Printing apparatus, printing method, and printing program

Abstract

To provide a printing apparatus that enables highly accurate prediction of the processing time for rasterization. [Solution] The printing apparatus of the present invention includes a control unit 10 that performs rasterization on the PDL data to be printed to generate bitmap data when a print job is executed. Before executing a print job, the control unit 10 performs a preliminary rasterization on the PDL data at a second resolution lower than the first resolution used during actual printing. Based on the processing time taken for the preliminary rasterization, the magnification relationship between the first and second resolutions, and the configuration information of each individual object present in the PDL data, the control unit 10 is configured to predict the actual rasterization time during printing.

Description

Technical Field

[0001] The present disclosure relates to a printing apparatus, a printing method, and a printing program.

Background Art

[0002] Conventionally, in a printing apparatus, a process of generating bitmap data by performing rasterization processing on PDL (Page Description Language) data described in a page description language transferred from a host computer has been performed. And in the printing apparatus, printing is performed by outputting the bitmap data to a printing unit. For example, refer to Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, the processing time required for rasterization processing varies depending on the number of pages of the entire manuscript to be printed, the manuscript size, the number of objects in each page, and the occupancy rate of the CPU or processor core related to the processing. Therefore, this processing time ranges from a few seconds for short ones to several hours in some cases, which affects the entire printing process. Hereinafter, the processing time required for rasterization processing is referred to as "rasterization time".

[0005] If this rasterization time can be predicted in advance, it becomes possible to consider the order of the printing process or, in the case of label machines, to use it as an indicator of waiting time for continuous printing, thereby improving production efficiency.

[0006] Against this backdrop, various methods for predicting rasterization time are being considered. For example, in recent years, methods have been explored that involve rasterizing PDL data at a low resolution before the actual rasterization process, and then predicting the actual rasterization time based on the time required during that process. However, with conventional technologies, it is difficult to accurately predict rasterization time, and currently, customers are unable to plan their printing processes accordingly.

[0007] This invention has been made in view of the above-mentioned problems. Specifically, the object of this invention is to provide a printing apparatus, a printing method, and a printing program that can predict the processing time of rasterization with high accuracy. [Means for solving the problem]

[0008] The main present invention that solves the aforementioned problems is: The system includes a control unit that, when executing a print job, performs rasterization on the PDL data to be printed to generate bitmap data. Before executing the print job, the control unit performs a preliminary rasterization process on the PDL data at a second resolution lower than the first resolution used during actual printing. This printing apparatus is configured to predict the actual rasterization time during printing based on the processing time taken for the provisional rasterization process, the magnification relationship between the first resolution and the second resolution, and the configuration information of each individual object present in the PDL data.

[0009] Also, in other situations, A printing method for a printing device, which, when executing a print job, performs a rasterization process on the PDL data to be printed to generate bitmap data, and then performs printing based on the bitmap data, Before executing the print job, a step is taken to perform a provisional rasterization process on the PDL data at a second resolution lower than the first resolution that will be executed in the actual print process. A step of predicting the actual rasterization time during printing based on the processing time taken for the provisional rasterization process, the magnification relationship between the first resolution and the second resolution, and the configuration information of each individual object present in the PDL data. This is a printing method that has [a certain characteristic].

[0010] Also, in other situations, A printing program for a printing device that, when executing a print job, performs a rasterization process on the PDL data to be printed to generate bitmap data, and then performs printing based on that bitmap data, Before executing the print job, a step is taken to perform a provisional rasterization process on the PDL data at a second resolution lower than the first resolution that will be executed in the actual print process. A step of predicting the actual rasterization time during printing based on the processing time taken for the provisional rasterization process, the magnification relationship between the first resolution and the second resolution, and the configuration information of each individual object present in the PDL data. It is a printing program that has [a certain feature]. [Effects of the Invention]

[0011] According to the printing apparatus of the present invention, it is possible to predict the processing time of rasterization with high accuracy. [Brief explanation of the drawing]

