JP2833161B2 - Page printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Overview] A page printer capable of executing full-page print control and band-buffer print control, wherein the band-buffer print control method is switched to the full-page print control method so that it can be used. At the time when the received print data is converted into an intermediate code and one page is stored, the printing mechanism is instructed to feed the paper, and the print pattern corresponding to the converted print data is stored in the bit map memory. The printing pattern is sequentially developed, and the printing pattern is read out by starting the raster scanning of the bit map memory in response to the sheet feeding completion signal of the printing mechanism, and the image formed on the image carrier is synchronized with the raster scanning. In a page printer that performs printing in page units, a detecting means for detecting that print data exceeding a predetermined amount has been received. Based on the result of the detection by the detection unit, the process of converting and storing the print data is stopped, and when a print pattern corresponding to the print data is developed for one page on the bitmap memory, The printing mechanism unit is provided with control means for instructing paper feeding.

[Industrial applications]

The present invention develops a print pattern on a bitmap memory, raster-scans the bitmap memory to read the print pattern, and forms an image on an image carrier in synchronization with the raster scan for printing. The present invention relates to a printer, and more particularly, to a page printer capable of executing full page print control and band buffer print control.

The page printer includes a control unit and a printing mechanism unit. Then, the control unit receives the print data from the host device, and sends a video signal obtained by raster-scanning the bitmap memory to the printing mechanism unit in synchronization with a synchronization signal sent from the printing mechanism unit. The printing mechanism modulates the light emitted by the light source with the video signal, scans the image carrier such as a photosensitive drum with the modulated light to form a latent image, and attaches toner to the latent image to develop the latent image. Then, printing is performed by a so-called electrophotographic method in which toner is transferred onto paper.

The page printer uses a full-page print control method in which, after a print pattern for one page is developed on a bitmap memory, printing is performed by raster-scanning the bitmap memory as described above. In order to save the capacity of the bitmap memory, one page of print data is converted into an intermediate code and stored, a print pattern is created from the converted print data, and a part of the one page print pattern is used. There is a method using a band buffer print control method in which the data is developed on a bitmap memory and raster scanning is performed on the bitmap memory to perform printing.

By the way, the full-page print control method and the band buffer print control method have advantages and disadvantages depending on the state of the print data, and it is desirable that each of them can be used by switching according to the state of the print data.

[Conventional technology]

A page printer that uses the full page print control method cannot be used as a page printer of the band buffer print control method. Similarly, a page printer using the band buffer print control method cannot be used as a page printer using the full page print control method.

[Problems to be solved by the invention]

When the printing mechanism for printing by the electrophotographic method starts printing for one page, even if the print pattern cannot be read from the bitmap memory in the middle, the printing cannot be interrupted and waited.

By the way, in a page printer using the full-page print control method, a print pattern for one page is developed on a bitmap memory, so that a print pattern for one page does not become unreadable during printing. However, the next page cannot be developed unless the print pattern for one page developed in the bitmap memory is read.
The printing speed is lower than the band buffer print control method. In order to increase the printing speed, the bitmap memory must be prepared for a plurality of pages, and there is a disadvantage that the memory cost increases and the page printer becomes expensive.

On the other hand, in the page printer of the band buffer print control system, only a part of the print pattern for one page is developed on the bit map memory, and the read pattern is read as the bit map memory is raster-scanned and the print pattern is read. Since the print pattern is sequentially written in the area of the bitmap memory in which raster printing is completed following the raster scanning, even if the bitmap memory capacity is only one page, the printing speed is faster than the full page print control method.

However, when the converted and stored print data is sequentially read, and a print pattern corresponding to the print data is read from a character generation circuit or the like and developed on a bitmap memory, if the number of characters to be printed on one page is large, However, there is a drawback in that the process of expanding the print pattern on the bitmap memory cannot catch up with the printing speed, and printing cannot be performed.

