JP2001235700A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of adjusting the width of a printing image accurately easily in a specified value range. SOLUTION: A fixing base driving means which makes a fixing base fixing an Fθ lens move forward and backward in a laser beam traveling direction is equipped.

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.

[0002]

2. Description of the Related Art An image carrier, a laser beam light source, a rotary polygon mirror for periodically scanning the image carrier with a laser beam generated from the laser beam light source, and a scanning speed on the image carrier are provided. An Fθ lens to make it constant,
In an image forming apparatus including a fixed base on which an Fθ lens is fixed, and a reflector for irradiating a laser beam emitted from the Fθ lens onto an image carrier, a printed image is generated due to variations in characteristics of the Fθ lens. May not be within the specified range.

[0003] In the conventional image forming apparatus,
The operator reads the width of the print image transferred to the recording medium, loosens the bolt 22 of the fixing table 18 to which the Fθ lens 16 is fixed as shown in FIG. Direction (arrow a direction or b direction)
(For example, if the width of the print image is smaller than the specified value, F
The width of the printed image is increased by moving the θ lens 16 in the direction b).

[0004]

However, in the case of the above structure, the operator loosens the bolts of the fixing stand to which the Fθ lens is fixed, and moves the fixing stand by hand to adjust the position of the Fθ lens. Therefore, a large amount of adjustment time is required, and it is difficult to adjust the position of the Fθ lens with high accuracy.

An object of the present invention is to provide an image forming apparatus capable of easily and accurately adjusting the width of a printed image within a specified value range.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an image carrier, a laser beam light source, and a rotary polygon mirror for periodically scanning the image carrier with a laser beam generated from the laser beam light source. An Fθ lens for keeping the scanning speed on the image carrier constant, a fixed base on which the Fθ lens is fixed, and irradiating a laser beam emitted from the Fθ lens onto the image carrier. And a reflector for moving the fixed base in the laser beam advancing direction.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes an image carrier for forming a toner image by an electrophotographic process, which is supported by a spindle so as to rotate at a constant speed in the direction of arrow a. The charger 2 is arranged so as to face the surface of the image carrier 1, and uniformly charges the surface of the image carrier 1 passing therethrough so as to face the charger 2. The laser beam 3 for exposing the uniformly charged surface of the image carrier 1 is modulated according to a print information signal supplied from an information processing device to form an electrostatic latent image on the surface of the image carrier 1.

[0008] The developing device 4 is disposed so as to face the surface of the image carrier 1 on which the electrostatic latent image is formed. The developing device 4 has a developing function of forming a toner image by causing fine powder toner to adhere to the surface of the image carrier 1 with the electrostatic force of the electrostatic latent image.

The paper hopper 7 stores a continuous belt-like recording material (paper) 6 for transferring and fixing a toner image and performing image printing in a folded state. Conveyance rollers 8a and 8b constituting a part of the paper conveyance means take in the paper 6 from the hopper 7 and send it out to the image carrier 1. The paper 6 sent out from the transport rollers 8a and 8b comes into contact with the surface of the image carrier 1 so as to transfer a toner image to the surface. The transfer device 5 is provided with a sheet 6 in contact with the surface of the image carrier 1.
Generates an electrostatic force for moving (transferring) the toner image to the surface of the sheet 6 on the back surface of the sheet 6.

Conveyance rollers 9a and 9b, which constitute another part of the paper conveyance means, feed the paper 6 on which the toner image has been transferred to the preheater 10. The preheater 10 is provided at a position on the front side of the fixing roll pair 11 and contacts the back surface of the sheet 6 holding the toner image to preheat the sheet 6. The preheater 10 has a configuration in which, for example, an electric heating element is attached to the back surface of the heat transfer member with which the back surface of the paper 6 contacts. The paper 6 is heated to such an extent that the existing toner image is softened. The temperature of the preheater 10 is adjusted by controlling the current supplied to the electric heating element by the temperature control device 16.