[0012] [Figure 1] A diagram showing the configuration of the printing system according to the first embodiment. [Figure 2] A diagram showing the configuration of a printing apparatus according to the first embodiment. [Figure 3] Figure showing the flow of rasterization processing during printing in a printing apparatus according to the first embodiment [Figure 4] Diagram schematically showing the prediction processing of rasterization time performed by the control unit of the printing apparatus according to the first embodiment [Figure 5] Diagram showing an example of a correction magnification table referred to by the control unit of the printing apparatus according to the first embodiment during the prediction processing of rasterization time [Figure 6] (Example 1) Diagram schematically showing the calculation process of the predicted value of rasterization time [Figure 7] (Example 2) Diagram schematically showing the calculation process of the predicted value of rasterization time [Figure 8] (Example 2) Diagram showing the configuration of the correction magnification table [Figure 9] Diagram schematically showing the preliminary rasterization processing in the control unit of the printing apparatus according to the second embodiment [Figure 10] Diagram showing an example of a data table for setting the resolution used by the control unit of the printing apparatus according to the second embodiment for preliminary rasterization processing [Figure 11] Diagram showing an example of the operation flow of the control unit of the printing apparatus according to the second embodiment [Figure 12] Diagram showing the problems that occur when, in a printing apparatus according to the prior art, the rasterization processing of PDL data and the printing processing of an image converted into bitmap data by the rasterization processing are executed simultaneously in parallel [Figure 13] Diagram showing an example of the print plan generation processing performed by the control unit of the printing apparatus according to the third embodiment

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments to which the present invention is applied will be described in detail based on the drawings. In this specification and the drawings, elements having substantially the same function or configuration are denoted by the same reference numerals, and redundant descriptions are omitted.

[0014] <Configuration of the Printing System> First, the configuration of a printing system according to one embodiment of the present invention (hereinafter referred to as "Printing System A") will be explained with reference to Figure 1.

[0015] Figure 1 shows the configuration of printing system A.

[0016] Printing system A is configured, for example, with a printing device 1 and an external device 2. Each of the devices, printing device 1 and external device 2, is connected via a communication network such as a LAN to enable data communication.

[0017] The printing device 1 is a so-called MFP (Multi-Function Peripheral) equipped with copying, image reading, and printing functions. For example, this printing device 1 may be a tandem-type image processing device that has a photosensitive drum for each CMYK color and transports paper and prints simultaneously with image formation on the photosensitive drum. Alternatively, the printing device 1 may be an image processing device that forms monochrome images using only a single-color photosensitive drum. The printing device 1 forms an image on paper based on print job data transmitted from an external device 2.

[0018] External device 2 is, for example, a host computer (hereinafter referred to as host PC) and has the function of sending print job data to printing device 1. A printer driver is installed on external device 2. Using the functions of this printer driver, external device 2 generates print job data including data on printing conditions applied during image formation and sends it to printing device 1.

[0019] Print job data is PDL data in page description languages ​​such as PS, PCL, PDF, and XPS (hereinafter referred to as PDL data).

[0020] Furthermore, the printing apparatus 1 according to this embodiment is configured to perform a preliminary rasterization process on the PDL data so that the processing time required to rasterize the PDL data can be predicted in advance. Figure 1 shows how the printing apparatus 1 sends back the total processing time required to rasterize all pages of the PDL data contained in the original document of the received print job data to the external device 2 as a predicted rasterization time.

[0021] Figure 2 shows the configuration of the printing device 1.

[0022] The printing device 1 comprises a control unit 10, a storage unit 11, an operation unit 12, a display unit 13, an image reading unit 14, a printing unit 15, and a communication unit 16, and each unit is electrically connected by a bus.

[0023] The control unit 10 is, for example, a microcontroller equipped with a CPU 10a, ROM 10b, and RAM 10c. The control unit 10 reads a program corresponding to the processing content from ROM 10b, loads it into RAM 10c, and works in cooperation with the loaded program to centrally control the operation of the printing unit 15, etc. At this time, various data stored in the storage unit 11 are referenced. The storage unit 11 is composed of, for example, a non-volatile semiconductor memory (so-called flash memory) or a hard disk drive.

[0024] The control unit 10 transmits and receives various types of data to and from an external device 2 connected to a communication network such as a LAN or WAN via the communication unit 16. For example, the control unit 10 receives print job data transmitted from the external device 2 and executes printing on the recording medium based on this print job data.

[0025] During image formation processing, the control unit 10 analyzes the print job data (PDL data) received from the external device 2 and generates data in intermediate language (Display List) format (hereinafter also referred to as display list). Then, rasterization processing is performed based on the display list to generate bitmap data as print data (hereinafter also referred to as bitmap data). The generated bitmap data is then output to the printing unit 15.

[0026] The memory unit 11 stores lookup tables (LUTs) used for image processing, and correction multiplier tables D1 that the control unit 10 refers to when predicting rasterization time.

[0027] The operation unit 12 has various keys such as number keys, a start key, and a reset key, and outputs a press signal of the pressed key to the control unit 10. The operation unit 12 also has a touch panel integrally formed with the display unit 13, and detects the position on the touch panel when the user's fingertip or stylus is in contact with it, and outputs a position signal to the control unit 10.

