JP3618420B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a digital copying machine having a page memory.
[0002]
[Prior art]
In recent years, image information has been easily handled as digital data.
[0003]
There is a digital PPC (plain paper copier) as a device to which these are applied. This is not the case where the reflected light from the original is optically guided to form an image on the photosensitive member as in the case of the conventional analog PPC. Reflected light from the original is once read as an electrical signal by a CCD sensor and then converted into a digital signal. Once the digitized document is subjected to various processes, it is output to paper by a laser printer.
[0004]
Once the original image is converted into a digital signal, various processes such as correction of input characteristics from the CCD sensor and output characteristics to the laser printer, enlargement / reduction, partial erasure, and out-of-frame erasure can be performed by signal processing.
[0005]
Furthermore, an image converted into a digital signal can be efficiently stored by compressing the data amount by performing an encoding process. The stored images can be decoded into original images in any order in which print output is desired, and can be output to an arbitrary number of laser printers.
[0006]
Conventionally, these rearrangements have been mechanically performed on a copied print output by using a sorter or a stacker. Therefore, the enlargement of the apparatus and the increase in noise have been unavoidable. In order to print a plurality of sheets, it is necessary to repeatedly perform a copying operation.
[0007]
Also, an image memory (work area, image area) for one page is prepared on the page memory, and an image (encoded data) encoded and stored in a file area (encoded area) of the scanner or page memory is temporarily stored. After development on the image memory of the page memory, rotated images such as 90 degrees, 180 degrees, and 270 degrees can be output by changing the reading method of the image memory.
[0008]
By rotating and outputting the image, it is possible to always output the paper in the same direction regardless of the direction in which the document is placed, or to output a plurality of cuts according to the direction of the paper by alternately outputting vertically and horizontally.
[0009]
Further, by reducing the image from the scanner or the encoded and accumulated image and developing the image in a multi-page image memory, it is possible to perform linked copying in which a multi-page image is printed on one sheet. At the time of this linked copying, the vertical and horizontal directions of the paper change depending on the number of pages to be connected, so that it is necessary to rotate the image.
[0010]
In order to rotate and output an image, it is necessary to read the image memory so that the image is rotated after the original image is once written in the image memory.
[0011]
Since the writing direction and the reading direction are different, the next image cannot be written to the image memory during this reading, and rotation reading cannot be performed unless the original image is completely developed. Due to this waiting time, the processing speed was reduced when rotating output was performed.
[0012]
In order to eliminate this waiting time, an image memory for two pages is prepared, and the next image is developed on the other available image memory while one image memory is performing rotational readout. In this way, by having two pages of image memory, it is possible to simultaneously perform development and rotation reading of an image before rotation, and by alternately performing this, it is possible to continuously perform processing without waiting for each other. Is possible.
[0013]
In order to perform the continuous processing as described above, two pages of image memory are required. In order to copy an original with high image quality, it is necessary to increase the resolution when reading the original or printing an image on a laser printer. Naturally, as the resolution is increased, the capacity of the image memory required for the resolution becomes enormous. For example, the size of the image memory required when an A4 size original is read as one page of monochrome data of 1 bit per pixel at a resolution of 400 dpi is about 2 Mbytes, and at a resolution of 600 dpi, it is about 4.4 Mbytes. In addition, when read as 8-bit grayscale data per pixel, the size becomes 8 times as large as that.
[0014]
Thus, in order to record image data, a very large memory is required. If two pages are required, there are disadvantages such as an increase in cost, an increase in the number of parts, an increase in power consumption, and an increase in apparatus size.
[0015]
[Problems to be solved by the invention]
An object of the present invention is to provide an image forming apparatus that eliminates the above-described drawbacks and can continuously process read input, encoding, decoding, and rotation / non-rotation image formation output with an image memory for one page. Objective.
[0016]
[Means for Solving the Problems]
An image forming apparatus according to the present invention includes a reading unit that reads image data of a document, a first storage unit that stores image data read by the reading unit in an image memory that stores image data for one page, and the first storage unit. First reading means for reading the image data stored in the image memory by the storage means in the non-rotating direction and the rotating direction, and the non-rotating direction image data and the rotating direction image data read by the first reading means. Encoding means for encoding, second storage means for storing the code data in the non-rotation direction and the rotation direction encoded by the encoding means in a code memory for storing code data for a plurality of pages, respectively. Decoding means for selectively decoding non-rotation direction or rotation direction code data stored in the code memory by the storage means of 2 into image data, and this decoding Third storage means for storing image data in the non-rotation direction or rotation direction decoded by the stage in the image memory, and image data in the non-rotation direction or rotation direction stored in the image memory by the third storage means An image memory comprising: a second reading means for reading; and an image forming means for forming an image on an image forming medium using image data in a non-rotating direction or a rotating direction read by the second reading means. The image data stored in the image memory is read in the non-rotating direction by the first reading means and encoded by the encoding means, and then the image data stored in the image memory is read in the rotating direction by the first reading means and encoded. The encoding is performed by means.
[0017]
An image forming apparatus according to the present invention includes a reading unit that reads image data of a document, a first storage unit that stores image data read by the reading unit in an image memory that stores image data for one page, and the first storage unit. First reading means for reading the image data stored in the image memory by the storage means in the non-rotating direction and the rotating direction, and the non-rotating direction image data and the rotating direction image data read by the first reading means. Encoding means for encoding, second storage means for storing the code data in the non-rotation direction and the rotation direction encoded by the encoding means in a code memory for storing code data for a plurality of pages, respectively. Decoding means for selectively decoding non-rotation direction or rotation direction code data stored in the code memory by the storage means of 2 into image data, and this decoding Third storage means for storing image data in the non-rotation direction or rotation direction decoded by the stage in the image memory, and image data in the non-rotation direction or rotation direction stored in the image memory by the third storage means Second reading means for reading, and image forming means for forming an image on an image forming medium using image data in the non-rotating direction or rotating direction read by the second reading means, The image data stored in the image memory by the storage means and the image data stored in the image memory by the first reading means are simultaneously read in the non-rotating direction, and the image data stored in the image memory is stored in the image memory. After reading in the non-rotating direction by the first reading means and encoding by the encoding means, the image data stored in the image memory is rotated in the rotating direction by the first reading means. It is adapted to encode the encoding means out.
[0018]
An image forming apparatus according to the present invention includes a reading unit that reads image data of a document, a first storage unit that stores image data read by the reading unit in an image memory that stores image data for one page, and the first storage unit. First reading means for reading the image data stored in the image memory by the storage means in the non-rotating direction and the rotating direction, and the non-rotating direction image data and the rotating direction image data read by the first reading means. Encoding means for encoding, second storage means for storing the code data in the non-rotation direction and the rotation direction encoded by the encoding means in a code memory for storing code data for a plurality of pages, respectively. Decoding means for selectively decoding non-rotation direction or rotation direction code data stored in the code memory by the storage means of 2 into image data, and this decoding Third storage means for storing image data in the non-rotation direction or rotation direction decoded by the stage in the image memory, and image data in the non-rotation direction or rotation direction stored in the image memory by the third storage means Second reading means for reading, and image forming means for forming an image on an image forming medium using image data in the non-rotating direction or rotating direction read by the second reading means, The storage of the image data by the storage means in the image memory and the reading of the image data stored in the image memory by the first reading means in the non-rotating direction are performed by the first reading means. The number of transfers is controlled so as not to exceed the number of transfers of data to the image memory by the first storage means, and the image data stored in the image memory is processed at the same time. After being read out in the non-rotating direction by the output means and encoded by the encoding means, the image data stored in the image memory is read in the rotating direction by the first reading means and encoded by the encoding means. .
[0019]
An image forming apparatus according to the present invention includes a reading unit that reads image data of a document, a first storage unit that stores image data read by the reading unit in an image memory that stores image data for one page, and the first storage unit. First reading means for reading the image data stored in the image memory by the storage means in the non-rotating direction and the rotating direction, and the non-rotating direction image data and the rotating direction image data read by the first reading means. Encoding means for encoding, second storage means for storing the code data in the non-rotation direction and the rotation direction encoded by the encoding means in a code memory for storing code data for a plurality of pages, respectively. Decoding means for selectively decoding non-rotation direction or rotation direction code data stored in the code memory by the storage means of 2 into image data, and this decoding Third storage means for storing image data in the non-rotation direction or rotation direction decoded by the stage in the image memory, and image data in the non-rotation direction or rotation direction stored in the image memory by the third storage means Second reading means for reading, and image forming means for forming an image on an image forming medium using image data in the non-rotating direction or rotating direction read by the second reading means, Storing the image data in the image memory by the storage means, and reading the image data stored in the image memory in the non-rotating direction by the first reading means, the reading address by the first reading means being the first address The image data stored in the image memory is read out in the non-rotating direction by the first reading means, controlled simultaneously to be less than the storage address by the storage means. After being encoded by the encoding means are adapted to encode the encoding means reads out the rotational direction of the image data stored in the image memory by the first reading means.
[0020]
An image forming apparatus according to the present invention includes a reading unit that reads image data of a document, a first storage unit that stores image data read by the reading unit in an image memory that stores image data for one page, and the first storage unit. First reading means for reading the image data stored in the image memory by the storage means, encoding means for encoding the image data read by the first reading means, code encoded by the encoding means Second storage means for storing data in a code memory for storing code data for a plurality of pages, decoding means for decoding code data stored in the code memory by the second storage means into image data, and decoding The third storage means for dividing the image data decoded by the converting means and storing it in the image memory, and the image data divided and stored in the image memory by the third storage means Second image reading means for selectively reading in the non-rotating direction or rotating direction, and image formation on the image forming medium using image data in the non-rotating direction or rotating direction read by the second reading means. An image forming unit configured to perform the storage of the decoded image data in one divided region of the image memory by the third storage unit and the image stored in the other divided region of the image memory by the second reading unit Data is read in the rotation direction at the same time.
[0021]
An image forming apparatus according to the present invention includes a reading unit that reads image data of a document, a first storage unit that stores image data read by the reading unit in an image memory that stores image data for one page, and the first storage unit. First reading means for reading the image data stored in the image memory by the storage means into a plurality of areas, and encoding the image data divided into the plurality of areas read by the first reading means, respectively. Encoding means, a second storage means for storing code data corresponding to a plurality of regions encoded by the encoding means in a code memory for storing a plurality of pages of code data, and the second storage means Decoding means for decoding code data corresponding to a plurality of areas stored in the code memory into image data, and image data corresponding to the plurality of areas decoded by the decoding means Third storage means for dividing and storing the image data in the image memory, and image data corresponding to a plurality of areas divided and stored in the image memory by the third storage means are selectively read in the non-rotation direction or the rotation direction. A second reading means for outputting, and an image forming means for forming an image on the image forming medium using image data in the non-rotating direction or the rotating direction read by the second reading means. The divided storage of the decoded image data corresponding to one area to the image memory by the storage means and the reading in the rotation direction of the image data corresponding to the other area stored in the image memory by the second reading means. At the same time.
[0022]
The image forming apparatus of the present invention reads a bit image image from a document, stores the read bit image image in an image area for one page of a page memory, and compresses the bit image image stored in the image area. Store in the code area of the page memory, decompress the compressed image stored in this code area into a bit image image, store it in the image area, and use the bit image image stored in this image area to create an image on the image forming medium. When the bit image image stored in the image area is compressed and stored in the code area of the page memory, the bit image image stored in the image area is read and compressed without being rotated. And store it in the code area of the page memory and rotate and read out the bit image stored in the image area, Storage means for compressing and storing it in another area of the code area of the page memory, reading means for selectively reading out a non-rotated compressed image or a rotated compressed image stored in the code area by this storage means, The non-rotated compressed image read by the reading means or the rotated compressed image is expanded into a bit image image and stored in the image area, and the image forming medium is stored using the bit image image stored in the image area. It is composed of image forming means for forming an image thereon.
