GB2032852A

GB2032852A - Inking apparatus

Info

Publication number: GB2032852A
Application number: GB7935368A
Authority: GB
Original assignee: Polygraph Leipzig Kombinat Veb
Current assignee: Polygraph Leipzig Kombinat Veb
Priority date: 1978-10-19
Filing date: 1979-10-11
Publication date: 1980-05-14
Also published as: FR2439087B3; SU1036572A1; DD139113A1; CS222975B1; FR2439087A1; DE2939296A1; BG34807A1; DE2939296C2; GB2032852B

Abstract

An inking apparatus for a rotary offset and a letter press printing machine comprises a wedge inkwell, a ductor (1) rotatable against a doctor blade (3) of the wedge inkwell (2) as well as a settable doctor blade (8) for the ductor (1) and disposed above the wedge ink well (2). The doctor blade (3) of the wedge inkwell (2) is disposed at a small gap S tangential to the ductor (1) and projects beyond the intersection (4) with the normal (5) of the ductor (1) against the direction of rotation thereof. The blade (3) is preferably resiliently mounted. <IMAGE>

Description

SPECIFICATION Inking Apparatus The present invention relates to an inking apparatus for a rotary offset and letter press printing machine.

US-PS 3 288 061 discloses an inking apparatus comprising a wedge inkwell, a ductor rotating against a doctor blade of the wedge inkwell and an adjustable additional ductor blade disposed above the wedge inkwell.

A disadvantage of prior art proposals are that the ink which is partially wiped off from the ductor by the blade of the wedge inkwell, must be collected by a container disposed under the inkwell and subsequently pumped back into the wedge inkweil. This presents difficulties in the case of highly viscous inks, which are used particularly in offset printing.

According to the present invention there is provided an inking apparatus for a rotary offset and letter press printing machine, comprising an inkwell, a rotatable ductor, a selectively positionable first doctor blade disposed above the inkwell, and a second doctor blade disposed in a general plane at a gap from the circumference of the ductor, the second doctor blade having a free end directed against the intended direction of rotation of the ductor and disposed beyond the intersection of the general plane with a plane perpendicular thereto and passing which extends through the axis of rotation of the ductor.

The inkwell may be a wedge inkwell.

The second doctor blade may be resiliently deformable in the region of gap.

The inking apparatus may comprise means to adjust the gap.

Embodiments of the present invention will now be more particularly described by way of example and with reference to the accompanying drawing in which: Figure 1 shows a schematic side elevation of an inking apparatus, and Fig. 2 shows a modification of the apparatus shown in Fig. 1 and provided with a resiliently mounted second doctor blade.

Referring to Fig. 1, a wedge inkwell 2 is shown in an operative setting so hinged to a ductor 1 that a doctor blade 3 fastened to the inkwell is spaced at a small gap 'S' from the ductor 1. The doctor blade 3 has a free end directed against the direction of rotation of the ductor 1 and disposed beyond the intersection of the general plane of the doctor blade 3 with a plane perpendicular thereto and passing through the axis of rotation of ductor 1. This provides for a wedgeshaped ink input at the wedge inkwell 2.

The width of gap 'S' between the ductor 1 and doctor blade 3 is adjustable with the aid of several set-screws 6 distributed over the length of and guided in the inkwell 2.

Arranged above the wedge inkwell 2 is a doctor blade 8, which is mounted to a pivotable support 7. The doctor blade 8 regulates the ink and is adjustable in its spacing from the ductor 1 by several set-screws 9 distributed over the length of and guided in the support 7.

An inking arrangement (not shown) associated with a grooved roller 10 communicates with the ductor 1.

Fig. 2 shows a modification of the embodiment shown in Fig. 1 in which the doctor blade 3 is resiliently mounted. The end of the doctor blade 3 bearing against the doctor 1 is supported through set-screws 6 against an intermediate member 11, which is fastened under bias to the wedge inkwell 2 by several screws 13 each equipped with two plate springs 1 2.

When the ductor 1 rotates against the doctor blade 3 the ductor 1 is inked in the wedge inkwell 2. The ink is subsequently wiped off by the doctor blade 8 up to the desired thickness in correspondence with the setting of the set-screws 9.

After a part of the ink strand, as result of ink splitting, has been delivered to the groove roller 10, the remaining residual ink is completely returned from the ductor 1 through the gap 'S' which narrows in wedgeshape into the wedge inkwell 2, whilst ink pollutions also pass through the gap 'S' without difficulties.

During operation, the accumulation pressure of the ink leads to a widening of the gap 'S' but when the ductor 1 is stationary the gap 'S' narrows so that the ink can not flow out of the wedge inkwell.

In the modification shown in Fig. 2, the described effect can develop particularly advantageously by reason of the additional resilient support of the doctor blade 8 relative to the wedge inkwell 2.

The installation of an additional collecting container for the ink below the wedge inkwell 2 and devices for the return of the ink into the inkwell are not required.

Due to the gap 'S' at the inkwell, the residual ink is not wiped off from the ductor, but guided back into the inkwell. Reduction of the influence of ink pollution on regulation in consequence of the ink container in the latter are further advantages of inking apparatuses embodying the present invention compared with prior art inking apparatuses.

