JPH03219986A - Image forming apparatus - Google Patents

Abstract

PURPOSE:To prevent that a fed paper creases or gets in the way by a method wherein a moved medium to be recorded is returned to a receiving means when no bit image data is sent even when a predetermined time is elapsed after the medium to be recorded is moved to the vicinity of the position of an image forming means. CONSTITUTION:When a printing command is received, a printing request is reset and a cassette paper feed clutch 309 is changed over by controlling a mechanism part driving circuit 306 to forwardly rotate a feed-out roller 23 and a feed roller 23a for a predetermined time and a paper P is taken out of a paper feed cassette 22 to be fed toward an aligning pair rollers 25. When a VSYN command is not received and a paper receiving command is received after a definite time is elapsed from the point of time when the paper P is fed, the mechanism part driving circuit 306 is controlled to change over the cassette paper feed clutch 309 and the feed-out roller 23 and the feed roller 23a are reversely rotated to return the paper P, fed to the aligning pair rollers 25, to the paper feed cassette 22.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) This invention is applicable to, for example, a laser printer that receives image data from an external device and prints a recorded image on paper from the received data. The present invention relates to an image forming apparatus.

(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 photosensitive drum, and a fixing device is further provided to receive paper from the peeling device. By driving each of the above-mentioned devices according to the rotational movement of the photosensitive drum, each of the above-mentioned image forming steps is executed, and an image is formed on the paper.

In such a laser printer, the control system includes an engine control section that controls the above-mentioned devices and controls operations for completing each of the above-mentioned image forming steps, and a printer control circuit that controls the operations of this engine control section. The engine control section and the printer control section are connected by sending and receiving commands and status.

For this reason, the paper conveyance process from the paper cassette is started by sending and receiving commands and status between the engine control unit and the printer control unit, so if the image processing time of the printer control unit is long, the engine Even if the control section is in a standby (ready) state, the engine control section is always forced to wait until the end of the process, so no similar consideration has been given to shortening the processing time for paper conveyance processing.

(Problems to be Solved by the Invention) As described above, even if the image forming means is in a ready state, the present invention provides that even if the image forming means is in a ready state, after the processing of the generating means for generating bit image data from image data from an external device is completed. This was done in order to eliminate the disadvantage that the movement process of the image forming medium starts, which takes a long time and image processing time.When image data is received from an external device, By moving the image forming medium in advance to a position close to the image forming means, and waiting for image data from the generating means for generating bit image data from the image data in the image forming means,
Even if the processing time in the generation means is long, the image forming medium is moved in advance, so the time required for the movement can be shortened, and the image forming apparatus can shorten the image processing time. The purpose is to provide.

[Configuration of the Invention (Means for Solving the Problems) The image forming apparatus of the present invention includes a receiving unit for receiving image data from an external device, and a generating unit for generating bit image data from the image data received by the receiving unit. means, an image forming means to which the bit image data generated by the generating means is sent and forms an image on a medium to be imaged in accordance with the bit image data; storage means in which the medium to be imaged is stored; a first processing means for moving the image forming medium to a position near the image forming means by taking out the image forming medium from the storing means and transporting the image forming medium when the image data is received by the receiving means;
When the bit image data is not sent from the generating means even after a predetermined period of time has passed after the image forming medium is moved by the first processing means, the image forming medium has been moved to the vicinity of the position of the image forming means. It is comprised of a second processing means for supplying the image forming medium to the storage means.

(Function) The present invention provides the following features: when receiving image data from an external device,
By taking out the image forming medium stored in the storage means by the conveying means and conveying it, the image forming medium is moved to the vicinity of the position of the image forming means. When no image data is sent, the image forming medium that has moved close to the position of the image forming means is supplied to the storage means.

