JPH0974454A - Image processing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain interfacing between each of a scanner unit and a printer unit with a system control unit through standard bus configuration without notifying a characteristic of the scanner unit or the printer unit. SOLUTION: A command group data bus and an image data group data bus of an interface circuit interfacing a system control unit 1, a scanner unit 2 and a printer unit 3 are configured by a system bus 6 being a common data bus. For example, an asynchronous first-in first-out memory is provided to an input output section of the scanner unit 2 and the printer unit 3 and data transfer between the units 2, 3 is conducted asynchronously with an actual transfer clock system in each unit. Furthermore, the transfer speed of the interface circuit is selected faster than an actual data input output transfer speed of the units 2, 3 and image data are transferred between the units with division.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing system for electrically handling image information such as a digital copying machine and a facsimile.

[0002]

2. Description of the Related Art Generally, in an image processing system such as a digital copying machine, a scanner unit (SCN) which is an image reading unit which optically reads an image of a document (target image) and converts it into image data, and a scanner unit. The printer unit (PRN), which is an image forming unit that forms an image on paper based on the image data from, is operated by the same basic clock or line synchronization signal, and the scanner unit and the printer unit are reliably synchronized. Accurate image reproduction is performed on paper.

By the way, although it is convenient to use the bus of the interface circuit connecting each unit for exclusive use of image data, it is not suitable for command data (including status). Further, since the data transfer between the units is performed in a completely synchronized form, once the image data transfer period is entered, no command data can be sent until the end of the frame. Even if an error occurs in either the scanner unit or the printer unit on the way, let alone the partner unit,
No information is transmitted to the system control unit that controls each unit in a centralized manner.

For that reason, in the conventional image processing system, as shown in FIG. 5, for example, the system control unit 1, the scanner unit 2, and the printer unit 3 are commonly used by the data bus (video interface) 4 of the image data system. In addition to the connection, it is common to connect the system control unit 1, the scanner unit 2 and the printer unit 3 with a command data bus 5.

[0005]

However, in such a conventional image processing system, each unit must be connected with the specifications of the transfer basic clocks of both the input and output systems being the same. If each unit is physically separated, prepare a cable containing the image data data bus and a cable containing the command data bus as cables for connecting them. It had to be done and the cost was high.

In the case where the scanner unit and the printer unit are separated from each other and, for example, the connection interface between the units does not include a basic clock or a line synchronization signal, the scanner unit and the printer unit are buffered. It is conceivable to connect via a memory, and a page memory is generally used as an example of the buffer memory, but when the resolution is high or when four color simultaneous scanning is performed, the memory capacity becomes large. Furthermore, the cost becomes higher.

Alternatively, when the memory capacity is small, since there is no signal of the synchronous system, the scanner unit and the printer unit receive a copy start command from the system control unit or start copying by exchanging commands with each other. However, each unit still has a problem of variation in time peculiar to each unit from the actual reception of an instruction to the actual transfer of image data.

If a combination of a scanner unit, a printer unit, and a system control unit is used to sufficiently adjust the timing of the start time and variations, it is possible to construct a system that can absorb the variations in the buffer memory. Naka 1
The above adjustment is required every time one unit is changed to a new model or the characteristics are changed. This diminishes the merit of adopting a bus configuration that wants to connect each unit asynchronously, and requires special tuning each time the unit to be combined changes.

The present invention has been made in view of the above points, and in an image processing system using a scanner unit and a printer unit that operate independently of each other,
An object of the present invention is to enable interface connection between each unit and the system control unit with a standard bus configuration without paying attention to the characteristics of the scanner unit or the printer unit. In addition, it is possible to reliably transfer various data such as commands, statuses, and image data between the above units,
It is also intended to make it easy to update and change the unit without compromising the advantages of standard interface connection.

[0010]

In order to achieve the above object, the present invention provides an image reading unit for optically reading a target image and converting it into image data, and a sheet on a sheet based on the image data from the unit. In an image processing system including an image forming unit that forms an image and a system control unit that controls each unit in an integrated manner, a command system data bus and an image data system data bus of an interface circuit that connects the units are provided. It is configured by a common data bus.

