JP3402963B2 - Image forming device - Google Patents

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 in which a series of images are formed on an image carrier so as to be enlarged and transferred on a plurality of continuous transfer materials in a divided state. .

[0002]

2. Description of the Related Art Generally, a full-color image forming apparatus is provided with a digital color image reader section on the upper part and a digital color image printer section on the lower part.

With such a structure, various image processing can be performed. FIG. 6 shows an example in which continuous enlargement is doubled vertically and horizontally. When the copy key is pressed, the reader section divides the original document shown in FIG. 6A placed on the original table glass, and the original a1 portion is exposed and scanned by the exposure lamp, and the reflected light image is displayed in full color. The light is focused on the sensor and a color separated image signal of the original a1 portion is obtained. This color-separated image signal is processed by the video processing unit and sent to the printer section.

Further, in the exposure device of the printer section, the color separation image signal from the reader section is first converted into an optical signal for image scan exposure by the laser output section. Next, this optical signal passes through the laser exposure optical system and is projected on the charged surface of the photosensitive drum.

At the time of image formation in the printer section, the photosensitive drum is rotated in one direction to be neutralized by the pre-exposure lamp, and then uniformly charged negatively by the corona charger.
An optical signal is emitted for each separated color to form an electrostatic latent image.

Then, one of the developing devices corresponding to the optical signals for each separated color is operated to develop the electrostatic latent image on the photosensitive drum, and the photosensitive drum is negatively charged with resin as a substrate. To form a toner image.

Further, the transfer material (transfer paper) is conveyed from the transfer material cassette by a conveying system, and the toner image on the photosensitive drum is transferred at a position where the transfer device and the photosensitive drum face each other.

After the desired number of color images have been transferred in this way, the transfer paper is separated from the transfer drum and is discharged to the paper discharge tray via the heat roller fixing device, and the full color corresponding to the portion a1 of the original document. The image b1 portion is formed.

Similarly, the original a shown in FIG.
2, a3 and a4 portions are formed in the full color image b2, b3 and b4 portions shown in FIG.

Further, after the transfer of the toner image, the surface of the photosensitive drum is cleaned with a cleaning device to prepare for re-image formation.

[0011]

However, in the above-mentioned conventional image forming apparatus, for example, when the photosensitive drum is eccentric relative to the corona charger or the developing roller,
Depending on the degree of eccentricity, as shown in FIG. 6A, a full-color image (copy image) to be continuously magnified may have uneven charging due to a corona charger, a developing device As shown in FIG. 6 (b), for example, the density on the back side in the width direction of the transfer paper becomes darker and the density on the front side becomes darker on each copy image b1, b2, b3, b4 on the transfer paper due to uneven development due to A concentration gradient that becomes faint occurs. That is, density gradients of uneven charging and uneven developing occur in the longitudinal direction of the transfer paper. Therefore, when the enlarged and continuously copied copy images b1, b2, b3, b4 are pasted together,
As shown in FIG. 6C, there is a problem that the density difference at the joint may be noticeable.

The present invention has been made to solve the above problems, and when the image information is divided and formed on a plurality of transfer materials, the toner image at the joint of the transfer materials is an image carrier. It is an object of the present invention to provide an image forming apparatus in which an image is formed so that the density is the same so that the density difference at the joint is not noticeable.

[0013]

In order to achieve the above object, according to the image forming apparatus of the first aspect of the present invention, a rotatable image carrier and an image on the surface of the image carrier are provided. A toner image forming means for forming a toner image based on information, and a toner image in a state where one image information is divided into a plurality of pieces is transferred to different transfer materials, and a plurality of transfer materials are connected to form a series of images. And a toner image in a state in which the one image information is divided into a plurality of sheets in the paper width direction is used for one transfer material (for example, the first transfer material of FIG. 3B).
Material) and the other transfer material (for example, the third sheet of FIG.
(Transfer material) to form an image, and one transfer material after the toner image formation and the other transfer material are connected in the sheet width direction to form an enlarged toner image corresponding to the one image information. Toner formed on one of the transfer materials
-The direction of the toner image formed on the other transfer material
The shape is rotated 180 ° around the center of the other transfer material.
Characterized by comprising control means for controlling the toner image forming means so as to be formed by state.

