JPH0229353A - Printer - Google Patents

Abstract

PURPOSE:To obtain an inexpensive high-performance printer through the most effective use of a memory by providing a means for variably setting a memory capacity to be used for storing bit mapping data. CONSTITUTION:A CPU in a printer controller 3 decides whether a memory region for storing a one-page amount of bit mapping data is to be secured in a RAM 12, according to the total usable capacity of the RAM 12, use conditions of the RAM 12, the kind of printing data, the amount of data for one page, etc. When the RAM 12 is used by a full bit mapping system in which the memory region capable of storing the one-page amount of bit mapping data is secured in the RAM 12, the one-page amount of bit mapping data is formed in the memory, and is then outputted to a printer engine 4, whereby even a complicated figure is printed normally. When the usable capacity of the RAM 12 is so low that a memory region for storing the one-page amount of bit mapping data can not be secured, a memory region for storing only bit mapping data for a part of one page is secured, and printing is conducted by a partial bit mapping system.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a laser printer and an LED printer.

The present invention relates to a page printer using a dot printing method such as an LCD printer.

(Prior art) In an electrophotographic page printer such as a laser printer, each page is created based on source data (such as character font data and image data) and page data (information sent from an external device). data)
Creates video data, which is bitmap information, in memory.

The printing process involves reading out the video data and printing it on paper.

In the case of a laser printer, a laser beam that main scans the surface of a photoreceptor to form an image is modulated in accordance with the read video data.

In such printers, if the full bitmap method is used in which one page's worth of information is converted into bitmap information and stored in memory in advance, the work of converting to bitmap information cannot keep up with the printing work and printing becomes impossible. This problem does not occur, but 1 of the maximum printable paper
Since it is necessary to always reserve a memory area to store bitmap information for pages, there is a problem in that the amount of memory that can be used for downloading fonts, form overlays, etc. is reduced.

On the other hand, if you reduce the memory area for storing bitmap information to less than one page and use the partial bitmap method, in which parts of the bitmap information are converted into bitmap information and printed, you will have more memory space for downloading fonts, form overlays, etc. However, there is a problem in that the work of converting to bitmap information cannot keep up with the printing work, and printing may not be possible.

This problem is less likely to occur if the amount of memory allocated to store bitmap information is large, and it also depends on the type of information you want to print (two characters, two figures, etc.), the amount of information for one page, etc. The user could only select one of the above two methods, and the memory could not be used most effectively.

In addition, in order to improve memory usage efficiency, intermediate information (information transmission format inside memory) is created for each drawing element (for example, one character), and the output of bitmap information (video data) to the printer engine is controlled. The software or hardware used to create video data in a video buffer inside a memory in units of multiple lines based on the intermediate information is output to a printer engine.

In this case, video data must be created and transferred to the video buffer within a certain period of time, so depending on the amount of information for one page, a lack of processing time may occur, resulting in so-called data loss (printing This poses a problem:

As an improvement measure, the above-mentioned full bitmap method can be used to avoid the worst case of data loss, but depending on the memory capacity that can be secured (if multiple pages cannot be secured), it may take up to Since the next data operation cannot be performed, there is a drawback that usage efficiency decreases.

(Problem to be Solved by the Invention) The invention as set forth in claim (1) of the present invention concerns the storage of the bitmap information in the memory (video buffer), the type of information sent from an external device, and the information for one page. This is an attempt to solve the problem that it was not possible for the user to set the memory amount for storing bitmap information to the optimum amount according to the data that the user wants to print.

In addition, the invention according to claims (2) to 4) of the present invention provides that, regarding the storage of the bitmap information in the memory (video buffer), the type of information sent from an external device;
The purpose of this invention is to eliminate the drawbacks of the full bitmap method and the partial bitmap method with respect to page information, etc., and to take advantage of their advantages to prevent deterioration in memory usage efficiency.

(Objective of the Invention) An object of the invention described in claims (1) to 4) is to use the memory for storing bitmap information most effectively.

Another object of the invention described in claim (1) of the present invention is that the user can variably set the memory capacity depending on the type of information sent from an external device, the amount of information for one page, etc.

