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BACKGROUND OF THE INVENTION
The present invention relates to a document circulating apparatus
applicable to an electronic mail system.
Offices in general are equipped with various kinds of data processing
apparatuses, e.g., copiers, printers, facsimile apparatuses and personal
computers. The data processing apparatuses deal with circulation documents
for the transfer or data, collected data, data to be sent to a different
section, data to be stored, etc. However, notebook type personal computers
are used in a stand-alone condition and, therefore, cannot be constructed
into a network easily. Moreover, most of the documents generated by
personal computers are sent in the form of hard copies, so that it is
troublesome to, for example, set the environment for direct transmission.
Facsimile apparatuses have a problem that users have to walk up to them,
and a problem that users are apt to overlook received documents meant for
them.
Further, data dealt with in offices flood on desks and are often lost or
cannot be distinguished with ease. Since a substantial period of time is
necessary for the data to be circulated, it is impossible to read
necessary data when such data are required. Persons in offices each copies
desired data, increasing the number of papers. Whether or not data are
transferred to a person who needs them cannot be determined. It is
difficult to assign security to a particular member or to set up a
priority order. As the number of times of meeting increases data
representing a place, time and so forth get confused. In addition,
telephones often force persons to get neighbors and leave messages in an
awkward procedure.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a document
circulating apparatus easy to operate and supporting the transfer and
storage of data.
In accordance with the present invention, a document circulating apparatus
has an image reading device, a memory for storing image data and document
data, a controller for controlling the memory, a system constructing
section for constructing a network system, and an image outputting device.
The apparatus automatically deletes, among the image data and the document
data stored in the storing means, particular data.
The apparatus of the type described may transfer part of the image data and
document data input to the memory to terminals via the network system.
When the apparatus additionally includes an optical disk, it may
selectively copy or shift the image data and document data between a
memory on the network and the optical disk.
Also, in accordance with the present invention, a document circulating
device has an image reading device, a memory for storing image data and
document data, a controller for controlling the memory, a system
constructing section for constructing a network system, an image
outputting device, and a terminal unit connected to the network system and
having a function of displaying part of the image data and document data
transferred thereto and a function of requesting, if necessary, transfer
of all the image data and document data.
Further, in accordance with the present invention, a document circulating
apparatus has an image reading device, a memory for storing image data and
document data, a controller for controlling the memory, a system
constructing section for constructing a network system, an image
outputting device, and an OCR section for extracting character data from
the output of the image reading device. The apparatus transfers part of
the image data and document data to a terminal over the network system.
Moreover, in accordance with the present invention, a document circulating
apparatus has an image reading device, an automatic document feeder, a
memory for storing image data and document data, a controller for
controlling the memory, a system constructing section for constructing a
network system, an image outputting device, and an OCR section for
extracting character data from the output of the image reading device. The
apparatus transfers part of the image data and document image to a
terminal over the network system.
In addition, in accordance with the present invention, a document
circulating apparatus has an image reading device, a memory for storing
image data and document data, a controller for controlling the memory, a
system constructing section for constructing a network system, an image
outputting device, an OCR section for extracting character data from the
output of the image reading device, and an OMR section for extracting a
mark. The apparatus transfers part of the image data and document data to
a terminal over the network system.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present
invention will become more apparent from the following detailed
description taken with the accompanying drawings in which:
FIG. 1 is a section showing a document circulating apparatus embodying the
present invention;
FIGS. 2 and 3 are respectively a plan view and a side elevation showing an
optical writing section included in the embodiment;
FIG. 4 is a schematic block diagram showing a control unit included in the
embodiment;
FIGS. 5 and 6 are block diagrams schematically showing, when combined, a
more specific arrangement of the control unit;
FIG. 7 is a schematic block diagram showing an image scanner section
included in the control unit;
FIG. 8 is a schematic block diagram showing an image processing unit
included in the image scanner; FIG. 9 shows data types selectively output
from the image processing unit;
FIG. 10 is a block diagram schematically showing a memory system included
in the control unit;
FIG. 11 demonstrates a system wherein image data from the image processing
unit are once written to a memory device included in the memory system;
FIG. 12 shows a system wherein processed image data and raw data from the
image processing unit both are written to the memory device;
FIG. 13 is a block diagram schematically showing a specific construction of
the memory device;
FIG. 14 is a schematic block diagram showing a memory unit included in the
memory device of FIG. 13;
FIG. 15 shows three different image data types;
FIG. 16 is a block diagram schematically showing another specific
construction of the memory device;
FIG. 17 is a block diagram showing an arrangement for storing image data by
using an external storage;
FIG. 18 is a block diagram schematically showing still another specific
construction of the memory device;
FIG. 19 is a schematic block diagram of a system section included in the
control unit;
FIG. 20 is a schematic block diagram of a control circuit included in the
system section;
FIG. 21 shows storage areas defined in a hard disk;
FIG. 22 is a section showing an alternative embodiment of the present
invention;
FIG. 23 is a block diagram schematically showing a system section included
in the alternative embodiment;
FIGS. 24 and 25 are block diagrams schematically showing, when combined, a
more specific construction of a control unit included in the embodiment of
FIG. 22;
FIG. 26 is a schematic block diagram showing a specific construction of a
memory block included in the control unit of the alternative embodiment;
FIG. 27 shows a bar code mark; and
FIG. 28 shows a specific document carrying a bar code mark thereon.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1 of the drawings, a document circulating apparatus
embodying the present invention is shown. As shown, the apparatus is
generally made up of six units, i.e., an apparatus body A, an ADF
(Automatic Document Feeder) 151, a sorter C, a turn-over unit D, a system
section E, and an OCR section F. The apparatus body A has a scanner
section, a writing section, a photoconductive element section, a
developing section, and a sheet feed section.
The various sections mentioned above are constructed and operated as
follows.
Scanner Section
A first scanner is loaded with a reflector 1, a light source 3, and a first
mirror 2 and movable at a constant speed. A second scanner is loaded with
a second mirror 4 and a third mirror 5 and movable at a speed which is one
half of the speed of the first scanner. When the first and second scanners
optically scan a document, not shown, laid on a glass platen 9, the
resulting imagewise reflection from the document is routed through a color
filter 6 and a lens 7 to a monodimensional solid state imaging device 8.
While the light source 3 is generally implemented by a fluorescent lamp or
a halogen lamp, a fluorescent lamp is predominant since it has a stable
wavelength and long life. Although the embodiment uses a single light
source, two or more light sources may be used. Since the imaging device 8
has a constant sampling clock, the fluorescent lamp 3 should be turned on
at a frequency higher than the sampling clock; otherwise, it would
adversely effect images.
Generally, the imaging device 8 is implemented by a CCD (Charge Coupled
Device) image sensor. The analog image signal from the imaging device 8 is
converted to a digital image signal and then subjected to various kinds of
image processing (bilevel or multilevel conversion, tonality processing,
magnification change, editing, etc.) at an image processing board 10. The
resulting digital signal is an aggregation of spots. To produce color
image data, the embodiment has a color filter 6 movable into and out of an
optical path extending from the document to the imaging device 8, thereby
passing only the data of required color. The color filter 6 is moved into
or out of the optical path in synchronism with the scanning of the
document. Every time the color filter 6 is so moved, a multiplex image
transfer function or a duplex copy function enabled to produce various
kinds of copies.
Writing Section
The processed image data are written on a photoconductive drum 40 in the
form of an aggregation of beam spots by the raster scanning of a laser
beam. Specifically, a laser beam issuing from a semiconductor laser 20 is
collimated by a collimator lens 21 and then shaped by an aperture 32 to
have a predetermined shape. The shaped laser beam is compressed by a first
cylinder lens 22 in the subscanning direction and then incident to a
polygon mirror 24. The polygon mirror 24, having an accurate polygonal
section, is rotated by a polygon motor 25 at a predetermined speed in a
predetermined direction. The rotation speed of the polygon mirror 24 is
determined by the rotation speed and writing density of the drum 40 and
the number of faces of the mirror 24.
The laser beam incident to the polygon mirror 24 is steered by the mirror
24 which is in rotation. The beam from the mirror 24 is sequentially input
to f-theta lenses 26a and 26b. The f-theta lenses 26a and 26b convert the
scanning beam having a constant angular velocity such that it scans the
drum 40 at a constant speed. As a result, the the beam is focused onto the
drum 40 as a minimum beam spot. In addition, the f-theta lenses 26a and
26b are provided with a mechanism for compensating for irregularities in
the configuration of the polygon mirror 24. The beam passed through these
lenses 26a and 26b is steered by a mirror 29 to a synchronizing section 30
located outside of an image region. In the synchronizing section 30, the
beam is propagated through an optical fiber to a sensor. After a
synchronizing signal indicative of the beginning of a line in the main
scanning direction has appeared, one line of image data is output on the
elapse of a predetermined period of time. This is repeated to complete a
single image.