According to a second aspect of the present invention, the toner image forming means is composed of a video processing unit.

According to a third aspect of the present invention, a transfer material is arranged outside the toner image forming area, which is a joint of the transfer materials, in order to form a series of enlarged toner images by bonding a plurality of transfer materials. Placed restriction mark to restrict.

According to a fourth aspect of the present invention, in order to form a series of enlarged toner images by connecting a plurality of transfer materials to each other outside the toner image forming area which is a joint of the transfer materials,
An alignment mark was provided to align the position of the transfer material.

According to a fifth aspect of the invention, in order to form a series of enlarged toner images by connecting a plurality of transfer materials to each other outside the toner image forming area which is a joint of the transfer materials,
An arrangement regulation mark for regulating the arrangement of the transfer material and an alignment mark for aligning the position are provided.

[0018]

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. <First Embodiment> FIG. 1 is a front view showing a schematic configuration of an image forming apparatus according to a first embodiment of the present invention.
6 is a flowchart illustrating an image forming method at the time of enlarged continuous shooting according to the first embodiment of the present invention.

In FIG. 1, the full-color image forming apparatus has a digital color image reader unit R on the upper side and a digital color image printer unit P on the lower side.

The reader section R has a document table glass 31 on which the document 30 is placed, and a document passage direction in the document sheet glass 31 (left-right direction) or a sheet-passage width direction and a sheet-passing direction (front-rear direction). Exposure lamp 32 that scans in a divided state in both directions (both directions in the present embodiment), a lens 33 that collects the reflected light image of the document 30 scanned by the exposure lamp 32, and the collected reflected light image A full color sensor 34 such as a CCD is provided.

Then, when a copy key (not shown) is pressed, the toner image forming means is controlled by the control means (not shown), and the full color sensor 34 passes through the above-described path, and the full-color sensor 34 corresponds to the enlargement copy ratio shown in FIG. ) As shown in FIG.
The reflected light images of the partial originals a1, a2, a3, a4 of a predetermined size, which are divided in both the width direction and the paper passing direction, are accumulated. Then, the full-color sensor 34 divides each of the partial originals a1, a2, a3, and a4 into a large number of pixels, generates a photoelectric conversion signal corresponding to the density of each pixel, and obtains a color-separated image signal. The color separation image signal is
The image is processed by a video processing unit (not shown) which constitutes toner image forming means via an amplifier (not shown), and is sent to the printer section P.

The printer section P is provided around the photosensitive drum 1.
A pre-exposure lamp 11, a corona charger 2 serving as a first charging unit, a surface potential sensor 12, and four developing units 4y and 4c for different colors of yellow, cyan, magenta, and black are provided along the rotation direction of the arrow R1. , 4m, 4bk, a light amount detecting means 13 for detecting the light amount on the photosensitive drum 1, a transfer means 5
With the configuration in which the cleaning device 6 is arranged, the photoconductive layer on the surface of the photosensitive drum 1 is formed of amorphous silicon, selenium, OPC, or the like.

The laser exposure optical system 3 includes a reader unit R
The image signal from is converted into an optical signal (laser light) E for image scan exposure by a laser output (not shown), the converted laser light E is reflected by the polygon mirror 3a, and is exposed through the lens 3b and the mirror 3c. Project on the surface of the drum 1.

The laser exposure optical system 3 is a partial original a1, a2, a3, a on which an image is formed on a drum type electrophotographic photosensitive member (hereinafter simply referred to as "photosensitive drum") 1 as an image bearing member.
4 of the partial originals a1 and a2 divided in the sheet passing width direction
First, an electrostatic latent image corresponding to is formed, and a portion of the partial originals a1, a2, a3, a4 divided in the sheet passing width direction based on the direction of the electrostatic latent images of the partial originals a1, a2. The electrostatic latent images corresponding to the originals a3 and a4 are formed in a direction in which the front side and the back side of the photosensitive drum 1 in the longitudinal direction are inverted by 180 °.

