JP2001197237A - Mfp device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the load on the bus in an MFP device. SOLUTION: A scanner 1 provided in this MFP device consists of a read part 2 which reads an original image and outputs the image as image data, a distortion correcting part 3 performing distortion correction of the image data from the part 2, a density converting part 4 applying density conversion of the image density to the image data subjected to distortion correction from the part 3, an N value making part 5 making the image data from the part 4 an N value (N is a >=2 natural number) and a DMA part 6 outputting the image data from the part 5 to a bus. The operation clocks of the parts 2 and 3 are defined as a clock A, the operation clocks of the parts 5 and 6 are defined as a clock B, the frequencies of the clocks A and B are made optionally settable, and the bus burden is reduced by enhancing the performance of the DMA bus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an MFP apparatus having a facsimile function, a printer function, a scanner function, etc., and more particularly to an MFP apparatus which reduces the load on a bus provided to make these functions function in a unified manner. About.

[0002]

2. Description of the Related Art At present, MFP devices having a facsimile function, a printer function, a scanner function, and the like are on the market, and as a further requirement, there is an MFP device which can be connected to, for example, a personal computer.

An example of such an MFP apparatus is an image forming apparatus such as a facsimile apparatus.

The facsimile apparatus includes a scanner unit that reads an original image and outputs the image data as image data, a communication unit that communicates the image data with an external device via a telephone line or the like, a printer unit that prints the original image based on the image data, It has a control unit for controlling the movement.

[0005] The scanner unit, the printer unit, and the like are connected by a single bus, and control signals and image data are transmitted on the bus to realize a unified function.

However, as described above, since a large amount of data is transmitted to the bus, there is a problem that the load on the bus is increased and the processing speed is reduced.

In particular, when it is desired to read a high-density and high-definition image as in recent years, a large amount of data is output from the scanner unit to the bus. Needs to be shortened (DMA request interval).
If the A request interval is shortened, the load on the bus increases.

Therefore, Japanese Patent Application Laid-Open No. 5-130303 discloses a configuration in which the bus is divided into a control bus and an image bus to reduce the load on the bus.

In Japanese Patent Application Laid-Open No. Hei 7-30746, when performing density conversion processing of a printer device, writing to a page memory at a first frequency corresponding to the input image density is performed.
A configuration in which data is read from a page memory at a second frequency corresponding to the plotter density and density conversion processing is performed on the data is disclosed, thereby enabling high-speed printing speed processing and the like.

[0010]

However, in the configuration disclosed in Japanese Patent Application Laid-Open No. 5-130303, it is necessary to divide the bus into two systems, which causes a problem that the cost is increased.

In the configuration disclosed in Japanese Patent Application Laid-Open No. 7-30746, data rate and density conversion processing is performed via a page memory, and the data rate must be uniquely determined by the density. Therefore, the second frequency is determined by the density of the printer engine and its recording speed, and the first frequency is determined by the ratio of the density of the input image to the density of the printer engine.

Therefore, even in such a configuration, it becomes difficult to perform density conversion processing on the read image data and arbitrarily set the data rate to the bus irrespective of the image density, and to sufficiently reduce the load on the bus. There is a problem that can not be.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an MFP apparatus capable of reducing the load on a bus without dividing the bus into a plurality of systems.

[0014]

According to an aspect of the present invention, there is provided a scanner function such as a scanner function including a scanner, a facsimile function including a communication unit, and a printer function including a printer. In an MFP apparatus having at least one or more functions other than those described above, and each of these functions is connected by a single bus, the scanner function determines the read clock frequency when reading an image, the read image frequency, It operates at two clock frequencies, the output clock frequency when outputting data to the bus,
Further, the frequency of the read clock and the output clock can be arbitrarily set, so that the load on the bus can be reduced.

According to a second aspect of the present invention, the scanner section comprises:
A reading unit that reads an original image and outputs it as image data, a distortion correction unit that performs distortion correction on image data from the reading unit, and a distortion correction unit that performs distortion correction on the image data from the distortion correction unit. A density conversion unit for performing a density conversion process of image density, an N-value unit for converting the image data from the density conversion unit into N values (N is a natural number of 2 or more), and an image data from the N-value unit. And a DMA unit that outputs the clock to the bus, wherein the operation clocks of the reading unit and the distortion correction unit are used as the read clock, and the operation clocks of the N-value conversion unit and the DMA unit are used as the output clocks.

