JPH02153383A - Compound function copying machine - Google Patents

Abstract

PURPOSE:To keep a machine from being down and to continue copying by setting a digital copying mode in the case that a developing device which should be used in an analog copying mode cannot be used. CONSTITUTION:The copying machine is started and a selected mode is checked. In the analog mode, whether or not toner exists in the developing devices 23-25 is decided and the control of an illuminating lamp 4, the driving of a photosensi tive body 21, the control or the processing of an electrophotographic system, the driving of a conveying system and the control of a fixing part are performed. Next, the control of feeding paper, the setting of a collapsible mirror 4, the scanning of an optical system, the control of a resist roller 37 and the return of the optical system are performed until completion as long as the machine is normal. When the machine does not work normally, the display of an error is performed and the machine is returned to setting by warming up and setting a condition. Since the digital copying is possible even if the analog copying becomes impossible, copying is continued by switching to the digital mode.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a multifunctional copying machine having an analog copying function and a digital copying function.

(Prior Art) Copying machines using an electrophotographic process include digital copying machines that copy digital images and analog copying machines that copy analog images.

A digital image in a digital copying machine is obtained by projecting a dot-shaped optical image onto a photoreceptor based on the digital image signal obtained by reading the original image with a photoelectric conversion element and converting it into a binary digital electric signal. It will be done. Digital image signals can be processed by digital electric circuits, so the advantage of digital copiers is that they allow editing such as cutting and pasting images, and they also allow digital image data to be stored and transferred externally. be.

On the other hand, a drawback of digital copying machines is that it is difficult to achieve both halftone reproduction (gradation expression) and resolution. A dither matrix method is generally used to reproduce halftone images, but this method has a low resolution and causes significant image deterioration when copying binary images such as characters. Furthermore, as the resolution increases, the amount of data increases, resulting in a decrease in processing speed and a significant increase in cost. Furthermore, when an image that has been digitally copied is digitally copied again, the image quality deteriorates due to a moiré phenomenon. In addition, re-copying (generation copy) of halftone copy using digital method,
This causes significant image deterioration.

Therefore, at present, analog copying machines and digital copying machines are used depending on the purpose.As a solution to the disadvantages of digital copying machines, electrical image processing is used to achieve both binary and gradation expression. Attempts have been made to cope with generation copying by reducing moiré phenomena through filtering, and to improve image quality by increasing density, but all of these methods require complicated equipment configurations and increase costs. and a decrease in processing speed.

On the other hand, most documents that are copied in a typical office are binary information such as letters, numbers, and line drawings, and are handled as hard copies, including image data with halftones.

Therefore, analog type copying machines have higher cost performance for the work of copying.

Therefore, a multifunction copier that combines analog copying and digital copying functions has been proposed. By using this copying machine, you can use the features of both types depending on the purpose. For example, when recopying a copy using a digital copying method, there is less image deterioration if the copy is made using an analog copying method. Furthermore, it becomes possible to synthesize an analog halftone image and a digital binary image.

For example, an LED head is used as an image writing head for writing digital image data onto a photoreceptor in a multifunctional copying machine. LED heads generate heat when energized to emit light, but this does not affect their lifespan in the long run. The digital image data for image writing Δ and RAD can be used to cause the image area to emit light by inverting the logic, but it is also possible to cause the non-image area to emit light. However, since the image portion has a smaller area within the shell, it is preferable to cause the image writing head to emit light in the image portion. However, when the analog copying function is activated, reflected light from the non-image area is projected onto the photoreceptor. Therefore, if we consider a multifunctional copying machine that uses the functions and structure of an analog copying machine as is and is equipped with an image writing head and peripheral circuits, it is not possible to cause the image area to emit light in a digital image.

Therefore, in another application, the applicant has disclosed a multifunctional copier that uses regular development in analog copying mode and reversal development in digital copying mode.

(Problems to be Solved by the Invention) Incidentally, in this multifunction copying machine, copying cannot be performed in the analog copying mode if the regular developing type developer cannot be used due to some trouble or empty toner. However, since this copier also has a digital copy mode, the toner color (for example, black) of the regular development system developer for analog copying and the toner color of the reversal development system developer for digital copying is particularly important. If they are the same, it would be easier to use if you could switch to digital copy mode and make copies.

The copying machine described in Japanese Patent Application Laid-Open No. 56-83757 has a configuration capable of copying by analog positive exposure and writing images by digital negative exposure. Further, the image reading device described in Japanese Patent Application Laid-Open No. 55-123270 uses two optical systems to perform analog writing on a photoreceptor and digital reading using a CCD element. However, none of them mention mode switching.

An object of the present invention is to provide a multifunctional copying machine that can perform copying using either analog or digital methods and avoids machine downtime as much as possible even when trouble occurs.