Further, a toner image forming means for forming a toner image based on image information is provided on the surface of the photosensitive drum 1, and a toner image obtained by dividing one image information into a plurality of pieces is transferred onto a transfer paper to form a series of images. Is formed by a plurality of transfer papers. Then, when these transfer papers after the toner image formation are connected in the paper width direction to form an enlarged toner image corresponding to one image information, the first direction of the reference direction is controlled by the control means.
The copy images corresponding to the partial originals a1 and a2 are formed on the second and second transfer papers, and the third and fourth transfer papers are inverted by 180 ° with respect to the transfer paper in the reference direction. The toner image forming means is controlled so as to form copy images corresponding to the originals a3 and a4.

In the printer section P, the photosensitive drum 1 is rotated in the direction of the arrow R1 in the drawing during image formation, and the photosensitive drum 1 is first discharged by the pre-exposure lamp 11 and then uniformly charged negatively by the corona charger 2. After that, laser light E is emitted for each separated color in accordance with the image information signal to form an electrostatic latent image. Next, the predetermined developing devices 4y, 4c, 4m,
4bk is operated to reverse-develop the electrostatic latent image on the photosensitive drum 1 with a two-component developer consisting of toner and carrier,
A negatively charged toner image (visible image) having a resin base is formed on the photosensitive drum 1.

Further, the transfer means 5 transfers the toner image on the photosensitive drum 1 to the transfer paper supplied from the transfer material cassette 7 by the conveying system at the transfer position facing the photosensitive drum 1. The transfer unit 5 includes a transfer drum 5a that is rotatably driven, a transfer brush charger 5b, an adsorption corona charger 5c for electrostatically attracting a transfer sheet, and
Adsorption roller 5g facing this adsorption corona charger 5c
And inner corona charger 5d and outer corona charger 5e
A transfer material carrying sheet 5f as an image carrying body made of a dielectric sheet such as polycarbonate in the peripheral opening area of the transfer drum 5a, having a separating corona charger 5h and a transfer peeling sensor 5i. It is stretched integrally in a shape.

The transfer paper carried on the transfer material carrying sheet 5f is charged by the transfer brush charger 5b by rotating the transfer drum 5a, and the toner on the photosensitive drum 1 is rotated by rotating the transfer drum 5a once. The image is transferred to the transfer paper carried on the transfer material carrying sheet 5f. When the transfer of the toner image of the desired color to the transfer paper is completed in this way, the transfer paper is separated from the transfer drum 5a by the separating claw 8a.
a, separation push-up roller 8b and separation corona charger 5
After separation by the action of h, the toner image on the surface is fixed by the heat roller fixing device 9, the toner image is discharged onto the discharge tray 10 and is used as a full-color image.

Further, in order to prevent the powder such as toner (developer) from adhering to the transfer material carrying sheet 5f and the oil on the transfer paper from adhering, the fur brush 1
Cleaning by the action of the backup brush 15 facing the fur brush 14 via the sheet 4 and the transfer material carrying sheet 5f, and the backup brush 17 facing the oil removing roller 16 via the oil removing roller 16 and the transfer material carrying sheet 5f. To do. Such cleaning is usually performed before or after image formation, and is performed whenever a jam (paper jam) occurs.

Further, the transfer drum 5a operates the eccentric cam 25 at a desired timing to move the transfer drum 5a.
The gap between the transfer material carrying sheet 5f and the photosensitive drum 1 can be arbitrarily set by operating the cam follower 5j that is integrated with the transfer material carrying sheet 5f. The distance from the drum 1 is the longest.

Further, in the structure of the transfer material conveying system for forming images on both sides of the transfer paper, when the transfer paper is discharged from the heat roller fixing device 9, the transfer paper is not conveyed to the tray 10 but conveyed vertically. A transport path switching guide 19 that switches to guide to the path 20, a transport system that guides the transfer sheet to the reversing path 21a through the transport vertical path 20, and a transfer sheet that is once fed to the reversing path 21a. Reversing roller 21b with the rear end as the leading end and retracting in the opposite direction to the fed direction
And an intermediate tray 22 for accommodating the transfer paper ejected by the reversing roller 21b.