Further, it is preferable that the data transfer between the units is performed asynchronously with the actual transfer clock system in each unit. In this case, it is desirable to equip the input / output units of the image reading unit and the image forming unit with asynchronous first-in first-out memory.

Further, it is preferable to provide means for making the transfer speed of the interface circuit higher than the actual data input / output transfer speed of the image reading unit and the image forming unit. In this case, the image reading unit and the image forming unit are provided with a means for ensuring a bus-free period in which the common data bus is in a free state during the transfer period of image data, and an image such as a command is further provided during the bus-free period. It is preferable to provide a means for transferring data other than the data.

In the image processing system of the present invention, the command data bus and the image data data bus of the interface circuit connecting the image reading unit, the image forming unit and the system control unit are constituted by a common data bus, so that the Cost can be realized.

Furthermore, if the data transfer (interface) between the units is performed asynchronously with the actual transfer clock system in each unit, an image reading unit (scanner unit) or an image forming unit (printer unit). ) Command (status) between units without paying attention to the characteristics (synchronization timing) of
Also, various data such as image data can be reliably transferred.

Moreover, the unit can be easily updated or changed without losing the merit of the standard interface connection by the common data bus. In this case, the input / output units of the image reading unit and the image forming unit are provided with asynchronous first-in first-out memory to absorb the difference between the transfer speeds of the input / output clock system of the main body of each unit and the transfer clock system of the interface circuit. be able to.

If the transfer speed of the interface circuit is set higher than the actual data input / output transfer speed of the image reading unit and the image forming unit, the image data can be divided and transferred between the units. . In this case, each of the units secures a bus-free period during which the common data bus is in a free state during the transfer period of the image data (free time that can be obtained by division transfer). If data other than image data can be transferred, other data such as commands and statuses can be transferred between the units even during the image data transfer period.

Therefore, during the transfer period of the image data, for example, when an abnormality occurs in either the image reading unit or the image forming unit, it is possible to inform the partner unit or the system control unit of the status for notifying the abnormality. it can. Further, the system control unit can send the next command to each of the other units while the image data is normally transferred between the image reading unit and the image forming unit. improves.

[0018]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a block diagram showing an example of an image processing system embodying the present invention, and the same parts as those in FIG. 5 are designated by the same reference numerals.

This image processing system comprises a system control unit 1, a scanner unit 2 and a printer unit 3, which are connected by a system bus (command system data bus + image data system data bus) 6 which is a common data bus. Connected. Here, as an example of the configuration of each of the units 1 to 3, SCSI is connected to the system bus 6.
The case where (small computer system interface) is adopted will be described.

The system control unit 1 centrally controls the entire system, that is, the scanner unit 2 and the printer unit 3. The simplest configuration of the system control unit 1 includes only the MPU section, the operation section, and the SCSI section. Further, as a high-grade device, there is a device in which the SCSI of a personal computer equipped with a page memory is connected as a system bus.

The scanner unit 2 is constituted by a well-known technique such as a reading system unit and a SCSI section. The scanner unit 2 optically reads an image of a document, converts it into image data, performs a predetermined image processing on the image data, and then transfers the image data to another unit through the SCSI unit.

The printer unit 3 is composed of a well-known technique such as a writing system unit (including a paper transport mechanism) for a color image or a monochrome image and a SCSI unit.
The printer unit 3 takes in image data from the scanner unit 2 by the SCSI unit and forms an image on a sheet based on the image data.

FIG. 2 is a block diagram showing an internal configuration example of the scanner unit 2. The SCSI unit (interface circuit) 11 is composed of a SCSI controller, and is a normal S
The CSI control is performed, and the read image data is transferred to the printer unit 3 via the system bus 6 when the read command is executed. This transfer rate (transfer speed)
Is Y (byte / s). In order to perform the transfer, a DMA request is issued to the DMA (direct memory access) controller unit 12.

When the DMA request is issued from the SCSI section 11, the DMA controller section 12 reads the image data stored in the FIFO section 14 unless a stop signal is sent from the FIFO status generation section 13, and Is written in the SCSI unit 11. FIFO section 1
4 is a first-in memory used as a line memory
It is composed of a first-out field memory (first-in first-out memory), and writing and reading of image data are performed by asynchronous transfer clocks.