(Means for Solving the Problems) A multifunctional copying machine according to the present invention includes a photoreceptor on which an electrostatic latent image of an original is formed, and an optical system that projects an image of the original on the original plate onto the photoreceptor. , an image sensor means on which an original image is projected through an optical path common to the optical system up to the vicinity of the photoreceptor; and a dot-shaped image on the photoreceptor in response to an electrical signal of the original image read by the image sensor means. An image writing head for projecting a light image, a first developer using a regular development method in which the unexposed area of the photoreceptor is made visible with toner, and a first developer using a reversal development method in which the exposed area of the photoreceptor is made visible with toner. A second developer, a transfer device that applies a voltage to transfer the toner image onto paper, and an analog copy mode that uses the first developer and a digital copy mode that uses an image sensor, an image writing head, and the second developer. a selection means for selecting, and a copy control means for operating the first developer and the second developer, respectively, and setting the polarity of the voltage of the transfer device in response to the selection of the analog copy mode and the digital copy mode by the selection means. The copying control means is characterized in that, when the first developing device cannot be used in the analog copying mode, settings of copying conditions are switched to correspond to the digital copying mode.

(Function) In the multifunction copying machine according to the present invention, when the analog copy mode is selected, the first developing device is activated, the voltage polarity of the transfer device is set corresponding to regular development, and the scanning optical The electrostatic latent image of the original image formed on the photoreceptor by the system is normally developed.

When the digital copy mode is selected, the original image is projected onto the image sensor by an optical path converting means (a foldable mirror, a semi-transparent mirror, etc.), and then digitized. At the same time as it is activated, the voltage polarity of the transfer device is switched to reverse development, and the image writing head performs image exposure on the photoreceptor according to the digitized image data, and the electrostatic charge that is formed is The latent image is developed in reverse.

When the first developing device using the regular developing method cannot be used in the analog copying mode due to a problem such as toner empty, the copying control means automatically switches to the digital copying mode using the second developing device using the reversal developing method. Set by operation to avoid machine down.

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiments) Hereinafter, embodiments of the present invention will be described in the following order with reference to the accompanying drawings.

(a) Overall structure of the copying machine (b) Analog copying (c) Digital copying (d) Rennost control (e) Control system (f) Copying flow Note that when trouble occurs during analog copying, which is a feature of the present invention, The switch to digital copying is explained in section (f) with reference to FIG. 11(b).

(a) Overall configuration of copying machine FIG. 1 shows a schematic configuration diagram of a multifunctional copying machine according to an embodiment of the present invention.

This multifunctional copying machine 1 utilizes the functions and structure of an ordinary analog type electrophotographic copying machine as is, and allows the reflection mirror 14 closest to the photoconductor 21 to be used among the plurality of reflection mirrors that make up the scanning optical system. A line-type C0D (charge-coupled device) image sensor 61 for image reading. It incorporates an LED head 71 and peripheral circuits for the purpose. Then, there is an analog copy mode, a digital copy mode, an image reading mode where the image is read by the COD image sensor 6, and an image is read by the LED head 7!
Equipped with an image writing mode for writing. By adding a communication control unit, it can also be used as a facsimile.

One of the differences from a normal analog copying machine is that in addition to the scanning optical system that scans the reflected light from the original in the analog copy mode, it also incorporates a COD image sensor 61 and an LED head 71 for the digital copy mode. That's true.

In the analog copy mode, an original placed on a transparent glass original table 2 is illuminated by an illumination lamp 4 in an illumination unit 3. The image of the original is captured by a reflecting mirror 5 attached to an illumination unit 3 and a reflecting mirror 7 attached to a mirror unit 6.

8. An image is formed on the photoreceptor 21 on the drum by a scanning optical system composed of a scanning lens lO attached to a lens stand 9, reflection mirrors 12 and 13 attached to a mirror unit 11, and a foldable mirror 14. be done.

On the other hand, in the digital copy mode (image reading mode), the optical system from the original to the image sensor 61 shares the scanning optical system of the analog copy mode up to the foldable mirror 14, and the image sensor 61 is placed at a position optically equivalent to the exposure point. In the digital copying mode (image reading mode), the collapsible mirror 14 is retracted from the optical path, so that the reflected light from the reflective mirror 13 reaches the image sensor 61 without being obstructed by the collapsible mirror 14. In this way, since most of the optical path for reading images in digital copying is shared with the scanning optical system for analog copying, the apparatus can be simplified.

Another difference from a normal analog copying machine is that the polarity of the transfer voltage by the transfer charger 26 can be made positive or negative, and a plurality of developing devices 23, 24, 25 containing toner of different polarities are provided. That's true. That is, regular development was used for analog copying, and reversal development was used for digital copying. There is a band around the photoreceptor 21, as in a normal electrophotographic copying machine. A device 22, developing devices 23, 24, 25, transfer charger 26, cleaning unit 28, and eraser lamp 30 are arranged. And the charger 22
When an electrostatic latent image is formed on the photoreceptor 21 which is uniformly negatively charged, a toner image is formed on the electrostatic latent image by the developing device 23, 24 or 25, and then the toner image is The image is transferred to the paper by transfer charger 26. The toner remaining on the photoreceptor 21 is collected by a cleaning unit 28, and then the photoreceptor 2H is irradiated with an eraser lamp 30 to eliminate static electricity. Note that the toner image on the paper is fixed by the fixing roller 43, and the paper is discharged to the discharge tray 47.

