Patent Application
20060192795
The present invention relates generally to printers, and more particularly, to an inkjet or other non-impact type printers capable of printing through carbon copy media.
Ink is typically provided to the printhead by an ink cartridge 16 that is attached to the carriage 14. Depending on the design of the printer 10, the ink cartridge 16 can come in various combinations ranging from a single cartridge for black ink to multiple cartridges for each desired ink color. The ink cartridge 16 may even include the printhead itself. In addition, the ink cartridge 16 may be stationary and separate from the carriage 14.
Different types of inkjet printers emit the droplets of ink in different ways. The two main inkjet technologies currently used by printer manufacturers are thermal bubble and piezoelectric. The thermal bubble method (also known as bubble jet) is used by manufacturers such as Canon and Hewlett Packard.
Inkjet printers have several advantages when compared to other types of printers, and as a result, inkjet printers have become increasingly popular. First, inkjet printers are capable of very high resolutions. Current inkjet printers can emit droplets of ink as small as 2 picoliters. This allows the printhead to produce images with resolutions exceeding 4800 dots per inch (dpi). Also, because the printhead never actually touches the paper when creating an image, inkjet printers are very quiet during operation. Similarly, because the printhead never touches the paper, inkjet printers are very versatile in that they can print on a wide variety of print media. Finally, inkjet printers are affordable to purchase, and affordable to operate. The ink cartridges they use are cheap, easy to replace, and readily available.
Inkjet printers do, however, have certain limitations. Because inkjet printers are non-impact printers, they are not capable of printing through multi-page print media such as carbon copy forms. Multi-page print media is commonly used in many types of recordkeeping, including accounting bills, invoices, and so on, and in any industry where a duplicate or “carbon copy” is required. Typically, in order to print on multi-page print media, an impact printer such as a dot matrix printer is used. This is because an impact printer is needed to exert sufficient force to the media to transfer the printed images and text to underlying layers of the media. A typical dot matrix printer strikes pins or hammers against an ink ribbon to produce dots on the print media. The pins are housed within a printhead, and a carriage moves both the printhead and the ink ribbon back and forth across the print media. Images and text are created by appropriately positioning numerous individual dots on the print media. As the pins strike a top layer of the multi-page print media, the force of the pins also cause corresponding dots to be printed on underlying layers of the print media. As will be understood by those skilled in the art, where the multi-page print media is carbon paper there are thin pages coated with a waxy pigmented coating placed between sheets of paper. The pressure of the pins striking an upper sheet of paper causes transfer of the pigment to a lower sheet of paper.
There is a need for printing high quality documents and for creating duplicate copies of such documents during printing.
According to one aspect of the present invention, a printer is operable to print on a multi-layer print media. The printer includes a non-impact printhead, an impact printhead, and a controller operable to control the non-impact printhead to produce an image on a first layer of the print media and to control the impact printhead to produce a corresponding image on a second layer of the print media.
The following discussion is presented to enable a person skilled in the art to make and use the invention. Various modifications to the preferred embodiment will be readily apparent to those skilled in the art, and the generic principles herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention as defined by the appended claims. Thus, the present invention is not intended to be limited to the embodiment shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.
The dot matrix printhead 54 may be positioned on either side of the inkjet printhead 52 along the carriage mechanism 56, generated by arrows 55 and 57 The carriage mechanism 56 moves both inkjet printhead 52 and dot matrix printhead 54 simultaneously across the print media. Having the printheads 52 and 54 side-by-side along the carriage mechanism 56 allows for several options when printing on multi-layer media. If the printheads 52 and 54 are controlled to print the exact same data simultaneously, then the data of inkjet printhead 52 will be offset from the data of dot matrix printhead 54. The distance between printheads 52 and 54 determines the amount of offset between the data. The printheads 52 and 54 may alternatively be controlled to begin and end printing at slightly different times. This enables the data printed by the dot matrix printhead 54 to be aligned with the output of inkjet printhead 52. For example, assume the dot matrix printhead 54 is positioned next to and to the right of the inkjet printhead 52 in
In another embodiment, one of the printheads (for example inkjet printhead 52) is controlled to first print an entire line of data and then the other printhead (for example dot matrix printhead 54) is controlled to print the same line of data again before advancing the print media. In this way, the data being printed by inkjet printhead 52 on the top layer of the print media is aligned with the data being printed by dot matrix printhead 54 on the underlying layers of the print media.