According to a third aspect of the present invention, the density conversion section comprises:
A toggle line buffer, a write unit that operates on the same read clock as the distortion correction unit and writes the image data from the distortion correction unit to the toggle line buffer, and a toggle unit that operates on the same output clock as the N-value conversion unit A read section for reading out the image data stored in the line buffer and outputting the read out image data to the N-value conversion section.

According to a fourth aspect of the present invention, the reading unit is a CCD image sensor or CI that converts image information into an electric signal.
An image sensor such as an S image sensor is provided, and the frequency of the read clock is set to the operation clock frequency of the image sensor.

The invention according to claim 5 is characterized in that the frequency ratio between the read clock and the output clock can be set according to the load state of the bus.

The invention according to claim 6 is characterized in that the frequency ratio between the read clock and the output clock can be set according to the state of the transmission destination for transmission via the bus.

A seventh aspect of the present invention is characterized in that the frequency ratio between the read clock and the output clock can be set according to the status of each function such as a facsimile function, a printer function, and a scanner function.

The invention according to claim 8 is characterized in that the frequency of the output clock can be set according to the number of active DMA channels.

The invention according to claim 9 is characterized in that the frequency of the output clock can be set according to the bus performance.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of the MFP apparatus according to the present invention.

The MFP apparatus includes a scanner unit 1 for reading a document image and converting the image data into image data, a communication unit 8 for communicating the image data with the outside via a telephone line or the like, and a printer unit 7 for printing a document image based on the image data. And a memory unit 10 for storing image data, programs for the control unit 9, etc., which are connected by a DMA bus to provide a facsimile function, a printer function, and a scanner function. It is realized in a unified manner.

The scanner unit 1 includes a reading unit 2, a distortion correction unit 3,
It has a density conversion unit 4, an N-value conversion unit 5, and a DMA unit 6, and DMA-outputs image data to a bus.

The reading section 2 is composed of an image sensor such as a CCD image sensor or a CIS (contact) image sensor, not shown, and an A / D converter. The image sensor converts document information into an electric signal, and converts this into an A / D signal. The data is converted into multi-value data by a D converter and output.

The distortion correction unit 3 performs shading correction and dark level correction on the multi-value data, and the density conversion unit 4 performs density conversion processing on the image data on which such distortion correction has been performed.

The N-value converting section 5 performs multi-stage threshold processing, multi-value error diffusion processing, and the like on the image data after the density conversion to generate N-value data. Note that N is a natural number of 2 or more.

The N-value data generated in this way is
The data is output from the DMA unit 6 to the DMA bus.

The printer 7 is connected to a DMA bus,
An image is formed (printed) based on the image data received via the DMA bus.

On the other hand, the communication section 8 is connected to the DMA bus and transmits image data transmitted via the DMA bus via a telephone line or the like. Further, it receives image data and the like via the telephone line or the like and outputs it to the DMA bus.

The image data read in this way and the received image data are stored in the memory unit 10 as needed.
, And all these movements are controlled by the control unit 9.

In such a configuration, the DMA bus includes:
Since the control signal and the image signal are transmitted together, the DMA
The burden on the bus will increase.

Therefore, in the present invention, it is possible to arbitrarily set the frequencies of the operation clocks of the reading unit 2 and the distortion correction unit 3 before the density conversion and the operation clocks of the N-value conversion unit 5 and the DMA unit after the density conversion. Thus, the operation performance of the bus is enhanced to reduce the burden on the bus.

The operating clocks (reading clocks) of the reading unit 2 and the distortion correcting unit 3 are described as a clock A, and the operating clocks (output clocks) of the N-value converting unit 5 and the DMA unit after density conversion are described as a clock B. Describe.

For this reason, as shown in FIG. 2, the density conversion section 4 comprises a write section 41, a read section 42, and a toggle line buffer 43.