[0028] The display unit 13 consists of an LCD or the like, which is covered by a touch panel, and displays various setting screens for inputting various setting conditions, various processing results, etc., according to the display signals input from the control unit 10.

[0029] The image reading unit 14 is a so-called scanner that reads an image of a document and generates image data. It includes a platen glass on which the document is placed, and a scanning optical system that scans the image of the document on the platen glass and forms an image on a CCD image sensor. The image reading unit 14 generates an image signal by performing A / D conversion on the image signal generated based on the document image read by the CCD image sensor.

[0030] The printing unit 15 is a functional unit that includes components necessary for forming an image using an imaging process such as electrophotography, electrostatic recording, or thermal transfer. For example, the printing unit 15 includes an exposure unit, a developing unit, an image forming unit having a photoreceptor drum, a fixing unit, a paper feeding unit, a transport unit, a paper discharge unit, a drive control device, etc. The printing unit 15 forms an image on paper supplied from the paper feeding unit and transports it to the paper discharge unit based on image data generated by the image reading unit 14 or print job data received by the communication unit 16, in accordance with instructions from the control unit 10.

[0031] The communication unit 16 is equipped with a LAN adapter, router, TA, etc., and transmits and receives data with external devices such as external device 2 connected via the communication network 3. For example, the communication unit 16 receives PLD data from external device 2.

[0032] <Basic Rasterization Processes> Next, the basic rasterization process performed by the control unit 10 will be explained.

[0033] Figure 3 is a simplified diagram illustrating the flow of the rasterization process during printing.

[0034] The control unit 10 acquires the PDL data transmitted from the external device 2 via the communication unit 16 and temporarily stores the acquired PDL data in the RAM 10c (step S1).

[0035] The control unit 10 reads the PDL data from the RAM 10c and performs language analysis processing (step S2). In the language analysis processing, the read PDL data for one page is divided into multiple line bands, and a display list of the language format between the PDL data and the bitmap data is generated for each of these divided bands. The control unit 10 temporarily stores the generated display list in the RAM 10c.

[0036] A display list is data generated according to the characteristics of the objects (text data, graphics data, image data, etc.) contained in the PDL data. For example, a display list for text data or graphic data can be in vector format, while a display list for image data can be in image format.

[0037] When the display list for one page is completed, the control unit 10 reads the display list from RAM 10c and performs rendering based on the read display list (step S3). During the rendering process, bitmap data divided into band units is generated and sequentially stored in RAM 10c. At this time, the control unit 10 converts the object data of each object stored in the display list into bitmap data, one by one, on a band-by-band basis.

[0038] When the bitmap data for one page is completed, the control unit 10 reads the bitmap data from the RAM 10c, outputs the bitmap data to the printing unit 15, and starts the printing unit 15 to perform the printing process (step S4). Then, the printing unit 15 forms an image on the paper based on the input bitmap data.

[0039] Furthermore, the processes in steps S2 to S3 shown in Figure 3 (language analysis and rendering) are generally divided into bands or pages by multiple CPU cores and processed in parallel using multitasking.

[0040] <Prediction process for rasterization time> The control unit 10 according to this embodiment has the function of performing the following first to fourth steps on the PDL data received from the external device 2 and predicting in advance the rasterization time required for the actual rasterization process.

[0041] Figure 4 schematically shows the rasterization time prediction process performed by the control unit 10. Figure 5 shows an example of the correction magnification table D1 that the control unit 10 refers to during the rasterization time prediction process.

[0042] The actual rasterization time is the sum of the time spent on language analysis and the time spent on rendering. However, language analysis time is shorter than rendering time, and language analysis is generally performed in parallel with rendering. Therefore, here we will ignore language analysis time and treat rendering time as the rasterization time.

[0043] [1st step] In the first step, the control unit 10 performs a preliminary rasterization process (hereinafter referred to as "preliminary rasterization") on the received PDL data at a resolution lower than the resolution used during the actual rasterization process. Typically, the control unit 10 performs this preliminary rasterization process on a page-by-page basis. Here, the resolution used during the actual rasterization process (hereinafter referred to as "first resolution") is, for example, 1200 dpi. The resolution used during the preliminary rasterization process (hereinafter referred to as "second resolution") is, for example, 150 dpi. However, the values ​​of the first and second resolutions are appropriately varied depending on the content of the printing process.

[0044] The preliminary rasterization process itself is the same as normal rasterization, sequentially performing language analysis and rendering on the PDL data. During this process, the control unit 10 measures the rendering time. The control unit 10 then stores the time taken for rendering (i.e., rasterization time) in RAM 10c.