In this process, in analog copy mode, the photoreceptor 2
1, since the reflected light of the document is scanned while it is uniformly charged to a negative polarity by the charger 22, an electrostatic latent image in which the charge remains in the image area is formed. Therefore, a positively charged toner image is formed on the photoreceptor 21 when it is developed by the developing device 23 or 25 having positively charged toner. Therefore, when the polarity of the transfer charger 26 is set to negative, the toner image is transferred to the paper. On the other hand, in the digital copy mode (or image 8-inclusive mode), the LE is applied to the negatively charged photoreceptor 21.
Since the D head 71 emits light in the image area, an electrostatic latent image in which the charge in the image area disappears is formed. Therefore, when development is performed using the developing device 24 containing negatively charged toner, a negatively charged toner image is formed on the portion where the charge disappears (image area). Therefore, if the polarity of the transfer charger 26 is made positive,
The toner image is transferred to the paper.

Note that the LED head 71 used in the digital copy mode (and image writing mode) is provided between the charger 22 and the developer 23.

In this embodiment, the paper is supplied from the paper cassette 31 or 32 to the transfer unit via the registration rollers 37.

In addition, a paper refeeding system consisting of a gate 45 and transport rollers S1 to S54 is provided, and the fixed paper is fed back to the registration rollers 37.
It was possible to transport up to Therefore, it is now possible to perform composite copying in which digital copying is used to write dates and the like on paper that has been subjected to analog copying. The range of applications is expanded because analog and digital images can be combined.

In this embodiment, the foldable mirror 14 is used to switch between the optical path for digital copying and the optical path for analog copying. However, a semi-transparent mirror can also be used instead of the foldable mirror 14. In this case, since the semi-transparent mirror is fixed, no movable parts are required. In analog copying mode, a portion of the light reflected from the original is reflected by a semi-transparent mirror and hits the photoreceptor 21.
to expose. On the other hand, in the digital copy mode, the light transmitted through the semi-transparent mirror is detected by the COD image sensor 61. When writing an image in the digital copying mode, exposure must be performed without exposure from the semi-transparent mirror, so the timings of image reading and image writing are appropriately shifted.

(b) Analog copying mode Since the copying machine of this embodiment is based on the configuration of an analog copying machine, the operation in analog copying mode will be explained next.
Each part of the copying machine will also be explained.

The positions of the illumination unit 3 and mirror unit 6 in FIG. 1 are home positions. When making an analog copy of a document and when reading an image by the image sensor 61, which will be described later,
By a well-known mechanism (not shown), the illumination unit 3 and mirror unit 6 of the scanning optical system are moved leftward in the figure at a predetermined speed to scan the document image in a slit shape.

At this time, the moving speed of the lighting unit 3 and the mirror unit 6
The moving speed of is in a relationship of 2:l, and the optical distance from the document surface to the scanning lens lO is always kept constant.

FIG. 1 shows the position of the scanning optical system when scanning an original image onto the photoreceptor 21 at a magnification of 1=1. The speeds are equal.

The lens stand 9 to which the scanning lens 10 is attached is configured to be movable in the left-right direction in the figure by a not-shown or well-known mechanism, so that the scanning magnification of the document can be changed.

Now, if the scanning magnification of the original is to be doubled, the scanning lens IO is moved to the 10° position shown by the broken line in the figure. 11 is also moved, and the conjugate length is corrected by moving mirrors 12 and 13 to positions of 12° and 13°, respectively, as indicated by broken lines.

Furthermore, since the circumferential speed of the photoreceptor 21 is constant regardless of the scanning magnification, the moving speed of the illumination unit 3 is
It is controlled at a speed of /2.

In this embodiment, the photoreceptor 21 is an OPC drum whose surface is coated with an OPC (organic photoreceptor) layer, and is uniformly charged with a negative (-) by the charger 22.
is charged with electricity.

When a document image is scanned onto the charged photoreceptor 21, the negative charges on the photoreceptor disappear depending on the intensity of the scanning light. That is, the charges in the bright areas of the original disappear, the charges in the dark areas remain, and an electrostatic latent image corresponding to the image of the original is formed.

Developing units 23, 24, and 25 for developing the electrostatic latent image with powder toner are arranged around the photoreceptor.

The developing devices 23, 24, and 25 are set to have different developer toner colors, charging characteristics, etc. In this embodiment, the developing device 23 uses positively charged red toner, and the developing device 24 uses positively charged red toner. The developing device 25 contains negatively charged black toner and positively charged black toner.

The developing device 24 containing negatively charged black toner is provided with a protrusion 91 as shown in FIG.
access. Further, in the case of the developing device 23, 25 into which positively charged toner is placed, a protrusion 92 is provided at the position indicated by the broken line in FIG. Ru. Therefore, switch 93.
94, the polarity of the toner can be determined.

