JP3099347B2 - Imaging device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having an intermediate transfer medium for secondary-transferring a toner image transferred from a photoconductor to recording paper.

[Conventional technology]

The electrophotographic process is a charging process for uniformly charging the surface of the photoreceptor, an exposure process for forming a latent image according to image information by partially erasing the charged charge by irradiating the photoreceptor with light, A developing process of forming a toner image by attaching toner in a developer to a latent image, a transferring process of transferring a toner image from a toner image carrier to a recording sheet (hereinafter referred to as “sheet”), and a toner transferred to the sheet It consists of a fixing process for fixing an image, and is widely used as a method for forming a hard copy image.

As a transfer method, there is an intermediate transfer method in which a toner image is primarily transferred from a photoconductor to an intermediate transfer medium rotating at the same peripheral speed as the photoconductor, and then the toner image is secondarily transferred to a sheet.

In general, a copying machine that forms a copy image has a paper storage unit that stores a large number of sheets, and is configured to be capable of automatically feeding paper from the paper storage unit.

Examples of the paper storage means include a detachable paper cassette and a hopper type paper unit including a lift mechanism that moves up and down in accordance with paper feeding. Usually, the paper storage means is used to detect a paper shortage (empty). A sensor is provided.

In addition, a conveyance path from a paper feeding means (paper feed port) to a discharge port for discharging a sheet after forming a copy image,
A jam sensor for detecting a paper jam (paper jam) is provided at an appropriate position.

[Problems to be solved by the invention]

Normally, if the paper in the paper storage means is insufficient before pressing the print key for starting the image formation, the image formation using the paper storage means is prohibited. However, for example, in so-called multi-copy (continuous copying) in which a plurality of copied images are formed on the same document, paper is present at the start of image formation, but is used for image formation on a plurality of sheets after the start of image formation. Paper to be used may be insufficient.

Also, a jam may occur after the start of image formation and before the secondary transfer.

In such a case, in the conventional copying machine, the image formation is stopped when a paper shortage is detected or when the occurrence of a jam is detected, and the state of each part performing the electrophotographic process is determined by pressing the print key. It returns to the standby state before the start of image formation.

That is, even if a toner image has already been formed on the intermediate transfer medium, the toner image is removed by the cleaning unit.

For this reason, conventionally, when the paper in the paper storage unit becomes insufficient during image formation, or when a paper jam occurs, the toner removed without being transferred to the paper and the image formation required from the start to the stop of the image formation. There is a problem that the image time is wasted.

In particular, in the formation of a color copy image in which three primary color toner images of cyan (C), magenta (M), and yellow (Y) are superimposed, the image is formed at the stage when two or three color toner images are formed. In the case where the image formation is stopped, the amount of waste toner is larger than in the case where the image formation of a monocolor copy image using the single color toner is stopped.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above circumstances, and has as its object to prevent wasteful consumption of toner when recording paper is insufficient or when a paper jam occurs.

[Means for solving the problem]

In order to solve the above-mentioned problem, an image forming apparatus according to the first aspect of the present invention is an image forming apparatus that forms an image on recording paper by an image forming process by electrophotography, wherein a toner image is formed on a surface. A photoreceptor, an intermediate transfer medium for secondarily transferring a toner image primarily transferred from the photoreceptor to recording paper, paper empty detection means for detecting the presence or absence of recording paper, and after the start of the image forming process And when the paper empty detecting means detects the deficiency of the recording paper before the completion of the primary transfer, the primary transfer is completed and the toner image is held on the intermediate transfer medium to form an image. The image forming apparatus includes image forming interrupting means for interrupting the process, and image forming continuing means for continuing the image forming process interrupted by the image forming interrupting means when the recording paper is supplied.

An image forming apparatus according to a second aspect of the present invention includes a jam detecting unit that detects a jam of the recording sheet, and the jam detecting unit detects the jam of the recording sheet after the start of the image forming process and before the completion of the primary transfer. When a jam is detected,
An image forming interrupting unit that completes the next transfer and holds the toner image on the intermediate transfer medium to interrupt the image forming process; and the image forming interrupting unit is interrupted when the jam of the recording paper is eliminated. Image forming continuation means for continuing the image forming process.

The copying machine according to claim 3, wherein when the jam detecting unit detects a jam of the recording sheet during the transfer of the toner image from the intermediate transfer medium, the image forming interrupting unit shifts to the intermediate transfer medium. Image forming stopping means for stopping the image forming process in place of holding the toner image.

(Operation)

The paper empty detection means detects the presence or absence of a recording sheet.

 The jam detecting means detects a jam of the recording paper.

The image forming interrupting means is provided after the start of the image forming process and before the completion of the primary transfer, when the paper empty detecting means detects the shortage of the recording paper during the image forming of the copied image, or the jam detecting means detects the copy image. After the primary transfer is completed when the jam of the recording paper is detected during the image formation of
The image forming process is interrupted by holding the toner image on the intermediate transfer medium.

The image forming continuation means continues the image forming process interrupted by the image forming interrupting means when the recording paper is supplied or when the jam of the recording paper is eliminated.

The image forming suspending unit is configured to perform image forming instead of holding the toner image on the intermediate transfer medium by the image forming suspending unit when the jam detecting unit detects the jam of the recording paper during the transfer of the toner image from the intermediate transfer medium. Abort the process.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional front view showing a schematic configuration of the copying machine 1. As shown in FIG.

A photosensitive drum 3 is disposed at a slightly upper left portion of the center of the copying machine 1 so as to be rotatable in a clockwise direction (direction of an arrow M1). Around the photosensitive drum 3, a charging charger 4, an editing eraser 5, and a developing device 6 are provided. -9, transfer belt 1 as intermediate transfer medium
1, a cleaning device 22 and a main eraser 23 are provided.

The photoreceptor drum 3 has a photoreceptor layer provided on the surface thereof. The surface of the photoreceptor drum 3 is uniformly charged by passing through a main eraser 23 and a charging charger 4. Receive exposure.

The editing eraser 5 is composed of an LED array in which a number of LEDs are arranged in a row in a holder arranged along the axial direction of the photosensitive drum 3 so that a latent image on the photosensitive drum 3 can be partially erased. It is configured. The lighting timing of each LED is controlled by the image processing unit 100.

In each of the developing units 6, 7, 8, and 9, a developer in which toner of each color of yellow (Y), magenta (M), cyan (C), and black (BK) is mixed with a carrier for triboelectric charging is used. Toner density sensors (ATDC sensors) 71y, 71m, 71c and 71k are provided for controlling the density of the toners of the respective colors. The copying machine 1 is located above the developing device 6.
There is provided a humidity sensor 70 for detecting the humidity inside.

The developing units 6 to 9 are not limited to the type in which the developing units 6 to 9 are fixedly arranged around the photosensitive drum 3, but are, for example, a type in which the developing units 6 to 9 are integrated to be movable in the vertical direction. Alternatively, any material that can selectively supply different colors of toner to the photosensitive drum 3 may be used.

