GB2376331A

GB2376331A - Print device with two local memories

Info

Publication number: GB2376331A
Application number: GB0113565A
Authority: GB
Inventors: Athena Christodoulou; Richard Taylor; Christopher Tofts
Original assignee: Hewlett Packard Co
Current assignee: HP Inc
Priority date: 2001-06-04
Filing date: 2001-06-04
Publication date: 2002-12-11
Also published as: GB0113565D0

Abstract

A print device comprises raster image processor (RIP)/print controller 17, print engine (PE) 19, first memory 21, second memory 23, and switch circuit 25. The switch circuit allows print data to be transferred between the RIP/control module and either of the two memories. Print data can also be transferred between either of the memories and the PE for generating printed output. In a first embodiment, print data is transferred to the first memory 21 (Fig. 3a). When the first memory is almost full, the data input path is switched, so as to allow the print data to be stored on the second memory 23 (Fig. 3b). At this time, data stored in the first memory 21 may be output to the PE 19 (Fig. 3c). In a second embodiment (Fig. 4), print data, e.g. for a template document, input to the first memory is copied to the second memory. A first set of data to be embedded into the template document is then transferred to the first memory; a second set of data can then be transferred to the second memory whilst at the same time, the data from the first memory is output to the PE, thus increasing the print efficiency.

Description

A Print Device and Method of Storing Data in a Print Device This invention relates to a print device and method of storing data in a print device.

The invention also relates to a method of printing a document.

Print devices, often called printers, are commonly used in both domestic and commercial environments to convert print data, generated in a computer system, into hard-copy output. A computer system will generally include one or more application programs, such as a word processor program, from which print data is generated for output to a printer. The print data for a particular print'job'usually comprises a page description language (PDL) file describing the physical content of the printable area, and a job description language (JDL) file for describing attributes of the print job, such as the type of paper to be used, the number of copies to be made, the type of finishing to be applied (e. g. stapled/laminated) and so on. Once a print job is generated by the application program, the print data for that job is applied to a print spooler for output to a print device.

A typical print device will comprise a raster-image processor (RIP) for converting the PDL into a file representing the graphical output, e. g. the dots to be printed on a page.

This processed data is then passed to a print engine (PE) which converts the processed data into the electrical signals required to drive the physical mechanism of the print device, e. g. the drum of a laser printer, or the carriage/ink nozzles of an inkjet printer.

Conventionally, a print device will only receive print data (for a print job) from the print spooler of a computer system once it is free to process the print job. In other words, if the print device is currently processing a print job then other print jobs will have to wait on the print spooler until the current print job has finished. This is particularly disadvantageous in networked print environments, i. e. where a plurality of print devices are connected to one or more computer systems by means of a network, since at the time when the current print job has been completed, the computer network may be busy and so the print data cannot be transferred to the selected print device until

the network traffic is low. The print device will be idle until the print data for the new print job can be transferred. As a further disadvantage, the print spooler may become overloaded with further print jobs whilst the network traffic is high, or if the current print job is being processed by the printer. Clearly, the above problems become more prevalent if the print job being processed is particularly large, or a large number of copies have to be reproduced.

According to one aspect of the present invention, there is provided a method of storing data in a print device, the method comprising: establishing, by means of a switch circuit, a first input path between a print data source and a first memory module of the print device ; transferring print data to the first memory module and monitoring the available storage space of the first memory module; in response to the available storage space reaching a predefined level, causing the switch circuit to switch to a second input path between the print data source and a second memory module of the print device; and transferring print data to the second memory module, the first and second memory modules being capable of outputting stored print data to a print engine of the print device.

By arranging for a switch circuit to transfer print data to a first memory module, and then to a second memory module once the first memory module reaches a particular level in terms of available storage space, print data relating to a plurality of print jobs can be transferred to the print device from a computer system. In this way, the print jobs stored on the memory modules can be processed as soon as a current print job has finished printing. Problems associated with traffic on the connection between the print spooler and the print device do not affect the progress of print jobs already stored on the print device. The print device is used more efficiently, and the likelihood of it being idle whilst print jobs are waiting to be processed is reduced.

The method may further comprise: in response to the available storage space in the first memory module reaching the predefined level, establishing, by means of the switch circuit, a first output path between the first memory module and the print engine; and transferring the print data stored in the first memory module to the print engine. The print data can be transferred from the print data source to the second memory module at

the same time as the print data stored in the first memory module is transferred to the print engine via the first output path.

