JP2007076343A - Printing device, printing method, and printing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing device, a printing method, and a printing program which can fully use the ability of the printing device while achieving balance between the generation speed and printing speed of print data. <P>SOLUTION: When a printer controller 14 receives image data from a host 12, a data conversion unit 16 converts the image data into print data corresponding to a printing process performed by a printing unit 32. The print data are compressed by a compressing unit 18 and stored in a storage unit 20. An expansion unit 22 reads the print data from the storage unit 20 and stores them in a print data storage unit 24 while expanding it. An engine control unit 26 detects the data amount of the print data stored in the print data storage unit 24 and determines the printing speed of the printing unit 32 based on the detected data amount. The engine control unit 26 controls the operation of a print control unit 30 and a paper transporting speed control unit 28 and causes the print unit 32 to execute the printing process at the determined printing speed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a printing apparatus, a printing method, and a printing program that can optimize a printing speed.

  Conventionally, a technique for balancing the generation speed of image data to print data corresponding to print processing and the print speed has been proposed.

For example, Patent Document 1 below discloses a technique for determining the printing speed of a page in accordance with the band area where the print data generation speed is lowest in each band area within one page.
Japanese Patent Laid-Open No. 11-115278

  However, each band region may have a complex image and may take time to convert to print data, or may be simple and not take time to convert to print data. For this reason, there is a bias in print data generation speed between the band areas. However, in the above conventional technique, the print speed is determined for each page. Printing is performed at the same printing speed as the band area where the data generation speed is slow. For this reason, there is a problem that the page cannot be printed with the maximum capability of the printing apparatus.

  On the other hand, in order to maximize the capability of the printing apparatus, it is necessary to increase the capability of the print data generation processing unit, which increases the cost of the apparatus.

  Further, it is conceivable that the printing process is performed regardless of the generation speed of the printing data, and the printing process is temporarily stopped when there is no printing data. However, in this case, it is necessary to accurately feed and stop the paper, and for that purpose, the paper conveyance speed cannot be increased sufficiently, and the capacity of the printing apparatus cannot be maximized. .

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a printing apparatus, a printing method, and a printing apparatus that can make full use of the capabilities of the printing apparatus while balancing the print data generation speed and the print speed To provide a printing program.

  In order to achieve the above object, the present invention provides a printing apparatus, comprising: conversion means for converting image data into print data corresponding to print processing; storage means for storing the print data; and storage means Data amount detecting means for detecting the data amount of the stored print data, and speed determining means for determining a print speed based on the detected data amount are provided.

  Here, the speed determining means sets an upper limit threshold and a lower limit threshold for the detected data amount, determines a constant printing speed when the detected data amount is between the upper limit threshold and the lower limit threshold, and detects the detection When the data amount is not less than the upper limit threshold or not more than the lower limit threshold, the printing speed is changed based on the data amount.

  The speed determining means sets a lower limit threshold for the detected data amount, determines a constant printing speed when the detected data amount exceeds the lower limit threshold, and the detected data amount is less than or equal to the lower limit threshold. In some cases, the printing speed is changed based on the data amount.

  In addition, the present invention is a printing apparatus, wherein the image data is converted into print data corresponding to print processing for each predetermined area, and the compression means for compressing the print data for each predetermined area. And a speed determining means for determining a printing speed at the time of the compression processing of the compressing means.

  The printing apparatus includes: a compressed data storage unit that stores the compressed print data; an expansion unit that reads the compressed print data from the compressed data storage unit and expands the print data; and A speed prediction unit that predicts a decompression speed by the decompression unit during compression processing, and the speed determination unit changes the printing speed based on the decompression speed.

  The present invention is also a printing method, the step of converting image data into print data corresponding to print processing, the step of storing the print data, and the step of detecting the data amount of the stored print data And a step of determining a printing speed based on the detected data amount.