The transfer belt 11 temporarily holds the toner image developed on the photosensitive drum 3 by the developing devices 6 to 9 so as to transfer (secondarily transfer) the toner image onto the paper P, and includes a plurality of rollers.
It is supported on the photosensitive drum 3 so as to be rotatable in the counterclockwise direction (the direction of arrow M4) while constantly contacting the photosensitive drum 3.

A transfer charger 17 for primary transfer of a toner image from the photosensitive drum 3 onto the transfer belt 11 is disposed inside the transfer belt 11, and a transfer charger for secondary transfer is provided outside the transfer belt 11. 20, a separation charger 21 for separating the paper P from the transfer belt 11, and a belt cleaner 19 having a fur brush 190 for cleaning the outer surface of the transfer belt 11 are provided.

Further, between the rollers 15 and 16, and between the rollers 12 and 13, belt mark sensors 72 and 72s for detecting the position of the transfer belt 11 are fixedly arranged.

A document table gas 28 is arranged on the upper surface of the copying machine 1.
A document size detecting device 101 that moves so as not to hinder the scanning and detects the size of the document D is built in the back side immediately below the platen gas 28.

An optical system 27 is disposed above the copying machine 1. The optical system 27 has a scanner 30 reciprocally movable in the direction of arrow M5 (forward direction) and the direction of arrow M6 (backward direction) below the platen glass 28, and the position is adjusted in accordance with the copy magnification. Lens 35, filter selection device for color separation exposure
36, a fixed mirror 37 for guiding the scanning light L reflected by the mirror attached to the filter selecting device 36 to the photosensitive drum 3,
And a color image sensor 38 that receives the scanning light L transmitted through the mirror of the filter selection device 36, and the like.
When the scanner 30 moves forward, the original D is scanned and the photosensitive drum 3 is scanned.
Is exposed.

The scanner 30 includes a first slider 31 having an exposure lamp 33 and a mirror 34, and a second slider 32 having mirrors 35a and 35b.
When scanning the original D, the first slider 31
Moves forward at a speed of v / n (n is a copy magnification) with respect to the peripheral speed v of the photosensitive drum 3, and the second slider 32 moves forward at a speed of v / 2n. Driven by a scan motor. Completion of the return of the scanner 30, that is, the scanner 30
Is returned to the reference position (home position) by a scanner home switch 74 including a photo sensor.

The filter selecting device 36 includes a half mirror 36ND (transmission / reflection ratio is 6: 4) and three filter mirrors 36YB, 36MG, 36CR radially at an angle of 90 degrees with respect to the axis 36a. Provided and rotated, one of these mirrors is selectively switched. The filter mirrors 36YB, 36MG, and 36CR integrate the mirror and the filter by depositing blue (B), green (G), and red (R) color separation filters on the mirror surface, respectively. , M, and C are used in correspondence with the toner of each color.

In the exposure scanning for forming an image, the reflection surface of the selected mirror is positioned so as to be inclined about 10 degrees clockwise with respect to the vertical plane.
Exposure point. Further, in the preliminary scanning for reading the image of the original D, the half mirror 36ND is selected, and in order to improve the MTF (imaging power) of the color image sensor 38, the half mirror 36ND is positioned so as to be orthogonal to the incident direction of the scanning light L. Is done. Reference numeral 77 denotes a rotational position detecting sensor for determining the home position of the filter selecting device 36. FIG. 1 shows a state where the filter mirror 36CR is selected and positioned.

In the following description, the half mirror 36ND and the filter mirrors 36YB, 36MG, 36CR are respectively set based on the color separation characteristics.
There are also ND filters, B filters, G filters, and R filters.

On the other hand, an upper paper cassette 42 and a lower paper cassette 43 containing a large number of papers P are mounted in the lower part of the copying machine 1, and the paper P is manually fed to the left side of the copying machine 1. A manual paper feed port 41 is provided. The manual feed port 41 is opened by opening the door 41a. The paper cassette 42, the paper cassette 43, and the manual paper feed port 41 are used alternatively when feeding paper.

The paper cassettes 42 and 43 include pickup rollers 44 and 45 for feeding out the paper P one by one, paper size sensors 81 and 82 for detecting the size of the paper P, and a paper P, respectively.
Empty sensor 8 for detecting deficiency
3, 84 are provided. The manual paper feed port 41 is provided with a manual feed sensor 87 for detecting insertion of the paper P.

The paper P fed from the paper cassette 42 is conveyed to the timing roller 46 by the paper feed roller 4, and the paper P fed from the paper cassette 43 is fed by the paper feed rollers 48 and 47.
Is transported to the timing roller 46, where it stands by. The paper P inserted in the manual paper feed port 41 is conveyed by the manual feed roller 49 to the timing roller 46.

In the vicinity of the paper feed roller 47, a paper detection sensor 85 for detecting the presence or absence of the paper P in the paper feed path R1 between the paper feed roller 47 and the timing roller 46 is provided. A timing sensor 86 for detecting the position of the leading edge of the sheet P is provided.

The waiting sheet P is conveyed in synchronization with the transfer belt 11 by the rotation of the timing roller 46, and the toner image is secondarily transferred from the transfer belt 11 to the sheet P at the transfer position. After that, the paper P is fixed by the conveyance unit 50 having a linear distance corresponding to the A4 size paper.
Sent to

The fixing unit 51 includes an upper roller 52 having heater lamps 54 and 55 and a lower roller 53 having heater lamp 56.
And fuses the toner image to fix it on the paper P. Temperature sensors 91 and 92 each composed of a thermistor are provided near each of the rollers 52 and 53, respectively.

The sheet P on which a desired copy image is formed by fixing the toner image is discharged from a discharge roller 57 having a discharge sensor 88 disposed in the vicinity.
Is sent out to the sorter 2 and discharged to the storage tray 61 of the sorter 2 or the sorting bean (shelf) 62.

Further, in the copying machine 1 of the present embodiment, a return device 60 for re-fixing which is used at the time of image formation in the OHP mode for forming a copy image for an overhead projector is mounted. The returning device 60 is for transporting the paper P that has passed through the fixing unit 51 so as to return to the entrance of the fixing unit 51 (on the side of the transport belt 50), and from the discharge side (exit) of the fixing unit 51 as described above. A transport mechanism 58 having a return path R2 through the timing roller 46, and a switching claw 59 for switching the transport direction of the paper P sent from the fixing unit 51 to the discharge roller 57 side or the return path R2 side. ing. The switching claw 59 is driven by a solenoid (not shown),
A return paper detection sensor 89 for detecting the presence or absence of the paper P in the return path R2 is disposed near 59.

In FIG. 1, reference numeral 24 denotes a main motor which mainly drives the units related to paper feeding and conveyance of the paper P, and reference numeral 25 denotes a drive which drives the photosensitive drum 3 and the transfer belt 11.
The PC motor 26 is a cooling fan.

In the copying machine 1 configured as described above, the above-described Y, M, C
And BK monocolor copy images of each single toner color, Y, M, C
R (Y and M), G (Y and C), B (M and C) composite monocolor copied image obtained by superimposing two toner images of the three primary colors, and three primary color toners It is possible to form a color copy image obtained by superimposing images.

