JPH02235772A - Printing system - Google Patents

Abstract

PURPOSE:To effectively erase a memory area by a raster scanning and to prevent abnormal printing over plural pages due to runaway by setting partial area of a frame memory as a flag region, and rewriting the flag value of a flag region in synchronization with the raster scanning of the frame memory. CONSTITUTION:If an abnormal printing is judged, a processor 1 instructs to recover all data in a writable printing data area 10 for a raster scan controller 6, and once clears the content of the area 10. Printing data is again read from a code buffer 4 to complete printing dot image in a frame memory 5, flag values of first and second flag areas 12 are reset, and an abnormal recovery such as restart of a raster scanning is executed. That is, the flag is erased (updated) in synchronization with the raster scanning in the memory 5. Accordingly, whether the raster scanning is normally completed or not can be effectively determined by referring the flag value after the raster scanning.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a print control device such as a page printer, and particularly to a printing system using a raster operation method, in which abnormal printing can be reliably detected and countermeasures taken. Regarding the technology that can be used.

[Conventional technology]

An example of this type of technology described is Japanese Patent Application Laid-Open No. 162095/1983.

In the above publication, in a printing system using a raster operation method such as a laser beam printer, after reading a frame memory by raster scanning, erasing the same area and erasing the frame area are processed in parallel to improve efficiency. A technology has been disclosed to achieve this goal.

[Problem to be solved by the invention]

However, with the above technology, the scan timing and memory access may not be synchronized due to the influence of external noise during raster scanning, and this causes incomplete access to the memory. There is a possibility of termination. In this case, even if the access appears to be complete, erasing may remain incomplete, resulting in abnormal printing.

In addition, runaway may occur due to the mismatch between the scan timing and memory access, and there is a possibility that areas outside the area may be erased due to area overflow, resulting in abnormal printing over multiple pages.

In order to solve the above problem, it may be possible to refer to the value of the address counter used for raster scanning of the frame memory and use this value to determine whether the raster scan has completed normally. It was only possible to determine the presence or absence of a problem, and it was not possible to detect any abnormalities that occurred during the scanning process.

The present invention has been made in view of the above-mentioned problems, and its purpose is to ensure erasing of a memory area by raster scanning and to prevent abnormal printing over multiple pages due to runaway.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means to solve the problem]

A brief overview of typical inventions disclosed in this application is as follows.

That is, it is equipped with a frame memory that stores the print pattern as bit pattern data, sets a part of the memory as a flag area, and sets the flag value of the flag area in synchronization with the raster scan of the frame memory. It is something to be rewritten.

[Effect]

According to the above-described means, since the flag area set on the frame memory is handled in the same way as print data, the flag is erased (updated) in synchronization with the raster scan on the frame memory.

Therefore, by referring to the flag value after the raster scan, it is possible to reliably determine whether the raster scan has been completed normally.

Furthermore, depending on the setting position of the flag, it is possible to detect abnormalities in the middle of raster scanning in raster units or page units, which prevents printing abnormalities due to erase errors or printing defects over multiple pages due to runaway scanning. I can do it.

Embodiment C] FIG. 1 is a block diagram showing the system configuration of a printing apparatus that is an embodiment of the present invention, FIG. 2 is an explanatory diagram showing an outline of the address structure in the frame memory of this embodiment, and FIG. 3 FIG. 2 is a flow diagram showing a raster scan procedure in the frame memory of this embodiment.

As shown in FIG. 1, this system consists of a processor unit 1 and an external interface unit 3 connected via a bus 2.
, a code buffer 4, a frame memory 5, and a raster scan control section 6.

The processor section 1 performs overall control of this system, and the raster scan control section 6 performs control in raster scan processing.

An external interface section 3 connected to the processor section 1 through the bus 2 stores print data received from an external device 7 such as an office processor or a workstation system into a code buffer 4 through the bus 2 .

The processor section 1 reads the print data from the code buffer 4 through the bus 2 according to the system state, analyzes it, generates a corresponding bit image, and frames a frame for storing ON/OFF information corresponding to the print dots. Set in memory 5. Repeating this process,
The processor unit 1 completes a dot image in the print data area 10 on the frame memory 5 for one activation unit (for example, one page unit) of the printing device 8.

The structure of the data area on the frame memory 5 is as follows.
As shown in the figure, the word string from 0 to n+l and 0
It consists of raster rows up to m+1. In the figure, the final word column n+l and the final raster row m+l are set as flag areas (for convenience, they are referred to as a first flag area 11 and a second flag area 12).

When writing dot image data (drawing: step 31 in FIG. 3) to the print data area 10 of the frame memory 5, the processor unit l writes the first flag provided after each raster print data area 10. The flag values from the 0th raster to the mth raster in the area 11 are rewritten to (FFh) (h indicates hexadecimal notation), and the second flag area 12 of the m+l line corresponding to the next raster of the print data area 10 is The value of is also rewritten to (FFh) (step 32).In this embodiment, the flag value to be written is set to (FFh) for convenience, but of course it may be any other value.

