GB2448963A

GB2448963A - Inkjet printing on cylindrical or spherical components

Info

Publication number: GB2448963A
Application number: GB0804943A
Authority: GB
Inventors: Darren Lee Haward; Pete Stuart Whiffen
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-05-01
Filing date: 2008-03-18
Publication date: 2008-11-05
Also published as: WO2008132217A1; WO2008132218A1; GB0804943D0; GB0708393D0

Abstract

An ink jet printer for printing on non-planar objects, such as cylindrical (100, 200) or spherical (100, 300) objects comprises an ink jet printing head (110) adapted to release jets of ink (120) in a first direction (D). Means are provided for rotating a cylindrical component (100, 200) about its central axis, the central axis (130, 230) of the cylindrical component being perpendicular to the first direction D. The ink jet printer for printing onto a spherical component (100, 300), means for rotating the spherical component (100, 300) are arranged to rotate the spherical component (100, 300) about an axis (130, 330) through the centre of the spherical component (100, 300), the axis (130, 330) being perpendicular to the first direction (D). The invention solves the problems associated with printing images onto cylindrical or spherical objects accurately, repeatably and/or rapidly.

Description

Digital Ink Jet Printing on Cylindrical or Spherical Components

Field of the Invention

The field of this invention relates to the field of ink jet printing. The invention is applicable to printing on non-planar objects, such as cylindrical or spherical objects.

Background of Invention

It is known for manufacturers to print onto cylindrical or spherical components.

In general, known techniques rely on creating a physical copy of the image, e.g. on a plastic foil. Such a foil may then be wrapped around and/or stuck onto the component. Alternatively, the copy of the image may be made on a mesh. The mesh is then used as a mask, through which paint is forced onto the component. For an image that comprises more than one colour, multiple masks are needed. Each colour must be applied using a different mask, in a separate printing step.

The prior art methods involve many disadvantages. These include the inaccuracy introduced by the process of copying an image. In addition, if a foil is created, then a durable bond must be created to stick the foil to the component.

If a mask is used, then there is the difficulty of aligning different masks accurately for the different colours. A variety of chemicals must be used in the processes that are used to create masks, and these chemicals need to be stored, and disposed of, appropriately. The electromechanical nature of the printing process provides an upper limit to the rate of throughput of components that are being subjected to the mask printing process. The component must be moved towards and away from the mask in order for the printing step to take place, and this movement can only be achieved with finite acceleration and deceleration.

Finally, problems can arise due to the shape of the object onto which an image is to be printed. As a consequence, images can sometimes only be printed onto restricted areas of components, i.e. only onto some parts of components. If the cylindrical component is, for example, a pen, then it is likely to have a pen cover and a clip for attachment to clothing. The clip makes access to part of the pen impossible for some prior art methods. Although pens are generally cylindrical in shape, they may also show a significant degree of taper along their length. When printing images onto such pens, the taper may also present problems for accurate reproduction of the image.

If the cylindrical or spherical object has texture, such as the dimples on a golf baIl, this will present further problems for prior art approaches.

Ink jet printing is a technique that is conventionally used to print large, flat images. Examples of images that can be created by ink jet printing are large colour posters and advertising images, e.g. of A4 page size or larger. These techniques involve holding the paper, onto which the ink jet printer is to print, under the ink jet printing head.

The inventors have seen writing on electrical cable that appears to have been produced by ink jet printing. However, the inventors are not aware of any details of how such ink jet printing has been implemented. It might, for example, have been achieved by printing using a conventional ink jet printer whilst the cable insulation was still flat, and then forming the insulation into a cylinder. The ink jet printing might have been implemented on a layer of material that was then wrapped around the cable insulation. Alternatively, the cable might have been compressed during the printing process, in order to present a quasi-flat surface.

The inventors are aware of an oral disclosure, i.e. industry rumours, that at least one major manufacturer has attempted to devise a way of ink jet printing onto cylindrical objects, but that this attempt was unsuccessful. The inventors are therefore unaware of any enabling disclosure, which would permit ink jet printing on either cylindrical or spherical objects.

Summary of Invention

In accordance with a first aspect of the invention, there is provided an ink jet printer in accordance with claim 1.

In accordance with a second aspect of the invention, there is provided a method of ink jet printing in accordance with claim 4.

In accordance with a third aspect of the invention, there is provided an ink jet printer in accordance with claim 7.

In accordance with a fourth aspect of the invention, there is provided a method of ink jet printing in accordance with claim 10.