In a second embodiment, the dot matrix printhead 54 may be positioned either above or below the inkjet printhead 52 relative to the direction of travel of the print media. Arrows 59 and 61 in
In any of the previously described embodiments, the print mechanism 50 may operate in both an inkjet mode and a hybrid inkjet/dot matrix mode. The user is able to select in which mode the print mechanism 50 will operate based on the type of print media being used. If a single-layer medium is used, then the user may select the inkjet mode where the print mechanism 50 utilizes only the inkjet printhead 52. If a multi-layer medium is used, such as when duplicate copies are required, then the user may select the hybrid mode where the print mechanism 50 utilizes both the inkjet printhead 52 and the dot matrix printhead 54.
Because the print mechanism 50 may operate in both an inkjet mode and a hybrid inkjet/dot matrix mode, the print mechanism 50 is compatible with a wide variety of print media. In the inkjet mode, the print mechanism 50 is capable of printing on any print media compatible with an inkjet printer. Typically, this includes a wide variety of single-layer media. In the hybrid mode, the print mechanism 50 is capable of printing on any multi-layer media that is similar in shape to print media compatible with an inkjet printer. As a result, the print mechanism 50 is not restricted to only a certain type of multi-layer media (like a typical dot matrix printer). Furthermore, this reduces the operating costs of a printer including the print mechanism 50 because less costly print media may be used compared to the expensive tractor-feed paper used by typical dot matrix printers.
The print mechanism 50 is also capable of producing higher quality images than a typical dot matrix printer. By utilizing the inkjet printhead 52, the print mechanism 50 is able to produce images with resolutions exceeding 4800 dpi. However, when printing on multi-layer media, this resolution is only realized on the top layer because the dot matrix printhead 54 is used to produce the corresponding image on the underlying layer such as with carbon copy paper. This is typically not an issue because high resolutions are not usually required for carbon copies, and the details of a high resolution image would normally be lost anyway when being transferred to a carbon copy page.
The print mechanism 50 also makes significantly less noise during operation when compared to a typical dot matrix printer. This is because the dot matrix printhead 54 is able to use significantly less force when striking the pins 60 against the print medium. Significantly less force may be used because dot matrix printhead 54 does not use an ink ribbon between the pins 60 (see
There are also various other embodiments of the present invention. The inkjet printhead 52 may be any type of inkjet printhead, including thermal bubble and piezoelectric. Moreover, inkjet printhead 52 may be replaced with any type of non-impact printing device, such as a laser printing assembly for laser printing pages. The concepts and principles described herein are thus not limited to being applied to inkjet printers, but apply to other non-impact type printers as well, such as laser printers. Also, dot matrix printhead 54 may contain any number or arrangement of pins, depending on the desired resolution. Moreover, dot matrix printhead 54 may be replaced with any type of impact printing head because no ink ribbon is needed. Finally, the print mechanism may make varying numbers of passes with the printheads 52 and 54 over the print media, with a greater number of passes generating higher potential resolution of data being printed on the print media. Also, in another embodiment, a retrofit kit including the dot matrix printhead 54 and other required components may be made to allow a user to upgrade an existing inkjet printer to print on multi-layer print media. One skilled in the art will understand suitable control circuitry and modifications to existing control circuitry contained in conventional inkjet printers to control the print mechanism 50 and implement the functionality described for the described embodiments of the present invention.
From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention.