By accessing the frame memory 5 as described above,
All flag values in the first and second flag areas 12 are (FFh).

After completing the above processing, the processor unit l starts raster scanning (step 33).Synchronizing with this raster scanning timing, the print data of the frame memory 5 is transferred to the bus for each raster from raster numbers 0 to m. 2, the print data is output to the printing device 8. At this time, in this embodiment, the processor section 1 writes (00h) in the read area when reading the print data in the frame memory 5. The print data area 10 is cleared.At the same time as writing (0 0 h) to the data area, when accessing the first flag area 11, the corresponding flag value is set to (0 0 h).
h).

The flag value (O O h) written above is read out by the processor section 1 at the completion of the raster scan (step 34), and its value is checked. At this time, the processor unit 1 reads out all the first flag areas 11 on the frame memory 5 and checks whether each flag value is (O O h) (step 35).

Subsequently, after the checking of the first flag area l1 is completed, the processor section 1 subsequently checks the second flag area l2 (step 36). At this time,
Since the aforementioned raster scan is performed between rows 0 to m, the value of the m+1 row on which raster scan has not been performed, that is, the second flag area l2, must remain (FFII). Steps 35 and 3 above
If no abnormality is detected as a result of the check in step 6, the processor unit 1 determines that the process has ended normally (step 38). On the other hand, if the check in step 35 is normal, but an abnormality is detected in the check in step 36, that is, if any flag value in the second flag area l2 is a value other than (FFh). In this case, the processor unit 1 determines that an abnormal termination has occurred.In the case of such an abnormal termination, a runaway has occurred due to the mismatch between the scan timing and memory access, and the data outside the area due to an area overflow has occurred. Since this is a case where erasing has occurred, if output to the printing device 8 is started as is, abnormal printing may occur over multiple pages.

On the other hand, if an abnormality is detected at the step 35 described above, the value of the second flag area 12 is further checked at step 37, and then the processor unit 1 determines that the abnormality has started 2.

In the case of abnormal termination 2 like this, print data area 1
This is a case where erasure (clearing) of 0 is incomplete, and there is a possibility that the print image in the next print data will be destroyed.

If abnormal printing 1 or 2 is determined above, Flosser B1 is under raster scan control! illS6
An instruction is given to recover all data in the print data area IO that can be written to the print data area 10.
Clear the contents once (write 0Oh))
, Abnormalities such as restarting the raster scan after reading the print data from the code buffer 4 again to complete the print dot image on the frame memory 5 and resetting the flag values in the first and second flag areas 12. Execute recovery processing.

In addition, in the above description of the embodiment, the first flag area 1
The case where all of the first and second flag areas 12 are checked has been described, but regarding the arrangement of the flag areas, the first and second flag areas 12 are checked. Third flag area 13 at the position of column n+1
It is also possible to provide a flag area and check this in the same way as the second flag area 12 described above. In short, it is sufficient if a part of the print data area 10 of the frame memory 5 can be set as a flag area.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above Examples and can be modified in various ways without departing from the gist thereof. Nor.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

That is, by setting a part of the area on the frame memory as a flag area and rewriting the flag value in the flag area in synchronization with the raster scan of the frame memory, the flag value can be set in synchronization with the raster scan of the frame memory. By erasing (updating) and referring to the flag value after the raster scan, it is possible to reliably determine whether the raster scan has been completed normally.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the system configuration of a printing apparatus that is an embodiment of the present invention. FIG. 2 is an explanatory diagram showing an outline of the address structure in the frame memory of this embodiment. FIG. 2 is a flow diagram showing a raster scan procedure in a frame memory. DESCRIPTION OF SYMBOLS 1... Processor section, 2... Bus, 3... External interface section, 4... Code buffer, 5...
Frame memory, 6... Raster scan control I, 7... External input device, 8... Printing device, 10...
Print data area, 11...first flag area, 1
2...Second flag area, 13...Third flag area, 31...Step, 32...Step, 3
3...step, 34...step, 35...step, 36...step, 37...step, 3
8...Step. Agent Patent Attorney Daiwa Tsutsui

Claims (1)

[Claims] 1. A frame memory is provided for storing the print pattern as bit pattern data, and a part of the area on the frame memory is set as a flag area, and the data is scanned in synchronization with the raster scan of the frame memory. A printing method characterized by rewriting a flag value in the flag area. 2. The flag area is set in the final raster of each page of the frame memory, and by referring to the flag, it is possible to determine whether or not the entire page is scanned. Printing method described. 3. The printing according to claim 1, wherein the flag area is set for each of all rasters in a page of the frame memory, and it is possible to determine whether or not scanning is performed for each unit scan during raster scanning. method. 4. The printing apparatus according to claim 1, wherein the flag area is set at a position following the last raster of the frame memory, so that it is possible to determine whether scanning beyond the corresponding page is performed during raster scanning. method.