JPH10200670A - Image input / output interface - Google Patents

Abstract

(57) [Summary] Since the data transfer rates of the image input means and the image output means are different, it is difficult to synchronize the image data and it is difficult to copy immediately. Further, since it is difficult to print the same image data side by side, the image cannot be enlarged. A copying apparatus includes an image input unit, an image output unit, and an interface connecting the two.
A plurality of memories and a drive signal oscillation circuit 4 are provided in the interface portion. In accordance with the synchronization signal of the image output means 3, the drive signal oscillation circuit 4 causes a set of memories to store the image data from the image input means in synchronization with the printing area. The other memory outputs the stored image data to the image output means. The memory is changed according to the synchronization signal, and the image data is transferred.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image input / output interface.

[0002]

2. Description of the Related Art Conventionally, when an image input device and an image output device are separate, a method of using a computer as a host control device has been generally used. First, a conventional example in which an image input means and an image output means are separate and a general-purpose interface is connected between them will be described with reference to FIG.

The general-purpose interface generally indicates a serial interface (RS232C or the like) or a parallel interface (SASI, SCSI interface, or the like) for connecting a computer to a scanner, a computer to a printer, a computer to an external storage device, and the like. Is an interface provided by each computer maker and peripheral device maker.

Conventionally, as shown in FIG.
And the image output means 3 are separate units, and in a copying system connected by a general-purpose interface, the central control unit 2 is required. First, the computer 2, which is the central control device,
General-purpose bidirectional parallel interface, especially SCSI
The image scanner 1 serving as image input means is controlled through an interface to store image data in a memory inside the computer. Next, the computer 2 outputs image data to the printer 3 serving as image output means through a general-purpose printer interface. Now, when the printer is a page printer, it is stored in an image memory inside the printer. The printer processes and outputs an image according to the sent image data.

According to the conventional method, image data is transferred a plurality of times from the scanner to the frame memory and from the frame memory to the printer. Therefore, data transfer at a speed synchronized with the scanner and data transfer at a speed synchronized with the printer are performed. There is an advantage that the transfer can be performed and there is no need to synchronize the scanner and the printer. However, since the image data is stored in a memory or the like during the transfer from the image input unit to the image output unit, reading and writing time is required in the memory and the like, and the time required for copying is long.

Japanese Patent Laid-Open Publication No. Hei 7-156460 discloses a printer in which data read by a scanner is directly printed out by a printer without passing through a host device, thereby speeding up the printout and improving operability and versatility. There is a provision of equipment.

However, in this configuration, since the frame memory is used, the image data from the scanner is temporarily stored in the frame memory, and the image data is output from the frame memory to the printer, and it takes time from reading to printing. .

[0008]

As described above, the method of reading an image and printing it later requires a memory for holding the image data, which is expensive. Further, since the image data is once stored in the frame memory, it is difficult to read and print the image at the same time.

When printing is performed without using the frame memory, the printer synchronization signal corresponding to the printing speed of the printer and the drive signal corresponding to the reading speed of the scanner are moving at different timings, so that copying is performed immediately. It was difficult.

Simply storing image data from a scanner in a small amount of memory and outputting the image data from the memory in accordance with the printing speed of a printer is almost the same as in a FIFO memory.

However, when outputting low-resolution image data with a high-resolution printer or when enlarging and outputting an image, it is necessary to partially print one image data a plurality of times.

[0012]

SUMMARY OF THE INVENTION According to the present invention, there is provided a copying apparatus having image input means for reading an image into image information, image output means for printing the image information, and a general-purpose interface for connecting the two. In accordance with synchronization signals such as a horizontal synchronization signal, a vertical synchronization signal, and a pixel synchronization signal, a printing area in an image output is detected.
At least one between the interface and the image output means
A plurality of memories of lines or more are provided, and switching means is provided for switching one memory to use for inputting image data from the image input means and the other memory to use for outputting to the image output means.

Further, a drive signal oscillating circuit for generating a drive signal for image input at a predetermined timing is provided, and a counter for setting an amount of data to be input or output at a time is provided. By providing a drive signal generation circuit capable of stopping the operation, image data can be input and output at high speed.

