WO2015011475A1

WO2015011475A1 - A printhead driver board arrangement for 2 or more printheads

Info

Publication number: WO2015011475A1
Application number: PCT/GB2014/052253
Authority: WO
Inventors: Clive Lawrence Ayling; Edward Philip Duffy
Original assignee: The Technology Partnership Plc
Priority date: 2013-07-23
Filing date: 2014-07-23
Publication date: 2015-01-29
Also published as: GB201313118D0

Abstract

An arrangement of a 'master' electronics printed circuit board assembly for driving a printhead and a 'slave' electronics printed circuit board assembly for driving a second printhead, defined in that the 'master' electronics printed circuit board assembly comprises: a. means for receiving image data and/or timing information relating to the control of a plurality of printheads, b. means for using all or a part of the image data and/or timing information to drive a first printhead at the same rate that it receives print data, and c. means for supplying all or part of the image data and/or timing information as a data stream to a separate 'slave' electronics printed circuit board assembly for driving a second printhead and the 'slave' electronics printed circuit board assembly comprises: a. means for receiving image data and/or timing information relating to the control of just one second printhead, b. means for using the image data and/or timing information to drive a second printhead at the same rate that it receives print data, but c. no means for supplying any of the print data to a separate electronics board for driving any further printheads.

Description

A Printhead Driver Board Arrangement for 2 or more printheads Background

It is usual for a print head to have a driver card that provides the power supplies and electrical signals required by the head. Sometimes a single board is used to supply power and signals to multiple heads however this is only practical if the cables between the heads and the board are long and flexible enough to accommodate the actual physical layout of the heads. An architecture comprising a print controller card and several identical head driver boards is a more flexible option, which allows any physical layout of the heads since the electronics can be arranged so that long flexible cabling can be used between the head driver boards and the print controller card which supplies data and timing clocks to them. Such a head driver board receives inputs of a fire signal (timing clocks to control when the printhead will mark the media) and the image data related to each fire signal. Each head driver board outputs the image data to the printhead at the same rate in which it receives data - clocked through in response to the fire signal. The head driver board is unable to buffer data (allowing fire signals to pass by while waiting for the right time to start sending the data to the head) merely clocking through the image data to the printhead. The timing decision of when to begin sending data to the printhead is made in the print controller card upstream of the head driver board. The print controller card is an electronic printed circuit board assembly that prepares the image data and transmits the image data to the head driver boards at the right time for immediate transmission to the heads for causing the media to be patterned with the image. This is the upstream 'timing decision' mentioned in the paragraph above. For practical reasons it is typical to use a single type of print controller card to drive up to a fixed number of head driver cards - such as up to 8. A print controller card for driving 8 head driver cards will have connectors for connecting to eight cables used to transmit the electrical signals to the head driver cards. It is also typical to make the print controller card adaptable using firmware to be capable of supporting different types of head driver boards and thus different types of printheads. This type of print controller card is often called a 'universal print controller card' due to its ability to drive many types of printheads. For example, to drive 8 printheads of type A the electronics required may be one universal print controller card, 8 cables and 8 head driver cards of type A (to match the type of printhead). Whereas to drive 8 printheads of type B the electronics required would be one universal print controller card, 8 cables and 8 head driver cards of type B (to match the type B printheads). The universal print controller cards in these two cases would be identical in hardware but use different software and firmware.

Kenji Yokota in US patent application US 2010/0073416A1 discusses a standard arrangement in which each Head Driver Card supports one head and does not have any link directly to another Head Driver Card. The Head Control Board described by Yokota is differentiated from the Head Driver Boards in the presently disclosed arrangement in that Yokota's Head Control Boards store image data until the right moment for printing as defined by the synchronisation signals it received and they are only indirectly connected to printheads via head driver boards.

Forrest P. Gauthier and Dimitrije L. Jovic in US patent US 6,290,406 B1 discusses an unusual arrangement in which a Tab' on a network picks off data for an interface board to use to drive a 'print engine'. Although the print engine referred to has some similar function to an inkjet printhead, the arrangement of presently disclosed driver boards is neither similar to that of the Tabs (all of which are identical and do not drive a printhead directly) nor of the interface boards (none of which have a direct link to another interface board). Ryoichi Koizumi, Hideaki Kishida, and Akira Katayama in US patent 5,017,948 discuss a standard way to arrange some of the functional parts of an electronic circuit within a printhead. The 'Head Actuating Portion' of the electronic circuit is linked to neighbouring Head Actuating Portions but each is within the printhead and is not a separate board, nor are they differentiated from each other in the way that our invention, as another point of novelty, differentiates head driver boards into two types.

Paul Raymond Drury and Anirban Lahiri in GB patent application GB 2503943 A discuss the challenges of a 'Head Personality Card' ('HPC') that needs to buffer data for an unpredictable period of time while waiting for the correct moment to print as defined by synchronisation signals. Clearly, the HPC is storing the data until it should be sent to the printhead, which is a function that differentiates it from a Head Driver Board. Furthermore each HPC is identical, and thus the arrangement that they discuss differs from the presently disclosed arrangement in that there is both a different arrangement of electronic functions and a different layout of boards.

