JPH0644014A - Printing device - Google Patents

Abstract

PURPOSE:To predict the size of received data, to change the size of an input buffer based on the predictive result and to improve the utilization efficiency of a memory resource and the efficiency of a printing processing. CONSTITUTION:The input buffer 231 can dynamically be allocated from the free RAM area of RAM 23. Received printing data are discriminated whether they are image data or document data in a byte unit. When received printing data are image data, the input buffer 231 is extended. When the value of a document data counter 232 counting the number of bytes on continuously received document data exceeds a prescribed value, it is considered that there is no input of image data and the input buffer 231 is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus equipped with an input buffer for executing printing based on print data input from an external device and storing the print data.

[0002]

2. Description of the Related Art Generally, a page printer having a general-purpose interface receives print data described in an appropriate page description language from a host computer or the like and fetches the print data in an input buffer on a RAM. Then, the print data is read from the input buffer, interpreted, R
Printing is performed by drawing as image data in a bit map memory on the AM and forming a visible image on the drawing content (image data).

By the way, in many cases, the transmission speed of print data from the host computer is much faster than the printing speed. Therefore, the printer's input buffer fills up as soon as it receives data from the host computer. Then, the printer makes the printer busy with respect to the host computer, and requests the host computer to suspend the print data transmission. Then, the data in the input buffer is sequentially processed, and when a certain amount of free space is formed in the input buffer, the printer notifies the host computer that the printer is in the ready state, and prompts restart of print data transmission. The printer repeats this to receive and print data.

Therefore, if the printer has a large input buffer, a large amount of data can be quickly captured. In particular, when the host computer operates on an O / S that performs single task processing and does not have a print spool function, it is desirable for the host computer that the printer captures data quickly. This is because the printer interprets the data,
This is because the next new processing can be performed while the printing processing is continued.

The size of the above-mentioned input buffer is uniquely fixed in the conventional printer. Although there are some which can set the size of the input buffer by a panel switch or a command, when a fixed value is set there, the process is performed with the fixed value thereafter.

[0006]

If the size of the input buffer is larger than the data size, the printer can immediately fetch all the data without being in a busy state. As mentioned above, it is good for the host computer to finish data acquisition quickly.

However, the fact that the input buffer is large means that the capacity used for other purposes is reduced among the limited memory resources. If the print data transmitted from the host computer is small, even if the input buffer is small, the waiting time for the host computer to complete the data transmission is short, and therefore there is not much advantage in having a large buffer. Therefore, in such a case, securing a large input buffer in the printer results in waste of memory resources.

In many printers, the size of the input buffer cannot be changed, and at the time of designing, an appropriate size of the input buffer is determined in consideration of the above points. Also, in some high-performance printers, the size of the input buffer can be changed by an input buffer size setting command from the host computer or panel operation. However, in order to effectively use the function, the user has to send an input buffer size setting command or perform a panel operation each time printing is performed.

The present invention has been made in view of the above problems, and makes it possible to predict the size of received data, change the size of the input buffer based on the prediction result, and use memory resources. An object of the present invention is to provide a printing apparatus that improves the efficiency and the efficiency of print processing.

[0010]

A printer according to the present invention for achieving the above object has the following configuration. That is, in a printing device that performs printing based on print data received from an external device, a storage unit that temporarily stores the received data in an input buffer, a prediction unit that predicts the size of the print data, and the prediction unit. Changing means for changing the size of the input buffer based on the size of the print data predicted by

[0011]

The predicting means predicts the size of print data according to the type of received data, for example. The size of the input buffer for temporarily storing the print data is changed based on the size of the print data predicted by the predicting unit. For example, when it is predicted that the data size of print data is large, the input buffer is expanded. In this way, memory resources can be effectively used to enable efficient printing processing.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

<First Embodiment> First, the structure of a laser beam printer to which the present embodiment is applied will be described with reference to FIG.

FIG. 1 is a cross-sectional view showing the internal structure of a laser beam printer (hereinafter abbreviated as LBP) according to the present embodiment. This LBP is for registering character patterns from a data source (not shown) and a partner form (form data 9). Can be registered.