In the formation of a monocolor copy image of a single toner color (monocolor mode), exposure scanning of the original D is performed using the half mirror 36ND, and the latent image formed on the photosensitive drum 3 is changed to a designated color. Any one of the developing units 6 to 9
The toner image is transferred to the transfer belt 11 by developing the toner image on the transfer belt 11.

In forming a composite monocolor copy image, the same original D is subjected to exposure scanning twice using the half mirror 36ND, and two color toner images are superimposed on the transfer belt 11.

In forming a color copy image (full color mode), Y, M, and C toners are used in order. That is, a total of three exposure scans are performed on the same original D, and the B, G, and R filters and developing devices 6 to 8 are selectively switched for each scan, and a latent image obtained by color separation of the original D is performed. Is formed and developed, and the toner image is sequentially transferred to the transfer belt 11, and the transfer belt
11 superimpose toner images of each color.

In superposing toner images (hereinafter referred to as “multiple transfer”), it is necessary to transfer each toner image to the same position on the transfer belt 11. A signal from the belt mark sensor 72 or 72 s that has detected the belt mark provided at the position earlier is defined as a belt mark signal S10, and the start timing of the movement of the scanner 30 based on the generation timing of the belt mark signal S10, that is, the photosensitive drum The start timing of the formation of the latent image in Step 3 is controlled.

FIG. 2 is a plan view of the operation panel OP provided on the upper surface of the copying machine 1.

On the right side of the operation panel OP, a key 250 for specifying an automatic paper selection mode and its display LED 252, a key 251 for specifying an automatic magnification selection mode and its display LED 253, a print key 200 for starting a copying operation, and a copy are provided. LED 200a that lights in green when possible, numeric keypad 202 for setting copy conditions such as the number of copies, 7-segment LED 201 for displaying the number of copies, clear / stop key 203, interrupt key 204, and setting for copy magnification Magnification up / down keys 205 and 206, 3-digit 7-segment LED 207 for displaying the copy magnification, up key 210 and down key 208 for manually setting the density of the copy image step by step, and LED 211 for displaying the density level of the copy image , An auto-density setting key 209, an auto-density display LED 222, and other keys and display LEDs used in a normal copying operation.

Also, on the left side of the operation panel OP, LEDs 223Y, 223M, 223C, 223K for indicating the shortage of the toner of each color of Y, M, C, BK, LED 224a for indicating that the storage container for the waste toner is full, and an interrupt display LED 224b. Key 225-23 corresponding to each color (Y, M, C, R, G, B, BK) for specifying the color of a mono-color copy image.
1, full color 232 for specifying color copying, OHP key 233 for selecting the OHP mode, book key 234 used when copying the left and right pages of a spread such as a book into two sheets of paper P, Display LEDs 235 to 244 corresponding to the respective keys 225 to 234, paper selection keys 245 and 246, LEDs 247 and 248 for displaying the selected paper cassettes 42 and 43, and lack of paper P in the selected paper cassettes 42 and 43. Is displayed. A paper empty LED 249 is displayed.

 FIG. 3 is a block diagram of the control unit 400 of the copying machine 1.

The control unit 400 is a CPU that controls the entire operation of the copying machine 1.
(Central processing unit) A scan motor controller 402 for controlling the driving of the scanner 30 with a focus on the 401, a lens motor controller 403 for controlling the movement of the main lens 35 according to the copy magnification, and a filter for controlling the driving of the filter selecting device 36. It comprises a mirror motor controller 404, a charging charger controller 405, an exposure lamp controller 406, and the like.

The CPU 401 has an operation panel OP along with each controller.
A switch matrix 451 and display matrices 452, 7 in which the above operation keys and various display LEDs are arranged vertically and horizontally, respectively.
The segment LEDs 201 and 207, the decoder 453 corresponding to the switch matrix 451, and the drivers 454 and 455 that supply lighting power to each display LED are connected.

The CPU 401 also provides the image processing unit 100 that performs signal processing of the photoelectric conversion device S0 of the color image sensor 83, and the size and placement direction of the original D (vertical or vertical) based on a combination of the outputs of the plurality of reflective photosensors. A document size detection device 101 using a known detection method for determining landscape is connected.

Further, the analog input port and the digital input port of the CPU 401 receive the output signals of the sensors arranged in the respective sections of the copying machine 1, the signals from the respective sensors and the switch matrix 451, and the image processing section 100 and the document. Based on data from the size detection device 101, ON / OFF of each part such as the motors 24 and 25 connected to the output port, various clutches such as a developing clutch, and each charger, or control of an operation level is performed.

The CPU 401 has a built-in nonvolatile memory for storing management data such as the cumulative number of copies and the number of occurrences of jams.

 FIG. 15 is a front sectional view of the belt cleaner 19.

The belt cleaner 19 is a roller that supports the transfer belt 11.
Cylindrical fur brush 19 arranged opposite to 15
0, a collecting roller 191 for collecting toner scraped from the transfer belt 11 by the fur brush 190, a blade 192 for removing toner attached to the surface of the collecting roller 191, and an exterior support 193 supporting these members. The fur brush 1 is configured and rotated about the support shaft 194.
The fur brush 190 and the transfer belt 11 are provided so as to be movable to an operating position where the transfer belt 90 contacts the transfer belt 11 and a retracted position where the fur brush 190 and the transfer belt 11 are separated by a predetermined distance.

FIG. 15 shows a state in which the belt cleaner 19 is at the operating position, and when the belt cleaner 19 has moved to the retracted position, it is in the state shown by the one-dot chain line in the figure.

The mechanism for moving the belt cleaner 19 includes a disc-shaped eccentric cam 196 attached to the rotating shaft 196a, an ankle lever 198 for stopping the rotation of the rotating shaft 196a about every 180 degrees, and a solenoid 195 for rotating the ankle lever 198. , Belt cleaner
A spring 199 biases the transfer shaft 11 toward the transfer belt 11 and a mechanical clutch (not shown) biases the rotation shaft 196a to rotate in the direction of arrow M9.

The uncle lever 198 is provided with a stop claw and a stop head (not shown) at its tip.
The rotation of the rotating shaft 196a causes the protrusion (not shown) provided on the rotating shaft 196a to alternately contact the stopping claw or the stopping head.
The rotation of the rotation shaft 196a positions the rotation shaft 196a every 180 degrees.

The solenoid 195 is turned on and off by a drive unit 195a controlled by a drive control signal S9 output from the CPU 401 described above. Further, the solenoid 195 is provided with a temperature sensor 75 for detecting the temperature, and an output signal S7 of the temperature sensor is sent to the CPU 401.

When the solenoid 195 is in the off state, the belt cleaner 19 is in the operating state. At this time, the eccentric cam 196 is in the state shown in the figure, and the roller 197 rotatably fixed to the upper part of the exterior support 193 and the eccentric cam 196 abut, so that the fur brush 190 is appropriately pressed against the transfer belt 11. The belt cleaner 19 is positioned so as to perform the operation.

