JPH03218880A - Image forming device - Google Patents

Abstract

PURPOSE:To shorten warm-up time, upon occurrence of abnormal take-up, by continuing the operation of a fixing means upon detection of abnormal take-up of an image forming medium whereas stopping the operation of the fixing means upon detection of abnormal carriage of the image forming medium. CONSTITUTION:Upon initialization of data of such as a RAM through a CPU 350, an input register 358 reads in the states of switches and checks whether an operator call state such as paper jam has been occurring, and if it has not occurred heating of a fixing unit 37 is started. In other words, a heater lamp 37a and an exposure unit 21 are turned ON followed by sequential turn ON of a charger S22 and a develop bias S20 with predetermined time intervals. Upon elapse of a predetermined time under this state, they are turned OFF to complete warm-up operation of an image forming device. Upon elapse of a predetermined time after paper P feed from a paper cassette 22 toward aligning pair rollers 25 along a paper carry path 24, turn ON of an aligning switch 48 is checked and if it is not turned ON, it is recognized as paper jam.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Field of Industrial Application) The present invention relates to an image forming apparatus such as a laser printer.

(Prior Art) Conventionally, image formation in an image forming apparatus such as a laser printer is performed through various steps such as charging, exposure, development, transfer, peeling, cleaning, and fixing. In such an image forming apparatus, a charging device, an exposure device, a developing device, a transfer device, a peeling device, a cleaning device, etc. are sequentially arranged around the photoreceptor, and a fixing device is further provided to receive paper from the peeling device. The above image forming processes are executed by driving each of the above devices according to the rotational movement of the paper feed cassette (accommodating means) to form an image on the paper (image forming medium) fed and conveyed. The paper will then be ejected onto the ejection tray.

In such a laser printer, when a paper jam occurs at the start of paper feeding or during paper transport, the state is maintained and the power supply to the heater lamp in the fixing device is cut off. Then, after the paper jam is removed (released) and the operation is restarted, power is supplied to the heater lamp and the heater lamp is turned on.

For this reason, any paper jam would cut off the power supply to the heater lamp, so after the paper jam was removed,
It always takes time to reach the temperature required for fixing.

Therefore, even if there is a paper jam in which the paper has not reached the fixing device, the power supply to the heater lamp is cut off, so the warm-up time at the time of the paper jam is long. be.

(Problems to be Solved by the Invention) As described above, this invention has the disadvantage that it takes a long time to warm up when an abnormality occurs in taking out the image forming medium from the storage means in which it is stored. It is an object of the present invention to provide an image forming apparatus that can shorten the warm-up time when an abnormality occurs in taking out an imaged 11β forming medium from a storing means in which it is stored. purpose.

[Structure of the Invention (Means for Solving the Problems) The image forming apparatus of the present invention includes a storage means in which an image formation medium is stored, and a storage means for taking out and transporting the image formation medium stored in the storage means. an image forming means for forming an image on the image forming medium conveyed by the conveying means; a fixing means for fixing the image forming medium on which the image has been formed by the image forming means; a first detection means for detecting an abnormality in taking out the medium when taking out the medium; a second detection means for detecting an abnormality in the conveyance of the image forming medium by the conveying means; and a first detecting means for detecting an abnormality in the conveyance of the image forming medium by the first detecting means. control means for continuing the operation of the fixing means when an abnormality is detected, and for stopping the operation of the fixing means when the second detection means detects an abnormality in conveyance of the image forming medium; It consists of

(Function) The present invention causes the fixing means to continue operating when an abnormality in taking out the image forming medium is detected, and causes the fixing means to continue operating when an abnormality in the conveyance of the image forming medium is detected. It is designed to stop the operation.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 show the configuration of an image forming apparatus according to the present invention, for example, an image forming unit apparatus including a laser printer with optional equipment.

That is, the image forming unit device includes a multi-cassette feeder 2 that feeds paper (plain paper) P of a predetermined thickness such as cut paper as an image forming medium into a printer 1, and a multi-cassette feeder 2 that feeds paper (plain paper) P of a predetermined thickness such as cut paper as an image forming medium into the printer 1; The laser printer includes optional equipment such as an envelope feeder 3 that feeds paper (cardboard) A that is thicker than paper into the printer 1, and a jogger 4 that serves as a sorting device that sorts paper P or paper A after image formation into predetermined numbers. 1 and configured. The multi-cassette feeder 2, envelope feeder 3, and jogger 4 are connected online to a control section (not shown) in the main body of the laser printer 1. An operation panel 100 is provided on the upper surface of the laser printer 1.

Further, inside the laser printer 1, a laser optical system 12, a photosensitive drum 17, a charging device 18, a developing device 19, a transfer device 20, a static eliminator 2l, a peeling device 35, a fixing device 37,
In addition to process systems such as the cleaning device 45, there is also a paper feed cassette 22, a feed port roller 23, and an aligning roller pair 25.
, conveyor belt 3B, gate 38, paper ejection roller pair 39, 4
2 etc. are provided. The laser optical system l2 includes a semiconductor laser oscillator (not shown) that generates laser light;
A collimator lens (not shown) corrects the laser beam from this oscillator into parallel light, and a polygon mirror (as a rotating body) having a part of an octahedral mirror that reflects the laser beam from this lens for each scanning line. rotating mirror) 13
, f/θ lens l4, mirrors 15 and 1B, and a mirror motor 60 that rotates (drives) the polygon mirror 13.
It is composed of etc.

