JPS6036672B2 - high speed fax machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a facsimile band compression method using a multi-point simultaneous printing method, particularly a thermal multi-point simultaneous printing method.

(Prior Art) The printing section of a conventional facsimile using thermal printing uses a thermal head in which a large number of heat-generating resistors are arranged in a straight line.A current is passed through each heat-generating resistor, and the generated Joule heat is transferred to the head. The information is transmitted to thermal recording paper that is placed in close contact with the
I'm looking for a way to make it color.

In principle, thermal coloring takes a relatively long time to print (
(approximately 5 to 8 ms) Therefore, a multi-point simultaneous printing method that prints multiple points (dots) at the same time is being explored. FIG. 1 shows an example of a facsimile receiver using a multi-point simultaneous printing method. The facsimile signal 1 transmitted serially in time is stored in a serial input/parallel output shift register 2 by a clock 3 synchronized with the sampling of the facsimile signal 1.

When the length (number of bits) of the facsimile signal 1 becomes equal to the length of the shift register 2, a clock pulse 4 is issued and the contents of the shift register 2 are transferred to the parallel input parallel output shift register 5. Next, shift register 2
The subsequent facsimile signals 1 are stored in sequence. Switches 61a, 61b, etc. are opened and closed according to the image information transferred to the shift register 5 (switches corresponding to dots to be printed are closed, and other switches are closed). The thermal head has a large number of heat generating resistive elements 71a, 7-b arranged in a straight line, one terminal of which is connected to a diode 8-a, 8-b.
etc., and are connected to the switches 6-a, 6-1b, etc. through a diode matrix formed by wires 91a, 91b, etc. The other terminals of the switches 6-a, 6-b, etc. are grounded. The other terminals of the heating resistive elements 71a, 7b, etc. are connected to the same number as the switches 61a, 6-b, etc., and are divided into blocks. Each block is connected to a switch 10-a, 10-b, etc., and the other terminal of the switch 10-a, 10-b, . . . is connected to the positive terminal of a power source 12 through a switch 11. The negative pole of the power supply 12 is grounded. Switch 10-a, 1
0-b... are sequentially closed one by one by the selector circuit 13. Here, when the image information is transferred to the shift register 5, the selector circuit 13 operates so that the switch 10-a at the left end in FIG. The switch 11 is set for a certain period of time (printing time 5 to 8 m) by the printing time control pulse 14.
s) closed.

At this time, power supply 12 → switch 11 → switch 10-a →
Current flows as follows: heating resistor element 7 → diode 8 → switch 6 (closed) → earth → ground of power supply 12 This corresponds to the case where switch 6 is closed in the leftmost block in Figure 1. The heating resistor element generates heat, and image information is printed. When the next facsimile signal is accumulated in the shift register 2, the same operation as above is performed, but the switches 1 and 10-b are closed and the others are opened, so in FIG. The th block performs the printing operation. Thereafter, printing is performed sequentially up to the rightmost block, completing one main scan. (Problems to be Solved by the Invention) When attempting to shorten the transmission time of calligraphy and drawings using the conventional thermal multi-point simultaneous printing method facsimile as described above,
The transmitter side determines the presence or absence of image information to be printed for each block, and only transmits a code (for example, "0" lbit) indicating this for blocks that do not have image information to be printed (referred to as skip blocks). However, if a block has image information (not a skip block), all the data of that block is transmitted, and in the case of a skip block, the selector circuit 13 (Fig. 1) advances one step forward. A castle compression method was being explored.

Generally, the resolution in the main scanning direction of a facsimile using a telephone line is 4 to 60 degrees, and the transmission speed is 2000 to 60 degrees.
00 bps (bit/sec), so for example, if the resolution is 5.3 ot/side, the transmission speed is 2400 bps, and the print time is 6.8 hs, then when the print time and transmission time are equal, the waiting time will be the same for both. becomes zero, so 1
The number of bits n in the block is the older sister.

Since Xn=6.6 (mS), n〒16 (dots).

In addition, when n = 16, the length of one block on the manuscript is x 16
There will be 3 ribs.

According to experiments with English and Japanese text, which are often used in facsimile transmission, when the above band compression is performed, if the flock length is less than 2 skins, the blocks are too short and there are many skip codes, resulting in 3 ribs. If the length is longer, there will be more parts that are not image information included in one block (that is, white signals), so the minimum number of transmission bits for one main scan is 1.
Since it is known that one block has two or three skins, the above example can be said to be optimal if a transmission rate of 2400 bps is used.

Furthermore, consider trying to shorten the transmission time of calligraphy and drawings by increasing the transmission speed. Recently, it has been put into practical use4
Applying the case where an 800 bps modem is used, n=32 dots, and the length of one block is on the 6 side.

In this case, as mentioned above, the length of one block increases and the amount of non-image information contained in one block increases, reducing the efficiency of band compression, and even though the transmission speed doubles, the transmission time is halved. The disadvantage is that it does not. The present invention has been made to eliminate the above-mentioned drawbacks and will be explained below with reference to the drawings.