(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; Optional devices 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 distributes the paper P or paper A after image formation into predetermined number of sheets are equipped with a laser. It is configured by being connected to a printer 1. 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 21, a peeling device 35, a fixing device 37,
In addition to process systems such as the cleaning device 45, a paper feed cassette 22, a delivery roller 23, a transport roller 23a, a pair of aligning rollers 25, a transport belt 36, a gate 38, a pair of paper discharge rollers 39, 42, etc. are provided. .

The laser optical system 12 includes a semiconductor laser oscillator (not shown) that generates laser light, a collimator lens (not shown) that corrects the laser light from this oscillator into parallel light,
A polygon mirror (rotating mirror) 13 as a rotating body having a portion of an octahedral mirror that reflects the laser beam from this lens for each scanning line, an f/θ lens 14, mirrors 15 and 16, and the polygon mirror described above. It is composed of a mirror motor 60 that rotates (drives) 13, and the like.

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 transmitted to the photoreceptor drum 10.
imaged on the surface of The photosensitive drum 17 rotates in the direction of the arrow shown in the figure, and the surface thereof is first charged by the charging device 18, and then exposed by the laser optical system 12 in accordance with an image signal. That is, the laser beam generated from the semiconductor laser oscillator is scanned at a constant speed from the left to the right of the photosensitive drum 17 as the polygon mirror 13 is rotated by the mirror motor 60, thereby creating an electrostatic charge on the surface of the photosensitive drum 17. A latent image is formed. This electrostatic latent image is made visible by applying toner 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 by the delivery roller 23 and the conveyance roller 23a, and passes through the paper guide path 24 to the aligning roller pair 2.
5, and is sent to the transfer section by this pair of rollers 25.

Also, to the transfer section, the paper P or the paper feed that is taken out one by one by the feed roller 32 from the paper feed cassette 30 in the multi-cassette feeder 2 and guided to the aligning roller pair 25 through the paper guide path 34.29. paper cassette 3
The paper P1 is taken out one by one by the delivery roller 33 from 1 and guided to the aligning roller pair 25 through the paper guide path 34.29, or the paper P1 is taken out one by one from the stacker 26 in the envelope feeder 3 by the delivery roller 27. The aligning roller pair 2 passes through the paper guide path 28 and 29.
The paper A1 guided to the aligning roller pair 25 and the paper P fed from the manual paper feed section 44 and guided to the aligning roller pair 25 through the paper guide path 29 are It is designed to be sent by

Then, the paper P or paper A sent to the transfer section is brought into close contact with the surface of the photoreceptor drum 17 at the transfer device 20, and the toner image on the photoreceptor drum 17 is transferred by the action of the transfer device 20. . This transferred paper P or paper A is peeled off from the photosensitive drum 17 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. 371, the transferred image is thermally 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 (user unit), and is configured to be able to be attached to and detached from the printer 1 independently. Further, in front of the pair of aligning rollers 25, there is an aligning switch 48 for detecting a paper feeding error to the transfer section by the pair of aligning rollers 25, etc., and in front of the pair of paper ejecting rollers 39, 42, an aligning switch 48 is provided. , are provided with paper ejection switches 49a and 149b for detecting paper ejection errors by the paper ejection roller pairs 39 and 42, respectively.

In addition, the paper feed cassette 22, 30, 31 has paper P
Paper detectors 50.5152 are arranged to detect the presence or absence of paper P in the paper feed cassettes 22, 30, and 31, respectively.

Further, above the laser optical system 12, 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 71 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 depending on the degree of function addition (for example, adding more types of fonts, kanji, etc.). Further functions can be added by inserting a function-adding IC card 517 into three IC card connectors 72 arranged on the front edge of the board 71. Furthermore, a connector (not shown) for connecting to a host 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 71 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 the mode, guidance messages, etc.
a. LED display 10 that lights up and displays various statuses with LEDs
0b, and a switch 100C for instructing various operations. 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, ``Service'' to request a service call, and ``Mode'' to indicate auto/manual.

