JPS5936778B2 - data printing device - Google Patents

Description

BACKGROUND OF THE INVENTION The present invention relates to raster-based printers that print text and image data in response to coded digital input data, and more particularly to raster printers that print text and image data in response to encoded digital input data. The present invention relates to a raster-type printer that can print characters with different values at any position on a printed page, regardless of the order in which they are received by the printer.

Printers that print graphic characters in response to character data encoded in binary format are used in many data processing operations and devices.

Such printers respond to incoming coded character data to physically print the graphic characters represented by the code of the character data. Printing can occur in a number of ways, including by means of well-known impact printers. In impact printers, graphic characters are generated by selecting a single type. That is, the type strikes paper or other printable media to generate the desired graphic characters. Non-impact printers are also used in the prior art. In non-impact printers, graphic character data is generated on a printable medium by depositing some marking medium onto the paper without physically impacting a single type or other similar element. be done. The prior art printers described above have a number of disadvantages that often limit their usefulness.

One of its disadvantages is the limited number of prints that can be produced and the lack of flexibility in placing characters on the printed page. For example, it was not possible with prior art printers to print a series of characters going in any direction (i.e., up, down, left, or right), and no printer was known that could change the size of the characters at any time. Ta. BRIEF DESCRIPTION OF THE INVENTION The present invention provides a highly flexible raster scan printer that can print characters of any size anywhere on the page.

Raster scanning printers (typically laser beam printers or ink generator printers) scan a page with recorded dots in a raster pattern to print characters or graphics of arbitrary shapes using combinations of dots. . A bit pattern, which is an electronic image of the character or graphic dot pattern to be recorded, is placed in a print buffer from which bits are sequentially removed to produce recorded dots at corresponding points on the raster scan. The present invention achieves the above objects by using a novel technique for forming dot patterns in the printing buffer.

The incoming text data presented to the printer does not necessarily match the printer's raster scan progression order. Since the raster scan pattern of a raster scan printer is fixed and the dots to be recorded must be presented to the printer synchronously as the scan progresses, the dot pattern representing the input text data provided is It is necessary to take special measures to extract the data in order, or to rearrange them in the scanning order. This problem becomes complicated when trying to place arbitrary sized text anywhere on the page. Raster of all pages
A pattern can be thought of as a matrix arrangement of subarrays that are partial sections.

For example, in an example where one raster scanning line is divided into 4096 dots and one page has 5000 scanning lines, one subarray can be defined as 32 dots x 32 scanning lines. In a typical example, one subarray includes a pattern of dots representing one standard size character. It is not necessary that one subarray contain a dot pattern for one character, and a subarray can be defined as a partial section of a page of any size.

Therefore, one character may be composed of multiple subarrays. A subarray is the unit used in the present invention to assemble the final page image into a buffer.
In the present invention, the incoming text data is rearranged in code form and stored in a table before placing the final image in the buffer. In this table, code-type data characters representing character images that should appear on the same scanning line of the raster are linked by addresses attached to each character so that they are linked one after another in the order in which they appear on that scanning line. ing. The first character appearing on a scanline is called by a list head located in another scantable. The last character on a scanline links to the list head of the next scanline in the scan table. Therefore, if the head of the list of the first scanning line of the scanning table is called first, the characters that should appear in the order of raster scanning progress will be called out one after another. specifying the location on the page for the incoming text data;
As mentioned above, the task of arranging the data in the table is the task of the processor, and its detailed explanation will be omitted.

In addition, in the table arrangement described above, each character is linked to each other in the table by an address, so adding a character to any position is easy by simply changing the link address of the characters before and after it. be able to. Furthermore, it is clear that the above-mentioned method of configuring a table can easily be configured with either a vertically typed page, a horizontally typed page, or a combination thereof. In addition to the link address, each data character in the table is accompanied by control information such as the size of the character, its position within the subarray, and the location of the corresponding dot pattern.

Each time a character is read out from the table according to the location indicated by the scanning table, these control information are taken into the control register, and under the control of this register, the corresponding dot pattern is retrieved from the storage location specified by the control information. and written to the buffer in subarray units. The dot pattern images thus assembled in the buffer are arranged according to the inherent scanning order of the raster printer and may be provided to the printer for final printing or stored for later use. good.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a data processing system 10 including a printer of the present invention connected to a main channel 14 of a data processing unit (computer) 16.

Printer 12 forms an input/output device, and main channel 14 may be connected to other human output devices, indicated at 18 in FIG. The general operation of data processing system 10 in combination with printer 12 is described in the IB
M System/370 operating principle (IBMSys-Tem/
370Princip1es0f0perati0ns
, f0rmGA22-700).

As described in this publication, a data processing unit 16, which typically includes a central processing unit and a main store, communicates with printers and other input/output devices 18 via a main channel 14. The character code byte is generated in the data processing unit 16 and sent to the main
Under the control of a channel command word sent to channel 14, it is communicated to printer 12. Each character code byte represents a different character or image to be printed by printer 12. Character data also includes certain types of control data. Other channel command words generated in data processing unit 16 include operating constants used in printer 12 and printer 12
and instructions for the operation of. FIG. 2 shows the basic configuration of the printer 12 of FIG. 1 according to the present invention.