In the figure, 100 is the LBP body,
Input and store print information (character code, etc.) or form information or macro commands supplied from an externally connected host computer, and create the corresponding character pattern or form pattern according to the information. An image is formed on a recording paper which is a recording medium. Three
Reference numeral 00 is an operation panel on which switches for operation and LED displays are arranged, and 101 is a printer control unit for controlling the entire LBP 100 and analyzing character information supplied from the host computer. The printer control unit 101 mainly converts character information into a video signal of a corresponding character pattern and outputs it to the laser driver 102.

The laser driver 102 is the semiconductor laser 10.
3 is a circuit for driving the laser beam 3, and the laser beam 1 emitted from the semiconductor laser 103 according to the input video signal.
Switch 04 on / off. The laser beam 104 is oscillated in the left-right direction by the rotary polygon mirror 105, and the electrostatic drum 106
Scan and expose the top. As a result, an electrostatic latent image having a character pattern is formed on the electrostatic drum 106. The latent image is developed by the developing unit 107 arranged around the electrostatic drum 106 and then transferred to the recording paper. A cut sheet is used for this recording paper. Cut sheet recording paper is a paper cassette 1 mounted on the LBP100.
08, the paper feed roller 109 and the transport roller 11
It is taken into the apparatus by 0 and 111 and supplied to the electrostatic drum 106.

Next, the control configuration of the LBP 100 will be described. FIG. 2 is a block diagram showing a schematic control configuration of the LBP 100 of the first embodiment. In the figure, reference numeral 1 is a host computer, which sends print data and the like to the LBP 100. Then, the LBP 100 analyzes the print data transmitted from the host computer 1, develops it into bitmap data, and executes printing on recording paper. Below, L
The configuration of the printer control unit 101 of the BP 100 will be further described.

Reference numeral 21 denotes a CPU, which executes overall control of the LBP 100. 22 is a ROM, and the CPU 21
Stores various control programs executed by. RO
M22 also stores a control program for executing the processes shown in the flowcharts of FIGS. 3 and 4 described later. A RAM 23 provides a temporary data storage area when the CPU 21 executes various processes. RAM2
In FIG. 3, reference numeral 231 is an input buffer that stores print data received from the host computer 1. The input buffer 231 is dynamically allocated from the free RAM area in the RAM 23 and can be released as a free RAM area. Then, the CPU 21
By allocating the input buffer from the free RAM area and releasing the input buffer to the free RAM area, the input buffer 231 is switched to two kinds of buffer sizes of small size and large size. 23
A document data counter 2 counts the number of bytes of continuously input document data. A printing unit 24 forms a visible image on a recording sheet by a laser beam method.

Next, L of the first embodiment having the above configuration
The operation of the BP 100 during printing will be described. 3 and 4 are flowcharts showing the printing process of the LBP 100 according to the first embodiment.

First, in step S11, it is determined whether print data is received. If the print data has not been received, this determination is repeated until the print data is received. When the print data is received, the process proceeds to step S12, and it is determined whether the received print data is image data. Generally, since print data including image data has a large capacity, when the image data is received, it is determined that the print data is likely to have a large capacity.

If the result of determination in step S12 is that the received print data is image data, the flow advances to step S13 to clear the document data counter 232. The document data counter 232 is a counter for checking how much document data is continuously received, and therefore the count value is cleared by receiving the image data. Next, in step S14, it is determined whether or not the input buffer 231 has already been expanded by checking whether or not the input buffer 231 has a large size. Then, in step S14, when the input buffer size is the small size (that is, when the size is not enlarged), the process proceeds to step S15, and whether there is a free RAM free area for switching the input buffer to the large size. To judge. If there is a free area, step S
In step 16, the free area is allocated to the input buffer 232, and the input buffer 231 is expanded, that is, switched to a large size. Then, in step S17, print drawing processing of the print data is performed.

On the other hand, in step S14, the input buffer 23
If 1 is already a large size, the buffer expansion process in step S16 is not performed, and the printing and drawing processes such as the expansion process to the bitmap data are performed in step S17. If there is no free area in the free RAM in step S15, the process proceeds to step S22, the free area securing process is activated, and the process proceeds to step S17. This free space securing process is, for example, a process of sequentially freeing a region, which is secured as a bitmap memory on the free RAM, as a free space.