The switch 100c includes, for example, a menu key, a value key, or a numeric keypad (not shown). The menu key is composed of two keys, "Next item" and "Previous item", and is displayed on the liquid crystal display 100.
The multiple menu information displayed on the left half of a is incremented each time the "Next Item" key is pressed, and decremented each time the "Previous Item" key is pressed, and these display operations are performed cyclically. It's about to be repeated. In addition, the above value keys are also “Next item” and “
It consists of the two keys in the previous item, and the LCD display 10
A plurality of pieces of value information corresponding to the menu information displayed on the left half of 0a are incremented each time the "Next item" key is pressed, and decremented each time the "Previous item" key is pressed, and each value is displayed on the right side of the liquid crystal display 100a. displayed in half,
These display operations are cyclically repeated.

The operator selects and instructs a desired operation 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, power supply voltages of +5V and +24V are output. The power supply voltage of +5V is supplied to the engine control circuit 70, and is further supplied to the printer control circuit 7 via this engine control circuit 70.
1.

On the other hand, for +24V power supply voltage, use cover switch 303.30
4 is sequentially supplied to the engine control circuit 70. The power is then supplied to the scanner control circuit 101, the high voltage power supply 305, and the mechanism drive circuit 306 through the engine control circuit 70, respectively. A semiconductor laser 90 and a mirror motor 9 are connected to the scanner control circuit 101.
2, from the mechanism drive circuit 306, there is a pre-exposure device 21, a main motor 307, a manual paper feed solenoid 308, a cassette paper feed clutch 309, and an aligning solenoid 31.
0 toner supply solenoid 311 and cooling fan 500
etc., and is used as a driving power source for these. The cassette paper feed clutch 309 is switched by the mechanism drive circuit 306 to
The delivery roller 23 and the conveyance roller 23a are configured to rotate forward or backward.

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 of the coupler. 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 supplying the AC power S1 to the heater lamp 37a. It is designed to turn on or cut off electricity. 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 cover or rear cover is opened, the switch 303.30
4 cuts off +24V, so that the semiconductor laser 90, mirror motor 60, high voltage power supply 305, main motor 307, solenoids 308, 310, 311, cassette paper feed clutch 309, cooling fan 500, heater lamp 37a, etc. are not operated. Even if the operator touches the inside of the apparatus main body 1 when the apparatus is stopped, there will be no problem.

FIG. 5 is a block diagram showing the configuration of the engine control circuit 70. In the figure, a CPU 350 controls the entire engine control section 300 and operates according to a control program stored in a 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 71.
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, S7, and S7 for controlling the mechanism drive circuit 306, the high voltage power supply 305, the scanner control circuit 101, and the heater lamp drive circuit, respectively.
S8 and S2 are output. The voltage signals S9 and S10 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 register 358 includes the vapor empty switch 320, manual feed switch 321, paper ejection switch 49a149b1 mounting switch 323, aligning switch 48, and paper detector 50.5L 52.53.
Status signals 511 SS12, S13, S14, S1 from
5.517 and the above +24V on/off status signal S
1G is being input. Further, the internal bus 359 connects the CPU 350, ROM 351, RAM 352, E
2PROM353, printer interface circuit 354
, laser modulation control circuit 355, output register 35B,
Data is exchanged between the A/D converter 357 and the input register 358.

The mechanism drive circuit 306 is provided with drive circuits for driving various motors, clutches, solenoids, etc., and on/off is controlled by a binary control signal S6 output from the output register 356. Ru. 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 7y:1
5001: +24 V is energized or cut off. The scanner control circuit 101 includes a semiconductor laser 9
0 and a drive circuit for the mirror motor 60 are provided.

The semiconductor laser 90 is turned on/off controlled by the laser modulation signal S5 output from the laser modulation control circuit 355, and the mirror motor 60 is controlled by the output register 35B.
On/off is controlled by a control signal S8 output from the control signal S8. Furthermore, the laser light detection sensor 3
A PIN diode is used for 12, and when the laser light a passes through this laser light detection sensor 312, a current proportional to the light energy flows. This current signal is used as the laser light detection signal S4 in the laser modulation control circuit 3.
55. Furthermore, high voltage power supply 3
From 05, high voltage signals of developing bias S20, charging S22, and transfer S24 are outputted to the developing bias power supplying section (not shown), the charging device 18, and the wire high voltage power supplying section (not shown) of the transfer device 20, respectively. . These on,
Off is the control signal S7 output from the output register 35B.
1.0.