Further, the invention according to claims (2) to 4) receives all information sent from an external device, compresses data of one page or more as necessary, and prevents data loss. Along with storing it in memory.

The purpose is to use memory efficiently.

(Structure and operation) In order to achieve the above object, the invention described in claim (1) of the present invention converts information sent from an external device into bitmap information and stores it in a memory, and prints using the bitmap information. The present invention is characterized in that the printer used for the work is provided with means for variably setting the amount of memory used to store the bitmap information.

This allows you to select whether the amount of memory for storing bitmap information is automatically changed for one page or for partial pages, depending on the memory capacity that can be used by the printer controller. Set by key switch,
Make the most efficient use of memory.

Further, in order to achieve the above object, the invention according to claims (2) to 4) converts information sent from an external device into bitmap information and stores it in a memory. In a printer that performs printing operations based on bitmap information, there are a means for directly converting the information into bitmap information, a means for creating intermediate information for the conversion into bitmap information, and a memory usage amount for this intermediate information as described above. If the size is larger than that required for conversion into bitmap information, the invention is characterized by providing means for automatically converting it into the bitmap information in preparation for printing work.

Since this uses run-length encoding fonts or scanline conversion as intermediate information, data is compressed and can be performed with a small memory capacity up to the printing operation.

(Embodiment) FIG. 1 is a functional block diagram showing the basic configuration of the invention as claimed in claim (1), in which information conversion means A converts print information sent from an external device into bitmap information;
A memory B that stores the bitmap information converted by this, a printer engine C that performs printing work based on the bitmap information, and a variable amount of memory that variably sets the amount of memory used to store the bitmap information among the memory B. It is equipped with a setting means.

Therefore, by varying the amount of memory used to store bitmap information using a memory amount variable setting means, depending on the type of printing information, the amount of information for one page, or the purpose of printing, the full bitmap method and the partial bit Not only can you arbitrarily select the map method, but even if you use the partial bitmap method, you can set the amount of memory reserved for storing bitmap information to the optimal amount, and use the memory effectively according to the usage situation. .

FIG. 2 is a system configuration diagram of an embodiment in which the present invention is applied to a laser printer, in which 1 indicates external devices such as a personal computer, a word processor, and a data processing device 2.
A host such as an image processing device 2 is a laser printer which is a page printer.

Laser printer 2 receives the character code from host 1.

A printer controller 3 that inputs print information such as images (graphics) and creates bitmap information (video data) on a page-by-page basis, an image creation unit that prints characters and images on paper using the bitmap information, and its sequence controller. The printer engine 4 is composed of a printer engine 4, etc.

FIG. 3 is a block diagram showing the internal configuration of the printer controller 3. As shown in FIG.

This printer controller 3 has an interface (I/
F) includes a host interface 5 for connecting to the host 1, an engine interface 6 for connecting to the printer engine 4, and an operation unit (control panel) 8 for connecting to the printer engine 4. Panel interface 7 and proppi disk device 13
．． Readable/writable RAM cartridge 14. It is provided with an opsimin interface 9 for connecting to an opsimin interface such as a read-only ROM cartridge 15 or the like.

CPU10 is a microcomputer that controls the entire printer controller, and also functions as memory amount variable setting means together with information conversion means A in FIG. 1 and operation section 8 to be described later.

ROMII is a program memory, and stores resident fonts and the like in addition to programs for controlling the CPU10.

RAM12 is a large capacity random access memory,
It is mainly used for the following purposes.

(,) input buffer (b) page buffer (C
) Video buffer (d) System memory (e) Font file (f) Image file Among these, the video buffer is an area corresponding to memory B used for storing bitmap information in Figure 1, and these buffers and The file is.

A RAM area other than that used for system software is reserved and used in advance with the required capacity. In this case, if the memory capacity is insufficient, a message to that effect is displayed and the function is abandoned.

In that case, it is necessary to erase some data and restore it to a usable state. That is, instead of allocating and using the entire memory area in a fixed manner, a dynamic management method is adopted in which an area is secured and used each time it is needed.