  Further, the present invention is a printing method, comprising: converting image data into print data corresponding to print processing for each predetermined area; compressing the print data for each predetermined area; And a step of determining a printing speed during the compression process.

  The present invention is also a printing program for converting image data into print data corresponding to print processing, storing the print data, detecting a data amount of the stored print data, and detecting the detected data amount. The computer is caused to execute processing for determining a printing speed based on the above.

  The present invention is also a printing program, which converts image data into print data corresponding to print processing for each predetermined area, compresses the print data for each predetermined area, and performs the compression process. The computer is caused to execute processing for determining the printing speed.

  Hereinafter, the best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described with reference to the drawings.

Embodiment 1. FIG.
FIG. 1 shows a block diagram of a configuration example of a printing apparatus according to the first embodiment of the present invention. In FIG. 1, a printing apparatus 10 receives image data from a host 12 and prints it on a predetermined sheet. The printing apparatus 10 includes a printer controller 14, a data conversion unit 16, a compression unit 18, a storage unit 20, a decompression unit 22, a print data storage unit 24, an engine control unit 26, a paper conveyance speed control unit 28, a print control unit 30, A printing unit 32, an image forming unit 34, and a paper transport unit 36 are included.

  The printer controller 14 is a central control device that controls the printing operation of the image data received from the host 12 by the printing device 10, and includes a data conversion unit 16 and a compression unit 18.

  The data converter 16 is included in the printer controller 14 and converts the image data received from the host 12 into print data corresponding to print processing by the printer 32. This print data is, for example, bitmap data.

  The compression unit 18 is included in the printer controller 14 and compresses the print data generated by the data conversion unit 16.

  The storage unit 20 is a computer-readable storage medium including, for example, a CPU working RAM, a magnetic storage medium, and the like, and stores data such as print data compressed by the compression unit 18 and a program.

  The decompression unit 22 reads the compressed print data from the storage unit 20 and stores it in the print data storage unit 24 while decompressing.

  The print data storage unit 24 includes a first-in first-out (FIFO) memory that performs first-in first-out processing, and stores the expanded print data. Note that the print data generated by the conversion process of the data conversion unit 16 may be directly stored in the print data storage unit 24. In this case, the compression unit 18 and the expansion unit 22 are not necessary.

  The engine control unit 26 controls the printing process in the printing unit 32 of the printing data stored in the printing data storage unit 24. In this case, the engine control unit 26 detects the data amount of the print data stored in the print data storage unit 24, and determines the print speed of the print unit 32 based on this data amount. This printing speed is determined, for example, as the length of the paper printed per unit time, that is, the paper transport speed during printing. This determination method will be described with reference to FIG. The engine control unit 26 controls the operations of the print control unit 30 and the paper transport speed control unit 28 based on the determined printing speed. Here, the engine control unit 26 functions as a data amount detection unit and a speed determination unit of the present invention.

  The paper transport speed control unit 28 controls the paper transport speed of the paper transport unit 36 provided in the printing unit 32 based on the paper transport speed determined by the engine control unit 26.

  The print control unit 30 generates a print timing pulse for the print unit 32 based on an instruction from the engine control unit 26 and causes the print data stored in the print data storage unit 24 to be printed. This print timing pulse is generated in response to a paper transport speed instruction from the paper transport speed control unit 28.

  The printing unit 32 includes an image forming unit 34 and a paper transport unit 36, and prints the print data stored in the print data storage unit 24 based on instructions from the paper transport speed control unit 28 and the print control unit 30. To form an image.

  The image forming unit 34 is configured by, for example, an ink jet printing apparatus, and forms an image on the paper from the print data in accordance with a print timing pulse from the print control unit 30. The image forming unit 34 is not limited to the above-described ink jet system. For example, the photosensitive drum, the optical writing system that exposes the photosensitive drum, the developing system that develops the exposed photosensitive drum with toner, and the developed image on paper It may be a printing apparatus constituted by a fixing system or the like for fixing to the printer.