[0023]
The image forming apparatus of the present invention reads a bit image image from a document, stores the read bit image image in an image area for one page of a page memory, and compresses the bit image image stored in the image area. Store in the code area of the page memory, decompress the compressed image stored in this code area into a bit image image, store it in the image area, and use the bit image image stored in this image area to create an image on the image forming medium. In the formation, the compressed image stored in the code area is expanded into a bit image image and stored in a part of the image area, and the compressed image stored in a part of the image area is expanded. The bit image is read in the rotation direction at the same time, and the image forming medium is read using the read rotated bit image. And performs an image formation thereon.
[0024]
The image forming apparatus of the present invention reads a bit image image from a document, stores the read bit image image in an image area for one page of a page memory, and compresses the bit image image stored in the image area. Store in the code area of the page memory, decompress the compressed image stored in this code area into a bit image image, store it in the image area, and use the bit image image stored in this image area to create an image on the image forming medium. When the bit image image stored in the image area is compressed and stored in the code area of the page memory, the bit image is divided into a part of the image area and a part of the outside of the part area. A first storage means for compressing the image and storing it in the code area of the page memory as two compressed images; one of the images stored in the code area A second storage means for expanding the compressed image and the other compressed image into a bit image image and storing them in a part of the image area and outside the part of the image area; Rotation of the decompressed bit image image stored outside or part of the image area when storing the bit image image outside the part area or part of the area The reading unit is configured to simultaneously read in the direction, and the image forming unit that forms an image on the image forming medium using the rotated bit image read by the reading unit.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0026]
That is, an embodiment of a composite type image forming apparatus having three functions of copy (PPC), facsimile (FAX) and printer (PRT) will be described.
[0027]
FIG. 1 is a schematic block diagram showing the internal structure of a digital copying machine as an example of the image forming apparatus of the present invention.
[0028]
As shown in FIG. 1, the digital copying machine includes an apparatus main body 110. In the apparatus main body 110, a scanner 13 that functions as a reading unit, which will be described later, and a printer 15 that functions as an image forming unit are provided.
[0029]
On the upper surface of the apparatus main body 110, a document placing table 112 made of transparent glass on which a reading object, that is, a document D is placed, is provided. An automatic document feeder 107 (hereinafter referred to as “ADF”) for automatically feeding a document onto a document table 112 is disposed on the upper surface of the apparatus main body 110. The ADF 107 is disposed so as to be openable and closable with respect to the document placing table 112, and also functions as a document presser that brings the document D placed on the document placing table 112 into close contact with the document placing table 112.
[0030]
The ADF 107 includes a document tray 108 on which a document D is set, an empty sensor 109 that detects the presence or absence of a document, a pickup roller 114 that picks up a document from the document tray 108 one by one, a paper feed roller 115 that transports the retrieved document, a document A pair of aligning rollers 116 for aligning the leading ends of the paper and a conveying belt 118 disposed so as to cover almost the entire document placing table 112. A plurality of originals set on the original tray 108 are taken out from the bottom page, that is, the last page in order, aligned by the aligning roller pair 116, and then placed on the original by the conveying belt 118. It is conveyed to a predetermined position on the mounting table 112.
[0031]
In the ADF 7, a reverse roller 120, a non-reverse sensor 121, a flapper 122, and a paper discharge roller 123 are disposed at the end opposite to the aligning roller pair 116 with the conveyance belt 118 interposed therebetween. A document D whose image information has been read by a scanner 13 to be described later is sent out from the document placing table 112 by a conveyor belt 118, and a document discharge unit on the upper surface of the ADF 7 via a reverse roller 120, a flapper 121, and a discharge roller 122. 124 is discharged. When reading the back side of the document D, the document D transported by the transport belt 118 by switching the flapper 122 is reversed by the reversing roller 120, and then again moved to a predetermined position on the document placement table 112 by the transport belt 118. Sent.
[0032]
The scanner 13 disposed in the apparatus main body 110 has an exposure lamp 125 as a light source for illuminating the document D placed on the document table 112 and a first light that deflects reflected light from the document D in a predetermined direction. The exposure lamp 125 and the first mirror 126 are attached to a first carriage 127 disposed below the document table 112.
[0033]
The first carriage 127 is disposed so as to be movable in parallel with the document placing table 112 and is reciprocated below the document placing table 112 by a drive motor via a toothed belt (not shown).
[0034]
A second carriage 128 that is movable in parallel with the document placing table 112 is disposed below the document placing table 112. Second and third mirrors 130 and 131 that sequentially deflect the reflected light from the document D deflected by the first mirror 126 are attached to the second carriage 128 at right angles to each other. The second carriage 128 is driven with respect to the first carriage 127 by a toothed belt or the like that drives the first carriage 127, and the document is placed on the first carriage at half the speed. It is moved in parallel along the table 112.
[0035]
Further, below the document table 112, the imaging lens 132 that focuses the reflected light from the third mirror 131 on the second carriage 128 and the reflected light that is focused by the imaging lens 132 are received. A CCD sensor 134 for photoelectric conversion is disposed. The imaging lens 132 is movably disposed in a plane including the optical axis of the light deflected by the third mirror 131 via a drive mechanism, and moves itself to reflect light at a desired magnification. Form an image. The CCD sensor 134 photoelectrically converts the incident reflected light and outputs an electrical signal corresponding to the read document D.
[0036]
On the other hand, the printer 15 includes a laser exposure device 140 that functions as a latent image forming unit. The laser exposure device 140 rotates a semiconductor laser 141 as a light source, a polygon mirror 136 as a scanning member that continuously deflects the laser light emitted from the semiconductor laser 141, and a polygon mirror 136 at a predetermined rotational speed described later. As a scanning motor to be driven, a polygon motor 137 and an optical system 142 for deflecting laser light from the polygon mirror and guiding it to a photosensitive drum 144 described later are provided. The laser exposure apparatus 140 having such a configuration is fixedly supported on a support frame (not shown) of the apparatus main body 110.
[0037]
The semiconductor laser 141 is on / off controlled in accordance with the image information of the document D read by the scanner 13 or the facsimile transmission / reception document information. This laser light is passed through the polygon mirror 136 and the optical system 142 to the photosensitive drum 144. The electrostatic latent image is formed on the circumferential surface of the photosensitive drum 144 by scanning the circumferential surface of the photosensitive drum 144.
[0038]
Further, the printer 15 has a rotatable photosensitive drum 144 as an image carrier disposed almost at the center of the apparatus main body 110, and the peripheral surface of the photosensitive drum 144 is irradiated with laser light from the laser exposure device 140. Exposure is performed to form a desired electrostatic latent image. Around the photosensitive drum 144, a charging charger 145 for charging the drum peripheral surface to a predetermined charge, and toner as a developer is supplied to the electrostatic latent image formed on the peripheral surface of the photosensitive drum 144 to obtain a desired charge. A developing unit 146 that develops at an image density, a transfer material fed from a paper cassette described later, that is, a peeling charger 147 for separating the copy paper P from the photosensitive drum 144 are integrally provided. A transfer charger 148 for transferring the toner image formed on the paper P to the paper P, a peeling claw 149 for peeling the copy paper P from the circumferential surface of the photosensitive drum 144, a cleaning device 150 for cleaning the toner remaining on the circumferential surface of the photosensitive drum 144, In addition, a static eliminator 151 for neutralizing the circumferential surface of the photosensitive drum 144 is disposed in order.
[0039]
In the lower part of the apparatus main body 110, an upper cassette 152, a middle cassette 153, and a lower cassette 154 that can be pulled out from the apparatus main body are arranged in a stacked state, and copy papers of different sizes are loaded in each cassette. Yes. A large-capacity feeder 155 is provided on the side of these cassettes. The large-capacity feeder 155 stores about 3000 sheets of frequently used copy paper P, for example, A4 size copy paper P. . A paper feed cassette 157 that also serves as a manual feed tray 156 is detachably mounted above the large capacity feeder 155.
[0040]
In the apparatus main body 110, a conveyance path 158 extending from each cassette and the large-capacity feeder 155 through a transfer portion located between the photosensitive drum 144 and the transfer charger 148 is formed, and a fixing path is formed at the end of the conveyance path 158. A fixing device 160 having a lamp 160a is provided. A discharge port 161 is formed in the side wall of the apparatus main body 110 facing the fixing device 160, and a single tray finisher 180 is attached to the discharge port 161.
[0041]
In the vicinity of the upper cassette 152, the middle cassette 153, the lower cassette 154, the paper feed cassette 157, and the vicinity of the large capacity feeder 155, pickup rollers 163 for taking out the sheets P one by one from the cassette or the large capacity feeder are provided. . The transport path 158 is provided with a number of paper feed roller pairs 164 that transport the copy paper P taken out by the pickup roller 163 through the transport path 158.
[0042]
A registration roller pair 165 is provided on the upstream side of the photosensitive drum 144 in the conveyance path 158. The registration roller pair 165 corrects the inclination of the taken copy paper P, aligns the leading edge of the toner image on the photosensitive drum 144 and the leading edge of the copy paper P, and determines the moving speed of the peripheral surface of the photosensitive drum 144. The copy paper P is fed to the transfer unit at the same speed. A pre-aligning sensor 166 for detecting the arrival of the copy paper P is provided in front of the registration roller pair 165, that is, on the paper feed roller 164 side.
[0043]
The copy paper P picked up one by one from each cassette or large-capacity feeder 155 by the pickup roller 163 is sent to the registration roller pair 165 by the paper feed roller pair 164. The copy paper P is fed to the transfer section after the leading edge is aligned by the registration roller pair 165.
[0044]
In the transfer portion, the developer image formed on the photosensitive drum 144, that is, the toner image is transferred onto the paper P by the transfer charger 148. The copy sheet P to which the toner image has been transferred is peeled from the peripheral surface of the photosensitive drum 144 by the action of the peeling charger 147 and the peeling claw 149, and is transferred to the fixing device 160 via the conveyance belt 167 constituting a part of the conveyance path 52. Be transported. Then, after the developer image is melted and fixed on the copy paper P by the fixing device 160, the copy paper P is discharged onto the finisher 180 through the discharge port 161 by the paper feed roller pair 168 and the paper discharge roller pair 169.
[0045]
Below the conveyance path 158, an automatic double-side device 170 that reverses the copy paper P that has passed through the fixing device 160 and sends it again to the registration roller pair 165 is provided. The automatic double-side device 170 includes a temporary stacking unit 171 that temporarily stacks the copy paper P, and a reverse path 172 that branches from the conveyance path 158 and reverses the copy paper P that has passed through the fixing device 160 and guides it to the temporary stacking unit 71. And a pick-up roller 173 that picks up the copy paper P collected in the temporary stacking unit one by one, and a paper feed roller 175 that feeds the picked-up paper to the registration roller pair 165 through the transport path 174. In addition, a branching gate 176 that selectively distributes the copy paper P to the discharge port 161 or the reversing path 172 is provided at a branch portion between the transport path 158 and the reversing path 172.
[0046]
When performing double-sided copying, the copy paper P that has passed through the fixing device 160 is guided to the reversing path 172 by the sorting gate 176 and temporarily accumulated in the temporary accumulating unit 171 in an inverted state, and then the pickup roller 173 and The paper is fed to the registration roller pair 165 through the conveyance path 174 by the paper feed roller pair 175. Then, after the copy paper P is aligned by the registration roller pair 165, it is sent again to the transfer unit, and the toner image is transferred to the back surface of the copy paper P. Thereafter, the copy paper P is discharged to the finisher 180 via the conveyance path 158, the fixing device 160 and the paper discharge roller 169.
[0047]
The finisher 180 staples and stores the ejected partially structured document in units. Each time the copy paper P to be stapled is discharged from the single sheet discharge port 161, the guide bar 181 moves toward the staple side and aligns. When all the paper has been discharged, the paper presser arm 152 suppresses a partial unit of the copy paper P, and the stapler unit 183 performs stapling. After that, the guide bar 181 is lowered, and the copy paper P for which stapling is finished is discharged to the finisher discharge tray 184 by the finisher discharge roller 185 in a part of the copy paper P. The lowering amount of the finisher discharge tray 184 is determined to some extent by the number of copy sheets P to be discharged, and decreases step by step every time it is discharged in some units. Further, the guide bar 181 for aligning the discharged copy paper P is at a height such that it does not hit the already stapled copy paper P placed on the finisher discharge tray 184.