Only one of these developing devices 23, 24, and 25 is enabled to perform development according to an instruction from an operation section (not shown), and the other two are kept in a state in which they do not participate in development.

Assuming that the developing device 25 is selected in the analog copying mode, the negatively charged portion of the electrostatic latent image formed on the photoreceptor 21F is developed by the positively charged black toner, and the electrostatic latent image formed on the photoreceptor 21 A visible image corresponding to the original image is formed. Similarly, when the developing device 23 is selected, a developed image is formed using positively charged red toner. However, when the developer 24 is selected in the digital copy mode, a negative-positive inverted image is formed.

On the other hand, this multifunction copying machine 1 is equipped with paper cassettes 31 and 32 containing copy paper, which can be selected as required.

Assuming that paper cassette 31 is selected now,
One sheet of paper is transferred to the cassette 3 by a pickup roller 33 driven by a signal generated at a predetermined timing.
1 and transported by a transport roller 35,
It stops when the tip reaches the registration roller 37.

Further, when the paper cassette 32 is selected, the pickup roller 34 is driven, and the paper is transported by the transport roller 36 until it reaches the registration roller 37.

As shown in FIG. 3, the registration roller 37 is driven by a drive motor (
(not shown). The paper 40 conveyed from the paper feed cassette is on standby in a state where it collides with the stopped registration rollers 37.

When the leading edge of the image visualized by one of the developing devices reaches a predetermined position, the registration roller 37 is driven by a control circuit to be described later, and the paper 40 is restarted.

When the paper 40 conveyed by the registration rollers 37 comes into contact with the photoconductor 21, the transfer charger 26 applies an electric charge of opposite polarity to the toner from the back side and brings it into close contact with the photoconductor 21, and the toner on the photoconductor 21 is transferred onto the paper. transcribed into.

A high AC voltage is applied to the separation charger 27, whereby the paper is separated from the photoreceptor 21.

Most of the toner on the photoreceptor 2m) is transferred to the paper, but a small amount of toner remains on the photoreceptor 21 without being transferred. This residual toner is removed by the cleaning unit 28
It is scraped off by a cleaning blade 29 installed inside and stored in a collection box (not shown).

In this state, some charge remains on the photoreceptor 211:, so
The entire surface is exposed by the eraser lamp 30, and the initial state is restored.

The paper separated from the photoreceptor 21 is transferred to the suction unit 4.
1 , is conveyed by a conveyor belt 42 , and guided to a fixing roller 43 .

A heater lamp 44 is installed inside the fixing roller 43 to keep the roller surface at a temperature necessary for fusing the toner. The paper to which the toner has been fixed by passing through the fixing section 43 is normally discharged onto the discharge tray 47 by the discharge roller 46 because the gate 45 is located at the solid line position.

On the other hand, in a mode in which data created on a computer or the like is combined and printed on a normal original, the gate 45 is switched to the position shown by the broken line, so the paper on which the original image has been copied is transferred to the transport roller 5.
1, 52, 53, and 54, and reaches the registration roller 37 again and waits.

(c) Digital Copying The above is a description of copying in the normal analog copying mode, and next, image reading and image writing in the dental copying mode will be explained. Note that the case where only image reading is performed is the image reading mode, and the case where only image writing is performed is the image writing mode.

In FIG. 1, the reflecting mirror 14 is of a foldable type.
In the normal analog copying mode, it is at the position shown by the solid line in the figure, and guides the reflected light from the original to the photoreceptor 21, but when reading the original image in the digital copying mode, it is at the position shown by the broken line in the figure. At this time, the reflection mirror 14 is out of the scanning optical path of the scanning optical system, and the original image is formed on the line type image sensor 6.

In this embodiment, the image sensor 61 uses a C0D (charge coupled device) line image sensor. As shown in FIG. 4, this image sensor 61 has 400 light-receiving elements per inch arranged in a straight line, and the total number of elements is about 5000, which means the length of the light-receiving part is about 12 .5 inches.

When the scanning magnification of the scanning optical system is 1x, the original image is 400DP
It is digitized with a resolution of I (dots/inch), and when the scanning lens IO is at the position lO° of the broken line, that is, when magnified twice, the resolution is 800DP+.

In the image sensor 61 shown in FIG. 4, a CCD element 63 is mounted on a ceramic substrate 62, and a transparent protective glass 64 is adhered thereon.

Although COD was used as the image sensor element in this embodiment, an image sensor such as amorphous silicon or CDS may also be used.

In FIG. 1, the image sensor 61 is connected to the scanning lens 10.
The optical distance from the imaging surface of the photoreceptor 21 to the scanning lens 10 is
It is placed at a position that is equal to the distance from The scanning optical system from the original to the mirror 13 is the same as in analog copying.

This makes it possible to make the resolution of document reading by the image sensor 61 variable using the same control means that is used to change the magnification during analog copying.

FIG. 5 is a schematic circuit block diagram of the image sensor section. The image sensor 61 performs photoelectric conversion according to the weight of the received light, and this is amplified by the amplifier 65. The AD converter 66 converts the amplified analog value for each l dot of the light receiving element into a digital value. In this example, 7 bits (2'=
128 level) digital signal.

In general image reading systems, including this embodiment, AD may occur even when reading an original with uniform density due to uneven light intensity of the illumination lamp, reduction in peripheral light intensity due to the scanning lens, and variations in sensitivity of the reading sensor element. The digital value output from the converter 66 is not constant.

Digital values subjected to shading correction are output as read image data via a shading correction ROM 67 and RAM 68 for correcting the influence of variations inherent in the image reading system.

The shading-corrected image data is subjected to halftone processing by an image processing circuit (not shown) or outputted to an external device via an interface unit as necessary, but a description thereof will be omitted here.

FIG. 6 is a schematic structural diagram of the LED head 7X used as an image writing head in this embodiment, and FIG.
7 is a block diagram of a drive circuit for an LED head 71. FIG.

In the LED head 71 shown in FIG. 6, an LED array 7 is placed on a ceramic substrate 72 on which a circuit pattern is printed.
3 and electronic components constituting the drive circuit shown in FIG. 7 are mounted. A transparent protective glass 74 is adhered to the upper surface of the LED array 73 to protect the LED array 73 and the wire bonding portion connecting the drive circuit with the LED array 73 from the external environment.

The SELFOC lens array 76 is formed by arranging a large number of rod lenses 75 with a diameter of about 1 mm, and forms a bit image by scanning a photoreceptor with blinking LED light in response to an input image signal.

The ceramic substrate 72 on which the LED array 73 and drive circuit components are mounted and the SELFOC lens array 76 are arranged at a predetermined distance between the SELFOC lens array 76 and the LED array 73 using fixing fittings (not shown). Fixed.

At this time, an aluminum heat radiating member is attached to the back surface of the ceramic substrate 72 for heat radiation.

In the drive circuit for the LED head 71 not shown in FIG.
1 is! A serial shift register 82 receives image data in the serial shift register 8 in parallel, a serial shift register 83 latches each image data in the parallel shift register 82, and a strobe This is a latch register that outputs during the signal output period. Further, a resistor array 84 for limiting the current flowing through the switching elements and the LEDs is connected to the LED array 73 by wire bonding.

Now synchronize to the image clock! When a line of image data is input to the serial shift register 81, the data in the serial shift register 81 is transferred to the parallel shift register 82 by a shift signal, which is a horizontal synchronization signal, and the data of the next line is transferred to the serial shift register 81. 81
is man-powered.

The next shift signal causes the data in the parallel shift register 82 to be transferred to the latch register 83, the second line data is shifted to the parallel shift register 82, and the third line data is transferred to the serial shift register 83.
1 is man-powered.

When a strobe signal set to a time width for lighting the LED is input, the LED array 73 is switched in accordance with the image data input to the latch register 83.

In this way, the lighting of the LED array 73 is controlled for each line based on the image data, and a pit image is formed on the photoreceptor.

Margin (d) Registration Control Next, the timing of registration control for transferring the electrostatic latent image formed on the photoreceptor 21 to a predetermined position on the copy paper will be explained.

During analog copying and digital copying, the data writing method is different and the exposure position is different, so the timing of registration control for transferring the image formed on the photoreceptor 21 to a predetermined position on the copy paper is different.

In the case of analog copy control (see FIG. 13), the timer value for driving the clutch 38 of the registration roller 37 (FIG. 3) is set at the leading edge of the original image or on the photoreceptor 21 in FIG. It is set so that when it rotates from the eight exposure positions to the transfer position, it coincides with the leading edge of the printing area of the paper 40 (FIG. 9). In other words, the distance Q1 from the registration roller 37 to the transfer point is subtracted from the distance 12c on the photoreceptor corresponding to the angle section C in FIG. Specifically, this is performed by starting a timer using a switch (not shown) activated by the movement of the lighting unit 3 and counting clock pulses synchronized with the movement of the lighting unit 3. .

The distance that the illumination unit 3 moves while the leading edge of the document image moves by (f2 cm (lυ), that is, the exposure point on the document moves from the operating point e of the timer start switch to the registration roller 37
Since the distance Q to be moved by the drive timing differs depending on the scanning magnification of the optical system, a timer value is calculated according to the copying magnification.

When the timer times up, the clutch 38 is driven and the paper 40 is conveyed by the registration rollers 37, but since the timing at which the paper 40 reaches the transfer point and the timing at which the leading edge of the image reaches the transfer point are the same, ,
The leading edge of the image on the transfer paper and the leading edge of the paper match.

In this embodiment, since the registration timer counts clock pulses synchronized with the movement of the illumination unit 3, it is necessary to calculate the timer value in accordance with the copying magnification. However, if the configuration is such that it is started at the moment when the leading edge of the document starts being exposed and counts clock pulses synchronized with the rotation of the photoreceptor 21, the speed of the photoreceptor is constant, so there is no need to perform correction calculations based on the scanning magnification. , start switch position variation, timing roller 37
It is only necessary to correct positional variations, etc.