In accordance with a fifth aspect of the invention, there is provided a method of manufacturing an ink jet printer in accordance with claim 13.

The appended dependent claims provide details of further preferred features of embodiments of the invention.

Embodiments of the invention involve ink jet printing onto cylindrical or spherical objects. However, in the context of embodiments of the invention, it is envisaged that these terms should be interpreted broadly. For example, it is within the contemplation of the invention that these terms include objects with surface texture, such as dimples or concave regions. The term cylindrical also includes geometrical shapes that are generally cylindrical, such as cigar shaped' objects or objects of circular cross section that taper in one direction.

The term spherical also encompasses broadly spherical objects with non-uniform radius of curvature, e.g. ovoid objects, and objects with cylindrical areas, such as the top of a conical section of a sphere. Both cylindrical and spherical objects may have irregularities, such as steps in their surface or regions that are raised or lowered with respect to the radius of curvature of the remainder of the object.

Embodiments of the invention may provide numerous advantages over the known prior art. Embodiments of the invention may avoid the difficulties associated with creating masks or foils. In particular, embodiments of the invention may avoid the need for various chemicals that are used to create printing masks.

In comparison to prior art arrangements, embodiments of the invention may allow one or more of the following: (i) More accurate printing; (ii) Printing on parts of cylindrical and spherical objects that could not be

reached by prior art arrangements;

(iii) A greater rate of throughput of components; (iv) A reduced set up time when a new image for printing is received.

Brief Description of the Drawincis

Figure 1 shows the general geometrical arrangement of the ink jet printer according to some embodiments of the invention, and a component of cylindrical or spherical shape; Figure 2 expands the two-dimensional view of figure 1 to show a cylindrical component and its central axis; and Figure 3 expands the two-dimensional view of figure 1 to show a spherical component and an axis through its centre.

Description of Embodiments of the Invention

Figure 1 shows the general geometrical arrangement of the ink jet printer, according to embodiments of the invention, for printing an image onto a component 100. Component 100 of figure 1 may be of either cylindrical or spherical shape. Figures 2 and 3 are provided to show more clearly a three dimensional perspective view of cylindrical and spherical objects, respectively, and the location of the axis 130 in either case.

Considering now figure 1, one embodiment of the invention comprises an ink jet printer for printing onto cylindrical component 100, including an ink jet printing head 110. The printing head 110 is adapted to release jets of ink 120 in a first direction D, as illustrated in figure 1.

Component 100 can be rotated, as shown by the arrow towards the lower edge of figure 1. The rotation takes place about a central axis 130. The cylindrical component 100 is arranged with its central axis 130 perpendicular to direction D. The means for rotating a cylindrical component 100 is adapted to rotate the cylindrical component 100 about the central axis 130.

With this arrangement, the cylindrical component can be rotated to present different portions to the jets of ink released from ink jet printing head 120. An image can therefore be built up on the component. High speed and quality can be ensured by arranging for computer control of the rotation.

The ink jet printer may be further adapted whereby ink jet printing head 110 releases coloured jets of ink 120. With such an arrangement, a coloured image can be built up on component 100 without needing the component to be moved to the location of a different printing station. This overcomes the problem of prior art arrangements that use print masks, which require movement of the cylindrical object to a different location for each coloured mask.

The means for rotating a cylindrical component 100 may be adapted to rotate cylindrical component 100 reversibly, as illustrated in figure 1. This speeds up the printing process, enabling a shorter printing time. Where a series of cylindrical objects are to be printed, this may allow a greater rate of throughput of cylindrical objects.

In accordance with the arrangement of figure 1, a method of ink jet printing onto a cylindrical component 100 includes the release of jets of ink 120 in a first direction D, from an ink jet printing head 110. The method also includes the step of rotating a cylindrical component 100 about its central axis 130.

Central axis 130 is perpendicular to the first direction D. The method may optionally further comprise the ink jet printing head 110 releasing coloured jets of ink 120, and rotating the cylindrical component 100 reversibly.

The method of the invention includes a method of manufacturing an ink jet printer for printing onto a cylindrical component 100. The method of manufacture includes providing an ink jet printing head 110, which is adapted to release jets of ink 120 in first direction D. The method of manufacture also includes providing means for rotating the cylindrical component 100 about its central axis 130, whereby the central axis 130 is perpendicular to first direction D. Figure 2 shows an expanded view of the two-dimensional view of figure 1, to provide a three dimensional view of the cylindrical component 200.