[0045] Furthermore, if the document to be printed spans multiple pages, the control unit 10 performs a preliminary rasterization process on the PDL data of each page, measures the rasterization time, and stores the rasterization time taken for each page in the RAM 10c.

[0046] Furthermore, the appropriate resolution (i.e., the second resolution) used when performing the preliminary rasterization process in the first step may be set based on the configuration of objects present in the PDL data (see the second embodiment described later).

[0047] [Second process] In the second step, the control unit 10 extracts configuration information for each individual object contained in the PDL data. Typically, the control unit 10 extracts the object configuration information on a page-by-page basis. Since PDL data usually has an object-based data structure, no special processing is required for the process of extracting object configuration information from it.

[0048] Here, the composition of an object refers to, for example, the types and number of objects present on a page. Examples of object types include image data (including photographic data and embedded illustration data; the same applies hereafter), graphic data, and text data.

[0049] In the second step, it is particularly desirable for the control unit 10 to extract the number of pixels for each image data present on the page and to extract the total number of pixels. This is because, as will be described later, the total number of pixels for the image data present on the page has a particularly large impact on the rasterization time. However, from the viewpoint of improving the accuracy of rasterization time prediction, the control unit 10 may also extract the total number of shapes defined by the graphic data present on the page and the total number of texts defined by the text data present on the page.

[0050] Furthermore, if the document to be printed spans multiple pages, the control unit 10 extracts object configuration information from the PDL data of each page and stores it in RAM 10c for each page.

[0051] [3rd step] In the third step, the control unit 10 refers to the correction multiplier table D1 previously stored in the storage unit 11 to obtain a correction multiplier (hereinafter abbreviated as the correction multiplier) for converting the processing time taken in the provisional rasterization process of the first step into the actual rasterization time.

[0052] The Correction Magnification Table D1 is data that defines the correction magnification, for example, by taking the magnification relationship between the first and second resolutions and the object configuration as input variables. In Figure 5, an example of the Correction Magnification Table D1 provides two magnification relationships between the first and second resolutions: 150 dpi (second resolution) / 1200 dpi (first resolution) and 150 dpi (second resolution) / 600 dpi (first resolution). The Correction Magnification Table D1 then defines the correction magnification for each magnification relationship, which is based on the total number of pixels in the image data of objects present in one page of PDL data.

[0053] Furthermore, the correction magnification table D1 is determined, for example, through prior validation (experiments or simulations). However, since it is difficult to obtain experimental data for all preconditions, the correction magnification table D1 may be prepared in the form of a regression equation or similar that can calculate output values ​​according to the input explanatory variable (for example, the total number of pixels in the image data) based on the experimental data.

[0054] Generally, when rasterizing data at a high resolution, the number of bands generated when dividing a single page of PDL data into multiple lines also increases, which in turn prolongs the rasterization time. Therefore, when converting the processing time taken during the preliminary rasterization process to the actual rasterization time, a correction process is necessary that takes into account the magnification relationship between the first and second resolutions.

[0055] However, according to the inventors of this application, when rasterization is performed at a low resolution, the structure of the object is more likely to be lost than it actually is, and the correction magnification required depending on the structure of the object tends to fluctuate. In other words, correction processing that relies solely on the resolution during the preliminary rasterization process, as considered in the prior art, and corrects the processing time taken during the preliminary rasterization process, cannot be expected to have sufficient accuracy in the predicted value of the calculated rasterization time.

[0056] From this perspective, the correction magnification table D1 according to this embodiment defines a correction magnification that takes the magnification relationship between the first resolution and the second resolution and the configuration of the object as input variables.

[0057] According to the inventors' diligent research, rendering time (i.e., rasterization time) depends particularly on the total number of pixels in the image data present on the page. That is, the influence of the number of images in the image data, as well as text data and graphic data, is small compared to the total number of pixels in the image data. From this perspective, in the correction magnification table D1 according to this embodiment, the total number of pixels in the image data present on the page is used as the input variable for the object configuration.

[0058] The correction magnification plot shown in Figure 5 is based on the rasterization time obtained through actual pre-verification for each input variable condition. In Figure 5, the correction magnification decreases as the total number of pixels in the image data increases, which is presumably because the provisional rasterization processing time obtained when rasterizing at a low resolution itself becomes longer as the total number of pixels in the image data increases.

[0059] However, in addition to the total number of pixels in the image data present on the page, the total number of shapes defined by the graphic data present on the page, and the total number of text elements defined by the text data present on the page may also be used as input variables to construct the correction magnification table D1. This makes it possible to further improve the accuracy of predicting the rasterization time.

