JP2001232853A - Image forming apparatus, method of controlling signal and memory medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus, a signal controlling method and a memory medium wherein a horizontal synchronizing signal and a vertical synchronizing signal are transmitted in a single signal line so that the number of synchronizing signals necessary for an image forming operation can be reduced and a load of an operation by a video controller can be reduced. SOLUTION: This image forming apparatus comprises the video controller 103 for executing an image processing, a TOP sensor 119 for detecting a top end of a paper sheet and an engine controller 105. The engine controller 105 performs the controlling wherein the horizontal synchronizing signal of image data in a first pulse width is transmitted to the video controller 103 in synchronism with a beam position pulse signal outputted from a waveform shaping circuit 20 and the controlling wherein the horizontal synchronizing signal is changed to one in a second pulse width to be outputted based on the detection of the top end of the paper sheet by the TOP sensor 119 and then the vertical synchronizing for start of the image data is transmitted to the video controller 103.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, a signal control method, and a storage medium. More particularly, the present invention relates to an image processing means for generating pixel data and a communication means for communicating image forming means for forming an image on a recording medium. TECHNICAL FIELD The present invention relates to an image forming apparatus, a signal control method, and a storage medium having a configuration for connection via a memory.

[0002]

2. Description of the Related Art Conventionally, there is an image forming apparatus configured to convey a sheet as a recording medium to an image forming position inside the apparatus, transfer a toner image to the sheet, and form an image. Conventional image forming apparatuses include, for example, FileNO. As described in US Pat. No. 145,915, the apparatus has two synchronization signals, that is, a horizontal synchronization signal in the main scanning direction and a vertical synchronization signal in the sub-scanning direction, and is configured to transfer a toner image on paper in accordance with the same.

[0003]

However, the above-mentioned prior art has the following problems. That is, the above-described conventional image forming apparatus requires two synchronization signals in the main scanning direction and the sub-scanning direction, and an image processing video controller provided in the image forming apparatus uses There is a problem that extra processing is required for synchronization.

[0004] The present invention has been made in view of the above points, and realizes transmission of a horizontal synchronizing signal and a vertical synchronizing signal through one signal line, thereby realizing a synchronizing signal necessary for an image forming operation. It is an object of the present invention to provide an image forming apparatus, a signal control method, and a storage medium capable of reducing the number of the image forming apparatuses and reducing the processing load of a video controller.

[0005]

According to an aspect of the present invention, there is provided an image forming apparatus for forming an image on a recording medium such as paper based on optical scanning by an optical system in accordance with image data. Image processing means for transmitting image data to an image forming system, position detecting means for detecting a scanning reference position of a light beam scanned from the optical system, and synchronizing with a beam position pulse signal output from the position detecting means. And sends a horizontal synchronization signal of the image data to the image processing means for the first time.
Transmitting means for transmitting the recording medium at a pulse width of; a conveying means for conveying the recording medium to the image forming position; a conveying start means for causing the conveying means to start conveying the recording medium based on an instruction of the image processing means; A leading edge detecting means for detecting a leading edge of the medium in the transport direction; and starting the image data to the image processing means by changing the horizontal synchronization signal to a second pulse width based on the leading edge detection by the leading edge detecting means and outputting the second pulse width. And control means for transmitting the vertical synchronization.

According to another aspect of the present invention, a light reflecting means for reflecting light, a driving means for rotating the light reflecting means, and a light beam reflected by the light reflecting means are condensed. Light scanning means comprising a light condensing means,
A light emitting means for emitting a light beam toward the light reflecting means of the light scanning means; a light modulating means connected to an input of the light emitting means for modulating the intensity of the light beam; and a light modulating means connected to the input of the light modulating means Receiving means for receiving the image data from the image processing means and transmitting an image signal to the light modulation means; changing means for changing a pulse length of the horizontal synchronizing signal; photosensitive means having a photosensitive function; A charging unit for charging the unit, and a charged image formed on the surface of the photosensitive unit by scanning the surface of the photosensitive unit charged by the charging unit with an output beam of the optical scanning unit to form a visible image of a developer. And a transfer unit for transferring the visible image converted by the developing unit to a recording medium.

According to a third aspect of the present invention, the transmitting means outputs information indicating that the horizontal synchronizing signal is non-output during a period in which the horizontal synchronizing signal is non-output. It is characterized by the following.

In order to achieve the above object, the invention according to a fourth aspect has a rear end detecting means for detecting a rear end of the recording medium in a conveying direction, and the control means includes a rear end detecting means for detecting the rear end of the recording medium. By outputting the horizontal synchronization signal of the second pulse width or the third pulse width based on the edge detection, the image processing means is notified of the vertical synchronization of the end of the image data.

In order to achieve the above object, the invention according to claim 5 is applicable to a printer that forms an image on a recording medium such as paper based on optical scanning by the optical system in accordance with image data received from an external device. It is characterized by the following.

In order to achieve the above object, the invention according to claim 6 is applicable to a copying machine which forms an image on a recording medium such as paper based on optical scanning by the optical system in accordance with image data read from a document. It is characterized by the following.