[0048]
Further, the finisher discharge tray 184 is connected to a shift mechanism (not shown) that shifts partly (for example, in the four directions of front, rear, left, and right) in the sort mode.
[0049]
FIG. 2 is a block diagram showing the overall configuration of the image forming apparatus. This apparatus stores a basic unit 1 that executes a basic copying function, temporarily stores image data when the apparatus is connected to another system, and the like. A system basic unit 2 having a page memory for storing image data when the image data is edited, processed and copied, and an optical disk for electronically and semi-permanently storing the image data input from the basic unit 1 System expansion unit 3 having a device and the like and having control means for converting image data and control data into a control system and image format of other systems when image data or control data is exchanged with other systems It consists of three systems.
[0050]
The basic unit 1 and the system basic unit 2 are connected by a basic part system interface 4 for exchanging control data and a basic part image interface 5 for exchanging image data.
[0051]
The system basic unit 2 and the system expansion unit 3 are connected by an expansion unit system interface 6 for exchanging control data and an expansion unit image interface 7 for exchanging image data.
[0052]
That is, the basic unit 1 and the system expansion unit 3 are not directly connected, and control data and image data are always exchanged via the system basic unit 2.
[0053]
This image forming apparatus can take three forms depending on whether or not the system basic unit 2 and the system expansion unit 3 are connected.
[0054]
That is, the first form is a configuration of only the basic unit 1, and the basic function in this configuration is a copying function, and copying processing with simple editing processing such as enlargement / reduction processing and masking / trimming processing is possible. is there.
[0055]
The second form is a form in which the system basic unit 2 is connected to the basic unit 1. In this form, in addition to the copying function in the basic unit 1, a page memory that temporarily stores image data is used to rotate the image. Editing processing, such as processing and composition processing of a plurality of images, becomes possible. In addition to the system expansion unit 3, the system basic unit 2 includes a FAX (facsimile) unit 8 constituting a communication line control means such as a facsimile and a printer of the basic unit 1 as a remote printer of a control device such as an external personal computer. It is possible to connect a printer controller 9 for use as a printer, and an image can be transmitted from the FAX unit 8 to another system or device via a communication line, or vice versa. Image data can be received from the system or equipment, and the received image data is sent to the basic unit 1 and printed out by a printer described later.
[0056]
The third form is a form in which the basic unit 1, the system basic unit 2, and the system expansion unit 3 are connected, as shown in FIG.
[0057]
In this embodiment, in addition to the functions of the first and second embodiments, image data is stored electronically and semi-permanently, and a data storage / management function for managing the stored image data, a local area network (LAN) to be described later Image data transmission / reception function and general-purpose interface that transmits images from the line control means to other systems and devices via the LAN line, and conversely receives image data from other systems and devices via the LAN line A printer function for converting the print control code sent from the personal computer into image data through the page memory of the system basic unit 2 and printing out the image data from the printer of the basic unit 1 becomes possible.
[0058]
As shown in FIG. 3, the basic unit 1 includes a system CPU 11 constituting a control unit main body, a control panel 12 having an operation unit and a display unit, an image scanner 13 as input means for reading an image from a document, and an image processing circuit. 14 and a printer 15 as output means. The system CPU 11 is connected to a control panel 12, a scanner 13, an image processing circuit 14, and a printer 15 as an output unit for performing image formation output via a basic system bus 16, and controls these. The basic part system bus 16 is connected to the basic part system interface 4.
[0059]
The scanner 13 has a CCD line sensor (not shown) composed of a plurality of (one line) light receiving elements arranged in a line, and an image of a document placed on a document table (not shown) is displayed on the system CPU 11. Is read line by line in accordance with an instruction from the image data, and after the image is converted into 8-bit digital data, it is output to the image processing circuit 14 as time-series digital data together with a synchronization signal via the scanner interface.
[0060]
The printer 15 is composed of a laser optical system (not shown) and an image forming unit (not shown) that combines an electrophotographic system capable of forming an image on a transfer sheet, and an image processing circuit 14 according to an instruction from the system CPU 11. 4 bits of digital image data are input in synchronization with a synchronization signal via a printer interface, and electrostatic latent images are transferred onto a photosensitive drum (not shown) by a laser beam having a pulse width corresponding to the size of the image data. After the image is formed, the electrostatic latent image is visualized by a visualizing means (not shown), the image visualized by a transfer means (not shown) is transferred to transfer paper, and the fixing means (not shown) is used. The image on the transfer paper is fixed and the transfer paper is output.
[0061]
The control panel 12 includes an operation unit for setting the operation mode and parameters of the apparatus and a display unit for displaying a system state or an image image stored in the page memory of the system basic unit 2.
[0062]
The system CPU 11 also controls each part of the system basic unit 2 described later.
[0063]
As shown in FIG. 6, the image processing circuit 14 includes a smoothing edge emphasizing circuit 14a, an editing / moving circuit 14b, an enlarging / reducing circuit 14c, and a gradation converting circuit 14d.
[0064]
The smoothing edge emphasizing circuit 14a removes noise mixed at the time of image reading by the smoothing circuit, and sharpens an edge that is blurred by the smoothing by the edge emphasizing circuit.
[0065]
The editing / moving circuit 14b is a block that performs simple editing processing in units of lines, and performs, for example, moving processing in the line direction and masking / trimming processing.
[0066]
The enlargement / reduction circuit 14c performs enlargement / reduction processing by repeating a pixel according to a designated scaling factor or by combining thinning-out processing and interpolation processing.
[0067]
The gradation conversion circuit 14d converts the gradation of the 1-pixel 8-bit image data read by the scanner 13 to the designated gradation number using the area gradation method. The tone-converted image data is sent to the system basic unit 2 via the printer 15 or the scanner data bus 17 and the basic image interface 5 as 1-pixel 4-bit image data which is the number of bits of the printer.
[0068]
The correction of the nonlinearity of the input / output characteristics of the printer 15 is performed simultaneously with the gradation processing using the area gradation method.
[0069]
As shown in FIG. 4, the system basic unit 2 includes a page memory 28 for storing bit image data read by the scanner 13 as image data, encoded data obtained by compressing the image data, and a system CPU 11 in the basic unit 1. Controls the communication of control information with the CPU in the system expansion unit 3 and controls the access to the page memory 28 from the basic unit 1 and the system expansion unit 3 and generates the addresses of the page memory 28 The page memory address control circuit 26, the image bus 29 for transferring data between the devices in the system basic unit 2, and the data transfer for transferring data between the page memory 28 and other devices via the image bus 29. Page memory data control circuit 27 for controlling Only to have.
[0070]
The page memory 28 includes an image area (work area, image memory) 28a for storing image data for one page and a code area (file area) 28b for storing compressed encoded data for a plurality of pages. ing.
[0071]
In addition, the image data I / F 210 that interfaces image data when transferring image data to and from the basic unit 1 via the basic image interface 5, and the image data when other image data is transmitted to devices having different resolutions. A resolution conversion binary rotation circuit 212 that converts image data received from devices with different resolutions to the resolution of the printer 15 of the basic unit 1, and performs 90-degree rotation processing of binary image data. Compressed image data sent for devices that store image data, such as facsimile transmission or optical disk storage, compresses input image data, or visualizes compressed image data via the printer 15 Therefore, a compression / decompression circuit 211 is provided for decompression.
[0072]
Also, a FONT memory that stores character fonts, a work memory that temporarily stores control information used by the system CPU 11, and a program memory that stores processing programs when processing is performed using the system basic unit 2 The system memory (ROM / RAM) 24 composed of, for example, the system DMA controller 23 for performing high-speed data transfer between devices of the basic system bus 16, the control information between the printer controller 9 and the system CPU 11 A printer controller interface 213 is provided for interfacing the control information and image data when exchanging or transferring image data between the printer controller 9 and the image bus 29.
[0073]
Further, it is connected to the system control circuit 21 and is connected to the communication memory 25 and the image data I / F 210 for storing the control information when communicating the control information between the system CPU 11 and the CPU of the system expansion unit 3. A multi-value rotation memory 214 is provided that is used when the image data is output by being rotated 90 degrees or 180 degrees when the image data is output from the printer 15.
[0074]
The FAX unit 8 and the printer controller 9 are connected as an option.
[0075]
As shown in FIG. 5, the system expansion unit 3 includes an expansion CPU 31 that controls each internal device via an expansion unit system bus 43, an expansion DMA controller 32 that controls data transfer on the expansion unit system bus 43, A general-purpose ISA bus 44; an ISA bus controller 33 that interfaces the expansion unit system bus 43 and the ISA bus 44; storage means connected to the expansion unit system bus 43 for electronically storing image data, such as a hard disk device 35; A hard disk interface 34 as an interface, storage means connected to the ISA bus 44 for electronically storing image data, for example, an optical disk device 38, an optical disk interface 37 as an interface thereof, and a local area for realizing a LAN function Ne A network line control device (LAN) 41, a printer controller control device 40 for realizing a printer function, a G4 / FAX control circuit 39 having a G4 / FAX control function, and an extended SCSI interface used when connecting a SCSI specification device. 42, an expansion unit image bus 45 for outputting image data from the printer controller control device 40 to the system basic unit 2 via the expansion image interface 7, and the expansion unit system bus 43 and the expansion unit image bus 45. It comprises a buffer memory 36 that provides an interface when data is exchanged between them.
[0076]
The optical disk interface 37, the optical disk device 38, the G4 / FAX control circuit 39, the printer controller control device 40, the local area network line control device 41, and the extended SCSI interface 42 are optional and can be detached from the system expansion unit 3. It has become.
[0077]
The optical disk device 38 is connected to the ISA bus 44 via the interface 37, and the expansion CPU 31 uses the SCSI command to connect the optical disk device 38 via the expansion system bus 43, the ISA bus controller 33, and the ISA bus 44. Control.
[0078]
The local area network line control device 41 is a line control unit that controls communication of control data and image data with other devices on the network based on the protocol of the connected network system, and communication control data and image data from the LAN. Or a shared memory for temporarily storing control data and image data from the system expansion bus and a system expansion bus interface.
[0079]
The printer controller controller 40 is a Centronics-compliant parallel interface for exchanging control codes and image data with a personal computer, and a system expansion unit image bus for transferring bit image data to the page memory 28 of the system basic unit. 45, a system expansion image bus interface that interfaces with 45, an image data transfer control unit that controls the transfer of image data in the apparatus, and interprets control codes from a personal computer, via an expansion unit system bus 43 and an ISA bus 44 Control information to the extended CPU 31, interpretation of a print control code from a personal computer, conversion into bit information, and then storing the bit information in a memory in the apparatus, an interface with the ISA bus 44 Composed of a system expansion bus interface to take the scan.
[0080]
Next, details of the configuration and functions of the main part in the system basic unit 2 will be described.
[0081]
As shown in FIG. 7, the system control circuit 21 includes a communication memory access control circuit 401 that controls communication of control information between the system CPU 11 and the extended CPU 31, a communication memory interface 402 that interfaces with the communication memory 25, Control information and image information sent from the system CPU 11 of the basic unit 1 via the page memory access control circuit 403 that controls access to the page memory 28 from the basic unit 1 and the system expansion unit 3, and the basic system bus 16. Control information and image information from the basic system bus interface 405 and the system expansion unit 3 that decode the address sent simultaneously and distribute the control information or image information to the blocks in the corresponding system basic unit 2 A system expansion bus interface 406 that decodes addresses sent simultaneously and distributes them to the corresponding blocks in the circuit, means capable of page memory access on the basic system bus 16 (CPU 11 and DMA controller 22 in the basic unit), When page memory access means on the system expansion bus 43 (CPU 31 and DMA controller 32 of the system expansion unit 3) accesses image data in the page memory 28 via each system bus, the page memory access is performed. The page memory interface 404 is used to interface the exchange of image data between the control circuit 403 and the page memory 28.
[0082]
When the CPU 11 of the basic unit 1 and the CPU 31 of the system expansion unit 3 exchange control codes with the communication memory 25 via the communication memory interface 402 in the system control circuit 21, the communication memory access control circuit 401 receives the communication memory 25. Control access.