[0060] Furthermore, if the document to be printed spans multiple pages, the control unit 10 obtains the correction multiplier to be applied to each page based on the object configuration of the PDL data for each page and stores it in the RAM 10c.

[0061] [4th step] In the fourth step, the control unit 10 corrects the processing time taken for the preliminary rasterization process using the correction factor obtained in the third step. The control unit 10 performs this correction by, for example, multiplying the correction factor obtained in the third step by the processing time taken for the preliminary rasterization process obtained in the first step.

[0062] Furthermore, if the document to be printed spans multiple pages, the control unit 10 corrects the rasterization time obtained in the first step (the processing time taken for the preliminary rasterization process) for each page using the correction magnification obtained in the third step.

[0063] The control unit 10 stores the obtained predicted rasterization time in the RAM 10c and transmits data related to the predicted rasterization time to the external device 2. At this time, the control unit 10 may, for example, transmit to the external device 2 the total processing time required to rasterize the PDL data for all pages contained in the original document of the received print job data as the predicted rasterization time, as shown in equation (1) below.

[0064] Predicted rasterization time for print job data = (Estimated rasterization time × Correction factor based on object configuration) ... Total for all pages ... Equation (1)

[0065] Furthermore, the control unit 10 may perform the following adjustments from the viewpoint of improving the accuracy of the predicted rasterization time.

[0066] If image correction settings (e.g., color conversion, color bar, contour processing) are set in the print job settings, the control unit 10 may add an adjustment margin to the predicted rasterization time based on the content of the image correction settings. For example, if monochrome settings are set in the print job settings, the actual rasterization time will be shorter than when outputting in color. Therefore, the control unit 10 may adjust the predicted rasterization time calculated above by multiplying it by a predetermined amount, for example, according to the content of the image correction settings.

[0067] Furthermore, the control unit 10 may calculate a predicted rasterization time by taking into account the language analysis time in addition to the rendering time. However, since the language analysis process is generally executed in parallel with the rendering process, in this case it is sufficient to consider only the language analysis time for the first page. For example, the control unit 10 may add the language analysis time for the first page to the predicted rasterization time calculated in equation (1) above to obtain a predicted rasterization time for the print job data.

[0068] Furthermore, the control unit 10 may calculate a predicted rasterization time, taking into account the document size specified in the PDL data. This is because the number of division bands in the rasterization process changes depending on the document size, and consequently, the rasterization time also changes. In this case, it is desirable to prepare a correction magnification table D1 for each document size, for example.

[0069] Furthermore, the control unit 10 may calculate a predicted rasterization time taking into account the data format of the PDL data. This is because the rasterization time may differ depending on whether the PDL data is written in PCL format, PDF format, or XPS format. In this case, it is desirable to prepare a correction magnification table D1 for each data format of the PDL data, for example.

[0070] Next, we will describe a specific example of the function for calculating predicted rasterization time.

[0071] <Example 1> In this embodiment, we will describe a method for calculating the predicted rasterization time of a one-page document (PDL data) composed of multiple image data.

[0072] Figure 6 schematically shows the calculation process for the predicted rasterization time in Example 1. In this example, the correction magnification table D1 is assumed to be the one shown in Figure 5.

[0073] First, the control unit 10 performs a preliminary rasterization process on the PDL data received from the external device 2 at a second resolution (here, 150 dpi), which is lower than the first resolution (here, 1200 dpi) used during actual printing. The rasterization time taken at this time is measured (here, 100 seconds) and stored in RAM 10c (first step). At this time, the control unit 10 can obtain the original size and the number of bands (here, the number of bands in the preliminary rasterization process). In this case, the original size was 210 x 297 mm and the number of bands in the preliminary rasterization process was 3.

[0074] Next, the control unit 10 obtains object configuration information from the PDL data received from the external device 2 (second step). In this embodiment, there were three images, and the total number of pixels for all images was 26,000 pixels (3,000 + 3,000 + 20,000).

[0075] Next, the control unit 10 refers to the correction magnification table D1 and obtains a correction magnification for correcting the predicted rasterization time based on the configuration information of each object in the PDL data and the magnification relationship between the first resolution and the second resolution (third step). In this embodiment, the control unit 10 refers to the correction magnification table D1 shown in Figure 5 and obtains 2.0 as the correction magnification.

[0076] Next, the control unit 10 corrects the rasterization time at low resolution obtained in the first step using the correction magnification obtained in the third step (fourth step). In this embodiment, the predicted value of the rasterization time is calculated to be 200 seconds from the processing time of 100 seconds for the provisional rasterization process multiplied by the correction magnification magnification of 2.0.

[0077] <Example 2> In this embodiment, we will describe a method for calculating the predicted rasterization time of a one-page document (PDL data) composed of multiple image data and text data.

[0078] Figure 7 schematically shows the calculation process for the predicted rasterization time in this embodiment. Figure 8 shows the configuration of the correction magnification table D1 referenced in this embodiment. The correction magnification table D1 referenced in this embodiment defines the correction magnification using the magnification relationship between the first resolution and the second resolution, the total number of pixels in the image data, and the total number of text characters defined by the text data as input variables. In Figure 8, for the sake of explanation, only the tables for the cases where the total number of pixels in the image data is 12,000 pixels, 16,000 pixels, and 20,000 pixels are shown.

[0079] The content of the first step is the same as in Example 1. Here, the rasterization time obtained in the first step is assumed to be 100 seconds. Note that the rasterization time obtained in the first step of this example is the same as the rasterization time obtained in the first step of Example 1. This is because text data has a low rasterization load and therefore has little impact on the rasterization time. Also, in the temporary rasterization process performed at a low resolution second resolution (150 dpi in this case), differences in rasterization time depending on the object's structure are less likely to occur.

[0080] In the subsequent second step, the control unit 10 acquires configuration information for each individual object included in the PDL data. At this time, it was analyzed that there are three images with a total of 16,000 pixels, and that there are 50,000 text characters.

[0081] In the subsequent third step, the control unit 10 obtains a correction magnification corresponding to these input variables (the magnification relationship between the first and second resolutions, the total number of pixels in the image data, and the number of texts) from the correction magnification table D1. Here, the control unit 10 obtained a correction magnification of 1.8x from the correction magnification table D1.

[0082] In the subsequent fourth step, the control unit 10 multiplies the processing time of 100 seconds taken for the preliminary rasterization process by a correction factor of 1.8. This allows us to predict that the actual rasterization time will be 180 seconds (= 100 seconds × 1.8).

[0083] [effect] As described above, in this embodiment, The system includes a control unit that, when executing a print job, performs rasterization on the PDL data to be printed to generate bitmap data. Before executing the print job, the control unit performs a preliminary rasterization process on the PDL data at a second resolution lower than the first resolution used during actual printing. A printing apparatus is disclosed that is configured to predict the actual rasterization time during printing based on the processing time taken for the provisional rasterization process, the magnification relationship between the first resolution and the second resolution, and the configuration information of each individual object present in the PDL data.

[0084] According to the printing apparatus of this embodiment, it is possible to predict the processing time of the rasterization process with high accuracy.

[0085] (Second embodiment) In the above embodiment, the resolution during the preliminary rasterization process (i.e., the second resolution) was set to a fixed value (150 dpi), but in this embodiment, the resolution is set variably.

[0086] Typically, the first step, preliminary rasterization, is faster the fewer output bands there are. Since the number of bands depends on the original size and resolution, reducing the resolution is necessary to speed up processing. However, reducing the resolution too much reduces the number of actual samples (= number of samples for band processing time), which risks lowering the reliability of the predicted rasterization time.

[0087] Therefore, the control unit 10 according to this embodiment extracts the configuration information of objects present in the PDL data to be printed before performing the first step of the preliminary rasterization process. Then, based on the configuration information of those objects, it sets the resolution for the preliminary rasterization process.

[0088] Figure 9 is a schematic diagram showing the temporary rasterization process in the control unit 10 according to this embodiment. Figure 10 is a diagram showing an example of a data table for setting the resolution used for the temporary rasterization process.

[0089] In the case of Figure 9, the document contains only a small amount of text data (for example, a letter). It has been found that with this configuration, the rasterization time is almost the same as for a blank document. In such cases, it is useful to further reduce the resolution during the preliminary rasterization process to decrease the number of output bands and speed up the processing time.

[0090] Therefore, in this embodiment, the control unit 10 sets the resolution during the first step of the preliminary rasterization process to 100 dpi and reduces the number of bands during the preliminary rasterization process to 2.

[0091] Conversely, if the object structure in the PDL data to be printed is complex and the rasterization time is likely to be significantly affected by the object structure, the resolution may be increased to 300 dpi or higher to increase the number of output bands. This allows for obtaining a predicted value of the actual rasterization time under conditions that more closely resemble the actual rasterization process.