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 a binary control signal output from the engine control circuit 70. It has become. 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 contains data related to the paper P such as a password, top margin, left margin, paper type, etc., which are checked when changing data.
Message information and the like for notifying the operator are stored. The RAM 403 is used as a page buffer for temporarily storing image data sent from the host device 409. Expanded memory 404
When the image data sent from the host device 409 is a large amount of data such as bitmap data, the above RA
The M403 is a large-capacity memory used when data for one page cannot be stored. Video RAM 4
05 stores image data developed into a bit image, and this output is sent to the serial-parallel converter circuit 4.
06. The serial-parallel conversion circuit 40B is connected to the video RAM 405.
The image data developed into a bit image and sent as parallel data is converted into serial data and sent to the engine control circuit 70.

The host interface 408 transfers data between the host device 409, which is composed of, for example, a computer or an image reading device, and the printer control unit 40, and has two types: a serial transfer line 410a and a parallel transfer line 410b. It is equipped with

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 71 and the engine control circuit 70. Connection circuit 4
Reference numeral 13 indicates an I
The power supply and signal line supplied to the IC card 517 are cut off to prevent data stored in the IC card 517 from being destroyed due to noise generated during insertion and removal.

The operation panel control circuit 407 controls displaying a guidance message on the liquid crystal display 100a of the operation panel 100;
The CPU controls the lighting, turning off, and blinking of the LED display 100b, or the data input from the switch 100c.
401, etc. Further, the internal bus 412 includes the CPU 401, ROM 402,
RAM403, expansion memory 4o4, video RAM40
5. A bus that exchanges data among the operation panel control circuit 4o7, host interface 408, engine interface 4111, and connection circuit 413.

The IC card 517 also includes a non-volatile memory, such as a static RAM with battery backup, E2
It is composed of a PROMSEPROM, a mask ROM, etc. These IC cards 517 include
For example, character fonts, emulation programs, etc. are stored.

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 7o
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 engine is at a high level (not busy), the DO-D7 is switched from the engine control circuit 7o to the direction in which the signal is sent to the printer control circuit 71. The status is output on Do-D7. This allows the printer control circuit 71 to read the status.

On the other hand, when the printer control circuit 71 sends a command, when the busy signal BSYO is at a high level (not busy) and the bus direction signal I) IR is set at a high level, Do-D7 is sent from the printer control circuit 71 to the engine control circuit 7o. The command is switched to transmit a signal to DO-D7.
is output above. When the strobe signal 5TBO is set to a low level in this state, the engine control circuit 70 reads the command on DO-D7 while the strobe signal 5TBO 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 5TBO to a high level and ends the command transmission. Then, when the command processing in the engine control circuit 70 is completed, the busy signal BSYO is returned to the 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 7o. Furthermore, the status on the data bus Do-D7 does not change immediately when a state change occurs in the engine control unit 300, but is updated only when the status is returned in response to a command received after the state 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 one page of image data has been received, and is reset to a low level when an attention reset command is received. When the attention signal ATN1 changes from a low level to a high level, the printer control circuit 71 sends an attention reset command onto the data bus DO-D7, resets the attention signal ATN1, and then outputs an attention reset command onto the data bus DO-D7. −
It is now possible to read the status on D7 and know the changed basic status. In addition, the above basic status is also output on the data bus 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 ready 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 print operation by the engine control unit 300 is possible. It is.

System clear signal 5CLRI is printer control circuit 71
200~ after +5V rises with the reset signal of
The level remains high for 500 m5ec, during which the printer control circuit 71 enters the reset state.

The prime signal pdIMEo is a reset signal to the engine control circuit 70, and while this signal is at a low level, the busy signal SYO is at a low level, the ready signal PRDYO is at a high level, and the engine control circuit 70 is in a predetermined initial state. return.

The horizontal synchronization signal H3YNCO is a signal generated every time one line is scanned by the laser exposure unit 22, and is a signal generated every time the laser exposure unit 22 scans one line.
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 H3Y.
This is a synchronization clock for inputting one line of video data (image data) VDO to the engine control circuit 70 following NcO, and is output in a number corresponding to the effective print width of 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.

In response to this and the video data VDO, the laser exposure unit 22 performs exposure scanning on the photosensitive drum 17 to form a latent image on the photosensitive drum 17. In addition,
When the video data VDO is at a low level, it is visualized on the paper P as a dot image.

Next, the operation of the printer control circuit 400 according to the data transfer procedure in the above configuration will be explained with reference to the flowcharts in FIGS. 9(a) and 9(b).

For example, now a laser printer is offline and C
When the PU 401 determines that it is in the offline state (step 5T1), the host device 40
It is checked whether the printing process for the received data from 9 has been completed (step 5T2). If it has not been completed, the process branches to step 5T12 to continue the printing process.

On the other hand, if the printing process is completed, the above step STI
, Sr1 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 5T3), and if it is a command, it performs the operation corresponding to the command. (Step 5T4) If it is not a command, the execution of the above command is skipped and the process proceeds to step ST5. The above command is
For example, it defines the attributes of the following data or controls a printer that does not involve 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 5T5), and if it is not full, the data sent from the host device 409 is used as an image. It is checked whether it is data (step 5T6). and,
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 this 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 5T7).

Also, it is checked whether a print request has been issued (step 5T30). 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 step S
Return to the TI and re-execute the above series of steps to wait for a print request to be issued. On the other hand, if it is determined that a print request has been issued, it is determined that the engine control unit 300 is ready for printing, and a print command is sent (step ST31).
).

Next, it is checked whether the storage for one page has been completed (step 5T8), and if the storage has not been completed, the operation panel 1
The "data" lamp of the LED display 100b provided at 00 starts blinking (step 5T10). Next, the process returns to step ST1 and executes the series of steps described above, thereby waiting until image data for one page is accumulated in the page buffer. When it is determined that storage of image data for one page has been completed by repeatedly executing the above series of steps, the "data" lamp is turned off, step 5T9), and the data reception process is ended.

Then, the process moves to the print processing after step 5T12.

Note that if it is determined in step ST5 that the page buffer is full, the data reception operation is stopped (step 5T11), and in this case as well, the process moves to the printing process from step 5T12. In this way, during the data reception operation, the "data" lamp is blinked to notify the operator.

Next, when one page's worth 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 5T12). Here, if it is determined that the scan buffer is not full, the CPU 401 converts the image data stored in the page buffer into bit image data of a character image and stores it in the video RAM 405 as a scan buffer ( Step 5
T13).

On the other hand, if the scan buffer is full, step 5T13 is skipped.

Also, when it is determined that the expansion into a bit image in step 13 above is not performed normally (step 5T33)
, or when the transmission of image data stops while image data from the host device 409 is being stored in step 7 (step 5T32), the CPU 401
A paper storage command is sent to the engine control unit 300 (step 5T34), and the bit image development process or data reception process is ended.

Next, if the bit image expansion process is performed normally, V
It is checked whether the SYNC command has been sent (step 5T20). Then, when it is determined that the VSYNC command has not been sent, the VSYNC command is sent from the engine side.
It is checked whether an NC request has been issued (step 5T21). When it is determined that no vSYNC request has been issued, the process returns to step ST1 and the above series of steps are executed again.
Wait for a request to be made. And Stehesob 5
When it is determined in T21 that a VSYNC request has been issued, a VSYNC command is sent to the engine (step 5T22), and the process returns to step ST1 to wait for the horizontal synchronization signal H3YNCO and video clock VCLKO to be input. Transition.

In this state, in step 5T20 above, 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 5T26), and if the transfer of image data has not been completed, The image data of the bit image stored in the scan buffer is sent to the horizontal synchronization signal H9YNCO.
and is sent to the engine side in synchronization with the video clock VCLKO (step 5T25). On the other hand, CPU 40
Step 1 returns to step STI and waits for the completion of transfer of one page of image data while executing the series of steps described above again. When the transmission of the image data for one page is completed in this manner, the process returns to step ST1, and the printer control circuit 71 returns to its initial state and becomes ready to transfer the image data of the next page.

Next, the operation of the engine control section 300 of the laser printer will be explained with reference to the flowchart shown in FIG.

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 71 to receive a reset signal 5CLRI (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 0m5ee, 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 the RAM 352 is initialized (step 5T50). Next, input register 3
The status of each switch is read in step 58, and it is checked whether an operator call condition such as paper jam, cover oven, process unit 4 installation, vapor empty, etc. has occurred (step 5T51). Here, if an operator call has occurred, it is checked whether only vapor empty has occurred (step 5T52), and if an operator call other than vapor empty has occurred, the process returns to step 5T51 and the operator Wait until the call state is released. On the other hand, when only vapor empty occurs in step 5T52, or when no operator call occurs in step 5T51, heating of the fixing device 37 is started (step 5T53). Next, to initialize the electrophotographic process, the main motor 307 and pre-exposure device 21 are turned on (step 5T54), and then charging S22 is turned on sequentially at time intervals determined by the program (step 5T54). 5T55), and the developing bias S20 is turned on (step 5T56).

In this state, it is checked whether a certain period of time (approximately 30 seconds) has elapsed (step 5T57), and until the certain period of time has elapsed, it is checked whether the cover has opened (step 5T90). Then, when a cover open occurs, in steps 5T53 to 5 above,
Turn off each output turned on in T56 Step 5T91
), the process returns to step ST51. On the other hand, step 5T
When it is confirmed in step 57 that a certain period of time has elapsed, the charging S22 is turned off (step 5T58), then the developing bias S20 is turned off in sequence at the timing determined by the program (step 5T59), and the main motor 307 is turned off.
, and the pre-exposure device 21 is turned off (step 5T60
). Through the series of operations from step 5T53 to step S60, the warming-up operation of the image forming apparatus is completed.

Then, the ready signal PRDYO is output (changed from high level to low level), a print request is set on the data bus Do-D7, and the attention signal ATNI is output (changed from low level to high level).
and becomes ready for printing (step 5T61). Note that the constant d device 37, which has started heating in step 5T53, is in a temperature state sufficient for the fixing operation in the process leading to step 5T61.

Further, when an operator call occurs, its contents are outputted onto the data bus as operator call status.

On the other hand, in the state of step ST61, the printer control circuit 7
1 can recognize the print request by sending the above-mentioned attention reset command to reset the attention signal ATN1 to a low level, and then reading the status on the data bus according to the above procedure. In FIGS. 10(a) to 10(e), the attention reset command, the process of resetting the attention signal ATN 1 (changing from high level to low level), and the printing operation for the second sheet are omitted.

Next, it is checked whether a print command has been received (step 5T62). If a print command is not received, it is checked whether an operator call has occurred (step 5T92), and if 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 5T94). Then, it is checked whether or not cover opening has occurred among the causes of the operator call (step 5T95), and if cover opening has occurred, the process returns to step ST51. On the other hand, if the cover has not been opened, the process returns to step 5T92 and waits for the operator call to be released. In step 5T92,
When no operator call occurs, ready signal P
It is checked whether RDYO is low level (step 5T93), and if this signal is low level, step 5
The process returns to T62 and waits for a print command. If the level is high, the not-ready state has already been reached in step 5T94, so the process returns to step ST61 and the ready state is returned again. That is, the above steps 5T62→5T92-3
The flow of T93-5T62 is a state of waiting for a print command, a so-called standby state.