During the image forming operation, the laser beam from the laser optical system 12 corresponding to an image signal from an external device (not shown) or the operation panel 100 is emitted from the photoreceptor tram 17.
imaged on the surface of The photosensitive tram 17 rotates in the direction of the arrow shown in the figure, and the surface thereof is first charged by a charging device 18, and then exposed in accordance with an image signal by a laser optical system 12. That is, the laser beam generated from the semiconductor laser oscillator moves at a constant speed from the left to the right of the photoreceptor 17 (from the front side to the back side in FIG. 6) as the polygon mirror 13 is rotated by the mirror motor 60. An electrostatic latent image is formed on the surface. This electrostatic latent image is made visible by applying toner to it by the developing device 19.

On the other hand, the paper P serving as the image forming medium in the paper feed cassette 22 is taken out one by one through the delivery port 23, and the paper P is taken out from the paper guide path 23.
4, and is guided to a pair of aligning rollers 25, and sent to a transfer section by this pair of rollers 25.

Also, the paper P that is taken out one by one from the paper feed cassette 30 in the multi-cassette/sotofeeder 2 at the delivery port 32 and guided to the aligning roller pair 25 through the paper guide paths 34 and 29 is delivered to the transfer section. Alternatively, sheets P1 are taken out one by one from the paper feed cassette 31 at the delivery port 33 and guided to the pair of aligning rollers 25 through the paper guide paths 34 and 29, or from the stacker 2B in the envelope feeder 3 at the delivery port. The sheets A1 are taken out one by one by the roller 27 and guided to the pair of aligning rollers 25 through the sheet guide paths 28 and 29, and then fed from the manual paper feed section 44 and passed through the sheet guide path 29 to the aligning roller pair. The paper P guided to the pair 25 is sent in accordance with a designation from the external device or the operator.

Then, the paper P or paper A sent to the transfer section is brought into close contact with the surface of the photoreceptor drum l7 at the transfer device 20, and the toner image on the photoreceptor drum l7 is transferred by the action of the transfer device 20. . The transferred paper P or paper A is peeled off from the photoreceptor drum l7 by the action of a peeling device 35, and is sent to a fixing device 37 by a conveyor belt 36, where it passes through a heat roller that generates heat for fixing. 37. The transferred image is then heat-fixed. This heat roller 371 has a built-in heater lamp 37a for heating. After fixing, the paper P or paper A passes through a gate 38 and is delivered to the paper ejection tray 4 by a pair of paper ejection rollers 39.
0 or the upper conveying path 4 by the gate 38
1, and is sent to the jogger 4 by a pair of discharge rollers 42.
The paper is discharged onto a paper discharge tray 43 which is movably supported by the paper.

Further, the photosensitive drum 17 after the transfer is cleaned by a cleaning device 4.
After the residual toner is removed in step 5, the residual image is erased by the static eliminator 21, thereby making it possible to perform the next image forming operation.

Note that the fixing device 37 is formed into a unit (fusal unit), and is configured to be able to be attached to and detached from the printer 1 independently. Further, the aligning roller pair 2
5, there is an aligning switch 48 for detecting a paper feeding error to the transfer section by the aligning roller pair 25, etc.; , 42 is provided.

In addition, the paper feed cassettes 22, 30, 3l have paper P
Paper detectors 50, 5l, and 52 are arranged to detect the presence or absence of paper P in the paper feed cassettes 22, 30, and 31, respectively.

Further, a paper detector 53 is disposed within the envelope feeder 3 for optically detecting the removal of the paper A from the stacker 26.

Further, above the laser optical system l2, there is an engine control board equipped with an engine control circuit 70 that controls each electrical device provided in the apparatus main body 1 to control operations for completing the electrophotographic process. A board mounted with a printer control circuit 7l that controls the operation of the engine control circuit 70 is arranged.

Up to three boards for the printer control circuit 71 can be installed in accordance with the need for additional functions (for example, adding more types of fonts, kanji, etc.). Further functions can be added by inserting function-adding IC cards 517 into three IC card connectors 72 arranged on the front edge of the control circuit 7l board. Furthermore, a connector (not shown) for connecting to a post device 409 (described later), which is an external output device such as a computer or word processor, is provided on the left end surface of the board of the printer control circuit 7I located at the bottom. There is.

As shown in FIG. 3, the operation panel 100 has a number of panels,
Liquid crystal display 100 that displays modes, guidance messages, etc.
a. LED display 10 that lights up and displays various statuses with LEDs
0b, a switch 100c for instructing various operations, and an online key 100 for switching between online and offline.
6. The LED display 100b indicates whether it is connected to an external device, that is, "online" indicating online/offline mode, "ready" indicating that the device main body 1 is ready for operation, and indicating that image transfer is in progress. "Data" to indicate, "Operator" to request an operator call, "Request a service call"
It consists of indicators for ``service'' and ``mode'' indicating auto/manual.

The switch 100c includes, for example, a menu key, a value key, a numeric keypad (not shown), or the like. The above menu keys are for “Next item” and “
It consists of two keys for "previous item", and the LCD display 10
The multiple menu information displayed on the left half of 0a is incremented each time the "Next item" key is pressed, and the "Previous item"
Each time you press a key, it is decremented and displayed,
These display operations are cyclically repeated. The value key is also composed of two keys, "Next item" and "Previous item", and the "Next item" key can be used to select multiple value information corresponding to the menu information displayed on the left half of the liquid crystal display 100a. Each time the key is pressed, it is incremented, and each time the "previous item" key is pressed, it is decremented and displayed on the right half of the liquid crystal display 100a, and these display operations are repeated cyclically. , the desired operation is selected and instructed by operating the menu keys and value keys.

Next, the configuration of the engine control section will be explained.

FIG. 4 is a block diagram showing the configuration of main parts of the engine control section 300. In the figure, 302 is a power supply device;
By turning on the main switch 301, +5V and +24V power supply voltages are output. The power supply voltage of +5V is supplied to the engine control circuit 70, and further supplied to the printer control circuit 71 via the engine control circuit 70.

On the other hand, the +24v power supply voltage is the cover switch 303, 3
04 and is sequentially supplied to the engine control circuit 70.

The power is then supplied to the scanner control circuit 10l, the high-voltage power supply 305, and the mechanism drive circuit 306 through the engine control circuit 70, respectively. The scanner control circuit 101 is connected to the semiconductor laser 90 and the mirror motor 92, and the mechanism drive circuit 30B is connected to the pre-exposure device 2L.
The main motor 3o7, manual paper feed solenoid 308, cassette paper feed solenoid 309, aligning solenoid 310, toner replenishment solenoid 311, cooling fan 500, etc. are each supplied with power, and are used as driving power sources for these.

Further, the power supply device 302 is provided with a zero-cross switch type heater lamp drive circuit (not shown) consisting of, for example, a phototriac coupler and a triac, which drives the heater lamp 501 inside the fixing device 33. The above +24v is used as a driving power source for the light emitting side LED. In the heater lamp drive circuit with this configuration, as is well known, the light emitting side L
When the ED is turned on/off, the phototriac on the light emitting side is turned on/off at the zero cross point of the AC power supply, thereby turning on/off the triac, which is the main switch element in the next stage, and energizing the AC power supply S1 to the heater lamp 37a. Or it will turn off. And the light emitting side LED
A heater control signal S2 for turning on/off is supplied from the engine control circuit 70 to the power supply device 302, and a temperature signal detected by the thermistor 37b provided in the fixing device 37 is supplied to the engine control circuit 70. It is now possible to do so.

Further, the cover switch 303 is turned off when the top cover (not shown) is rotated upward, and the cover switch 304 is turned off (not shown) when it is opened. Therefore, when the top force bar or the rear force bar is open, the switches 303, 3
Since +24V is cut off by 04, the operation of the semiconductor laser 90, mirror motor 60, high voltage power supply 305, main motor 307, solenoids 308 to 3l1, cooling fan 500, heater lamp 37a, etc. is stopped, and the operator Even if the inside of the device main body 1 is touched, there will be no problem.

FIG. 5 is a block diagram showing the configuration of the engine control circuit 70. In the figure, the CPU 350 is the engine control unit 3
It controls the entire 00, and operates according to a control program stored in the ROM 351. RAM 352 is used as a working buffer for CPU 350. E2PRO
M353 stores the total number of prints, etc. The printer interface circuit 354 receives an interface signal S with the printer control circuit 7l.
It is designed to mediate the delivery of 3 items. The laser modulation control circuit 355 controls the semiconductor laser 90 to be forced to turn on periodically in order to generate a laser light detection signal S4, which will be described later, and also controls the interface signal S.
3 modulates the semiconductor laser 90 according to the image data sent from the printer control circuit 71, and transmits the laser modulation signal S5 to the scanner control circuit 101.
It is designed to output to .

The output register 356 receives control signals S6 and S that respectively control the mechanism drive circuit 306, the high voltage power supply 305, the scanner control circuit 101, and the heater lamp drive circuit.
7, S8, and S2 are output. The voltage signals S9 and SIO generated by the thermistor 37b and the toner sensor 324 are input to the A/D converter 357, and these voltage values are converted into digital values. The input sensor 358 includes the vapor empty switch 320, manual feed switch 32l1, paper ejection switch 49, 49, mounting switch 323, aligning switch 48, and paper detectors 50, 51, 52,
Status signals S11, S12, S13, Sl4 from 53,
S15, S17, and the +24V on/off status signal S1B are input. In addition, the internal bus 359 is
The above CPU 350, ROM351, RAM35
2, E2PROM 353, printer interface circuit 354, laser modulation control circuit 355, output register 35B, A/D converter 357, input register 35
8 and exchange data with each other.