Photoconductive Element Section
The drum 40 has a photoconductive layer on the periphery thereof. The
photoconductive layer may be implemented by an organic photoconductor
(OPC), .alpha.-Si, Se-Te or similar substance sensitive to a semiconductor
laser (wavelength of 780 nm). The embodiment uses an organic
photoconductor. Generally, for laser beam writing, there are available a
negative-to-positive (N/P) process which illuminates an image portion, and
a positive-to-positive (P/P) process which illuminates a background. In
the illustrative embodiment, use is made of the N/P process.
A main charger 41 is of the conventional scotorton type having a grid on
the drum 40 side. The charger 41 uniformly charges the surface of the drum
40 to negative polarity. The laser beam incident to the charged surface of
the drum 40 lowers the potential thereof. As a result, the potential on
the surface of the drum 40 becomes -750 V to -800 V in the background or
about -500 V in the image portion, forming an electrostatic latent image.
A main developing unit 42a and an auxiliary developing unit 42b, to which
a bias of -500 V to -600 V is applied, each deposits toner on a developing
roller thereof so as to develop the latent image.
Developing Section
In the event of development in black only, the auxiliary developing unit
42b and a toner replenishing unit 43b are removed. A toner replenishing
unit 43a is associated with the main developing unit 42a and stores black
toner therein. The toner replenishing unit 43b associated with the
auxiliary developing unit 42b stores color toner. While a latent image is
developed in one color, the main pole of the other developing unit may be
changed. The development is combined with the reading of color data, which
is effected by the replacement of the color filter 6, and the multiplex
image transfer function and duplex copy function available with the sheet
transport system. This implements multifunction color copying and color
editing. For development in three or more colors, three or more developing
units may be arranged around the drum 40, or a revolver accommodating such
developing units may be used.
As a sheet is fed in synchronism with the drum 40, the image developed by
the developing units 42a and 42b is transferred to the sheet by a transfer
charger 44. For this purpose, the transfer charger 44 applies a positive
charge to the rear of the sheet. A separation charger 45 constructed
integrally with the transfer charger 44 and separates the sheet carrying
the image thereon from the drum 40 by an AC discharge. After the image
transfer, the toner left on the drum 40 is removed by a cleaning blade 47
and collected in a tank 48. Further, the potential pattern also left on
the drum 40 is erased by a discharge lamp 49.
A photosensor 50 is positioned just after the developing position and
comprised of a light emitting element and a light-sensitive element. At
the writing position, a predetermined pattern, e.g., black or mesh pattern
is written to the position of the drum 40 corresponding to the photosensor
50. After the predetermined pattern has been developed, the photosensor 50
determines the reflectance of the developed pattern and that of the other
portion of the drum 40. A ratio between these reflectances is indicative
of the density of the image. If the density is low, a toner replenish
signal is output. When the density does not increase even after the
replenishment, it may be determined that the amount of toner is short.
Sheet Feed Section
In the illustrative embodiments, sheet cassettes 60a, 60b and 60c are each
loaded with a stack of sheets of particular size. A sheet carrying an
image on one side thereof may be passed through a refeed loop 72 for the
purpose of duplex copying or refeeing. After one of the cassettes 60a-60c
has been selected, a start button is pressed. Then, a pick-up roller 61
(61a, 61b or 61c), adjoining the cassette 60 selected, starts rotating and
feeds a sheet until the leading edge of the sheet abuts against a
registration roller 61 which is in a halt.
The registration roller 62 starts rotating at a timing matching the image
formed on the drum 40, thereby driving the sheet toward the periphery of
the drum 40. After the transfer of the image from the drum 40 to the
sheet, a separating and conveying section 63 conveys the sheet by sucking
it. Subsequently, a heat roller 64 and a pressure roller 65, constituting
a fixing unit, fix the toner image on the sheet. In an ordinary copy mode,
the sheet coming out of the fixing unit is directed by a path selector 67
toward an outlet communicating to the sorter C. In a multiplex copy mode,
the sheet is again guided by path selectors 68 and 69 toward the register
roller 62 via the refeed loop 72.