  The paper transport unit 36 performs an operation of sending printing paper to the image forming unit 34 at a transport speed instructed by the paper transport speed control unit 28.

  According to the above configuration, since the printing speed is sequentially changed according to the data amount of the print data stored in the print data storage unit 24, a slow printing speed is obtained for a complex image on the same page. In the case of a simple image, the printing process is executed at a high printing speed. For this reason, even if there is a bias in the print data generation speed on the same page, printing can be performed at a speed corresponding to the conversion speed to the print data, and the printing capability of the printing unit 32 should be used to the maximum. Can do.

  The engine control unit 26 sets an upper limit threshold and a lower limit threshold for the detected data amount, determines a constant printing speed when the detected data amount is between the upper limit threshold and the lower limit threshold, and the detected data amount is the upper limit threshold. When it is above or below the lower threshold, the printing speed may be changed based on the data amount.

  Alternatively, a lower limit threshold is set for the detected data amount, and when the detected data amount exceeds the lower limit threshold, a constant printing speed, for example, the upper limit speed of the printing unit 32 is determined, and the detected data amount is equal to or lower than the lower limit threshold. Sometimes, the printing speed may be changed based on the data amount.

  With the above configuration, when the conversion speed to the print data frequently fluctuates in the data converter 16, it is possible to avoid the printing speed frequently fluctuating and the operation of the printing apparatus becoming unstable.

  FIG. 2 is an explanatory diagram of a method for determining the printing speed by the engine control unit 26. In FIG. 2, the horizontal axis represents the elapsed time of the printing process, and the vertical axis represents the paper conveyance speed. If the paper size is constant, the amount of data printed per fixed length in the paper sub-scanning direction (paper feeding direction) is constant. Therefore, if the paper transport speed is determined, the printing speed is determined. It will be.

  Here, V0 shown in FIG. 2 is the current sheet conveyance speed. V1 is the maximum possible sheet conveyance speed at that time calculated based on the data amount of the print data stored at a certain point in the print data storage unit 24. “a” or “−a” is an acceleration at the time of acceleration / deceleration, that is, a change amount of the sheet conveyance speed per unit time. tu is the time required for the paper conveyance speed to transition from V0 to V1 at an acceleration a. Su is the amount of data printed during the tu. td is the time required from when the paper transport speed reaches V1 to decelerate at the acceleration −a and stop the paper transport. Sd is the amount of data to be printed during the time td, and is the minimum amount of data that should be secured when the paper transport speed reaches V1. If the data amount is less than Sd, a so-called underrun occurs in which the data amount prepared in the print data storage unit 24 is not in time for the print speed in the print unit 32. To be precise, the amount of data to be printed is proportional to the areas Su and Sd, and it is necessary to multiply this by a proportionality constant, but the proportionality constant is set to 1 for simplicity.

  For example, when the amount of data stored in the print data storage unit 24 is (Su + Sd), the printing speed is increased at the acceleration a while printing from the current paper transport speed V0 to V1, and the paper transport speed reaches V1. When the sheet is decelerated at the acceleration −a and the sheet conveyance is stopped, the amount of data stored in the print data storage unit 24 and the amount of data printed during the time tu + td are balanced. Further, when the sheet conveyance speed reaches V1, if the amount of data stored in the print data storage unit 24 is equal to or greater than Sd, the speed V1 can be maintained. This is because, if the data amount is greater than or equal to Sd, the amount of data that is necessary when the print speed is reduced to 0 at acceleration −a is exceeded, so that an underrun can be avoided.

  Note that the printing unit 32 is configured to be able to perform printing while following the paper conveyance speed at that time while the current paper conveyance speed transits from V0 to V1 and from V1 to 0. .

  Therefore, when the data amount of the print data stored in the print data storage unit 24 increases to (Su + Sd) during the printing process at the paper conveyance speed V0, the upper limit V1 of the print speed that can be set is expressed by the following equation: Can be calculated.