In order to achieve the above object, the invention according to claim 7 is a signal control method applied to an image forming apparatus for forming an image on a recording medium such as paper based on optical scanning by an optical system according to image data. An image processing step of sending image data to an image forming system; a position detecting step of detecting a scanning reference position of a light beam scanned from the optical system; and a beam position pulse signal output from the position detecting step. A transmitting step of synchronously transmitting a horizontal synchronization signal of the image data to the image processing step with a first pulse width, a transporting step of transporting a recording medium to an image forming position, and A transport start step of starting transport of the recording medium in the transport step, a leading edge detection step of detecting a leading edge of the recording medium in the transport direction, and a leading edge detection step based on the leading edge detection by the leading edge detection step. Characterized by a control step of transmitting the horizontal synchronizing signal the image processing start of the vertical synchronization of the image data in step by change output to the second pulse width.

In order to achieve the above object, the invention according to claim 8 provides a light reflection step of reflecting light by light reflection means.
A light scanning step including a driving step of rotating the light reflecting means and a focusing step of focusing the light beam reflected in the light reflecting step, and a light emitting step of emitting a light beam toward the light reflecting means. A light modulation step of performing intensity modulation of a light beam; a reception step of receiving the image data from the image processing step and transmitting an image signal to the light modulation step; and a changing step of changing a pulse length of the horizontal synchronization signal. A photosensitive step of performing exposure by a photosensitive unit, a charging step of charging the photosensitive unit, and scanning the surface of the photosensitive unit charged in the charging step with an output beam of the optical scanning step. And a transfer step of transferring the visible image converted in the developing step to a recording medium by converting a charged image formed on the surface of the developer into a visible image of a developer.

In order to achieve the above object, the invention according to claim 9 is that, in the transmitting step, information indicating that the horizontal synchronizing signal is non-output is output during a period in which the horizontal synchronizing signal is non-output. It is characterized by the following.

In order to achieve the above object, the invention according to a tenth aspect has a trailing edge detecting step of detecting a trailing edge of the recording medium in a conveying direction, and the control step includes a step of detecting the trailing edge by the trailing edge detecting step. Second pulse width or third pulse width based on edge detection
The vertical synchronization of the end of the image data is transmitted to the image processing step by outputting the horizontal synchronization signal having a pulse width of?

In order to achieve the above object, the invention according to claim 11 is applicable to a printer that forms an image on a recording medium such as paper based on optical scanning by the optical system according to image data received from an external device. It is characterized by the following.

To achieve the above object, the invention according to claim 12 is applicable to a copying machine that forms an image on a recording medium such as paper based on optical scanning by the optical system in accordance with image data read from a document. It is characterized by the following.

In order to achieve the above object, the invention according to claim 13 executes a signal control method applied to an image forming apparatus for forming an image on a recording medium such as paper based on optical scanning by an optical system according to image data. A storage medium readable by a computer storing a program to execute, wherein the signal control method includes an image processing step of controlling image data to be sent to an image forming system, and a light beam scanning process performed by the optical system. A position detection step of controlling to detect a scanning reference position; and a horizontal synchronization signal of the image data at a first pulse width to the image processing step in synchronization with a beam position pulse signal output from the position detection step. A transmitting step of controlling to transmit, a transporting step of controlling to transport a recording medium to an image forming position, and the image processing A conveyance start step for controlling the conveyance step to start conveyance of the recording medium based on an instruction of the step, a front end detection step for controlling to detect a front end of the recording medium in the conveyance direction, and the front end detection step A control step of controlling the image processing step to transmit vertical synchronization of the start of image data to the image processing step by changing the horizontal synchronization signal to a second pulse width and outputting the same based on the detection of the leading edge. I do.

In order to achieve the above object, the invention according to claim 14 is a light reflecting step for controlling light to be reflected by the light reflecting means, a driving step for controlling the light reflecting means to rotate, and the light step. A light scanning step comprising a light collecting step of controlling to collect the light beam reflected in the reflection step, and a light emitting step of controlling to emit a light beam toward the light reflecting means,
A light modulation step of controlling to perform intensity modulation of a light beam, a reception step of receiving the image data from the image processing step, and controlling to transmit an image signal to the light modulation step, A changing step of controlling to change the pulse length, a photosensitive step of controlling to perform exposure by a photosensitive unit, a charging step of controlling to charge the photosensitive unit, and the charging step performed by the charging step. A developing step of scanning the surface of the photosensitive means with the output beam of the light scanning step to convert a charged image formed on the surface of the photosensitive means into a visible image of a developer; and A transfer step of controlling the visible image to be transferred to a recording medium.

In order to achieve the above object, in the invention according to claim 15, in the transmitting step, information indicating that the horizontal synchronizing signal is non-output is output during a period in which the horizontal synchronizing signal is non-output. Control as described above.

In order to achieve the above object, an invention according to a sixteenth aspect of the present invention includes a trailing edge detecting step for detecting a trailing edge of the recording medium in the transport direction, wherein the controlling step includes the trailing edge. Outputting the horizontal synchronizing signal having a second pulse width or a third pulse width based on the trailing edge detection by the detecting step to control the image processing step to transmit the vertical synchronization of the end of the image data to the image processing step. And

To achieve the above object, the invention according to claim 17 is applicable to a printer that forms an image on a recording medium such as paper based on optical scanning by the optical system in accordance with image data received from an external device. It is characterized by the following.

To achieve the above object, the invention according to claim 18 is applicable to a copying machine that forms an image on a recording medium such as paper based on optical scanning by the optical system in accordance with image data read from a document. It is characterized by the following.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[First Embodiment] FIG. 2 shows a first embodiment of the present invention.
FIG. 2 is a configuration diagram illustrating a configuration example of a laser beam printer according to an embodiment. The laser beam printer according to the first embodiment of the present invention generally includes a controller unit 100 and an engine unit 102. Controller unit 10
0 is the host I / F circuit 101 and the video controller 1
03, an operation panel 104, and an engine unit 10
2 is an engine controller 105, a laser driver 1
06, semiconductor laser 107, polygon mirror 108, mirror 109, primary charger 111, photosensitive drum 112, developing device 113, transfer charger 114, cleaning device 11
5, a fixing device 116, a TOP sensor 119, a paper feed cassette 120, and a paper feed roller 121.

The above configuration will be described in detail together with the operation. In the controller unit 100, the host I / F circuit 101
Image information transmitted from a host computer (not shown) connected to the laser beam printer is input. The video controller 103 performs image processing such as converting image information input from the host computer via the host I / F circuit 101 into pixel data, and performs image processing.
Send to 2. As will be described in detail below, the engine unit 102 forms an image based on pixel data, and forms an image on a sheet as a recording medium. Controller unit 100
The video controller 103 and the engine controller 105 of the engine unit 102 are connected by an interface called a video interface.

The video controller 103 develops an electric signal, which is code data (image information) input from the host computer via the host I / F circuit 101 into a dot image as described above, and
After storing the data in the internal memory, the video signal is transmitted as a video signal to the engine unit 102 via the video interface. The operation panel 104 includes an operation unit for performing various settings and a display unit for performing various displays.

In the engine unit 102, the engine controller 105 determines whether the temperature of the fixing unit 116 has become appropriate after the power of the laser beam printer is turned on, whether the paper is loaded in the paper cassette 120, and the like. Is checked to determine whether or not printing is possible with the laser beam printer. When the laser beam printer is ready for printing, the controller 100
The video controller 103 receives an instruction to start printing from the engine controller 105 of the engine unit 102 as necessary, and
Starts the printing operation.

From the paper feed cassette 120 to the paper feed roller 121
When the leading edge of the sheet reaches the TOP sensor 119, the engine controller 105 of the engine unit 102 transmits vertical synchronization to the video controller 103 of the controller unit 100 when the leading edge of the sheet reaches the TOP sensor 119. The video controller 103 of the controller unit 100 synchronizes the image signal (BD signal) with the BD signal and outputs the image signal (BD signal) to the engine controller 105 of the engine unit 102.
To send to. The video signal input to the engine controller 105 is sent to a laser driver 106, where ON / OFF of the semiconductor laser 107 is controlled.

The laser light 110 emitted from the semiconductor laser 107 is deflected by the polygon mirror 108 to become main scanning light in the longitudinal direction of the photosensitive drum 112, and is projected on the photosensitive drum 112 via the mirror 109.
The photosensitive drum 112 rotates in the direction of the arrow in the drawing, and is primarily charged by the primary charger 111, and then the laser beam 110 is turned on.
Upon receiving the exposure corresponding to / OFF, an electrostatic latent image is formed on the surface of the photosensitive drum 112. Then, after the colored charged particles (hereinafter, referred to as toner) are applied by the developing device 113 to obtain a visualized image, the visualized image is transferred onto a sheet as a recording medium by the transfer charger 114. The transfer residual toner is wiped off from the surface of the photosensitive drum 112 by the cleaning device 115, and the photosensitive drum 112 prepares for the next image forming process.

On the other hand, a sheet as a recording medium on which an unfixed toner image is placed is inserted between the heater 117 and the pressure roller 118 of the fixing unit 116, and a permanent fixed image is obtained. It is discharged out of the machine along the direction of the arrow. When the trailing edge of the sheet passes through the conveyance path near the TOP sensor 119, the video controller 103 of the controller unit 100 stops sending the video signal to the engine controller 105 of the engine unit 102. Arrows in the drawing indicate the feeding trajectory of the sheet fed from the sheet feeding cassette 120 and conveyed by the conveying mechanism.

FIG. 1 is a block diagram showing a configuration example of a control system of the laser beam printer according to the first embodiment of the present invention. The control system of the laser beam printer according to the first embodiment of the present invention includes a video controller 103, a BD
Engine controller 105 having signal generation circuit 32 / CPU 33, laser driver 106, semiconductor laser 1
07, polygon mirror 108, photosensitive drum 112, TO
P sensor 119, waveform shaping circuit 20, scanner motor 2
1, a coupling lens 22, an fθ lens 23, a photodiode 24, and an amplifier 25.

The above configuration will be described in detail together with the operation. The video controller 103 performs control for transmitting the video signal 31 to the laser driver 106 and the like. The BD signal generation circuit 32 of the engine controller 105 generates a BD signal 34. The CPU 33 of the engine controller 105
Activating the scanner motor 21 and the semiconductor laser 10
7, the control to determine whether the cycle of the waveform pulse 30 input from the waveform shaping circuit 20 to the BD signal generating circuit 32 is normal, and to start the printing operation when the cycle of the pulse is normal. Control for forcibly stopping the semiconductor laser 107, control for detecting the leading edge of the sheet based on a signal input from the TOP sensor 119, and transmitting vertical synchronization to the video controller 103 are performed. The laser driver 106 turns on / off the semiconductor laser 107
Perform control. The semiconductor laser 107 is a polygon mirror 1
A laser beam is emitted to the mirror surface 08.

The scanner motor 21 is a polygon mirror 1
08 is rotated at a predetermined speed. Polygon mirror 108
Reflects the laser beam incident from the semiconductor laser 107 via the coupling lens 22 and irradiates the surface of the photosensitive drum 112 via the fθ lens 23. Photodiode 2
4 outputs to the amplifier 25 a signal based on the laser light periodically emitted from the polygon mirror 108. Amplifier 2
5 amplifies the output signal from the photodiode 24,
Output to the waveform shaping circuit 20. The waveform shaping circuit 20 shapes the output signal from the amplifier 25 into a pulse waveform 30 (beam position pulse signal), and outputs it to the BD signal generation circuit 32 of the engine controller 105.

FIG. 6 is an explanatory view showing a conceptual example in which the program and related data of the present invention are supplied from a storage medium to the apparatus. The program and related data of the present invention are stored in a storage medium drive insertion slot 6 provided in a device 62 such as a computer by inserting a storage medium 61 such as a floppy disk or a CD-ROM.
3 to be supplied. Thereafter, the program and related data of the present invention are temporarily installed on the hard disk from the storage medium 61 and loaded into the RAM from the storage medium 61, or directly loaded into the RAM without being installed on the hard disk, so that the program and the related data of the present invention are stored in the hard disk. It is possible to execute.

In this case, when the program of the present invention is executed in the laser beam printer according to the first or second embodiment of the present invention, for example, through a device such as a computer as shown in FIG. The program can be executed by supplying the program and related data of the present invention to the laser beam printer or by storing the program and related data of the present invention in the laser beam printer in advance.

FIG. 5 is an explanatory diagram showing a configuration example of the storage contents of a storage medium storing the program and related data of the present invention. The storage medium of the present invention stores, for example, volume information 5
1, directory information 52, program execution file 5
3. The storage contents of the program-related data file 54 and the like. The program of the present invention is program-coded based on the operation procedure described later in the first embodiment and the second embodiment.

It should be noted that each constituent element in the claims of the present invention, the first embodiment of the present invention, and the second
Correspondence with each part in the embodiment is as follows. The image processing means corresponds to the video controller 103, the position detecting means corresponds to the photodiode 24 and the waveform shaping circuit 20, and the transporting means corresponds to a transport mechanism including the paper feed roller 121 and other rollers. The starting means, the control means, the receiving means, and the changing means correspond to the engine controller 105, and the leading end detecting means and the trailing end detecting means are T
The light reflecting means corresponds to the polygon mirror 108, the driving means corresponds to the scanner motor 21, the light collecting means corresponds to the fθ lens 23, the light emitting means corresponds to the semiconductor laser 107, The modulating unit corresponds to the laser driver 106, the photosensitive unit corresponds to the photosensitive drum 112, the charging unit corresponds to the primary charger 111, the developing unit corresponds to the developing unit 113, and the transfer unit corresponds to the transfer charger 114.
Corresponding to

Next, the first embodiment of the present invention configured as described above is described.
The output control operation of the horizontal synchronizing signal (BD signal) in the laser beam printer according to the embodiment will be described in detail with reference to FIGS. FIG. 3 is a timing chart showing the state of each signal in the laser beam printer according to the first embodiment of the present invention.

When a printing operation is instructed by the video controller 103 of the controller unit 100, the engine controller 105 of the engine unit 102 activates the scanner motor 21 and forcibly drives the semiconductor laser 107. The laser light emitted from the semiconductor laser 107 is shaped by the coupling lens 22, and then reflected by the polygon mirror 108 rotated by the scanner motor 21 and fθ
The light passes through the lens 23 and periodically strikes the photodiode 24. The signal from the photodiode 24 is amplified by the amplifier 25, shaped into a pulse waveform 30 by the waveform shaping circuit 20, and input to the engine controller 105.

If the engine controller 105 determines that the pulse cycle is normal, it assumes that the scanner motor 21 has stabilized at the number of revolutions necessary for the printing operation, starts the above-described printing operation, and forcibly drives the semiconductor laser 107. Is stopped, and the video signal 31 input from the video controller 103 drives the semiconductor laser 107. The laser light emitted from the semiconductor laser 107 passes through the optical path described above, is reflected by the polygon mirror 108, and f
The light scans the photosensitive drum 112 through the θ lens 23.

In such a case, since the video signal 31 generates dot information in synchronization with the horizontal deflection scanning of the laser light, a horizontal synchronization signal for indicating that the laser light has reached a predetermined position is necessary. It is. In addition, a vertical synchronizing signal for aligning the writing position in the transport direction on the sheet is also required. The engine controller 105 transmits synchronization information to the video controller 103 as follows. The horizontal synchronization signal is called a BD signal and is output as follows.