Section 22 describes the functions of each buffer and file.

[Input buffer]

A host machine connected to the host interface 5 sends data irregularly, regardless of the operation within the printer controller 3.

Therefore, data from the host interface 5 is temporarily held in the input buffer.

The printer software sequentially retrieves and processes the data.

[Page buffer]

The source address where the data is actually stored in the data sent from the host machine.

Page data is created in this page buffer by adding information such as a destination address and size that specify where in the video buffer the video data is to be created.

(Video Buffer) Video data, which is bitmap information, is created in the video buffer by using page data of a page buffer, font data of a font file (described later), and possibly image data of an image file.

This video buffer has full bitmap mode and partial bitmap mode, and can be used in either mode.

Full bitmap mode is a mode in which a memory area corresponding to the entire paper size is allocated and used as a video buffer, and partial bitmap mode is a mode in which a memory area corresponding to a portion of the vapor size (for example, 1/8 page) is allocated and used. In this mode, it is allocated as a video buffer and alternately uses half of it.

[Font file]

All fonts are treated as files, and serve as source data when expanding video data into a video buffer. So with a list showing the addresses where the available fonts are stored.

A list is provided in the form of a table showing the addresses of each character within each font.

Fonts include bitmap fonts and vector fonts. Bitmap fonts are represented by a rectangular dot matrix, and vector fonts have character outlines represented by a collection of functions such as straight lines or circles.

This font file can be owned internally as a ROM, externally as a font cartridge, or downloaded from the host through the host interface 5.

[Image file]

Sequentially stores image data sent from the host,
Create an image file. If the video buffer is in full bitmap mode, image data can be stored directly in the video buffer without creating this image file.

In partial bitmap mode, it is created in a memory area that can be used as an image file. and,
Each image file is given an identification code and incorporated into the page buffer.

The operation unit (control panel) 8 includes, for example, a liquid crystal display (LCD) display 1 that can display characters such as various messages.
6, a plurality of key switches 17, and other key switches and display LEDs (not shown).

Next, the operation of this embodiment will be explained.

The RAM 12 shown in FIG. 3 is placed in the memory area shown in FIG.
) When using the full bitmap method, which secures a memory area that can store one page of bitmap information, the area that can be used to store data such as font downloads and form overlays is indicated by hatching. becomes very small.

Therefore, restrictions tend to apply when downloading fonts from the host 1, ROM cartridge 15, etc.
As shown in FIG. 5, one page's worth of bitmap information is created in the memory and then output to the printer engine 4, so even complex figures can be printed without any problems.

On the other hand, when the RAM 12 is used in a partial bitmap method in which a memory area for storing partial bitmap information for less than one page is secured as shown in FIG. 4(B).

Since a large area can be used to store data such as font downloads, which are shown by hatching, many fonts can be stored.

However, as shown in FIG. 6, when bitmap information for a portion of a page is created, it is output to the printer engine 4, so large and complicated figures cannot be processed.

Therefore, whether or not to secure one page's worth of memory for storing bitmap information on the RAM 12 is determined based on the total usable capacity of the RAM 12, its usage status, and the type of print information.
Depending on the amount of data for each page, etc.

The CPU 10 of the printer controller 3 makes a determination.

When the usable capacity of the RAM 12 is small and it is impossible to secure enough memory to store one page's worth of bitmap information, it is possible to secure enough memory to store only part of the page's bitmap information and use partial bits. Printing is done using the map method.

However, RA that can store one page of bitmap information
M capacity, but for reasons such as having a large number of downloaded fonts, the amount of memory for storing bitmap information is reduced to a partial page, and printing is performed using the partial bitmap method. is also possible.

The following table summarizes the amount of memory required and its advantages and disadvantages depending on the type and amount of data you want to print.

In this way, the amount of memory for storing bitmap information is reduced to 1.
Using the key switch 17 of the operation unit 8, it is possible to set whether or not to automatically change whether to print a page or a partial page depending on the memory capacity that can be used by the printer controller 3.