Printer 12 is connected to system adapter 2 via a channel attachment to main channel 14.
Contains 0. Data from data processing unit 16 is communicated on the main channel to the channel attachment, from there via external registers 22 to microprocessor 24, and thence to control store 26.
The printer can process data records of up to 2000 bytes transferred from the channel. Furthermore, the external register 22 includes a raster pattern memory 38,
Data is provided to a raster image generator 28 and to an imaging device 32 via a Process Control and Operator Panel adapter 34. Imaging device 32 includes a device responsive to the modulated laser to thereby deposit toner on the discharged print drum area and transfer it onto the paper. However, imaging device 32 may be any suitable raster-type printing device that prints desired character graphics in response to character data. The microprocessor 24 stores data from the data processing unit 16 and stores it in a store controlled by the printer user.
It executes various microroutine instructions of the microprogram loaded from the disk storage device 26.

Each component of the printer is controlled by a microprocessor using external registers as an interface. This control is also performed for the system adapter 20. However, it will be apparent to those skilled in the art that the printer may be controlled by hard-wired logic circuitry.
“Process Control and Operator Panel” Adapter 34
is an interface to the imaging device 32;
Microprocessor 24 controls printing through this interface. The adapter 34 provides paper control signals and start signals for the printing process, and the imaging device 3
An alarm signal is provided to the microprocessor 24 based on the status signal from the microprocessor 2. Additionally, adapter 34 forwards all operational indication signals occurring at the operator panel to microprocessor 24. Signals are also returned from the microprocessor 24 to the process control adapter 34 to control the appropriate indicator lights on the operator panel. Raster image generator 28 produces printed pages.

Microprocessor 24 interprets control signals transferred from the host system and prepares printed pages. Microprocessor 24 then plays an active role in the page printing process. The character pattern used for printing is
Retained in raster pattern memory 38. Raster pattern memory 38 must be loaded with character patterns by microprocessor 24 before printing can occur. Auxiliary storage device (disk)
36 is used to store initial microprogram load operations, diagnostic programs and error logs.
Microprocessor 24 controls all seeks and data flow in auxiliary storage 36. FIG. 4 shows the raster image generator components and their associated circuitry.

The manner in which a raster image generator produces a page to be printed may be understood by reference to FIG. The microprocessor is a pattern movement control circuit 4
Each component of the raster image generator is controlled through a group of control registers located at 4. The microprocessor can load control parameters for the next pattern into these control registers while the current pattern is being moved from raster pattern memory 38 to strip buffer 40. After the microprocessor loads all control parameters, it sets the synchronization bit. The sync bit starts the pattern movement process. After the pattern has been moved, the raster image generator provides a signal to the microprocessor indicating that its control registers can be reloaded. The data transferred from the microprocessor are parameters such as a start scan, a start pixel, the number of scans per pattern, and the number of pixels per scan. The number of scans per pattern and the number of pixels per scan give the size of the pattern.

In addition, the pattern address transferred from the microprocessor indicates that the pattern to be placed on the page is raster.
Indicates where in pattern memory 38 it is located. The synchronization control function of pattern movement control circuit 44 keeps the microprocessor program and pattern movement process in step with each other. As shown in FIG. 4, the raster image generator includes three large components 40, 42.
, 44 exist.

Raster pattern memory 38 holds the raster pattern to be placed on the page. It includes character patterns, raster image fields, patterns that generate rules or lines. The user can see how the printer provides a page-sized raster buffer. The page will be created during this raster battle. In reality, raster image generators use strip buffers that cover only a small portion of the page.
). Pages are created in this strip buffer 40 and simultaneously sent to an imaging device or storage device (disk). Pattern shifter 42 correctly positions each pattern scan line along the scan relative to the word structure of the strip buffer. The pattern movement control circuit 44 stores the pattern in the raster pattern memory 38.
The data is transferred from the signal to the strip buffer 40 via the pattern shifter 42. Then the data is
Printed from a strip buffer. Printers can print pages in very flexible formats.

A page layout showing various formats is shown in FIG. For example, a line of data 50 at the top of the page is printed across the scan direction, while similar data 51 is printed along the scan direction. In addition to text data, the printer can print raster image data, such as image data 52, anywhere on the page. Vertical ruled line 54 or horizontal ruled line 5
Ruled lines such as 6 can also be printed with this printer.
The pattern is formed by a series of scans along the page, and each successive scan is displaced so that the entire page can be printed in successive scans. The size of the characters is limited from a particular location, such as the start scan, start pixel located at corner 58 of A in FIG. The size of the pattern along the scanning direction is limited by the number of pixels, and the size of the character perpendicular to the scanning direction is
Limited by number of scans. The character pattern is 32 pixels or 16 pixels per scan. If a character requires more than 32 pixels, the character is composed of multiple subpatterns that are processed by the hardware as multiple separate characters. Any pattern has a maximum number of scan lines limited by the size of the strip buffer. For example, if the strip buffer can store 128 scan lines, the pattern can have a maximum of 64 scan lines. This is because while one pattern is being printed from the strip buffer, the next pattern is being loaded into the strip buffer.