When the pulse waveform 30 is input from the waveform shaping circuit 20 to the engine controller 105, the BD signal generation circuit 32 synchronizes the BD signal 34 having the pulse width t 1 with the video controller 103 in synchronization with the fall of the pulse waveform 30.
Output to Here, the BD signal generation circuit 32 is a CPU 3
3 can output a BD signal 34 having an arbitrary pulse width designated. When the conveyed sheet is on the TOP sensor, the TOP sensor 119 outputs a / TOP signal 35.
Is set to “L” and output. The CPU 33 outputs the / TOP signal 3
5, the leading edge of the sheet is detected, and the BD signal generation circuit 32 supplies the BD signal 34 having a pulse width t2 wider than usual.
Is sent. Upon receiving an instruction to change the pulse width of the BD signal 34 from the CPU 33, the BD signal generation circuit 32 changes the pulse width of the next one pulse to t2 and outputs it.

The video controller 103 uses the BD signal 34 having a wide pulse width as a vertical synchronizing signal,
One line of pixel data is transmitted as a video signal to the laser driver 106 in synchronization with the D signal 34, and an image is formed as described above. When the image formation proceeds and the sheet passes through the TOP sensor 119, the / TOP signal 35 becomes "H". The CPU 33 of the engine controller 105 is / T
When the trailing edge of the sheet is detected at the rising edge of the OP signal 35,
As in the case of the leading edge of the sheet, an instruction is sent to the BD signal generation circuit 32 to output a BD signal 34 having a pulse width wider than usual.

When the BD signal generating circuit 32 of the engine controller 105 receives an instruction from the CPU 33 to widen the pulse width of the BD signal 34, the pulse width of the next one pulse is changed and output. When the video controller 103 receives the BD signal 34 having a wide pulse width again, the video signal 103 is used as a synchronization signal for ending in the vertical direction, and stops transmitting pixel data to the laser driver 106 as a video signal. Wait for image formation.

In the first embodiment of the present invention, the pulse width of the BD signal at the leading edge of the sheet and the pulse width of the BD signal at the trailing edge of the sheet are the same t2, but different pulse widths are used. Is also good.

As described above, according to the laser beam printer of the first embodiment of the present invention, the video controller 103 for performing image processing and the image forming operation based on the image data sent from the video controller 103 Controller, a photodiode 24 for detecting a scanning reference position of a light beam scanned from an optical system such as a semiconductor laser 107, a polygon mirror 108, and an fθ lens 23, and a pulse waveform of an amplified signal of the photodiode 24. A waveform shaping circuit 20 for shaping
The engine controller 105 includes a transport mechanism that transports the paper to the transfer position and a TOP sensor 119 that detects the leading end of the paper in the transport direction. The engine controller 105 synchronizes with a pulse waveform (beam position pulse signal) output from the waveform shaping circuit 20. To transmit the horizontal synchronization signal of the image data to the video controller 103 with the first pulse width, the conveyance start control to start the conveyance of the sheet by the conveyance mechanism based on the instruction of the video controller 103, and the top edge of the sheet by the TOP sensor 119. Since the horizontal synchronization signal is changed to the second pulse width based on the detection and output, the video controller 103 is controlled to transmit the vertical synchronization of the start of the image data, so that the following operations and effects are obtained.

In the above configuration, the engine controller 105 controls the laser driver 106 to control the laser beam emitted from the semiconductor laser 107 to be reflected by the rotating polygon mirror 108 and scan the photosensitive drum 112. The photodiode 24 detects a scanning reference position of the laser beam scanned by the polygon mirror 108 and outputs the same to the waveform shaping circuit 20 via the amplifier 25. The BD signal generation circuit 32 of the engine controller 105 outputs a horizontal synchronization signal (BD signal) to the video controller 103 in synchronization with the output pulse of the waveform shaping circuit 20.

CPU 33 of engine controller 105
Controls the laser beam intensity of the semiconductor laser 107 to be modulated via the laser driver 106 based on the image data from the video controller 103. The CPU 33 of the engine controller 105 is the video controller 10
3 is controlled to perform light modulation via the laser driver 106. The TOP sensor 119 detects the leading edge of a sheet of recording medium that has been conveyed.
Here, the CPU 33 of the engine controller 105
The pulse width of the horizontal synchronization signal is changed in response to the output signal of the OP sensor 119, and the vertical synchronization is transmitted to the video controller 103 via the BD signal generation circuit 32.

Therefore, in the first embodiment of the present invention, since the horizontal synchronizing signal and the vertical synchronizing signal can be transmitted by one signal line, the number of synchronizing signals required for the image forming operation can be reduced. In addition, there is an effect that the processing load of the video controller can be reduced.

[Second Embodiment] A laser beam printer according to a second embodiment of the present invention has a controller unit 100 and an engine unit 1 similar to the first embodiment.
02, and the controller unit 100
Are the host I / F circuit 101 and the video controller 10
3. An operation panel 104 is provided. The engine unit 102 includes an engine controller 105, a laser driver 106, a semiconductor laser 107, a polygon mirror 108, and a mirror 10.
9, primary charging device 111, photosensitive drum 112, developing device 11
3, a transfer charger 114, a cleaning device 115, a fixing device 116, a TOP sensor 119, a paper cassette 120, and a paper roller 121 (see FIG. 2).

The control system of the laser beam printer according to the second embodiment of the present invention is, like the first embodiment, an engine controller having a video controller 103, a BD signal generation circuit 32, and a CPU 33. 10
5, laser driver 106, semiconductor laser 107, polygon mirror 108, photosensitive drum 112, TOP sensor 1
19, a waveform shaping circuit 20, a scanner motor 21, a coupling lens 22, an fθ lens 23, a photodiode 24, and an amplifier 25 (see FIG. 1 described above). The configuration and the basic operation of the laser beam printer according to the second embodiment are the same as those of the first embodiment, and a description thereof will be omitted.

Next, the second embodiment of the present invention configured as described above
The output control operation of the horizontal synchronizing signal (BD signal) in the laser beam printer according to the embodiment will be described in detail with reference to FIG. FIG. 4 is a timing chart showing the state of each signal in the laser beam printer according to the second embodiment of the present invention.

In the second embodiment of the present invention, a synchronization signal is generated as follows. When the CPU 33 of the engine controller 105 detects the leading edge of the sheet by the / TOP signal 35, it instructs the BD signal generation circuit 32 to start outputting the BD signal 34. The BD signal generating circuit 32 is in a non-output state until receiving an instruction from the CPU 33. When receiving an instruction from the CPU 33, the BD signal generating circuit 32 outputs one pulse of the BD signal 34 having a pulse width t2 and then synchronizes with the falling edge of the pulse waveform 30. The BD signal 34 having the pulse width t1 is supplied to the video controller 103.
Output to The video controller 103 transmits the video signal 31 to the laser driver 106 by synchronizing the signal of the first pulse width t2 as a vertical synchronization signal and the signal of the pulse width t2 as a horizontal synchronization signal.

When the image formation proceeds and the sheet passes through the TOP sensor 119, the / TOP signal 35 becomes "H". The CPU 33 of the engine controller 105 is / T
When the trailing edge of the sheet is detected at the rising edge of the OP signal 35,
The BD signal generation circuit 32 is notified that the trailing edge of the sheet has been detected. Upon receiving the information about the trailing edge of the sheet, the BD signal generation circuit 32 stops outputting the BD signal 34. If the video controller 103 does not receive the BD signal 34 for a certain period of time or more, the video controller 103 determines that it is the rear end of the sheet, stops transmitting pixel data as the video signal 31 to the laser driver 106, and waits for image formation on the next sheet I do.

As described above, according to the laser beam printer of the second embodiment of the present invention, the video controller 103 for performing image processing and the image forming operation based on the image data sent from the video controller 103 Controller, a photodiode 24 for detecting a scanning reference position of a light beam scanned from an optical system such as a semiconductor laser 107, a polygon mirror 108, and an fθ lens 23, and a pulse waveform of an amplified signal of the photodiode 24. A waveform shaping circuit 20 for shaping
The engine controller 105 includes a transport mechanism that transports the paper to the transfer position and a TOP sensor 119 that detects the trailing end of the paper in the transport direction. The video controller 103 outputs a horizontal synchronizing signal having a second pulse width or a third pulse width based on the control for outputting information indicating the presence of the sheet and the detection of the trailing edge of the sheet by the TOP sensor 119.
The following operations and effects are achieved because the control for transmitting the vertical synchronization of the end of the image data to the image data is performed.

In the above configuration, when the CPU 33 of the engine controller 105 detects the leading edge of the sheet via the TOP sensor 119, the BD signal generation circuit 32 outputs the pulse width t2.
After outputting one pulse of the BD signal 34, the BD signal 34 having the pulse width t1 is output to the video controller 103 in synchronization with the fall of the pulse waveform 30. Video controller 1
Reference numeral 03 synchronizes the signal having the pulse width t2 as a vertical synchronization signal and the signal having the pulse width t2 as a horizontal synchronization signal, and transmits the video signal 31 to the laser driver 106. The CPU 33 of the engine controller 105 is TOP
When the trailing edge of the sheet is detected via the sensor 119, the BD signal generation circuit 32 stops outputting the BD signal. If the video controller 103 does not receive the BD signal 34 for a certain period of time or more, it determines that the sheet is at the trailing end, and stops transmitting the video signal to the laser driver 106.

Therefore, in the second embodiment of the present invention, since the horizontal synchronizing signal and the vertical synchronizing signal can be transmitted through one signal line, the number of synchronizing signals required for the image forming operation can be reduced. In addition, there is an effect that the processing load of the video controller can be reduced.

[Other Embodiments] The first embodiment of the present invention described above.
In the second embodiment, the case where a printer is used as an image forming apparatus has been described as an example, but the present invention is not limited to a printer, and image information is read from a document by image reading means, and read data is read. The present invention can also be applied to a copying machine having a configuration in which image processing is performed by an image processing unit and image formation is performed by an image forming unit based on image processing data.

In the first and second embodiments of the present invention described above, the case of a single image forming apparatus has been described as an example. However, the present invention is not limited to a single image forming apparatus. For example, the present invention can be applied to a system in which the image forming apparatus of the present invention, an information processing apparatus such as a computer, and an image reading apparatus such as a scanner are connected via a network.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device. A storage medium storing software program codes for realizing the functions of the above-described embodiments is supplied to a system or an apparatus, and a computer (or CPU or MPU) of the system or the apparatus executes the program code stored in the storage medium. Needless to say, this can also be achieved by executing the reading.

In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention. As a storage medium for supplying the program code, for example, a floppy disk, a hard disk, an optical disk, a magneto-optical disk,
A CD-ROM, CD-R, magnetic tape, nonvolatile memory card, ROM, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS or the like running on the computer is actually executed based on the instructions of the program code. It goes without saying that a part or all of the above-described processing is performed, and the functions of the above-described embodiments are realized by the processing.

Further, after the program code read from the storage medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instruction of the program code, It goes without saying that the CPU provided in the function expansion board or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0064]

As described above, according to the image forming apparatus of the first to sixth aspects, the horizontal synchronizing signal is changed to the second pulse width and output based on the detection of the leading end of the recording medium in the transport direction. Control to transmit vertical synchronization of the start of image data to the image processing means, and output a horizontal synchronization signal of a second pulse width or a third pulse width based on detection of the rear end of the recording medium in the transport direction. Since the control for transmitting the vertical synchronization of the end of the image data to the image processing means is performed, the horizontal synchronization signal and the vertical synchronization signal can be transmitted through one signal line. This has the effect of reducing the number and reducing the processing load on the image processing means.

According to the signal control method of the present invention, by executing the signal control method of the present invention in the image forming apparatus, the number of synchronization signals required for the image forming operation can be reduced. And the processing load on the image processing means can be reduced.

According to the storage medium of the present invention, the signal control method is read from the storage medium of the present invention and executed by the image forming apparatus. This has the effect of reducing the number of synchronization signals and reducing the processing load on the image processing means.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a control system of a laser beam printer according to first and second embodiments of the present invention.

FIG. 2 is a configuration diagram illustrating a configuration example of a laser beam printer according to first and second embodiments of the present invention.

FIG. 3 is a timing chart showing a state of each signal in the laser beam printer according to the first embodiment of the present invention.

FIG. 4 is a timing chart showing a state of each signal in a laser beam printer according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a configuration example of storage contents of a storage medium storing a program and related data of the present invention.

FIG. 6 is an explanatory diagram showing a conceptual example in which a program and related data of the present invention are supplied from a storage medium to an apparatus.

[Explanation of symbols]

 Reference Signs List 20 waveform shaping circuit 24 photodiode 32 BD signal generation circuit 33 CPU 103 video controller 105 engine controller 119 TOP sensor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 1/23 103 H04N 1/12 Z (72) Inventor Tetsuo Kishida 3-30-2 Shimomaruko, Ota-ku, Tokyo No. F term in Canon Inc. (reference) 2C362 BB32 BB34 BB37 BB42 BB47 CB52 CB54 CB74 2H045 AA01 CA88 CA98 5C072 AA03 BA02 HA12 HB02 HB13 NA04 RA04 UA17 XA01 XA05 5C074 BB03 CC26 EE02 EE04 H

Claims (18)

[Claims] 1. An image forming apparatus for forming an image on a recording medium such as paper based on optical scanning by an optical system according to image data, comprising: an image processing unit for sending image data to the image forming system; Position detecting means for detecting a scanning reference position of the scanned light beam; and a first pulse for transmitting a horizontal synchronizing signal of the image data to the image processing means in synchronization with a beam position pulse signal outputted from the position detecting means. Transmitting means for transmitting the recording medium at a width, conveying means for conveying the recording medium to the image forming position, conveying start means for starting the conveying of the recording medium to the conveying means based on an instruction of the image processing means, A leading edge detecting means for detecting a leading edge in the transport direction, and changing the horizontal synchronizing signal to a second pulse width based on the leading edge detection by the leading edge detecting means and outputting the same. Image forming apparatus characterized by a control means for transmitting a vertical synchronization of the start of image data. 2. An optical scanning means comprising: a light reflecting means for reflecting light; a driving means for rotating the light reflecting means; a condensing means for condensing a light beam reflected by the light reflecting means; A light emitting means for emitting a light beam toward the light reflecting means of the light scanning means, a light modulating means connected to an input of the light emitting means for modulating the intensity of the light beam, and a light modulating means connected to the input of the light modulating means Receiving means for receiving the image data from the image processing means and transmitting an image signal to the light modulation means, changing means for changing a pulse length of the horizontal synchronization signal, photosensitive means having a photosensitive function, and the photosensitive means Charging means for charging the surface of the photosensitive means charged by the charging means with an output beam of the light scanning means to form a charged image formed on the surface of the photosensitive means into a visible image of a developer. Developing means to convert 2. The image forming apparatus according to claim 1, further comprising a transfer unit configured to transfer the visible image converted by the developing unit to a recording medium. 3. The image forming apparatus according to claim 1, wherein the transmission unit outputs information indicating that the horizontal synchronization signal is not output during a period in which the horizontal synchronization signal is not output. . 4. A rear end detecting unit for detecting a rear end of the recording medium in a conveying direction, wherein the control unit detects a second pulse width or a third pulse width based on a rear end detected by the rear end detecting unit. 2. The image forming apparatus according to claim 1, wherein the horizontal synchronization signal having a pulse width is output to notify the image processing means of the vertical synchronization of the end of the image data. 5. The printer according to claim 1, wherein the printer is configured to form an image on a recording medium such as paper based on optical scanning by the optical system in accordance with image data received from an external device. An image forming apparatus according to claim 1. 6. A copying machine according to claim 1, wherein said copying machine is capable of forming an image on a recording medium such as paper based on optical scanning by said optical system in accordance with image data read from a document. An image forming apparatus according to claim 1. 7. A signal control method applied to an image forming apparatus that forms an image on a recording medium such as paper based on optical scanning by an optical system in accordance with image data, wherein the image processing includes sending image data to the image forming system. A position detecting step of detecting a scanning reference position of a light beam scanned from the optical system; and a horizontal position conversion of the image data to the image processing step in synchronization with a beam position pulse signal output from the position detecting step. A transmitting step of transmitting a synchronization signal with a first pulse width, a transporting step of transporting the recording medium to an image forming position, and a transport start of starting the transporting of the recording medium in the transporting step based on an instruction of the image processing step A leading edge detecting step for detecting a leading edge of the recording medium in the transport direction; and outputting the horizontal synchronization signal by changing the horizontal synchronizing signal to a second pulse width based on the leading edge detection in the leading edge detecting step. Signal control method characterized by a control step of transmitting the vertical sync of the start of image data to said image processing step in Rukoto. 8. An optical scanning method comprising: a light reflecting step of reflecting light by a light reflecting means; a driving step of rotating the light reflecting means; and a light collecting step of collecting the light beam reflected in the light reflecting step. A light emitting step of emitting a light beam toward the light reflecting means, a light modulation step of modulating the intensity of the light beam, and receiving the image data from the image processing step and transmitting an image signal to the light modulation step. Receiving process,
A changing step of changing a pulse length of the horizontal synchronizing signal; a photosensitive step of performing exposure by a photosensitive unit; a charging step of charging the photosensitive unit; and a light emitting unit that charges the surface of the photosensitive unit charged in the charging step with the light. A developing step of converting the charged image formed on the surface of the photosensitive means into a visible image of a developer by scanning with the output beam of the scanning step, and transferring the visible image converted in the developing step to a recording medium 8. The signal control method according to claim 7, further comprising the steps of: 9. The signal control method according to claim 7, wherein, in the transmitting step, information indicating that the horizontal synchronization signal is not output is output during a period in which the horizontal synchronization signal is not output. . 10. A rear end detecting step of detecting a rear end of the recording medium in a conveying direction, wherein the control step includes a step of detecting a second pulse width or a third pulse width based on a rear end detected by the rear end detecting step. 8. The signal control method according to claim 7, wherein the horizontal synchronization signal having a pulse width is output to notify the image processing step of the vertical synchronization of the end of the image data. 11. The printer according to claim 7, wherein the printer is capable of forming an image on a recording medium such as paper based on optical scanning by the optical system in accordance with image data received from an external device. 2. The signal control method according to 1. 12. A copying machine according to claim 7, wherein said copying machine is capable of forming an image on a recording medium such as paper based on optical scanning by said optical system in accordance with image data read from a document. 2. The signal control method according to 1. 13. A computer-readable storage medium storing a program for executing a signal control method applied to an image forming apparatus for forming an image on a recording medium such as paper based on optical scanning by an optical system according to image data. The signal control method includes: an image processing step of controlling image data to be sent to an image forming system; and a position detecting step of controlling to detect a scanning reference position of a light beam scanned from the optical system. Transmitting a horizontal synchronization signal of the image data with a first pulse width to the image processing step in synchronization with the beam position pulse signal output from the position detection step; A transport step for controlling transport to an image forming position, and a step before the transport step based on an instruction of the image processing step. A transport start step of controlling to start transport of the recording medium, a leading edge detecting step of controlling to detect a leading edge of the recording medium in the transport direction, and the horizontal synchronization signal based on the leading edge detection by the leading edge detecting step. A control step of performing control so as to transmit the vertical synchronization of the start of the image data to the image processing step by changing and outputting the pulse width to the second pulse width. 14. A light reflection step for controlling light to be reflected by the light reflection means, a driving step for controlling the light reflection means to rotate, and a light beam reflected in the light reflection step to be condensed. An optical scanning step consisting of a condensing step of controlling, a light emitting step of controlling to emit a light beam toward the light reflecting means, and an optical modulation step of controlling to perform intensity modulation of the light beam, A receiving step of receiving the image data from the image processing step and controlling the image signal to be transmitted to the light modulation step, a changing step of controlling to change a pulse length of the horizontal synchronization signal, and a photosensitive unit. A photosensitive step of controlling to perform photosensitive, and a charging step of controlling to charge the photosensitive means,
Developing the surface of the photosensitive unit charged in the charging step by scanning with the output beam of the optical scanning step to convert a charged image formed on the surface of the photosensitive unit into a visible image of a developer; 14. The storage medium according to claim 13, further comprising: a step of transferring the visible image converted in the developing step to a recording medium. 15. The transmission step, wherein, during a period in which the horizontal synchronization signal is not output, control is performed so as to output information indicating that the horizontal synchronization signal is not output. Storage media. 16. A method according to claim 16, further comprising the step of: detecting a rear end of the recording medium in a conveying direction, wherein the control step includes a second pulse width based on the rear end detected by the rear end detecting step. 14. The storage medium according to claim 13, wherein control is performed to output the horizontal synchronization signal having a third pulse width so as to transmit vertical synchronization of the end of image data to the image processing step. 17. The printer according to claim 13, wherein the printer is capable of forming an image on a recording medium such as paper based on optical scanning by the optical system in accordance with image data received from an external device. A storage medium according to claim 1. 18. The apparatus according to claim 13, wherein the apparatus is applicable to a copying machine that forms an image on a recording medium such as paper based on optical scanning by the optical system in accordance with image data read from a document. A storage medium according to claim 1.