The mechanism drive circuit 30B is provided with a drive circuit for driving various motors, solenoids, etc.
On/off is controlled by a binary control signal S6 output from the output register 356. That is, for example, each drive circuit is turned on when it is "1" and turned off when it is "0", and the pre-exposure device 21, main motor 307, solenoids 308 to 311, and cooling fan 500 are
V is energized or cut off. The scanner control circuit 101 is provided with a drive circuit for a semiconductor laser 90 and a mirror motor 60. The semiconductor laser 90 is turned on/off by a laser modulation signal S5 outputted from the laser modulation control circuit 355, and the mirror motor 60 is turned on/off by a control signal S8 outputted from the output register 356. It has become so. Further, a PIN diode is used in the laser light detection sensor 312, and when the laser light a passes through the laser light detection sensor 312, a current proportional to the energy flows therethrough.

This current signal is sent to the laser modulation control circuit 355 as a laser light detection signal S4. Further, from the high voltage power supply 305, a developing bias power supply section (not shown), a charging device l8, and a wire high voltage power supply section (not shown) of the transfer device 20 are connected to a developing bias power supply section (not shown), a developing bias power supply section (not shown), and a developing bias power supply section (not shown), respectively.
High voltage signals for charging S22 and transfer S24 are output.

These ON and OFF states are controlled by 1 and 0 of the control signal S7 output from the output register 35B.

As described above, within the engine control section 300, power is supplied to each electric circuit via the engine control circuit 70, and each section is controlled by binary control signals output from the engine control circuit 70. It looks like this. This engine control section 300 and a printer control section 400, which will be described later, are connected by an interface signal S3.

Next, the configuration of printer control section 400 will be explained.

FIG. 6 is a block diagram showing the configuration of the main parts of the printer control section 400. In the figure, a CPU 401 controls the printer control unit 400 as a whole.

The ROM 402 stores a control program, and the CPU 401 operates according to this program. The ROM 402 also stores data regarding the paper P such as a password to be verified when changing data, a top margin, a left margin, a vapor type, message information to notify the operator, and the like. The RAM 403 is used as a page buffer for temporarily storing image data sent from the host device 409. Expanded memory 4
04 is a large-capacity memory used when the image data sent from the host device 409 is a large amount of data such as bitmap data and the RAM 403 cannot store one page of data. Video RAM4
05 stores image data developed into a bit image, and this output is sent to the serial-parallel conversion circuit 4.
06. The serial-to-parallel conversion circuit 406 converts the image data developed into a bit image in the video RAM 405 and sent as parallel data into serial data, and sends the serial data to the engine control circuit 70.

The host interface 408 exchanges data between the printer control unit 400 and a host device 409, which is composed of, for example, a computer or an image reading device, and has two types: a serial transfer line 410a and a parallel transfer line 410b. We are prepared. Then, it can be used appropriately depending on the type of data transferred to and from the host device 409. The engine interface 411 mediates the exchange of an interface signal S3 between the printer control circuit 7l and the engine control circuit 70. The connection circuit 413 connects the IC card 517 when the IC card 517 is inserted into the connector 16 or removed from the connector l6.
This is to prevent the data stored in the IC card 517 from being destroyed due to noise generated during insertion/removal by cutting off the power supply and signal line supplied to the IC card 517.

The operation panel control circuit 407 controls displaying a guidance message on the liquid crystal display 100a of the operation panel 100;
The CPU 4 controls the lighting, turning off, and blinking of the LED display 100b, or the data input manually from the switch l00c.
This is used to control the transmission to 01. Further, the internal bus 412 is connected to the CPU 401 and the ROM 402.
, RAM403, expansion memory 404, video RAM4
05, the operation panel control circuit 4o7, the host interface 408, the engine interface 411, and the connection circuit 413.

Further, the IC card 517 is a non-volatile memory, for example, a static RAMSE2P with battery backup.
It is composed of ROM, EPROM, mask ROM, etc. These IC cards 517 store, for example, character fonts, emulation programs, and the like.

Next, the configuration of the interface signal S3 will be explained.

FIG. 7 shows each signal of the interface signal S3. In the figure, DO-D7 is an engine control circuit 70
This is a bidirectional data bus that transmits status from the printer control circuit 71 to the printer control circuit 71 and commands from the printer control circuit 71 to the engine control circuit 70, and the status and commands are switched and used at the timing shown in FIG. It looks like this. That is, the engine control circuit 7o
When the bus direction signal DIR is set to a low level when the busy signal BSYO output from the DO-D7 is at a high level (not busy), the DO-D7 is switched in the direction of transmitting a signal from the engine control circuit 70 to the printer control circuit 71. The status is output on DO-D7. This allows the printer control circuit 7l to read the status.

On the other hand, when the printer control circuit 71 sends a command, when the bus direction signal DIR is set to a high level when the busy signal BSYO is at a high level (not busy), the DO-D7 sends a signal from the printer control circuit 71 to the engine control circuit 70. The direction is switched to transmit the command, and the command is output on the DO-D7. When the strobe signal STBO is set to a low level in this state, the engine control circuit 70 reads the command on DO-D7 while the strobe signal STBO is at a low level, and the busy signal BSYO is set to a low level (busy state). . In this busy state, the engine control circuit 70 performs processing such as command analysis. When the busy signal BSYO is set to a low level, the printer control circuit 71 returns the strobe signal STBO to a high level and finishes sending the command. Then, when the command processing in the engine control circuit 70 is completed, the busy signal B
SYO is returned to high level again.

Note that commands sent while the busy signal BSYO is at a low level are not received by the engine control circuit 70. Furthermore, the status on the data path DO-D7 does not change immediately when there is a change in status in the engine control unit 300, but is updated only when the status is returned in response to a command received after the status change. There is.

The attention signal ATN1 is output when the basic status on the print sequence between the engine control circuit 70 and the printer control circuit 71 changes, and the attention signal ATN1 is output when the basic status on the print sequence between the engine control circuit 70 and the printer control circuit 71 changes.
It is set to a high level when it becomes possible to receive a SYNC command and when reception of one page of image data is completed.
It is reset to a low level when an attention reset command is received. Therefore, when the attention signal ATN1 changes from a low level to a high level, the printer control circuit 7l operates on the data path DO-D.
7, resets the attention signal ATN1, and then sends an attention reset command to the data path D.
It is now possible to read the status on the o-D7 and know the changed basic status. In addition, the above basic status is also output on the data path by the basic status request command that requests the basic status, so the content of the changed basic status can be known by the basic status request command prior to the above attention reset command. is now possible.

The letty signal PRDYO indicates that the engine control unit 300 is in a ready state when it is at a low level, and indicates that the engine control unit 300 is in a ready state when it is at a high level.When this signal is at a low level, a printing operation by the engine control unit 300 is possible. It is.

The system clear signal SCLRI is the printer control circuit 7l.
200~ after +5v rises with the reset signal of
The level remains high for 500 msec, during which the printer control circuit 71 enters the reset state.

The prime signal PRIMEO is a reset signal to the engine control circuit 70. While this signal is at a low level, the above-mentioned busy signal SYO is at a low level, the ready signal PRDYO is at a high level, and the engine control circuit 70 is at a predetermined initial state. Return to state.

The horizontal synchronization signal HSYNCO is a signal generated every time one line is scanned by the laser exposure unit 22.
The number of lines corresponding to the effective print length in the transport direction of the paper P after receiving the NC command is output in synchronization with the laser light detection signal S4.

The video clock VCLKO is the horizontal synchronization signal HSY
This is a synchronization clock for manually inputting one line of video data (image data) VDO to the engine control circuit 70 following the NCO, and is output in a number corresponding to the effective print width of the paper P in the horizontal scanning direction. Then, the video data VDO is taken into the engine control circuit 70 in synchronization with the falling edge of the video clock VCLKO.

According to the video data VDO, the laser exposure unit 22 performs exposure scanning on the photosensitive drum l7 to form a latent image on the photosensitive drum l7. In addition,
When the video data VDO is at a low level, it is visualized on the paper P as a dot image.

Next, in the above configuration, FIGS. 9(a) to (e)
) and the timing chart shown in FIG. 10, the operation of the engine control section 300 of the laser printer will be described.

First, when the main switch 301 is turned on, a reset signal (not shown) is generated in synchronization with the rise of the +5V power supply.
occurs, and the engine control circuit 70 enters a reset state. In addition, this reset signal causes the printer control circuit 7l reset signal SCLRI (see Figure 7)
is output, and the printer control circuit 71 is also reset. Then, after the +5V power supply is turned on, 200 to 50
After 0 msec, the value of the reset signal is inverted, the reset state is released, and the CPU 350 starts executing the program stored in the ROM 351.

That is, first, data such as RAM 352 is initialized (step ST50). Next, the status of each switch is read into the manual register 358 to prevent paper jams and
It is checked whether an operator call state such as a paper jam other than paper feeding, a cover open, a process unit not installed, or a paver empty has occurred (step ST51).

Here, if an operator call is occurring, it is checked whether only paper empty is occurring (step ST52), and if an operator call other than paper empty is occurring, step ST51 is performed.
Return to , and wait for the operator call state to be released.