[0083]
The communication memory 25 is mapped to the memory space of the CPU 11 of the basic unit 1 and the CPU 31 of the system expansion unit, and from each of them, data can be read from and written to the communication memory 25 by accessing a specific area. Become.
[0084]
As shown in FIG. 8, the communication memory access control circuit 401 includes an arbitration circuit 410, a communication memory access sequencer 412, a bidirectional selector 413, and an interrupt control circuit 414.
[0085]
The arbitration circuit 410 controls communication memory access priority between the CPU 11 of the basic unit 1 and the CPU 31 of the system expansion unit 3. When the CPU 11 of the basic unit 1 and the CPU 31 of the system expansion unit 3 simultaneously access the communication memory 25, one of the access is permitted based on the set priority, and the other access is waited.
[0086]
The communication memory access sequencer 412 outputs a read or write control signal to the communication memory 25 based on the permitted CPU request.
[0087]
Based on the arbitration result of the arbitration circuit 410, the bidirectional selector 413 outputs the address for the communication memory 25 output by the permitted control means to the communication memory 25 in synchronization with the timing signal output by the communication memory access sequencer 412. . In the write operation, the communication information (data) output together with the address by the authorized CPU is output to the communication memory 25 together with the address information. Further, in the read operation, the communication information read from the communication memory 25 is input by the address from the permitted CPU to the communication memory 25 and the timing signal output from the communication memory access sequencer 412 and output to the permitted CPU. To do.
[0088]
The page memory access control circuit 403 includes an arbitration circuit 430, data registers 431, 432, 436, and 437, an address register 433, a bidirectional select 434, and a page memory access sequencer 435, as shown in FIG.
[0089]
The arbitration circuit 430 controls the priority of page memory access by the CPU 11 of the basic unit 1 and the CPU 31 of the system expansion unit 3. When the CPU 11 and the CPU 31 access the page memory 28 at the same time, access of one of the CPUs is permitted based on the set priority, and the access of the other CPU is made to wait.
[0090]
The page memory access sequencer 435 outputs a read or write control signal to the page memory 28 to the address control circuit 26 based on the permitted CPU request.
[0091]
The bidirectional selector 434 outputs the address for the page memory 28 output by the authorized CPU to the address control circuit 26 in synchronization with the timing signal output by the page memory access sequencer 435 based on the arbitration result of the arbitration circuit 430. . In the write operation, information (data) output together with the address by the authorized CPU is output to the data control circuit 27 together with the address information. Also, in the read operation, the address to the page memory 28 from the authorized CPU and the image data read from the page memory 28 by the timing signal output from the page memory access sequencer 435 are input via the data control circuit 27, Output to the authorized CPU.
[0092]
The data register 431 and the data register 432 are registers that temporarily store data when the basic unit 1 accesses the page memory 28, and the address register 433 temporarily stores the address of the page memory 28 output by the basic unit 1. This register is stored in
[0093]
Here, when the basic unit 1 accesses the page memory 28 using the data register 431, the address output by the basic unit 1 is temporarily stored in the address register 433, and the page memory is accessed via the address control circuit 26. 28. On the other hand, when the basic unit 1 accesses the page memory using the data register 432, the address output by the basic unit 1 is ignored, and the address generation unit of the address control circuit 26 sets the address based on the setting information. Output to the memory 28.
[0094]
The data register 436 and the data register 437 are registers that temporarily store data when the system expansion unit 3 accesses the page memory 28, and two registers when the system expansion unit 3 accesses the page memory 28. The address generator of the common address control circuit 26 outputs an address to the page memory 28 based on the setting information.
[0095]
The system DMA controller 23 of the basic unit 1 is a controller for transferring data between devices on the basic system bus 22 at high speed in terms of hardware without using the CPU 11 of the basic unit 1.
[0096]
Data transfer using the system DMA controller 23 includes transfer of compressed data (code data) between the page memory 28 and the FAX unit 8 in the FAX transmission / reception process, and an image on the page memory 28 to the control panel 12. There are image data transfer between the page memory 28 for display and the control panel 12, data transfer between the system memory 24 for displaying the operation screen on the control panel 12, and the control panel 12.
[0097]
The address control circuit 26 for generating the address of the page memory 28, as shown in FIG. 10, transfers a transfer control sequencer 610 that executes various transfer sequences according to requests from the image bus, requests for the image bus, and requests for the system bus. An arbitration unit 611 that performs arbitration, an address generation unit 612 that generates various memory addresses of a plurality of channels in transfer from the image bus, a selector 613 that switches an address output from the address generation unit 612 and a system address, a DRAM address, The DRAM control unit 614 generates a control signal.
[0098]
The address control circuit 26 receives a memory access request from the two systems of the image bus and the system bus. This request is arbitrated by the arbitration unit 611, and data transfer processing on the side that has won the arbitration is performed.
[0099]
When the request on the system bus side wins arbitration, the system address selected by the selector 613 is input to the DRAM control unit 614. The DRAM controller 614 converts the input address into a DRAM address and generates control signals necessary for reading and writing.
[0100]
The transfer control sequencer 610 receives an address channel signal together with a request from the image bus, and selects one from a plurality of address generators in the address generator 612. When the request on the image bus side wins arbitration, the memory address of the selected channel is output from the address generation unit 612 and input to the DRAM control unit 614.
[0101]
As shown in FIG. 11, the address generator 612 receives four-channel two-dimensional address generators 631, 632, 633, and 634, two-channel FIFO address generators 635 and 636, and a channel select signal from a transfer sequencer. The selector 637 selects one of the generated memory addresses.
[0102]
Each of the two-dimensional address generators 631 to 634 can generate various addresses. For example, as shown in FIG. 12A, it is possible to sequentially generate addresses in the X direction in synchronization with the clock from the transfer control sequencer. Further, by changing the parameters, as shown in FIG. 12B, it is also possible to sequentially generate addresses in the reverse direction of the Y direction.
[0103]
Furthermore, the start address and the main scanning width (XW) of one line can be arbitrarily set according to the paper size of the document.
[0104]
By using such a two-dimensional address generator capable of generating various addresses, transfer, rotation reading and repeated reading to an arbitrary rectangular area of the page memory 28, and two channels of the two-dimensional address generator are used. As a result, image editing such as movement, rotation, vertical / horizontal conversion, repetition, mirror image, and the like between arbitrary regions of the page memory 28 is possible.
[0105]
The FIFO address generators 635 and 636 generate a FIFO address for using the page memory 28 as a FIFO memory and a status necessary for FIFO control.
[0106]
Status includes FIFO full (FIFO area is full of unread data), FIFO empty (FIFO area has no unread data), FIFO half (FIFO area has more than half unread data) ) Further, by reading the FIFO register from the system CPU 11, it is possible to know the amount of data and the free capacity in the FIFO.
[0107]
By performing FIFO control using these statuses, when transferring from the device of the image bus 29 to the device or from the device of the image bus 29 to the system bus 22, the transfer speed and the difference in transfer timing can be determined in the FIFO. It can be absorbed by the memory, and high-speed data transfer is possible.
[0108]
The FIFO address generators 635 and 636 can be used as a one-dimensional address generator for two channels per channel when the FIFO control is not performed.
[0109]
The detailed configuration of the FIFO address generators 635 and 636 will be described with reference to FIG. The FIFO address generator includes a one-dimensional address generator channel A4601 and a channel B4603, start address setting units A4602 and B4604 that give start addresses to the respective one-dimensional address generators, a FIFO status generator 4605, and a FIFO area size setting unit. 4606.
[0110]
The one-dimensional address generator 4601 is counted up by the count up signal every time one transfer is completed. Therefore, data can be written to or read from consecutive addresses in the memory.
[0111]
In addition, the address generator 635, 635 generates a continuous one-dimensional address, and when the address reaches the size of the FIFO area from the start address, generates a loop address where the address returns to the start address in the next transfer. There are two modes of FIFO address mode.
[0112]
In the FIFO address mode, a write address for FIFO control is generated in one channel, and an address for FIFO control is generated in the other channel.
[0113]
The FIFO status generator generates a status indicating the data state of the FIFO area from the addresses of the two channels and the size of the FIFO area.
[0114]
There are two statuses, FIFO full and FIFO empty.
[0115]
FIFO full indicates a state in which unread data is full in the FIFO area, and data cannot be written any more. Therefore, data writing is prohibited by using this FIFO full signal.
[0116]
The FIFO empty indicates that there is no unread data in the FIFO area, and no more data can be read out. Therefore, reading of data is prohibited by using this FIFO empty signal.
[0117]
By performing transfer control using the FIFO address mode in this way, a part of the memory is used as the FIFO area, and high-speed data transfer can be performed by absorbing the difference in writing and reading speed.
[0118]
FIG. 14 is a conceptual diagram when two-dimensional access is made to the page memory 28 (the image area 28a thereof).
[0119]
Assuming that one access width (64 bits in the figure) of the page memory 28 is one column, one line is constituted by an integral multiple of one column. In the same line, columns that are continuous in the X direction have continuous linear addresses in the page memory 28, and the linear addresses of the last column of the line and the first column of the next line are continuous.
[0120]
FIG. 15 shows the two-dimensional memory of the page memory 28 of FIG. 14 written in linear addresses.
[0121]
As shown in FIG. 16, the data control circuit 27 controls data transfer between devices on the image bus 29 in the system basic unit 2 and data transfer between the devices on the image bus 29 and the page memory 28. A data transfer control unit 701, an image processing unit 702 that executes bit block transfer and various raster operations (logical operations), a CPU 11 of the basic unit 1, or a CPU 31 of the system expansion unit 3 are connected to the page memory 28 via the system control circuit 21. System interface 703 for interfacing data when accessing (reading / writing) data, and in the write processing to the page memory 28, based on the page memory access arbitration result of the address control circuit 26, via the image data transfer control unit 701 Sent Selector 704 for selecting whether data is coming from a device on the image bus 29 or data sent from the CPU (CPU 11 of the basic unit 1 or CPU 31 of the system expansion unit 3) sent via the system interface 703, page memory 28, data is sent to a device on the image bus 29 via the image data transfer control unit 701 based on the page memory access arbitration result of the address control circuit 26 in the process of reading data from 28, or via the system interface 703. The selector 705 selects whether to send data to the CPU (the CPU 11 of the basic unit 1 or the CPU 31 of the system expansion unit 3).
[0122]
Next, the control of the image data transfer control unit 701 shown in FIG. 16 will be described. There are the following two forms of image data transfer controlled by the image data transfer control unit 701.
[0123]
One form is data transfer between I / O devices on the image bus 29 of the system basic unit 2, and both the source (transfer source) and the destination (transfer destination) are also on the image bus 29, and image data transfer control from the source. This is composed of two cycles, a read cycle for fetching data into the data buffer in the unit 701 and a write cycle for writing data on the data buffer to the destination.
[0124]
Another form is data transfer between the I / O device on the image bus 29 of the system basic unit 2 and the page memory 28, and a data transfer cycle between the I / O device and the data buffer in the image data transfer control unit 701. , And consists of two cycles of data transfer between the data buffer and the page memory 28.
[0125]
Since the page memory 28 and the data buffer are independent of the image bus 29, the two cycles can operate in parallel.
[0126]
Further, the image data transfer control unit 701 can designate 8 channels of the above-described two forms of data transfer, and can simultaneously transfer 8 channels of data.
[0127]
As shown in FIG. 17, the image data transfer control unit 701 includes a data buffer 740, an image bus priority control unit 741, a transfer control sequencer 742, a page memory priority control unit 743, a page memory timing control unit 744, a terminal counter. 745, an interrupt control unit 746, a control bus interface 747, a parameter register 748, and an I / O buffer 749.
[0128]
The data buffer 740 has data registers for the number of channels for temporarily storing data from the source in data transfer.
[0129]
The image bus priority control unit 741 receives a data transfer request (REQ) from a device on the image bus 29, determines a device that permits data transfer by a predetermined priority control, and sends data to the permitted device. Notify (ACK) the start of transfer.
[0130]
The transfer control sequencer 742 generates a timing signal for data transfer between the source device and the destination device determined based on the priority control result of the image bus priority control unit 741, and outputs it to the image bus 29.
[0131]
The page memory priority control unit 743 receives a request signal output from the data buffer 740 and determines a data transfer channel between the page memory 28 and the data buffer 740 based on a predetermined priority.
[0132]
The page memory timing control unit 744 generates a timing signal for data transfer between the page memory 28 and the data buffer 740 of the transfer channel determined based on the priority control result of the page memory priority control unit 743, and generates an address control circuit 26. Output to. The transfer request signal from the data buffer 740 is transmitted from the page memory 28 when the data from the device on the image bus 29 is stored in the data buffer 740 in the write process to the page memory 28. In the read process, the data is output to the page memory priority control unit 743 when no data is stored in the data buffer 740.
[0133]
The parameter register 748 is a register for setting the transfer source, transfer destination, transfer byte count, presence / absence of interrupt processing at the end of transfer, and the like for each transfer channel.
[0134]
The image bus 29 has a 32-bit data width, and a 32-bit data transfer is always performed regardless of the bit width of one pixel. For example, when binary (1 bit / pixel) data is written from the scanner 13 to the page memory 28, 32 pixel data on the image bus 29 are paged from the image data I / F 210 via the image data transfer control unit 701 at a time. When data is transferred to the memory 28 and multilevel (4 bits / pixel) data is written to the page memory 28, data of 8 pixels is transferred on the image bus 29 at a time. The data is converted into 32 bits according to the number of bits of one pixel in each device on the image bus 29.
[0135]
Data transfer priority control on the image bus 29 gives priority to transfer requests from devices that cannot stop or wait for data transfer, such as output to the printer 15 and input processing from the scanner 13. Depending on the nature of the device, transfer requests for devices that can be allowed to wait for data transfer, such as compression / decompression processing and resolution conversion processing, are allowed only when there is no transfer request from a device with high priority. Decided to determine priority.
[0136]
Incidentally, a timer 900 is connected to the system bus 16 of FIG. As shown in FIG. 18, the timer 900 includes a timer control unit 901, a reference clock generation circuit 902, a reference clock frequency dividing circuit 903, and a down counter 904.
[0137]
The timer control unit 901 controls the division ratio setting of the reference clock frequency dividing circuit 902 and the start and stop of the down counter 904 via the system bus 16 from the system CPU 11.
[0138]
Further, the timer control unit 901 can generate an interrupt signal to the system CPU 11 by a carry-down signal output from the down counter 904.
[0139]
The reference clock generation circuit 902 generates an accurate square wave of 25 MHz by a crystal oscillator.
[0140]
The reference clock frequency dividing circuit 903 divides the reference clock to a frequency of 1 / n by an arbitrary frequency dividing ratio from 1/1 to 1/65536 according to the setting from the system CPU 11.
[0141]
The down counter 904 is a 32-bit binary down counter that counts down in synchronization with the divided clock. The initial value of the down counter 904 is set by the system CPU 11 via the system bus 16.
[0142]
Further, when a carry-down occurs (down from 0) in the down counter 904, the initial value set by the previous system CPU 11 is automatically set. The value of the down counter 904 can be read from the system CPU 11 via the system bus 16 at any time.
[0143]
The countdown start and stop of the downcounter 904 is controlled by a count enable signal output from the timer control unit 901.
[0144]
Next, a detailed configuration of the image bus priority control unit 741 in FIG. 17 will be described with reference to FIG. The image bus priority control unit 741 includes an image bus transfer request arbitration unit, 910, a request mask circuit 911 for 8 channels, and a request generation unit 912 for 8 channels.
[0145]
The request generator 912 is independent for each of the eight transfer channels. An image bus transfer request signal and a channel buffer status are input to the request generation unit 912 of each channel, and an internal valid transfer request is generated when both conditions are satisfied. Here, the image bus transfer request signal is a signal that is activated when a device connected to the image bus 29 requests data transfer on the image bus 29. The channel buffer status is a signal indicating the state of the data buffer 740 for data transfer of each transfer channel. The channel buffer status includes an “empty” state in which no valid data is contained and valid data is contained in the channel data buffer. There are two states, “full”.
[0146]
In the case of device read transfer from the device of the image bus 29 to the data buffer 740, when the buffer status of the data buffer of the channel to be transferred is “empty” and the request signal for the channel from the device is active, the request generation unit 911 An internal valid transfer request occurs.
[0147]
In the case of device write transfer from the data buffer 740 to the device on the image bus 29, there is valid data in the data buffer 740 of the channel to be transferred, the buffer status is “full”, and the request signal for the channel from the device is active. At this time, a valid internal transfer request is generated from the request generation unit 912.
[0148]
The request mask circuit 911 controls whether or not to validate the transfer request created by the request generation unit 912 in the previous stage.
[0149]
The transfer channel enable determines whether transfer of the channel is permitted or not.
[0150]
The TC mask is used to control the transfer amount. The number of words to be transferred is set in advance in the terminal counter 745. When the predetermined number of words is transferred, the TC mask becomes active and the transfer of the channel is prohibited. When this transfer amount control is not performed, the TC mask is always inactive by setting.
[0151]
The FIFO control mask controls transfer permission / prohibition of the channel when performing FIFO control, and the FIFO control mask is active when transfer is prohibited and inactive when transfer is permitted.
[0152]
Whether to perform the FIFO control based on the FIFO status from the FIFO address generators 635 and 636, the comparison result of the transfer comparator of the terminal counter 745, or not to perform the FIFO control is selected by setting from the system CPU11. When the FIFO control is not performed, the FIFO control mask is always inactive by setting.
[0153]
The image bus transfer request arbitration unit 910 arbitrates transfer requests for eight channels generated by the request mask circuit 911, selects one channel, and indicates that the request is accepted and transfer is permitted to the device of the selected channel. Outputs a bus transfer acknowledge signal. The device that has received this acknowledge signal performs data transfer on the image bus 29.
[0154]
The priority control of arbitration performed when transfer requests are generated from a plurality of channels is round robin control in which the priority of the channel that performed the previous transfer is the lowest when channels 1 to 8 are arranged in a ring shape. . Therefore, even if all 8 channels continue to issue a transfer request, the order always comes within 8 transfers, so the transfer is performed equally for each channel.
[0155]
Next, a detailed configuration of the page memory priority control unit 743 in FIG. 17 will be described with reference to FIG. The page memory priority control unit 743 includes a page memory transfer request arbitration unit 921, a request mask circuit 922 for 8 channels, and a request generation unit 923 for 8 channels.
[0156]
The request generator 923 is independent for each of the eight transfer channels. The channel buffer status is input to the request generation unit 923 for each channel, and an internal valid transfer request is generated when the condition of the channel buffer status is satisfied.
[0157]
The channel buffer status is a signal indicating the state of the data buffer 740 for data transfer of each transfer channel. The data buffer 740 of the channel contains an “empty” state in which no valid data is contained and valid data is contained. There are two states, “full”.
[0158]
In the case of memory read transfer from the page memory 404 to the data buffer 740, when the buffer status of the data buffer 740 of the channel to be transferred is “empty”, that is, data can be received, an internal valid transfer request from the request generation unit 923 Occurs.
[0159]
In the case of memory write transfer from the data buffer 740 to the page memory 404, when there is valid data in the data buffer 740 of the channel to be transferred and the buffer status is “full”, the request generation unit 923 internally validates the valid data. A transfer request occurs.
[0160]
The request mask circuit 922 controls whether or not to validate the transfer request created by the request generation unit 923 in the previous stage.
[0161]
The transfer channel enable determines whether transfer of the channel is permitted or not.
[0162]
The TC mask is used to control the transfer amount. The number of words to be transferred is set in advance in the terminal counter 745. When the predetermined number of words is transferred, the TC mask becomes active and the transfer of the channel is prohibited. When the transfer amount control is not performed, the TC mask is always inactive by setting.
[0163]
The FIFO control mask controls transfer permission / prohibition of the channel when performing FIFO control. The FIFO control mask is active and transfer prohibited, and inactive and transfer permitted.
[0164]
Whether the FIFO control is performed based on the FIFO status from the FIFO address generators 635 and 636, the comparison result of the transfer comparator of the terminal counter 745, or the FIFO control is not selected is selected by setting from the system CPU 11. When the FIFO control is not performed, the FIFO control mask is always inactive by setting.
[0165]
The page memory transfer request arbitration unit 921 arbitrates transfer requests for eight channels generated by the request mask circuit 922, selects one channel, and selects the address generator selection signal (RCHN) set in the selected channel as an address. Output to the control unit 26.
[0166]
The priority control of arbitration performed when transfer requests are generated from a plurality of channels is round robin control in which the priority of the channel that performed the previous transfer is the lowest when channels 1 to 8 are arranged in a ring shape. . Therefore, even if all the 8 channels continue to issue a transfer request, the order is always reached while the transfer is performed 8 times, so that the transfer is performed equally for each channel.
[0167]
Next, a detailed configuration of the terminal counter 745 of FIG. 17 will be described with reference to FIG. The terminal counter 745 counts the number of transfer words for each channel, and includes a countdown signal generator 931, a transfer word number counter 932 for eight channels, and four transfer number comparators 933 connected to one of the two channels. It is configured.
[0168]
The countdown signal generator 931 outputs a countdown signal to the transfer channel signal based on the arbitration result of the image bus priority controller 741 and the transfer word number counter 932 of the selected channel according to the transfer end signal.
[0169]
The transfer word number counter 932 is a 32-bit binary down counter that is counted down every time one transfer of the image bus 29 of the channel is completed. Here, the initial value of the counter 745 is set by the system CPU 11 via the system bus 16. A terminal count signal is output when carry-down occurs.
[0170]
The value of the transfer word number counter 932 can be read from the system CPU 11 via the system bus 16 at any time.
[0171]
The interrupt mask circuit 934 enables / disables interrupts to the system CPU with respect to the 8-channel terminal count signals, and outputs a logical sum of these as a terminal count interrupt signal. The system CPU 11 sets permission / non-permission of each channel.
[0172]
The transfer number comparator 933 compares the transfer word numbers of the two channels and activates the output as a comparison result when the transfer word numbers are equal.
[0173]
Further, the transfer number comparison 933 can compare each transfer word number to be compared by arbitrarily multiplying it by a setting. Usually, each is used by doubling. For example, if A is set to twice and B is set to 1 for two channels A and B, the comparison result becomes active when the number of A transfer words reaches ½ of the number of B transfer words. This comparison result is used as a control signal when performing FIFO control between two channels.
[0174]
Next, the operation in the above configuration will be described. First, a basic operation for inputting image data from the scanner 13 to the page memory 28 will be described. The image output data of 8 bits / pixel of the document read by the scanner 13 is transferred to the image data interface 210 through the image processing circuit 14 as scanner image data of 8 bits / pixel, 4 bits / pixel, 2 bits / pixel, or 1 bit / pixel. A plurality of pixels (4, 8, 16, 32 pixels) of the scanner image data are collected inside the image data interface 210 and DMA-transferred to the data control circuit 27 via the image bus 29 as transfer data in units of 32 bits.
[0175]
The data control circuit 27 writes 32-bit scanner image data to the address of the page memory 28 generated by the address control circuit 26.
[0176]
Next, processing for compressing image data on the page memory 28 will be described. The page memory 28 is logically divided into an image area 28a for storing image data and a code area 28b for storing compressed code data.
[0177]
In the image data transfer control unit 701, two channels are set as transfer paths from the image area 28a of the page memory 28 to the compression / expansion circuit 211 and from the code output of the compression / expansion circuit 211 to the code area 28b of the page memory 28.
[0178]
Further, by using the hard disk interface 34 or the optical disk interface 37 as the code output transfer destination, a large amount of images can be recorded on a recording medium with a lower bit unit.
[0179]
After making various settings for compression processing in the compression / decompression circuit 211, an encoding start command is executed.
[0180]
Image data is read from the page memory 28 and input to the compression / decompression circuit 211. The compression / decompression circuit 211 encodes the image and outputs the code to the code area 28 b of the page memory 28.