[0092] From this perspective, the resolution setting data table shown in Figure 10 has a table structure that increases the resolution used for the preliminary rasterization process as the total number of pixels in the image data present on the page increases.

[0093] Furthermore, in this embodiment, the second step described in the above embodiment may be made common with this step in order to extract the configuration information of objects present in the PDL data to be printed before performing the first step of temporary rasterization.

[0094] Figure 11 shows an example of the operation flow of the control unit 10 according to this embodiment.

[0095] First, the control unit 10 receives PDL data of the document to be printed from the external device 2 (S11). Next, the control unit 10 extracts the configuration information of each individual object contained in the PDL data (S12). Next, the control unit 10 refers to the resolution setting data table and sets the resolution (second resolution) to be used for the preliminary rasterization process based on the configuration information of each individual object contained in the PDL data (S13). Next, the control unit 10 performs the preliminary rasterization process at the resolution set in S13, measures the rasterization time at that time, and stores it in RAM 10c (S14). Next, the control unit 10 refers to the correction magnification table D1 and obtains the correction magnification based on the magnification relationship between the resolution (second resolution) set in S13 and the resolution (first resolution) to be used during actual printing, and the object configuration information obtained in S12 (S15). Next, the control unit 10 calculates a predicted value for the actual rasterization time by multiplying the processing time taken for the preliminary rasterization process by the correction magnification factor obtained in S15 (S16).

[0096] As described above, the printing apparatus 1 according to this embodiment makes it possible to shorten the processing time when calculating the predicted value of the rasterization time required during actual printing.

[0097] (Third embodiment) In the above embodiment, the rasterization time for the entire document to be printed in the print job is predicted based on the predicted rasterization time of the PDL data for each page. In this embodiment, the control unit 10 further calculates a print plan for when the print job is executed based on the predicted rasterization time of the PDL data for each page.

[0098] Figure 12 illustrates the problems that arise when a conventional printing apparatus simultaneously and in parallel performs the rasterization of PDL data and the printing of the image converted to bitmap data by the rasterization process. This figure specifically shows the problems that occur when a roll-type printing press is used. It should be noted that various methods for simultaneously and in parallelly performing the rasterization of PDL data and the printing of images have been considered from the perspective of improving the overall efficiency of the printing process.

[0099] In the upper part of Figure 12, the roll machine prints the original image of page 1, page 2, page 3, ... up to page N onto the roll paper P, starting from the front end. The lower part of Figure 12 schematically shows the completion time of the rasterization process for each page, along with the timing of the roll paper P being transported. In this configuration, the process of printing the original image of page 1 after rasterization is performed, printing the original image of page 2 after rasterization is performed, and so on, is repeated.

[0100] A roll paper press is generally configured with a paper feed unit, an image forming unit, and a winding unit connected from the upstream side along the transport direction of the roll paper P. The roll paper P is sequentially fed from the paper feed unit, an image is formed in the image forming unit, and the roll paper is wound up in the winding unit. For an example of the configuration of a roll paper press, please refer to, for example, Patent Document 2.

[0101] In this type of roll-printing machine, it is generally difficult to stop the transport of the roll paper P midway through, and the transport and image formation must be performed sequentially in sync. Therefore, if the rasterization process takes a long time on any page of the original document (for example, page 3 in Figure 12), and the printing of the original image lags behind the transport speed, a blank area will be formed on the roll paper P during that time. Since the roll paper P is often subsequently cut page by page, such blank areas can become a major problem for the user.

[0102] Given this background, conventional printing methods using roll-based presses have involved completing the rasterization process for all PDL data pages in the document beforehand, before starting the printing process. However, this waiting time constitutes downtime, which can lead to decreased productivity for users.

[0103] Therefore, in the printing apparatus 1 according to this embodiment, the rasterization time required for the PDL data of each page in the document is predicted in advance, and a printing plan for the print data of the document is generated based on the rasterization time required for the PDL data of each page. For example, the control unit 10 starts the printing process of the document at an intermediate stage before the rasterization process of the PDL data of each page in the document is completed, taking into account the total time required for subsequent rasterization.

[0104] Figure 13 shows an example of the print plan generation process of the control unit 10 according to this embodiment.

[0105] First, the control unit 10 calculates the printing start timing for each page based on the transport speed of the roll paper P (S21). Next, the control unit 10 arranges the predicted rasterization times for each page in the document in order from the first page to the Nth page (the last page), and calculates the rasterization completion timing for each page (S22). Next, the control unit 10 places the printing start timing and the rasterization completion timing for each page on the same time axis. Then, the control unit 10 determines the printing start timing (i.e., waiting time) relative to the rasterization start timing so that the rasterization completion timing for each page does not lag behind the printing start timing for each page (S23).