The method may further comprise: monitoring the available storage space of the second memory module; in response to the available storage space of the second memory module reaching a predefined level, causing the switch circuit to switch back to the first input path; and transferring print data from the print data source to the first memory module. In addition, the method may further comprise: in response to the available storage space in the second memory module reaching the predefined level, causing the switch circuit to switch from the first output path to establish a second output path between the second memory module and the print engine; and transferring the print data in the second memory module to the print engine.

The print data can be transferred from the print data source to the first memory module at the same time as the print data stored in the second memory module is transferred to the print engine via the second output path.

The print data source preferably provides raster image processed (RIP) print data.

The method finds particular application if performed on a print system comprising a plurality of networked printer devices.

According to a second aspect of the invention, there is provided a print device control system comprising: a print data source, first and second memory modules for storing print data for output to a print engine; a switch circuit; and a switch control circuit, wherein the switch circuit is arranged to interconnect the print data source with either of the first or second memory modules via respective first and second input paths in accordance with control signals received from the switch control circuit, the switch control circuit causing the switch circuit to change from the first input path to the second input path, in response to the available storage space in the first memory module reaching a predefined level.

Preferably, the switch circuit is further arranged to interconnect the print engine with either of the first or second memory modules via respective first and second output paths in accordance with control signals received from the switch control circuit. The switch control circuit may also be configured to switch the switch circuit to the first or

second output path only if the memory module associated with that respective output I taL--U VYLLIL LliaL path is no longer receiving print data from the print data source.

The switch control circuit is preferably configured to prevent print data being inputted to either of the first or second memory modules if that respective memory module is outputting data to the print engine. As before, the print data source is preferably a raster image processor (RIP).

According to a third aspect of the invention, there is provided a method of printing a document using a print device, the method comprising: establishing, by means of a switch circuit, a first input path between a print data source and a first memory module of the print device; transferring a set of print data to the first memory module; copying the contents of the first memory module to a second memory module; establishing, by means of the switch circuit, a first output path between the first memory module and a print engine of the print device and transferring the print data to the print engine; and causing the switch circuit to switch to a second output path between the second memory module and transferring the copied set of print data to the print engine.

This method allows a set of print data to be copied between memory modules of the print device such that the print data can be processed for printing much more efficiently.

The invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure I is a block diagram representation of a computer network comprising a plurality of computer systems and print devices;

Figure 2 is a block diagram representation of the components of a print device in accordance with a first embodiment of the invention; Figure 3a-3d are block diagram representations of the various stages of a switch circuit forming part of the print device in Figure 2; and Figure 4 is a block diagram representation of the components of a print device in accordance of a second embodiment of the invention.

Referring to Figure 1, in a first embodiment, a computer network 1 comprises first, second and third computer systems 3,5, 7 connected to first, second, and third print devices 9,11, 13 by means of a network connection 15. Each computer system 3,5, 7 comprises at least one application program capable of generating print data for output to one or more of the print devices 9,11, 13. The print data is output from each application program and stored on a print spooler (not shown) forming part of each computer system 3,5, 7.

Referring now to Figure 2, each of the print devices 9,11, 13 comprises a combined RIP/control module 17, a PE 19, two local memories, namely a first memory 21 and a second memory 23, and a switch circuit 25. The switch circuit 25 allows print data to be transferred between the RIP/control module 17 and either of the first or second memories 21,23 in accordance with an internal switching arrangement. The switch circuit 25 also allows print data to be transferred between either of the first or second memories 21,23 and the PE 19 for generating printed output using the print data, in accordance with the switch circuit's internal switching arrangement. The switch circuit 25 operates under the control of the RIP/control module 17.

With regard to the overall computer network operation, print data relating to individual print jobs will be output from any of the first, second, or third computer systems 3,5, 7 connected to the network connection 15. Indeed, in a complex commercial setup, many print jobs will be outputted over the course of a period of time, each print job comprising print data specifying PDL and JDL data (mentioned above). The print jobs will be stored on a print spooler of each computer system 3,5, 7. In order to maintain

efficiency within the computer network 1, the first and second memories 21,23 are utilised as described below.

