JPH0220359A - printing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printing device that prints on both sides of a recording medium based on input printing information.

[Conventional technology]

2. Description of the Related Art Conventionally, an apparatus has been proposed that analyzes input print information on a page-by-page basis, develops print dot information corresponding to the analyzed print information in a page memory, and prints the information.

Also, in this type of printing apparatus, there is an increasing demand for double-sided printing on recording media, and the recording medium on which single-sided printing has been completed is reversely fed to print on both sides of the recording medium. In addition,
When printing on both sides, the information printed on one side and the information printed on the back side are
Since the output position of the printed image is relatively reversed, when printing on the back side, it is necessary to perform the development process on the page memory while reversing the least significant bit and the most significant bit of the printed dot data.

(Problem to be Solved by the Invention) However, since conventionally the printing dot data development process for the back page is entrusted to processing by software, it takes a considerable amount of time to develop the data based on address changes, and There was a serious problem in that there was a large difference between the development completion time and the development completion time during the back side printing process, resulting in a significant reduction in the back side printing throughput.

This invention was made in order to solve the above problems, and by using hardware to expand the print dot data into the page memory necessary for back side printing, the difference in front/back side printing throughput can be reduced. The purpose of the present invention is to provide a printing device which eliminates the need for double-sided printing and can greatly improve double-sided printing throughput with an inexpensive circuit configuration.

(Means for Solving the Problems) The printing device according to the present invention uses the least significant bit data of the bit image information developed as the backside printing information in the page memory as the most significant bit data during the double-sided printing process. The first gate means outputs the address to the image forming section while inverting the address, and the second gate means outputs the inverted least significant bit of the address output to the page memory.

[Effect]

In this invention, when double-sided printing processing is started and the recording medium on which front side printing has been completed is reversed by the conveyance unit and conveyed to the image forming unit, the first gate means is developed as back side print information in the page memory. The least significant bit data of the bit image information is output to the image forming section while being reversed upwards as the most significant bit data. At this time, the second gate means inverts and outputs the least significant bit of the address output to the page memory, and sequentially decrements the address.

(Embodiment) FIG. 1 is a block diagram illustrating the configuration of a printing apparatus showing an embodiment of the present invention. Reference numeral 1 denotes a control block that processes printing information input from an input interface IF. Reference numeral 2 denotes a printer block, which includes an image forming section 17, executes printing based on bit data developed in the scan buffer 6 of the controller block 1, and forms an image on a recording medium. Reference numeral 3 denotes a paper conveyance block, in which the recording medium that has been printed on one side is switched back (it is once conveyed a predetermined amount in the conveyance direction by a reversing roller (not shown), and then stopped, and then the reversing roller is reversed and the recording medium is moved opposite to the conveying direction again). The recording medium is conveyed so that the back side of the recording medium faces the image forming section 17.

4 is, for example, 68000 manufactured by Texas Instruments.
A CPU consisting of a ROM and a RAM (not shown), and a data bus 9. Page memory 5 connected to address bus 10. Controls access to scan buffer 6. Note that the page memory 5 has an input interface I/
For example, one page of dot images of print information input from F is stored.

7 is a second switch circuit, which has a gate (inversion gate) 13 that inverts the least significant bit of the address output to the address bus 10 when printing on the back side of double-sided printing, and is controlled by an input gate control signal 14. be done.

Reference numeral 8 denotes a first switch circuit, which is composed of gates 11 and 12, and the gate 11 develops print dot data output to the data bus 9 during normal printing into the scan buffer 6;
The gate 12 is actuated by a control signal 15 output when printing on the back side of double-sided printing, reverses the most significant bit and the least significant bit of the print dot data output to the data bus 9, and develops the reversed data in the scan buffer 6. 16 is an inverter gate that inverts the control signal 15; 18 is a paper transport section.

FIG. 2 is a cross-sectional view illustrating the configuration of a printing device to which the present invention is applied. Reference numeral 21 denotes a paper feed cassette serving as a paper feed section, and a pickup roller 22 drives a recording paper (recording medium).
21a into the machine.