For this reason, when the number of characters to be printed is large, even if the capacity of the bitmap memory of the page printer using the band buffer print control method is increased so that a print pattern for one page can be developed, it is possible to prevent the printing from becoming impossible. , The page printer of the band buffer print control system,
Unless switching to the print control method is performed, there is a problem that it is not possible to use the page printer of the full page print control method only by increasing the capacity of the bit map memory.

The present invention has been made in view of the above-described problems, and when the number of characters to be printed on one page exceeds a predetermined value, the band buffer print control system can be switched to the full page print control system to perform printing. It is an object of the present invention to achieve a highly reliable page printer that can perform high-speed printing at a low price and does not make printing impossible.

[Means for solving the problem]

 FIG. 1 is a block diagram illustrating the principle of the present invention.

The page printer includes a control unit 1 and a printing mechanism unit 2. The control unit 4 of the control unit 1 converts print data received from a higher-level device into an intermediate code, and compares the print data with a print pattern developed in a bitmap memory. The compressed intermediate code is sequentially stored in the compressed data memory 5.

When one page of print data is stored in the compressed data memory 5, the control means 4 instructs the printing mechanism 2 to feed out the paper, and at the same time, reads out the converted print data stored in the compressed data memory 5. When a print pattern corresponding to the print data is generated, the bit map memory 6
A part of one page is sequentially developed at the top. Here, the storage capacity of the compressed data memory 5 may be extremely small as compared with the bitmap memory 6, so that there is almost no effect on the memory cost.

The printing mechanism unit 2 feeds out the sheet based on an instruction from the control unit 4, and when the sheet reaches a predetermined position, requests the start of raster scanning of the bitmap memory 6, and prints the print pattern read from the bitmap memory 6. Is formed on the image carrier, and this image is printed on paper.

The detection means 3 monitors the amount of print data received, and notifies the control means 4 when the amount of print data received by the control means 4 exceeds a predetermined amount.

When notified that the received print data exceeds the predetermined amount, the control means 4 stops the process of converting the received print data and storing the converted print data in the compressed data memory 5. , Write the data to the bitmap memory 6, and after receiving one page of print data, read the intermediate code stored in the compressed data memory 5, convert it to a print pattern, and write it to the bitmap memory 6. When the development of the print pattern for one page is completed, the print mechanism unit 2 is instructed to feed the paper.

[Action]

With the above configuration, the detecting unit 3 has a large amount of print data to be expanded in the bitmap memory 6, and the processing of expanding the print pattern from the print data stored in the compressed data memory 5 to the bitmap memory 6 is performed by printing. The control unit 4 detects that print data has been received beyond a predetermined amount at which printing cannot be performed without exceeding the printing speed of the mechanism unit 2 and becomes unprintable, and notifies the control unit 4. After developing the print pattern 9 for the minute, the print mechanism 2 is instructed to feed the paper.

Therefore, the page printer of the band buffer print control system can be used as a page printer of the full page print control system. In addition, the memory can be realized with the bit map memory 6 for one page and the compressed data memory 5 having a small capacity for a plurality of pages, and printing is not impossible due to the amount of print data. And high reliability.

〔Example〕

FIG. 2 is a block diagram of a circuit showing one embodiment of the present invention, FIG. 3 is a time chart for explaining the operation of FIG. 2, and FIG. 4 is a diagram for explaining sheet conveyance.

The page printer includes a control unit 1 and a printing mechanism unit 2. The control unit 1 receives print data from a host computer, sends a video signal in synchronization with a synchronization signal sent from the printing mechanism unit 2, and The unit 2 modulates light with the video signal and performs printing by a so-called electrophotographic system.

Print data is input from a host computer via a terminal A to a data input unit 9 for controlling an interface, is temporarily stored, is converted from a serial signal to a parallel signal, and is then sent to a data processing unit 10. The data processing unit 10 analyzes a command included in the print data and performs preprocessing for printing. Then, the data processing unit 10 first sends print data to the print data control unit 11 to start printing.

When the print data control unit 11 extracts a print code from the print data, the print data control unit 11 converts the print code into position information and an attribute for reading a character pattern from the character generation unit 12, and converts the extracted character code into a compressed data memory 5.
To be stored. When storing the print data for one page is completed, the print start control unit 13 is instructed to transmit a start signal via the data processing unit 10 at the end of the storage. And
At the same time, the print data control unit 11 reads out the intermediate code stored in the compressed data memory 5 and reads out the character pattern corresponding to the intermediate code from the character generation unit 12, and then develops a part of one page in the video map memory 6 sequentially. To start processing.

That is, the top and bottom margins, the line spacing, and the character spacing on the paper are calculated for each page of the paper, and each character pattern is sequentially written so as to be in the same state as printed on one page of the paper. Put in.

The print start control unit 13 sends a low-level start signal to the paper transport control unit 16 of the printing mechanism unit 2 as shown in the start of FIG. Start 16

The paper transport control unit 16 drives a motor (not shown) of a feed roller 23 of the hopper 22 shown in FIG. 4, and rotates the feed roller 23 to rotate the paper 24 set in the hopper 22.
And the sheet 24 is conveyed to the position of the standby roller 25. When a sensor (not shown) detects that the paper 24 has reached the position of the standby roller 25, the paper transport control unit 16 sends a low-level data to the print start control unit 13 as shown in the data output request in FIG. Sends an output request signal.

Since the print start control unit 13 is instructed by the data processing unit 10 to send a start signal, the reception of this data output request signal causes the video output unit 14 to send a video signal to the video output unit 14 as shown in the data output of FIG. The low-level data output signal to be instructed is transmitted, and the data output signal is also transmitted to the sheet conveyance control unit 16.

When receiving the data output signal, the paper transport control unit 16 raises the data output request signal to a high level.
The print start control unit 13 stops sending the start signal and the data output signal and sets the high level.

The video output unit 14 starts raster scanning sequentially from the upper end of the bitmap memory 6 based on the data output signal,
A video signal for one scan is sent to the raster print control unit 15 of the printing mechanism unit 2. The raster print control unit 15 controls the modulator 18 based on the video signal, modulates, for example, a laser beam transmitted from the light source 17, and causes the polygon mirror 19 to transmit the modulated laser beam.

The polygon mirror 19 is rotated by a motor (not shown),
The modulated laser beam is projected on the photosensitive drum 20 and the sensor 21. The raster print control unit 15 detects the scanning start timing of the laser beam for causing the polygon mirror 19 to scan the photosensitive drum 20 based on the output of the sensor 21, and sends a synchronization signal to the video output unit 14.

The video output unit 14 performs a raster scan on the bitmap memory 6 in synchronization with the synchronization signal, and sends a video signal for the next one scan to the raster print control unit 15. Since the photosensitive drum 20 is rotated by a motor (not shown), a latent image corresponding to a character pattern is sequentially formed on the surface of the photosensitive drum 20 every time the polygon mirror 19 performs one scan. Then, this latent image is developed by a developing device 26 using, for example, toner shown in FIG.

When notified of the transmission of the video signal by the data output signal, the paper transport controller 16 waits for the standby roller shown in FIG.
The photosensitive drum developed by the developing unit 26 in synchronization with the rotation speed of the photosensitive drum 20 by driving a motor (not shown) of 25
When the first line of the character pattern on 20 reaches the position of the transfer device 27, the paper 24 conveyed from the standby roller 25
The sheet 24 is transported so that the sheet 24 is sandwiched between the transfer device 27 and the sheet 24 and coincides with a predetermined printing start position of the sheet 24.

When the print data control unit 11 writes the character pattern up to the preset final area of the bitmap memory 6, the print data control unit 11 starts writing the character pattern again from the top area of the bit-up memory 6. That is, when an undeployed intermediate code is read from the compressed data memory 5 for an area from which a character pattern has already been read by raster scanning from the bit map memory 6, the corresponding character pattern is read from the character generator 12 and sequentially written. Put in.

When the video output unit 14 performs raster scanning to the preset final area of the bitmap memory 6, the video output unit 14 starts raster scanning again from the head area of the bitmap memory.

In this case, if the amount of print data from the host computer is small and there is a margin for developing the print pattern as compared with the raster scan of the bitmap memory, it is possible to develop the next page which is in advance to the address after the last area in advance. .

By repeating such operations, the character patterns for one page developed in the bitmap memory 6 are sequentially formed as latent images on the photosensitive drum 20 and then developed. One page of characters is transferred onto the paper 24, fixed by the fixing device 28, and discharged onto the stacker 29.

The data amount detection unit 7 outputs a predetermined amount from the terminal B, for example, 20
When 00 characters are set, the amount of print data input to the data input unit 9 is monitored, and when the set amount exceeds 2000 characters, a notification is sent to the print mode switching unit 8.

Upon receiving this notification, the print mode switching unit 8 instructs the print data control unit 11 to cancel the last area set in the bitmap memory 6 and enlarge the address to be sent to the bitmap memory 6; A character pattern for one page can be developed. And 20
For print data exceeding 00 characters, the corresponding character pattern is read from the character generator 12 and the 2000 bit data in the bit map memory 6 is read.
The character pattern is expanded from the area where the character is expanded to the last character pattern for one page.

The print data control unit 11 reads the already stored intermediate code for 1999 characters from the compressed data memory 5 and reads the corresponding character pattern from the character generation unit 12 according to the instruction of the printing system switching unit 8, and reads the corresponding character pattern from the bit map memory 6. Expand to Then, at this time, it instructs the print start control unit 13 via the data processing unit 10 to transmit a start signal.

Upon receiving the data output signal from the print activation control unit 13, the video output unit 14 having received the notification exceeding 2000 characters from the print mode switching unit 8 scans the area for one page of the bitmap memory 6 and performs raster scanning. A video signal is sent to the print control unit 15.

〔The invention's effect〕

As described above, the present invention can switch the page printer of the band buffer print control system to the page printer of the full page print control system. When it is received, it can be operated as a page printer of the full page print control system.

Therefore, high-speed printing is possible with a minimum memory capacity and printing is not prevented, so that a highly reliable printing apparatus can be provided.

[Brief description of the drawings]

 FIG. 1 is a block diagram for explaining the principle of the present invention, FIG. 2 is a block diagram of a circuit showing an embodiment of the present invention, FIG. 3 is a time chart for explaining the operation of FIG. 2, and FIG. FIG. 4 is a diagram illustrating paper conveyance. In the figure, 1 is a control unit, 2 is a printing mechanism unit, 3 is a detecting unit, 4 is a control unit, 5 is a compressed data memory, 6 is a bitmap memory, 7 is a data amount detecting unit, 8 is a printing method switching unit, 9 is a data input unit, 10 is a data processing unit, 11 is a print data control unit, 12 is a character generation unit, 13 is a print start control unit, 14 is a video output unit, 15 is a raster print control unit, and 16 is a paper transport control. Unit, 17 is a light source, 18 is a modulator, 19 is a polygon mirror, 20 is a photosensitive drum, 21 is a sensor, 22 is a hopper, 23 is a feed roller, 24 is a paper, 25 is a standby roller, 26 is a developing device, and 27 is a developing device. A transfer unit, 28 is a fixing unit, and 29 is a stacker.

Claims (1)

(57) [Claims] The print data received is converted into an intermediate code composed of character pattern reading position information and the like, and when one page has been stored, the printing mechanism is instructed to feed out the paper and converted into the intermediate code. The print pattern corresponding to the print data is sequentially developed on the dot map memory, and the print pattern is read out by starting the raster scanning of the bit map memory by the paper feeding completion signal of the printing mechanism unit, and the raster scanning is performed. In a page printer which prints an image formed on an image carrier synchronously on a page basis, print data to be developed into a print pattern of the one page of print data is received in excess of a predetermined amount. Detecting means for detecting that the print data has been converted into an intermediate code based on the detection result of the detecting means and storing the intermediate data. Te, a print pattern corresponding to the print data on the bit map memory 1
A page printer, further comprising control means for instructing the printing mechanism to feed out the sheet when the page has been developed.