In use, the RIP/controller 17 of each print device 9,11, 13 will monitor the available

memory of both the first and second memories 21, 23. Specifically, me memory space which is available for storing print data is monitored by the RIP/control module 17. In an initial state, both memories 21,23 are unused, and a first data input path 29 is established between the RIP/control module 17 and the first memory 21, as shown in Figure 3a. When a print job is sent to a particular one of the print devices 9,11, 13 (bearing in mind that the print job could be sent to a specific printer, or simply to any available printer, depending on the nature of the print job or a user's preference setting) from the appropriate print spooler, the print data for that print job is downloaded over the network connection 15, processed by means of the RIP part of the RIP/control module 17, and stored in the first memory 21. If the print data for the print job is large, it is possible that the first memory 21 may approach a predetermined threshold level (which represents the fact that the first memory 21 is almost full). The RIP/control module 17 will respond to this situation by causing the switch circuit 25 to switch to a second data input path 31 between the RIP/control module 17 and the second memory 23, as shown in Figure 3b. Accordingly, the remainder of the print data for the print job is stored in the second memory 23.

Having stored part of the print data in the first memory 21 and part of the print data in the second memory 23, the print data can thereafter be output to the PE 19 for printing (the print data having already been processed by the RIP part of the RIP/control module 17). To enable this, the switch circuit 25 is configured, by means of the RIP/control module 17, to establish a first data output path 33 between the first memory 21 and the PE 19, as shown in Figure 3c. This print data transfer to the PE 19 can be performed whilst the remainder of the print data for the print job is being passed to the second memory 23 by means of the second data input path 31. Once the print data transfer from the first memory 21 is complete, the RIP/control module 17 causes the switch circuit 25 to switch to a second data output path 35 for allowing the remainder of the print data to be output from the second memory 23 to the PE 19. At this time, the switch circuit 25 switches from the second data input path 31, back to the first data

input path 29 so that the first memory 21 can be used to store further print data, as shown in Figure 3d.

The controller part of the RIP/control module 17 and the switch circuit 25 are configured such that the switching of the switch circuit is performed without any risk of data interference. With the above embodiment, an efficient cross-over configuration is provided such that print data cannot be written onto, say, the first memory 21, at the same time as print data is being read from the first memory to the PE 19. The same consideration applies to the second memory 23.

In the situation where the first and second memories 21,23 become full and new print data cannot be written to either of the first or second memories because the print data already stored on them has not been output to the PE 19, an error message is generated from the RIP/control module 17 and sent to the computer system from which the new print data was sent.

Whilst the above embodiment assumes that one print job is large enough to fill the first memory 21, it will, of course, be appreciated that, by making the memories 21,23 of a suitable capacity, a reasonably large number of complete print jobs can be stored before the switch circuit 25 switches over to the second memory 23. Also, whilst the above embodiment assumes the use of two memories 21,23, it will be appreciated that further memories can be provided. However, the switch circuit 25 will have to be configured appropriately so as to cater for such additional memories. The number of additional memories utilised may also depend on the available space on a printed circuit board of the print device used.

A second embodiment will now be described with regard to Figure 4. In this embodiment, the internal circuitry of each of the first, second, and third print devices 9, 11,13 is similar to that in the first embodiment, with the exception that a"copy link" 37 is provided between the first and second memories 21,23. This modified print device is represented in Figure 4 by the numeral 36. The copy link 37 allows print data stored in one memory to be duplicated in the other memory. This is initiated by a

command from the RIP/controller module 17 by means of new control line 39. An advantageous use of such a modified system will be described below.

In certain practical situations, it is necessary to embed a first set of print data into a

secoriu'set oi'L PJL-*U-I't U'-La.'Ms ar,. second set of print data. As an example, some commercial organisations send clients a general document with some amount of personalisation included. A'template' document will often be provided (e. g. a mailshot) into which will be embedded the name and address of the recipient, as well as their first name after the salutation (e. g.

Dear John). Where a large number of clients are involved, the relevant client data will usually comprise a very long list of print data which will have to be incorporated into the template document on a document-by-document basis. However, use of the print device 36 shown in Figure 4 can make the process much more efficient.

Referring to the print device of Figure 4, print data relating to the template document is first transferred from a print spooler of one of the first, second, or third computer devices 3,5, 7, to the print device 36, where it is stored in the first memory 21 by means of the first data input path 29. In the next step, the contents of the first memory 21 are copied to the second memory 23 by means of the copy link 37. Thus, at this stage, the first and second memories 21,23 store identical copies of the print data relating to the template document.