Character patterns are stored as a group of related characters of the same size and style called fonts.

Fonts are stored in 2000 byte blocks of storage, and their patterns do not span boundaries between 2000 byte blocks. Each font has a font index. This index contains information related to all the characters in the font, such as baseline offset, as well as information unique to each character. The microprogram that prepares the page for printing uses the above index to convert from EBCDIC codes to pattern addresses, and also for other controls necessary to form the page. . index is 2
It consists of 56 entries, of which only 254 codes can be used as printable patterns. This is because one code is used to exit to the control sequence and the other code is used to specify a blank. A font index is maintained in the control store for each font active on the current page. The raster image is decomposed into square subarrays.

These subarrays can be processed by the hardware just like character patterns. A typical image subarray is 32 pixels by 32 scans.
The patterns used to draw the rules are created in 32x32 squares, and those patterns are used to draw both along-scan and cross-scan rules. The first pattern has one black pixel per scan line. Each subsequent pattern increases the number of black pixels per scan by one. The last pattern has 32 scans per scan.
All pixels are black. The complete set of ruled line patterns is 3
It consists of two patterns and requires 4000 bytes of raster pattern memory storage. The raster image to be printed is created in a strip buffer.

In this embodiment, the strip buffer covers only a small portion of the page. This is because the strip buffer contains only 128 lines. This strip buffer capability typically provides data that prints only a portion of the page according to its resolution. The conceptual operation of cylinder 70 is
This is shown in FIG. On cylinder 70, scan line 127 wraps around to scan line 0. As the strip buffer rotates across the plane of the page being printed, printing results from scan lines filled and prepared for printing. Data on the scan line at the point of contact is sent to an imaging device. As each scan line is printed, the cylinder rotates one scan line position. Since each scan line position in the strip buffer is used many times during the printing of a page, after sending the data to the imaging device, that position in the scan line is set to zero. A
The entire character pattern, such as 8O, is loaded onto the scan line 74, which is cleared after printing. The loading process begins at the current starting scan line, indicated by dotted line 78, and moves to cleared area 74 to where data is being sent to the printer, as indicated by arrow 72. The current start scan line 78 is prevented from moving closer than 64 scan lines from the print scan, so that even the largest character patterns can be loaded without interfering with the printing process.
If the data distribution on the page causes the start scan to be 64
If more than one scanning work area is entered, operation must be temporarily halted and the printer must wait until it has generated enough scan lines. By doing so, 64 scanline work areas are saved. On the other hand, the printer must not be able to keep up with the starting scan. If the distribution of data on the page causes the printer to catch up with the starting scan, an overrun condition occurs. Overruns must be avoided. This is because synchronous printers, such as electrophotographic printers, print defective pages. Overruns can be avoided by sending the raster image to an accumulator before printing. Strip
The buffer accesses a pair of 32-bit words at a time.

The pattern can be 16 or 32 bits per scan and can be located at any pixel within a scan. The purpose of the pattern shifter is to correctly position the pattern with respect to the 32-bit word structure of the strip buffer. Before explaining the operation of a pattern shifter, it is necessary to understand the structure of a strip buffer. Referring to FIG. 5, strip buffer 40 has an A portion 60 and a B portion 62, each having a width of l words. Both the A section 60 and the B section 62 are accessed each time the strip buffer is read or written, and the input and output registers are treated as one unit. A and B parts are separate but cooperating address registers 6
It has 4,66. In that case, A address register 6
The address of 4 is equal to or greater than the address of B address register 66 by one. Pixels in one scan line have an arrangement of 32 bit words.

The 32-bit words are interleaved between the A and B portions of the strip buffer as shown in FIG. The input to pattern shifter 42 is 3
It is 2 bits wide and the output of the pattern shifter is 64
Pixel 0 of 0 input, which is the width of bit, is shown in Fig. 7A and 7.
As shown in Figure B, the output can be positioned at any of the 64 pixel locations.

The next 31 pixels of the input are then set to 0. All other pixel locations of the output are set to zero. If input pixel 0 is shifted less than 32 positions as shown in FIG. Setting the address will ensure proper writing to the strip buffer. If input pixel 0 is shifted by 32 or more positions but less than 64 positions, as shown in Figure 7B, some of the following pixels will drop out of the end of the pattern shifter. Instead, the pixels from the pattern shifter are rewound to lower order output pixel positions as if they were placed modulo 64. The lowest order 6 bits of the 0-start pixel parameter that are correctly written to the strip buffer by setting it larger than The presence of a 1 bit in a position indicates that the address of part A is greater than the address of part B by one. Whenever data is written to a strip buffer location, the contents of the strip buffer at that location are read and before it is written back to the strip buffer.
0 is logically combined with the new data by the 0R circuits 46, 48. Such processing is necessary in order not to destroy the pattern previously located into the 8 bytes in the strip buffer. provides automatic overstrike capability for characters as shown at 59 in FIG.
ng) Data from the strip buffer goes to parallel-to-serial converter 69.