  Su = V0 * tu + 1/2 * tu * (V1-V0) (1)

  Sd = 1/2 × td × V1 (2)

  V1 = a × tu + V0 (3)

  V1-a * td = 0 (4)

Here, from the above (1) and (2), the data amount S of the print data storage unit 24 is
S = Su + Sd = 1/2 * tu * V0 + 1/2 * (tu + td) * V1 (5)
When V1 is obtained by substituting tu = 1 / a × (V1−V0) and td = V1 / a obtained from (3) and (4) into tu and td in (5) above, V1 = [(2aS + V0 × 2) / 2] ^0.5 (6)
It becomes.

  In the example of FIG. 2, the value of the acceleration a is constant for the sake of simplification, but may be arbitrarily changed during the printing process.

  As described above, the engine control unit 26 can determine the print speed based on the amount of data stored in the print data storage unit 24.

  FIG. 3 shows a flow of an operation example of the printing apparatus according to the present embodiment. In FIG. 3, when the printer controller 14 receives image data to be printed from the host 12 (S1), the data conversion unit 16 converts the image data into print data corresponding to the printing process by the printing unit 32 (S2). .

  The print data generated by the data conversion unit 16 is compressed by the compression unit 18, the compressed print data is temporarily stored in the storage unit 20, and the decompression unit 22 stores the compressed print data in the storage unit 20. Are stored in the print data storage unit 24 while being expanded (S3). If the storage capacity of the print data storage unit 24 is large, the print data generated by the data conversion unit 16 may be stored directly in the print data storage unit 24 without being compressed.

  The engine control unit 26 detects the amount of print data stored in the print data storage unit 24 (S4). Next, the engine control unit 26 determines the printing speed of the printing unit 32 as shown in FIG. 2 based on the detected data amount (S5). Further, the engine control unit 26 controls the operations of the print control unit 30 and the paper conveyance speed control unit 28 based on the determined printing speed, and the image data acquired from the host 12 at the printing unit 32 determined above. Is executed (S6).

  According to the above configuration, the data amount of the print data stored in the print data storage unit 24 can be detected, and the print speed of the print unit 32 can be flexibly changed according to this data amount even during printing of the same page. . Thereby, the capability of the printing apparatus can be used to the maximum while balancing the print data generation speed and the print speed.

Embodiment 2. FIG.
FIG. 4 is a block diagram showing a configuration example of Embodiment 2 of the printing apparatus according to the present invention. The same components as those in FIG. In FIG. 4, image data received from the host is converted into print data by the data conversion unit 16 for each band obtained by dividing one page into a predetermined length, compressed by the compression unit 18, and stored in the storage unit 20. The The reason why the image data is processed for each band is due to the limitation of the memory capacity of the print data storage unit 24. Here, the storage unit 20 functions as a compressed data storage unit of the present invention. The compressed data stored in the storage unit 20 is stored in the print data storage unit 24 while being expanded for each band by the expansion unit 22, and is printed by the printing unit 32 under the control of the engine control unit 26.

  In the present embodiment, a characteristic point is that when the print data is compressed by the compression unit 18, the printer controller 14 predicts the expansion speed of the corresponding band in the expansion unit 22, and based on the predicted expansion speed. The point is to determine the printing speed of the corresponding band. For example, when the extension process is performed at the predicted extension speed, the print speed for completing the band print process is determined in the time required for the band extension process. The printer controller 14 in this case corresponds to the speed prediction means and speed determination means of the present invention. In this way, when printing of the corresponding band is started, the printer controller 14 further calculates the predicted expansion time and printing speed of the next band. Based on the determined printing speed, the printer controller 14 instructs the engine control unit 26 to print the corresponding band. The engine control unit 26 instructs the paper conveyance speed control unit 28 and the print control unit 30 based on the printing speed to control the printing process of the printing unit 32. The printing process for the page may be started after the calculation for one page is completed.