When it is determined in step 5T62 that a print command has been received, the print request is reset and a series of print operations are performed. That is, as shown in FIG. 10, first, the mirror motor 60 is turned on (step 5T63), then the main motor 307 and the pre-exposure device 21 are turned on in sequence at predetermined time intervals (step 5T64), and the charging S22 , the cassette paper feed clutch 3 by controlling the mechanism drive circuit 306.
09 is switched, the feed roller 23 and the conveyance roller 23a are rotated forward, and the basic status is set to ``paper conveyance'' (step 5T65). Further, the developing bias S20 is turned on (step 5T66), and by switching the cassette paper feed clutch 309, the feed roller 2
3. The rotation of the transport roller 23a is stopped (step 5)
T67).

Here, by controlling the mechanism drive circuit 306, the cassette paper feed clutch 309 is switched and the delivery roller 23,
The conveyance roller 23a is rotated in the forward direction for a predetermined period of time, and the paper P is taken out from the paper feed cassette 22 and conveyed toward the aligning roller pair 25 by the rotation of the delivery roller 23 and the conveyance roller 23a. Then, after a certain period of time has elapsed since the paper P was fed, it is checked whether or not the aligning switch 48 is on (step 5T68).

When the aligning switch 48 is not turned on, it is determined that the paper P has not reached the aligning roller pair 25, and the paper is handled as a paper jam.

That is, the operator call status (jam) is set and the ready signal PRDYO is set to 1 (step 5T96). Furthermore, each device that was turned on in the process from step 5T63 to step 5T66 is turned off in sequence at a timing determined by the program (step 5T97), and the process returns to step 5T92 to wait for the jam to be cleared.

Next, the vSYNC request is set, and the attention signal ATN1 is output (changed from low level to high level) (step ST69). Then, it is checked whether a paper storage command has been received (step 5T100), and it is checked whether a VSYNC command has been received (step 5T70).
). When a paper storage command is received, the mechanism unit drive circuit 306 is controlled to switch the cassette paper feed clutch 309 to reversely rotate the delivery roller 23 and transport roller 23a, and the paper is transported to the aligning roller pair 25. Step 5T10 of returning the paper P to the paper feed cassette 22
1) Each device turned on in the process from step 5T63 to step 5T66 is turned off in sequence at a timing determined by the program (step 5T102), and the process returns to step 5T92.

Further, when a VSYNC command is received, the vSYNC request is reset, data is being transferred or not, and laser exposure is started. That is, the horizontal synchronization signal H8YNCO and video clock VCLKO
While transmitting the video data VDO, reception of the video data VDO is started, and an image pattern based on the video data VDO is exposed on the photosensitive drum 17 (step 5T71). Note that until step 5T71, the pair of aligning rollers 25 remains stopped, so the sheet 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 5T72), 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 connects the leading edge of the image on the photoreceptor drum 17 and the paper P whose exposure was started in step ST71.
It is turned on at the timing when the tip of the

Then, the transfer S24 is turned on at the timing when the leading edge of the paper P reaches the transfer device 20 (step 5T7).
3). The toner image formed on the photosensitive drum 17 by the developing device 19 is transferred to the sheet P transported in this manner by the transfer device 20 . Furthermore, the trailing edge of the paper P completely passes through the paper feed cassette 22, the next paper P is automatically fed, a print request for the second paper P is set, and an attention signal AT
N1 is output (changed from low level to high level) (step 5T74). On the other hand, after a certain period of time has elapsed since the paper P was conveyed from the aligning roller pair 25, it is checked whether the paper ejection switch 49a1 or 49b is on (step 5T75), and if it is not on, the paper P It is determined that the leading edge of the paper has not reached the paper ejection roller unit 42, and the print request is reset.
The operator call status (jam) is set and the ready signal PRDYO is set to 1 (step 5T98). Then, each device that has been turned on up to step 5T74 is turned off in sequence (step 5T99).
, return to step 5T92. On the other hand, the paper ejection switch 49a
1 or 49b is on, step 5T above
The process waits until one page of image data, which has started receiving in step 71, is captured (step 5T76). When the reception of the image data is completed, the data transfer status is reset and the attention signal ATNI is output (changed from low level to high level) (step 5T77).