Next, the operation will be described with reference to FIG.

When the mode key is set to the magnified continuous shooting mode and the copy key (not shown) is pressed, in the magnified continuous copying of the partial originals a1 and a2 shown in FIG. 3A (steps ST1 and ST2). Then, the process proceeds to step ST3 to perform normal image formation. That is, the partial original a1 of the original 30 placed on the original table glass 31 in the reader unit R
Is optically scanned by the exposure lamp 32. Then, the reflected light image from the partial document a1 is condensed on the full color sensor 34,
Obtain a color separation image signal. This color-separated image signal is subjected to image forming processing by a video processing unit via an amplifier circuit and sent to a printer section P.

In the laser exposure optical system 3, the reader unit R
The image signal from is first converted into an optical signal (laser light) E for image scanning exposure by the laser output section. Then, the converted laser light E is reflected by the polygon mirror 3a, passes through the lens 3b and the mirror 3c, and is projected onto the charged surface of the photosensitive drum 1.

At the time of forming an image in the printer section P, the photosensitive drum 1 is rotated in the direction of arrow R1 and the surface charge is removed by the pre-exposure lamp 11, and then the charger 2 uniformly charges the negative charge. After that, the photosensitive drum 1 is irradiated with the laser light E for each separated color to form an electrostatic latent image.

Next, a predetermined developing device corresponding to the laser beam for each separated color is operated to develop the electrostatic latent image on the photosensitive drum 1, and a negative resin whose base is resin is formed on the photosensitive drum 1. A charged toner is carried to form a toner image (visible image). At this time, each of the developing devices 4y, 4c, 4m, 4bk has a corresponding eccentric cam 24y, 24c, 24m, 24b.
The photosensitive drum 1 is selectively operated according to each separated color by the operation of k.
Approach.

Further, the transfer paper carried from the transfer material cassette 7 through the carrying system is carried on the transfer drum 5a by the transfer material carrying sheet 5f. When the transfer paper is supplied to the position facing the photosensitive drum 1 as the transfer drum 5a is rotated, the transfer brush charger 5
By b, the toner image on the photosensitive drum 1 is transferred onto the transfer paper, and copy images b1 and b2 as shown in FIG. 3B are separately formed.

After that, the photosensitive drum 1 after the toner image transfer
For cleaning the residual toner on the surface with a cleaning device 6 including a cleaning blade and a squeegee sheet, the toner is provided for another image forming step.

In the case of full-color image formation, when the transfer of four color toner images is completed by repeating the above steps, the transfer paper is separated from the transfer drum 5a by the separation claw 8a and the separation push-up roller 8.
b and separated by the action of the separation corona charger 5h,
The sheet is discharged to the sheet discharge tray 10 via the heat roller fixing device 9.

In this way, the enlarged continuous copying of the partial original a1 and the partial original a2 shown in FIG.
Copy images b1 and b2 as shown in (b) are carried on the transfer paper. As a result, even if the original document 30 has a uniform density in practice, the photosensitive drum 1 may be replaced by the corona charger 2 and the developing device 4.
When the developing rollers of y, 24c, 24m, and 24bk are eccentric, the copy images to be continuously enlarged are
Due to uneven charging due to the charging device, uneven development due to the developing device, etc.
For example, as shown in (b), the density gradient is such that the density on the front side in the sheet width direction of the transfer paper (the front side in the longitudinal direction of the transfer paper) becomes dark and the density on the back side (the back side in the longitudinal direction) becomes light. Will be the image that occurred.

