JP2000351503A - Initial position correction method for printing device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] Initial paper of a printing apparatus capable of accurately transporting paper even when using paper without a perforation hole and realizing high-quality printing without print position deviation. A position correction method is provided. Prior to the start of printing, load control means (22, 22) is switched while switching between feed conveyance of paper performed by rotating a drive roller (16) in a forward direction and return conveyance of paper performed by rotating a drive roller in a reverse direction. 23, 24, 25, 26, 27), the pressure contact load between the two rollers is adjusted, and the position of the end in the sheet width direction with respect to the detecting means (20) is aligned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method for correcting a paper initial position of a printing apparatus.

[0002]

2. Description of the Related Art FIG. Reference numeral 1 denotes a laser beam printer, and the photosensitive drum 3 starts rotating in the direction of the arrow based on a printing operation start signal from the controller 2. The photosensitive drum 3 rotates at a speed corresponding to the printing speed of the laser beam printer 1, and continues to rotate until the printing operation ends. When the photosensitive drum 3 starts rotating, a high voltage is applied to the corona charger 4, and the surface of the photosensitive drum 3 is uniformly charged with, for example, a positive charge. The rotating polygon mirror 5 starts rotating as soon as the power is turned on to the laser beam printer 1, and the constant speed rotation is maintained with high accuracy while the power is turned on. A laser beam output from a light source 6 such as a semiconductor laser or a light-emitting diode is reflected by a rotating polygon mirror 5 and irradiated while scanning the photosensitive drum 3 through an fθ lens 7.

When character data and graphic data converted into a dot image are sent from the controller 2 to the laser beam printer 1 as laser beam on / off signals,
A portion irradiated with the laser beam and a portion not irradiated are formed on the surface of the photosensitive drum 3, and a so-called electrostatic latent image is formed. When the photosensitive drum area holding the electrostatic latent image reaches a position facing the developing device 8, toner is supplied to the electrostatic latent image, and the photosensitive drum 3 is irradiated with a laser beam.
In the portion where the electric charge has disappeared, for example, a positively charged toner is attracted by static electricity, and a toner image is formed on the photosensitive drum 3.

[0004] The continuous paper 1 stored in the paper hopper 9
0 is transferred between the photosensitive drum 3 and the transfer device 12 by the paper transfer tractors 11 and 13 in synchronization with the timing at which the toner image of the print data formed on the photosensitive drum 3 reaches the transfer position. You. The toner image formed on the photosensitive drum 3 is transferred to the paper 10 by the action of a transfer unit 12 that applies a charge of the opposite polarity to the toner image on the back side of the paper 10.
Sucked up. In this way, the sheet 10 set on the sheet hopper 9 is conveyed to the fixing device 15 via the sheet conveying tractor 11, the transfer unit 12, the sheet conveying tractor 13 and the buffer plate 14.

The above description relates to a tractor transport mechanism using continuous paper in which feed holes are provided in advance at both edges in the width direction of the paper. This is a method of transporting by engaging with 13 pins. In the case of this type of tractor-conveying printing apparatus, a tractor provided at one end in the paper width direction is provided so as to be movable in the paper width direction, and a tractor provided at the other end in the paper width direction is fixed at a fixed position. The movable tractor is moved toward or away from the fixed tractor so that it can handle paper of various widths.

[0006]

When using continuous paper having no perforations, a roller is generally used instead of the paper transport tractor. In the case of the roller conveyance method, the position of the sheet with respect to the photosensitive drum is determined by conveying the sheet while abutting the end in the sheet width direction against the sheet guide plate. However, when the paper positioning by the paper guide plate is adopted, "flexure" or "bending" is likely to occur when thin paper with low rigidity is conveyed, and it cannot be loaded successfully along the paper guide plate. In addition, since the position of the sheet is shifted with respect to the photosensitive drum, the toner image is not transferred to an intended position, and a printing position shift occurs.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a printing apparatus capable of accurately conveying paper even when using paper without a perforation hole and realizing high-quality printing without a printing position shift. An object of the present invention is to provide a paper initial position correcting method.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a driving roller provided for switching between forward and reverse rotation, a pressing roller provided in pressure contact with the driving roller, and a pressing roller for the driving roller. Load control means for controlling the pressure contact load in the axial direction, and detection means for detecting the position of the end of the paper conveyed by the drive roller and the pressure roller in the width direction of the paper, before the start of printing, The load control unit adjusts the pressure contact load between the two rollers while switching between feed conveyance of the sheet performed by rotating the drive roller in the normal direction and return conveyance of the sheet performed by rotating the drive roller in the reverse direction. This is achieved by aligning the position of the paper width end with respect to the means.

[0009]

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

FIG. 4 shows the overall configuration of a laser beam printer. The same members as those in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted. 4 is different from FIG. 3 in that roller transport is used instead of tractor transport. In FIG. 4, the continuous paper 10 stored in the paper hopper 9 is formed on the photosensitive drum 3 by a transport roller 18 including a driving roller (hereinafter, referred to as a “rotating roller”) 16 and a pressing roller 17. In synchronization with the timing at which the toner image of the print data reaches the transfer position, the print data is conveyed between the photosensitive drum 3 and the transfer device 12.

The toner image formed on the photosensitive drum 3 is
The paper 10 is sucked onto the paper 10 by the action of the transfer unit 12 that applies a charge having a polarity opposite to that of the toner image to the back side of the paper 10. In this way, the paper 1 set in the paper hopper 9
0 is conveyed to the fixing device 15 via the conveying roller 18, the transfer device 12 and the buffer plate 14. A paper edge detection sensor 20 provided between the transport roller 18 and the transfer device 12 detects the position of the edge in the paper width direction, and applies the paper width direction between the transport rollers 18 according to the meandering amount obtained from the information. The meandering is corrected by changing the load.

Next, meandering correction will be described with reference to FIGS. The paper 10 is sandwiched between a pair of rollers consisting of a rotating roller 16 and a pressure roller 17, and the roller rotation drive unit 21 is capable of normal rotation and reverse driving. Carry out transportation. The paper edge detection sensor 20 is located on an extension in which the roller transport mechanism feeds and transports the paper by the forward rotation drive, and detects the position of the paper edge.

The roller end R side of the pressure roller 17 is one end of the right arm 22 and the roller end L side is a left arm 2.
3 is supported at one end, and each of the right arm 22 and the left arm 23 has a fulcrum 24 at an intermediate position. A wire 25 is tied to one end of the light arm 22,
The wire 25 is wound around the steering pulley 26 and then tied to one end of the left arm 23.

When the pressure roller driving unit 27, which is a stepping motor, is rotated clockwise (CW direction), a tension is applied to the wire 25 between the stepper pulley 26 and the light arm 22, and one end of the light arm 22 is directed downward. And the R side of the pressure roller 17 acts upward about the fulcrum 24. At the same time, a force acts downward on the L side of the pressure roller 17 due to the reverse action. When the pressure roller driving unit 27 is rotated in the counterclockwise direction (CCW direction), a force acts downward on the R side of the pressure roller 17 and acts upward on the L side by the same operation as described above.

By the operation described above, the pressure roller driving unit 27
When the roller is rotated in the CW direction, a load is applied on the R side of the pressure roller 17 as compared with the L side.
Is smaller on the R side than on the L side, the paper conveyance peripheral speed of the rollers is faster on the R side than on the L side, and the paper 10 is drawn closer to the R side. Conversely, when the pressure roller driving unit 27 is rotated in the CCW direction, the sheet 10 is pulled toward the L side by the same action. Based on the above operation, feedback control is performed so as to be at a predetermined position A based on the information on the sheet edge position detection sensor 20, and meandering correction of sheet conveyance is performed.

Based on the above description, the paper position initial correction control of the roller conveyance according to the present invention will be described with reference to the timing chart of FIG. 1 and the block diagram of FIG. The controller 2 sets a print signal, which is a print start command, to HIGH via the controller-engine interface 28. Upon receiving the print start command, the printer engine control unit 30 starts paper position correction prior to the printing operation.

The printer engine controller 30 reads "R5" of the sheet edge position sensor information. “R5” indicates that the vehicle is shifted 5 to the R side, and the position control unit 3 according to this information.
1 drives the pressure roller driving unit 26 by setting the pressure roller driving signal to HIGH in the CCW direction to five step positions so that the pressure roller driving unit angle becomes “CCW5”. When the pressure roller is driven in the CCW direction, a load is applied to the L side of the pressure roller. In this state, the speed control unit 29 sets the rotation roller inversion signal to LOW and sets the rotation roller drive signal to HIGH for the rotation roller driving unit 21 to perform feeding and conveyance.
The paper is pulled toward the L side by the load on the side, and approaches.

Subsequently, when the sheet edge position sensor information becomes "R3" during the feeding and transporting, the engine control unit 30 operates the pressure roller in the CW direction so that the pressure roller driving unit angle becomes "CCW3". The driving signal is set to HIGH to drive. The relationship between the angular positions is R3 <R5, and the load applied to the pressure roller L is reduced according to the sheet edge position sensor information. When the specified paper feed amount is reached, the rotation roller drive signal is set to LOW, and the feed conveyance is completed.

After the suspension period, the speed control unit 29 sets the rotating roller inversion signal to HIGH and sets the rotating roller drive signal to HIGH to the rotating roller driving unit 21 to carry out return conveyance. Since the pressure roller drive unit angle is "CCW3",
The paper is pulled further toward the L side by the return conveyance, and the paper is approached further. When the sheet edge position sensor information becomes “0”, the position control unit 31 drives the pressure roller drive signal to HIGH in the CW direction so that the pressure roller drive unit angle becomes “0”. The pressure roller drive unit angle becomes “0”, and the loads applied to the L and R sides of the pressure roller become uniform. When the specified paper feed amount is reached, the rotation roller drive signal is set to LOW, the return conveyance is completed, and the rotation roller inversion signal is set to LOW.

By the above-described series of operations, the sheet edge position sensor information reaches a predetermined position where the information is "0". After the pause period, the rotation roller drive signal is set to HIGH to start the printing operation.

[0021]

As described above, according to the paper initial position correcting method of the printing apparatus of the present invention, the paper can be accurately conveyed even when the paper having no perforation is used, and the printing position is not shifted. High quality printing can be realized.

[Brief description of the drawings]

FIG. 1 is a timing chart of the present invention.

FIG. 2 is a block diagram of the present invention.

FIG. 3 is an overall configuration diagram of a laser beam printer according to the related art.

FIG. 4 is an overall configuration diagram of a laser beam printer to which the present invention is applied.

FIG. 5 is a perspective view of a sheet conveying roller portion of the present invention.

FIG. 6 is an explanatory diagram showing a state of meandering correction.

[Explanation of symbols]

Reference numeral 16 denotes a rotating roller, 17 denotes a pressure roller, and 20 denotes a paper edge detection sensor.

Claims (1)

[Claims] A driving roller provided for switching between forward rotation and reverse rotation; a pressing roller provided in pressure contact with the driving roller; and a pressing load of the pressing roller against the driving roller in an axial direction. Load control means and detection means for detecting the position of the end of the sheet conveyed by the drive roller and the pressure roller in the sheet width direction are performed, and the drive roller is rotated forward before the start of printing. The load control means adjusts the pressure contact load between the two rollers while switching between the paper feed conveyance and the paper return conveyance performed by reversing the drive roller, and the position of the paper width direction end with respect to the detection means. A sheet initial position correction method for a printing apparatus, comprising: