JP2500634B2 - Page printer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a page printer, and more particularly to a page printer using a band buffer.

[0002]

2. Description of the Related Art A conventional page printer has a character code,
The dot data obtained by drawing each image and figure is developed in the page buffer, and the data in the page buffer is sent to the printer engine for printing at the laser scan timing of the printer engine.

In this conventional page printer, it is necessary to store one page of dot data in the page buffer, and the memory used for the page buffer requires several megabytes depending on the size of the paper and the resolution of the print output. Met. This is a considerably large capacity, which has been an obstacle to reducing the cost of manufacturing a printer.

In order to solve this, about 1/4 of the memory of the page buffer is used to send dot data to the printer engine for printing during the drawing process of print data, and the memory is transferred to the printer engine. A method of repeatedly using the memory is adopted in which the sent dot data is erased and the dot data by the drawing process of the next print data is written in this memory. Most of the printing by the printer engine is a raster scan type, and since reading and printing are performed line by line, dot data is also written line by line in this memory. This memory is called a band buffer because it handles dot data by separating it from one line.

In the conventional page printer utilizing the band buffer, when the printing speed of the printer is faster than the speed of rendering the drawn data in the band buffer, the dot data which is not fully developed in the band buffer is printed by the printer. Since it was sent to the engine, there was the inconvenience that there was a missing character in printing.

When this overrun error occurs, a part of the text buffer area is allocated to the video band buffer (VBB) to automatically increase the VBB capacity VB.
By providing the B area changing means, a method for increasing the initial expansion amount and performing normal printing during reprinting (for example,
Japanese Laid-Open Patent Publication No. 02-052763), a printer that performs thinning processing to avoid character loss (for example,
JP-A-63-302053).

Further, according to the printing method using these band buffers, the drawing processing of the print data in the band buffer and the data transmission from the band buffer to the printer engine cannot be performed at the same time, and the horizontal synchronization signal of the printer engine is It was necessary to finish the drawing process during the sending, and this limitation of the development time was one of the causes of the occurrence of character loss.

Therefore, as shown in FIG. 2, there is a method in which a plurality of band buffers are installed, and the printer control unit sequentially clicks and selects each band buffer to perform drawing processing and sending to the printer engine. Since printing is performed continuously, the print processing speed is improved and it is also effective in avoiding character breaks. However, by using a plurality of band buffers, there has been a problem that the conventionally used method of overrun error detection cannot be used.

[0009]

However, in the above-mentioned conventional example, although the good operation and effect of avoiding the character loss can be obtained by accurately recognizing the occurrence of the overrun error, the speed of the expansion of the print data is It is difficult to predict because it depends on complexity, therefore, it is technically difficult to accurately recognize the occurrence of an overrun error, and it is difficult to say that typographical characters are accurately avoided in the conventional example.
In order to avoid punctuation, first of all, it was necessary to accurately recognize the occurrence of an overrun error.

Further, in the conventional example, even if a character loss is detected, it is not displayed externally, so that there is a disadvantage that the printer operator may overlook the print disorder due to occurrence of character loss.

[0011]

OBJECTS OF THE INVENTION The object of the present invention is to improve the disadvantages of the conventional example, and in particular, when characters are missing on printed matter,
It is an object of the present invention to provide a page printer capable of surely detecting even a printer having a plurality of band buffers and notifying the printer user.

[0012]

The present invention is directed to a drawing unit for drawing print data received from a host device into dot data and writing the dot data into a band buffer, and a printer control for transmitting the dot data from the band buffer to a printer engine.
Section and horizontal sync signal output from this printer control section
The dot data drawn in the band buffer based on
It has a printer engine for printing out. Only
Also, it features in the printer controller, a write counter for counting the number of writes to the band buffer of the dot data, and a read counter for counting the number of output times of the horizontal synchronizing signal
At the same time, the read counter count number is compared with the read counter count number, and the number of lines to send an interrupt signal to the printer control section when the read counter count number exceeds the write counter count number. and it features a recognition unit.
Moreover, when the printer control unit receives an interrupt signal sent from the line number recognition unit, it has an error output function of calling an error message provided in advance in the page printer and externally outputting the error message. ing. This aims to achieve the above-mentioned object.

[0013]

When the print data is received from the host device and the print data is drawn into dot data by the drawing unit 1, the dot data is first written in the band buffer 2. At this time, every time one line of dot data is written, the printer control unit 9
Thus, the writing counter 6 in the caret recognition circuit 5 is incremented.

The dot data in the band buffer 2 is read line by line in the printer engine 4 in accordance with the laser scan timing of the printer engine 4. The read counter is incremented by the printer control unit each time the printer engine reads data. At the same time that the data in the band buffer 2 is sent to the printer engine 4, writing to the band buffer 3 starts.

Thereafter, the printer controller 9 clicks the band buffers 2 and 3 to repeat writing data into the band buffer and reading data from the band buffer until the drawing-processed data is read.

The line number recognition unit 8 compares the count number of the write counter 6 with the count number of the read counter 7, and continues printing while the write counter 6 has a large count number with respect to the read counter 7, and prints all data. After printing, the line number recognition unit 8 resets the counters 6 and 7.

Further, when the count number of the reading counter 7 becomes larger, the line number recognition unit 8 causes the printer control unit 9 to operate.
In response to this, an interrupt signal is input, and the printer control section 9 displays an error message on the operator panel 10 that a character loss has occurred.

