JP2001151382A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To print both sides of an undefined paper without causing printing positional displacement of an image in an image forming device. SOLUTION: This image forming device comprises a paper-size kind detecting means 20 for determining whether a defined paper is stored in a paper cassette, a paper-size inputting means 22 into which data on width of the undefined paper is inputted, a matching plate for positioning the conveyed paper in the width direction, of which one surface is fixed with a toner image, a matching plate control means 21 for moving the interval of the matching plate to a position matching to the paper size, based on information on the paper-size kind obtained by the paper-size kind detecting means 20 when the defined paper is stored in the paper cassette, and based on information on the paper size inputted to the paper-size inputting means 22 when the undefined sheet is stored in the paper cassette, and an automatic both-side print control means 19 for controlling a printing process to both sides of the paper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image output apparatus such as an office computer and a personal computer, and an image forming apparatus used for a copying machine.

[0002]

2. Description of the Related Art In recent years, image forming apparatuses, such as a color laser printer, capable of printing a color image on paper have been rapidly spread. With the spread of such documents, there are many cases where documents are printed on both sides of paper. Further, there is an increasing demand for printing on paper of various sizes.

Here, a conventional image printing apparatus will be described.

[0004] The image forming apparatus includes a photoreceptor as an image carrier. A laser scanning unit (hereinafter, referred to as “LSU”) for forming an electrostatic latent image on the photoconductor is provided near an outer peripheral surface of the photoconductor, and a black image, a cyan image, and a magenta image are developed by developing the electrostatic latent image. A developing device for forming an image and a yellow image is arranged.

Further, there is provided an intermediate transfer member which is brought into pressure contact with the photoreceptor and in which the respective color images formed on the photoreceptor are sequentially superimposed and transferred in color.

[0006] Below the photoreceptor, a paper cassette containing paper is arranged. The paper cassette is selectively provided with a plurality of ribs corresponding to the size of the stored paper, and a sensor for determining whether or not the paper cassette is a standard paper cassette is provided by the rib. I have.

A registration roller which feeds the sheet to the intermediate transfer member at a timing such that the leading end of the toner image formed on the intermediate transfer member coincides with the leading end of the sheet on a sheet transport path extending from the sheet cassette. A paper transfer roller for transferring the toner image formed on the intermediate transfer body to a paper,
A fixing device for fixing the toner image transferred to the sheet onto the sheet by heat and pressure, and a discharge conveyance roller for discharging the sheet after the toner image is fixed are sequentially provided.

A reversing device (reversing means) is provided adjacent to the conveyance path, for reversing the front and back sides of the sheet on which the toner image is fixed on one side and sending the reversal to the registration roller. A pair of alignment plates (guide means) are arranged on the traveling path of the sheet fed to the reversing device.

In the image forming apparatus having the above-described structure, first, black image data is sent to the LSU, and LS is applied to the photosensitive member uniformly negatively charged by the charger.
When U irradiates the laser, a latent image is formed on the photoconductor. When toner is supplied to the latent image, a black toner image is formed on the photoconductor. This toner image is transferred to an intermediate transfer member.

Next, the cyan image data is visualized,
The image is transferred in a color superimposed on the black toner image already held on the intermediate transfer member. Further, magenta and yellow are also transferred onto the intermediate transfer member in a similar process with these toner images being superimposed in color.

Next, a sheet is supplied at a timing by a registration roller, and the color toner image held on the intermediate transfer member is transferred onto one side of the sheet by a sheet transfer roller. The toner image transferred onto the paper is fixed on the paper in a fixing device. Then, the sheet on which the toner image has been fixed travels on the conveyance path by the discharge conveyance roller.

Next, the sheet discharge conveyance roller starts to rotate in the reverse direction, and the sheet is conveyed to the reversing device. Then, the sheet is positioned at an appropriate position by the alignment plate, and is sent to the registration roller again.

The sheet is conveyed by a registration roller in a timely manner so that the leading end of the toner image newly formed on the intermediate transfer member coincides with the leading end of the sheet. And
The toner image held on the intermediate transfer member is transferred onto the opposite surface of the sheet by the sheet transfer roller.

The sheet on which the toner image has been transferred on the opposite side is discharged onto a discharge tray through a transport path after the toner image is fixed by a fixing device.

FIG. 4 is a block diagram showing the configuration of a conventional image forming apparatus.

The conventional image forming apparatus includes an image data input means 17 for inputting image data, a paper size type detecting means 20 for judging whether a fixed size paper is stored in a paper cassette, an LSU, and a photoconductor. Forming and Printing Means 18 for Forming a Toner Image
And a matching plate control means (guide means control means) 21 for controlling the interval between the matching plates according to the sheet, and an automatic double-sided printing control means 19 for controlling a printing process on both sides of the sheet.

In such an image forming apparatus, a toner image is formed by the image forming and printing means 18 based on the image data input to the image data input means 17, and the image is printed on one side of a sheet.

The sheet on which the image is printed on one side is conveyed to automatic double-sided printing control means 19. Further, information on the paper size type (for example, information such as A4 paper or B5 paper) regarding the standard paper obtained by the paper size type detection means 20 is sent from the image forming and printing means 18 to the automatic double-sided printing control means 19.

In the automatic double-sided printing control means 19, the matching plate is moved to a position along the sheet width by using the matching plate control means 21 based on the sent information of the sheet type. Thus, the position of the sheet is adjusted by the alignment plate. The sheet whose position has been adjusted is conveyed again to the image forming and printing means 18 for printing on the opposite surface, where the image is printed on the opposite surface.

The sheet on which image printing has been performed on both sides in this manner is discharged to a discharge tray.

[0021]

However, in the conventional image forming apparatus as described above, since the size of the standard paper can be recognized and the alignment plate can move only to the position of the width of the standard paper, the irregular paper is used. In the case of (1), a gap is formed between the sheet and the alignment plate, so that the sheet becomes skewed or displaced.

If printing is performed in that state, there arises a problem that the paper is skewed or an image is not printed at an appropriate position on the paper.

In particular, when printing on irregular-size paper having a margin called "register mark" as used in the publication printing industry, or when printing on paper of any size desired by the user himself / herself, However, it is difficult to perform double-sided printing because the image is printed obliquely on the paper or printed out of the intended position.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of performing double-sided printing on irregular-size paper without causing a printing position shift of an image.

[0025]

In order to solve this problem, an image forming apparatus according to the present invention is provided with an image data input means for inputting image data, and whether or not fixed paper is stored in a paper cassette. Paper size type detecting means for determining, paper size input means for inputting data relating to the width of irregular-shaped paper, image forming and printing means for forming a toner image, and a toner image fixed on one side and conveyed A guide means for positioning the paper in the width direction and, when a fixed form paper is stored in the paper cassette, an irregular form of the paper cassette based on the information of the paper size type obtained by the paper size type detecting means. If paper is stored, the interval of the guide means is moved to a position suitable for the paper size based on the paper size information input to the paper size input means. A guide means control means is obtained by a structure having an automatic double-sided printing control means for controlling the printing process to both sides of the paper.

With this configuration, when the fixed size paper is stored in the paper cassette, the irregular size paper is stored in the paper cassette based on the size information of the fixed size paper detected by the paper size type detecting means. In such a case, the guide means moves to a position corresponding to the paper size based on the size information of the irregular-size paper input to the paper size input means, so that a gap is provided between the guide means and the paper. Does not occur. Therefore, the sheet is properly conveyed by the guide means, and it becomes possible to perform double-sided printing on irregular-size sheets without causing a printing position shift of an image.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, there is provided an image data input means for inputting image data, and a paper size type detection for judging whether or not fixed paper is stored in a paper cassette. Means, paper size input means for inputting data relating to the width of the irregular-shaped paper, image forming and printing means for forming a toner image, and positioning in the width direction of the paper on which the toner image is fixed and conveyed on one side. In the case where fixed paper is stored in the paper cassette, irregular paper is stored in the paper cassette based on the information of the paper size type obtained by the paper size type detection means. In this case, based on the paper size information input to the paper size input means, guide means control means for moving the interval of the guide means to a position suitable for the paper size, And an automatic double-sided printing control unit for controlling a printing process on both sides of the image forming apparatus.Since the sheet is properly conveyed by the guide unit, the irregular-shaped sheet is formed without causing a printing position shift of the image. Has the effect that double-sided printing can be performed.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In these drawings, the same members are denoted by the same reference numerals, and duplicate description is omitted.

FIG. 1 is a schematic diagram showing an entire configuration of an image forming apparatus according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing a main part of the image forming apparatus shown in FIG. 1, and FIG. It is a block diagram of a forming device.

As shown in FIG. 1, the image forming apparatus of the present embodiment includes a photosensitive member 2 which is an image carrier that rotates at a predetermined speed. In the vicinity of the outer peripheral surface of the photoreceptor 2, an LSU for forming an electrostatic latent image on the photoreceptor 2 by incorporating a polygon mirror which is rotated by a semiconductor laser element and a motor
1 and developing the electrostatic latent image into a black image, a cyan image,
A developing device 3 for forming a magenta image and a yellow image is arranged.

