JPH0429870A - Laser recorder - Google Patents

Abstract

PURPOSE:To eliminate such a troublesome operation as a conventional change- over method by a jumper wire to facilitate a management of an engine board by providing an assignment means for assigning either a fixing means for fixing an image writing area in a main scanning direction in a fixed area or a change- over means for changing over the area in accordance with the size of transfer paper, and controlling the assignment means by an external device. CONSTITUTION:When a synchronous detection sensor of an optical writing unit 401 is turned ON, a DETP signal (detection pulse) is transmitted to an optical writing control circuit 103, whereby an engine board 101 informs a controller 104 of a main scanning start under timing control. After T1 CLKs, an LSYNC signal (synchronous signal) is turned ON and transmitted to the controller 104. The LSYNC signal (synchronous signal) is turned OFF after 8 CLKs, and after further 8 CLKs an LGATE signal is turned ON. After that, a WDATA signal (writing data) is transmitted from the controller 104 to the optical writing control circuit 103 correspondingly to the WCLK (clock signal). The optical writing control circuit 103 controls the optical writing unit 401, and an image is formed on a photosensitive drum.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser recording device that forms an image using a laser, such as a laser beam printer or a digital copying machine.

[Conventional technology]

In laser beam printers, etc., the image writing range in the main scanning direction is set by the LGATE signal.
Conventionally, there is a method in which the LGATE signal width is fixed to match the maximum transfer paper size, and a method in which the LGATE signal width is changed depending on the transfer paper size.

There are also laser beam printers that allow selection of the above two types of methods; in this case, one of the methods is set by switching jumper wires on the engine board.

[Problem to be solved by the invention]

However, with the method of fixing the LGATE signal width to the maximum transfer paper size, the engine board can be configured with a simple circuit, but if the transfer paper size is smaller than the maximum transfer paper size, writing will occur in areas other than the transfer paper width. Therefore, when the controller of the external device sends data, it has to send empty data to create a non-image area.

Further, in the method of changing the LGATE signal width according to the transfer paper size, it is not necessary to send empty data to create a non-image area as described above, but the configuration of the LGATE signal generation circuit on the engine board becomes complicated.

Furthermore, since controllers that process image data and generate video signals are no longer compatible with the above two methods, laser beam printers configured to allow selection of the above two methods are now available. However, in this case, the switching work using jumper wires is troublesome, and since there are two types of engine boards depending on the position of the jumper wires, there are problems in that unit management is troublesome and mistakes are likely to occur.

The present invention has been made in view of the above, and allows easy setting of the method required by the controller used, eliminates the trouble of switching methods using jumper wires as in the past, and allows the engine board to be easily set. The purpose is to facilitate management.

[Means for Solving the Problems] In order to achieve the above object, the present invention scans a laser beam to expose a photoreceptor to form an electrostatic latent image, and then develops the electrostatic latent image. In a laser recording device that performs transfer processing, fixing processing, and image formation, either a fixing means for fixing the image writing range in the main scanning direction to a certain range, or a switching means for switching according to the transfer paper size is used. The present invention provides a laser recording device that is provided with a specifying means for specifying, and the specifying means is controlled by an external device.

[For production]

According to the laser recording device of the present invention, by sending a command from the controller of the external device to the specifying means,
Select either a method in which the image writing range in the main scanning direction is fixed to a certain range or a method in which it is switched according to the transfer paper size.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail using the drawings.

FIG. 4 schematically shows the entire laser beam printer according to an embodiment of the present invention. An optical system unit 401 is disposed at the top of the laser beam printer, and an LD (laser diode) unit 410 is connected to the laser beam printer. The laser beam is configured to be emitted to an exposure position through an optical system including a lens and a reflecting mirror. A cylindrical photosensitive drum 403 is rotatably disposed below the optical system unit 401, and a developing unit 404 is disposed downstream of the exposure position to convert an electrostatic latent image formed by exposure into a visible image using toner. has been done. A transfer charger 405 is disposed adjacent to the developing unit 404 for transferring the toner image on the photoreceptor drum 303 to a transfer paper. A separation charger 411 is provided adjacent to the transfer charger 405 for peeling off the recorded transfer paper adsorbed onto the photosensitive drum 403 from the leading edge.
A conveyor belt 412 is disposed next to the conveyor belt 1, and a fixing device 407 for fixing the transferred image onto the transfer paper is disposed at the end of the conveyor belt 412. Further, a cleaning unit 408 is disposed above the conveyor belt 412 to remove toner remaining on the photoreceptor drum 403.

Further, a paper feed tray 406 for stacking transfer paper, and a transfer paper size detection sensor 409 for detecting the size of the transfer paper are installed at one end of the paper feed tray 406.

In the above configuration, the LD unit 410 emits a laser beam modulated according to pixel information, and the laser beam reaches the pre-charged photoreceptor drum 403 to sequentially form an electrostatic latent image. When the electrostatic latent image reaches a position facing the developing unit 404 due to the rotation of the photoreceptor drum 403, the electrostatic latent image is developed with toner, and the timing is adjusted so that the visible image resulting from this development reaches the transfer section. A transfer paper is fed from a paper feed tray 406, and a toner image is transferred onto the transfer paper by a transfer charger 405. The transfer paper after the transfer process is separated from the photosensitive drum 403 by a separation charger 411 and sent to a fixing device 407 by a conveyor belt 412. The fixing device 407 is
Heat and pressure are applied to the transfer paper to fix the toner image. The transfer paper after the fixing process by the fixing device 407 is
It is discharged directly outside the packaging.

FIG. 5 is a diagram showing the optical signal transmission path of the optical writing unit 401.

The LD unit 410 irradiates a laser beam to form an image on the photoreceptor drum 403 and to transmit a synchronization signal.The parallel light irradiated from the LD unit 4101 is rotated by a cylindrical lens 502. The laser beam is focused on the surface of a polygon mirror 503 inside.The laser beam is scanned in parallel by the rotation of the polygon mirror 503.

Further, the laser beam is reflected by the polygon mirror 503, passes through the Fθ lenses 504 and 505, and is reflected by the mirror 50.
6.507, passes through a shield plate (not shown) that protects the inside of the optical system from dust and dirt, and reaches the surface of the photosensitive drum 403.

A laser beam forms one main scanning line with a width of one dot from one surface of a polygon mirror 503 having a plurality of reflective surfaces. In addition to executing image writing, the laser beam is reflected by mirrors 506 and 507 and mirrors 508 and 509 as a synchronization signal for starting one line of main scanning, and turns on the synchronization detection sensor 510. When this synchronization detection sensor 510 turns on, the signal is transmitted to the engine board, which will be described later, and the engine board controls the timing and transmits the main scanning start to the controller of the external device.

FIG. 1 is a block diagram showing the configuration of a control section of the laser beam printer.

The engine board 101 is a CP that controls various processes.
It is composed of U102 and an optical writing control circuit 103 that controls the optical writing unit 401, and the CPU 10
2 sends and receives signals to and from the controller 104 of an external device through serial communication. The optical write control circuit 103 sends the WCLK signal (clock signal), LSYNC signal (synchronization signal), and LGATE Shingetsu (signal indicating the write range) to the controller 104, and conversely sends the controller 10
4 receives the WDATA signal (image data signal). Further, from the optical writing unit 401 to the optical writing control circuit 10
A DETP signal (detection pulse) is sent to the optical writing unit 401 from the optical writing control circuit 103.
A VIDEO signal (write data) is sent to.

Here, as shown in FIG. 2, the controller 1 of the external device
04, a command specifying the image writing range is sent to the CPU 102 of the engine board 101.

When the image writing range (LGATE signal width) is fixed,
The command “LG→FIX” to specify fixing is executed on CPU10.
2 by serial communication (201) L. After changing the image writing range based on the command, the CPU 10
2 to the controller 104 “”LG=F I
” (202).

Also, if the image writing range is variable depending on the transfer paper size, use the command "" LG → P S to specify the variable.
Z” to the CPU 102 (203), and after changing the image writing range based on the command, the CPU 102
returns "'LG=PSZ" to the controller 104 (204).

Writing on the photosensitive drum 403 with a laser beam is performed as shown in FIG. 3, and the writable range is as follows:
When the above command specifies that the LGATE signal width is fixed, the maximum width is set as indicated by A. Further, when the LGATE signal width is specified to be variable according to the transfer paper size, the writable range changes according to the transfer paper size as shown by A, B, and C.

Next, the control operation of the laser beam printer will be explained with reference to the timing chart shown in FIG.

When the synchronization detection sensor 510 of the optical writing unit 401 is turned on, a DETP signal (detection pulse) is sent to the optical writing control circuit 103. As a result, the engine board 10
1 controls the timing and transmits the main scanning start to the controller 104, CL KlaT l f&nir
, the SYNC signal (IJIJI signal) is turned on and sent to the controller 104.

The LSYNC signal (synchronization signal) turns off after BCLK, and the LGATE signal turns on after BCLK. Thereafter, the WDA is sent from the controller 104 to the optical write control circuit 103 in response to the WCLK signal (clock signal).
A TA signal (write data) is sent, and the optical write control circuit 103 controls the optical write unit 401 to form an image on the photoreceptor drum 403 .

The LGATE signal turns on the writable range bone, during which writing to the photosensitive drum 403 becomes possible.

For example, the command “LG
-Flχ′ is sent, the L GATE signal width (T
2) is equal to the maximum width A.

Also, when the command ° "LG→p s z" that changes the LGATE signal width according to the transfer paper size is sent, the above CLK number T several colors 1 GATE signal width T signal width thickness 2 according to the size By controlling, the writable range is changed.

〔Effect of the invention〕

As explained above, according to the laser recording device of the present invention,
Either a method that fixes the image writing range in the main scanning direction to a fixed range or a method that switches according to the transfer paper size can be specified by a command from an external device, so the method required by the controller used can be specified. Settings can be easily made, and since the engine board is common, there is no need to switch between both types using jumper wires as in the past, and engine board management becomes easy.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the control unit of a laser beam printer according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the status of command transmission from the controller to the engine board, and FIG. FIG. 4 is an explanatory diagram showing the overall configuration of the laser beam printer according to the present embodiment; FIG. 5 is an explanatory diagram showing the optical signal transmission path of the optical writing unit 401;
FIG. 6 is a timing chart showing the control operation according to this embodiment. Explanation of symbols 101-Engine board 102-CP Ul 03-
One optical writing control circuit 104 - Controller 401 - Optical writing unit 403 - One photosensitive drum 410 - LD unit 5
03-1-Polygon mirror 510...Synchronization detection sensor

Claims (1)

[Claims] After scanning a laser beam to expose a photoreceptor to form an electrostatic latent image, the electrostatic latent image is subjected to development processing, transfer processing, and fixing processing to form an image. A laser recording device is provided with a specifying means for specifying either a fixing means for fixing an image writing range in the main scanning direction to a certain range or a switching means for switching according to a transfer paper size, and the specifying means is controlled by an external device. A laser recording device characterized by controlling.