The data is converted to a serial bit stream on line 71 (FIGS. 4 and 5) in parallel-to-serial converter 69. The serial bit stream is directed by switching means 82 and 84 over line 89 to control imaging device 32 (FIG. 2) for printing or to an accumulator 90 for temporary storage. . Accumulator 90
includes any suitable memory having a volume capable of storing the entire bit image of a page, so that even complex pages can be printed.

In an embodiment, the accumulator 90 is monolithic.
It's memory. As shown in the following table, switch 82 is set to position a and switch 84 is set to position b.
data can be written to the accumulator via the 0R circuit 86. switch 8
By setting 2,84 in position a, the accumulator data is OR-combined with the new data on line 71 and printed by the 00R circuit 88, which allows additional data to be OR-combined into the accumulator. In order to Not used. Pattern movement control circuit 44 moves the appropriate number of scans for the pattern from the raster pattern memory (RPM) to the pattern shifter, positions them correctly along the scan lines and places them in the strip buffer.

The pattern movement control circuit is associated with three types of hardware data formats. In the first type, 32 RPM
A bitword carries one scan line of a 32 pixel pattern. Scanlines are taken out one at a time and the RPM address is incremented as each scanline of the zero pattern is processed which is passed directly to the pattern shifter. Each word has two 16-pixel character scan lines. The first 16 pixels are left aligned and passed through the shifter; the remaining pixels into the shifter input are set to O. These pixels is written to the strip buffer, the pattern movement control circuit moves the 16
The 0 RPM address that takes pixels, left-aligns them, blanks the remaining input pixels, and writes them to the next scan line in the strip buffer increments as each pair of scan lines in the pattern is processed. be done. In the third type of data format, each word of RPM holds two scans of subarrays for low resolution raster image data.
The first 16 pixels are processed first. Each pixel is doubled, thereby extending this data to the entire 32-pixel width of the pattern shifter input. Then these 32
After doubling the size of the first halfword from 0RPM which is written twice into the strip buffer on successive scan lines, the pattern movement control circuit performs the same operation on the second halfword from 0RPM. The address is
The low resolution pattern is incremented as each pair of scan lines is processed. The pattern shift control circuit adjusts the offset of the pattern shifter to correctly position the pattern scan line relative to the word structure of the strip buffer. Select the correct word along the scan line in the strip buffer. If necessary, it is possible to
Offset the addresses in the two parts of the buffer from each other. The pattern movement control circuit advances the scan position in the strip buffer as each scan is placed in the strip buffer. Additionally, it decrements the scan counter as each scan line is transferred to the strip buffer, and when the scan count equals zero,
Finish pattern transfer. Furthermore, the pattern movement control circuit handles data movement from the strip buffer to the imaging device. In FIG. 5, pattern movement control circuit 44 includes a number of control registers 91-96.

As a preparatory step for each character move operation, data is loaded into these registers by the microprocessor.
The start scan is loaded into register 91 from the scan table. The pattern address table is in register 9.
2, give the data of the start pixel and register 93
provides scan number data for register 94, provides pixel number data for register 94, provides certain data for mode control register 95, and provides RPM address for register 96. Mode control register 95 provides a control signal to enable dual dot control circuit 97, if desired. A raster image of the page is generated in the 128 scan line area of the strip buffer at the same time that the page is being printed.

This dynamic process dictates that all raster patterns starting on the same scan line must be placed into the strip buffer before proceeding to raster patterns starting on the next scan line. 0 means that the raster pattern must be processed in starting scan line order as the page is printed. Data generated by the host application program is not guaranteed to be in ascending starting scan order. In some cases, the data from the host processor is in the correct order, in which case a bit in the associated channel control word will tell the printer this. In this case, the printer does not process the data to put it in order, it simply prints the data in the order it was transferred on the channel. However, in many cases, data is not sorted in this order. For example, in text line 51 of FIG. 3, the first character to be printed is H.

However, the sixth character 53 on the line represents a character with a superscript.0Although this character is the sixth character in the line, it is printed second. Because it is character 5
0 because it starts on the scan line preceding 5. The characters 55 both start on the same scan line. Character 57 represents a character with a subscript, so it starts on a later scanline. Smaller character 61 also starts on this scanline. This printer is designed so that when a page is printed, the raster pattern is set to the start scan. Provides an effective and flexible means of ensuring that lines are processed in order.