[0181]
Next, a process for decompressing encoded image data into the page memory 28 will be described. In the image data transfer control unit 701, two channels are set as a transfer path from the code area 28b of the page memory 28 to the compression / decompression circuit 211 and from the image output of the compression / decompression circuit 211 to the image area 28a of the page memory 28. In addition, by using the hard disk interface 34 or the optical disk interface 37 as the code input transfer source, it is possible to record a large amount of images stored in a recording medium with a lower cost per bit.
[0182]
After making various settings for decompression processing in the compression / decompression circuit 211, a decoding start instruction is executed.
[0183]
The code data is read from the page memory 28 and input to the compression / decompression circuit 211. The compression / decompression circuit 211 decodes the image and outputs the image data to the image area 28 a of the page memory 28.
[0184]
Next, a printer output operation from the page memory 28 to the printer 15 will be described. First, image data is output from the page memory 28 to the printer 15. The 32-bit unit image data specified by the address of the page memory 28 generated by the address control circuit 26 is transferred to the data control circuit 27 and then DMA-transferred to the image data interface 210 via the image bus 29.
[0185]
A part of the image data interface 210 converts 32-bit image data into a bit number of 4 bits / pixel or 2 bits / pixel or 1 bit / pixel for output to the printer 15 and transfers it to the printer 15 through the image processing unit 14. Is output.
[0186]
As described above, the image input operation from the scanner 13 to the page memory 28, the image data compression processing on the page memory 28, the decompression processing of the encoded image data to the page memory 28, and the page memory 28 to the printer 15 The basic operation of the printer output operation is performed.
[0187]
Next, electronic sorting will be described with reference to FIG. Electronic sorting reads a plurality of originals to be sorted, temporarily stores them in a storage device such as a semiconductor memory, a hard disk, or an optical disk, and outputs an arbitrary number of stored images in an arbitrary order. By doing so, it is possible to output the pages input later and arrange the page order of the print output, or to output a plurality of copies in the page order. FIG. 22 shows an example of electronic sorting. When four originals are sequentially input as shown in the figure, in the case of group output, the necessary number of copies are output in order from the last input original. Since the paper output later is jammed, the first input document is jammed and output at the top.
[0188]
On the other hand, in the case of sort output, one copy is output in the reverse order of document input, and this is repeated as many times as necessary.
[0189]
Here, before explaining the compression / decompression operation of the present invention, a conventional compression / decompression operation will be described.
[0190]
FIG. 23 shows the timing of scanner input and encoding processing.
[0191]
The scanner input and the encoding process proceed simultaneously. When the scanner 13 finishes inputting the first page, after the read preparation time ta for the next page such as the carriage back of the scanner 13 or the setting of the document by the document feeder, the next is performed. The scanner input for this page is started, and if there are subsequent pages, the same operation is repeated to accumulate the original image.
[0192]
FIG. 24A shows a state of the image area 28a of the page memory 28 at the time of scanner input and encoding processing.
[0193]
The image data written from the scanner 13 to the image area 28a of the page memory 28 is read out in the same order as it is written, and is encoded.
[0194]
When the scanner input and the encoding process proceed simultaneously, the reading control is performed so that the reading of the encoding process does not overtake the writing from the scanner 13 to the image area 28a of the page memory 28.
[0195]
FIG. 25 shows the timing of decoding processing and printer output at the time of non-rotating output.
[0196]
First, the first page is decrypted.
[0197]
Next, the printer output of the first page and the decoding of the next page proceed simultaneously.
[0198]
When the output of the first page is completed, output preparation for the second page such as paper capture is performed, and output of the second page and encoding of the third page are started.
[0199]
FIG. 24B shows the state of the image area 28a of the page memory 28 at the time of non-rotational output and printer output and decoding processing.
[0200]
The page memory in which the image of the first page has already been developed is sequentially read and output to the printer, and the decoded image data of the next page is written in the empty area already output to the printer 15.
[0201]
When the printer output and the decoding process are performed simultaneously, the writing of the decoded image data of the next page to the image area 28a of the page memory 28 does not overtake the reading of the currently output page to the printer 15. Write control is performed as described above.
[0202]
FIG. 26 shows the timing of the decoding process and the printer output at the time of rotation output.
[0203]
First, the first page is decrypted.
[0204]
Next, the image on the image area 28 a of the page memory 28 is read in the rotation direction, and the rotated image data is output to the printer 15.
[0205]
All the image data for one page is read out and output to the printer 15, and then the image of the next page is expanded.
[0206]
FIG. 27A shows a state of decoding into the image area 28 a of the page memory 28. As shown in the figure, the image is decoded from the upper left to the lower right on the page memory.
[0207]
FIG. 27B shows a state of rotating and reading out the image data decoded in the image area 28a of the page memory 28 and outputting it to the printer. In this example, it is rotated 90 degrees clockwise, and the image data is read from the lower left to the upper right as shown in the figure.
[0208]
Since the decoding order of the image to the image area 28a of the page memory 28 and the rotation reading are different in the access order, the decoding image of the next page cannot be written during the rotation reading, and the decoding of the next page is completed. Until then, the printer output was stopped because the rotation could not be read.
[0209]
Therefore, a wasteful time tp in which no printer output is performed and a wasteful time td in which no decoding process is performed are generated, which degrades the performance of the system.
[0210]
The present invention is to reduce the above-described useless times tp and td as much as possible when performing image decoding processing and printer processing using the image area 28a of the page memory 28 for one page. Three methods for doing this will be described below.
[0211]
First, the first method will be described.
[0212]
In the first method, when rotation is necessary at the time of output, the decoded image is not rotated and read out, and is output for rotation, but is rotated when the image read from the scanner 13 into the image area 28a of the page memory 28 is encoded. The image that has been read out and rotated in advance is encoded.
[0213]
Whether to encode only the non-rotated image, only the rotated image, or both the non-rotated image and the rotated image is selected according to the direction required at the time of printer output.
[0214]
If it is known that only non-rotated images are required as printer output, only non-rotated images are encoded. Similarly, when only the rotation output is necessary, the rotation image is encoded.
[0215]
Also, when both non-rotated and rotated images are required as printer output, for example, when images are output alternately as non-rotated and rotated by groups, both non-rotated and rotated images are encoded during encoding. Turn into.
[0216]
FIG. 28 shows the timing when the image input of the scanner 13 and both the non-rotated image and the rotated image are encoded.
[0217]
First, when the scanner input for the first page is started, the image data read from the scanner 13 is written into the image area 28 a of the page memory 28.
[0218]
At the same time, the encoding process is started, and the image data written from the scanner 13 to the image area 28a of the page memory 28 is sequentially encoded.
[0219]
Since the encoding process is sufficiently faster than the input speed of the scanner 13, the encoding of the same page is completed almost simultaneously with the input end of the scanner 13.
[0220]
The encoded data (compressed data of the non-rotated image) as the encoded output is written in the code area 28b of the page memory 28.
[0221]
When the encoding of the non-rotated image is completed, the image already written in the image area 28a of the page memory 28 by the scanner 13 is read in the rotation direction, and the rotated image is encoded.
[0222]
The encoded data (compressed data of the rotated image) as the encoded output is written in another area of the code area 28b of the page memory 28.
[0223]
Since the image data is already in the image area 28a of the page memory 28 at the time of encoding the rotated image, it can be encoded without waiting for the data from the scanner 13 as at the time of encoding the non-rotated image.
[0224]
When the input of the first page is completed, the scanner 13 starts the scanner input for the next page after the read preparation time ta for the next page such as the carriage back of the scanner 13 or the setting of the document by the automatic document feeder, and thereafter If there is a subsequent page, the same operation is repeated to store the encoded data for the document image.
[0225]
The state of the image area 28a of the page memory 28 at the time of encoding processing of the scanner input, non-rotated image, and rotated image will be described in order.
[0226]
FIG. 29A shows scanner input to the image area 28a of the page memory 28 and reading of image data to be encoded in the non-rotating direction.
[0227]
As shown in the figure, the scanner input is scanned line by line from the upper left of the image area 28a of the page memory 28 to the lower right of the figure, and written to the image area 28a of the page memory 28.
[0228]
Similarly, reading of image data to be encoded in the non-rotating direction sequentially reads and encodes images written by the scanner 13 in the same order as the scanner input.
[0229]
At this time, the overtaking prevention control is performed for the reading of the image data to be encoded so that the reading of the image data to be encoded does not pass the writing position of the scanner 13.
[0230]
Since the encoding process is sufficiently faster than the input speed of the scanner 13, the encoding process catches up with the scanner input, and waits for the next image data to be written from the scanner 13 by the overtaking prevention control.
[0231]
Therefore, the scanner input for one page and the read encoding process of the same image are almost completed.
[0232]
FIG. 29B shows reading of image data to be encoded in the rotation direction of the image area 28 a of the page memory 28.
[0233]
In the figure, the readout is rotated 90 degrees clockwise by reading from the lower left to the upper right.
[0234]
Therefore, the image data to be encoded is (c) in FIG. 29 at the time of non-rotational reading and (d) in FIG.
[0235]
Next, a description will be given of an output operation in which an image (encoded data) accumulated in the code area 28b of the page memory 28 by the above encoding process is decoded and output to a printer in a desired order.
[0236]
The selection of rotation or non-rotation of the output image can be switched by decoding the image encoded in the direction required for the output image, so that the operation timing is the same as the conventional decoding processing at the non-rotation output, printer output ( It becomes the same as FIG.
[0237]
Therefore, even when a rotated image is output, it is possible to perform continuous processing as in the case of outputting a non-rotated image, and the processing speed can be improved.
[0238]
The state of the image area 28a of the page memory 28 for the printer output and decoding process is the same as the conventional decoding process and printer output (FIG. 24B) at the time of non-rotation output.
[0239]
Even when the rotated image is decoded and output, the operation is the same only by using the image area 28a of the page memory 28 as a horizontal image.
[0240]
Next, the second method will be described.
[0241]
In the second method, encoding is performed in the non-rotation direction simultaneously with the scanner input, and the output image is rotated by reading out the image decoded in the non-rotation direction in the rotation direction and outputting it to the printer.
[0242]
Conventionally, the decoded image of the next page has not been written during the rotational reading of the image area 28a of the page memory 28, whereas in the present invention, the rotational reading is performed without waiting for the completion of the rotational reading for one page. By partially writing the decoded data of the next page into the vacant area that has already been read out by the printer 15, the processing speed can be increased by simultaneously performing the rotation output of the current page and the decoding process of the next page. It has improved.
[0243]
Since the scanner input and encoding process, the non-rotating printer output and the decoding process are the same as those in the prior art, the rotating printer output and decoding process having different operations will be described in detail.
[0244]
FIG. 30 shows the operation timing of the rotary printer output and decoding processing.
[0245]
First, the decoded data for the entire image of the first page is written into the image area 28 a of the page memory 28.
[0246]
Next, rotation reading of the image area 28a of the page memory 28 is performed, and rotation printer output is started. In this example, the image data decoded on the image area 28a of the page memory 28 is rotated 90 degrees in the clockwise direction, so that it is rotated from the left half side on the image area 28a of the page memory 28.
[0247]
When all the left halves on the image area 28a of the page memory 28 have been read, the left half of the second page has already been read and the decoded data is written in the vacant area.
[0248]
Further, when the printer 15 has finished reading the right half of the image area 28a of the page memory 28, the right half of the second page is read and the decoded data is written in the empty area.
[0249]
When the output of the first page is completed, the printer 15 starts the output of the second page after completing the preparation of the output of the next page such as taking in paper.
[0250]
The state of the image area 28a of the page memory 28 at the time of the decoding process and the rotation printer output will be described in order.
[0251]
FIG. 31A shows a state in which the decoded data of the entire image of the first page is written.
[0252]
Next, rotation reading of the image area 28a of the page memory 28 is performed, and rotation printer output is started. In this example, the image data decoded on the image area 28a of the page memory 28 is rotated 90 degrees in the clockwise direction, so that reading is performed from the lower left to the upper right in the figure.
[0253]
FIG. 31B shows a state in which the rotational reading of the left half of the image area 28a of the page memory 28 has been completed.
[0254]
At this point, since the left half of the image area 28a of the page memory 28 is already an empty area read to the printer 15, the image of the next page (F in the example shown in the figure) is stored in the left half area. Decrypted data is written in the left half of
[0255]
At this time, partial decoding of the image of the next page (left half in the example in the figure) and writing to the image area 28a of the page memory 28 are necessary, but the encoded data itself encodes the entire image. Since it was obtained, partial writing can be performed using the following method.
[0256]
In the case of an encoding method and apparatus that can specify the decoding of only the portion required when decoding the entire encoded data into the original image, only the required portion is decoded and the image area 28a of the page memory 28 is decoded. Write to.
[0257]
If partial decoding is impossible when decoding the entire code data into the original image, the page memory 28 is subjected to a process of cutting out only the necessary portion from the decoded entire image. Is written in the image area 28a. Alternatively, the entire image writing operation is performed on the image area 28 a of the page memory 28, but the data on the image area 28 a of the page memory 28 is not rewritten except for the area that needs to be written. There is a method of setting the image area 28a.
[0258]
For example, as a process of cutting out only a necessary portion from the decoded entire image, a cutting unit 215 is provided between the compression / decompression circuit 211 and the image bus 29 as shown in FIG. In accordance with an instruction from the circuit 21, the cutout unit 215 may selectively cut out the left half, the right half, and all of the decoded data for each line decompressed by the compression / decompression circuit 211.
[0259]
FIG. 31 (c) shows a state in which the output of the right half of the first page and the writing of the decoded data of the left half of the second page have been completed and rotational printing of the left half of the second page is about to start. Show.
[0260]
At this time, since the right half of the first page has been rotated and read, writing of the decoded data to the right half of the second page is in progress.
[0261]
FIG. 31D shows a state where the rotation reading of the left half of the second page has been completed.
[0262]
In the example shown in the figure, writing of the decoded data in the left half of the third page is about to start.
[0263]
Thereafter, if there is a subsequent page, the same operation is repeated.
[0264]
In this way, continuous rotation print output can be performed in the same manner as non-rotation print output using the image area 28a of the page memory 28 for one page.
[0265]
Next, the third method will be described.
[0266]
In the third method, when rotating printer output is required, an image is divided at the time of encoding and a plurality of areas are encoded and stored simultaneously in order to continuously perform rotating output at the time of output.
[0267]
Therefore, when it is known that the output is a non-rotating printer, the entire page is encoded as one image as usual without dividing the image.
[0268]
Similar to the second method, the output image is rotated by reading out the image decoded in the non-rotation direction in the rotation direction and outputting it to the printer.
[0269]
Conventionally, the decoded image of the next page is not written during the rotational reading of the image area 28a of the page memory 28.
[0270]
On the other hand, in the present invention, the decoded image of the partial next page divided at the time of encoding into the vacant area that has already been read to the printer 15 in the rotation direction without waiting for the end of the rotation reading for one page. I am writing.
[0271]
As a result, the rotation output of the current page and the decoding process of the next page proceed simultaneously to improve the processing speed.
[0272]
FIG. 32 shows the timing when the image input of the scanner 13 and the left half and the right half of the input image are encoded simultaneously.
[0273]
The scanner input and the encoding process proceed simultaneously, and the image data written from the scanner 13 to the image area 28a of the page memory 28 is read out independently for the left half and the right half and is encoded.
[0274]
In addition, when the respective encoding processes are simultaneously performed, the reading control is performed so that the reading from the respective encoding processes does not pass the writing from the scanner 13 to the image area 28a of the page memory 28.
[0275]
The state of the image area 28a of the page memory 28 at the time of the scanner input and encoding process will be described in order.
[0276]
FIG. 33A shows the scanner input to the image area 28a of the page memory 28 and the encoded reading of the left and right areas.
[0277]
As shown in the figure, the scanner input is scanned line by line from the upper left of the image area 28a of the page memory 28 to the lower right of the figure, and written to the image area 28a of the page memory 28.
[0278]
The encoding process sequentially encodes the image data written by the scanner 13 for the left and right areas.
[0279]
At this time, overtaking prevention control is performed on the encoded reading so that the reading of the encoding does not pass the writing position of the scanner 13.
[0280]
Since the encoding process is sufficiently faster than the input speed of the scanner 13, each encoding process catches up with the scanner input and waits for the next image data to be written from the scanner 13 by the overtaking prevention control.
[0281]
Therefore, the scanner input for one page and the read encoding process of the same image are almost completed.
[0282]
At this time, the images encoded by the respective encoding processes are shown in FIGS. 33B and 33C.
[0283]
If there is a subsequent document, it is divided into left and right areas in the same way, encoded, accumulated as a code, and this is repeated.
[0284]
Next, an output operation for decoding the images accumulated by the above encoding processing in a desired order, non-rotating printer output, and rotating printer output will be described.
[0285]
FIG. 34 shows the timing of the decoding processing of the divided and encoded image and the output of the non-rotating printer.
[0286]
First, prior to printer output, the left half and the right half of the first page are each decoded.
[0287]
When the decoding of the entire first page is completed, the printer output is started and the decoding of the second page proceeds simultaneously.
[0288]
In the decoding of the second page, decoding and writing are performed in the left half and right half empty areas by the respective decoding processes for the empty areas read by the printer output.
[0289]
Since the decoding process is sufficiently faster than the reading of the printer output, the decoding of the second page is completed almost simultaneously with the end of the output of the first page.
[0290]
Thereafter, the same operation is repeated for the necessary pages.
[0291]
FIG. 35A shows the state of the image area 28a of the page memory 28 at the time of decoding the first page printer output and the second page divided and encoded image.
[0292]
FIG. 35 (b) shows a state where the printer output of the first page and the decoding of the second page have further progressed.
[0293]
Since the decoding process is sufficiently faster than reading the printer output, the image writing of the decoding process catches up with the image reading of the printer output, so overwriting prevention control is performed so that the writing of the decoding process does not overtake the reading of the printer output. Has been done.
[0294]
The decoding process of the image divided and decoded into the left half and the right half and the output timing of the rotary printer are the same as those in the method 2 (FIG. 30).
[0295]
First, when the left half and the right half of the first page are decoded and the entire surface of the first page is decoded, the rotational read printer output is started.
[0296]
Each time one half of the image area 28 a of the page memory 28 is read, the half of the next page is decoded and written to the image area 28 a of the page memory 28.
[0297]
Thereafter, if there are subsequent pages, the same operation is repeated.
[0298]
In this way, continuous rotation print output can be performed in the same manner as non-rotation print output using the image area 28a of the page memory 28 for one page.
[0299]
The difference from Method 2 in the rotation output operation is that encoding is performed for each of the left and right regions at the time of encoding, so that the code for the region (left side or right side) required for decoding at the time of rotation output is obtained. The data is decrypted and written into the image area 28 a of the page memory 28.
[0300]
The three methods for continuously obtaining the rotated output image by using the image area 28a of the page memory 28 for one page have been described above. The scanner input and encoding processing and the printer necessary for performing these methods have been described. The overtaking prevention control at the time of transfer for simultaneously performing the output and the decoding process will be described.
[0301]
First, the overtaking prevention control of the image data writing from the scanner 13 to the image area 28a of the page memory 28 and the encoded reading of the written image data will be described.
[0302]
The state of the image area 28a of the page memory 28 at this time is shown in FIG.
[0303]
The number of transfers from the scanner 13 to the image area 28 a of the page memory 28 and the number of transfers read out by encoding are counted by the respective transfer word number counters 932. The two transfer numbers are compared by the transfer number comparison 933, and when the comparison results are equal, the encoded reading is prohibited. By doing so, it becomes impossible to encode more image data inputted from the scanner 13, and overtaking can be prevented.
[0304]
As another method, there is a method of comparing a write address and a read address in the image area 28a of the page memory 28.
[0305]
Writing and reading to and from the image area 28a of the page memory 28 are performed on one-dimensional continuous addresses on the physical address of the image area 28a of the page memory 28, so the relationship between the number of transfers and the physical address is equivalent. is there. That is, having the same number of transfers is equivalent to accessing the same address.
[0306]
Therefore, it is possible to prevent overtaking by comparing the read address of the encoding and the write address of the scanner 13 and prohibiting the read of the encoding when they are equal.
[0307]
Next, a description will be given of the control for preventing the next page decryption writing from overtaking the printer output reading at the time of non-rotating output.
[0308]
The state of the image area 28a of the page memory 28 at this time is shown in FIG.
[0309]
As in the case of encoding, the number of transfer words for printer output reading and decoding writing is counted and decoding writing is prohibited when equal, or the reading address and writing address of the image area 28a of the page memory 28 are compared. If it becomes equal, overwriting can be prevented by prohibiting writing.
[0310]
Next, a description will be given of the control for preventing the reading of the printer output at the time of continuous rotation output from overwriting by decoding the next page.
[0311]
The state of the image area 28a of the page memory 28 at this time is shown in FIG.
[0312]
First, the transfer number of half of one page is set in the transfer word number counter 932 as the transfer number of rotation reading to the printer 15, and an interrupt is generated to the system CPU 11 when the transfer number is reached.
[0313]
When rotation reading is started and rotation output of the left half is completed, an interrupt is generated for the system CPU 11.
[0314]
This triggers writing to the decoding of the left half of the next page.
[0315]
Since the area has already been read, there is no effect on the right half of the image data currently being output.
[0316]
When the rotation output of the entire page, that is, the output of the remaining right half is completed, writing to the decoding of the right half of the next page is started.
[0317]
Next, a description will be given of the control for preventing the reading of the encoded data in the left and right areas from overtaking the writing from the scanner 13 to the image area 28a of the page memory 28.
[0318]
The state of the image area 28a of the page memory 28 at this time is shown in FIG.
[0319]
The left and right areas are divided so that the transfer amount is equal.
[0320]
Therefore, it is only necessary to perform control so that the number of read transfers of encoded data in each region does not exceed 1/2 of the number of write transfers of the scanner 13.
[0321]
Therefore, when comparing the write transfer number of the scanner 13 and the read transfer number of the encoded data, the encoded data transfer number is set to be doubled and the read of the encoded data is prohibited when the transfer numbers become equal. To prevent overtaking.
[0322]
Further, the scanner write address in the image area 28a of the page memory 28 is compared with the read address of the encoded data, and the read of the encoded data is prohibited when the read address is equal to or higher than the write address, thereby preventing overtaking.
[0323]
Finally, a description will be given of the control for preventing the writing of the decoded data of the next page from overtaking the printer output reading when the image divided and encoded in the left and right regions is non-rotated.
[0324]
The state of the image area 28a of the page memory 28 at this time is shown in FIG.
[0325]
The left and right areas are divided so that the transfer amount is equal.
[0326]
Therefore, it is only necessary to perform control so that the transfer number of decrypted data written in each area does not exceed 1/2 of the printer read transfer number.
[0327]
Therefore, when comparing the numbers of transfers, the number of transfers of decoded data is set to double, and when the numbers of transfers become equal, reading of the encoded data is prohibited to prevent overtaking.
[0328]
Further, the overwriting is prevented by comparing the write address of the decoded data in the image area 28a of the page memory 28 with the address for reading out the printer output, and prohibiting the decoding write when the write address is equal to or higher than the read address.
[0329]
As described above, non-rotated and rotated images are encoded and stored at the time of scanner input, and an image in a necessary direction is decoded at the time of output. The non-rotation encoding / accumulation is performed at the time of scanner input, and the free space generated at the time of rotation output is partially decoded. The image is divided and encoded / accumulated in the main scanning direction at the time of scanner input, and is decoded when there is an empty area corresponding to the divided area at the time of rotation output.
[0330]
Thereby, in the electronic sort of the digital copying machine, the scanner input, the encoding, the decoding, and the rotation / non-rotation printer output can be continuously processed in the image memory of the single page page memory.
[0331]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to provide an image forming apparatus capable of continuously processing read input, encoding, decoding, and rotation / non-rotation image formation output with an image memory for one page. .
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is an overall block diagram illustrating a control circuit of the image forming apparatus.