[0106] During actual printing, the print plan generated by this process is used to start printing the document at an intermediate stage before the rasterization of the PDL data for all pages of the document is completed. In this case, the control unit 10 starts the actual rasterization process, waits for the waiting time calculated in S23 to elapse, and then sequentially executes the printing process.

[0107] As described above, the printing apparatus 1 according to this embodiment makes it possible to improve productivity while preventing blank areas from occurring on the printed roll paper.

[0108] <Variation> Furthermore, the printing apparatus 1 according to this embodiment can utilize the predicted rasterization time in various ways in the process of generating a print plan for the print data of the original document. For example, recent printing apparatuses reduce the time required for rasterization by performing rasterization processing in parallel using multiple cores, thereby achieving faster printing processing times. See, for example, Patent Document 3.

[0109] However, even with such printing equipment, if there are images that require a long time to rasterize, the time it takes to rasterize those images can become a bottleneck, which can still cause waiting times during the printing process.

[0110] In such an image forming apparatus, the printing process can be made more efficient by optimizing the number of pages assigned to each core based on the predicted rasterization time.

[0111] Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. [Industrial applicability]

[0112] According to the printing apparatus of the present invention, it is possible to predict the processing time of rasterization with high accuracy. [Explanation of symbols]

[0113] 1 Printing device 2 External device 10 Control Unit 11 Storage section 12 Control section 13 Display section 14 Image reading unit 15 Printing Department 16 Communications Department A Printing System D1 Correction Magnification Table

Claims

1. The system includes a control unit that, when executing a print job, performs rasterization on the PDL data to be printed to generate bitmap data. Before executing the print job, the control unit performs a preliminary rasterization process on the PDL data at a second resolution lower than the first resolution used during actual printing. A printing apparatus configured to predict the actual rasterization time during printing based on the processing time taken for the provisional rasterization process, the magnification relationship between the first resolution and the second resolution, and the configuration information of each individual object present in the PDL data.

2. The object configuration information that the control unit refers to when predicting the rasterization time includes the total number of pixels of the image data present in the PDL data. The printing apparatus according to claim 1.

3. The object configuration information that the control unit refers to when predicting the rasterization time includes the total number of pixels of the image data present in the PDL data, the total number of shapes defined by the graphic data, and the total number of texts defined by the text data. The printing apparatus according to claim 1.

4. The control unit sets the second resolution value for the provisional rasterization process based on the configuration information of each object present in the PDL data. The printing apparatus according to claim 1.

5. The control unit, when image correction settings are made in the job settings of the print job, Based on the processing time taken for the provisional rasterization process, the magnification relationship between the first and second resolutions, the configuration information of each individual object present in the PDL data, and the contents of the image correction settings, the rasterization time is predicted. The printing apparatus according to claim 1.

6. The control unit performs a preliminary rasterization process on the PDL data on a page-by-page basis, and predicts the rasterization time on a page-by-page basis based on the processing time taken for the preliminary rasterization process, the magnification relationship between the first resolution and the second resolution, and the configuration information of each individual object present in the PDL data for one page. The printing apparatus according to claim 1.

7. The control unit calculates the rasterization time for the entire document to be printed in the print job based on the rasterization time of the PDL data for each page. The printing apparatus according to claim 6.

8. The control unit calculates a print plan for the execution of the print job based on the rasterization time of the PDL data for each page. The printing apparatus according to claim 6.

9. Applied to roll machines The printing apparatus according to claim 1.

10. A printing method for a printing device, which, when executing a print job, performs a rasterization process on the PDL data to be printed to generate bitmap data, and then performs printing based on the bitmap data, Before executing the print job, a step is taken to perform a provisional rasterization process on the PDL data at a second resolution lower than the first resolution executed in the actual print process, A step of predicting the actual rasterization time during printing based on the processing time taken for the provisional rasterization process, the magnification relationship between the first resolution and the second resolution, and the configuration information of each individual object present in the PDL data. A printing method that includes [something].

11. A printing program for a printing device that, when executing a print job, performs a rasterization process on the PDL data to be printed to generate bitmap data, and then performs printing based on that bitmap data, Before executing the print job, a step is taken to perform a provisional rasterization process on the PDL data at a second resolution lower than the first resolution executed in the actual print process, A step of predicting the actual rasterization time during printing based on the processing time taken for the provisional rasterization process, the magnification relationship between the first resolution and the second resolution, and the configuration information of each individual object present in the PDL data. A printing program that has [a certain feature].

Images