The drive control signal S9 is added to the drive unit 195a, and the solenoid is
When the rod 195 is turned on and the rod 195b moves downward against the urging force of the spring 198a, the ankle lever 198 moves
The rotation of the rotation shaft 196a by the stop claw or the stop head (not shown) is switched around the center 98b. As a result, the rotation shaft 196a makes a half turn, the eccentric cam 196 pushes the roller 197 against the urging force of the spring 199, and the belt cleaner 19 moves to the retracted position.

To remove the toner remaining on the surface of the transfer belt 11, that is, to clean the transfer belt 11, the belt cleaner 19 is moved to the operating position to bring the fur brush 190 into contact with the transfer belt 11, and the fur brush 190 is moved by a cleaner charger (not shown). Further, the fur brush 190 and the collection roller 191 are rotated while a high voltage HV (cleaner bias HV) for charging is applied to the collection roller 191. As a result, the toner on the transfer belt 11 is scraped off by the fur brush 190, and is electrostatically attracted to the charged fur brush 190. Since the cleaner bias HV is set so that the charge amount of the collection roller 191 is larger than the charge amount of the fur brush 190, the toner adsorbed on the fur brush 190 moves to the collection roller 191 having a large suction force. Collection roller 1
The toner adsorbed on 91 is scraped off from collecting roller 191 by blade 192, and stored in a waste toner bottle (not shown).

In the following description, moving the belt cleaner 19 to the operating position by turning off the solenoid 195 is referred to as “pressing the fur brush 190”, and conversely, turning on the solenoid 195 moves the belt cleaner 19 to the retracted position. To move the fur brush 190
That. The application of the cleaner bias HV to the fur brush 190 and the collection roller 191 is referred to as “cleaner bias HV”.
Stopping the application of the cleaner bias HV is referred to as “turning on the HV” and “turning off the cleaner bias HV”.

Next, the operation of the copying machine 1 will be described with reference to a flowchart.

FIG. 4 is a main flowchart schematically showing the operation of the CPU 401.

When the power is turned on and the program starts, first, initialize the registers and peripheral interfaces,
An internal timer for setting the length of one routine of the CPU 401 is set (step # 1 and step # 2).

Subsequently, an image forming process related to the electrophotographic process, a scanning process for scanning the document D, a belt mark detecting process for determining a timing of the multiple transfer, a cleaning process for cleaning the transfer belt 11, Paper feed processing for controlling paper feed and conveyance, jam detection processing for paper P jam (paper jam), paper cassettes 42 and 43
Paper shortage detection processing for detecting the presence or absence of paper P in the above, image formation restart processing for restarting the image formation process interrupted by paper P shortage or jam occurrence, and reception of signals from the operation panel OP and sensors of each unit (Step 3 to Step 3)
11).

After executing the above processing, the internal timer is waited for (step # 12), and the process returns to step # 2. As a result, while the length of one routine is kept constant and the power is turned on, each processing of steps # 2 to # 12 is repeated.

Hereinafter, each process of FIG. 4 (steps # 3 to # 1)
0) will be described in order.

 FIG. 5 is a flowchart of the image forming process of FIG.

In this routine, first, the image forming state indicated by the count value of the start counter is checked (step # 20), and the following processing is executed according to each state.

In the initial state immediately after the power is turned on and in the standby state after the end of the copying operation, the state is “0”.

In state “0”, the printer waits for the print key 200 to be pressed (turned on).
While the light is on, turning on the print key 200 is invalidated (step # 21, step # 22).

When there is a sheet P in the sheet cassette 42 or 43 specified by the sheet selection keys 245 and 246, the main motor 24 and the PC motor 25 are turned on in response to the turning on of the print key 200, and the rotation of each part such as the photosensitive drum 3 is performed. Start driving.
Then, a predetermined timer value is set to a motor rise timer composed of a counter for waiting for the rotation of each motor 24, 25 to stabilize (step # 23, step # 24).

In state "1", the motor start-up timer is updated (counted up) in step # 31, thereby measuring the motor start-up time.

When the motor start-up timer is updated a number of times corresponding to the timer value and the time count ends, a paper feed permission flag for checking whether or not the conveyance of the paper P can be started in the paper feed process is set (step # 32, step # 32). # 3
3).

In state "2", whether the copy mode (copy mode) is the mono-color mode or the full-color mode specified by the operation panel OP is checked (step # 41). As a result, the processing corresponding to each copy mode is executed thereafter.

That is, among the subsequent processing, the steps # 42 to # 46 of the state "2", the states "3", "4", and the states "13" to "15" correspond to the mono color mode. Also, step # 47 to step # 49 of state “2”, state “5” to state “1”
"5" corresponds to the full color mode.

Therefore, the processing in the mono color mode will be described first.

In the case of the mono color mode, in the state “2”, the setting of the ND filter, the turning on of the charging charger 4 and the exposure lamp 33, the scan request (set of the scan request flag), and the reproduction color designated by the color keys 225 to 231 Are turned on sequentially (one of the developing units 6 to 9).

In response to this scan request, the scanner 30 starts moving forward in the scanning process, and the formation of a latent image starts.

In the state "3", the charging charger 4 and the exposure lamp 33 are turned off after the scanning of the document D is completed, and the developing device in operation is turned off (step #).
51 to Step # 53).

Then, if the image formation suspension flag is in the reset state, the process proceeds to the process of state “4” (step # 54, step # 54).
58).

On the other hand, when the imaging suspension flag is set, the state “4” is set as the state to be executed when the imaging process interrupted by the state “14” described later is restarted by the state “15”. It is set (step # 55).

Then, in order to hold the toner image already formed at the present time on the transfer belt 11, an image holding timer for measuring the time from the present time until the completion of the primary transfer is set, and then the process proceeds to the state "14". (Step # 56, Step # 57).

In state "4", it is checked whether or not there is a next copy request, that is, whether or not the image formation for the designated number of copies has been completed (step # 61).

If the number of images has not reached the designated number, normally, the process returns to the state “2” and a series of image forming processes is repeated (step # 62, step # 63).

However, when the stop flag is set, the image formation is performed by switching the selection of the paper cassettes 42 and 43. In this case, in order to shift to the standby state, the stop flag and the paper supply permission After resetting the flag, the process proceeds to state “13” (step # 62, steps # 64 to # 66).

In the state "13", the discharge sensor 88 determines whether or not the discharge of the last sheet P of the designated number of copies or the sheet P used by repeating the feed selection during copying is completed.
(Step # 141).

When the discharge is completed, the main motor 24 and the PC motor 25 are turned off (step # 142), and the state is returned to the initial value "0" in order to put the copying machine 1 in a standby state.

If the ejection has not been completed, the print key 200 that is turned on at the time of completion of the secondary transfer is checked, and if turned on, the state is returned to “2” (step # 144, Step # 145).

The state “14” and the state “15” perform processing for interrupting and restarting the image forming process.

That is, in the state “14”, the fur brush 190 is evacuated after the end of the time of the image holding timer, and the cleaner state in the cleaning process is set to “9”. (Steps # 151 to # 157).

By retreating the fur brush 190, the toner image is held on the transfer belt, and the transfer belt 11 stops rotating when the PC motor 25 is turned off.

In the state "15", the process waits until the image formation interruption flag is reset by the image formation restart processing, and returns to the state stored as the state at the time of image formation restart (step # 158, step # 159).

 Next, the processing in the full color mode will be described.

In the case of the full color mode, in the state "2", first, a B filter for performing color separation exposure corresponding to the Y toner is set (step # 47).

Next, a count value corresponding to the pre-processing time Tf is set in a pre-processing timer in order to set a time for cleaning (pre-cleaning) of the transfer belt 11 to be performed as pre-processing of image formation. The pre-processing time Tf at this time is defined as the pre-processing specified time required for cleaning the entire circumference of the transfer belt 11 (the time of one rotation or more of the transfer belt 11) to the actual post-cleaning being performed as the post-processing of the previous image formation. Is the remaining time after subtracting the execution time (post-processing execution time) (step # 48).

In state "5", a flag for permitting mark detection is set after completion of the pre-cleaning (steps # 71 to # 73).

With this mark detection permission, in the belt mark detection process, monitoring of the belt mark signal S10 is started to control the timing of the multiple transfer. Further, upon receiving a scan permission given by the belt mark detection process, the scan is started in synchronization with the belt mark signal S10 in the scan process.

In state "6", the developing device 6 is turned on in synchronization with the start of scanning (step # 75, step # 76).

In the state "7", first, the end of the scan is waited, the exposure lamp 33 and the charger 4 are turned off, and the developing device 6 is turned off. Then, the G filter is set in preparation for the next exposure (steps # 81 to # 81). Step # 84).

Then, the operation interruption flag is checked. If the flag is set, the mark detection permission flag is reset, the state at the time of resuming the image formation is set to “8”, the image hold timer is set, and the mono color mode is set. Then, the process proceeds to the processing of the state "14" (step # 85 to step # 89).

Hereinafter, in the state “8” and the state “9”, the state “10” and the state “11”, a series of processes for forming the M and C toner images, that is, the state “6” and the state “ 7 ", the corresponding developing device 7,
8, the exposure lamp 33 and the charging charger 4 are turned off at the end of the scan, the state when the image formation is resumed when the image formation interruption flag is set, and the image hold timer are set.

In the state "12", the presence or absence of the next copy request is checked, and if there is no next copy request, the sheet supply permission flag and the mark detection permission flag are reset, and the process proceeds to the state "13" to complete the image forming process (Step # 13)
1 to Step # 134).

When there is a next copy request, normally, after setting the B filter, the process returns to the state “6” and the image formation of each of the Y, M, and C toner images is repeated (steps # 135 to # 13).
7).

However, when the stop flag is set, as in the case of the monochrome mode, the stop flag, the sheet supply permission flag, and the mark detection permission flag are reset, and then the state “13” is set. (Step # 135, Step # 138, Step # 132 to Step # 134).

FIG. 6 is a flowchart of the scan processing of FIG.

First, the scan state is checked (step # 200), and the following processing is executed according to each state.

In the state "0", first, the presence or absence of a scan request is checked by the scan request flag (step # 20).
1). As described above, the scan request flag is set in the case of the mono color mode in the image forming processing.

If there is a scan request, the scanner 30 immediately starts the forward movement via the scan motor controller 404 (step # 202). Then, the process proceeds to the state “2” (step # 203).

If there is no scan request, the presence / absence of scan permission is checked based on the scan permission flag (step # 204). The scan permission flag is set by the belt mark detection processing in the case of the full color mode.

If the scan is permitted, the process proceeds to the next state “1” (step # 205).

In the state “1”, the forward movement of the scanner 30 is started at the output timing of the belt mark signal S10 (step # 212).

In state "2", it is checked whether or not the scanner 30 moving forward has reached the rear end of the document D and the scanning has been completed (step # 215).

Upon completion of the scanning, the return of the scanner 30 is started immediately (step # 216).

In the state “3”, the state is returned to the initial value “0” after the return of the scanner 30 is completed.

FIG. 7 is a flowchart of the belt mark detection processing of FIG.

Also in this routine, the mark state is checked first in step # 300, and the following processing is executed according to each state.

In state "0", the copy mode is checked after the print key 200 is turned on, and if the mode is the full color mode, the process proceeds to the next state (steps # 301 to # 303).

In the state "1", first, it waits for a mark detection permission flag to be set in the image forming process (step # 311).

When the mark detection permission flag is set, next, by referring to a scan table TS described later relating to the paper size or the document size and the copy magnification, it is determined whether or not scanning is possible each time the belt mark signal S10 is generated. Check (step # 312).

If scanning is possible each time the belt mark signal S10 is generated, the process proceeds to step # 314, and the state is updated to "2".

If it is not possible to scan every time the belt mark signal S10 is generated, a skip flag is set to invalidate the belt mark signal S10 with respect to scanning each time it is generated (step # 313). Update state.

 FIG. 14 shows the contents of the scan table TS.

The scan table TS stores the size of the paper P detected by the paper size sensors 81 and 82 in the case of automatic paper feeding or the size of the document D detected by the document size detecting device 101 in the case of manual paper feeding, and the numeric keypad 202. , The forward movement time of the scanner 30 determined in advance by the mutual relationship with the copy magnification set by using the above, and the number of generations of the belt mark signal S10 (“1” or “2”) which is a necessary condition for starting the scan Is stored as data.

In the notation of the paper size or the document size in the figure, for example, A3 portrait refers to the case where the A3 size paper P is fed with the longitudinal direction as the transport direction, or the A3 size document D is scanned in the longitudinal direction. Platen glass 28 as
A4 landscape means that A4 size paper P is fed so that its longitudinal direction is orthogonal to the transport direction, or A4 size original D is scanned in the longitudinal direction. This means that the original is placed on the platen glass 28 at right angles to the original.

In the copying machine 1, the peripheral length of the transfer belt 11 is 450 mm, and the system speed in a normal copying mode is 110 mm / sec.

Therefore, one rotation time of the transfer belt 11 (generation cycle of the belt mark signal) is 4.09 seconds.

On the other hand, in the scanner 30, the time required for the reciprocating movement including the acceleration, constant speed, and deceleration periods varies depending on the size of the sheet P or the document D and the copy magnification.

For example, when the same size copy is performed on the original D of A4 width, the time is 3.0 seconds (2.2 seconds for reciprocation and 0.8 seconds for backward movement). In this case, the movement time is the generation of the belt mark signal S10. Since the period is shorter than the period, scanning can be started continuously each time the belt mark signal S10 is generated (each rotation of the transfer belt).

On the other hand, even in the case of the same-size copying, in the case of the original D of A3 length, the reciprocating movement time of the scanner 30 is 5.4.
Second (4.2 seconds for forward movement and 1.2 seconds for backward movement), which is longer than the generation cycle of the belt mark signal S10.
Scanning cannot be started continuously for every 10 occurrences. Therefore, in this case, as described above, the belt mark signal S10 is invalidated every other generation, and scanning is started every two generations of the belt mark signal S10.

Returning to FIG. 7, in state "2", the belt mark signal S10 is checked (step # 321).

If the belt mark signal S10 is turned on (generated), an exposure lamp on timer consisting of a counter for determining the lighting timing of the exposure lamp 33 is set (step # 32).
2) The state is updated to "3" (step # 323).

That is, the transfer belt 11 is driven to rotate at a constant speed (system speed), and the generation cycle of the belt mark signal S10 is constant. Therefore, in the copying machine 1, in the scan started based on the belt mark signal S10, the time from the generation timing of the belt mark signal S10 immediately before the start of the scan is set so that the light amount of the exposure lamp 33 is stable. In order to turn on the exposure lamp 33 at an appropriate time, an exposure lamp on timer is provided.

As a result, useless lighting of the exposure lamp 33 and scanning in an unstable light amount state can be prevented.

In state "3", the control waits for the end of the timing of the exposure lamp on timer (step # 331, step # 33).
2).

At this time, the mark detection permission flag is checked again during the counting of the exposure lamp on timer (step # 337),
When the mark detection permission flag is reset in the image forming process, the state is returned to "0" in order to put the copying machine 1 in a standby state.

When the counting of the exposure lamp on timer ends, the exposure lamp 33 and the charger 4 are turned on in preparation for scanning (step # 333), and the scan permission flag checked in the above-described scanning process is set (step # 334). ).

Then, a scan monitoring timer is set to check whether the scan start timing is correct (step #).
335) to update the state to “4”.

In state "4", the state is updated to "5" after the belt mark signal S10 is turned on (step # 341).

In state “5”, the scan monitoring timer is updated (step # 345) and the end check is performed (step # 346). When a predetermined time has elapsed after the belt mark signal S10 is turned on and the scan monitoring timer ends, the state is changed to “5”. "6" is assumed.

In the state “6”, first, it is checked whether or not the scan has been started in the scan processing.

When the scan is started, the start failure counter indicating the number of times the scan has not been started at the regular timing and the scan permission flag are reset (steps # 352 and # 353).

Then, the step flag is checked (step # 354).

When the step flag is in the reset state, the scanning is started every time the belt mark signal S10 is generated. Therefore, the exposure lamp on timer is immediately set (step # 356), and the state is returned to "3" to return to the next state. Prepare for the scan.

When the skip flag is set, the scan is started every time the belt mark signal S10 is generated twice. In this case, the state is updated to “7” (step # 355), and the state “7” is set. , Waits for the belt mark signal S10 to turn on, sets the exposure lamp on timer (step # 372), and returns the state to "3".

On the other hand, if the determination in step # 351 is NO, that is, if the scan is not started for some reason despite the arrival of the scan start timing, the exposure lamp 33 and the charger 4 are turned off once ( (Step # 358), the scan permission flag is reset (Step # 359). Then, the start failure counter is incremented (step # 360).

Next, the value of the start failure counter is checked (step # 361).

If the value of the start failure counter is equal to or smaller than the predetermined allowable value, the process proceeds to the above-described step # 354 so as to try to start scanning again.

On the other hand, if the value of the start failure counter exceeds a predetermined allowable value, it is determined that the cause of the scan not starting is not accidental and natural recovery cannot be expected, and to notify the operator of the occurrence of the trouble. , Operation panel OP
The trouble display LED 224d is turned on (step # 362).

FIG. 8 is a flowchart of the cleaning process of FIG.

First, the cleaner state is checked (step # 400), and the following processing is executed according to each state.

In the state “0”, the fur brush 190 is pressed and the cleaner bias H
V is turned on to start cleaning the transfer belt 11 (steps # 401 to # 403).

In the state "1", first, the copy mode is checked (step # 411).

If the copy mode is the monochrome mode, the process proceeds to state "7" (step # 415).

On the other hand, when the copy mode is the full-color mode, the temperature of the solenoid 195 of the belt cleaner 19 is detected to correct the pre-cleaning time of the transfer belt 11, and the fur brush 190 is retracted based on the detection result. The correction value of the timer value of the evacuation timer for determining the timing is determined, and the process proceeds to state “2” (step # 41)
2 to Step # 414).

In the state “2”, when the scan is started, a value obtained by adding the correction value determined in the above-described step # 413 to a standard value predetermined as the timer value is set in the evacuation timer, and the state “3” is set. (Steps # 421 to # 423).

In the state "3", when the time of the evacuation timer ends, the evacuation of the fur brush 190 and the turning off of the cleaner bias HV are performed, thereby completing the pre-cleaning (steps # 431 to # 435).

In state "4", when the timing roller 46 is turned on at the registration timing, an image leading edge arrival timer is set (steps # 441 to # 44).
3). The image leading end arrival timer measures the time during which the portion of the transfer belt 11 corresponding to the leading end of the toner image rotates from the secondary transfer position to the position where the belt cleaner 19 is disposed.

In the state "5", when the counting of the image leading end arrival timer is completed, the cleaner bias HV is turned on and the fur brush 190 is pressed against to start cleaning after the transfer belt 11 (steps # 451 to # 454). .

Then, in order to correct the post-cleaning time of the transfer belt 11, the temperature of the solenoid 195 of the belt cleaner 19 is detected, and a timer value corrected based on the detection result is set in the evacuation timer (Step # 455, Step # 455). 456).

In state “6”, at the end timing of the evacuation timer, the fur brush 190 is evacuated and the cleaner bias HV is turned off (steps # 461 to # 4).
64).

Thereafter, if there is no next copy request, the state is set to “0”.
To the standby state, and if there is a next copy request, the state returns to state "4" (steps # 465 to # 46).
7).

On the other hand, if the print key 200 is turned on during the counting of the evacuation timer, that is, during the post-cleaning, the process returns to the state “1” (steps # 468 and # 469).

In states "7" and "8", a process for post-cleaning in the monochrome mode is executed.

First, in state "7", at the time when scanning is completed, it is checked whether or not there is a next copy request, and if there is no next copy request, a post-processing timer is set (steps # 471 to # 473). The post-processing timer measures one rotation time of the transfer belt 11. If there is a next copy request, no processing is performed because the fur brush 190 can be kept pressed.

Next, in the state "8", the fur brush 190 is evacuated after the post-processing timer is completed, the cleaner bias HV is turned off, and the state is returned to the initial value "0" (steps # 481 to # 481). Step # 485).

On the other hand, if the print key 200 is turned on while the post-processing timer is counting, the process returns to the state “1” (step #)
486, step # 487).

State “9” to state “11” are executed when the image formation is interrupted.

In the state "9", the process waits until the image formation interruption flag is reset (step # 491). Until the image forming suspension flag is reset, the retraction state of the fur brush 190 in the image forming state “14” of the image forming process is continued. That is, the cleaning of the transfer belt 11 is prohibited, so that the toner image is held on the transfer belt 11.

When the image formation suspension flag is reset, the copy mode is checked. In the case of the full color mode, the state returns to the state “4”.
0 ”(steps # 492 to # 494).

In state "10", at the registration timing,
The pressure welding timer is set, and the process proceeds to state “11” (steps # 501 to # 503). The insulation displacement timer is
A part corresponding to the leading end of the toner image on the transfer belt 11 corresponds to an image leading end timer used in the full color mode.
Is a timer for measuring the time for rotationally moving to the disposition position.

In state "11", after the end of the time of the pressure contact timer, the fur brush 190 is pressed and the cleaner bias H
V is turned on (step # 511 to step # 514).

Thereafter, if there is a next copy request, the state "7"
If there is no next copy request, a post-processing timer is set and the process returns to state "8" (steps # 515 to # 515).
Step # 518).

 FIG. 9 is a flowchart of the sheet feeding process of FIG.

First, the paper feeding state is checked (step # 60).
0), execute the following processing in each state.

In the state "0", the paper empty LED 249 is checked after the paper supply permission flag is set (step # 601, step # 602).

If the paper empty LED 249 is off, the pickup roller 44 or 45 is required to feed paper from the selected paper cassette 42 or 43 as a process for normal paper feeding. Paper feed roller 4
Turn on 7,48. That is, the conveyance of the sheet P is started by transmitting the driving force of the main motor 24 to each roller via the clutch (step # 603). Then, a paper feed jam timer for detecting the occurrence of a paper jam before the leading end of the paper P reaches the timing roller 46 is set, and the process proceeds to state "1" (steps # 604 and # 605).

On the other hand, when the paper empty LED 249 is lit, it means that the paper P in one of the selected paper cassettes 42 or 43 is insufficient. Is checked (step # 602, step # 606).

If the paper P in the other paper cassette 43 or 42 is also deficient, the secondary transfer is impossible, so that the image formation interruption flag is set and the main motor 24 is turned off to stop the conveyance of the paper P. Then, the paper supply permission flag is reset (step # 606, steps # 610 to # 612).
If there is paper P in the other paper cassette 43 or 42, it is checked whether or not the size of the paper P is a size capable of transferring the entire toner image already formed (step # 607).

If transfer is possible, after setting the stop flag,
The selection of the paper cassette is switched, and the paper is fed by the other selected paper cassette 43 or 42 (steps # 607 to # 609 and # 603).

If the transfer is not possible, an image formation interruption flag is set (step # 607, step # 610).

In state "1", the timing sensor 86 is turned on when the leading edge of the moving paper P reaches the timing roller 46, the rotating pickup roller 44 or 45 is turned off, and the paper feed jam timer is set. Reset is performed (steps # 621 to # 623). In addition, the rotation of the paper feed rollers 47 and 48 that were previously turned on is continued. As a result, the sheet P curves at the entrance of the timing roller 46, and a paper loop for correcting the inclination of the sheet P with respect to the transport direction is formed.

Then, a paper loop timer for measuring a time for obtaining an appropriate paper loop is set, and the process proceeds to state "2" (step # 624, step # 625).

In the state “2”, after the time of the paper loop timer ends, the rotation of the paper feed rollers 47 and 48 is stopped (steps # 631 to # 633).

In the state “3”, the control unit waits for the arrival of a registration timing that defines the alignment between the toner image on the transfer belt 11 and the paper P, and turns on the timing roller 46 at the registration timing to convey the paper P to the transfer position. Then, a discharge jam timer for detecting occurrence of a jam from the start of conveyance to the discharge of the paper P is set, and the transfer charger 17 for the secondary transfer is turned on (steps # 641 to # 644). .

In state "4", after the trailing end of the sheet P leaves the timing roller 46 and the timing sensor 86 is turned off, a charger off timer for determining the off timing of the transfer charger 17 is set (step # 65).
1, Step # 652).

In the state "5", the timing roller 46 and the transfer charger 17 are turned off after the timing of the charger off timer ends (steps # 661 to # 66).
Four).

In the state “6”, the completion of the discharge of the sheet P is confirmed by the detection state of the discharge sensor 88, the discharge jam timer is reset, and the state is returned to the initial value “0” (steps # 671 to # 673). .

FIG. 10 is a flowchart of the jam detection processing of FIG.

First, check the jam state (step #
700), execute the following processing in each state.

In the state "0", it is checked whether or not a jam has occurred by checking the normal state of the paper feed jam timer and the discharge jam timer (steps # 701 to # 7).
06).

Normally, the paper feed jam timer and the discharge jam timer are reset before the end of the timing.

However, if the counting of one of these timers is completed, the paper P has not reached the predetermined position after the scheduled time, and a jam has occurred during the conveyance. .

When a jam occurs, the operator is notified of the occurrence of the jam by turning on the jam display LED 224d, and then a check is performed to determine whether or not the secondary transfer is being performed (steps # 707 and # 708).

During the secondary transfer, that is, when a part of the toner image has already been transferred to the jammed sheet P, a complete copy image cannot be obtained even if a new sheet P is fed. . Therefore, in this case, as processing for stopping the image formation, the main motor 24 and the PC motor 25 are turned off, initial settings of various data for controlling the image formation, and a jam indicating that a jam is occurring. The occurrence flag is set, and the process proceeds to state “2” (steps # 713 to # 716).

On the other hand, when the secondary transfer is not being performed, after the jam occurrence flag is set, as a process for holding the toner on the transfer belt 11, an image formation interruption flag is set, the main motor 24 is turned off, and the state “ Go to "1".

When the main motor 24 is turned off, the conveyance system of the sheet P is stopped. However, since the image formation interruption flag is set, the PC motor is turned on until the time when the primary transfer is completed in the image formation processing.

In the state "1", the paper check process (step # 93) executed in the image forming restart process described later.
Wait for the jam occurrence flag to be reset by 1), then reset the jam occurrence flag and display the jam LE
D224d is turned off and the state is returned to "0" (step # 7)
21 to step # 723).

Also in the state “2”, the process waits for the jam occurrence flag to be reset by the paper check process executed as a subroutine, turns off the jam display LED 224d together with the reset of the jam occurrence flag, and returns the state to “0” (step # 731 to Step # 734).

FIG. 11 is a flowchart of the paper check process in step # 731.

The detection states of the paper detection sensor 85, the timing sensor 86, and the discharge sensor 88 are sequentially checked, and only when the outputs of all these sensors are off, the jammed sheet P is removed and the sheet It is determined that there is no P, and the jam occurrence flag is reset (steps # 741 to # 744).

FIG. 12 is a flowchart of the paper shortage detection processing of FIG.

First, it is checked whether the paper cassette selected as the paper feed port is the upper paper cassette 42 or the lower paper cassette 43 (step # 801).

The paper empty sensors 83 and 84 control the paper P of the selected one of the paper cassettes 42 and 43.
Is checked, and if there is paper P, the paper empty LED 249 is turned off, and if there is no paper P, the paper empty LED 249 is turned on (steps # 802 to # 80).
7).

FIG. 13 is a flowchart of the image forming restart processing of FIG.