The flexibility of this approach is that it doesn't matter what order the data comes in. This flexibility allows the printer to print data in two directions on the page, and allows it to print data in any direction on the page. Allows you to shift the base line in time. The method developed for this printer is
A collection of 0 list heads using linked lists, one list for each scan line in the page, is called a scan table. The list head for each scanline points to one of two locations. If there is no raster pattern to print starting on that scanline, it can point to the list head for the next scanline, or it should start on that scanline. There is a second table used during the printer classification process that can indicate table entries for patterns. This table contains one entry for each character, each segment of a rule, and each subarray of raster images printed on the page. This table is called the pattern address table.
An example of a pattern address table entry for the page format shown in Figures and Figure 11 is as follows. The position of the character along the scan is limited by the start pixel, the size of the character is limited by the number of scans and the number of pixels, and the address of the graphic character pattern is defined by the RP.
M address.

Pattern address table entries can also be prepared for other types of print data such as single pixel raster data and two pixel raster data.In addition, linguistic data such as Kanji can also be prepared using this method. 0 entries that can be processed are appended to the end of the pattern address table as they occur in the input stream; each entry is needed to place the associated pattern in the appropriate location on the page. When a request for a pattern occurs in the input data stream, including all information such as starting location, pattern size, address, etc., the first task is to determine on which scan line it starts. It is.

The entry for it is then concatenated to the list head for that scanline. The entry is then concatenated to one of two locations. It starts on the current scanline. It can point to the previous component of the list containing all raster patterns, or when it is the first entry to occur for the current scanline, it can point to the list head for the next scanline. can be given instructions. The process of preparing a page for printing is
The result of the page preparation process, which consists of building the pattern address table, updating the scan table, and loading the scan pattern memory with the new font and image subarrays required for that page, is a linked list. This linked list allows all the patterns on the page to be processed in the order in which the scanlines progress. When printing begins, the characters are taken one list at a time and the patterns are stored in the strip buffer. Two tables of instructions are created in the control store and placed there. These two tables are interconnected by a branch operation. The first table is the scan table and Called.

There is one entry for each intervening scan line.0 All characters to begin on that scan line are concatenated to this entry. The manner in which the pattern address table is created is determined by the printing direction. Figure 8 shows the case of printing along the scan lines. The text is then shown in the page layout of Figure 9. It runs parallel to the scan line. First, a scan table is prepared. This scan table defines the characters that start on that particular scan line. Scan lines 0 and 1 are blank, and scan line 2 is blank.
Above there is a branch to address P+O.0 Address P+0 has a proportional along (PAl,) . The command is 0 This command results in the printing of the letter A. The displacement of pixels along its scan line comes as a parameter of the command.

The processor then goes to the next instruction at address P+1, which causes the printing of the letter L. Characters 0, N, G
The operation is the same for 0. A branch (BR) instruction occurs to return to the next line in the scan table. 0 This process continues until a line of text is printed. Generally, text data requires a large number of scanlines, but for clarity, only a few are shown here. ~ The AX0S scan line of FIG. 10 is started in the same manner as FIG. 8.

However, in scan 2, a branch to address P+10 occurs. The instruction AC(E) here is the word EXA
0 word SCA which is an instruction to print the letter E of MPLE
To print the letter S of N, a branch is connected to the AC(S) instruction, and another branch is connected to the AC prisoner instruction to print the letter A of word ACROSS. A branch from this instruction takes 0 to the next scan line in the scan table.
The ACR0SS instruction (AC) has a branch address field to generate a branch. Therefore, by using the above two table structures, two directions of text data can be combined on the same page. 0 As each character in the text stream is received, it is placed at the end of the pattern address table.

Its scanline number is calculated and it is concatenated with the appropriate list-0. If it is across scan text, the concatenation is done by changing the address in the scan table, and branching.
Including adding an address. But if this is ALONG
With scanned text, only the first character of each line requires modification of the scan table, intermediate characters are linked by order in the pattern address table, and the last character requires an additional branch instruction. shall be. text 2
Two orientations can be done using essentially the same linkage, and different orientations can be done in the same scan and pattern address tables; providing multiple scan and pattern address tables for the same page. It is also possible to first write a subarray of characters or images to the strip buffer according to the first scan table, and then control is passed to the second scan table and the strip buffer is written accordingly. In FIG. 5, the 0R circuits 46 and 48 at the strip buffer entrance superimpose and write a new character or image on top of the character or image already written in the buffer. This is not only useful for special overlays such as those shown at 49 and 59 in Figure 3, but also for editing and combining data from different sources on different parts of the same page. Give convenience.

The manner in which the entry of the pattern address table is connected to the list head of the scan table and the example of the entry of the pattern address table were shown above, but another method is to connect each entry of the pattern address table with a scan line. Add a number field and first enter the pattern, address,
0 Incoming text that can be assigned a scanline number (the number of the scanline in which the character should appear) to each data character in the table, and then reorganized by scanline to the list head of the scantable. The structure of the present invention is to arrange data as code-form data in scanning order, to create a table by attaching control information such as size and position to each character, and to write a dot pattern to a strip buffer in accordance with the table. provides a printer that is flexible in placing the desired characters at the desired size and in the desired orientation regardless of the order of arrival of the incoming text characters. I will explain about it.