(Means for Solving the Problems) The present invention is a digital facsimile apparatus in which the transmitting side and the receiving side respectively perform digital scanning in both main scanning and sub-scanning, and in which one main scanning line is divided into a large number of blocks, and each block determine the existence of image information about
Send only a code indicating that no image information exists,
A block that has image information transmits all the image information of that block, and after receiving two or more blocks that have image information, the receiver side simultaneously energizes the heating resistor elements of the thermal head for the blocks to perform thermal printing. In high-speed facsimile machines that use For one block length selected in advance, that is, 2 to 3 willows, the time to transmit the length of one block and the time t2 required for one energization of the thermal printing on the receiver side are t2 = This is a high-speed facsimile machine characterized in that it prints n blocks at the same time.

(Operations and Embodiments) FIG. 2 is an explanatory diagram of a printing section of a thermal multi-point simultaneous printing facsimile using a two-block simultaneous printing method, which is an embodiment of the present invention.

The facsimile signal 1 is input to serial input/parallel output shift registers 15 and 16, and their outputs are input to parallel input/output shift registers 7 and 18, respectively.

(Shift registers 5, 16, 17, and 18 have the same number of bits) The outputs of shift registers 17 and 18 are each switched to switch 1.
Controls the opening and closing of 91a, 191b, . . . and 20-a, 201b, . A large number of heat generating resistive elements 71a, 7-b, . a, 10-b,
..., and the other terminals of the switches 101a, 101b, ... are connected to the positive electrode of the power source 12 through the switch 11. The negative terminal of the power supply 12 and one terminal of the switches 191a, 191b, etc. 20-a, 201b, etc. are grounded. The distribution circuit 21 includes switches 19-a, 1
91b, etc., 20-a, 201b, etc. and the heating resistance elements 71a, 7-b, etc. are connected, and the switch group 19 and the block with the heating resistance element (for example, the m-th block) and switch group 20 and another block (for example n
connection designation signal 22 for each block (where m≠n)
It is a gate connected by.

Further, the distribution control circuit 23 generates a signal for closing the switches 10-m and 10-n corresponding to the blocks to be printed (m and n in the above example) and a connection designation signal 22. Next, the operation will be explained with reference to FIG.

When the facsimile signal 1 which is time-series and band-compressed is input, the control circuit 24 determines whether it is a skip block or an apricot skip block. If the block is not to be skipped, the clock 25 of the shift register 15 is output, and the image information for one block in the facsimile signal 1 is stored in the shift register 15. Next, when the Anzu skip block appears, shift register 1
6 clocks 26 are output, and image information for 17 locks in the facsimile signal 1 is stored in the shift register 6. When the image information is stored in shift registers 15 and 16, clock pulse 2 of shift registers 17 and 18
7 is issued, the contents of shift register 15 are transferred to shift register 7, and 16 is transferred to shift register 18. The control circuit 24 receiving the facsimile signal 1 notifies the distribution control circuit 23 of which block the image information in the shift registers 17 and 18 corresponds to, and controls the switch 10 and the distribution circuit 21, thereby controlling the switch 10 and the distribution circuit 21. Image information is connected to blocks of heating resistive elements corresponding to each block.

Then, the switch 11 is closed for the printing time, and the power supply 1
2 flows through the heating resistor element located at the position where color should be generated, causing the thermal recording paper to develop color. Thereafter, image information in the facsimile signal is sequentially extracted and printed two blocks at a time. In this case, if the length of one block is 1&it, the resolution is 5
．． In the case of 3 phantom/skin, the length of 1 block on the manuscript is 3
mm, the compression efficiency is maximum, and 4800bp
s transmission, the time required to transmit two blocks of image information is 1/4800 x 16 x 2 = 6.6 (m
s), which is equal to the printing time. That is, the relationship holds that when the transmission speed doubles, the transmission time is halved. Furthermore, when using a transmission speed of 9600 bps,
It is clear that it is sufficient to print four blocks at the same time. That is, the transmission speed is Pbps, and the resolution is Qdot/
If the printing time is Tsec, the length of one block is L side, and the number of blocks printed at the same time is n, then L x Q: 1
Number of dots (number of bits) of image signal of block LXQXK = Transmission time of image signal of 1 block (Sec
) LXQX Takashi Xn = Misaki no Bu.

time to transmit the image signal
(sec), and L×Q×1/P×n is the printing time T
If it is made equal to , the transmission time and printing time will be equal, and the waiting time will be zero in both cases, resulting in good efficiency. Next, the configuration of the distribution circuit 21 of the embodiment shown in FIG. 2 will be considered.