1. An inking apparatus for a rotary offset and letter press printing machine, comprising an inkwell, a rotatable ductor, a selectively positionable first doctor blade disposed above the inkwell, and a second doctor blade disposed in a general plane at a gap from the circumference of the ductor, the second doctor blade having a free end directed against the intended direction of rotation of the ductor and disposed beyond the intersection of the general plane with a plane perpendicular thereto and passing through the axis of rotation of the ductor.

2. An inking apparatus as claimed in claim 1, wherein the inkwell is a wedge inkwell.

3. An inking apparatus as claimed in either claim 1 or claim 2, wherein the second doctor

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Inking Apparatus The present invention relates to an inking apparatus for a rotary offset and letter press printing machine. US-PS 3 288 061 discloses an inking apparatus comprising a wedge inkwell, a ductor rotating against a doctor blade of the wedge inkwell and an adjustable additional ductor blade disposed above the wedge inkwell. A disadvantage of prior art proposals are that the ink which is partially wiped off from the ductor by the blade of the wedge inkwell, must be collected by a container disposed under the inkwell and subsequently pumped back into the wedge inkweil. This presents difficulties in the case of highly viscous inks, which are used particularly in offset printing. According to the present invention there is provided an inking apparatus for a rotary offset and letter press printing machine, comprising an inkwell, a rotatable ductor, a selectively positionable first doctor blade disposed above the inkwell, and a second doctor blade disposed in a general plane at a gap from the circumference of the ductor, the second doctor blade having a free end directed against the intended direction of rotation of the ductor and disposed beyond the intersection of the general plane with a plane perpendicular thereto and passing which extends through the axis of rotation of the ductor. The inkwell may be a wedge inkwell. The second doctor blade may be resiliently deformable in the region of gap. The inking apparatus may comprise means to adjust the gap. Embodiments of the present invention will now be more particularly described by way of example and with reference to the accompanying drawing in which: Figure 1 shows a schematic side elevation of an inking apparatus, and Fig. 2 shows a modification of the apparatus shown in Fig. 1 and provided with a resiliently mounted second doctor blade. Referring to Fig. 1, a wedge inkwell 2 is shown in an operative setting so hinged to a ductor 1 that a doctor blade 3 fastened to the inkwell is spaced at a small gap 'S' from the ductor 1. The doctor blade 3 has a free end directed against the direction of rotation of the ductor 1 and disposed beyond the intersection of the general plane of the doctor blade 3 with a plane perpendicular thereto and passing through the axis of rotation of ductor 1. This provides for a wedgeshaped ink input at the wedge inkwell 2. The width of gap 'S' between the ductor 1 and doctor blade 3 is adjustable with the aid of several set-screws 6 distributed over the length of and guided in the inkwell 2. Arranged above the wedge inkwell 2 is a doctor blade 8, which is mounted to a pivotable support 7. The doctor blade 8 regulates the ink and is adjustable in its spacing from the ductor 1 by several set-screws 9 distributed over the length of and guided in the support 7. An inking arrangement (not shown) associated with a grooved roller 10 communicates with the ductor 1. Fig. 2 shows a modification of the embodiment shown in Fig. 1 in which the doctor blade 3 is resiliently mounted. The end of the doctor blade 3 bearing against the doctor 1 is supported through set-screws 6 against an intermediate member 11, which is fastened under bias to the wedge inkwell 2 by several screws 13 each equipped with two plate springs 1 2. When the ductor 1 rotates against the doctor blade 3 the ductor 1 is inked in the wedge inkwell 2. The ink is subsequently wiped off by the doctor blade 8 up to the desired thickness in correspondence with the setting of the set-screws 9. After a part of the ink strand, as result of ink splitting, has been delivered to the groove roller 10, the remaining residual ink is completely returned from the ductor 1 through the gap 'S' which narrows in wedgeshape into the wedge inkwell 2, whilst ink pollutions also pass through the gap 'S' without difficulties. During operation, the accumulation pressure of the ink leads to a widening of the gap 'S' but when the ductor 1 is stationary the gap 'S' narrows so that the ink can not flow out of the wedge inkwell. In the modification shown in Fig. 2, the described effect can develop particularly advantageously by reason of the additional resilient support of the doctor blade 8 relative to the wedge inkwell 2. The installation of an additional collecting container for the ink below the wedge inkwell 2 and devices for the return of the ink into the inkwell are not required. Due to the gap 'S' at the inkwell, the residual ink is not wiped off from the ductor, but guided back into the inkwell. Reduction of the influence of ink pollution on regulation in consequence of the ink container in the latter are further advantages of inking apparatuses embodying the present invention compared with prior art inking apparatuses. CLAIMS

3. An inking apparatus as claimed in either claim 1 or claim 2, wherein the second doctor blade is resiliently deformable in the region of the gap.

4. An inking apparatus as claimed in any one of the preceding claims, comprising means to adjust the gap.

5. An inking apparatus as hereinbefore described with reference to Fig. 1 of the accompanying drawings.

6. An inking apparatus as claimed in claim 5 and modified substantially as hereinbefore described with reference to Fig. 2 of the accompanying drawings.