Further, the partial original a3 shown in FIG.
Enlarged continuous shooting copy of a4 (step ST4, step ST
In 5), the process proceeds to step ST6. That is, in the reader unit R, the partial originals a3 and a4 of the original 30 placed on the original table glass 31 are optically scanned by the exposure lamp 32, respectively. Partial original a3 and partial original a
The reflected light image from No. 4 is focused on the full-color sensor 34 to obtain a color-separated image signal. This color-separated image signal is subjected to an image forming process including a process of rotating the image by 180 ° by a video processing unit via an amplifier circuit, and is sent to the printer section P.

In the laser exposure optical system 3, the image is
The image signal from the reader unit R rotated by 0 ° and subjected to the image forming process is converted into a laser beam E for image scan exposure at the laser output unit. Then, the converted laser light E is reflected by the polygon mirror 3a, passes through the lens 3b and the mirror 3c, and is projected onto the charged surface of the photosensitive drum 1.

At the time of forming an image in the printer section P, the photosensitive drum 1 is rotated in the direction of arrow R1, the surface charge is removed by the pre-exposure lamp 11, and then the charger 2 uniformly charges the negative charge. Then, the photosensitive drum 1 is irradiated with the laser light E for each separated color to form an electrostatic latent image.

Next, the predetermined developing devices 4y, 4c, 4m and 4bk corresponding to the laser light E for each separated color are operated,
The electrostatic latent image on the photosensitive drum 1 is developed to form a negatively charged toner image (visible image) on the photosensitive drum 1 using resin as a base.

Further, the transfer paper conveyed from the transfer material cassette 7 through the transfer system is carried on the transfer drum 5a by the transfer material carrying sheet 5f. Then, the transfer paper is supplied to a position facing the photosensitive drum 1 as the transfer drum 5a is rotated, and the toner image on the photosensitive drum 1 is transferred by the transfer brush charger 5b. Copy images b3 and b4 as shown in (b) are formed separately. That is, an image is formed in which a density gradient is generated such that the density on the front side of the transfer paper in the paper width direction is high and the density on the back side is light. Therefore, when the enlarged and continuously copied copy images b1, b2, b3, and b4 are pasted together, as shown in FIG. 3C, a copy image in which the density difference at the joint is not noticeable is obtained.

After that, the photosensitive drum 1 after the toner image transfer
For cleaning the residual toner on the surface with a cleaning device 6 including a cleaning blade and a squeegee sheet, the toner is provided for another image forming step.

In the case of full-color image formation, when the transfer of four color toner images is completed by repeating the above steps, the transfer paper is separated from the transfer drum 5a by the separation claw 8a and the separation push-up roller 8.
It is separated by the action of b and the separation charging device 5h, and is discharged to the discharge tray 10 via the heat roller fixing device 9.

FIG. 3B shows an enlarged continuous copy in which copy images b1 to b4 obtained by applying the present invention are joined together as shown in FIG. Was obtained.

When images are formed on both sides, the tray 10 is used when the transfer paper is discharged from the heat roller fixing device 9.
The transfer path switching guide 19 is switched so as not to be conveyed to the reverse path 21a via the vertical transfer path 20 and the transfer sheet is temporarily stored in the reverse path 21a. After that, the reversing roller 21b is rotated in the reverse direction, and the transfer sheet is retracted in the direction opposite to the fed direction with the trailing end of the fed sheet being the leading end, and stored in the intermediate tray 22. <Second Embodiment> When a plurality of transfer papers enlarged and copied according to the first embodiment are pasted together to form a series of copy images, a joint due to a difference in density between adjacent transfer papers cannot be seen. Therefore, depending on the copy image, the arrangement for attaching the transfer sheets cannot be known. For this reason, an arrangement regulation mark such as a number or a letter as shown in FIG. 4 for regulating the arrangement of the adjacent transfer sheets is provided outside the toner image forming area (margin portion) of the transfer sheet carrying the visible image. To do so. The placement regulation mark is engraved by a mark engraving means (not shown) built in the video processing unit. This makes it easier to perform the work for bonding. <Third Embodiment> In place of the arrangement restriction marks such as numbers and characters in the second embodiment, alignment marks such as registration marks as shown in FIG. , The transfer paper carrying the visible image should be superposed correctly. That is, an alignment mark for aligning the positions of the transfer papers adjacent to each other is formed by the mark engraving means built in the video processing unit in the margin portion serving as the joint of the transfer papers. This makes it possible to further facilitate the bonding work. Also,
By combining the arrangement regulation mark of the second embodiment and the alignment mark of this embodiment, the bonding work can be further facilitated.

[0051]

As described above, according to the present invention,
Toner image forming means for forming a toner image based on image information is provided on the surface of the image carrier, and a toner image obtained by dividing one image information into a plurality of pieces is transferred to each different transfer material to form a series of images. The transfer materials after the toner image formation are connected in the paper width direction and the above-mentioned 1 is formed.
Toner formed on one transfer material by the control unit when forming an enlarged toner image corresponding to one image information
The orientation of the toner image formed on the other transfer material with respect to the image
Is rotated 180 ° around the center of the other transfer material
Since it was controlled to be formed by
It is possible to make the density differences at the joints of the transfer materials substantially the same, and to make the density differences at the joints inconspicuous.

[Brief description of drawings]

FIG. 1 is a front view showing a schematic configuration of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating an image forming method during enlarged continuous shooting according to the first embodiment of the present invention.

3A and 3B show a case where a document is enlarged and continuously copied by the image forming apparatus of the present invention, FIG. 3A is a diagram showing the document, and FIG.
FIG. 6 is an explanatory diagram showing enlarged continuous copying, and FIG. 7C is a diagram showing a state in which the copies are pasted together.

FIG. 4 is a diagram in which reference numerals are added to the margins of the transfer sheet on which the visible image of the present invention is formed.

FIG. 5 is a diagram in which a mark is added to a margin of a transfer sheet on which a visible image of the present invention is formed.

6A and 6B show a case where a document is enlarged and continuously copied by a conventional image forming method, FIG. 6A is a diagram showing a document, FIG. 6B is an explanatory diagram showing enlarged and continuous copying, and FIG. It is a figure which shows the combined state.

[Explanation of symbols]

1 Image carrier (photosensitive drum)

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-325905 (JP, A) JP-A-8-46774 (JP, A) JP-A-2-137071 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G03G 15/36 G03G 21/00 370-540 G03G 21/14 G03G 15/00 303 H04N 1/38-1/393

Claims (5)

(57) [Claims] 1. A toner image in which a rotatable image carrier and a toner image forming unit for forming a toner image based on image information on the surface of the image carrier are provided, and one image information is divided into a plurality of toner images. An image forming apparatus configured to form a series of images by transferring a plurality of transfer materials to each other to form a series of images, wherein the one image information is divided into a plurality of toner images in the paper width direction. Is formed on one transfer material and the other transfer material to form an image , and
The transfer material and the other transfer material are connected in the paper width direction, and
When an enlarged toner image corresponding to one image information is formed, the toner image formed on one transfer material is
The orientation of the toner image formed on the transfer material of
An image forming apparatus, comprising: a control unit that controls the toner image forming unit so that the toner image is formed in a state of being rotated by 180 ° with respect to the center . 2. The image forming apparatus according to claim 1, wherein the toner image forming unit is constituted by a video processing unit. 3. An arrangement regulation mark for regulating the arrangement of the transfer material is formed outside the toner image forming area which is a joint of the transfer materials so as to form a series of enlarged toner images by bonding a plurality of transfer materials. The image forming apparatus according to claim 1 or 2, wherein the image forming apparatus is provided. 4. An alignment mark for aligning the positions of the transfer materials is formed outside the toner image forming area which is a joint of the transfer materials to form a series of enlarged toner images by bonding the plurality of transfer materials. The image forming apparatus according to claim 1 or 2, wherein: 5. An arrangement regulation mark for regulating the arrangement of the transfer material in order to form a series of enlarged toner images by adhering a plurality of transfer materials to each other outside the toner image forming area which is a joint of the transfer materials, The image forming apparatus according to claim 1 or 2, wherein an alignment mark for aligning the position is provided.