FIG. 3 is a block diagram showing a configuration of a basic unit.
FIG. 4 is a block diagram showing a configuration of a system basic unit.
FIG. 5 is a block diagram showing a configuration of a system expansion unit.
FIG. 6 is a block diagram illustrating a configuration of an image processing circuit.
FIG. 7 is a block diagram showing a configuration of a system control circuit.
FIG. 8 is a block diagram showing a configuration of a communication memory access control circuit.
FIG. 9 is a block diagram showing a configuration of a page memory access control circuit.
FIG. 10 is a block diagram showing a configuration of an address control circuit.
FIG. 11 is a block diagram showing a configuration of an address generation unit.
FIG. 12 is a diagram illustrating an example of an address generation direction of an address generation unit.
FIG. 13 is a diagram showing a configuration of a FIFO address generator.
FIG. 14 is a diagram showing a concept in the case of two-dimensional access to a page memory.
FIG. 15 is a diagram showing a two-dimensional access of a page memory by a linear address.
FIG. 16 is a block diagram showing a configuration of a data control circuit.
FIG. 17 is a block diagram showing a configuration of an image data transfer control unit.
FIG. 18 is a diagram showing a configuration of a timer.
FIG. 19 is a block diagram showing a detailed configuration of an image bus priority control unit.
FIG. 20 is a block diagram showing a detailed configuration of a page memory priority control unit.
FIG. 21 is a diagram showing a detailed configuration of a terminal counter.
FIG. 22 is a diagram showing an example of electronic sorting.
FIG. 23 is a diagram showing timing of conventional scanner input and encoding processing.
FIG. 24 is a diagram for explaining page memory access;
FIG. 25 is a diagram showing timing of conventional non-rotating printer output and decoding processing.
FIG. 26 is a diagram showing the timing of conventional rotary printer output and decoding processing.
FIG. 27 is a diagram for explaining page memory access;
FIG. 28 is a diagram showing the timing of scanner input and encoding processing.
FIG. 29 is a diagram for explaining page memory access;
FIG. 30 is a diagram illustrating the timing of rotation printer output and decoding processing.
FIG. 31 is a diagram for explaining page memory access;
FIG. 32 is a diagram showing the timing of scanner input and encoding processing.
FIG. 33 is a diagram for explaining page memory access;
FIG. 34 is a diagram showing the timing of non-rotating printer output and decoding processing.
FIG. 35 is a diagram for explaining page memory access;
FIG. 36 is a block diagram showing a configuration of a system basic unit.
[Explanation of symbols]
11 ... System CPU
13 ... Scanner
14 Image processing circuit
15 ... Printer
28 ... Page memory
28a ... Image area
28b ... Code area
211 ... Compression / decompression circuit

Claims (9)

Reading means for reading image data of a document;
First storage means for storing image data read by the reading means in an image memory for storing image data for one page;
First reading means for reading image data stored in the image memory by the first storage means in a non-rotating direction and a rotating direction;
Encoding means for encoding the image data in the non-rotating direction and the image data in the rotating direction read by the first reading means;
Second storage means for storing the code data in the non-rotation direction and the rotation direction encoded by the encoding means in a code memory for storing code data for a plurality of pages;
Decoding means for selectively decoding the non-rotating direction or rotating direction code data stored in the code memory by the second storage means into image data;
Third storage means for storing in the image memory the image data in the non-rotating direction or the rotating direction decoded by the decoding means;
Second reading means for reading image data in the non-rotating direction or rotating direction stored in the image memory by the third storing means;
Image forming means for forming an image on an image forming medium using image data in the non-rotating direction or rotating direction read by the second reading means;
Comprising
The image data stored in the image memory is read in the non-rotating direction by the first reading means and encoded by the encoding means, and then the image data stored in the image memory is read in the rotating direction by the first reading means. An image forming apparatus, wherein encoding is performed by an encoding unit. Reading means for reading image data of a document;
First storage means for storing image data read by the reading means in an image memory for storing image data for one page;
First reading means for reading the image data stored in the image memory by the first storage means in the non-rotating direction and the rotating direction;
Encoding means for encoding the image data in the non-rotating direction and the image data in the rotating direction read by the first reading means;
Second storage means for storing the code data in the non-rotation direction and the rotation direction encoded by the encoding means in a code memory for storing code data for a plurality of pages;
Decoding means for selectively decoding code data in the non-rotating direction or rotating direction stored in the code memory by the second storage means into image data;
Third storage means for storing, in the image memory, image data in the non-rotation direction or the rotation direction decoded by the decoding means;
Second reading means for reading image data in the non-rotating direction or the rotating direction stored in the image memory by the third storing means;
Image forming means for forming an image on an image forming medium using image data in the non-rotating direction or rotating direction read by the second reading means;
Comprising
The image data stored in the image memory is simultaneously stored in the image memory by the first storage unit and the image data stored in the image memory by the first reading unit is read in the non-rotating direction. After the data is read in the non-rotating direction by the first reading means and encoded by the encoding means, the image data stored in the image memory is read in the rotating direction by the first reading means and encoded by the encoding means. An image forming apparatus. Reading means for reading image data of a document;
First storage means for storing image data read by the reading means in an image memory for storing image data for one page;
First reading means for reading image data stored in the image memory by the first storage means in a non-rotating direction and a rotating direction;
Encoding means for encoding the image data in the non-rotating direction and the image data in the rotating direction read by the first reading means;
Second storage means for storing the code data in the non-rotation direction and the rotation direction encoded by the encoding means in a code memory for storing code data for a plurality of pages;
Decoding means for selectively decoding the non-rotating direction or rotating direction code data stored in the code memory by the second storage means into image data;
Third storage means for storing in the image memory the image data in the non-rotating direction or the rotating direction decoded by the decoding means;
Second reading means for reading image data in the non-rotating direction or rotating direction stored in the image memory by the third storing means;
Image forming means for forming an image on an image forming medium using image data in the non-rotating direction or rotating direction read by the second reading means;
Comprising
The storage of the image data in the image memory by the first storage means and the reading of the image data stored in the image memory in the non-rotation direction by the first reading means from the image memory by the first reading means The number of data transferred is controlled so as not to exceed the number of data transferred to the image memory by the first storage means, and is simultaneously performed. The image data stored in the image memory is non-rotated by the first reading means. An image forming apparatus characterized in that after reading and encoding by an encoding means, image data stored in an image memory is read in a rotation direction by a first reading means and encoded by an encoding means. Reading means for reading image data of a document;
First storage means for storing image data read by the reading means in an image memory for storing image data for one page;
First reading means for reading image data stored in the image memory by the first storage means in a non-rotating direction and a rotating direction;
Encoding means for encoding the image data in the non-rotating direction and the image data in the rotating direction read by the first reading means;
Second storage means for storing the code data in the non-rotation direction and the rotation direction encoded by the encoding means in a code memory for storing code data for a plurality of pages;
Decoding means for selectively decoding the non-rotating direction or rotating direction code data stored in the code memory by the second storage means into image data;
Third storage means for storing in the image memory the image data in the non-rotating direction or the rotating direction decoded by the decoding means;
Second reading means for reading image data in the non-rotating direction or rotating direction stored in the image memory by the third storing means;
Image forming means for forming an image on an image forming medium using image data in the non-rotating direction or rotating direction read by the second reading means;
Comprising
The storage of the image data in the image memory by the first storage means and the reading of the image data stored in the image memory in the non-rotation direction by the first reading means are the same as the reading address by the first reading means. The image data stored in the image memory is read in the non-rotating direction by the first reading means and encoded by the encoding means, An image forming apparatus, wherein image data stored in a memory is read in a rotation direction by a first reading unit and encoded by an encoding unit. Reading means for reading image data of a document;
First storage means for storing image data read by the reading means in an image memory for storing image data for one page;
First reading means for reading image data stored in the image memory by the first storage means;
Encoding means for encoding the image data read by the first reading means;
Second storage means for storing code data encoded by the encoding means in a code memory for storing code data for a plurality of pages;
Decoding means for decoding the code data stored in the code memory by the second storage means into image data;
Third storage means for dividing the image data decoded by the decoding means and storing it in the image memory;
Second reading means for selectively reading the image data divided and stored in the image memory by the third storage means in the non-rotating direction or the rotating direction;
Image forming means for forming an image on an image forming medium using image data in the non-rotating direction or rotating direction read by the second reading means;
Comprising
The decoded image data is stored in one divided area of the image memory by the third storage means, and the image data stored in the other divided area of the image memory is read in the rotation direction by the second reading means. An image forming apparatus which is performed simultaneously. Reading means for reading image data of a document;
First storage means for storing image data read by the reading means in an image memory for storing image data for one page;
First reading means for dividing the image data stored in the image memory by the first storage means into a plurality of areas and reading them;
Encoding means for encoding the image data divided into a plurality of areas read by the first reading means;
Second storage means for storing code data corresponding to a plurality of regions encoded by the encoding means in a code memory storing code data for a plurality of pages;
Decoding means for decoding code data corresponding to a plurality of areas stored in the code memory by the second storage means into image data;
Third storage means for dividing the image data corresponding to the plurality of areas decoded by the decoding means and storing them in the image memory;
Second reading means for selectively reading image data corresponding to a plurality of areas divided and stored in the image memory by the third storage means in a non-rotating direction or a rotating direction;
Image forming means for forming an image on an image forming medium using image data in the non-rotating direction or rotating direction read by the second reading means;
Comprising
The divided storage of the decoded image data corresponding to one area in the image memory by the third storage means and the rotation direction of the image data corresponding to the other area stored in the image memory by the second reading means. Is read out at the same time. A bit image image from a document is read, the read bit image image is stored in an image area for one page of the page memory, and the bit image image stored in the image area is compressed and stored in the code area of the page memory. In the image forming apparatus that decompresses the compressed image stored in the code area into a bit image image, stores the compressed image in the image area, and forms an image on the image forming medium using the bit image image stored in the image area.
When compressing the bit image image stored in the image area and storing it in the code area of the page memory, the bit image image stored in the image area is read without being rotated as it is, and is compressed and encoded in the page memory. Storage means for storing in the area, rotating and reading out the bit image image stored in the image area, compressing and storing it in another area of the code area of the page memory;
A reading means for selectively reading a non-rotated compressed image or a rotated compressed image stored in the code area by the storage means;
The non-rotated compressed image or the rotated compressed image read by the reading means is expanded into a bit image image and stored in the image area, and the bit image image stored in the image area is used on the image forming medium. Image forming means for forming an image on
An image forming apparatus comprising: A bit image image from a document is read, the read bit image image is stored in an image area for one page of the page memory, and the bit image image stored in the image area is compressed and stored in the code area of the page memory. In the image forming apparatus that decompresses the compressed image stored in the code area into a bit image image, stores the compressed image in the image area, and forms an image on the image forming medium using the bit image image stored in the image area.
The compressed image stored in the code area is expanded into a bit image image and stored in a part of the image area, and the expanded bit image image stored outside the part of the image area is rotated. An image forming apparatus characterized in that reading in a direction is simultaneously performed and image formation is performed on an image forming medium using the read rotated bit image. A bit image image from a document is read, the read bit image image is stored in an image area for one page of the page memory, and the bit image image stored in the image area is compressed and stored in the code area of the page memory. In the image forming apparatus that decompresses the compressed image stored in the code area into a bit image image, stores the compressed image in the image area, and forms an image on the image forming medium using the bit image image stored in the image area.
When the bit image image stored in the image area is compressed and stored in the code area of the page memory, the bit image image is compressed by dividing it into a part of the image area and a part of the image area. First storage means for storing in the code area of the page memory as one compressed image;
A second storage means for decompressing one compressed image and the other compressed image for one image stored in the code area into a bit image image and storing them in a partial area of the image area and outside the partial area; ,
When a bit image image is stored in a part of the image area or outside the part of the image area by the second storage means, the bit image image is stored in a part of the image area or a part of the area. Reading means for simultaneously reading the expanded bit image image in the rotation direction;
Image forming means for forming an image on an image forming medium using the rotated bit image image read by the reading means;
An image forming apparatus comprising:

Images