If the received print data is not the image data in step S12, the process proceeds to step S18 in FIG. 4 and the document data counter 232 is incremented. Next, in step S19, it is determined whether the document data counter 232 is greater than 10,000. Here, if the received data is image data, the document data counter 23 in step S13.
Since 2 is cleared, the value of the document data counter 232 reaches 10000 only when the document data continues for 10000 bytes. Then, the CPU 11 sets 100
When the document data of 00 bytes or more continues, it is determined that the image data is not received for the time being. That is, it is determined that the possibility that the size of the received print data is large is not so great, and the process proceeds to step S20.

In step S20, the input buffer 231
Is a small size. Here, when the input buffer 231 is not of a small size (that is, when it is enlarged), the process proceeds to step S21, and the input buffer 231
Is released as a free RAM area, and the size of the input buffer 231 is switched to a small size. Then, the process proceeds to step S17 to print and draw the print data. It goes without saying that the free area of the free RAM area released here can be secured again as an area such as a bitmap memory. On the other hand, if the document data counter is 10000 or less in step S19, the input buffer size switching process is not performed, and the process proceeds to step S17 to execute the printing and drawing processes.

As described above, L of the first embodiment
According to the BP 100, the data amount of print data received from the host computer is predicted by the type of data (whether it is document data or image data). Then, based on this prediction, the size of the input buffer 231 is switched to the large size or the small size. In this way, it is possible to switch the size of the input buffer according to the amount of print data, improving the memory usage efficiency,
It is possible to finish printing the print data quickly. Also, when the input buffer is a small size, free RA
Since the M area can be made large, it is possible to allocate it to a bitmap memory or the like to improve the processing speed for printing.

In the first embodiment, the document data counter 232 for determining whether or not to reduce the input buffer.
The threshold value for the count value may be changed by a command input from the host computer 1 or an operation input from the operation panel 300.

In the first embodiment, the size of the data size of the print data is determined depending on whether or not it is image data, but the present invention is not limited to this. Any other algorithm that analyzes the content of data under various conditions and predicts the size of the data size may be applied. Further, not only the data size may be predicted only by the contents of the print data being received, but information about past print data may be held and the prediction may be executed with reference to the information. When referring to past information,
For example, by operating the learning function, it is possible to update the threshold value of the value of the document data counter 232 that determines the reduction execution of the input buffer.

<Second Embodiment> Next, a second embodiment will be described.

In the printer (LBP) of the first embodiment described above, the input buffer is switched according to the predicted size of the print data. However, no matter how large the input buffer is, if the size of the print data is larger, the printer will be in a busy state. At this time, the host computer waits for the printer to finish capturing the data. It is meaningful for the host computer that the time required to finally fetch all print data is short. However, while the printer repeats the busy state and the ready state, and the host computer repeatedly transmits or suspends data accordingly, the speed of data transmission is determined by the execution speed of printing. Therefore, no matter how large the input buffer of the printer is, there is no merit to the host computer. The large input buffer means that the available memory capacity for other purposes is small among the limited memory resources. As described above, the fact that the input buffer is large even though the data cannot be completely captured has some demerits, but there is no merit.

The printer according to the second embodiment improves the utilization efficiency of the memory and the print processing speed, and solves the above problems.

Also in the second embodiment, an example in which the laser beam printer is applied in the same manner as the first embodiment will be described. Therefore, this printer also has the internal structure shown in FIG. 1, and a description thereof will be omitted here.

FIG. 5 is a block diagram showing a schematic control configuration of the LBP 100 'of the second embodiment. 5, components having the same functions as those of the components shown in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted here.
The ROM 22 of the printer control unit 101 'stores a control program for the CPU 21 to execute the processes shown in the flowcharts of FIGS. In the RAM 23, the page number counter 233 stores a value obtained by counting the page number of the job being executed. The data amount counter 234 stores a value obtained by counting the data amount of the job being executed. Reference numeral 24 is a non-volatile RAM (NVRAM). N
The value stored in the VRAM 24 is retained even when the power is turned off. In the NVRAM 24, 241 is a page number recording table for each job, and the page number of the past 100 print processes is recorded for each job. A data amount recording table 242 for each job records the data amount of the past 100 jobs for each job.