Component 200 corresponds to the cylindrical example of component 100 of figure 1. Figure 2 also illustrates central axis 230, which corresponds to the central axis 130 shown in figure 1. Central axis 230 passes through the centre of cylindrical component 200 in its long' direction. Central axis 230 is perpendicular to direction D shown in figure 1.

Figure 3 shows an expanded view of the two-dimensional view of figure 1, to provide a three dimensional view of spherical component 300. Spherical component 300 corresponds to the spherical example of component 100 of figure 1. Figure 3 also illustrates an axis 330, which corresponds to the central axis 130 shown in figure 1. Axis 330 is perpendicular to direction D shown in figure 1. Axis 330 passes through the centre of spherical component 300, as can be seen to be the case for axis 100 in the two-dimensional general arrangement shown in figure 1.

As can be seen in figures 1 and 3, one embodiment of the invention comprises an ink jet printer for printing onto a spherical component 100, 300.

The ink jet printer comprises an ink jet printing head 110 adapted to release jets of ink 120 in a first direction D. Means are provided for rotating the spherical component 100, 300 about an axis 130, 330 through the centre of the spherical component 100, 300. The axis 130, 330 is perpendicular to the first direction D. The ink jet printer of figures 1 and 3 may optionally further comprise the feature of the ink jet printing head 110 being adapted to release coloured jets of ink 120. In addition, the means for rotating the spherical component 100, 300 may be adapted to rotate the spherical component 100, 300 reversibly.

Optimum speed and quality can be ensured by arranging for computer control of the rotation.

In accordance with embodiments of the invention, a method for printing onto a spherical component 100, 300 comprises the ink jet printing head 110 releasing jets of ink 120 in first direction D. The method includes the step of rotating the spherical component 100, 300 about axis 130, 330, which lies through the centre of the spherical component 100, 300. Axis 130, 330 lies perpendicular to the first direction D. Axis 330 can lie in an infinite number of directions, all of which are perpendicular to direction D and pass through the centre of spherical object 300. This contrasts with the axis 230 in figure 2, since the cylindrical object has only one central axis.

The method for printing onto a spherical component 100, 300 may further comprise the step of ink jet printing head 110 releasing coloured jets of ink 120. The method may optionally further include the step of rotating the spherical component 100, 300 reversibly.

Embodiments of the invention may offer one or more significant advantages over known prior art arrangements. These may include one or more of the following: (i) Embodiments of the invention may avoid the disadvantages of painting through masks. These include the inaccuracies introduced by copying an image onto a mask, and the need to handle, store and dispose of the chemicals required to make masks.

(ii) Embodiments of the invention may require less time to set up an image. An image needs only to be converted electronically into the correct format for the ink jet printing head, which contrasts with the time required for the various mechanical steps required to set up a mask. This advantage may contribute to a greater rate of throughput of components.

(iii) Embodiments of the invention may permit printing on parts of cylindrical and spherical objects that could not be reached by prior art arrangements.

This may include the portions of cylindrical or spherical object that lie close to major steps, i.e. changes in surface height, in the object.

(iv) Embodiments of the invention may obviate the need for the component to be moved to different locations for printing with different colours. Such movement with prior art arrangements lead to problems in aligning the different coloured components of an image.

(v) At least two aspects of the invention can be implemented digitally, rather than using analogue arrangements. The first concerns the control of the rotation of the object. For example, a digital stepper motor can be used, under computer control, to provide rotation of the component 100, 200, 300 to any required degree of accuracy. In addition, the control of the ink jets from printer head 110 can be controlled digitally. This provides a more accurately timed release of ink than was possible with prior art arrangements, which relied on forcing ink through a mask.

(vi) The arrangement of embodiments of the invention is robust. The mask of prior art arrangements was, in comparison, fragile. As a consequence, the mask could be damaged by contact with cylindrical or spherical components that were brought into contact with the mask with too much force, or which were not properly aligned in their mountings. Embodiments of the invention do not require direct physical contact between the ink jet printing head 100 and the cylindrical or spherical object. Even if contact were to occur, ink jet printing head 100 is not prone to tearing, as was possible with prior art masks.

(vii) The same ink jet printing head 110 can print on either cylindrical or spherical objects.

(viii) The masks of prior art arrangements tend to wear out after ink has been forced through them onto perhaps 1000-5000 objects. So a new mask is then needed, and this is likely to differ slightly from the first mask. Embodiments of the invention may effectively allow the same image to be printed onto an indefinite numbers of objects, identically, provided that the ink jet head is maintained and cleaned adequately.

It will be appreciated that, for clarity purposes, the above description has described embodiments of the invention with reference to different functional units. However, it will be apparent that any suitable distribution of functionality between different functional units, processors or domains may be used without detracting from the invention. For example, functionality illustrated to -10-be performed by separate processors or controllers to control aspects of the printing process may be performed by the same processor or controller.

Hence, references to specific functional units are only to be seen as references to suitable means for providing the described functionality, rather than indicative of a strict logical or physical structure or organization.

Aspects of the invention may be implemented in any suitable form including hardware, software, firmware or any combination of these. Aspects of the invention may optionally be implemented, at least partly, as computer software running on one or more data processors and/or digital signal processors.

Thus, the elements and components of an embodiment of the invention may be physically, functionally and logically implemented in any suitable way.

Indeed, the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units.

Although the invention has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the present invention is limited only by the claims. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined in accordance with the invention.

Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by, for example, a single unit or processor.

Additionally, although individual features may be included in different claims, these may possibly be advantageously combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. Also, the inclusion of a feature in one category of claims does not imply a limitation to this category, but rather the feature may be equally applicable to other claim categories, as appropriate.

Furthermore, the order of features in the claims does not imply any specific order in which the features must be performed and in particular the order of individual steps in a method claim does not imply that the steps must be performed in this order. Rather, the steps may be performed in any suitable order. In addition, singular references do not exclude a plurality. Thus, references to ca', an', first', second', etc. do not preclude a plurality. -12-

Claims

Claims 1. An ink jet printer for printing onto a cylindrical component

(100, 200), comprising: an ink jet printing head (110), the printing head (110) adapted to release jets of ink (120) in a first direction (D); means for rotating a cylindrical component (100, 200), the cylindrical component (100, 200) having a central axis (130, 230); whereby the cylindrical component (100, 200) is arranged with the central axis (130, 230) perpendicular to the said first direction (D); and the means for rotating a cylindrical component (100, 200) is adapted to rotate the cylindrical component (100, 200) about the central axis (130, 230).
2. The ink jet printer of claim 1, further comprising: the ink jet printing head (110) being adapted to release coloured jets of ink (120).
3. The ink jet printer of claim I or claim 2, further comprising: the means for rotating a cylindrical component (100, 200) being adapted to rotate the cylindrical component (100, 200) reversibly.
4. A method of ink jet printing onto a cylindrical component (100, 200), corn prisi ng: an ink jet printing head (110) releasing jets of ink (120) in a first direction (D); rotating a cylindrical component (100, 200) about its central axis (130, 230), whereby the said central axis (130, 230) is perpendicular to the said first direction (D).
5. A method of ink jet printing according to claim 4, further comprising: the ink jet printing head (110) releasing coloured jets of ink (120).
6. A method of ink jet printing according to claim 4 or claim 5, further corn p rising: rotating the cylindrical component (100, 200) reversibly.
7. An ink jet printer for printing onto a spherical component (100, 300), comprising: an ink jet printing head (110), the printing head (110) adapted to release jets of ink (120) in a first direction (D); means for rotating a spherical component (100, 300); whereby the means for rotating the spherical component (100, 300) are arranged to rotate the spherical component (100, 300) about an axis (130, 330) through the centre of the spherical component (100, 300), the said axis (130, 330) being perpendicular to the said first direction (D).
8. The ink jet printer of claim 7, further comprising: the ink jet printing head (110) being adapted to release coloured jets of ink (120). -14-
9. The ink jet printer of claim 7 or claim 8, further comprising: the means for rotating the spherical component (100, 300) being adapted to rotate the spherical component (100, 300) reversibly.
10. A method of ink jet printing onto a spherical component (100, 300), comprising: an ink jet printing head (110) releasing jets of ink (120) in a first direction (D); rotating a spherical component (100, 300) about an axis (130, 330) through the centre of the spherical component (100, 300), the said axis (130, 330) being perpendicular to the said first direction (D).
11. A method of ink jet printing according to claim 10, further corn prisi ng: the ink jet printing head (110) releasing coloured jets of ink (120).
12. A method of ink jet printing according to claim 10 or claim 11, further comprising: rotating the spherical component (100, 300) reversibly.
13. A method of manufacturing an ink jet printer for printing onto a cylindrical component (100, 200), comprising: providing an ink jet printing head (110) adapted to release jets of ink (120) in a first direction (D); providing means for rotating a cylindrical component (100, 200) about its central axis (130, 230), whereby the said central axis (130, 230) is perpendicular to the said first direction (D).