  The process in which the printer controller 14 predicts the decompression speed in the decompression unit 22 is performed by obtaining the correlation actual value of the decompression time in the decompression unit 22 from the compressed data amount, the compression time, the employed compression algorithm, etc. It is executed by a method such as calculating a predicted value of time.

  5 and 6 are explanatory diagrams showing examples of processing in which the printer controller 14 determines the print speed of the band. In these drawings, the horizontal axis represents the print elapsed time, and the vertical axis represents the print speed. Here, the image data for one page is divided into three bands. V1, V2, and V3 are printing speeds in the bands 1, 2, and 3 calculated by the printer controller 14, respectively. Vm is the upper limit of the printing speed in the printing unit 32. t1, t2, and t3 are times required to expand each band. Note that values obtained by dividing the data amount of each corresponding band by t1, t2, and t3 are V1, V2, and V3.

In FIG. 5, the value determined by the printer controller 14 as the printing speed of the band 1 exceeds the upper limit Vm of the printing speed of the printing unit 32. This is a case where the capability of the expansion unit 22 exceeds the capability of the printing unit 32. V2 and V3 are lower than Vm. In this case, when band 1 is printed at Vm, as shown in FIG. 6, after the printing time t1, only the data amount S1 is printed and remains. Therefore, in order to print the print data corresponding to the data amount S1, printing at the printing speed Vm is extended by Δt1. If the amount of data printed during the extended Δt1 is S1 ′, S1 = S1 ′.
(V1−Vm) × t1 = Vm × Δt1 (7)
It becomes.

Next, in band 2, it takes time (t2) required for decompression, and the decompression speed (the decompressed data generation amount per unit time) is slower than that in band 1, so the printing process is performed at a printing speed lower than the printing speed of band 1. There is a need. Here, the printing process is performed while decreasing the printing speed at a predetermined deceleration a (acceleration -a) from Vm to V2. In this deceleration area, printing is performed by S2 more than when printing at the printing speed V2. Accordingly, the printing time is reduced by Δt2. If the amount of data that will be printed during Δt2 is S2 ′, then S2 = S2 ′.
(Vm−V2) ² / 2a = V2 × Δt2 (8)
It becomes.

Furthermore, since the extension speed of band 3 is faster than that of band 2, the printing process can be performed at a printing speed higher than the printing speed of band 2. Here, the printing process is performed while increasing the printing speed at a predetermined acceleration a from V2 to V3. In this acceleration area, printing is performed by S3 less than when printing at the printing speed V3. Accordingly, the printing time is extended by Δt3 accordingly. If the amount of data printed during Δt3 is S3 ′, then S3 = S3 ′.
(V3−V2) ² / 2a = V3 × Δt3 (9)
It becomes.

  The printer controller 14 calculates the printing speeds V1, V2, V3 and the printing times in the respective bands 1, 2, 3 based on the above formulas (7), (8), (9).

  In the present embodiment, the print data storage unit 24 has a storage capacity that does not hinder each band expansion process and the print process, and the expansion unit 22 performs the print data expansion process at an appropriate timing. Was described as performing. Further, the determination process of the printing speed by the printer controller 14 is not limited to the example of FIGS. 5 and 6, and any method that does not break the balance between the expansion process and the printing process can be employed.

  FIG. 7 shows a flow of an operation example of the printing apparatus according to the present embodiment. In FIG. 7, when the printer controller 14 receives image data to be printed from the host 12 (S11), the data conversion unit 16 converts the image data into print data corresponding to print processing by the printing unit 32 for each band. (S12).

  The print data generated by the data conversion unit 16 is compressed by the compression unit 18, and the compressed print data is stored in the storage unit 20 (S13). During this compression process, the printer controller 14 predicts the expansion speed of each band by the expansion unit 22 (S14).

  The printer controller 14 determines the print speed of the corresponding band based on the expansion speed predicted in S14 (S15).

  Further, the printer controller 14 issues a print instruction to the engine control unit 26 based on the determined print speed. The engine control unit 26 controls the operations of the print control unit 30 and the paper transport speed control unit 28 based on the instructed print speed, and the image data acquired from the host 12 at the print speed instructed to the print unit 32. Is executed (S16).

  According to the above configuration, the expansion speed of each band by the expansion unit 22 can be predicted, and the printing speed of the printing unit 32 can be flexibly changed even during printing of the same page according to the expansion speed. Thereby, the capability of the printing apparatus can be used to the maximum while balancing the print data generation speed and the print speed.

1 is a block diagram of a configuration example of a printing apparatus according to a first embodiment of the present invention. It is explanatory drawing of the determination method of the printing speed by the engine control part shown by FIG. FIG. 6 is a flowchart of an operation example of the printing apparatus according to the first embodiment. It is a block diagram of the structural example of the printing apparatus concerning Embodiment 2 of this invention. FIG. 5 is an explanatory diagram illustrating an example of processing in which the printer controller illustrated in FIG. 4 determines a band printing speed. FIG. 5 is an explanatory diagram illustrating an example of processing in which the printer controller illustrated in FIG. 4 determines a band printing speed. FIG. 9 is a flowchart of an operation example of the printing apparatus according to the second embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Printing apparatus, 12 Host, 14 Printer controller, 16 Data conversion part, 18 Compression part, 20 Storage part, 22 Expansion part, 24 Print data storage part, 26 Engine control part, 28 Paper conveyance speed control part, 30 Print control part , 32 printing section, 34 image forming section, 36 paper transport section.

Claims (9)

Conversion means for converting image data into print data corresponding to print processing;
Storage means for storing the print data;
Data amount detection means for detecting the amount of print data stored in the storage means;
Speed determining means for determining a printing speed based on the detected data amount;
A printing apparatus comprising:   The printing apparatus according to claim 1, wherein the speed determining unit sets an upper limit threshold and a lower limit threshold for the detected data amount, and a constant printing speed when the detected data amount is between the upper limit threshold and the lower limit threshold. And the printing speed is changed based on the data amount when the detected data amount is equal to or greater than the upper limit threshold value or equal to or less than the lower limit threshold value.   The printing apparatus according to claim 1, wherein the speed determining unit sets a lower limit threshold value for the detected data amount, determines a constant printing speed when the detected data amount exceeds the lower limit threshold value, and detects the detected data. When the amount is equal to or less than the lower limit threshold, the printing speed is changed based on the data amount. Conversion means for converting image data into print data corresponding to print processing for each predetermined area;
Compression means for compressing the print data for each of the predetermined areas;
Speed determining means for determining a printing speed at the time of compression processing of the compression means;
A printing apparatus comprising:   5. The printing apparatus according to claim 4, wherein compressed data storage means for storing the compressed print data, decompression means for reading the compressed print data from the compressed data storage means, and decompressing the compressed print data; and the compression means And a speed prediction unit that predicts a decompression speed by the decompression unit, and the speed determination unit changes the print speed based on the decompression speed. Converting image data into print data corresponding to print processing;
Storing the print data;
Detecting a data amount of the stored print data;
Determining a printing speed based on the detected data amount;
A printing method comprising: Converting image data into print data corresponding to print processing for each predetermined area;
Compressing the print data for each of the predetermined areas;
Determining a printing speed during the compression process;
A printing method comprising: Convert image data into print data corresponding to print processing,
Storing the print data;
Detecting the data amount of the stored print data,
A printing program that causes a computer to execute a process of determining a printing speed based on the detected data amount. The image data is converted into print data corresponding to print processing for each predetermined area,
Compress the print data for each predetermined area,
A printing program for causing a computer to execute a process for determining a printing speed during the compression process.

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