On the other hand, when only vapor exhaust is occurring in step ST52, or when no operator call is occurring in step ST51, heating of the fixing device 37 is started (step ST53). That is, the heater lamp 37a is turned on. Next, the main motor 307 and the pre-exposure device 2l are activated to initialize the electrophotographic process.
is turned on (step ST54), and then charging S22 is sequentially performed at time intervals determined by the program.
is turned on (step ST55), and the developing bias S20 is turned on (step ST55).
is turned on (step ST56). In this state, it is checked whether a certain period of time (approximately 30 seconds) has elapsed (step ST57), and until the certain period of time has elapsed, it is checked whether or not the cover has opened (step ST90). . When the cover oven occurs, each output turned on in steps ST53 to ST56 is turned off (step ST91), and the process returns to step ST51. On the other hand, when it is confirmed in step ST57 that a certain period of time has elapsed, the charging S22 is turned off (step S758), and then the developing bias S20 is turned off in sequence at the timing determined by the program (step ST59), and the main Motor 307 and pre-exposure device 21 are turned off (step ST60). The warm-up operation of the image forming apparatus is completed through the series of operations from steps ST53 to S60.

Then, the ready signal PRDYO is output (changed from high level to low level), a print request is set to the data path Do-D7, and the attention signal ATN1 is outputted (changed from low level to high level).
and becomes ready for printing (step ST61). Note that the fixing device 37, which has started heating in step ST53, is at a temperature sufficient for a fixing operation in the process leading to step ST61.

At this time, the heater lamp 37a is turned on and off so that the fixing temperature in the fixing device 37 is within a predetermined temperature range based on the temperature detected by the thermistor 37b. Furthermore, when an operator call occurs, its contents are transmitted on the data path as the operator call status. Meanwhile, in the state of step ST61, the printer control circuit 7l sends the above-mentioned attention reset command to reset the attention signal ATN1 to a low level, and then recognizes the print request by reading the status on the data path according to the above procedure. be able to. In FIGS. 9(a) to 9(e), the attention reset command, the process of resetting the attention signal ATN1 (changing from high level to low level), and the operation of the second bundle are omitted.

Next, it is checked whether a print command has been received (step ST62). When a print command is not received, it is checked whether an operator call has occurred (step ST92), and when an operator call has occurred, the print request is canceled and the operator call status is set. The ready signal PRDYO is set to high level (step ST94). Then, it is checked whether or not a cover opening has occurred among the causes of the operator call (step ST95). If this cover open occurs and it is time to clear the paper jam (step ST
IOO), the cover is closed (step ST10).
1) When the paper jam is cleared (step ST102)
), the process returns to step ST61 in the ready state. In this case, the heater lamp 37a is still controlled on and off based on the temperature detected by the thermistor 37b, and the operation of the fixing device 37 is continued. Also, step S
If a cover oven occurs at T95 and it is time to clear a paper jam other than paper feeding (step STIOO),
The operation of the fixing device 37 is stopped by turning off the power supply to the heater lamp 37a (step ST103),
When the cover is closed (step ST104) and the paper jam is cleared (step ST105), the process returns to step ST51.

On the other hand, if cover oven is not occurring, step S
The process returns to T92 and waits for the operator call to be released. In step ST92, if no operator call has occurred, it is checked whether the ready signal PRDYO is at a low level (step ST93), and if this signal is at a low level, the process returns to step ST62 and waits for a print command. When the level is high, it has already entered the not-ready state in step ST94, so the process returns to step ST61 and the ready state is returned again. That is, the flow of steps ST62→ST92→ST93→ST62 is a state of waiting for a print command, a so-called standby state.

When it is determined in step ST62 that a print command has been received, a print request is set and a series of print operations are performed. And the lth
As shown in Figure O, first, the mirror motor 60 is turned on (step ST63), then the main motor 307 and the pre-exposure device 2l are turned on in sequence at predetermined time intervals (step ST64), and the charging S22 and the cassette are turned on. The paper feed solenoid 309 is turned on, and the basic status is set to paper conveying (step ST65).
). Further, the developing bias S20 is turned on (step ST66), and the cassette paper feed solenoid 309 is turned off (step ST67). Here, while the cassette paper feed solenoid 309 is on, the
3 rotates once, and the paper P is taken out from the paper feed cassette 22 and conveyed along the paper conveyance path 24 toward the aligning roller pair 25. Then, after a certain period of time has elapsed since the sheet P was fed, it is checked whether or not the aligning switch 48 is on (step ST68). When the aligning switch 48 is not turned on, the paper P is
It is determined that the paper has not reached this point and is treated as a paper jam. That is, the operator call status (jam) is set and the ready signal PRDYO is made high (step ST96). moreover,
Each device turned on in the process from step S763 to step ST66 is turned off in sequence at a timing determined by the program (step ST97), and the process returns to step ST92 to wait for the jam to be cleared. At this time, the heater lamp 37a is still controlled to be turned on or off based on the temperature detected by the thermistor 37b.