The FIFO status generator 13 counts the amount of data written from the reading system unit (IPU) 15 to the FIFO unit 14 and the amount of data read from the FIFO unit 14 by the DMA controller unit 12 to obtain the difference. , The FIFO unit 14 is compared with the memory capacity of the FIFO unit 14 to notify the MPU unit 16 in real time of various information such as empty (empty), half (half), and full (full). Further, if empty at the same time, a stop signal is output to the DMA controller unit 12.

The reading system unit 15 is composed of a light source, a filter, a photoelectric conversion element, an A / D converter, etc., and uses a filter to obtain color image data. The image data is subjected to predetermined image processing, and the image data is transferred to the FIFO unit 14 for writing. In addition,
This read transfer rate (transfer speed) is X (byte / s)
And The MPU unit 16 is composed of a central processing unit (CPU) and peripheral circuits for controlling the entire scanner unit 2.

FIG. 3 is a block diagram showing an example of the internal configuration of the printer unit 3. The SCSI unit 21 is composed of a SCSI controller, performs normal SCSI control, receives image data transferred from the scanner unit 2 via the system bus 6 when a read command is executed, and sends a DMA request to the DMA controller unit 22. Request.

When the DMA request is issued from the SCSI unit 21, the DMA controller unit 22 reads out the image data received by the SCSI unit 21 unless the stop signal is sent from the FIFO status generation unit 23, and the FIFO unit reads it. It is transferred to the section 24 and written. FIF
The O unit 24 is composed of a first-in first-out field memory (first-in first-out memory) used as a line memory, and writes and reads image data by asynchronous transfer clocks.

The FIFO status generation unit 23 uses the DMA
The amount of data written in the FIFO unit 24 by the controller unit 22 and the FIFO by the write system unit 25
The amount of data read from the O unit 24 is counted, the difference is obtained, and various information such as empty, half, and full is notified to the MPU unit 26 in real time while comparing with the memory capacity of the FIFO unit 24. In addition, when both are full at the same time, a stop signal is output to the DMA controller unit 22.

The writing system unit 25 includes a FIFO unit 2
4. Image data is read from 4 and transferred, laser light corresponding to this image data is emitted to expose a pre-charged photoconductor, and toner is attached to the photoconductor to form a visible image, and then the toner image is It is transferred onto a sheet of paper and then subjected to heat fixing processing to accurately reproduce the image on the sheet of paper, and the copy paper is ejected to a paper ejection tray outside the machine. The write transfer rate (transfer rate) is X (byte / s).

The MPU section 26 is used for the printer unit 3
It is composed of a central processing unit (CPU) and peripheral circuits that control the entire system. FIG. 4 is a diagram showing an example of the relationship between the processing time relating to the data transfer between the scanner unit 2 and the printer unit 3 and the data storage amount of the FIFO unit 14 of the scanner unit 2.

In this figure, N is the scanner unit 2
The transfer amount (byte) of one image data to the printer unit 3 by the SCSI unit 11 of X is a read transfer rate (byte / s) by the reading system unit 15 of the scanner unit 2 and the writing system unit of the printer unit 3. Write transfer rate (byte / s) according to 25
Is the transfer rate (byte / s) by the interface circuit (the SCSI units 11 and 12 and the system bus 6) of the scanner unit 2 and the printer unit 3, and N-A is the amount of data stored in the FIFO unit 14 at the start of image data transfer. (By
te) respectively.

The leftmost point on the time axis is the scanning (reading) start point by the reading system unit 15, and the point on the time axis 0 is the transfer start point by the SCSI unit 11. Further, the slope of the broken line to the right is the slope of X, and the slope of the broken line to the right is the slope of Y. The downward slope to the right of the thick diagonal line is the (Y-X) slope. And the relation of the following formulas is materialized. However, Y> X.

A = X * N / Y N / Y = (NA) / (YX) N / X = (NA) / (YX) + (NA) / X

Next, an operation example of the copy sequence in this image processing system will be described. (1) The system control unit 1 transfers the transfer mode information to the scanner unit 2 and the printer unit 3 together with the copy start command.