An intermediate transfer member 4 is provided which is brought into pressure contact with the photoreceptor 2, rotates at a predetermined speed, and sequentially transfers color images formed on the photoreceptor 2 in a superimposed manner.

Below the photosensitive member 2, a paper cassette 5 in which paper is stored is arranged. In the paper cassette 5,
A plurality of ribs 5a corresponding to the sizes of the stored sheets are selectively provided, and it is determined by the ribs 5a whether the sheet cassette 5 is a sheet cassette for fixed-size sheets, such as a row A or a row B. A sensor 13 is provided.

On the paper transport path 10 extending from the paper cassette 5 in the direction of arrow A, the leading edge of the toner image formed on the intermediate transfer member 4 and the leading edge of the paper taken out of the paper cassette 5 coincide. Roller 6, which feeds the paper to the intermediate transfer member 4 in a timely manner, the intermediate transfer member 4
A paper transfer roller 7 for transferring the toner image formed thereon to the paper, a fixing device 8 for fixing the toner image transferred to the paper to the paper by heat and pressure, and a paper discharge for discharging the paper after the toner image is fixed Transport rollers 9 are sequentially arranged.

A reversing device (reversing means) 11 is provided adjacent to the conveyance path 10 for reversing the front and back surfaces of the sheet on which the toner image is fixed on one side and sending the reversed sheet to the registration roller 6 again. . A pair of alignment plates (guide means) 12, which are driven by a motor 15 to position the paper in the width direction, are placed on the traveling path of the paper fed to the reversing device 11 by the paper discharge conveyance roller 9 rotated in the reverse direction.
16 are arranged.

In FIG. 2, the matching plates 12, 16 are
As shown in the direction of arrow B, they can approach and separate from each other, and are moved by the motor 15 to a position matching the width of the paper stored in the paper cassette 5 while maintaining the central position of the paper.

In the image forming apparatus configured as described above, dot data corresponding to each of the colors cyan, magenta, yellow, and black is sent to the LSU 1 for each main scanning line.

First, black image data is sent to the LSU 1, and the LSU 1 switches on and off the laser for each dot according to the black image data. Then, the LSU 1 irradiates such a laser to the photoconductor 2 uniformly negatively charged by a charger (not shown), and a latent image on the photoconductor 2 due to a potential difference generated by the laser irradiation. Is formed. The toner is attracted to the latent image formed on the photoconductor 2 by Coulomb force generated by a developing bias which is a predetermined voltage value applied to the developing device 3, and a black toner image is formed on the photoconductor 2. Is done. This toner image is transferred to the intermediate transfer member 4 after being subjected to light removal. Then, the toner image on the intermediate transfer member 4 is held on the intermediate transfer member 4 until the next image to be superimposed is transferred to the intermediate transfer member 4.

Next, the cyan image data is sent to the LSU 1 and, through the same process, is transferred to the intermediate transfer member 4 while being superimposed on the black toner image already held on the intermediate transfer member 4. . Further, magenta and yellow are also transferred onto the intermediate transfer member 4 in a similar process in such a manner that these toner images are superimposed in color.

On the other hand, the sheet is conveyed by the registration roller 6 at a proper timing. Then, the intermediate transfer member 4 is set so that the leading end of the toner image coincides with the leading end of the sheet.
The color toner image in which the four colors held thereon are superimposed on one another is transferred to one surface of the sheet by the sheet transfer roller 7. The toner image transferred onto the sheet is fixed on the sheet by heat and pressure in the fixing device 8. Then, the sheet on which the toner image has been fixed travels on the transport path 10 by the discharge roller 9.

Next, the paper discharge conveyance roller 9 starts to rotate in the reverse direction, and the paper is conveyed to the reversing device 11. Then, the paper is positioned at an appropriate position by the alignment plates 12 and 16, and
The sheet is sent to the registration roller 6 again.

The sheet is conveyed by the registration rollers 6 in a timely manner so that the leading edge of the toner image newly formed on the intermediate transfer member 4 and the leading edge of the sheet coincide. Then, the toner image held on the intermediate transfer body 4 is transferred onto the opposite surface of the sheet by the sheet transfer roller 7.

The sheet on which the toner image has been transferred on the opposite surface is fixed by the fixing unit 8 and then discharged onto the discharge tray 14 through the transport path 10.

Through the series of steps described above, double-sided printing of a color image is performed by the image forming apparatus.

Here, the configuration of such an image forming apparatus is shown in the block diagram of FIG.