In that case, for example, turning on the key switch S1 will fix the full bitmap method, turning on the key switch S2 will fix the method to the partial bitmap method, and turning on the key switch S will set the automatic change of both methods. This allows the operator to select any one of them.

Further, such selection setting can also be performed by a command from a host, which is an external device.

Next, a description will be given of changing the amount of memory for storing bitmap information in the partial bitmap method.

Even in the partial bitmap method, as described in the table above, when printing composite data of characters and simple figures, the amount of bitmap information increases, so the amount of memory to store it must be reduced. Must be increased.

In such a case, for example, the bitmap information storage area on the RAM 12 shown in FIG.
Expand only.

At that time, it may be necessary to also use part of the area indicated by (opening) where downloaded fonts and form overlay data are already stored.

In that case, the CPU10 determines the information that is not currently being used and deletes the information in the cross-hatched area shown in FIG. floppy disk! [Evacuate to 13 or RAM cartridge 14 and save.]

When the printing operation is completed and the expanded bitmap information storage area is no longer needed, the CPU 10 reads out any information saved in the external device as mentioned above and stores it again in the RAM 12. , has the ability to recover information.

When the printer controller 3 automatically expands the amount of memory used to store bitmap information, the CPU 10 calculates the time required to convert the input information to bitmap information, and calculates the conversion time. If it is determined that the bitmap information is required for a long time and cannot keep up with the printing work, abnormal printing can be avoided by providing a function to expand the amount of memory for storing bitmap information.

In this way, the amount of memory for storing bitmap information is automatically set according to the information you want to print, so you can always use the entire memory capacity effectively, and you can use a relatively small amount of memory. It is possible to provide a printer that exhibits high performance even when used.

If the required amount of memory cannot be secured, the situation is displayed on the liquid crystal display 16 of the operation unit 8 or the host 1 is notified, and the information specified from the operation unit 8 or the host 1 is deleted or The data may be saved in the device to secure the necessary amount of memory.

Furthermore, the amount of memory used for storing bitmap information may be arbitrarily set from the operation unit 8 or the host 1.

For example, when setting from the operation unit 8, after selecting the memory amount setting mode with the key switch s1 of the key switches 17 in FIG. 3, the memory amount increases step by step each time the key switch S is pressed. The memory amount can be made to decrease step by step each time the key switch S is pressed.

Even when the amount of memory for storing bitmap information is arbitrarily specified in this way, the printer controller 3
When the specified amount of memory cannot be secured, the required amount of memory is secured as follows, as in the case described above.

(a) Automatically delete or save font information etc. that are not currently in use.

(b) Display the situation in which the specified amount of memory cannot be secured on the liquid crystal display 16 of the operation unit 8 or notify the host 1, inquire about information to be erased or saved to an external device, and send the specified information. Erase or evacuate.

In this way, the amount of memory for storing bitmap information can be set to the optimum amount according to the data the user wants to print, and relatively small memory capacity can be used effectively to achieve low cost and high performance. It is possible to provide a printer that can perform the following functions.

The embodiments in which the present invention is applied to a laser printer have been described above, but the present invention is applicable to other optical printers, etc. that convert information from an external device into bitmap information and store it in a memory, and perform printing operations using the bitmap information. This can be similarly applied to other page printers.

Next, embodiments of the invention according to claims (1) to 4) will be described.

In this embodiment, the CPU 1 of the printer controller 3 shown in FIG.
The target is the ROM II and RAM 12 controlled by 0. In particular, the bitmap information (video data) stored in the video buffer of the RAM 12 will be described.

8 to 13 are diagrams for explaining the configuration and operation of the present invention, and FIG. 8 shows an example of the configuration of the RAM 12.

In the figure, 12A is the system working memory, 1
2B is font download load memory, 12G is run length encoding (RLE) record memory.
The memory 120 is an image record memory, and the memories 12G and 12D are dynamically increased and decreased.

In addition, if the CPU 10 of the control 3 has a full bitmap memory configuration as determined during processing, for example, the CPU 10 of the control 3
In a 00 DPI printer, the memory is configured with the dot size as shown in FIG. 9 in mind.

The Y scan line table of the full bitmap memory in FIG. 9 is shown in FIG.
One of the records illustrated in the figure has been described and given an address. If there is no record, a null record is assigned to the primary record address (Next RecordAddress). The primary record address here indicates the memory address where other code for chaining records in the same scan line is stored. If there is no other record to chain, a null record is assigned. , this null record is assigned a special value that does not become a memory address, such as "0" or "FFFFFFFF".

Further, χ5tart and end indicate respectively the starting point and ending point on the scan line whose drawing form is determined by the modification information, and the modification information indicates the drawing form between the starting point and the ending point.

Next, the record creation procedure of the embodiment according to the present invention will be explained with reference to FIG. 13 using the drawing example of FIG. 12.

(2) Initialize the Y scan line table (FIG. 10) (all n-th scan lines are recorded as null) and prepare for record creation (FIG. 13 (1)).

(2) When the external device (host 1) requests, for example, to print the character "A" shown in FIG. 12, the following explanation will be given using the n-th scan line in FIG. 12 as an example.

As shown in the figure, CPTJIO extracts the black portion on the nth scan line based on the font information. At this time, for data compression, the font information is easily obtained as so-called intermediate information that has been run-length encoded (information indicating the bit length of white or black corresponding to the scan line).

Based on this extracted intermediate information, a record as shown in FIG. 13(2) is created. That is, a record ■ is created (from the starting point 100 dots of the character rAJ to the ending point 1
03 dot), at this point the content of the nth scan line in the Y scan line table indicates the address of record (2).

Next, a record (2) is created. At this time, the information stored in the Y scan line table is entered into the next record address in the record, and the address of the record (2) is entered into the Y scan line table. Thereafter, records are added one after another in the same manner.

■ Next, if it is requested to draw a circle that overlaps with "A", dot 160 from 118 on the nth scan line.
Record (3) for drawing dots is created as intermediate information by means of scan line conversion (extraction of data for each scan line).

First, the contents of the Y scan line table are recorded as
The next record address (this content indicates the address of record ■) is entered, and the address of record ■ is entered into the Y scan line table.

In this case, the starting point is 118 dots, and the χ ending point is 160 dots.
It becomes a dot, and the type of pattern to be drawn (black in this example) is stored in the decoration information.

Next, we will describe the procedure for printing based on the record created as described above.

Normally, a video buffer is composed of multiple scan line buffers, and one for outputting to the printer engine 4 and one for preparing data for the next scan line are used in rotation. .

When the CPU 10 of the printer controller 3 prepares data for the next scan line, it reads the records chained based on the contents of the Y scan line table and stores one scan line worth of dot image data in the scan line buffer. create.

At this time, basically seed processing with fewer records to be chained becomes faster. On the other hand, if there are too many records, the buffer will be switched to the video output buffer during data preparation, resulting in data loss.

Here, if the system operates in full bitmap mode from the beginning of startup, video output will start after one page of image is complete, so a constant transfer from bitmap memory to video buffer will be required. If you can clear the time, there is no need to worry about data loss.

Furthermore, if the transfer time is met, video data (bitmap information) can be output directly to the printer engine 4 without going through the video buffer.

■ If the qualification information of the record ■ is "black," the data on the same scan line can simply be chained as described in ■ above, but as mentioned above, due to the transfer time, the data In order to eliminate loss etc., it is better to have fewer records.

Therefore, since the drawing based on record ■ in Figure 13 (3) is included in record ■, record ■ is no longer necessary. Put the contents of the next record address of ■ into the next record address of record ■, and remove record ■.

At this time, in order to maintain the continuity of usable memory, measures to prevent data loss (garbage collection, etc.) are performed.

(2) Next, the number of record chains increases, and even if the above operation (2) is performed, the record memory capacity for one scan line may exceed the dot image memory capacity for one scan line.

In such a case, dot image data for one scan line is created based on the data in the record as shown in Figure 13 (5).
Create the scan line as shown in Figure 2, and prevent the record memory capacity for that scan line from increasing any further. After that, dot image data is additionally created in the image record for everything to be drawn on the n-th scan line.

As described above, all information sent from external devices is stored in memory, data compression and other measures are taken to prevent memory capacity from increasing, and the advantages of full bitmap and partial bitmap methods are utilized. I try to use intermediate information to make the most of this.

(Effects of the Invention) As explained above, the invention according to claim (1) of the present invention provides data for printing the amount of memory used for storing bitmap information in a printer that performs printing work based on bitmap information stored in memory. Since the memory can be set to the optimum amount according to the storage capacity and memory capacity, it is possible to use the memory most effectively and provide a printer that is inexpensive and exhibits high performance.

Furthermore, since the invention described in claims (2) to 4) uses run-length encoding as intermediate information, the storage of bitmap information up to the printing operation can be configured with a small memory capacity. .

In drawing graphics (geometric figures),
Data extraction for each scan line (scan line
Since the intermediate result of the conversion (conversion) is used as run length encoding information, the storage of bitmap information up to the printing operation can be configured with a small memory capacity.

Also, rather than creating intermediate information in the record.

If a full bitmap is possible, processing within a page may be speeded up.0 If processing performance within a single page is required, even if bitmap information is being created by a record chain, the present invention may be able to speed up processing within a page. It is easy to develop into a bitmap.

Additionally, if there is not enough memory available for record creation, the downloaded images and fonts are changed to run-length encoding and data is compressed. This compressed data can be easily used as record creation information as is. If the memory shortage is resolved, you can use the image or font as is without having to restore the original image or font.

In addition, since only a certain amount of memory is required to represent data for one scan line, it is also possible to represent data by combining multiple scan lines.

By changing the configuration of the video buffer, at least 1
Full bitmap memory for a page can be secured, so
Printing can be performed without data loss.

[Brief Description of the Drawings] Fig. 1 is a functional block diagram showing the basic configuration according to claim (1) of the present invention, and Fig. 2 is an implementation in which the functions of Fig. 1 are applied to a laser printer. FIG. 3 is a block diagram showing the configuration of the printer controller in FIG. 2, and FIGS. 4 to 7 are explanatory diagrams for explaining the functions of this embodiment. 8 to 13 are claims (1) to (4) of the present invention.
FIG. 8 is an explanatory diagram for explaining the functions of the embodiment of R.
A side view of the configuration of AM12, FIG. 9 is an example of a full bit map, FIG. 10 is an example of a Y scan line table, FIG. 11 is an example of the record in FIG. 10, and FIG. 12 is a drawing handled by this embodiment. The side view, FIG. 13, is an explanatory diagram of the record creation procedure for FIG. 12. A... Information conversion means, B... Memory for storing bitmap information, C... Printer engine, D.
...Memory amount variable setting means, 1...Host, 2
... Laser printer, 3 ... Printer controller, 4 ... Printer engine, 5 ... Host interface, 6 ... Engine interface, 8 ... Operation unit (control panel), 10.
...CPU (microcomputer), 11...
ROM (program memory), 12...RAM (large capacity random access memory). Figure 2

Claims (4)

[Claims] (1) Used to store the bitmap information in a printer that converts information sent from an external device into bitmap information and stores it in a memory, and performs printing using the bitmap information stored in the memory. A printer characterized in that it is provided with means for variably setting the amount of memory to be stored. (2) In a printer that converts information sent from an external device into bitmap information and stores it in memory, and performs printing operations using the bitmap information stored in the memory, converts the information directly into bitmap information. means for creating intermediate information for conversion into the bitmap information; and if memory usage by this intermediate information is greater than the amount of memory used by the conversion into the bitmap information, automatically converting into the bitmap information; A printer characterized in that it is provided with means for preparing for printing work. (3) The printer according to claim (2), wherein the intermediate information is run-length encoding font or scanline converted information. (4) Full bitmap memory for one page is secured, and when it is determined that continuous printing with the current page is impossible in information processing for the next page, the full bitmap memory is used. The printer according to claim (2).