The microprocessor is closely associated with the process of printing pages.

The microprocessor loads parameters into external registers that control the placement of each pattern on the page. The hardware then moves the pattern from the RPM to the strip buffer based on the parameters loaded into this control register. The control registers are start scan,
Start pixel, number of scans in pattern, pixels per scan (
16 to 32), the 0 synchronization signal, which specifies whether doubling of size is required for 16 patterns, the RPM address where the pattern is stored, the synchronization signal, etc., is used by the pattern movement hardware and microprogram. synchronize the pace of the There are two levels of control registers, and when a pattern is moving from the RPM to the strip buffer using one control register, the microphone processor transfers the next character to the other control registers. You can load movement parameters for.

The last step performed by the microprocessor during register loading is to turn on the print ready indicator. Before the hardware begins moving to the next pattern, it checks the print ready indicator to see if all parameters have been loaded. For small characters and lines, pattern movement may be finished before the microprogram loads the next set of parameters. If the hardware has to wait until the ready-to-print indicator turns on, pattern movement will begin as soon as the indicator signal is received. When the pattern movement process is complete, the processor will The process is notified that it is ready to be reloaded. While a page is being printed, the microprocessor is also given a signal after the printer completes each scan line, so the microprocessor can keep track of where on the page the printer is printing. Therefore, when the microprocessor enters a halt state to avoid zero overruns, it can force a halt to the character movement process to avoid printer position overruns if necessary. This ends when the printer has advanced enough to signal that pattern movement can resume. If a raster image accumulator is used to mix the 0 data with the print data, the microprocessor , the microprocessor receives a signal at the end of each data transfer from the accumulator and controls the next data transfer.The microprocessor also processes the process of loading print data into the raster image accumulator, and the process of loading print data into the raster image accumulator, as well as the process of loading print data with data already stored in the accumulator. The operation of loading print data into the 0 accumulator, which controls the process of combining it with print data, is similar to the printing operation, but the print data is loaded into the accumulator using the lower circuit in Figure 5 instead of the imaging device. go. The printer is connected to an IBM System/370 channel. It is controlled by the host system by extending the channel command. There are four different channel commands.

These are write commands, "load and delete" commands, status commands, and control commands. Write commands are used to transfer data from data processing unit 16 to printer 12. Two types are for printing text and the other two are for imaging.The write text command allows the printer to accept data ranging from a few characters to an entire data set. The text data to be prepared is transferred by a series of text write commands. Each text write command transfers one block of text data and the control code contained therein. The image write control commands are: Prepare the printer so that it can receive one image rectangle.

Image data is transferred by a series of image write commands. These image write commands immediately follow the image write control commands. Whether text or images, the control commands are 0 data that orient the data on the page. is oriented using an XY coordinate system, and for normal printing, the origin of the Before receiving a write command, the direction of the text on the printed page, the units of movement along or between lines, the characters for creating blank spaces, and the characters for exiting control sequences must be known to the printer. These parameters are: Limited by text write control commands. This control command transfers an 8-byte control record. The first 2 bytes set the text direction, the next 4
The bytes set the width and the last two bytes set two special character codes.0 Set the text direction.The purpose of the two bytes is to set the line direction and line order of the text given by the text write command that follows. is to set 0
The printer limits two combinations of line direction and line order. One of them is Upright.
and the other one is Sideways.
), which is 0, defines the row direction. Lines of text are considered to grow in the direction in which successive characters are added, so it is called the line direction. o The second byte determines the line order. A page of text can be thought of as growing in the direction in which successive lines of text are typically added; this direction is therefore called line order. Row order is always perpendicular to the row direction. 2
Each of the three orientation bytes has four directions: +X, +Y,
Specify one of -X or -Y.

These directions are represented by 0,60,120,180 and encoded as hexadecimal 00,3C,78,B4. Therefore, for an upright page, the control bytes are +X and +Y Hexadecimal number 00,3C representing
For a sideways page with 0, the row direction is -Y and the row order is +X.0 where the control bytes include hexadecimal B4 and 00. The user of the text write command may be indifferent to X and Y. For uprights, the line direction is +X, but for sideways it is -Y 0. Therefore, by setting the first two bytes of the text write control command, the user can: Sets how readable text should be printed by the printer in the XY coordinate system. The built-in control functions of the write text command will be explained later.This built-in control function positions the text along the two directions given by the control bytes described above. is the normal reading direction on the page. The line direction is horizontal and new characters are added to the right. The zero line order is vertical and new lines are added continuously down the page. Positioning information along the zero line direction is inline. (1) Given in units. The purpose of the following control byte is
A 01 pixel is a single black or white dot, which defines how many pixels constitute one I unit. The printer prints 2 per 2.54 cm in the X and Y directions.
01 unit printed at a rate of 40 pixels is 1 pixel or 2
Byte 3 of the 0 text write control command, which may be defined to be a pixel or any number of pixels up to 255 pixels, is an I
The 0 byte 5, which specifies the number of pixels in a unit in binary representation, is the 0 text, which specifies the number of pixels in a base line unit in binary representation.
A stream consists of a series of 8-bit character codes.
Two of the 256 possible character codes are used for special purposes.