While a duplex copy mode may be selectively implemented only by the
apparatus body A or by the combination of the apparatus body A and
turn-over unit D, the following description will concentrate on the
combination scheme. The sheet steered downward by the path selector 67 is
directed further downward by the path selector 68 and then directed by the
path selector 69 toward a tray 70 located below the refeed loop 72. A
roller 71 turns over the sheet and feeds it in the opposite direction. At
this instant, the path selector 69 is so positioned as to steer the sheet
to the registration roller 62 via the refeed loop 72.
ADF B
The ADF automatically feeds a stack of documents one by one to the glass
platen 9 and drives them out after copying. Specifically, documents are
stacked on a table 100 and neatly positioned by side guides 101 in the
widthwise direction. A pick-up roller 104 separates one of the documents
from the others and feeds it out of the tray 100. A conveyor belt 102
conveys the document to a predetermined position on the glass platen 9.
After the document on the glass platen 9 has been copied a desired number
of times, it is driven out to a tray 103. It is possible to determine the
document size on the basis of the positions of the side guides 101 and by
counting the feed time of the document.
Sorter C
The sorter has bins 111a-111x and distributes copies sequentially coming
out of the apparatus body A to designated ones of the bins 111a-111x.
Specifically, as a plurality of rollers are driven by a motor 110 to feed
the consecutive copies, pawls adjoining the inlets of the bins 11 I steer
the copies into the associated bins 111.
Turn-Over Unit D
While the apparatus body A can produce only a single two-sided or duplex
copy at a time, the turn-over unit D allows a plurality of duplex copies
to be produced collectively when combined with the apparatus body A. To
produce a plurality of duplex copies collectively, the sheet carrying an
image on one side thereof and steered downward by a discharge roller 66 is
directed toward the turn-over unit D by the path selector 67. Such sheets
are sequentially stacked on a tray 123 by a discharge roller 120. At this
instant, a feed roller 121 and a side guide 122 cooperate to neatly
arrange the sheets in the vertical and horizontal directions. In the event
of rear copying, the sheets are sequentially refed from the tray 123 by a
refeed roller 124. At this time, the path selector steers the sheets
directly into the refeed loop 72.
There are also shown in FIG. 1 a sound-proof glass 23, a mirror 27, a
dust-proof glass 28, a lens retainer unit 31, a sheet separator 46, a main
motor 80, and a fan motor 81.
Electric Control Section
Referring to FIG. 4, a control unit for controlling the entire apparatus
has a main control board 140, a sheet feed control board 141, a duplex
copy control board 142, a sorter control board 143, an ADF control board
144, and a scanner control circuit 213. The control boards and circuit
control sensors and solenoids shown in the figure. The reference numerals
214, 221, 225 and 263 respectively designate an application system, a CCD
image sensor, an IPU (Image Processing Unit), and a memory unit. As shown
in FIGS. 5 and 6 in detail, the control unit has two CPUs (Central
Processing Units), i.e., a sequence control CPU 201 and a main CPU 202
which are respectively assigned to sequence control and operation control.
The CPUs 201 and 202 are connected together by a serial interface
(RS232C).
The sequence control will be described first. A sequence sets and outputs
conditions relating to the sheet transport and image formation. Connected
to the sequence control CPU 201 are sensors 203 relating to sheet
transport and including size sensors, discharge sensor and registration
sensor, a duplex copy unit 204, a high-tension power source unit 205,
drivers 206 for driving relays, solenoids and motors, a sorter unit 207, a
laser beam scanner unit 208, an image control circuit 209, etc. Regarding
the sensors 203, the CPU 201 receives the outputs of size sensors
responsive to the size and orientation of sheets and outputting electric
signals indicating them, sensors responsive to registration and sheet
discharge, sensors responsive to an oil end condition, toner end condition
and other supply conditions, and sensors responsive to a door left open,
blowing of a fuse and other mechanical errors.
The duplex copy unit 204 includes a motor for regulating the width of
sheets, a sheet feed clutch, a solenoid for steering sheets, a sheet
presence/absence sensor, a size fence home position sensor for regulating
the width of sheets, and sensors relating to sheet transport. The
high-tension power source unit 205 applies to each of the main charger,
transfer charger, separation charger and bias electrode for development a
particular high voltage by a particular duty determined by PWM (Pulse
Width Modulation) control. The drivers 206 respectively drive a sheet feed
clutch, registration clutch, counter, motor, toner replenishing solenoid,
power relay, fixing heat, etc. The CPU 201 is connected to the sorter unit
207 by a serial interface and causes it to convey sheets and discharge
them into the bins at a predetermined timing in response to signals from
the sequence.