Here, a job is a unit of one printing process. In the second embodiment, the host computer 1
All the print data transmitted by are enclosed by a job start command and a job end command, and one print data always starts with the job start command and ends with the job end command. The number of pages during this period is the number of pages once, and the amount of data during this period is the amount of data once.

Also in the second embodiment, the input buffer 231 is dynamically secured from the free RAM area as in the first embodiment. Then, this input buffer 231
It is assumed that the size is switched to two types, 1 KB and 50 KB. Then, this switching is executed at the timing when it is predicted that all the remaining print data will be stored in the 50 KB input buffer (according to the flowcharts of FIGS. 6 and 7 described later). A printer that specifies the size of the input buffer 231 by a command is publicly known, and a technique for dynamically securing the input buffer from the free RAM area is also publicly known, and therefore its explanation is omitted here.

The LBP 10 of the second embodiment having the above configuration
The operation of 0'will be described below. FIG. 6 is a flowchart showing the printing process of the LBP 100 ′ according to the second embodiment. First, in step S31, a memory area of 1 kilobyte (KB) is secured in the RAM 23 as an input buffer. This size of 1 KB is a relatively small value for an input buffer of a page printer. By setting the page buffer to such a small value, it is possible to secure a free RAM area that can be used for other purposes, and it is possible to increase the speed of print processing inside the LBP 100 ′. For example, a free RAM area is used as a bitmap memory used for drawing, and the number of bitmap memories is increased to improve the speed of print processing.

Next, in step S32, the timing for enlarging the input buffer is calculated. In the second embodiment, this calculation is performed according to the flowchart of FIG. First, in step S51, the number of pages per job is calculated from the number of pages of the past 100 jobs recorded in the job-specific page number recording table 241.
This is referred to as the "average number of pages". Next, step S52.
In step 1, the data amount per job is calculated from the data amount of the past 100 times of jobs recorded in the job-specific data amount recording table, and this is set as the “average data amount”. Then, in step S53, this "average amount of data"
By dividing by the "average number of pages", the "average amount of data per page" is obtained.

Next, in step S54, 50 KB is divided by "average data amount per page (KB)" to obtain "the number of pages per 50 KB" contained in the data of 50 KB. Then, step S55
Then, by subtracting "the number of pages per 50 KB" from the "estimated number of pages", the "number of expanded pages of the input buffer" is obtained. This "input buffer expansion page number" has the following meaning.

When the data amount of each page of the job being executed is equal to the "average data amount per page" and the number of pages of the job is the "average page number", the pages from the start of the job are When the input buffer expansion page number is reached, the input buffer 231 is expanded to 50 KB, so that all the data can be captured. That is, all unprocessed print data is 50K
The size of the input buffer 231 is changed from 1 KB to 50 K at the timing expected to be stored in the B input buffer.
Can be expanded to B.

Now, returning to FIG. 6, in step S33, it is determined whether or not there is received data, and if not, the reception of data is awaited. If there is received data, step S34
Then, the process proceeds to step S <b> 3 and fetches data from the input buffer 231. Next, in step S35, the data amount counter 234
To update. Next, in step S36, it is determined whether the data is a job start command. If the received data is the job start command, the process proceeds to step S37, and the page number counter 233 and the data amount counter 2
Clear 34. After clearing each counter, the process proceeds to step S38 to execute the printing and drawing processes such as analysis of received data and development into bitmap data,
Return to 33.

If the received data is not the job start command in step S36, the process proceeds to step S39 and it is determined whether or not it is the job end command. If the command is a job end command, the process advances to step S40 to read the number of pages processed by the job and the data amount from the page number counter 233 and the data amount counter 234, respectively, and the job-specific page number recording table 241 and the job This is recorded in the data amount recording table 242. Then, the process returns to step S32.

On the other hand, if the command is not a job end command, the flow advances to step S41 to determine whether the command is a paper discharge command.
If it is not a paper discharge command, the process proceeds to step S38, the printing and drawing processes are executed, and then the process returns to step S33. If the command is a paper discharge command, one page is output, so the flow advances to step S42 to increment the page number counter 232. In this way, the page number counter 23
In 2, the number of discharged pages of the job currently being executed is stored.