A laser unit 23 scans the photosensitive drum 25 with a laser beam modulated based on the video signal output from the scan buffer 6.

A developing unit 24 develops the electrostatic latent image drawn on the photosensitive drum 25 into, for example, black.

A fixing device 26 fixes the developer transferred onto the recording paper 21a conveyed via the print guide 28 using heat and pressure. 27 is a switchback roller that can be driven in reverse.
During double-sided printing, the recording paper 21a is once conveyed by a predetermined amount, and when it passes through the paper feed selection switch 33, it is stopped once, and then it is driven in reverse rotation to move in the direction set by the paper feed selection switch 33, that is, the paper refeed guide 30. feed the paper by pulling it in the direction.

31 is a paper ejecting guide, and the recording paper 21a after the printing process has been completed.
Functions as a paper path for ejecting and transporting paper. A paper discharge roller 32 conveys and discharges the recording paper 21a along the paper discharge guide 31.

In addition, during normal one-sided printing, press the paper path selection switch 3.
4 is set upward to the right, and the recording paper 21a conveyed via the print guide 28 is conveyed in the direction of the paper discharge roller 32. In addition, when printing on the front surface of double-sided printing, the paper path selection switch 34 is set horizontally, and the recording paper 21a conveyed via the printing guide 28 is first conveyed in the direction of the switchback roller 27, and then the paper path selection switch 34 is set horizontally. 34 to recording paper 21
When the trailing edge of the recording paper 21a passes, the switchback roller 27 is stopped, the conveyance of the recording paper 21a is stopped, and the paper path selection switch 34 is installed on the upper right side. Thereafter, the switchback roller 27 rotates in the reverse direction to draw and feed the recording paper 21a toward the paper refeed guide 30.

Furthermore, when printing on the back side of double-sided printing, the paper bus selection switch 34 is set horizontally, and the recording paper 21a that has been printed on the front side is fed again from the refeeding port provided in the refeeding guide 30, and the paper bus selection switch 34 is set horizontally. 28. Paper ejection roller 32. Paper ejection guide 2
The recording paper 21a conveyed through the paper 9 is conveyed to be ejected.

Next, the operation shown in FIG. 1 will be explained.

During normal printing, the gate control signal 14. control signal 15
are both set to L level, and the gate 11 of the first switch circuit 8
The gate 12 is opened and the gate 12 is separated.

At this time, the inverting gate 13 of the second switch circuit 7 is disabled, and the contents of the address bus 10 are output to the page memory 5 as they are. Then, print bit data developed in the scan buffer 6 (normally developed from low-order bits to high-order bits) is output to the printer block 2 according to the incremented address. Then, from the image forming section 17 to the recording medium 2
A printed image is formed on 1a.

On the other hand, when printing on the back side of double-sided printing, the control signal 15 is set to H.
level, and the gate 12 of the first switch circuit 8 is enabled and the gate 11 is disabled.

The CPU 4 outputs the lowest address for one page as the readout address of the back print information developed in the page memory 5. In addition, CPU4 is especially 68000
In the case of a series processor, addresses are added when longword transfer is performed during data transfer, so addresses are automatically added. Therefore, the least significant bit of the address is inverted by the inverting gate 13 of the second switch circuit 7. This pseudo-decrements the address. Then, the print bit data read out sequentially according to the decremented address is sent to the gate 1.
2, the data is developed in the scan buffer 6 while being inverted. As a result, the image forming section 17 prints the back side printing bit data, which becomes a valid image at the end of printing, in reverse order on the inverted recording medium 21a.

FIGS. 3(a) and 3(b) are schematic diagrams illustrating an example of double-sided printing output according to the present invention, and the same parts as in FIG. 1 are given the same reference numerals.

In these figures, 41 is a surface print image, for example "
This corresponds to an image obtained by outputting print bit data from low to high in the conveyance direction (arrow A) of the recording medium 21a. 42 is the image printed on the back side,
For example, it indicates "O" and corresponds to an image obtained by outputting print bit data from high to low in the conveyance direction (arrow A) of the recording medium 21a. Note that the front surface print image 41 is indicated by a broken line.