As shown in the figure, the image forming apparatus according to the present embodiment has an image data input means 1 for inputting image data.
7, a paper size type detecting means 20 for determining whether or not fixed paper is stored in the paper cassette 5, a paper size input means 22 for inputting data relating to the width of irregular paper, an LSU 1 and a photoconductor. 2. Image forming and printing means 18 which is composed of the developing device 3 and forms a toner image
And a matching plate control means (guide means control means) 21 for controlling the interval between the matching plates according to the sheet, and an automatic double-sided printing control means 19 for controlling a printing process on both sides of the sheet.

In such an image forming apparatus, a toner image is formed by the image forming and printing means 18 based on the image data input to the image data input means 17, and the image is printed on one side of a sheet.

The paper on which the image is printed on one side is conveyed to automatic double-sided printing control means 19.

Here, when the paper size type detecting means 20 determines that the standard size paper is stored in the paper cassette 5, the information of the paper size type regarding the standard size sheet obtained by the paper size type detecting means 20 is obtained. (For example, A
Information such as 4 sheets or B5 sheet) is sent from the image forming and printing means 18 to the automatic double-sided printing control means 19. Then, in the automatic double-sided printing control means 19, the matching plates 12, 16 are moved to a position suitable for the sheet size by the matching plate control means 21 based on the sent information on the standard sheet size. The position of the sheet is adjusted by such movement of the alignment plates 12 and 16.

On the other hand, if the paper size type detecting means 20 determines that irregular paper is stored in the paper cassette 5 or the paper size input means 22
When the user wants to print using the information of paper size, the information of the paper size (for example, information such as 80 mm in width and 210 mm in height) relating to the irregular-size paper inputted to the paper size input means 22 is automatically printed from the image forming printing means 18. It is sent to the control means 19. Then, in the automatic double-sided printing control means 19, the matching plates 12, 16 are moved to a position suitable for the sheet size by the matching plate control means 21 based on the sent information on the irregular-sized sheet size. Such an alignment plate 1
The position of the irregular-shaped sheet is adjusted by the movement of the sheets 2 and 16.

The fixed-form or irregular-form paper whose position has been adjusted in this way is conveyed again to the image forming and printing means 18 for printing on the opposite surface, where the image is printed on the opposite surface.

The paper on which image printing has been performed on both sides is discharged to a discharge tray.

As described above, according to the present embodiment, when standard paper is stored in the paper cassette 5, the standard paper is detected based on the standard paper size information detected by the paper size type detecting means 20. When irregular paper is stored in the cassette 5, the matching plates 12, 1 are determined based on the irregular paper size information input to the paper size input means 22.
6 moves to a position corresponding to the sheet size, so that no gap is generated between the alignment plates 12 and 16 and the sheet. As a result, the paper is properly conveyed by the alignment plates 12 and 16, and it is possible to perform double-sided printing on irregular-shaped paper without causing a printing position shift of an image.

The paper in this specification is not limited to paper, but includes various recording media other than paper, such as OHP sheets.

[0054]

As described above, according to the present invention, when a standard paper is stored in a paper cassette, the paper cassette is set based on the size information of the standard paper detected by the paper size type detecting means. When irregular paper is stored in the paper, the guide moves to a position corresponding to the paper size based on the irregular paper size information input to the paper size input means, and the paper is moved by the guide. Since the paper is properly conveyed, it is possible to obtain an effective effect that double-sided printing of irregular-sized paper can be performed without causing a printing position shift of an image.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall configuration of an image forming apparatus according to an embodiment of the present invention;

FIG. 2 is a schematic diagram illustrating a main part of the image forming apparatus of FIG. 1;

FIG. 3 is a block diagram of the image forming apparatus of FIG. 1;

FIG. 4 is a block diagram illustrating a configuration of a conventional image forming apparatus.

[Explanation of symbols]

 12, 16 matching plate (guide means) 17 image data input means 18 image forming and printing means 19 automatic double-sided printing control means 20 paper size type detecting means 21 matching plate control means (guide means control means) 22 paper size input means

Claims (1)

[Claims] An image data input means for inputting image data, a paper size type detecting means for judging whether or not fixed paper is stored in a paper cassette, and data relating to the width of irregular paper are input. Paper size input means, an image forming and printing means on which a toner image is formed, a guide means for positioning the paper to be conveyed with the toner image fixed on one side thereof, and fixed paper in the paper cassette. If the paper cassette is stored, based on the information of the paper size type obtained by the paper size type detection means, if the irregular paper is stored in the paper cassette, it is inputted to the paper size input means. Guide means control means for moving the interval of the guide means to a position suitable for the paper size based on the information on the paper size, and printing on both sides of the paper. An image forming apparatus, comprising an automatic double-sided printing control means for controlling the process.