supplied with blowing air, wherein the blowing air has a first volume flow during a printing operation of the machine and a second volume flow which is higher relative to the first volume flow during a standstill of the machine. In this way it is possible to: the residual heat of the dryer during machine standstill does not or only to an insignificant extent lead to local heating and thermal expansion of the second transport drum. Preferably, the air knife generates an air curtain with such a high volume flow and such a low flow rate that an interfering heat transfer from the dryer to the second transport drum is prevented, so that the sheet run is not disturbed and/or contaminants from the environment are not blown together. At the same time, the blowing air generation through the blowing box can be reduced or interrupted in order to prevent dust from being blown up to the print head.

The utility model discloses a preferred extension's characteristic can lie in, and jetting case constitutes the shielding part for the bottom of machine jointly with air guide and other air guide, the shielding part shields the dust. Dust, in particular paper dust, accumulates over time on the bottom of the machine. The utility model discloses an extension shielding this bottom to can prevent effectively that the dust from being blown upwards to the cylinder or even blowing to the high sensitivity's of printing head.

A preferred embodiment of the invention can be characterized in that the machine is a 7-color inkjet printer which prints water-based ink with the aid of a plurality of inkjet print heads and the ink is thermally dried with the aid of at least one dryer.

The generation of blowing air (of blowing boxes and/or of air knives) can preferably be carried out in a controlled manner, for example according to the following table:

the utility model discloses an extend the scheme with the utility model discloses a characteristic of embodiment also can make up wantonly each other and constitute the utility model discloses a favorable extend scheme. Furthermore, the development of the invention can have individual features or combinations of features (disclosed in the above paragraph "technical field of the invention").

Drawings

The invention and its preferred developments are further described below with reference to the drawings according to preferred embodiments. The figures show:

figure 1 is a machine according to the invention.

Detailed Description

Fig. 1 shows a preferred embodiment of a machine 1 according to the invention for printing a sheet 2 of printing material with ink. The ink is transferred to the printing material sheet by means of a plurality of inkjet printing heads 3 and dried by means of a dryer 3' (or a plurality of dryers). The inks are water-based inks or inks (e.g., of seven colors cyan, magenta, yellow (CMY) and orange, green, violet (OGV) and black (K)). The dryer is a thermal dryer, preferably an infrared dryer and/or a hot air dryer.

The machine 1 comprises a transport path 4 for sheets 2 of printing material. The transport path has a plurality of transport cylinders, which are successive one behind the other and each transport a sheet, at least one first transport cylinder 4a, a second transport cylinder 4b and a third transport cylinder 4 c. The

transport cylinders

4a and 4c are double, whereas the transport cylinder 4b is four times larger, i.e. it has four sections guiding the sheets. The transport cylinder 4b is also referred to as "jet cylinder" since the print head 3 is assigned to it. Sheet transport occurs substantially in the transport direction 15 through the machine 1.

For the purpose of tempering, in particular for cooling, the second conveyor drum 4b, a blowing device 5 is arranged below said second conveyor drum. The blowing device comprises a blowing box 5b which generates tempered blowing air 6 and blows it as blowing air 6b (preferably upwards in direction 16) towards the second conveyor drum 4 b. The blowing box 5b is connected to a cooler 7 for air, preferably a water-cooled cooler, a blower 8 for air and an air filter 9. The blowing box may extend substantially over the entire width of the spray drum 4 b. The box is preferably closed on the sides and open upwards or provided with blowing openings or blowing nozzles.

Furthermore, the blowing device 5 comprises an air guide plate 5 a. Which is arranged in front of the blowing box 5b in the conveying direction 15. Excess blowing air 6 is directed by the air guide plate 5a as blowing air 6a to the first conveyor roller 4 a. The blowing air 6a is sucked there by the fans of the sheet guide 10a and blown toward the first transport cylinder 4a or the printing material sheet 2 guided by it in order to guide the sheet. The air guide 5a can be curved or, as shown, single-bent or multi-bent and in this way has a contour corresponding to the sheet guide 10 a. The air guide plate may be fitted on the blowing box and may extend over substantially the entire width of the spray drum 4 b. The air guide forms together with the sheet guide an air channel which extends substantially opposite to the conveying direction 15. The air guide plate may be made of a plate material.

Furthermore, the blowing device 5 has a further air guide 5 c. The additional air guide plate directs the excess blowing air 6 as blowing air 6c to the additional sheet guide plate 10 c. The fan of the sheet guide sucks the blowing air 6c and blows it toward the third transport cylinder 4c or the printing material sheet 2 guided by it in order to guide the sheet. The air guide 5c can likewise be curved or, as shown, single-bent or multiply-bent and in this way have a contour corresponding to the sheet guide 10 c. The air guide plate may be fitted on the blowing box and may extend over substantially the entire width of the spray drum 4 b. The air guide forms together with the sheet guide an air channel which extends substantially in the transport direction 15. The air guide plate can be made of a sheet material.

Furthermore, the machine 1 comprises an air knife 11 blowing air 6d towards the exit wedge 12. The air knife is preferably arranged above the third transport cylinder 4 c. The air knife may be connected to a cooler 7, a blower 8 and a filter 9. Alternatively, the air knife may be connected to the blowing box 5 b.

The blowing device 5 also forms a shield 13 with respect to the bottom 14 of the machine 1. In this way, paper dust on the bottom is prevented from being sucked by the sheet guides 10a and 10c or their fans and blown up to the high-sensitivity printing head 3. The shield thus formed preferably extends below the three

rollers

4a, 4b and 4c, or at least below the transfer position between the roller 4b and the

rollers

4a and 4b and between the

rollers

4b and 4 c.

The blowing air supply is preferably controlled. For this purpose, a control device may be provided.

List of reference numerals

1 machine

2 sheet of printing material

3 ink jet print head

3' dryer

4 conveying path

4a first conveying roller

4b second transport cylinder

4c third transport cylinder

5 blowing device

5a air guide plate

5b blowing box

5c additional air guide plate

6 blowing air

6a-6d blowing air

7 cooler

8 blower

9 Filter

10a page guide plate

10c additional sheet guides

11 air knife

12 exit wedge

13 shield part

14 bottom

15 direction of conveyance

16 upward direction

Claims

1. A machine for printing a sheet of substrate material with ink, comprising:

a transport path (4) for a sheet (2) of printing material,

a first transport roller (4a) of the transport path,

a second conveyor roller (4b) arranged downstream of the first conveyor roller in the conveying path,

at least one inkjet printing head (3) on the periphery of the second transport drum,

a blowing device (5) which applies tempered blowing air to at least one section of the second conveyor drum (4b),

a third transport drum (4c) arranged downstream of the second transport drum in the transport path, and

at least one dryer (3') generating thermal energy,

it is characterized in that the preparation method is characterized in that,

the blowing device (5) comprises at least one air guide plate which guides the tempered blowing air to the first transport cylinder (4a) and thus to the printing material sheet (2) located there.

2. The machine of claim 1, wherein the machine is,

it is characterized in that the preparation method is characterized in that,

the machine comprises a blowing box (5b) which is arranged below the second conveyor drum (4b) and which outputs upwardly tempered blowing air.

3. The machine of claim 2, wherein the machine further comprises a drive motor,

it is characterized in that the preparation method is characterized in that,

the blowing box (5b) is connected with a cooler (7), a blower (8) and a filter (9).

4. The machine of any one of claims 1 to 3,

it is characterized in that the preparation method is characterized in that,

the air guide plate is arranged below the first conveying roller (4a) or below a sheet guide plate associated with the first conveying roller.

5. The machine of claim 2 or 3,

it is characterized in that the preparation method is characterized in that,

the blowing device (5) has at least one further air guide plate which directs the temperature-controlled blowing air to the third conveyor drum (4 c).

6. The machine of claim 5, wherein the first and second rollers are mounted on a single frame,

it is characterized in that the preparation method is characterized in that,

the further air guide plate is arranged below the third transport cylinder (4c) or below a further sheet guide plate associated with the third transport cylinder.

7. The machine of any one of claims 1 to 3,

it is characterized in that the preparation method is characterized in that,

the machine comprises an air knife (11) blowing tempered blowing air into an exit wedge (12) between the second transport drum (4b) and the third transport drum (4 c).

8. The machine of claim 7, wherein the first and second rollers are mounted on a single carriage,

it is characterized in that the preparation method is characterized in that,

the air knives (11) are supplied with blowing air, wherein the blowing air has a first volume flow during a printing operation of the machine (1) and a second volume flow which is higher relative to the first volume flow during a standstill of the machine.

9. The machine of claim 5, wherein the first and second rollers are mounted on a single frame,

it is characterized in that the preparation method is characterized in that,

the blowing box (5b) together with the air guide plate and the further air guide plate forms a shield (13) with respect to a bottom (14) of the machine (1), which shield shields against dust.

10. The machine of any one of claims 1 to 3,

it is characterized in that the preparation method is characterized in that,

the machine (1) is a 7-color inkjet printer which prints water-based inks by means of a plurality of inkjet print heads (3) and the inks are thermally dried by means of at least one dryer (3').