That is, they cannot be used to print characters.
One is a character code used to create a blank space (SP) and the other is a character code for exiting to a control sequence (ESC). EBC
In the DIC text stream, hexadecimal 40 is interpreted as a blank space 0. However, other codes can be used as the printer's space character, in which case the code is included in byte 6 of the control command. Byte 7 contains a 1-byte parameter that causes an exit to the control sequence. 0 The contents of byte 7 must not be the same as the contents of byte 6. In the example of Figure 11, the blank space code (SP) is hexadecimal 40, and the escape character code (ESC) is hexadecimal 2.
7. Most printers currently in use transmit one printed line for each channel command word used. The text may contain any string of 8-bit characters. All hexadecimal patterns, except for SP and ESC patterns, are converted for printing by the font index table selected by the control code.
A series of bytes consisting of hexadecimal bytes.

The first byte is the escape character code ESC, which in this example is hexadecimal 27. The second byte limits specific control codes. There are some control codes that are transferred along with the text data as built-in commands by the write text command.

These control codes can be classified into three groups:
A group of inline codes that control the movement of characters along a text line ((), a group of codes that control the movement of a base line down the page, and a group of other codes. 0 Inline movement involving code refers to movement in or along lines of text.

Therefore, a spacing operation is an inline movement. The inline displacement is measured from the end of each consecutive character retreating. In the two orientations utilized by the printer of the present invention, the inline reference edge is the left edge of the page when the page is placed in the reading direction.0 The inline edge setting control code is the left edge position. 0 This is a 2-byte parameter that causes the first line of text and each new line caused by the end-of-line control code to start at the current edge. Code included in the inline code group includes the following: The letterspace set control code sets a 0 blank value to change the number of pixels to be skipped after each printed character; the control code specifies the number of units to be skipped when a blank space character is found. do. Inline absolute movement code is used to move to a specific horizontal position on a line measured from the left edge of the page. Inline relative movement control codes are used to move a line to a new horizontal position. The line end control code marks the end of a line of text. The printer assumes that subsequent text begins at the left edge of a new line. The following code set is for baseline movement: .

A base line is usually defined as an imaginary line on which letters and words are to be placed; thus, the letter S is placed on the base line, and the circular part of the letter p is placed on the base line; The downward projection is below the base line.0 The displacement of the base line is measured from the edge of the paper, and lines of continuous text usually recede in the line order direction from the edge of the paper.0 This code group The 0 base line edge set control code specifies the location of the first base line on the page. This control code contains a 2-byte border that defines the first line of text on each new page. This is a parameter, and control of the text write command starts on this baseline. The Baseline Spacing Set code determines the amount of space that the end-of-line control word causes between printed lines. The base line absolute movement control code is used to move the base line to a specific position measured from the lowest edge of the page.The base line relative movement control code is used to move the base line a specified distance from the current base line position. 0 used to move lines This control code moves the base line up and down the page. The base line temporary movement control code temporarily shifts the base line on which the next character is printed up or down. The last built-in control code group includes a code for drawing a ruled line and selecting a font.A ruled line is a horizontal or vertical line of any height or width.

They are useful, for example, when creating a table with many columns separated by bold lines. For an example of the use of text data with built-in control codes, see Figure 12.0 Text stream is the word FLEXIBL
EBCDlC code of E followed by a standard space code of 40 hex followed by the word PRINTER
The sign of 0 and the hex 27 escape character, hex 27, the control code of the 2 bytes, hex 27C6, represents the built-in end-of-line control code. Data continues to the next line.

Then there is the 02 byte of hex 27C5, in which there is 01 hex 27C500E0, which instructs the first character of the next line to be set back a certain distance from the current left edge.
The hexadecimal number 00E0 (decimal 240) indicates that this retreat distance is 240 pixels (i.e. 2.54 cfn) The zero data stream continues until the end of the second row. Two sample lines printed are shown: 0 If the center of the word FORMAT is the center of the word group FLE
This example will be easier to read if you align it to the center of the XIBLEPRINTER.
MI) By changing the parameter from 240 to 160 (i.e. from hex 00E0 to hex 00A0), instead of 2.54 cm as shown in FIG.
It could be displaced from the edge by two thirds of it.
When this corrected data stream is printed, the word FORMAT is the word group FLEXIBLEPRIN.
The 〇 font whose center is aligned with TER is a collection of character patterns, from which characters to be printed are selected.

The 96-character font consists of 26 uppercase letters, 26 lowercase letters,
It may consist of 34 special symbols including 10 numbers and punctuation marks.

Each typeface is usually named by its size, style, and weight, such as 14 point (size), press Roman (
〇 Printers are designed to print images as well as text data. 〇 Images can be scanned in many ways. The 0 image may be generated by a computer or transferred to the printer as binary bit image data (i.e., as black and white dots in a scan line sequence); the 0 image control information is It is contained in a 30-byte image control record, which is transferred to the printer by an image write control command.

The image itself may require multiple data transfers of 2.048 bytes and will be transferred by subsequent image write commands. Image writing data received by the printer is interpreted as a series of compressed or uncompressed scan lines.

Each uncompressed scanline is assumed to be of equal length. - The series of scan lines are assumed to form an image rectangle when taken together. One side of the rectangle is counted in pixels and the other side is counted in scan lines.The first two bytes in the image control record represent the length of one scan line in pixels. This count value is written in binary. The length of the scan line transferred uncompressed by the image write command is an even number of doubles.
A zero or binary pixel count value that is required to be a byte must end with a hexadecimal O. Bytes 2 and 3 define the width of the image rectangle, in which the scanlines in the image are counted in binary.0 Byte 5 is
The decompression selector, a code of 01 hex indicates that the image data is uncompressed, and a code of 01 hex selects the printer's special decompression algorithm. It is a device that creates a digital electronic image of whatever is being scanned. 22 (177! x 28cT) encoded with black and white dots
For the entire n page, there are 673.200 bytes of electronic image. In order to reduce this number, compression of the electronic image must be performed by some type of scan generator. The compressed image can be represented by a portion of the original data. Reducing data size can ease host system data storage and data transfer requirements.0 Data storage and data transfer economics are the primary reason for compressing and decompressing images.0 Human readability Most of the page contains a lot of white space, and when a normal sheet is scanned, a long string of white dots is encoded with a special white dot code and its white dot count. This method, called 0-run length coding, is just one of many methods used, which allows many bits to be saved by compression methods that represent long scan lines. The input image is
The 0 bytes 6 and 7, which can be trimmed to create a small rectangle for printing, represent the starting pixel trim count in binary.

The trim count represents the number of pixels removed from the beginning of each scan line.0 Bytes 8 and 9 represent the ending pixel trim count in binary. This trim count represents the number of pixels removed from the end of each scan line. The 0 bytes 10 and 11 are utilized as the starting scan trim count for the image data. Bytes 12 and 13 are included in byte 14, a zero pixel count scaling factor that defines the end scan trim count for image data. The printer hardware is
2.54Cr 240 scanning lines are printed on a 1L square paper area, and each scanning line contains 240 bits of data.
That is, there are 57,600 bits in a square area of 2.54 (V7!). In some applications, such high resolution is not necessary or achievable. is reduced to a lower resolution and the number of bits per 2.54 square is reduced by a factor of 4, i.e. 120 scan lines per 2.54 square and 120 bits per scan line.The actual printing hardware is , still prints 240 pixels.The 120 pixel case is handled by repeating each low resolution data bit twice.
Similarly, each scan line with doubled data bits has 2
Either print the 0 image that is printed as is, or
Two scaling factors can be used to specify whether to double the scaling. Byte 14 is coded as hex 01 to print as is, and coded as hex 02 to double the number of pixels. In the latter case, each scanline is is also twice as long.

[Brief explanation of drawings]

1 is a basic block diagram showing how a printer according to the invention is connected to a data processing unit via a main channel; FIG. 2 is a block diagram of the basic components that make up the printer of FIG. 1; 3 is a diagram illustrating the printing flexibility of a printer according to the invention; FIG. 4 is a block diagram of the basic components that make up the raster pattern memory and raster image generator of FIG. 2; and FIG. 5 is a diagram of the printer. a block diagram showing the data flow of the control means;
Figure 6 is a diagram showing the conceptual operation of a strip buffer;
7A and 7B are diagrams showing the operation of the pattern shifter, FIG. 8 is a diagram of a specific embodiment of the character classification means when printing text data along a scanning line, and FIG. 9 is a diagram showing the operation of the pattern shifter. A diagram of a page printed along a line, FIG. 10 is a diagram of a specific embodiment of the character classification means when text data is printed across a scanning line, and FIG. 11 is a diagram of a page printed across a scanning line. 12 shows the contained control and text data, and FIG. 13 shows the layout of the scan lines stored in the strip buffer.

Claims (1)

[Claims] 1. An apparatus for raster scan printing of data in response to input data consisting of character data and control data, comprising memory means for storing graphic coded data corresponding to said character data, and corresponding to at least a portion of a printed page. buffer means having a capacity for editing the graphic coded data; table means for sequentially connecting the input data according to the point in time when a predetermined portion of the corresponding graphic coded data is scanned; The table means receives the input data in the specified order, and in response to the input data, limits the character position designation information on the print page and the size of the characters on the print page for the character data of the input data. a first control means for generating size information to be displayed and address information specifying a position of the graphic coded data in the memory means; and a first control means for generating size information, size information and address information output from the first control means. second control means for responsively transferring said graphic coded data from said memory means to said buffer means; and second control means responsive to said graphic coded data in said buffer means for transferring characters represented by character data to a print medium. and third control means for sequentially printing on the data.