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 5T78), and the aligning roller pair 25
stops. Further, the transfer S24 is turned off at the timing when the trailing edge of the paper P passes the transfer device 20 (step 5T79). Next, after a certain period of time has passed since the aligning solenoid 310 was turned off, the paper ejection switch 49
It is checked whether a or 49b is off (step 5T80). If it is not turned off, it is determined that the trailing edge of the paper P has not passed the paper discharge roller unit 42, and the process branches to step 5T98, where jam processing is performed. On the other hand, when the switch is off, it is determined that the paper P is being ejected normally, the paper conveying status is reset, and the charging S22 is sequentially turned off (step 5T82) and the developing bias S20 is turned off. (step 5T83), the mirror motor 60 is turned off (step 5T84), and the pre-exposure device 21 and main motor 307 are turned off (step 5T85), completing a series of printing operations and returning to step 5T62 again to enter the standby state. become.

As described above, when image data is received from the host device, the feed roller is rotated to brie-feed the paper in the paper feed cassette to the aligning switch. As a result, the processing time of the printer control circuit, that is, the time spent waiting for bit image development, is used to take out the paper from the paper feed cassette and move it to the aligning switch in advance, reducing paper feeding time. As a result, image processing time can be shortened.

Furthermore, even if the processing time of the printer control circuit follows the processing speed of the engine control circuit, the paper feeding time during first printing can be shortened.

In addition, if the reception process stops midway or the bit image development process is not performed normally, the paper that was previously fed is returned to the original paper cassette and stored, so the paper cannot be fed. The paper that was being fed becomes wrinkled, or the paper that was being fed does not get in the way when changing the paper size.

[Effects of the Invention] As described above, according to the present invention, when starting to receive image data from an external device, the image forming medium is moved in advance to the front of the image forming means, and the image forming means By waiting for data from the generation means that generates bit image data for image formation, the movement of the image forming medium is performed in advance even if the processing time in the generation means is long. It is possible to provide an image forming apparatus that can shorten the image processing time.

[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 constituting the interface signal, Fig. 8 is a timing chart for explaining the data bus switching timing, Fig. 9 is a flowchart showing the operation of the printer control circuit, and Fig. 10 is the engine control section. 3 is a flowchart showing the operation of FIG. 17... Photosensitive drum, 21... Charging device, 12...
...Laser exposure unit, 19...Developing device, 20.
... Fixing device, 22 ... Paper feed cassette, 23 ... Sending roller, 23a ... Conveyance roller pair, 25 ... Aligning roller pair, 48 ... Aligning switch,
70... Engine control circuit, 71... Printer control circuit, 300... Engine control section, 306... Machine rear drive circuit, 309... Cassette paper feed clutch, 40
0...Printer control unit, 401...CPU, 402
ROM, 403 RAM, 405 Video RAM 5P Paper (image forming medium). 3rd Figure 582- Figure 10 Figure (a) Figure 0 (b) Figure 10 (d) Figure 0 (e)

Claims (1)

[Claims] Receiving means for receiving image data from an external device, generation means for generating bit image data from the image data received by the receiving means, and bit image data generated by the generation means for transmitting. an image forming means for forming an image on a medium to be imaged corresponding to the bit image data; a storage means in which the medium for image formation is stored; a first processing means for moving the image forming medium to a position near the image forming means by taking out the image forming medium from the storage means and transporting the image forming medium; and a first processing means for moving the image forming medium by the first processing means. a second process of supplying the image forming medium that has moved close to the position of the image forming means to the storing means when the bit image data is not sent from the generating means even after a predetermined period of time has elapsed; means and
An image forming apparatus comprising: