DRYER UNIT AND PRINTING MACHINE

Abstract

A dryer unit (18) for applying a dryer gas to a sheet material inside a printing machine comprises a dryer body (20) having a first set (26) of dryer gas output openings (28). These openings (28) are arranged in a substantially regular pattern covering an application width (20a) of the dryer unit (18). Additionally, at least one dryer gas output slot (38) is arranged upstream the first set (26) of dryer gas output openings (28). Furthermore, a printing machine is presented which comprises such a dryer unit (18).

Claims

1. A dryer unit for applying a dryer gas to a sheet material inside a printing machine, the dryer unit comprising: a dryer body having a first set of dryer gas output openings, the first set of dryer gas output openings being arranged in a substantially regular pattern covering an application width of the dryer unit; and at least two dryer gas output slots arranged upstream the first set of dryer gas output openings, wherein neighboring dryer gas output slots of the at least two dryer gas output slots are offset with respect to each other in a direction substantially perpendicular to a width direction and/or the neighboring dryer gas output slots are inclined with respect to the width direction.

2. The dryer unit of claim 1, wherein each of the first set of dryer gas output openings have a substantially circular cross section, and the first set of dryer gas output openings form a rectangular pattern.

3. The dryer unit of claim 1, wherein, the at least two dryer gas output slots extend substantially in the width direction.

4. The dryer unit of claim 1, wherein the neighboring dryer gas output slots overlap in the width direction.

5. The dryer unit of claim 1, further comprising: a second set of dryer gas output openings is provided downstream the first set of dryer gas output openings on the dryer body, wherein the second set of dryer gas output openings form a substantially regular pattern covering the application width of the dryer unit.

6. The dryer unit of claim 5, further comprising: a separation section is interposed between the first set of dryer gas output openings and the second set of dryer gas output openings, wherein the separation section does not comprise openings.

7. The dryer unit of claim 1, further comprising: a first set of gas suction openings provided in a first area of the first set of dryer gas output openings, and/or a second set of gas suction openings is provided in a second area of the second set of dryer gas output openings.

8. The dryer unit of claim 7, wherein the first set of gas suction openings and/or the second set of gas suction openings form a substantially regular pattern covering the application width of the dryer unit.

9. The dryer unit of claim 7, wherein each of the first set of gas suction openings and/or the second set of gas suction openings have a substantially rectangular cross section.

10. The dryer unit of claim 7, further comprising: a third set of gas suction openings is provided upstream the at least two dryer gas output slots, wherein the third set of gas suction openings comprises a line of gas suction openings extending over the application width of the dryer unit.

11. A printing machine comprising: a dryer unit according to claim 1 wherein the dryer unit is an intermediate dryer unit.

Description

[0028] FIG. 1 shows a part of a central drum printing machine 10 having a first printing unit 12 and a second printing unit 14, wherein the two printing units 12, 14 are configured for printing ink of different color on a sheet material 16 which travels through the printing machine 10 along a direction 16a over a central drum 15.

[0029] The printing machine 10 also comprises a dryer unit 18 which is an intermediate dryer unit being configured for drying ink applied to the sheet material 16 by the first printing unit 12 before the respective part of the sheet material enters the second printing unit 14.

[0030] Even though the sheet material 16 is represented as a continuous web of sheet material, the printing machine 10 may also be configured for processing single sheets thereof.

[0031] The dryer unit 18 may be seen in in more detail in FIGS. 2 to 3.

[0032] It comprises a dryer body 20 extending substantially over an application width 20a of the dryer unit 18. The application width 20a is oriented along a width direction 20b of the dryer unit 18.

[0033] In the example the application width 20a corresponds to the width of the sheet material 16. In other words, the dryer unit 18 is configured for supplying a dryer gas over the entire with of the sheet material 16 in order to dry ink applied thereto.

[0034] To this end the dryer body 20 is equipped with a dryer gas inlet port 22 which may be connected to a pump supplying dryer gas to dryer unit 18.

[0035] The dryer body 20 is also equipped with a dryer gas outlet port 24 being configured for discharging dryer gas which is loaded with humidity and residues of ink as will be explained later.

[0036] In order to apply the dryer gas to the sheet material 16 a first set 26 of dryer gas output openings 28 is provided on a discharge side 30 of the dryer body 20 (cf. FIG. 3). For the ease of representation only some of the dryer gas output openings 28 are equipped with a reference sign.

[0037] The dryer gas output openings 28 are arranged in a rectangular pattern comprising four full lines of dryer gas output openings 28, each of them covering the application width 20a. Additionally, a fifth line of dryer gas output openings 28 is provided, only comprising some gas output openings 28, i.e. not being fully staged with gas output openings 28.

[0038] Each of the dryer gas output openings 28 has a substantially circular cross section and all these dryer gas output openings 28 are fluidically connected to the dryer gas inlet port 22.

[0039] Additionally, a second set 32 of dryer gas output openings 34 is provided on the discharge side 30 of the dryer body 20 (cf. FIG. 3). Again, only some of the dryer gas output openings 34 are equipped with a reference sign for the ease of representation.

[0040] The second set 32 is arranged downstream the first set 26, wherein a separation section 36 is interposed between the first set 26 and the second set 32.

[0041] The separation section 36 does not comprise any openings.

[0042] Also the dryer gas output openings 34 of the second set 32 form a substantially rectangular pattern comprising five lines of dryer gas output openings 34 covering the application width 20a of the dryer unit 18.

[0043] Each of the dryer gas output openings 34 has a substantially circular cross section and all these dryer gas output openings 34 are fluidically connected to the dryer gas inlet port 22.

[0044] Furthermore, a series of dryer gas output slots 38 is arranged upstream the first set 26 of dryer gas output openings 28.

[0045] All dryer gas output slots 38 extend substantially in the width direction 20b of the dryer unit 18 and are slightly inclined with respect thereto.

[0046] Moreover, the slots 38 are arranged such that neighboring slots 38 overlap in the width direction 20b.

[0047] In other words, adjacent ends of neighboring slots 38 are offset with respect to each other in a direction substantially perpendicular to the width direction 20b.

[0048] All slots 38 are fluidically connected to the dryer gas inlet port 22.

[0049] It is noted that the dryer gas output openings 28, the dryer gas output openings 34 and the dryer gas output slots 38 are connected to the dryer gas inlet port 22 via a supply duct being located inside the dryer body 20.

[0050] Consequently dryer gas is applied to the sheet material 16 by the slots 38, the openings 28 and the openings 34 while the sheet material 16 travels in the direction 16a besides the discharge side 30 of the dryer body 20. Thereby ink applied to the sheet material 16 is dried.

[0051] In order to evacuate dryer gas being loaded with humidity and ink residues, a first set 40 of gas suction openings 42 is provided in the area of the first set 26 of dryer gas output openings 28.

[0052] These gas suction openings 42 are arranged in a rectangular pattern covering the application width 20a of the dryer unit 18. Moreover, the gas suction openings 42 are arranged such that the dryer gas output openings 28 are arranged in between the gas suction openings 42. This is the case in the width direction 20b and in a direction perpendicular to the width direction 20b.

[0053] Furthermore, the gas suction openings 42 of the first set 40 are all fluidically connected to the outlet port 24. Consequently, during operation of the dryer unit 18 the dryer gas applied to the sheet material by the dryer gas output openings 28 and at least a portion of the dryer gas applied to the sheet material 16 by the dryer gas output slots 38 will be evacuated via the gas suction openings 42 after having interacted with the sheet material 16.

[0054] Moreover, a second set 44 of gas suction openings 46 is provided in the area of the second set 32 of dryer gas output openings 34.

[0055] Also these gas suction openings 46 are arranged in a rectangular pattern covering the application width 20a of the dryer unit 18. Like the gas suction openings 42, the gas suction openings 46 are arranged such that the dryer gas output openings 34 are arranged in between the gas suction openings 46. This is the case in the width direction 20b and in a direction perpendicular to the width direction 20b.

[0056] Also the gas suction openings 46 of the second set 44 are all fluidically connected to the outlet port 24. Thus, during operation of the dryer unit 18 the dryer gas applied to the sheet material by the dryer gas output openings 34 will be evacuated via the gas suction openings 46 after having interacted with the sheet material 16.

[0057] A supplementary third set 48 of gas suction openings 50 is provided upstream the dryer gas output slots 38.

[0058] In the example shown these gas suction openings 50 are arranged along a single line extending over the application width 20a of the dryer unit 18.

[0059] These gas suction openings 50 are fluidically connected to the outlet port 24 and will evacuate dryer gas having been applied to the sheet material 16 by the slots 38.

[0060] The suction openings 42 of the first set 40, the suction openings 46 of the second set 44 and the suction openings 50 of the third set 48 have a substantially rectangular cross section.