Problem to be solved

A universal print controller card has the capability to drive printhead types with widely differing demands. Some printheads have few nozzles and others have many nozzles. Likewise some have a low firing frequency and others a high firing frequency. Also, some printheads require multiple bits of data for each pixel (e.g. to code for how large a drop should be created) and other printheads require only 1 bit of data per pixel. Thus, the capacity of a universal print controller card's electronics (e.g. memory and computing space) is used less or more depending on which printhead type it is using. Printers are manufactured in a commercial environment so cost-saving is an important business driver. The capability of a print controller card costs money so inefficient usage of this capability represents a waste of money. However, despite this, no solution to the inefficiency of a universal print controller card when driving smaller printheads has been invented until now.

Summary statement of the invention

According to the present invention, there is provided an electronics printed circuit board assembly for driving a printhead, the circuit board assembly comprising: a. means for receiving image data and/or timing information relating to the control of a plurality of printheads, and b. means for using all or a part of the image data and/or timing information to drive a first printhead, and c. means for supplying all or part of the image data and/or timing information as a data stream to a separate electronics printed circuit board assembly for driving a second printhead

In simple terms, the invention provides a head driver board that is able to stream a part or all of the data that it receives from its source of data to another head driver board. This enables more printheads to be supplied with correct data without increasing the number of sources of data required. Disclosure of the invention

The invention allows the print controller card's electronics to be used more efficiently:

In the invention the head driver board has a connector that enables it to be linked via a short cable to a 'slave' head driver board. The 'master' head driver board is capable of dividing the data it receives from the print controller card into that portion of the data that it requires and that portion of the data that is required by the 'slave' head driver board. Thus, with a single slave attached to each 'master' head driver board the print controller card is effectively driving twice the number of printheads. For clarity, each printhead may have image data relating to different parts of the image, such as different colour planes if each head is an inkjet printhead supplied with different coloured ink. If the heads in question are small then the print controller card will not be over-loaded and will be being used more efficiently.

As an example: sixteen printheads may be controlled by a print controller card that has eight outputs if eight of the printheads are driven by master head driver boards and eight of the printheads are driven by slave head driver boards. The previous alternative is to use two print controller cards (each with eight outputs). Thus the invention brings a reduction in the number of print controller cards required and achieves a reduction in cost and complexity. The master head driver board may or may not be identical to the slave head driver board.

The slave head driver board may connect to further slave head driver boards. In this case a print controller card with 8 outputs may drive up to 8, 16, 24 or more heads depending on how many slaves are linked. The master head driver board may have the capability to connect to just one slave or to multiple slaves. Such connection may in series, i.e. from master to slave to slave, or may be in parallel, i.e. from master to slave 1 and master to slave 2. A combination of series and parallel connections is also possible.

Brief Description of the Figures

To help explain the invention we provide some figures. Figure 1 is a schematic representation of how to connect 16 printheads with drive electronics without using the invention

Figure 2 is a schematic representation of how to connect 16 printheads with drive electronics using one implementation of the invention. Figure 3 is a schematic representation of how to connect 20 printheads with drive electronics using another preferred embodiment of the invention.

Figure 4 is a schematic representation of how to connect 20 printheads with drive electronics using another preferred embodiment of the invention.

Figure 5 is a schematic representation of how to connect 20 printheads with drive electronics without using head driver boards.

Description of Figure 1

In figure 1 we show how sixteen printheads [5] may be typically connected without using the invention. Two print controller cards [1 ] are required as each supports only eight printheads. The cables [2] between the print controller cards [1 ] and the head driver boards [3] are typically long because they are developed by the printer manufacturer or electronics provider to a specification as needed by the application. The cables [4] between each head driver board [3] and each printhead [5] are often short because they are limited by the requirement to avoid electrical noise sensitivity and the pre-existing requirements of the printhead connection. If may be that the print controller card is ideally-sized in capacity to suit eight printheads. However, if it is capable of driving much larger printheads then the print controller cards are underutilised in this architecture and the invention we disclose will be useful.

Description of Figure 2 In figure 2 we show how sixteen printheads [5] may be connected using a preferred embodiment of the invention. One print controller card [1 ] is required as each supports eight 'master' head driver boards [7]. In this preferred embodiment of the invention each master head driver board [7] is connected via a short cable [8] to a slave head driver board [6]. There are eight short cables [8] shown in this figure. The cables [2] between the print controller card [1 ] and the head driver boards [7] are typically long because they are developed by the printer manufacturer or electronics provider to a specification as needed by the application. The cables [4] between each head driver board (whether master [7] or slave [6]) and each printhead [5] are often short because they are limited by the requirement to avoid electrical noise sensitivity and the pre-existing requirements of the printhead connection. If the print controller card has sufficient capacity to support sixteen printheads then this preferred embodiment clearly has advantages in simplicity and cost over the system shown in figure 1 .