(2) The printer unit 3 has a predetermined SC
If the writing unit 25 is in the ready state through the SI sequence, a read command is issued to the scanner unit 2 to request the transfer of image data. (3) The scanner unit 2 starts scanning a document, reads the image, and sequentially transfers the read image data to the FIFO unit 14 to write the image data.

(4) The scanner unit 2 activates the DMA controller section 12 when (NA) bytes of image data are accumulated in the FIFO section 14 as shown in FIG.
The image data is read out, sent to the SCSI unit 11, and transferred to the printer unit 3 via the system bus 6. When the printer unit 3 starts receiving image data from the scanner unit 2, the printer unit 3 delays the time required for timing adjustment and then activates the writing system unit 25 to start image formation.

(5) The scanner unit 2 transfers N-byte image data as shown in FIG.
Since 4 becomes empty, a bus free period for keeping the system bus 6 in a free state is secured. Even during this bus-free period,
The read image data is transferred to the FIFO unit 14 one after another and continues to be stored.

On the other hand, Nbyte in the printer unit 3
After the image data is received, since more data than the amount of data output to the writing system unit 25 remains in the FIFO unit 24 during the bus free period, the writing unit from the FIFO unit 24 also remains during the bus free period. The image data is continuously transferred to 25.

Further, during the bus-free period, both the scanner unit 2 and the printer unit 3 can transfer command system data, and if any abnormality occurs, a command to stop image data transfer or read the next original. Information about the transfer of image data can also be transferred in advance.

(6) Here, returning to (2), the above sequence is repeated again. When the transfer of the read image data for one page (for example, one original) is completed,
Proceed to (7). (7) If the next page (for example, the next original) is present after the termination process is performed, the process returns to (1) and the same sequence as described above is repeated. Otherwise, it will be in a standby state.

[0042]

As described above, according to claims 1 to 3.
According to the image processing system of the present invention, each unit and the system control unit can be used as a general-purpose data bus without being aware of the image data system data bus (video interface) of the image reading unit and the image forming unit and the synchronization timing. Since it can be connected by (system bus), various data can be reliably transferred between the units.

Further, according to the image processing system of the inventions of claims 4 to 6, it is apparently possible (at a practical level) to transfer command data even during transfer of image data between the units. Become.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of an image processing system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration example of a scanner unit 2 in FIG.

FIG. 3 is a block diagram showing an internal configuration example of the printer unit 3 in the same manner.

4 is a processing time relating to data transfer between the scanner unit 2 and the printer unit 3 and the scanner unit 2; FIG.
3 is a diagram showing an example of a relationship with the data storage amount of the FIFO unit 14 of FIG.

FIG. 5 is a block diagram showing an example of a conventional image processing system.

[Explanation of symbols]

 1: System control unit 2: Scanner unit 3: Printer unit 6: System bus 11,21: SCSI part 12, 22: DMA controller part 13, 23: FIFO status generation part 14, 24: FIFO part 15: Reading system unit 16 , 26: MPU section 25: Writing system unit

Claims (6)

[Claims] 1. An image reading unit that optically reads a target image and converts it into image data, an image forming unit that forms an image on a sheet based on the image data from the unit, and an integrated unit for each unit. An image processing system including a system control unit for controlling the image processing system according to claim 1, wherein the command data bus and the image data data bus of the interface circuit connecting the units are configured by a common data bus. . 2. The image processing system according to claim 1, wherein data transfer between the units is performed asynchronously with an actual transfer clock system in each unit. 3. The image processing system according to claim 2, wherein the image reading unit and the image forming unit have an asynchronous first-in first-out memory in an input / output unit. 4. The image processing system according to claim 1, further comprising means for increasing a transfer speed of the interface circuit to be higher than an actual data input / output transfer speed of the image reading unit and the image forming unit. Characteristic image processing system. 5. The image processing system according to claim 4, wherein the image reading unit and the image forming unit secure a bus-free period in which the common data bus is in a free state during a transfer period of image data. An image processing system comprising: 6. The image processing system according to claim 5, wherein the image reading unit and the image forming unit have means for transferring data other than image data such as a command during the bus-free period. Image processing system.