The write section 41 operates with the clock A, and writes input data to the toggle line buffer 43 as it is at the time of enlargement, and writes while thinning out the input data at the time of reduction.

On the other hand, the read section 42 operates with the clock B, and reads the address from the toggle line buffer 43 while enlarging the address at the time of enlargement, and reads the address as it is at the time of reduction.

The toggle line buffer 43 is a two-line line buffer. When one is written, the other is read, and the read and write are repeated for each line.

FIG. 3 is a timing chart of the clock A, the clock B, and the line synchronization signal (line sync). The line synchronization signal is a synchronization signal indicating one line of the read data. B can be set to an arbitrary frequency.

Then, an image sensor such as a CCD image sensor or a CIS image sensor of the reading unit 2 is set to output data at clock A.

When data is output from the DMA unit to the DMA bus, the frequency of the clock B is changed according to the bus load.

With the above configuration, the clock can be set arbitrarily before and after the density conversion, and the data rate at the time of output to the DMA bus can be arbitrarily set regardless of the image density. The burden on the DMA bus can be reduced.

At this time, since the density conversion unit 4 is composed of the write unit 41 to the toggle line buffer 43 for performing the reduction process and the read unit 42 from the toggle line buffer 43 for performing the enlargement process, the clock A before the density conversion is used. It is possible to provide a simple configuration divided into a system block and a clock B system block after density conversion.

It should be noted that the frequency of the clock B may be changed in accordance with the destination of transmission from the DMA unit via the DMA bus and the state thereof.

For example, when transmitting image data to the printer 7 or the memory unit 10 which can operate at high speed, the clock B
When the image data is transmitted to the communication unit 8 operating at a low speed, the frequency of the clock B is reduced.

Of course, it goes without saying that the frequency of the clock B may be changed according to the functions of the MFP device.

Further, the frequency of the clock B may be changed according to the number of operating DMA channels.

For example, the frequency of the clock B is made slower as the number of operating channels is larger in one-channel operation, two-channel operation, three-channel operation, and the like.

The DMA channel includes a transfer channel from the scanner unit 17 to the memory unit 10, a transfer channel from the communication unit 8 to the memory unit 10, a transfer channel from the memory unit 10 to the printer unit 7, and a transfer channel from the memory unit 10. There is a transfer channel to the communication unit 8 and the like.

The frequency of the clock B may be changed according to the performance of the transmission of the MFP device to the DMA bus.

For example, when the same circuit configuration is adopted in two different MFP devices, the lower the DMA transfer performance, the slower the frequency of the clock B between the MFP device with high DMA transfer performance and the MFP device with low DMA transfer performance. I do.

[0053]

As described above, according to the first aspect of the present invention, there are two types of clock frequencies: a read clock frequency at which the scanner function reads an image and an output clock frequency at which the read image data is output to a bus. , And the read and output clock frequencies can be set arbitrarily, so that the load on the bus is reduced and high-speed processing becomes possible.

According to the second aspect of the invention, the scanner unit 1 reads a document image, a distortion correction unit that performs distortion correction on image data from the reading unit, A density conversion unit that performs a density conversion process of image density on the image data on which the distortion correction has been performed, and an N-value conversion unit that converts the image data from the density conversion unit into an N-value (N is a natural number of 2 or more). , Which outputs image data from the N-value conversion unit to a bus.
Since it is constituted by the MA unit, the read clock frequency of the reading unit and the distortion correction unit, the N-value conversion unit and the DMA
The output clock frequency of the unit can be arbitrarily set.

According to the third aspect of the present invention, the density conversion unit operates at the same read clock frequency as the toggle line buffer and the distortion correction unit, and the image data from the distortion correction unit is written into the toggle line buffer. The write unit and the read unit that operate at the same output clock frequency as the N-value conversion unit, read out image data from the toggle line buffer, and output the read image data to the N-value conversion unit have simple clock frequency differences. Adjustment can be performed, thereby reducing the load on the bus and enabling high-speed processing and the like.

According to the fourth aspect of the present invention, a CCD image sensor or CI for converting an image into an electric signal is provided to the reading unit.
Since an image sensor such as S or an image sensor is provided and the read clock frequency is set to the operation clock of the image sensor, the load on the bus can be reduced with a simple configuration.