Description of Figure 3

In figure 3 we show how twenty printheads [5] may be connected using a preferred embodiment of the invention. One print controller card [1 ] is required as each supports eight 'master' head driver boards [7]. In this preferred embodiment of the invention each master head driver board [7] is connected via a short cable [8] to a slave head driver board [9]. In addition, each slave head driver board [9] is capable of being connected to another slave head driver board [9]. So that the data is daisy- chained not just once from master to slave but some of it is passed again from slave to slave. There are twelve short cables [8] shown in this figure. The cables [2] between the print controller card [1 ] and the head driver boards [7] are typically long because they are developed by the printer manufacturer or electronics provider to a specification as needed by the application. The cables [4] between each head driver board (whether master [7] or slave [9]) and each printhead [5] are often short because they are limited by the requirement to avoid electrical noise sensitivity and the pre-existing requirements of the printhead connection. If the printer has more than sixteen printheads and the print controller card has sufficient capacity to support the number within the printer, then this preferred embodiment clearly has advantages in simplicity and cost over the system shown in figure 1 .

Description of Figure 4

In figure 4 we show how twenty printheads [5] may be connected using a preferred embodiment of the invention. One print controller card [1 ] is required as each supports eight 'master' head driver boards [7]. In this preferred embodiment of the invention each master head driver board [10] is connected via two short cables [8] to two slave head driver boards [6]. Each slave driver board [6] has only one connection to a master head driver board [10]. So that the data is allocated by the master head driver board [10] to either its own printhead or two the appropriate attached slave head driver board [6]. There are twelve short cables [8] shown in this figure. The cables [2] between the print controller card [1 ] and the head driver boards [10] are typically long because they are developed by the printer manufacturer or electronics provider to a specification as needed by the application. The cables [4] between each head driver board (whether master [10] or slave [6]) and each printhead [5] are often short because they are limited by the requirement to avoid electrical noise sensitivity and the pre-existing requirements of the printhead connection. If the printer has more than sixteen printheads and the print controller card has sufficient capacity to support the number within the printer, then this preferred embodiment clearly has advantages in simplicity and cost over the system shown in figure 1 .

Description of Figure 5

In figure 5 we show another arrangement of electronics for how twenty printheads [5] may be connected without using the invention. One print controller card [1 1 ] is directly connected via twenty short cables [4] to twenty printheads [5]. The printhead manufacturers often require that these cables [4] be short in order to avoid electromagnetic interference and emissions. The physical layout of the printheads in an array may be determined by the size of the printheads and the preferred arrangement for optimum print quality of the final printed media. Thus, the print controller card [1 1 ] must be large enough for its cable connectors to be within reach of the cables [4] from the printheads [5]. This can significantly increase the cost of manufacture of this print controller card [1 1 ]. In order to drive the printhead, without the use of any head driver card, the print controller card [1 1 ] must have the correct electronics and connectors to provide the signals and cable connection defined by the printhead manufacturer. Each printhead manufacturer uses different signals and cables, so this print controller card [1 1 ] is unable to drive different types of printheads.

Claims

1 . An arrangement of a 'master' electronics printed circuit board assembly for driving a printhead and a 'slave' electronics printed circuit board assembly for driving a second printhead, defined in that the 'master' electronics printed circuit board assembly comprises: a. means for receiving image data and/or timing information relating to the control of a plurality of printheads, and

b. means for using all or a part of the image data and/or timing information to drive a first printhead at the same rate that it receives print data, and

c. means for supplying all or part of the image data and/or timing information as a data stream to a separate 'slave' electronics printed circuit board assembly for driving a second printhead and the 'slave' electronics printed circuit board assembly comprises: a. means for receiving image data and/or timing information relating to the control of just one second printhead, and b. means for using the image data and/or timing information to drive a second printhead at the same rate that it receives print data, but c. no means for supplying any of the print data to a separate electronics board for driving any further printheads.

2. The 'master' and 'slave' electronics printed circuit board assembly

arrangement of Claim 1 , where the portion of the data stream that the master electronic printed circuit board assembly re-transmits is sufficient for driving just one additional 'slave' electronics printed circuit board.

3. The 'master' and 'slave' electronics printed circuit board assembly arrangement of Claim 1 , in which the master electronics printed circuit board assembly further comprising means for connecting to two or more 'slave' electronic printed circuit board assemblies.

4. The 'master' and 'slave' electronics printed circuit board assembly arrangement according to any one of the preceding claims, wherein the means for supplying all or part of the image data and/or timing information as a data stream in the master electronics printed circuit board assembly includes one or more outputs for connection to respective additional boards.

The 'master' and 'slave' electronics printed circuit board assembly arrangement according to any one of the preceding claims, wherein the means for receiving image data and/or timing information includes at least one data input.

The 'master' and 'slave' electronics printed circuit board assembly arrangement according to any one of the preceding claims, wherein the means in the master electronics printed circuit board assembly for using the data includes one or more microprocessors and/or one or more field programmable gate arrays but the 'slave' electronics printed circuit board assembly contains neither type of component.