In the next stage, a first set of client data (i. e. data relating to personal information of a first client) is transferred over the first data input link 29 and is embedded into the template document to form a combined set of document print data. This is then transferred to the PE 19 by means of the switch circuit 25 establishing the first data output link 33. At the same time, the switch circuit 25 switches to the second data input link 31 such that a second set of client data is transferred to become embedded with the print data (representing the template document) stored in the second memory 23. Once the combined set of document print data has been printed via the PE 19, the first output path 33 switches over to the second output path 35 and the next combined set of document print data (for the second client) is outputted to the PE 19. The process then repeats itself for each set of client data.

By using the above system, efficient usage of available print resources is used to print an overall set of print data.

Finally, as will be understood by those skilled in the art, although the above two embodiments assume the use of the PE 19 as an integral part of the print devices 9, 11, 13, it is possible that the print data stored on either memory 21, 23 can be transferred to a different one of the print devices for being output to the PE 19 of that different print device.

Claims

Claims 1. A method of storing data in a print device, the method comprising: establishing, by means of a switch circuit, a first input path between a print data source

ILIOI--IE C) r LC p,- :- A. 4 ch tc% thi-firet and a first memory module of the print device ; transferring print data to the first memory module and monitoring the available storage space of the first memory module; in response to the available storage space reaching a predefined level, causing the switch circuit to switch to a second input path between the print data source and a second memory module of the print device; and transferring print data to the second memory module, the first and second memory modules being capable of outputting stored print data to a print engine of the print device.
2. A method according to claim 1, the method further comprising: in response to the available storage space in the first memory module reaching the predefined level, establishing, by means of the switch circuit, a first output path between the first memory module and the print engine; and transferring the print data stored in the first memory module to the print engine.
3. A method according to claim 2, wherein the print data is transferred from the print data source to the second memory module at the same time as the print data stored in the first memory module is transferred to the print engine via the first output path.
4. A method according to any preceding claim, the method further comprising: monitoring the available storage space of the second memory module; in response to the available storage space of the second memory module reaching a predefined level, causing the switch circuit to switch back to the first input path; and transferring print data from the print data source to the first memory module.
5. A method according to claim 4, the method further comprising: in response to the available storage space in the second memory module reaching the predefined level, causing the switch circuit to switch from the first output path to establish a second output path between the second memory module and the print engine; and transferring the print data in the second memory module to the print engine.

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6. A method according to claim 5, wherein the print data is transferred from the print data source to the first memory module at the same time as the print data stored in the second memory module is transferred to the print engine via the second output path.
7. A method according to any preceding claim, wherein the print data source provides raster image processed (RIP) print data.
8. A method according to any preceding claim, the method being performed on each of a plurality of networked printer devices.
9. A print device control system comprising: a print data source, first and second memory modules for storing print data for output to a print engine; a switch circuit; and a switch control circuit, wherein the switch circuit is arranged to interconnect the print data source with either of the first and second memory modules via respective first and second input paths in accordance with control signals received from the switch control circuit, the switch control circuit causing the switch circuit to change from the first input path to the second input path, in response to the available storage space in the first memory module reaching a predefined level.
10. A print device control system according to claim 9, wherein the switch circuit is further arranged to interconnect the print engine with either of the first or second memory modules via respective first and second output paths in accordance with control signals received from the switch control circuit.
11. A print device control system according to claim 10, wherein the switch control circuit is configured to switch the switch circuit to the first output or the second output path only if the memory module associated with that respective output path is no longer receiving print data from the print data source.
12. A print device control system according to claim 10 or claim 11, wherein the switch control circuit is configured to prevent print data being inputted to either of the

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first and second memory modules if that respective memory module is outputting data to the print engine.
13. A print device control system according to any of claims 9 to 11, wherein the print data source is a raster image processor (RIP).

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14. A method of printing a document using a print device, the method comprising : establishing, by means of a switch circuit, a first input path between a print data source and a first memory module of the print device ; transferring a set of print data to the first memory module ; copying the contents of the first memory module to a second memory module ; establishing, by means of the switch circuit, a first output path between the first memory module and a print engine of the print device, and transferring the print data to the print engine ; and causing the switch circuit to switch to a second output path between the second memory module and transferring the copied set of print data to the print engine.
15. A method of controlling data flow in a print device, substantially as hereinbefore described with reference to the accompanying drawings.
16. A print device control system, constructed and arranged substantially as hereinbefore shown and described with reference to the accompanying drawings.
17. A method of printing a document, substantially as hereinbefore described with reference to the accompanying drawings.