Thus, while one memory is being input, the other memory can output a plurality of times, not just once, and the image can be easily enlarged.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The image input means mainly means an image scanner, and means an image input device such as a digital still camera. The image output means mainly refers to a page printer such as a laser printer, but refers to a serial printer such as an ink jet printer or a thermal transfer printer, and other image output devices. Hereinafter, the image input means is described as a scanner, and the image output means is described as a printer.

A feature of the present invention is that a plurality of sets of memories capable of storing a plurality of lines of image data are provided between a printer and a scanner without using a frame memory, and the printer side and the scanner side are driven by different clocks. One memory stores image data from the scanner, and the other memory sends image data to the printer and prints an image, by synchronizing the scanner and the printer with a printer synchronization signal.

An embodiment of the present invention is shown in FIG. 1 and will be described below. The details will be described below in accordance with the copying procedure. In addition,
The figure illustrates a state in which image data at the time of copying is transferred from the scanner to the printer, and cannot sufficiently explain a method of initial setting or control of the scanner or the printer.

A copying circuit is provided between the interface between the image input device 1 and the image output device 3. In the copy circuit,
Copy control means for controlling the image input means and the image output means must be provided, and the image input means and the image output means must first be initialized. After turning on the power of the image input device 1 and the image output device 3, a color, an image size, a magnification, and the like must be selected and set in order to obtain a desired copy image. This setting method is performed in the same procedure as the conventional setting from a computer.
In general, the scanner 1 is set with white balance adjustment, reading size, resolution, color, number of gradations, and the like. Colors, media, and the like are set for the printer 3. To perform the setting, it is desirable to use a setting circuit using a custom IC or the like provided in the copy control means, but a general-purpose computer may be used.

Next, a copy start command is issued by using a copy button or the like, the printer is activated so as to perform printing, and the scanner generates a data request signal.

The driving signal oscillating means, which is a feature of the present invention, comprises:
It is located together with the copy control means inside the copy circuit.

For connection between the scanner and the copying circuit, a general-purpose interface is preferable, and a bidirectional parallel interface, preferably a SCSI interface, etc. is preferable. In addition, the connection between the copying circuit and the printer requires wiring of a synchronization signal from the printer in addition to the bidirectional parallel interface. The following is the SCSI interface standard (A
NSI X3.131-1994, Reference: Seiichi Sugaya, "SCI-2 Detailed Description Latest SCSI Standards and Command References, CQ Publishing Company", bidirectional parallel provided by each imaging equipment manufacturer and each interface manufacturer May be different from interface name. Since there is a signal line that performs the same operation, it is necessary to replace the signal line and consider it.

FIG. 1 shows two line memories 5a and 5b.
FIG. 3 is an explanatory diagram of an embodiment of the present invention having a switching unit 10 and a driving signal oscillating unit 4. Mainly, when a laser printer starts printing, it cannot wait for image data to print, so the printer must obtain enough image data from a scanner to print. Now, by providing a line memory between the scanner and the printer, it is possible to input image data from the line memory at a pixel clock (period necessary for printing one pixel) required by the printer. However, one line memory has to switch between a mode for storing image data from a scanner and a mode for sending image data to a printer, and a printer for high-speed printing (particularly a laser printer)
In this case, the transfer of image data could not keep up with the printing speed of the printer, and the two modes could not be switched with a margin.

Therefore, by using the two line memories 5a and 5b and the switching means 10 as in the present invention, one of the line memories is set to the mode for storing the image data 6 from the scanner, and the other line memory is set to the printer. By executing the mode for transmitting the image data 7, the input and output of the image data can be performed simultaneously. For example, when a certain horizontal synchronization signal HSYNC is input, the memory 5
a inputs and stores image data from a scanner, and the memory 5b outputs image data to a printer. Next, when the horizontal synchronizing signal HSYNC is input again, the memory 5a and the memory 5b alternately input and output data by the switching means.

The switching means uses the synchronization signal of the printer 3 to switch between the two memories. The start of printing and the start of reading can be determined by using a signal indicating the end of the printing area, such as a horizontal synchronization signal or a vertical synchronization signal. The printer starts printing according to the synchronization signal, finishes printing at a predetermined time, and proceeds to the next line after waiting for the synchronization signal. The scanner starts reading when a synchronization signal comes, and must read predetermined image data before the next synchronization signal comes.