According to the fifth aspect of the present invention, since the frequency ratio between the read clock and the output clock can be set according to the load state of the bus, the load on the bus can be reduced and high-speed processing can be performed. become.

According to the sixth aspect of the invention, the frequency ratio between the read clock and the output clock can be set according to the state of the transmission destination transmitted via the bus.
The performance of the bus is improved, the load on the bus can be reduced, and high-speed processing can be performed.

According to the present invention, the frequency ratio between the read clock and the output clock can be set according to the state of each function such as the facsimile function, the printer function, and the scanner function. , The load on the bus can be reduced, and high-speed processing can be performed.

According to the eighth aspect of the present invention, the frequency of the output clock can be set according to the number of DMA channels in operation, so that the performance of the bus is improved, the load on the bus can be reduced, and the speed of the bus can be reduced. Processing can be performed.

According to the ninth aspect of the present invention, the frequency of the output clock can be set according to the performance of the bus. Therefore, the performance of the bus is improved, the load on the bus can be reduced, and high-speed processing can be performed. Becomes possible.

[Brief description of the drawings]

FIG. 1 is an MFP applied to a description of an embodiment of the present invention.
It is a block diagram of an apparatus.

FIG. 2 is a block diagram of a scanner unit.

FIG. 3 is a timing chart of a clock signal.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 scanner unit 2 reading unit 3 distortion correction unit 4 density conversion unit 5 N-value conversion unit 6 DMA unit 7 printer unit 8 communication unit 9 control unit 10 memory unit 41 write unit 42 read unit 43 toggle line buffer

Claims (9)

[Claims] At least one function other than the scanner function, such as a scanner function provided with a scanner, a facsimile function provided with a communication unit, and a printer function provided with a printer, is provided.
An MFP device having the above functions, wherein each of these functions is connected by a single bus, wherein the scanner function stores a read clock frequency for performing image reading, and the read image data on the bus. An MFP apparatus which operates at two clock frequencies, namely an output clock frequency at the time of output, and wherein the read clock and output clock frequencies can be set arbitrarily. 2. A scanner, wherein the scanner reads a document image and outputs the read image as image data; a distortion corrector that performs distortion correction on image data from the reader; A density conversion unit that performs a density conversion process of image density on the image data on which the distortion correction has been performed; and an N-value conversion unit that converts the image data from the density conversion unit into an N-value (N is a natural number of 2 or more). DM for outputting the image data from the N-value conversion unit to the bus
2. The apparatus according to claim 1, further comprising an A section, wherein an operation clock of the reading section and the distortion correction section is used as the read clock, and an operation clock of the N-value section and the DMA section is used as the output clock. MFP device. 3. The toggle conversion unit, wherein the density conversion unit operates with the same read clock as the distortion correction unit and writes the image data from the distortion correction unit into the toggle line buffer. 3. The read unit according to claim 2, further comprising a read unit that operates at the same output clock as the N-value conversion unit, reads out image data stored in the toggle line buffer, and outputs the read image data to the N-value conversion unit. MFP device. 4. The reading section has an image sensor such as a CCD image sensor or a CIS image sensor for converting image information into an electric signal, and a frequency of the reading clock is set to an operation clock frequency of the image sensor. The MFP device according to claim 1, wherein: 5. The MFP apparatus according to claim 1, wherein a frequency ratio between the read clock and the output clock can be set according to a load state of the bus. 6. The apparatus according to claim 1, wherein a frequency ratio between the read clock and the output clock can be set according to a state of a transmission destination to be transmitted through the bus. MFP device. 7. The apparatus according to claim 1, wherein a frequency ratio between the read clock and the output clock can be set according to a state of each function such as a facsimile function, a printer function, and a scanner function. MF according to item 1
P device. 8. The frequency of the output clock is set to D
5. The MFP apparatus according to claim 1, wherein the setting can be performed according to the number of MA channels. 9. The MFP apparatus according to claim 1, wherein a frequency of said output clock can be set according to a performance of said bus.