[0018]

Next, an embodiment of the present invention will be described with reference to the drawings.

The drawing unit 1 draws the print data received from the host device into dot data, and writes the dot data line by line in the band buffers 2 and 3 selected by the printer control unit 9. This writing is performed at the timing of the write signal from the printer control unit 3. The printer engine 4 reads out dot data from the band buffers 2 and 3 based on the horizontal synchronizing signal of the printer control unit 9 and prints out the dot data.

The row number recognition circuit 5 includes a write counter 6
And a reading counter 7 and a row number recognition unit 8 for recognizing the number of writing to the band buffer and reading from the band buffer for each row.

The write counter 6 counts the number of times of writing dot data in the band buffers 2 and 3 in units of one line. The write counter 6 is incremented every time the printer control unit writes one line of dot data from the drawing unit 10 to the band buffers 2 and 3. The reading counter 7 includes the band buffers 2 and 3 to the printer engine 4
The number of readings that match the laser scanning timing of is counted line by line. Specifically, the reading counter 7 is incremented with the transmission of the horizontal synchronizing signal from the printer controller.

[0022] The number of rows recognition unit 8 compares the count of the number of counts and readings out counter 7 of the write counter 6. When the number counted by the read counter 7 exceeds the number counted by the write counter 6, an error flag is set and an interrupt signal is sent to the printer controller 9. This error is an overrun error. After printing out all the print data, the write counter 6 and the read counter 7 are reset.

The printer control unit 9 drives and controls this printer, such as drivingly controlling the printer engine to print out dot data. The printer control unit 9 externally outputs an overrun error by an interrupt signal from the line number recognition unit, and thus calls an error message related to the overrun error from the error message table stored in the memory of the printer device. .
Here, since it is the display output to the operator panel 10 that is installed in addition to the page printer, the printer control unit 9 transmits the error message to the operation panel.

Further, the printer control section transmits the horizontal synchronizing signal to the band buffer at the laser scanning timing of the printer engine and increments the read counter 7. Further, when the first band buffer 2 becomes full, the printer engine is started to start the print output, and at the same time, the second band buffer 3 is clicked and the dot data drawn by the drawing unit 10 is stored in the band buffer 3. Start storing. This band buffer click is repeated until all print data is printed out.
Further, a write signal is transmitted to the drawing unit 1, and the write counter 6 is incremented each time dot data is transferred from the drawing unit 1 to the band buffers 2 and 3 line by line.

The operator panel 10 is a simple input means for setting the printer and the like.
It has a relatively small display panel for displaying errors and the like. The error display of the printer control unit by the interrupt signal from the line number recognition unit is performed on this panel. By displaying the occurrence of character loss due to an overrun error on the operator panel, the user of this printer can be notified of the occurrence of character loss quickly and reliably.

In the above-mentioned embodiment, the occurrence of an overrun error is detected by detecting the occurrence of a character loss by comparing the number of times of writing to the band buffer with the number of times of reading from the band buffer, and this is further displayed externally. To do. Therefore, even if the printer has multiple band buffers, it is possible to reliably detect the occurrence of character loss.Also, the printer user must check the error displayed on the operator panel and re-create the printer memory. It is possible to provide an excellent careless character recognition circuit which is a basis for correction when a careless character occurs such as setting.

The external output of the overrun error is
Not only the operator panel but also a higher-level device of this page printer may be transmitted and displayed on the display of the higher-level device.

[0028]

According to the present invention, as described above, according to the present invention, the line
The number recognition unit compares the output from each counter and
The count value by the write signal is the count by the write signal
An interrupt signal is output when the number exceeds the value.
Therefore, when an overrun is actually occurring , this interrupt
Signal can be output, and overrun
If it does not occur, this interrupt signal is never output
In addition, the printer engine is
Since it is driven and controlled by the output signal,
The output and the overrun error are closely related. others
Because, the accurate can detect the occurrence of an overrun error, therefore, it is possible to notify the quick printer user the occurrence of omissions can provide excellent page printer unprecedented.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a conventional example.

[Explanation of symbols]

 1 Drawing Unit 2, 3 Band Buffer 5 Character Loss Recognition Circuit 6 Writing Counter 7 Reading Counter 8 Line Number Recognition Unit

Claims (2)

(57) [Claims] 1. A drawing unit that draws print data received from a higher-level device into dot data and writes the dot data in a band buffer, a printer control unit that transmits the dot data from the band buffer to a printer engine, and a printer controller.
Based on the horizontal synchronization signal output from the controller
The dot data drawn in the buffer
In a page printer having a printer engine, the printer controller, a write counter for counting the number of writes to the band buffer of the dot data, as well as features and read counter for counting the number of output times of the horizontal synchronizing signal , of the read counter, an interrupt signal to the printer controller when the counted number count and by the read counter the read counter by comparing the count of the write counter has exceeded the count by said write counter A line number recognition unit for sending is also provided, and when the printer control unit receives an interrupt signal sent from the line number recognition unit, an error message provided in advance in the page printer is called and the error message is externally output. Error output machine A page printer having a function. 2. The page printer according to claim 1, wherein the error output function of the printer control unit is a display output function of displaying the error message on an operator panel equipped in the page printer.