A fixing roll pair 11 includes a heating roll 11a and a pressure roll 11b pressed against the heating roll 11a.
Heats and presses the preheated paper 6 in contact with the preheater 10 to fix the toner image on the surface of the paper 6. The paper 6 sent out from the fixing roll pair 11 is a puller roller 1
After passing through 2a and 12b, it is folded and stored in the stacker 13 or discharged outside the machine as shown by a broken line.
It is sent to a second printing device or post-processing device (not shown) arranged at the subsequent stage. FIG. 2 shows a detailed configuration of the image forming apparatus of the present invention. In FIG. 2, a laser beam 3 emitted from a laser beam light source 14 is reflected by a rotary polygon mirror 15, scanned by an Fθ lens 16 at a constant scanning speed, reflected by a reflector 17, and reflected by an image carrier. Reach 1 In addition, a stepping motor 19 is provided on the fixed base 18 to which the Fθ lens 16 is fixed, in order to move the fixed base 18 in the laser beam traveling direction (the direction of the arrow a or b) in the figure. The stepping motor 19 moves the fixed base 18 on which the Fθ lens 16 is fixed in accordance with the step amount output after the control unit 20 processes arbitrary data input from the scanning panel 21 by the laser beam in the figure. Move in the direction of travel.

The operation of adjusting the print image width according to the present invention will be described below. Since the width of the print image printed on the paper 6 as described above does not always become a constant value due to variations in the characteristics of the Fθ lens 16, it is necessary to adjust the width to fall within a predetermined value range. Therefore, the operator reads the width of the print image actually printed on the paper 6 and inputs data corresponding to the shift width to the operation panel 21, and the control unit 20 is based on the input data. The step amount is output to the stepping motor 19, and the stepping motor 19 moves the fixed base 18 in the laser beam traveling direction according to the step amount. The moving amount of the fixed base 18 moving per one pulse of the stepping motor 19 is several tens μm.
By setting the unit, high-precision adjustment is possible.

According to the above-described method, the width of the print image can be easily and accurately adjusted within the specified value range.

FIG. 4 is a schematic view showing another embodiment of the image forming apparatus of the present invention. In a multi-color printing apparatus having such a plurality of image forming apparatuses and multiplexing images of a plurality of colors on the same recording medium, it is necessary to accurately overlap the toner images formed on each image carrier. If the width of the print image differs for each color, a color shift occurs. Therefore, the application of the present invention in the above device is more effective.

[0015]

As described above, according to the present invention, it is possible to provide an image forming apparatus capable of simply and accurately adjusting the width of a printed image within a specified value range.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the overall configuration of an electrophotographic apparatus.

FIG. 2 is a perspective view of a main part showing the image forming apparatus of the present invention.

FIG. 3 is a perspective view of a main part showing a conventional image forming apparatus.

FIG. 4 is a schematic view showing another embodiment of the image forming apparatus of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image carrier, 2 ... Charger, 3 ... Laser beam, 4 ...
Developing device, 5: transfer unit, 6: recording material, 7: paper hopper,
8a, 8b, 9a, 9b: transport roller, 10: preheater, 11: fixing roll pair, 11a: heating roll, 11b
... Pressure rolls, 12a, 12b ... Pull rollers, 13 ...
Stacker, 14: laser beam light source, 15: rotating polygon mirror, 16: Fθ lens, 17: reflector, 18: fixed base,
19: stepping motor, 20: control unit, 21: operation panel, 22: bolt.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C362 AA48 BA86 BA90 DA02 2H045 AA01 BA02 CA63 DA02 5C072 AA03 BA02 BA04 DA02 DA04 DA23 XA01 XA05

Claims (1)

[Claims] An image carrier, a laser beam light source, and a rotating polygon mirror for periodically scanning the image carrier with a laser beam generated from the laser beam light source;
Fθ for keeping the scanning speed on the image carrier constant
A lens, a fixed base to which the Fθ lens is fixed,
A reflector for irradiating the laser beam emitted from the Fθ lens onto the image carrier; and a fixed table driving unit for moving the fixed table forward and backward in the laser beam traveling direction. An image forming apparatus comprising: