JP2744370B2 - Paper printer tip adjustment method for laser printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting a blank area formed at the leading end of a sheet in a laser printer.

[0002]

2. Description of the Related Art Conventionally, a method for adjusting the leading edge of a sheet of a laser printer as shown in FIG. FIG. 4 shows a method for adjusting the timing of paper conveyance, and FIG.
Is a method for adjusting the timing of laser beam emission.

In FIG. 4, a sheet is fed from a paper feed port 1. A paper top roller 3 is provided while the paper is conveyed to the drum 2. The paper top roller 3 can be switched between a rotating state and a stopped state by a solenoid 4. The paper top roller 3 is in a stopped state unless the solenoid is activated, and is in a rotating state when the solenoid is activated. An electrostatic latent image is formed on the drum 2 by the laser beam 6 from the laser beam generator 5. When the drum 2 rotates, toner is supplied by the developing device 7, and a toner image is formed on the drum 2. The toner image is transferred to a sheet at a lower portion of the drum 2. The sheet on which the toner image has been transferred is further conveyed and discharged through a fixing device. The leading edge adjustment of the sheet is performed by determining the timing for operating the solenoid 4 according to the leading edge adjustment position.

[0004] The prior art shown in FIG.
No. 4,598,81. FIG. 5A shows a state where the feeding of the sheet 7 to the drum 2 rotating in the direction 2R is started. In this state, no laser beam is generated from the laser beam generating means 5. FIG. 5 (2)
5 shows a state in which the laser beam 8 from the laser beam generator 5 rises after a certain period of time has elapsed with reference to the state of FIG. When the generation of the laser beam 8 from the laser beam generator 5 reaches a steady state, the intensity of the laser beam is modulated by image information to form an electrostatic latent image on the drum 2 as shown in FIG. Do. This electrostatic latent image is developed in the same manner as in FIG. 4, and the toner image is transferred onto the sheet 7.
In order to adjust the leading edge of the sheet, it is necessary to adjust the timing of starting the laser beam emission as shown in FIG.

[0005]

In the conventional method for adjusting the leading edge as shown in FIG. 4, a mechanism for adjusting the leading edge is required in the middle of the paper transport path. Since this mechanism performs a mechanical operation using the solenoid 4 or the like, variations in stopping the sheet or starting the conveyance again are increased.

In the prior art shown in FIG. 5, the laser beam generator 5 needs an electric circuit or the like for stably starting the generation of the laser beam 8.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for adjusting the paper leading end of a laser printer, which does not require a mechanical or electric circuit adjusting mechanism and can be performed accurately and easily.

[0008]

According to the present invention, image data is stored in a memory, the stored image data is sequentially read from a head position, the intensity of a laser beam is modulated, and the intensity of a laser beam is modulated by laser beam scanning. An image for each line is formed on the paper, and the position of the leading edge of the paper is determined by the user of the laser printer with respect to the image of the laser printer transferred and recorded on the paper conveyed in synchronization with the image carrier. In the method for adjusting according to the setting, the timing at which the scanning position of the laser beam reaches a predetermined position can be detected, and the memory has an adjustment storage area and a printing area necessary for an image recordable on paper. The storage area is provided so that the data can be continuously read from the adjustment storage area to the print storage area, and the head position from which the stored contents are read from the memory in accordance with the paper leading edge adjustment value. When a change is made within the adjustment storage area and the laser beam scanning position is detected to have reached a predetermined position, the reading of the stored contents of the memory is started at consecutive addresses from the head position, and the stored contents of the printing storage area are read. This is a paper tip adjustment method for a laser printer, which is characterized by printing.

[0009]

According to the present invention, the image data stored in the memory is sequentially and continuously read from the head position, the intensity of the laser beam is modulated to form an image on the image carrier, and the image is formed on the paper. Is transferred and recorded. In the memory, a print storage area and an adjustment storage area required for an image recorded on a sheet are provided so as to be continuously readable from the adjustment storage area to the print storage area. The head position at which the stored contents are read from the memory is changed in accordance with the paper leading end adjustment value set by the user of the laser printer. By adjusting the interval on the memory from the head position where the stored contents are read from the memory to the printing storage area where the image data is stored, it is detected that the scanning position of the laser beam reaches the predetermined position. It is possible to adjust the time until the start of the reading of the image data, and it is possible to adjust the position of the leading edge of the sheet corresponding to this time.

[0010]

FIG. 1 shows the basic structure of the present invention in (1) and its operation in (2).

In FIG. 1A, a central processing unit (hereinafter abbreviated as “CPU”) 10 stores image data sent from a host device through an input line 11 into an image memory 13 through an image generation data line 12. Store in Examples of the host device include a computer network, a workstation, and a personal computer. The image data stored in the image memory 13 is sequentially read by the output buffer circuit 15 via the image read line 14. The output buffer circuit 15 is supplied with a clock signal from a clock generation circuit 17 via a clock line 16. The output buffer circuit 15 reads out the image data from the image memory 13 in synchronization with the clock signal, and drives the laser diode 19 via the output data line 18.

The laser beam emitted from the laser diode 19 is scanned in a fan shape by a polygon mirror or the like, and a light spot is scanned in an axial direction on a drum 20 as an image carrier. A PIN diode 21 is provided at a position where a laser beam that scans the drum 20 deviates from one end of the drum 20. When a laser beam is received by the PIN diode 21, C
The PU 10 is supplied with a one-line start timing signal. By the start timing signal of the first line, the CPU 10 can know the start of the scanning by the laser beam.

FIG. 1B shows the operation of the configuration shown in FIG. The operation is started from step a1.
In 2, the image data from the host device is stored in the image memory 13. In step a3, a paper leading edge adjustment value is set by a keyboard or the like (not shown). In step a4, the image memory 13
From which the read start address is determined. Step a5
Then, conveyance of the sheet is started, and in step a6, emission of the laser beam is started. The emission of the laser beam is performed, for example, by detecting that the sheet has been transported to a certain position. When the laser beam that scans the drum 20 reaches the PIN diode 21, reading of image data from the image memory 13 is started in step a7, and printing or recording on paper is started. When the reading of the image data is completed and the recording of the image data on the paper is completed, the operation is ended in step a8.

FIG. 2 shows the state of the storage area in the image memory 13. In the image memory 13, a print storage area 31 having a capacity capable of printing on paper and an adjustment storage area 32 are provided. From the head address 33 of the image memory 13,
The range up to the coordinate origin address 34 which is the start address of the print storage area 31 is the leading end adjustment range 35. FIG.
The image data sent from the host device in (1) is
It is stored based on the coordinate origin address 34. The horizontal width 36 of the print storage area 31 corresponds to the length of a scanning line that forms image data on paper. The storage area read out from the image memory 13 corresponding to the time when the laser beam moves beyond the width of the sheet in the scanning line direction is the printing storage area 3.
1 is added to the horizontal width 36, so that the horizontal width 37 becomes the horizontal width of the image memory 13. That is, the print storage area 31 is
From the coordinate origin address 34, a horizontal width 36 is formed within a horizontal width 37.

FIG. 3 shows the relationship between the creation of image data in the image memory 13 and its output. The coordinate origin address 34 is a start point of the image data sent from the host device, and is defined as X = 0 and Y = 0. Therefore, if the position of the character "B" is X = 100 and Y = 50, the address is represented by the equation (1).

[0016]

## EQU1 ## where B is the value of the coordinate origin address 34, and n is the value of the width 37 of the image memory 13.

Assuming that the leading edge adjustment value when reading the image data stored as described above is C, the address represented by the following equation (2) may be used as the read start position 38.

[0018]

## EQU2 ## Address = B- (C.times.n) The leading edge adjustment value C is a Y coordinate value from the leading edge of the sheet to the coordinate origin of an image printed on the sheet, and corresponds to a so-called leading margin.

As described above, according to this embodiment, as shown in FIG. 5, instead of adjusting the timing of the first scan start to read the stored contents at the same address from the memory, the first scan is started from the scan start time. The leading edge adjustment can be performed by starting the reading of the memory and changing the start address.

[0020]

As described above, according to the present invention, a printing storage area necessary for storing image data in a memory is provided with a continuously readable adjustment storage area. By starting reading from the memory from the head position in the adjustment storage area determined according to the paper leading edge adjustment value set by the user of the laser printer, the head adjustment of the image recorded on the paper is possible. It is. No mechanical adjustment mechanism or electrical circuit for tip adjustment is required, and the storage capacity of the memory may be increased. The increase in memory capacity realized by a semiconductor integrated circuit or the like can be easily realized as compared with a method of providing an adjustment mechanism or an adjustment circuit. In addition, a stable image can be recorded on paper by setting the adjustment storage area so that the intensity of the laser beam rises sufficiently and becomes stable before the read reaches the storage area for reading from the head position. Can be.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of an embodiment of the present invention and a flowchart showing its operation.

FIG. 2 is a diagram showing a storage area in an image memory 13 shown in FIG.

FIG. 3 is a diagram showing storage contents of image data in an image memory 13 shown in FIG. 1;

FIG. 4 is a cross-sectional view illustrating a conventional method of adjusting the leading edge of a sheet by a mechanical mechanism.

FIG. 5 is a schematic cross-sectional view showing a conventional electric paper tip adjusting method.

[Explanation of symbols]

 10 CPU 13 Image memory 15 Output buffer circuit 17 Clock generation circuit 19 Laser diode 20 Drum 21 PIN diode 31 Print storage area 32 Adjustment storage area 33 Start address 34 Coordinate origin address 35 Tip adjustment range 38 Start position

Claims (1)

(57) [Claims] An image data is stored in a memory, the stored image data is sequentially read from a head position, a laser beam intensity is modulated, and an image of one line is formed on an image carrier by laser beam scanning. A method for adjusting a paper leading end position according to a setting from a laser printer user with respect to an image of a laser printer formed and transferred on a paper conveyed in synchronization with an image carrier. The timing at which the scanning position of the laser beam becomes a predetermined position can be detected. The memory has an adjustment storage area and a print storage area necessary for an image recordable on paper, and an adjustment storage area. To the print storage area so that they can be read continuously, and the start position for reading the stored contents from the memory is changed in the adjustment storage area according to the paper leading edge adjustment value. When detecting that the scanning position of the laser beam has reached a predetermined position, reading of the stored content of the memory is started at a continuous address from the head position, and the stored content of the printing storage area is printed. Paper tip adjustment method for laser printer.