On the other hand, when the aligning switch 48 is on in step ST68, the VSYNC request is set and the attention signal ATN 1 is output (
(change from low level to high level) (step ST6
9). Then, it is checked whether or not the VSYNC command has been received (step ST70). When the VSYNC command is received, the VSYNC request is reset, and it is set whether data is being transferred, and laser exposure is started. That is, the reception of the video data VDO is started while transmitting the horizontal synchronization signal HSYNCO and the video clock VCLKO, and the video data VDO is written on the photoreceptor drum l7.
The image pattern by O is exposed (step ST7
1). Note that until step ST71, the pair of aligning rollers 25 remains stopped, so the paper P stops when its leading edge reaches the pair of aligning rollers 25. After a certain period of time has elapsed, the aligning solenoid 310 is turned on (step ST72), and as a result, the aligning roller pair 25 begins to rotate and the paper P is conveyed toward the transfer device 20. Note that the aligning solenoid 310 is operated in step ST. It is turned on at a timing such that the leading edge of the image on the photosensitive drum l7 whose exposure is started in step 71 and the leading edge of the paper P coincide. Then, the leading edge of the paper P is connected to the transfer device 20.
The transfer S24 is turned on at the timing of reaching (
Step ST73). Paper P transported in this way
, the toner image formed on the photosensitive drum 17 by the developing device 23 is transferred by the transfer device 20.

Furthermore, when the trailing edge of the paper P has completely passed through the paper feed cassette 22 and the next paper P can be fed, a print request for the second paper P is set and the attention signal ATN 1 is activated. It is output (changed from low level to high level) (step ST74). On the other hand, after a certain period of time has elapsed since the paper P was conveyed from the pair of aligning rollers 25, it is checked whether the paper ejection switch 49a1 or 49b is on (step ST75), and if it is not on, the paper P It is determined that the leading edge of the sheet has not reached the paper ejection roller 39 or 42, the print request is reset, the operator call status (jam) is set, and the ready signal PRDYO is set to 1 (step ST98).

And Ste Seop ST. Each device that has been turned on up to 74 is turned off in sequence (step ST99), and the
Return to T92. At this time, the power supply to the heater lamp 37a is cut off, that is, the ON/OFF control of the heater lamp 37a based on the temperature detected by the thermistor 37b is prohibited.

On the other hand, if the paper ejection switch 49a1 or 49b is on, the process waits until one page of the image data whose reception was started in step ST71 is captured (step ST76). After receiving the image data,
The data transfer status is reset, and the attention signal ATN1 is output (changed from low level to high level) (step ST77). Next, the aligning solenoid 310 is turned off at the timing when the trailing edge of the paper P passes the aligning roller pair 25 (step ST78).
, the aligning roller pair 25 stops. Furthermore, the transfer S24 is turned off at the timing when the trailing edge of the paper P passes the transfer device 20 (step ST79). Next, after a certain period of time has elapsed since the aligning solenoid 31b was turned off, it is checked whether the paper ejection switch 49a1 or 49b is turned off (step ST80).
. If it is not turned off, it is determined that the trailing edge of the paper P has not passed the paper discharge roller 39 or 42, and the process branches to step ST98, where jam processing is performed.

On the other hand, when the switch is off, it is determined that the paper P is normally ejected, the paper conveying status is reset, and the charging S22 is sequentially turned off (step ST8).
2), the developing bias S20 is turned off (step ST8).
3), the mirror motor 60 is turned off (step ST84).
), and the pre-exposure device 2l and the main motor 30
7 is turned off (step ST85). This completes the series of printing operations and returns to step ST62 again to enter the standby state.

Next, the printer control circuit 40 according to the above data transfer procedure
The operation of 0 will be explained with reference to the flowchart in FIG.

For example, if your laser printer is offline and
When the PU 401 determines that it is offline (step ST1), the host device 40
It is checked whether the printing process for the received data from 9 has been completed (step ST2). If it has not been completed, the process branches to step ST12 to continue the printing process.

On the other hand, if the printing process is completed, the above step ST1
, ST2 are repeatedly executed to create an idling state and wait for the laser printer to be placed on-line.

When the laser printer is brought online in this state, it is checked whether the data sent from the host device 409 is a command (step ST3), and if it is a command, it performs the operation corresponding to the command. (Step ST4) If it is not a command, the execution of the above command is skipped and the process proceeds to step ST5. The above commands, for example, define the attributes of the following data or control the printer without sending or receiving data. Next, it is checked whether the page buffer provided in the RAM 403 as a buffer for data reception is full (step ST5), and if it is not full, the data sent from the host device 409 is It is checked whether it is image data or not (step ST6). If it is not image data, the process returns to step STI and waits for command or image data to be received by repeating the above series of steps. In such a state,
When it is determined in step ST6 that image data has been received, the received image data is sequentially stored in the page buffer (step ST7). Next, it is checked whether storage for one page has been completed (step ST8).
, if not completed, the "data" lamp of the LED display 100b provided on the operation panel 100 starts blinking (step STIO). Then, step S
By returning to TI and executing the above series of steps, it waits until one page's worth of image data is accumulated in the page buffer. When it is determined that one page of image data has been stored by repeatedly executing the above series of steps, the "data" lamp is turned off (step ST
9) End the data reception process. And step S
The process moves to print processing after T12. Note that if it is determined in step ST5 that the page buffer is full, the data reception operation is stopped (step STII).
), in this case as well, the process moves to the print processing after step ST12. In this way, during the data reception operation, the "data" lamp is blinked to notify the operator.

Next, when one page of image data has been stored in the page buffer, it is checked whether the scan buffer provided on the video RAM 405 is full (
Step ST12). Here, if it is determined that the scan buffer is not full, the CPU 401 converts the image data of the character image stored in the page buffer to the video R as the scan buffer.
It is stored in AM405 (step ST13). On the other hand, if the scan buffer is full, the step ST
Skip I3.

Next, it is checked whether the print command has already been sent (step ST14), and if it has been sent, the following print command sending process (step STI 5,
Step ST19) is skipped and the process proceeds to step ST20. On the other hand, if the print request has not been sent, it is checked whether a print request has been sent (step ST15). If it is determined that no print request has been issued, it is determined that the print preparation on the engine side has not been completed, and the process returns to step STI and re-executes the above series of steps to issue a print request. wait for it to come. On the other hand, if it is determined that a print request has been issued, a print command is sent (step ST
19). Next, it is checked whether the VSYNC command has already been sent (step ST20). And V
When it is determined that a SYNC command has not been sent, it is checked whether a VSYNC request has been issued from the engine side (step ST21). And VSY
When it is determined that no NC request has been issued,
Returning to step STI, the process repeats the above series of steps and waits for a VSYNC request to be issued. Then, when it is determined in step ST21 that a VSYNC request has been issued, a VSYNC command is sent to the engine side (step ST22), and step STI
The process returns to the state of waiting for input of the horizontal synchronizing signal HSYNCO and video clock VCLKO.

In this state, in step ST20, VSY
When it is determined that the NC command has already been sent, it is checked whether the transfer of one page of image data has been completed (step ST26), and if the transfer of image data has not been completed, the scan buffer is The image data of the bit image stored in the horizontal synchronization signal HSYNC
It is sent to the engine side in synchronization with O and video clock VCLKO (step ST25). On the other hand, C.P.U.
Step 401 returns to step STI, and waits for the completion of transfer of one page of image data while executing the above series of steps again. When the transmission of the image data for one page is completed in this way, the process returns to step STI, and the printer control circuit 7l returns to its initial state and becomes ready to transfer the image data of the next page.

As mentioned above, when a paper jam occurs, that is, when the paper does not reach the fixing device, the fixing device continues to operate and the jam can be cleared. When a paper jam occurs, that is, when there is a possibility that the paper has reached the fixing device,
Since the fixing device stops operating and clears the jam, there is no risk of jammed paper catching fire, saving warm-up time when paper is jammed, and shortening the waiting time before printing is possible. I can do something.

[Effects of the Invention] As described above, according to the present invention, an image forming apparatus is provided which can shorten the warm-up time when an abnormality occurs in taking out an image forming medium from a storage means in which the image forming medium is stored. can be provided.

[Brief explanation of drawings]

The figures show an embodiment of the present invention; FIG. 1 is a configuration diagram showing the internal structure of a laser printer, FIG. 2 is an external perspective view of the laser printer, and FIG. 3 is a plan view showing the configuration of an operation panel. FIG. 4 is a block diagram showing the configuration of the main parts of the engine control section, FIG. 5 is a block diagram showing the structure of the engine control circuit, FIG. 6 is a block diagram showing the structure of the main parts of the printer control section, and FIG. The figure shows each signal that makes up the interface signal, FIG. 8 is a timing chart for explaining data path switching timing, FIG. 9 is a flowchart showing the operation of the engine control section, and FIG. 10 is a diagram showing the engine control section. 11 is a timing chart showing the operation of the printer control circuit. FIG. 11 is a flow chart showing the operation of the printer control circuit. l7... Photosensitive drum, 21... Charging device, 12...
...Leather exposure unit, 19...Development device, 20...
・Transfer device, 22, 30, 31...paper feed cassette (storage means), 24, 28, 29, 34...paper guide path,
25... Aligning roller pair, 23, 27, 32,
33... Outlet port-A, 36... Conveyor belt, 37...
... Fixing device (fixing means), 3L... Heat roller, 37a... Heater lamp, 37b... Thermistor, 38... Gate, 39, 42... Paper discharge roller pair,
40... paper output tray, 43... paper output tray, 48.
...Aligning switch (first detection means), 49
a, 49b... paper ejection switch (second detection means)
, 50, 51, 52, 53...Paper detector, 7 0
=． Engine control circuit, 71... printer control circuit,
l00...Operation panel, 302...Power supply device, 35
3...E2PROM, 401...CPU, 402.
ROM, 405... Video RAM, P... Paper (image forming medium).

Claims (1)

[Scope of Claims] A storage means in which an image forming medium is stored, a conveying means for taking out and conveying the image forming medium stored in the storing means, and an image forming medium conveyed by the conveying means. an image forming means for forming an image on a medium; a fixing means for fixing the image forming medium on which the image has been formed by the image forming means; a second detection means for detecting an abnormality in conveyance of the image forming medium by the conveyance means; A control means for continuing the operation of the fixing means and stopping the operation of the fixing means when an abnormality in conveyance of the image forming medium is detected by the second detection means. Forming device.