Next, in step S43, it is determined whether or not the value of the page number counter 232 exceeds the "input buffer expanded page number". If not, step S
After the process of 38, the process returns to step S33. If it exceeds the limit, the process proceeds to step S44, and the input buffer 23
It is determined whether or not there is a 49 KB free area required for expanding 1 to 50 KB on the RAM 23. If there is no free area, the process proceeds to step S46, the free area securing process is activated, and the process proceeds to step S38. This free space securing process is, for example, a process of sequentially freeing a region, which is secured as a bitmap memory on the free RAM, as a free space.

On the other hand, if there is a free area in step S44, the flow advances to step S45 to allocate the memory from the free RAM area and use it as an input buffer to enlarge the input buffer 231. Then, through the processing of step S38, step S3
Return to 3.

As described above, the LB of the second embodiment
According to P100 ′, the average page number and data amount of the job are obtained from the page number and data amount for each past job, and the timing for changing the size of the input buffer is calculated. Then, by increasing the size of the input buffer at this timing, it is possible to improve the memory use efficiency and release the host computer from the data transmission work in a short time.

In the second embodiment, the input buffer is 1
It is supposed to be expanded from KB to 50 KB, but the present invention is not limited to this. The size of the input buffer before and after expansion may be changed by a command from the host computer or a setting operation from the operation panel, or an appropriate buffer size can be set by the learning function with reference to the past data amount. May be configured to be set.

Further, in the present embodiment, the estimated number of pages and the estimated data amount are simply the average values of the past 100 printings, but the present invention is not limited to these. It goes without saying that various algorithms for calculating the predicted number of pages and the predicted value of the predicted data amount can be applied.

Furthermore, it is also possible to combine the processing for switching the size of the input buffer according to the above-described first and second embodiments. Further, although the size of the input buffer is switched between large and small, it is possible to implement a plurality of switching of three or more types more easily than the configuration of the present invention.

A laser beam printer has been described as an example of the image forming apparatus of this embodiment, but the image forming apparatus is not limited to this and is applicable to an ink jet printer described below.

<Schematic Description of Apparatus Main Body> FIG. 8 is a schematic view of an ink jet recording apparatus IJRA to which the present invention can be applied. In the figure, the carriage HC that engages with the spiral groove 5004 of the lead screw 5005 that rotates via the driving force transmission gears 5011 and 5009 in conjunction with the forward / reverse rotation of the drive motor 5013 has pins (not shown). Then
It is reciprocated in the directions of arrows a and b. This carriage HC
Inkjet cartridge IJC is mounted on. A paper pressing plate 5002 presses the paper against the platen 5000 in the moving direction of the carriage. 5
Reference numerals 007 and 5008 denote photocouplers for confirming the presence of the carriage lever 5006 in this area, and checking the motor 501.
3 is a home position detecting means for switching the rotation direction of the motor 3. Reference numeral 5016 denotes a member that supports a cap member 5022 that caps the front surface of the recording head.
Reference numeral 5 denotes a suction means for sucking the inside of the cap, which performs suction recovery of the recording head via the opening 5023 in the cap. 5
Reference numeral 017 is a cleaning blade, and 5019 is a member that allows this blade to move in the front-rear direction, and these are supported by a main body support plate 5018. Needless to say, a well-known cleaning blade can be applied to this example instead of this form. Reference numeral 5012 denotes a lever for starting suction for suction recovery, which moves in accordance with the movement of the cam 5020 that engages with the carriage, and the movement of the driving force from the driving motor is controlled by a known transmission means such as clutch switching. To be done.

The capping, cleaning, and suction recovery are configured so that the desired processing can be performed at their corresponding positions by the action of the lead screw 5005 when the carriage comes to the area on the home position side. As long as the desired operation is performed at the timing, any of the above can be applied to this example.

<Description of Control Configuration> Next, a control configuration for executing the recording control of the above-mentioned apparatus will be described with reference to the block diagram shown in FIG. In the figure showing a control circuit, 1700 is an interface for inputting a recording signal, 1701 is an MPU, 1702 is a program ROM for storing a control program executed by the MPU 1701,
1703 is a dynamic type R for storing various data (recording data, recording data supplied to the head, etc.).
OM. A gate array 1704 controls the supply of print data to the print head 1708, and includes an interface 1700, an MPU 1701, and a RAM 1703.
It also controls data transfer between them. 1710 is the recording head 17
08 is a carrier motor for carrying, and 1709 is a carrying motor for carrying the recording paper. Reference numeral 1705 is a head driver for driving the head, and 1706 and 1707 are motor drivers for driving the carry motor 1709 and the carrier motor 1710, respectively.

The operation of the above control structure will be described. When a recording signal is input to the interface 1700, the gate array 1
A recording signal is converted between the 704 and the MPU 1701 to print data for printing. And the motor driver 1
The recording heads 706 and 1707 are driven, and the recording head is driven according to the recording data sent to the head driver 1705 to perform printing.

It is obvious that the constituent elements of the present invention can be incorporated in the control structure of the ink jet printer as described above, and the present invention is not limited to the laser beam printer and can be applied to the above ink jet printer and the like.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device. Further, it goes without saying that the present invention can also be applied to a case where it is achieved by supplying a program that causes a system or an apparatus to execute the processing defined by the present invention.

[0055]

As described above, according to the printing apparatus of the present invention, the size of the received data can be predicted and the size of the input buffer can be changed based on the prediction result. There is an effect that the utilization efficiency and the efficiency of print processing are improved.

[0056]

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the internal structure of a laser beam printer of this embodiment.

FIG. 2 is a block diagram showing a schematic control configuration of an LBP according to the first embodiment.

FIG. 3 is a flowchart illustrating LBP printing processing according to the first embodiment.

FIG. 4 is a flowchart illustrating an LBP printing process according to the first embodiment.

FIG. 5 is a block diagram showing a schematic control configuration of an LBP according to a second embodiment.

FIG. 6 is a flowchart illustrating an LBP printing process according to the second embodiment.

FIG. 7 is a flowchart illustrating a procedure for calculating the timing of input buffer expansion processing according to the second embodiment.

FIG. 8 is a diagram showing an overview of an inkjet recording apparatus.

FIG. 9 is a block diagram showing a control configuration of the inkjet recording apparatus.

[Explanation of symbols]

 1 Host Computer 21 CPU 22 ROM 23 RAM 24 Printing Unit 100 Laser Beam Printer 101 Printer Control Unit 231 Input Buffer 232 Document Data Counter

Claims (5)

[Claims] 1. A printing device for printing based on print data received from an external device, a storage device for temporarily storing received data in an input buffer, and a prediction device for predicting the size of the print data. A printing device comprising: a changing unit that changes the size of the input buffer based on the size of the print data predicted by the predicting unit. 2. The predicting unit predicts that the print data is large when the print data includes image data, and the change unit inputs the input when the predicting unit predicts that the print data is large. The printing apparatus according to claim 1, wherein the size of the buffer is increased. 3. The predicting unit predicts that the print data is small when receiving a predetermined amount of continuous document data that does not include image data in receiving the print data, and the changing unit determines the predicting unit. When the print data is predicted to be small by, the size of the input buffer is reduced, and the printing apparatus according to claim 1 or 2. 4. A printing device for printing based on print data received from an external device, storage means for temporarily storing received data in an input buffer, expansion means for expanding the size of the input buffer, and Prediction means for predicting the size of print data, and based on the size of the print data predicted by the prediction means, all of the unprocessed print data is accumulated in the input buffer expanded by the expansion means. A printing apparatus comprising: a timing generation unit that generates a possible timing, and the expansion unit is executed at the timing generated by the timing generation unit. 5. The predicting means predicts the total number of pages and the data amount per page of the print data received based on a plurality of past print data, and the timing generating means determines the prediction result of the predicting means. The number of pages of print data that can be stored in the expanded input buffer is calculated based on the number of pages, and when the number of pages of the print data is subtracted from the total number of pages predicted by the predicting unit, the number of pages is obtained. The printing apparatus according to claim 4, wherein a timing for executing the expansion unit is generated.