JPH05124748A - Sheet leading edge adjusting method for laser printer - Google Patents

Abstract

PURPOSE:To provide adjustability for the upper marginal zone formed at the leading edge of a sheet precisely and simply without use of any mechanical or electric circuitry adjusting mechanism by establishing a sheet leading edge adjusting method, by which the head position where the data stored in a memory is read is altered in compliance with the sheet leading edge adjusting value. CONSTITUTION:A printing memory zone 31 for the capacity admitting prints on a sheet and an adjusting memory zone 32 are set off in an image memory 13. The leading edge adjusting range 35 is identical to the range from the head address 33 of the image memory 13 till the coordinates origin address 34 which is the head address of the memory zone for printing 31. The image data sent from a host device is stored with the coordinates origin address 34 as the reference. The image data from the host device is stored in the image memory 13, and the sheet leading edge adjusting value is set by use of a keyboard etc. The read start address from the image memory 13 is determined in correspondence to the sheet leading edge adjusting value. This method does not require resorting to any mechanical or electric circuitry adjusting mechanism.

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 edge 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. 4 or 5 has been performed. FIG. 4 shows a method for adjusting the timing of sheet conveyance.
Is a method of adjusting the timing of laser beam emission.

In FIG. 4, a sheet is loaded from a sheet feed port 1. A paper top roller 3 is provided while the paper is being 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 when the solenoid is not 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 the paper under the drum 2. The sheet on which the toner image is transferred is further conveyed and discharged through the fixing device. The leading edge of the sheet is adjusted by determining the timing of operating the solenoid 4 according to the leading edge adjustment position.

The prior art shown in FIG. 5 is disclosed in, for example, Japanese Patent Publication No. 59-59.
It is disclosed in Japanese Patent No. 45981. FIG. 5A shows a state in which the feeding of the paper 7 is started on the drum 2 rotating in the direction 2R. In this state, no laser beam is generated from the laser beam generating means 5. Figure 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 with reference to the state of FIG. 5 (1). 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 with image information to form an electrostatic latent image on the drum 2 as shown in FIG. To 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 leading edge adjusting method as shown in FIG. 4, a mechanism for leading edge adjustment is required in the middle of the sheet conveying path. Since this mechanism performs a mechanical operation by the solenoid 4 or the like, there are large variations when the sheet is stopped or the sheet is again conveyed.

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

It is an object of the present invention to provide a method for adjusting the leading edge of a sheet of a laser printer, which does not require a mechanical or electric circuit adjusting mechanism and can be accurately and easily performed.

[0008]

According to the present invention, image data is stored in a memory, the stored image data is sequentially read from the head position, the intensity of a laser beam is modulated, and an image is formed on an image carrier. However, in the method for adjusting the leading edge position of the paper for the image transferred and recorded on the paper that is conveyed in synchronization with the image carrier, the memory can be used for the image that can be recorded on the paper. And a storage area for adjustment necessary for continuous reading are provided, and the leading position for reading the stored contents from the memory is changed according to the paper leading edge adjustment value. This is the method for adjusting the leading edge of the paper.

[0009]

According to the present invention, the image data stored in the memory is sequentially read from the leading position, the intensity of the laser beam is modulated to form an image on the image carrier, and the image is transferred onto a sheet. Will be recorded. The memory is provided with a print storage area and an adjustment storage area required for an image recorded on a sheet so that they can be read even if they are continuous. The leading position where the stored contents are read from the memory is changed according to the paper leading edge adjustment value. The time from the start of laser beam emission to the start of image data read-out by adjusting the interval on the memory from the start position where the stored contents are read out to the print storage area where the image data is stored. Can be adjusted, and the position of the leading edge of the paper can be adjusted corresponding to this time.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 receives image data sent from a host device through an input line 11 and an image memory 13 through an image generation data line 12. Store at. Host devices include computer networks, workstations, personal computers, and the like. 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 clock signal from the clock generation circuit 17 is applied to the output buffer circuit 15 via the clock line 16. The output buffer circuit 15 reads 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.

A laser beam emitted from the laser diode 19 is fan-shaped scanned by a polygon mirror or the like, and a light spot is axially scanned on the drum 20 which is an image carrier. A PIN diode 21 is provided at a position where the laser beam scanning the drum 20 deviates from one end of the drum 20. When the PIN diode 21 receives the laser beam, the C line passes through the start line 22.
A start timing signal for one line is given to PU10. The CPU 10 can know the start of scanning by the laser beam from the start timing signal of the first line.

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

FIG. 2 shows the state of the storage area in the image memory 13. The image memory 13 is provided with a print storage area 31 and an adjustment storage area 32 each having a printable capacity on paper. From the top 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 tip adjustment range 35. Figure 1
The image data sent from the host device in (1) is
It is stored based on the coordinate origin address 34. The width 36 of the print storage area 31 corresponds to the length of the scanning line that forms the image data on the paper. The storage area read from the image memory 13 is added to the width 36 of the printing storage area 31 in correspondence with the time when the laser beam moves beyond the width of the paper in the scanning line direction.
Becomes the width of. That is, the print storage area 31 is formed from the coordinate origin address 34 in the horizontal width 37 by the horizontal width 36.

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 the start point of the image data sent from the host device, and is defined as X = 0, 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 ## Address = B + (50 × n) +100 Here, 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 × n) This leading edge adjustment value C is a Y coordinate value from the leading edge of the sheet to the coordinate origin of the image recorded on the sheet, and corresponds to a so-called leading margin.

As described above, according to the present embodiment, as shown in FIG. 5, the timing of starting the first scan is not adjusted to read the stored contents of the same address from the memory, but from the time when the scan is started. The tip adjustment can be performed by starting reading from the memory and changing the start address.

[0020]

As described above, according to the present invention, the adjustment storage area which can be continuously read is provided in the printing storage area necessary for storing the image data in the memory. By starting reading from the memory from the head position in the adjustment storage area determined corresponding to the paper leading edge adjustment value, the head adjustment of the image recorded on the paper can be performed.
Therefore, a mechanical adjustment mechanism or an electric circuit for tip adjustment is not required, and the storage capacity of the memory may be increased.
Increasing the capacity of the memory realized by a semiconductor integrated circuit or the like can be easily realized as compared with a method of providing an adjusting mechanism or an adjusting circuit. Further, by recording the adjustment storage area so that the intensity of the laser beam rises sufficiently until the reading reaches the printing storage area from the beginning position, a stable image can be recorded on the paper. You can

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of an embodiment of the present invention and a flow chart 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 stored contents of image data in an image memory 13 shown in FIG.

FIG. 4 is a sectional view showing a conventional method for adjusting the leading edge of a sheet by a mechanical mechanism.

FIG. 5 is a schematic cross-sectional view showing a conventional electric paper edge 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 Printing Storage Area 32 Adjustment Storage Area 33 Start Address 34 Coordinate Origin Address 35 Tip Adjustment Range 38 Start Position

Claims (1)

[Claims] 1. Image data is stored in a memory, the stored image data is sequentially read from a leading position, the intensity of a laser beam is modulated, an image is formed on an image carrier, and the image carrier is synchronized with the image carrier. In a method for adjusting the position of the leading edge of a sheet with respect to an image transferred and recorded on a sheet that is conveyed as a sheet, a memory area for printing necessary for an image that can be recorded on the sheet is provided in a memory. A method for adjusting the leading edge of a sheet of a laser printer, wherein the adjustment storage area is continuously readable and the leading position for reading the stored contents from the memory is changed according to the leading edge adjustment value.