As shown in FIG. 3, the pixel clock of the printer and the reading speed of the scanner need not always be the same. The pixel clock of the printer depends on the printing speed of the printer. On the other hand, the reading speed of the scanner need only be able to read predetermined image data in the time between the synchronizing signal and the next synchronizing signal, and therefore does not need to be synchronized with the pixel clock of the printer.

Therefore, by providing a drive signal oscillation circuit that determines the speed at which image data is read from the scanner, image data can be read at a speed different from the pixel clock. The drive signal Rclk generated from the drive signal generation circuit is a signal pulse necessary for a predetermined amount of image data 6 read from the scanner, and is generated between a synchronization signal sent from the printer and the next synchronization signal. For example, the horizontal synchronizing signal HSYNC of the printer becomes low (Lo) every 500 ns.
w), and when the low state indicating the print area returns to the high (Hi) state for 400 ns and then returns to the high (Hi) state, the pixel clock Wclk sent to the printer has a cycle of 0.2 ns for one dot, assuming 2000 dots per line. On the other hand, since reading can be performed in 500 ns, one dot is 0.25 ns.
The following is good. That is, it can be realized by inputting a read signal Rclk to the scanner at 4 MHz or more. Specifically, a data response signal ACK is received in response to a data request signal REQ from the scanner, which is a reading signal.
At a predetermined timing, that is, every 0.25 ns in the case described above. Incidentally, the pixel synchronization signal of the printer is 5 MHz in the case described above.

As described above, the reading speed is appropriately set so that reading is started in accordance with the synchronization signal for each line, and the next synchronization signal comes just after the reading is completed.
However, when one line of image data has been written to the memory, the operation is stopped until the next synchronization signal comes.

The smaller the capacity of the memory is, the better, preferably, only two memories for one line. By using a memory having a capacity of one line or more, or using a plurality of memories, there is ample time for reading and writing image data, and the invention can be applied to image processing and the like. Conversely, a memory of one line or less can be used, but at that time, a plurality of image synchronization positions must be provided. For example, when two half-line memories are provided, a synchronization signal must be provided at the center of the printed image in the main scanning direction, and it is necessary to newly provide a means for detecting a pixel synchronization signal of the printer.

The capacity of image data to be handled at one time is as follows. Since the amount of image data to be read at one time is determined, another embodiment showing the feature of the present invention is based on a synchronization signal from a printer. There is a method in which a predetermined amount of image data is read at the maximum speed of the scanner and stored in a memory. In this case, after reading is started by the synchronization signal of the printer, image data is read at high speed while counting the number of data request signals REQ or data response signals ACK of the interface by the drive signal counter 8 shown in FIG. Stop reading when it is done. This method does not require a transmitter having a fixed period for reading an image, and immediately issues an ACK to the REQ, so that reading can be performed at the maximum speed of the scanner.

As another embodiment, the number of dots or the amount of image data for one line is set and stored in the counter 8 in advance, and the number of the counter is read in one line. When this method is used, in the embodiment, reading can be performed by the counter only with a predetermined number, but in this embodiment, a plurality of numbers can be set, and even if the size of the medium changes, it can be handled. be able to.

Although the above is an embodiment for synchronizing image data of a page printer such as a laser printer, a serial printer including an ink-jet printer synchronizes image data with the following embodiment.

In the case of a serial printer, printing is generally performed by moving a plurality of nozzles by a motor capable of minute displacement such as a stepping motor. Therefore, synchronization is achieved based on the drive pulse used for driving the stepping motor or the position detection signal generated according to the displacement of the motor.
Transfer image data. In this case, a synchronization signal counter 9 shown in FIG. 5 is provided to detect where the current position is from the number of pulses from the past origin and the time.

In addition, a signal generated at the phase origin of the motor is used, or a signal from a sensor for detecting the mechanical position of the print head is used. In these methods, since an electrical or mechanical origin is obtained, an image can be read while synchronizing with reducing an absolute displacement (not shown).

When performing multicolor copying or copying at high resolution,
The amount of image data sent from the scanner to the printer is enormous, and the image transfer may not be able to keep up with the printing speed required by the printer. To improve it, use a wide and fast interface as possible. For example, rather than the traditional bidirectional parallel interface,
SCSI interface, FastSCSI, WideSCSI,
It is necessary to read an image according to the printing speed of a printer by using an interface called UrtraSCSI, which has a high speed and a large number of data lines.