First, the restart state is checked (step # 90).
0), the following processing is executed according to each state.

In the state "0", the image forming interrupt flag is checked to confirm whether or not there is a request to restart image forming (step # 901).

If the image formation interruption flag is set and the image formation restart is requested, the jam occurrence flag is checked, and the image formation interruption is performed depending on whether the interruption of the image formation is due to the lack of the paper P or the occurrence of the jam. Subsequent processing is divided (step # 902 to step # 904).

First, when the interruption of the image formation is due to the lack of the paper P, the state “1” and the state “2” are executed.

In state "1", paper empty LED2
After confirming that 49 has been turned off, the printer waits for the print key 200 to be turned on, and checks whether the copy mode has been changed after the interruption of image formation (steps # 911 to # 91).
3).

If the copy mode at the time of interruption of image formation and the current copy mode match, the main motor 24 and the PC motor 25
Is turned on, a motor rise timer is set, and the process proceeds to state "2" (steps # 914 to # 916).

On the other hand, if the copy mode is changed after the interruption of the image formation, the state of the image formation processing is returned to “0”, the image formation interruption flag is reset, and the state returns to the state “0” (step #).
917 to step # 919). As a result, the operation state of the copying machine 1 becomes a standby state.

In state "2", the paper feed permission flag is set after the completion of the counting of the motor start timer, the image formation interruption flag is reset, and the state returns to "0" (steps # 921 to # 925).

By resetting the flag of the image forming suspension, in the state “15” of the image forming process, the image forming state is returned to the image forming state next to the image forming state executed at the time of the image forming suspension.

In the state “3”, a process for resuming the image formation interrupted by the occurrence of the jam is executed.

That is, after confirming that the jam occurrence flag has been reset by the paper check process of FIG. 11, the printer waits for the print key 200 to be turned on, and checks whether the copy mode has been changed after the image formation was interrupted. (Step # 931 to Step # 934).

If the copy mode is not changed, the main motor 24 and
The PC motor 25 is turned on, the motor start timer is set, and the process proceeds to state "2" (steps # 935 to # 937).

On the other hand, if the copy mode has been changed after the interruption of the image formation, the state of the image formation processing is returned to "0", the image formation interruption flag and the paper feed permission flag are reset, and the state returns to the state "0" (step # 938 to step # 941).

Although illustration of the flowchart is omitted, when the composite monocolor mode for forming a composite monocolor copy image is selected, as described above, the belt mark signal S1 is output.
By the scan based on 0, multiple transfer of two color toner images is performed.

In the above-described embodiment, among the processes executed by the CPU 401, step # 610 of the sheet feeding process corresponds to the image forming interrupting unit which is a component of the first aspect of the present invention, and step # 710 of the jam detection process is , Corresponds to the image forming interruption means of the invention of claim 2. Further, the state “15” of the image forming process is defined in claim 1.
And the image forming continuation means of the invention of claim 2. Further, Step # 713 and Step # 714 of the jam detection processing
Corresponds to the image forming stop means of the invention of claim 3.

According to the above-described embodiment, if the paper P runs short or a jam occurs after the image formation is started, the image formation is interrupted after the primary transfer of the already formed toner image is completed. Then, since the image formation is continued after the supply of the paper P or the elimination of the jam, the waste of toner can be eliminated. That is, the toner can be effectively used.

According to the above-described embodiment, when a jam occurs during the secondary transfer, the image formation is immediately stopped, and each unit of the copying machine 1 is returned to the standby state. Retention is prevented and new imaging can be started quickly.

In the above-described embodiment, the contents and order of the flowchart, the structure of each member of the copying machine 1 including the means for storing the paper P,
The shape, material, position, number, and the like can be variously changed in addition to the above.

〔The invention's effect〕

According to the first aspect of the present invention, it is possible to prevent wasteful consumption of toner when the recording paper runs short during image formation.

According to the second and third aspects of the present invention, it is possible to prevent wasteful consumption of toner when a paper jam occurs during image formation.

[Brief description of the drawings]

1 is a cross-sectional front view showing a schematic configuration of a copying machine, FIG. 2 is a plan view of an operation panel provided on an upper surface of the copying machine, FIG. 3 is a block diagram of a control unit of the copying machine, and FIG. 13 to 14 are flowcharts showing the operation of the copying machine, FIG. 14 is a diagram showing the contents of the scan table, and FIG. 15 is a sectional front view of the belt cleaner. 1 ... copier, 3 ... photoconductor drum (photoconductor), 11 ...
Transfer belt (intermediate transfer medium), 83, 84 …… Paper empty sensor (paper empty detection means), 85…
… Paper detection sensor (jam detection means), 86 …… Timing sensor (jam detection means), 88 …… discharge sensor (jam detection means), 401 …… CPU (image formation interruption means,
Image forming continuation means, image forming stop means), D: original, P: paper (recording paper).

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yutaka Karaki 2-3-3 Azuchicho, Chuo-ku, Osaka-shi, Osaka Osaka International Building Minolta Camera Co., Ltd. (56) References JP-A 1-269956 (JP) JP-A-62-17768 (JP, A) JP-A-63-210958 (JP, A) JP-A-58-214172 (JP, A) JP-A-58-179874 (JP, A) 3-196066 (JP, A) JP-A-58-93072 (JP, A) JP-A-61-29357 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/00 303 G03G 15/36 G03G 21/00 370-540 G03G 21/02-21/04 G03G 21/14 G03G 21/20

Claims (3)

(57) [Claims] 1. An image forming apparatus for forming an image on recording paper by an image forming process based on electrophotography, comprising: a photosensitive member having a toner image formed on a surface thereof; and a toner image primarily transferred from the photosensitive member. 2 on the recording paper
An intermediate transfer medium for the next transfer, a paper empty detecting means for detecting the presence or absence of a recording paper, and a paper empty detecting means after the start of the image forming process and before the completion of the primary transfer. An image forming interrupting means for completing the primary transfer and holding the toner image on the intermediate transfer medium to interrupt the image forming process when a shortage is detected; An image forming apparatus, comprising: image forming continuation means for continuing the image forming process interrupted by the image interrupting means. 2. An image forming apparatus for forming an image on recording paper by an image forming process based on electrophotography, comprising: a photosensitive member having a toner image formed on a surface thereof; and a toner image primarily transferred from the photosensitive member. 2 on the recording paper
An intermediate transfer medium for the next transfer; a jam detection unit for detecting a jam of the recording paper; and a jam of the recording paper by the jam detection unit after the start of the image forming process and before the completion of the primary transfer. An image forming interrupting means for completing the primary transfer when the detection is detected and holding the toner image on the intermediate transfer medium to interrupt the image forming process; An image forming apparatus, comprising: image forming continuation means for continuing the image forming process interrupted by the image interrupting means. 3. The holding of the toner image on the intermediate transfer medium by the image forming interrupting means when the jam detecting means detects the jam of the recording paper during the transfer of the toner image from the intermediate transfer medium. 3. The image forming apparatus according to claim 2, further comprising image forming stopping means for stopping an image forming process.