On the other hand, in the case of digital copy control (see FIG. 14), a timer different from the timer used for analog copy control is started at the start of printing, as will be described later. When the timer expires, the registration roller clutch 38 is driven, and the paper 40 is conveyed by the registration rollers 37.

At this time, the timer value is the LED head 71 on the photoreceptor 21.
Counting occurs when the leading edge of the printed image moves by (f2d - 12α) from point f with respect to the distance from the printing point r to the transfer point, that is, the distance Qd on the photoreceptor corresponding to the angle section d in Fig. 8. It is set to be uploaded. Note that α is the top margin amount when the print area is set to be slightly smaller than the paper 40, as shown in FIG.

Also at this time, corrections are made for variations in the position of the print head 71, variations in the position of the registration rollers 37, and the like.

(e) Control System FIG. 1O is a control block diagram of the multifunctional copying machine of this embodiment.

Whole system controller composed of CPU
ot is an operation panel controller 105, a subsystem controller 102, an image processing processor 111. It is connected to human output interface controllers 112 and 113 via control signal communication lines 121 and 122, and performs management control of the entire system.

The subsystem controller 102 includes controllers 103, 104, 114, and 11 that control various parts within the copying machine according to commands from the overall system controller 101.
5 and reports their status to the overall system controller 101.

The mechanical controller 103 controls the area around the photoreceptor and the paper path device based on a preset control program according to commands from the subsystem controller 102, and reports the status of each part to the subsystem controller 102. For example, develop 2323
, 24, 25 are monitored by the mechanical controller +03, and transmitted to the subsystem controller 102 and further to the overall system controller 101 as a status report.

The scanning optical system controller 104 reports the control of each part of the scanning optical system and the status of each part to the subsystem controller 102 in response to a command from the subsystem controller 102 . Specifically, blinking and light amount control of the illumination lamp 4, scanning control of the illumination unit 3 and mirror unit 6,
Scanning lens lO and mirror unit based on copying magnification! -1
1 position control, scanning speed calculation, etc.

The operation panel controller 105 includes switches operated by an operator (including a mode setting switch).
etc. are reported to the overall system controller lot, and the overall system controller! According to the command 01, the lighting of various indicators is controlled.

The image sensor controller +14 controls the image sensor 61 according to a command from the subsystem controller 102.
The image processing unit 11 takes in an image signal from the computer and causes the image processing processor Ill to perform specified processing on the image signal.

The LED head controller 115 controls the image processing processor 111 according to instructions from the subsystem controller 102.
．． Alternatively, image data is taken in from the human interface controller 112 and the LED head 7! Let North write the image.

Also, based on the information from the subsystem controller 102, it performs the inversion of negative and positive, calculation of an image area corresponding to the paper size, and editing of image data based on this.

The image processing processor Ill processes the image sensor controller 1 based on the command from the overall system controller +01.
14, performs halftone processing on the image data sent from 14 using a specified dither pattern, compresses the image data, and outputs it to the output 1/F controller 113.
It is output to the ED head controller 115 and directly printed (digital copy).

It also performs restoration processing of image data taken in from the human-powered 1/F controller 112.

The output I/F controller 113 controls communication with external equipment according to commands from the overall system controller 101, and outputs image data processed by the image processing processor Ill to the external equipment.

The human power 1/F controller 112 controls communication with external equipment according to commands from the overall system controller +01, imports image data from the external equipment, and controls the LED
The captured data is sent to the image processing processor Ill in order to be converted into data in a form that can be printed by the head 71.

Control signal lines 121 and 122 connected to the overall system controller 101 are lines for communicating control commands and status status.

Signal line 1 connected to subsystem controller 102
23 is also a line for communicating control commands and status status, and includes a timing signal for defining control timing.

Signal line 13 for exchanging control signals with external equipment
1 and 132 and image signal lines 133 and 134 for transmitting and receiving image data are selected depending on the type of external device, respectively.

The image signal line 135 from the image sensor 61 and the image signal line 136 to the LED head 71 are serial data image signal lines, and the other image signal lines 137, 138, 13
9140 uses an 8-bit parallel data image signal line.

In FIG. 10, the area surrounded by the dashed line is an analog type control block based on the control block, and a multifunction copying machine is constructed by using this as it is. The operation panel controller 105 is connected to the control line 121 in an analog copying machine.
' to the subsystem controller 102.

The general nostem controller 101 can control composite printing based on the access status report of the photointerrupter switches 93 and 94 and the operation information from the operation panel controller 105. For example, computer data can be printed on paper on which an analog copy of an original image has been made.

That is, the computer data taken in from the data line 131 is printed on the photoreceptor 21 by the LED head 71, and when the registration roller clutch 38 is activated (FIG. 14), the LED is printed on the paper on which the original image has been copied.
Computer data created by the head 71 is transferred.

(f) Flow of copying FIGS. 11(a), (b), and (c) show the flow of control by the overall system controller lot.

Figure 11 (b
) step S50. S58. This will be explained in relation to S59.

When the main switch (not shown) is pressed and power is supplied (step Sl (hereinafter "step" will be omitted))
, initial settings are performed (S2), then a check of the device is performed (S3), and it is determined whether the device is normal (S4). If it is not normal, the operation panel (not shown)
An error message is displayed (S5).

If the device is normal, mode selection and condition settings corresponding to warm-up and settings on the operation panel are performed in parallel.

Warm-up (Sll) is performed until it is completed (YES in S12). Once completed, the process advances to 845 to start up the device.

On the other hand, the mode (tvl) is selected on the operation panel (S21). The modes include:
Analog copy mode CM=1), image reading mode (M=
2), image writing mode (M=3), and digital copying mode (M=4). Next, if the operating conditions of the copying machine are the same as the initial conditions for each mode (YES in S22), or if they are not the same but the conditions do not match the mode (N in S23).
o) sets initial conditions for each mode (S24)
. Then, the process advances to S41. On the other hand, if the conditions match the mode (YES in S23), the process directly proceeds to S41.

Further, conditions such as the paper feed cassette are set on the operation panel (S31). Then, it is determined whether the condition is suitable for the mode 532), and if not, a warning that the condition is inappropriate is displayed on the operation panel 533), S3
Return to 1. If it is compatible with the mode, it will advance by 84 days. The table shows the setting conditions for each mode.

In the margin table mode and setting conditions S41 below, the apparatus is set (including the settings of the developing device and transfer charger for normal development or reversal development, which is a feature of the present invention) based on the above mode/condition settings (S4
1. (See Figure 12). Then, a check is made to see if the device is normal (84, 2). If normal, proceed to S45 and start up the device. If it is not normal, an error is displayed (S44), and then S11, S21. Return to S31 and perform resetting.

When the device is started (S45), the process proceeds to FIG. 11(b), the selected mode (M) is checked, and the process branches accordingly (S46).

In the analog copying mode (M=i), first, it is determined whether or not there is toner in the selected developing device (S50).

If there is toner, then the illumination lamp 4 is controlled, the photoreceptor 21 is driven, the electrophotographic process system is controlled, the transport system is driven, and the fixing section is controlled (S51). Next, paper feeding control (S52), setting of the foldable mirror 14 and scanning of the optical system (S53), and control of the registration roller 37 (S54)
, see Figure 13) and optical system return (S55),
As long as the operation is normal (YES at 856), until the end (S
57: YES), and after finishing, Sll, S2
1. Return to S31. If the operation is not normal (N at 856)
o), After displaying the error (S44), SIl, S2i,
Return to S31.

If copying is completed (YES in S57), press S.
I l, S21. Proceed to S31.

If it is determined in S50 that there is no toner, regular development (analog copying) cannot be performed. However, since this copying machine is capable of digital copying, even if analog copying becomes impossible due to a trouble, the mode is switched to digital copying (M=4) without stopping the copying machine (S58). Then, in conjunction with this mode switching, device setting (S59, see FIG. 12) is performed. Therefore, after switching the mode, the mirror 14 is retracted and the image sensor 61 reads the original image.
An image is written on the photoreceptor 21 by the LED head 71, and development is performed by the developer 24 using a reversal development method. This allows digital copying to be performed without stopping the copying machine even when regular development is not possible, thereby avoiding machine downtime. In particular, if the toner color remains the same even after switching modes, it is more convenient to continue copying.

Note that when switching the mode, a warning may be displayed and the user may decide whether to switch or not.

Furthermore, if regular development is not possible due to other problems other than toner empty, it is possible to switch to digital copying in the same way.

In the image reading mode (M=2), communication is performed with an external device (such as a post computer) (S61), and upon receiving a signal to start image reading, the illumination lamp 4 is controlled (S6
2) Initialize the reading circuit (S63). Then, the foldable mirror 14 is retracted, the scanning optical system scans the document (S64), the image sensor 61 reads the image, processes the image, and outputs data to an external device (S65).

When image reading is completed, a completion signal is sent to the external device (
S66), and the illumination unit 3 and mirror unit 6 of the scanning optical system are returned to their original positions (S67).

Next, it is determined whether the image reading has been completed normally (S6
8). If it ends normally, Sll, S21, S31
Return to If it has not ended normally, an error is displayed (S44), Sll, S21. Return to S31.

In the image writing mode (M=3), as shown in FIG. 11(c), the photoreceptor 21 is driven, the electrophotographic process system is controlled, the transport system is driven, and the fixing section is controlled (S71). Communicate with external equipment (host computer, etc.) (S72
), receives a signal to start image writing.

Next, paper feed control (873), image digital input from external equipment, image data processing, and control of the print head 71 (S
74), controls the registration roller 37 (S75, see FIG. 14).

Next, it is determined whether the image writing operation is normal (S7
6). If it is not normal, an error is displayed (S44)
, S 11. S21. Return to S31. If normal, next, communication is performed with the external device (S77).

Then, it is determined whether or not image writing is completed (878).
. If it is not completed, the process returns to S73 and writing is performed again. If finished, S11. Return to S21,931.

In the digital copying mode (M=4), first, the illumination lamp 4 is controlled, the photosensitive drum 21 is driven, the electrophotographic process section is controlled, the transport system is driven, and the fixing section is controlled (S
81). Next, the paper feed is controlled (S82), the foldable mirror 14 is retracted, the scanning optical system scans the document (S83), the image is read by the image sensor 61, the image data is processed, and the print head 71 (S84), and controls the registration rollers 37 to feed the paper (S85, see FIG. 14). If the scanning is completed, the scanning optical system is returned to its original position (986). Next, it is determined whether the digital copying operation is normal (S87).

If it is not normal, after displaying an error message (S44),
l l, S21. Return to S31. If normal, then
It is determined whether the digital copying is finished (S8B). If it is not completed, the process returns to S82 and the copying operation continues. If it is finished, step S11. S21° Return to S31.

FIG. 12 shows control regarding the developing device and transfer charger in the above device set (S41, 559). First, the process branches depending on the mode (M) (S101). M=1
In the case of (analog copying mode), either one of the developing devices 23 and 25 for regular development is set to a developing state. That is, in response to the determination as to whether black-and-white development is required (S102), if black-and-white development is required, the developing device 25 for black toner is set (at 81° C. 3); if not (color copying), the developing device 25 for red toner is set. 23 to a developable state (S1
04). Then, the transfer charger 26 is set to negative polarity (
S l 05).

In addition, in the case of M=2 (image reading mode) and M-4 (digital copying mode), reversal development is performed, so set the reversal developing device 24 to a developing state (5llll) and transfer charger 26. Make it positive polarity (S I I 2).

FIG. 13 shows the flow of registration control (S54) in analog copy mode. First, the timer value for driving the electromagnetic clutch 38 (already explained using FIG. 8) is calculated (S I 2I), and the timer is started (S I 22). When the timer is counted up (S124: YES), the clutch 38 is driven (S123).
I25), the paper is transported.

Further, FIG. 14 shows the flow of registration control in the digital copy mode (S85) and the image write mode (S75). After waiting for the start of printing (YES in S141), another timer value as already explained using FIG. 8 is set, and timer timing is performed (S142). Then, when the timer counts up (YES at S l 43)
), the clutch 38 is driven (S144), and the paper is conveyed.

The following margins (effects of the invention) When the developing device that should be used in analog copying mode cannot be used due to some kind of trouble (including toner empty), it is set to digital copying mode, so copying can be continued without machine failure. .

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a multifunction copying machine. FIG. 2 is a perspective view of the developing device. FIG. 3 is a perspective view of the registration roller. FIG. 4 is a perspective view of the COD image sensor. FIG. 5 is a block diagram of the image reading circuit. FIG. 6 is a perspective view of the LED head. FIG. 7 is a circuit diagram of the LED head. FIG. 8 is a diagram for explaining the timing of registration control. FIG. 9 is a diagram showing the meaning of α. FIG. 1O is a block diagram of the control system of the multifunctional copying machine. Figure 11 (a), (b), (c), Figure 12,
13 and 114 are flowcharts of the control of the overall system controller. l...Multifunction copying machine, 14...Foldable reflecting mirror 21...Photoconductor, 23.25...Positively charged toner developing device, 24...Negatively charged toner developing device, 26... - Transfer charger, 61... COD image sensor, 71... LED head, 101... Overall system controller. M3 Figure Patent Applicant Minolta Camera Co., Ltd. Agent Patent Attorney Haka Aoyama Figure 7 Figure 11 Figure (b) Figure (C) Figure Figure Figure

Claims (1)

[Claims] (1) A photoconductor on which an electrostatic latent image of the document is formed, an optical system that projects the document image on the document table onto the photoconductor, and an optical path that passes through a common optical path to the vicinity of the photoconductor. an image sensor means on which an original image is projected; an image writing head for projecting a dot-shaped optical image onto a photoreceptor in response to an electric signal of the original image read by the image sensor means; A first developer uses a regular development method in which unexposed areas are made visible with toner, a second developer uses a reversal development method in which exposed areas of the photoreceptor are made visible with toner, and a toner image is transferred to paper by applying a voltage. a transfer device for transferring; a selection means for selecting an analog copy mode using a first developing device; and a digital copy mode using an image sensor, an image writing head, and a second developing device; and an analog copy mode and a digital copy mode by the selection means. and a copying control means for operating the first developing device and the second developing device and setting the polarity of the voltage of the transfer device in response to the selection of the first developing device and the second developing device, respectively, and for setting the polarity of the voltage of the transfer device.
A multifunctional copying machine characterized by switching copying condition settings to support a digital copying mode when a developing device cannot be used.