As can be seen from these figures, during front side printing, a front side print image 41 is obtained by outputting print bit data to the recording medium 21a in accordance with sequentially incremented addresses. Then, when preparations for printing on the back side of the inverted recording medium 21a are completed, the print bit data developed in the page memory 5 is printed while being inverted, contrary to the case of printing on the front side, thereby obtaining a back side print image 42.

At this time, the inverted print bit data is outputted from the gate 12 at a speed equivalent to the normal printing processing speed and sequentially expanded to the scan buffer 6 without performing inverted output by software processing as in the conventional art. Therefore, a decrease in printing processing speed during back side printing is prevented, and a decrease in printing throughput is prevented.

FIG. 4 is a flowchart showing an example of a double-sided printing process procedure according to the present invention. Note that (1) to (11) indicate each step.

First, the CPU 4 determines whether the print designation is one-sided printing (1), and if YES, executes normal printing processing (2).
, ends the process.

On the other hand, if the judgment in step (1) is NO, it is necessary to judge whether or not it is printed on the front side (3), and if the judgment is No, step (
Proceed to step 8). If YES, set the flapper that controls the conveyance direction of the recording medium 21a. 4) and wait for paper feed command input.
Print data development is the same as normal printing) (6).

Next, a switchback process is performed on the recording medium 21a on which the front side printing has been completed (7) to prepare for the back side printing process.

Next, the system waits for a paper feed command for backside printing to be input (8), and when the paper feed command is input, the recording medium 21a
At the same time, the readout address of the print information developed in the page memory 5 is output (9). Next, the gate 12 inversely develops the print bit data outputted to the data bus 9 into the scan buffer 6 with the highest bit as the least significant bit (10). Next, the image forming section 1
7 starts printing based on the print bit data for the back surface reversely developed from the scan buffer 6 (11), and when the back surface printing image is completed, the recording medium 21a is ejected and the process ends.

In the above embodiment, the print bit data developed in the page memory 5 is reversed when it is developed into the scan buffer 6, but it may be reversed when the page memory 5 is read. Furthermore, in the above embodiment, a case has been described in which reversed print bit data is expanded to the printer block 2 via the scan buffer 6, etc.
The present invention can also be applied to storage elements such as FO (first-in-first-out) memories.

(Effects of the Invention) As explained above, the present invention reverses the least significant bit data of the bit image information developed as back side printing information in the page memory as the most significant bit data during double-sided printing processing toward the upper side. However, since the first gate means outputs the output to the image forming section and the second gate means inverts and outputs the least significant bit of the address output to the page memory, the printing bits in the back side printing of double-sided printing are It has the excellent effect of greatly speeding up the development process and greatly improving double-sided printing speed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating the configuration of a printing device according to an embodiment of the present invention, FIG. 2 is a sectional view illustrating the configuration of a printing device to which this invention is applied, and FIGS. ) is a schematic diagram illustrating an example of double-sided printing output according to the present invention, and FIG. 4 is a flow chart showing an example of the double-sided printing processing procedure according to the present invention. In the figure, 1 is a control block, 2 is a printer block, 3 is a paper transport block, and 4 is a CPU. 5 is a page memory, 6 is a scan buffer, 7 is a second switch circuit, 8 is a first switch circuit, 9 is a data bus,
10 is an address bus, 11 and 12 are gates, 13 is an inversion gate, 17 is an image forming section, and 18 is a paper transport section. Figure 1a

Claims (1)

[Claims] A page memory that expands and stores bit image information corresponding to input image information, an image forming unit that forms an image on a recording medium based on the bit image information expanded in this page memory, and an image that is formed by this image forming unit. In the printing apparatus, the least significant bit of the bit image information developed as back side print information in the page memory during double-sided printing processing is used. a first gate means for outputting the data to the image forming section while inverting the data toward the upper part as the most significant bit data; and a second gate for inverting and outputting the least significant bit of the address to be output to the page memory. A printing device characterized by comprising means.