In the above description, a page printer and a serial printer have been described as image output means. Although a scanner has been described as the image input means, it is possible to have an image input device such as a digital still camera or a video camera as described above. An image input device having an image memory such as a digital still camera often transfers data in the same manner as a scanner, and can perform copying in a similar manner. Some products use a serial interface that performs serial data transfer.In this case, reduce the number of tones reproduced by the output device and try binary processing including spatial modulation such as pulse width modulation. It is preferable to use a method of enlarging an image so as to enlarge the dots to be printed and copying the image with a small amount of image data.

As an embodiment showing the features of the present invention, an embodiment effective for enlarging an image will be described. In the above case, 1
When one line of image data is input, one line of image data is output on the other side. In the present invention, the same data and two or more lines can be output for one line of input. For example, when outputting two lines, it is sufficient to output two lines of image data at intervals at which one line of image data is input. Conversely, the scanner only needs to read one line of image data while outputting two lines of image data. Therefore, in this case, since the synchronization signal from the printer is twice for one line, a synchronization signal counter that outputs one signal with two signals is required.
Similarly, image data may be output a plurality of times according to the degree of enlargement.

[0037]

According to the present invention, a plurality of memories are used based on a synchronization signal of an image output means, and one of the memories inputs image data from the image input means and instantly inputs the image data from the other memory. Since the output is performed, the copying speed is high, and since there is no frame memory, a low-cost, high-definition, high-quality print image can be obtained.

Further, since the image can be output a plurality of times while the image is being input to the memory, the image can be easily enlarged.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention which inputs or outputs to two sets of line memories in synchronization with a synchronization signal of an image output unit.

FIG. 2 is an explanatory diagram of a conventional example that requires a central processing unit between an image input unit and an image output unit.

FIG. 3 is an explanatory diagram of an embodiment in which a pixel synchronization signal Wclk required by a printer and a drive signal for driving a scanner are different clocks.

FIG. 4 is an explanatory diagram of an embodiment in which a counter for counting the number of pulses of a data request signal and a data response signal transmitted and received by an interface is provided.

FIG. 5 is an explanatory diagram of an embodiment in which a counter for counting a predetermined time or the number of pulses from a synchronization signal transmitted from a printer is provided.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image input means, 3 ... Image output means, 4 ... Drive signal oscillation circuit, 5a, 5b ... Memory, 6 ... Image data from a scanner, 7 ... Image data to a printer, 10 ... Switching means.

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Yoshinobu Fukano 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd.

Claims (3)

[Claims] 1. A copying apparatus comprising: an image input means for reading an image and converting the image data into image data; an image output means for converting the image data into a printed image; and a general-purpose interface for transferring data therebetween. A memory of a plurality of lines is provided between the image output means and one or more of the memories outputs data to the image output means in synchronization with a synchronization signal of the image output means. The memory of the line or more is provided with switching means for switching the input / output direction so as to input the image data from the image input means in synchronization with the synchronization signal of the image output means, and the image data from the image input means is provided. An image input / output interface, comprising a drive signal oscillation circuit for oscillating a drive signal for input. 2. An image input means for reading an image and using the image data as image data; an image output means for converting the image data into a printed image;
In a copying apparatus having a general-purpose interface for transferring data therebetween, a memory having a plurality of lines or more is provided between the interface and the image output device, and at least one line of the memory is synchronized with a synchronization signal of the image output means. Switching means for outputting data to the image output means, and switching the input / output direction so as to input image data from the image input means in synchronization with a synchronization signal of the image output means. And a counter capable of arbitrarily setting the number of pixels to be read on one or more lines, and generating a drive signal to the image input means by a predetermined number set in the counter based on a synchronization signal of the image output means. An image input / output interface comprising a drive signal generation circuit. 3. A synchronizing signal for operating said switching means for a predetermined time or a predetermined number of pulses based on at least one of a horizontal synchronizing signal, a vertical synchronizing signal and a pixel synchronizing signal of said image output means. 3. The image input / output interface according to claim 1, further comprising a synchronizing means for generating the image.