A fixing temperature, photosensor output, laser diode monitor input and
laser diode reference voltage are applied to the analog input of the CPU
201. Receiving the output of a thermistor included in the fixing unit, the
CPU 201 ON/OFF controls the heater or controls the phase thereof such that
the fixing unit remains at a predetermined temperature. A photosensor, or
phototransistor, senses a photosensor pattern formed at a predetermined
timing and sends the output thereof to the CPU 201. In response, the CPU
201 determines the density of the pattern and then ON/OFF controls a toner
replenishing clutch, thereby controlling the toner concentration. Also,
the CPU 201 uses the pattern density in detecting a toner end condition.
An analog-to-digital converter (ADC) and the analog input of the CPU 201
are used for maintaining the power of the laser diode constant.
Specifically, the monitor voltage when the laser diode is turned on is
controlled to a predetermined reference voltage (which is selected such
that the laser diode is 3 mw).
The main or operation control CPU 202 controls a plurality of serial ports
and a calender IC (Integrated Circuit) 211. Connected to the serial ports
are an operation panel 212, a scanner control circuit 213, an application
214, an editor 215 and so forth as well as the sequence control CPU 201.
The operation panel 212 has indicators for displaying operator's key
inputs and conditions of the copier. The key inputs are reported to the
main CPU 202 by serial communication. In response, the CPU 202 determines
whether or not to turn on the indicators of the operation panel 212 and
then sends the result of decision to the panel 212 by serial
communication. As a result, the operation panel 212 turns on or turns off
the indicators as instructed by the CPU 202.
The scanner control circuit 213 sends information relating to scanner servo
motor drive control and image processing to the main CPU 202 by serial
communication. Also, the circuit 213 interfaces the ADF (B), FIG. 1, to
the CPU 202. The application 214 interfaces external apparatus, e.g.,
facsimile apparatus or printer to the CPU 202 and interchanges
predetermined information with them. The editor 2 15 is accessible to
effect an inputting and editing function. Image editing data (masking,
trimming, image shift, etc.) entered by the operator on the editor 215 is
sent to the CPU 202 by serial communication. The calender IC 211 stores
date and time and can be accessed by the CPU 202, as needed. With the
calender IC 211, it is possible to display the current time on the
operation panel 212 and to set desired times for turning on and turning
off the machine.
The gate array 216 sends, in response to a select signal from the main CPU
202, image data (DATA0-DATA7) and synchronizing signals in any of the
following three different directions.
(1) Scanner Control Circuit 213.fwdarw.Image Control Circuit 209
Image signals in the form of eight-bit data (or four-bit or one bit data,
if desired) and serially transferred from the scanner are sent to the
image control circuit 209 in synchronism with a synchronizing signal
PMSYNC from the laser beam scanner unit 208.
(2) Scanner Control Circuit 213.fwdarw.Application 214
Image signals serially sent from the scanner in the form of one-bit data
(binary) are output to the application 214 in parallel. The application
214 sends the input image data to a printer or similar output device
connected to the apparatus.
(3) Application 214.fwdarw.Image Control Circuit 209
As a facsimile apparatus or similar input device serially inputs image
signals in the form of one-bit data (binary) to the application 214, the
application transfers them to the image control circuit 209 in synchronism
with the synchronizing signal PMSYNC from the laser beam scanner unit 208.
As image signals in the form of one-bit data (binary) are serially input
from a facsimile apparatus or similar external input device to the
application 214, the application 214 transfers them to the image control
circuit 209 in synchronism with the synchronizing signal PMSYNC from the
laser beam scanner unit 208.
As shown in FIG. 7, the analog image signal from the CCD image sensor 221
is applied to a signal processing circuit 222 to be amplified and to have
the quantity of light thereof corrected thereby. The output of the signal
processing circuit 222 is transformed to a digital multilevel signal from
an ADC 223. The digital signal is processed by a shading correction
circuit 224 and then input to an IPU (Image Processing Unit) 225.
As shown in FIG. 8, the image signal input by the IPU 225 has the high
frequency components thereof enhanced by an MTF (Modulation Transfer
Function) correction circuit 231, electrically changed in magnification by
a magnification change circuit 232, and then applied to a gamma (.gamma.)
correction circuit 233. This correction circuit 233 optimizes the input
and output characteristic in matching relation to the characteristic of
the machine. A data depth switching mechanism has two switches 234 and
235. The switch 234 transforms the image signal from the correction
circuit 233 to a predetermined quantization level. The data depth
switching mechanism implements three different data types shown in FIG. 9.
A four-bit circuit 236 outputs four-bit data. A binarizer 237 binarizes
input eight-bit multilevel data to produce binary data, or one-bit data,
by use of a predetermined threshold. A dither circuit 238 produces area
tonality based on the one-bit data. The switch 234 selects one of the
three different data types and outputs it as DATA0-DATA7.
Referring again to FIG. 7, the scanner control circuit 213 controls a lamp
stabilizer (lamp control circuit)241, a timing control circuit 242, an
electric magnification change circuit 232 of the IPU 225 (FIG. 8), and a
scanner drive motor 243, as instructed by the printer control section. The
lamp stabilizer 241 ON/OFF controls the fluorescent lamp 244 and controls
the quantity of light to issue from the lamp 244, as instructed by the
scanner control circuit 213. A rotary encoder 245 is connected to the
output shaft of the scanner drive motor 243. A position sensor 246 senses
a reference position assigned to a subscanning drive mechanism. The
magnification change circuit 232 effects an electric magnification change
according to main scanning magnification data set by the scanner control
circuit 213.
The timing control circuit 242 outputs various kinds of signals in response
to commands from the scanner control circuit 213. Specifically, when the
scanner starts reading a document, the timing control circuit 242 sends to
the CCD image sensor 221 a transfer signal for transferring one line of
data to a shift register, and shift clock pulses for outputting the data
of the shift register one bit at a time. The timing control circuit 242
sends a pixel synchronous clock pulses CLK, main scanning synchronizing
pulses LSYNC and main scanning valid period signals LGATE to control units
responsive to the image reproducing system. The pixel synchronous clock
pulses CLK are substantially identical with the shift clock pulses applied
to the CCD image sensor 221. The main scanning synchronizing pulses LSYNC
are substantially identical with the signals PMSYNC from the beam sensor
of the image writing unit, but they are synchronous to the pixel
synchronous clock pulses CLK. The main scanning valid period signal LGATE
goes high at the time when the output data (DATA0-DATA7) are regarded as
valid data. In the illustrative embodiment, the CCD image sensor 221
outputs 4,800 bits of valid data for each line.
On receiving a read start command from the printer control section, the
scanner control circuit 213 turns on the lamp 244, starts driving the
scanner drive motor 243, controls the timing control circuit 242, and
thereby causes the CCD image sensor 221 to read an image. Further, the
scanner control circuit 213 causes a subscanning valid period signal FGATE
to go high. The signal FGATE, gone high goes low on the elapse of a period
of time necessary for the maximum readable length in the subscanning
direction (longitudinal dimension of A4 size in the embodiment) to be
scanned.
The image signal from the image sensor 221 is output in the form of
eight-bit data, FIG. 9, via an IPP 251 having a shading correction
function, black level correcting function, and light quantity correcting
function. These data are selected by a first multiplexer (MUX1) 252,
processed by the IPU 225 having a spatial high frequency enhancing (MTF
correction) function, speed changing (magnification change) function,
gamma correcting function, and data depth converting function (eight
bits/four bits/1 bit), and then sent to a printer PR via a third
multiplexer (MUX3) 254. Designated by the reference numeral 255 is a
memory device (MEM).
As shown in FIG. 11, it has been customary to write the image data from the
IPU 225 in the MEM 255 and transfers them from the MEM 255 to the PR, as
needed. It has also been customary to write the image data in the MEM 255
while sending them to the PR at the same time and to implement the second
and successive copies with image data stored in the MEM 255. The
embodiment allows data to flow as shown in FIG. 12, so that both the
processed data and the raw data from the IPU 225 may be written to the MEM
255. For this purpose, three multiplexers (MUX1, MUX2 and MUX3) shown in
FIG. 10 are switched over to change the flow of the data. For example, to
produce a plurality of copies by a single scanning step while changing the
parameter of the IPU 225:
(a) When the scanner scans a document, a single copy is output with the
MUX1, MUX2 and MUX3 selecting A, B and A, respectively. In this condition,
raw data are written to the MEM 255 via the MUX2; and
(b) For the second and successive copies, the MUX1 selects B to transfer
the data from the MEM 255 to the IPU 225 and therefrom to the PR via the
MUX3. Every time a copy is produced, the parameter of the IPU 225 is
changed.
To store one-bit data or similar compact data, the MUX1 selects A so as to
write the output of the IPU 225 in the MEM 255. In this case, the PR
selects a bilevel data (one bit) mode. In FIG. 10, labeled EXT IN and EXT
OUT are image data received from the outside and image data to be sent to
the outside.
A specific construction of the MEM 255 will be described with reference to
FIG. 13. As shown, the MEM 255 has a compressor (COMP) 261 and an expander
(EXP) 262 respectively preceding and following a memory unit 263, so that
not only actual data but also compressed data may be written to the memory
unit 263. The prerequisite with this configuration is that the COMP 261
and the EXP 262 be respectively operated speeds matching the speeds of the
scanner and printer. To store actual data in the memory unit 263, a MUX4
264 and a MUX5 265 both select A; to store compressed data, they select B.
The reference numeral 266 designates an error detector.
As shown in FIG. 14, the memory unit 263 has a memory block 272 and two
data width converters, i.e., an input data width converter 271 and an
output data width converter 275 respectively connected to the input and
the output of the memory block 272. These converters 271 and 275 allow the
memory unit 263 to deal with both the three different image types shown in
FIG. 15 and the compressed data or code data. Direct memory controllers
(DMA1 and DMA2) 273 and 274 read and write data in the predetermined
addresses of the memory block 272 matching the number of packed data and
the memory data width. Usually, the rate of image data from the scanner or
to the printer remains constant without regard to the data type, i.e.,
eight-bit data, four-bit data or one-bit data. That is, the period of a
single pixel is fixed in an apparatus.
In the illustrative embodiment, the data are sequentially defined as
one-bit data, four-bit data and eight-bit data from the MSB (Most
Significant Bit) side of the eight data lines. The input data width
modulator 271 and output data width modulator 275 respectively pack and
unpack such data in and from the data width (sixteen bits) of the memory
block 272. By packing data, it is possible to use a memory matching a data
depth and, therefore, to promote the efficient use of the memory device
255.
Another specific construction of the memory unit is shown in FIG. 16. As
shown, the MEM 255 has a PPU (Pixel Processing Unit) 281 in place of the
COMP 261 and EXP 262. The PPU 281 is a unit capable of implementing
logical operations (e.g., ANDing, ORing, EORing and NOTing) with the image
data. Specifically, the PPU 281 is capable of performing logical
operations with the memory output data and input data and sending the
resulting data to the printer or writing the resulting data again in the
memory unit 263. The printer, or destination of the data, and the memory
unit 263 are switched over by a MUX6 282 and a MUX7 283. This kind of
function is usually used to combine images, e.g., to store overlay data in
the memory unit 263 and lay them over scanner data.
FIG. 17 shows a specific construction wherein image data are stored by use
of an external memory device. As shown, a floppy disk 295 is mounted to a
floppy disk drive (FDD) 294. To write image data in the floppy disk 295,
the image data from the EXT OUT, FIG. 10, are sent to a floppy disk
controller (FDC) 293 via an interface (I/F) 291 under the control of a
file controller 292. As a result, the image data are written to the floppy
disk 295. The file controller 292 also controls a hard disk controller
(HDC) 296 and a hard disk drive (HDD) 297, so that image data may be
written and read out of a hard disk. The HI)l) 297 stores format data and
overlay data to be used often. The reference numeral 298 designates a line
drawer.
Referring to FIG. 18, another specific configuration of the memory device
will be described. The MEM 255 to be described is capable of effecting a
100% recovery when the compression speed and expansion speed were short.
As shown, compressed data and image data are input to the memory unit 263
at the same time as scanning. While the two kinds of input data are each
written to a particular memory area, the compressed data are directly
applied to the EXP 262 and expanded thereby. Assume that the processing of
the COMP 261 and that of the EXP 262 were in time and completed before the
entry of one full page of data in the memory unit 263. Then, only the
memory area assigned to the compressed data is left while the area
assigned to the raw data is cancelled. When the error detector 266 detects
an error signal output from the COMP 261 or EXP 262 | | |