When the distribution circuit 21 is operated as described above, its basic circuit becomes as shown in FIG. Switch 28-1 is a change-over switch having contacts as many as blocks for one entire main scan, and its arm 29 is connected to switch 19 (FIG. 2). Switch 30- has the same number of contacts and its arm 31 is connected to switch 20 (FIG. 2). The switches 28-1 and 30-- are connected to the heating resistance elements 32-1, 33-1, and 33-1 at the beginning of each block.
34-. ...is selected.

The switches 28-1, 28-2, . . . , 28-m operate in conjunction with each other, and are connected to one of the blocks by the connection designation signal 22 (FIG. 2). Switch 30- is similar, but is not followed in the same block as switch 28-. As is clear from FIG. 3, such a switching circuit requires a large number of gate ICs, making the device large;
It is possible if you convert it into a melon.

Therefore, if a diode matrix is used for this switching, it will not become complicated.

Therefore, if the thermal head for one main scan is divided into two parts and each part has a diode matrix configuration, printing can be performed at two locations simultaneously. The configuration at that time is shown in FIG. Lock 7 in FIG. 4, which is indicated by the same number as in FIG. 2, operates in the same way as in FIG. 2, so a description thereof will be omitted.

The part surrounded by the dashed line is the diode matrix,
The diode matrix 35 is constituted by a group of heating resistive elements in the left half of the thermal head, and the diode matrix 36 is constituted by a group of heating resistive elements in the right half. In the case of this embodiment, the following is performed on the transmitting side for facsimile signal 1. Determine whether the skip block is on the left half or the right half of the document, make two skip blocks bare, and in each bear there is one on the left half and one on the right half. Transmit to include. FIG. 5 shows the correspondence between an example of a document and a facsimile signal.

When main scanning is performed horizontally at the position of the arrow 38 on the original 37, an image signal as shown in a waveform 39 is obtained. If this is divided into blocks and there is image information, the level is high.
If the areas where there is no signal are displayed as 0 at a low level, the result will be as shown in waveform 40. In this example, the main scan is divided into 26 blocks, and if the blocks are numbered from the left as ■, ■, ..., ■, the blocks containing image information are ■, ■, ■, ■, ■.
,...,■. Here, select the blocks from ■ to ■.
The images are divided into groups into the left half of the screen up to ■ and the right half of the screen up to ■, and the facsimile signals 41 are generated by extracting one block at a time from the left of the blocks containing image information in each group. Then, it is ■, ■, ■, ■...■, ■. The image signals of the blocks are lined up, and if two blocks are output from the beginning, image information corresponding to the matrices 35 and 36 in FIG. 4 will be obtained. In this way, two blocks can be printed simultaneously without using a complicated gate circuit.

Furthermore, the number of matrices can be increased by setting the number of groups to two or more.

You can also print the number of matrices at the same time. It is clear that the number of matrices does not have to be the same, and it is also conceivable to set the number of matrices to 4 to 6 and print two or three of them at the same time. Although not shown in the "Facsimile 1" signal 41 of FIG. 5, it is actually necessary to indicate to the receiver which block of image information the image information belongs to.

(Effects of the Invention) As described above, by using the apparatus of the present invention, it is possible to produce a thermal facsimile that has a high band compression ratio, can equalize the transmission time and printing time, and can perform high-speed transmission.

Brief Description of the Drawings Fig. 1 is a system diagram of the printing section of a conventional facsimile receiver, Figs. 2 to 4 are system diagrams showing an embodiment of the present invention, and Fig. 5 is a facsimile signal waveform in the present invention. It is an explanatory diagram.

1...Facsimile signal, 2...Shift register, 3...Clock, 4...Clock pulse, 5...
...Shift register, 6-a, 6-b...Switch, 7-
a, 7-b...Heating resistance element, 81a, 81b
...Diode, 9-a, 91b...Wiring, 101a,
10b...Switch, 11...Switch, 12...
...Power supply, 13...Selector circuit, 14.・・・
...Printing time control pulse, 15-18...Shift register, 191a, 19-b, 20-a, 201b...Switch, 21... distribution circuit,
22...Connection designation signal, 23...Distribution control circuit.

Tsutomu illustration 2 illustrations Figure 3 *Figure 4 *Figure 5

Claims (1)

[Claims] 1. A digital facsimile device in which the transmitter side and the receiver side perform digital scanning in both main scanning and sub-scanning, respectively, which divides one main scanning line into a large number of blocks, and determines the presence of image information for each block,
Blocks that do not have image information transmit only a code indicating that no image information exists, blocks that do have image information transmit all of the image information for that block, and the receiver side sends two blocks that have image information. In a high-speed facsimile machine that performs thermal printing by simultaneously energizing the heating resistor of the thermal head for the block after receiving the above, the number of bits of the code indicating that there is no image information in one main scanning line and the image information are One pre-selected block length, i.e. 2 to 3, that minimizes the sum of all bits of information in the block, if any.
mm, print n blocks at the same time such that the time t_1 for transmitting the length of one block and the time t_2 required for one energization of the thermal printing on the receiver side satisfy t_2≒t_1n. A high-speed facsimile machine characterized by: