JP2003122223A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose a means for surely forming an image on a deformed sheet having recesses and projections at the terminal edge of a tab paper sheet and other paper sheets. SOLUTION: A means for reading a sheet material position and an external shape is provided on a sheet material carrying path to correct the inclination of image information data, to correct the magnification of main scanning and sub scanning, to correct the position of the main scanning and the sub scanning, and to correct a margin on the basis of the read information.

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 for forming an image on a sheet material, for example.

[0002]

2. Description of the Related Art A conventional image forming apparatus has an image forming section for transferring an image onto a sheet material or the like, and when the sheet material is skewed, the angle of the image relative to the sheet material is relatively large. Since it will be transferred in a tilted state,
Various means are used to correct the skew of the conveyed sheet material.

For example, the sheet materials fed from the sheet material stacking section one by one by the sheet feeding section are once projected into a nip of a pair of registration rollers which is stopped adjacent to the upstream side of the sheet conveying in the image forming section. A method of correcting the hitting skew is often used.

Further, in the vicinity of the upstream side of the pair of conveying rollers, a plurality of shutter members capable of projecting and retracting into the sheet material conveying path are provided along the conveying rollers, and the tip of the sheet material is brought into contact with the protruding shutter member. There is also used a method in which skew feeding is corrected by the method, and the shutter member is retracted to convey the skew-corrected sheet material.

In any of these methods, skew feeding can be corrected by aligning the leading edge of the sheet in parallel with the nip line of the registration roller and the shutter member by the waist of the sheet. Further, two pairs of conveying rollers, which are arranged on the back side and the front side in the sheet material conveying direction and whose conveyance speed is variable, detect skew of the sheet material and detect the skew of the sheet material on the back side and the front side. There is also a method of correcting the skew of the sheet material by controlling the speed of the transport roller.

Apart from these methods, Japanese Patent Laid-Open No. 8-305
As disclosed in Japanese Patent Publication No. 098, there has been proposed a method of measuring the skew amount of a sheet material and forming an image in accordance with the skew amount of the sheet material.

[0007]

However, due to the increasing needs of users in recent years, the demand for various sheet materials has increased, and it has become important to perform good image registration. For example, in recent years, it has been strongly desired to support tab paper, which is one of the sheet materials for passing paper through an image forming apparatus (note that tab paper is
For the purpose of classification, it refers to a sheet material with tabs on the edges for entering headings, etc.), but the position of the tabs is not constant, and there are multiple tabs to make it easier to check the headings on the tabs. It is provided in a staggered manner.

For the sheet material having such a shape, the conventional skew feeding correcting means may not always work effectively. That is, when the tab portion is fed as the leading end in the transport direction, it is difficult to perform skew correction by the above-described conventional registration roller and shutter registration methods. In addition, it is difficult to form an image on a postcard having an uneven outer shape.

(Purpose) Therefore, an object of the present invention is to propose a means for surely forming an image on a deformed sheet material having an uneven shape on the edge of the sheet such as a tab sheet.

[0010]

According to another aspect of the present invention, there is provided an image forming apparatus for reading an outer shape of a sheet material on a sheet conveying path, image information, a position and an outer shape of the sheet material, and the sheet. And a means for correcting the image information based on the material position and outer shape information and forming an image on the sheet material.

According to a second aspect of the present invention, in the first aspect of the invention, the means for correcting the image information based on the outer shape information is image inclination correction, main scanning and sub-scanning magnification correction,
It is characterized in that the main scanning and sub-scanning position correction and margin correction are performed.

According to a third aspect of the present invention, in the second aspect, the image information, the sheet material position and the outer shape information are received, and the inclination correction of the image information, the main scanning and the sub-scanning are performed based on the read information. It is characterized by having means for individually performing magnification correction, main scanning and sub-scanning position correction, and margin correction.

The invention of claim 4 is characterized in that, in the invention of claim 1, the position of the center of gravity of the sheet material is aligned with the position of the image center.

(Operation) It has become possible to reliably form an image on a deformed sheet material having an uneven shape on the edge of the sheet, which has been difficult until now.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An image forming apparatus according to the present invention will be described below in more detail with reference to the drawings.

(Embodiment 1) A first embodiment of the present invention will be described with reference to FIGS.

First, the overall structure of the color image forming apparatus of this embodiment will be described with reference to FIG.

The color image forming apparatus of this embodiment has two cassette paper feed units 1 and 2 and one manual paper feed unit 3, and selectively selects from each of the paper feed stages 1, 2, and 3. The sheet material S is fed. The sheet material S is stacked on the cassettes 4 and 5 or the tray 6 of the molars 1, 2 and 3, and is picked up by the pickup roller 7 in order from the top. Then, the sheet material S fed by the pickup roller 7 is fed by a feed roller 8A as a conveying means.
Then, only the uppermost sheet material is separated by the separation roller pair 8 including a retard roller 8B as a separating means, and the separated sheet material is sent to the registration roller unit 12 which is stopped rotating.

In this case, the sheet material S fed from the cassettes 4, 5 having a long distance to the registration roller unit 12 is relayed to the plurality of conveyance roller pairs 9, 10, 11 and sent to the registration roller unit 12. A long intermediate transfer belt (endless belt) which is a transfer member is provided downstream of the registration roller unit 12.
13 'is stretched around a driving roller, a driven roller, and a tension roller, and the intermediate transfer belt 13' rotates clockwise in the drawing.

A secondary transfer roller pair 40 is provided at the secondary transfer portion T2. A plurality of photosensitive drums 14, 15, 16, 17 for forming and carrying color toner images of different colors are sequentially arranged on the upper surface of the horizontal portion of the intermediate transfer belt 13 'along the rotation direction of the intermediate transfer belt 13'. ing.

In the rotation direction of the intermediate transfer belt, the most upstream photoconductor drum 14 carries a magenta toner image, the next photoconductor drum 15 carries a cyan toner image, and the next photoconductor drum 16 is carried. Carries a yellow toner image, and the most downstream photosensitive drum 17 carries a black toner image.

In the color image forming apparatus of this embodiment, a plurality of originals (not shown) are sequentially set on the original table (platen glass) 19 at predetermined positions by the automatic original feeder 18. . Then, the document table 19
The image of the document set above (here, a color image) is read by the reading optical system 20. The read color image is decomposed into color components of magenta, cyan, yellow and black by the CCD element 21, and is temporarily stored in an image memory (not shown). The image information stored in the image memory is written by the writing optical system 22 including the laser scanner onto the photosensitive drums 14 to 17 which are sequentially rotated in the clockwise direction for each color component.

First, the projection of the laser beam L (M) based on the image of the magenta component is started on the uppermost photosensitive drum 14, and an electrostatic latent image is formed on the photosensitive drum 14. This electrostatic latent image is visualized by magenta toner supplied from the developing device 23.

Next, the projection of the laser beam L (C) based on the image of the cyan component is started on the photosensitive drum 15,
An electrostatic latent image is formed on the photosensitive drum 15. This electrostatic latent image is visualized by magenta toner supplied from the developing device 24.

Next, after a lapse of a predetermined time from the start of projection of the laser light L (M) on the photosensitive drum 15, the laser light L based on the image of the yellow component is formed on the photosensitive drum 16.
The projection of (Y) is started, and an electrostatic latent image is formed on the photosensitive drum 16. This electrostatic latent image is visualized by the yellow toner supplied from the developing device 25.

Next, after a lapse of a predetermined time from the start of projection of the laser light L (Y) on the photosensitive drum 16, the laser light L based on the image of the black component is formed on the photosensitive drum 17.
The projection of (B) is started, and an electrostatic latent image is formed on the photosensitive drum 17. This electrostatic latent image is visualized by the black toner supplied from the developing device 26.

In addition, around the photosensitive drums 14 to 17,
Primary chargers 27, 28, 29, 30 for uniformly charging the photoconductor drums 14-17, and a cleaner for removing toner adhering to the photoconductor drums 14-17 after the toner image transfer. 31, 32, 33, 34 and the like are installed.

The sheet material S sent from the registration roller section 12 and corrected in the skewed state is sent onto the intermediate transfer belt 13 'at the timing of aligning the positions of the toner image and the leading edge of the sheet material. The sheet material S sent to the intermediary transfer belt 13 ′ is transferred in the downstream direction by the intermediary transfer belt 13 ′, a transfer portion between the photoconductor drum 14 and the transfer charger 90, the photoconductor drum 15 and the transfer charge. The intermediate transfer belt 13 by sequentially passing through a transfer portion between the photosensitive drum 16 and the transfer charger 92, a transfer portion between the photosensitive drum 16 and the transfer charger 92, and a transfer portion between the photosensitive drum 17 and the transfer charger 93. 'The magenta, cyan, yellow, and black toner images overlaid are transferred at one time.

The sheet material S that has passed through the secondary transfer portion T2 is sent to a fixing roller pair 35 which constitutes a fixing device by an intermediate transfer belt 13 '. Then, the sheet material S is the fixing device 3
5 is overheated by the fixing roller 35A in the pressure roller 3
5B is pressed to fix the transferred toner image on the sheet surface. Sheet material S that has undergone the fixing process after passing through the fixing device 35
Is sent to the discharge roller pair 37 by the transport roller pair 36 and further discharged onto the discharge tray 38 outside the machine.

In this image forming apparatus, image formation in the double-sided mode is possible. Hereinafter, the configuration of the image forming apparatus will be further described along the flow of the sheet material S in the double-sided mode.

When the double-sided mode is designated, the fixing-processed sheet material S which has passed through the fixing roller pair 35 has a vertical pass 5
8 and sent to the reverse path 59. In this case, the flapper 60 opens the vertical path 58, and the fixing-processed sheet material S is transported by the transport roller pairs 36, 61, 62 and the reverse rotation roller pair 63.

The rear end of the sheet material S after the fixing process, which is conveyed in the direction of the arrow a by the pair of reverse rollers 63, is point P.
When the sheet passes through, the reverse rotation roller pair 63 reversely rotates, and the fixing-processed sheet material S is conveyed in the direction of the arrow b, with the rear end side as the leading end. By this operation, the toner image transfer surface of the fixing-processed sheet material S is on the upper side.

At the point P, the sheet material S can enter from the vertical path 58 to the reverse path 59, and the sheet material S can enter from the reverse path 59 to the vertical path 58.
A flapper 64 with a flexible sheet material that prevents the sheet material S from entering the vertical path 58 from the reverse path 59 and a detection lever 65 that detects that the rear end of the sheet material has passed the point P are provided. ing.

The fixed sheet material S conveyed in the direction of the arrow b by the reverse rotation of the reverse rotation roller pair 63 is fed by the re-feeding path 67.
It is then sent inside and is relayed by a plurality of re-feeding path in-conveyance roller pairs 68 and conveyance roller pair 11 and again sent to the registration roller pair 12 for image formation. The sheet material S having undergone the fixing process is sent to the intermediate transfer belt 13 ′ after the skewed state is corrected by the registration roller unit 12. Then, the second image formation is performed based on the image data stored in the image memory (not shown) in which the magnification correction in the main scanning direction and the sub-scanning direction is performed, and thereafter, the same process as the one-sided image formation is performed. Is discharged to the outside of the aircraft.

Next, the image position correction, which is a characteristic part of the present invention, will be described. FIG. 2 shows the registration roller unit 12
FIG. 3 is a detailed view of an image forming unit.

The registration roller unit 12 has a stepping motor 76 connected to the registration driving roller 12a and a line sensor 75 for detecting the shape and position of the sheet material before registration. When the sheet material S is conveyed from the paper feeding section, the line sensor 75 detects the shape and position of the sheet material S, and the CPU recognizes the shape based on the detection signal. When it is determined that the shape is plain paper (rectangular cut paper), the stepping motor 75 is controlled to correct the skew of the sheet material S, and the sheet is sent to the secondary transfer portion T2 of the intermediate transfer belt.

The flow of the sheet material S will be described with reference to FIG.

FIG. 3A shows the registration roller unit 1 when an image is formed on the first surface of the irregularly shaped sheet material S (tab sheet).
The line sensor 75 of No. 2 detects the shape and position of the irregularly shaped sheet material S, and the CPU recognizes the shape and the sheet material position based on the detection signal. When it is determined that the recognized shape is plain paper or an equivalent shape as shown in FIG. 3A, the irregularly shaped sheet material S is once abutted against the nip of the registration roller 12 to correct the skew and the secondary transfer portion is corrected. It is sent to T2 to form an image.

FIG. 3B shows that the irregularly shaped sheet material S (tab sheet) is reversed and an image is formed on the second surface. In this case, the line sensor 75 detects the shape and position of the irregularly shaped sheet material S, and the CPU detects the detected signal based on the detected signal.
Recognizes the shape and sheet material position. Since the tab portion of the irregularly shaped sheet material S is on the registration roller 12 side, the skew correction by the registration roller 12 is not performed, but the image data stored in the image memory (not shown) is corrected (skew correction,
Main scanning / sub-scanning position correction and main scanning / sub-scanning magnification correction) are performed, and the image is sent to the secondary transfer portion T2 to form an image.

FIG. 3C shows that an image is formed on the irregularly shaped sheet material S (cloud paper). In this case, the line sensor 75 detects the shape and position of the irregularly shaped sheet material S, and the CPU recognizes the shape and position of the sheet material based on the detection signal. In this case, the irregularly shaped sheet material S
The skew correction by the registration roller 12 is not performed, and the sheet is conveyed as it is, and the image data stored in the image memory (not shown) is corrected (skew correction, main scanning / sub scanning position correction, main scanning
Sub-scanning magnification correction and margin amount adjustment) are performed, and the image is formed by being sent to the secondary transfer portion T2.

Further, here, as shown in FIGS. 3D to 3G, the user can correct the image data stored in the image memory (not shown) by the external input / output device such as the operation unit. Alternatively, it is also possible to correct / edit the image data / shape data of the sheet material via a network such as a personal computer. When the rear end of the irregularly shaped sheet material S (cloud-shaped paper) passes through the line sensor 75, the sheet S is temporarily stopped, and the user performs the operations shown in FIGS.

First, the image information is subjected to inclination adjustment in a state where the center of gravity of the outer shape of the sheet material and the center of gravity of the image are aligned as shown in FIG. 3D, and the image position is sequentially arranged as shown in FIG. Adjustment (main scanning and sub scanning) is performed, and image magnification adjustment (main scanning and sub scanning) is performed as illustrated in FIG.
The margin amount is adjusted as shown in (g), and the secondary transfer portion T
2 and image formation is performed.

(Embodiment 2) A second embodiment of the present invention will be described with reference to FIGS.

In this embodiment, the intermediate transfer belt 1 of Embodiment 1 is used.
The difference is that a transfer belt 13 is used instead of No. 3 (FIG. 4). FIG. 5 is a detailed view of the registration roller unit 12 and the image forming unit. As shown in FIG. 6, the image position correction of the irregularly shaped sheet material S (cloud-shaped paper) is performed as shown in FIG.
Is the same as (g).

Further, in the first and second embodiments, the sheet material shape information is registered in advance, and the image data stored in the image memory (not shown) is based on this information and the information detected by the line sensor 75. It is also possible to perform correction (skew correction, main scanning / sub scanning position correction, main scanning / sub scanning magnification correction, margin amount adjustment). Further, here, the correction is performed for the irregularly shaped sheet material having the wavy edges, but it goes without saying that the sheet material of any shape can be applied. Finally, the flowchart in Embodiments 1 and 2 is shown in FIG.

[0046]

According to the present invention, it is possible to surely form an image on a sheet material having an irregular shape having an uneven shape on the edge side of the sheet, which has been difficult until now.

[Brief description of drawings]

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

FIG. 2 is a schematic diagram of Example 1.

FIG. 3 is a detailed skew feeding correction diagram in the first embodiment.

FIG. 4 is an overall configuration diagram of an image forming apparatus according to a second embodiment of the present invention.

FIG. 5 is a schematic diagram of Example 2.

FIG. 6 is a detailed skew correction diagram according to the second embodiment.

FIG. 7 is a flowchart of Examples 1 and 2.

[Explanation of symbols]

1, 2 paper feeder 3 Manual feed section 4,5 cassettes 6 trays 7 Pickup roller 8 Separation roller pair 8A feed roller 8B retard roller

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Claims (4)

[Claims] 1. A means for reading an outer shape of a sheet material on a sheet material conveying path, image information, a sheet material position and an outer shape, and correcting the image information based on the sheet material position and the outer shape information. An image forming apparatus comprising: a means for forming an image on a sheet material. 2. The means for correcting the image information on the basis of the outer shape information performs image inclination correction, main-scan and sub-scan magnification correction, main-scan and sub-scan position correction, and margin correction. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. 3. The image information and the sheet material position and outer shape information are received, and based on the read information, inclination correction of the image information, magnification correction of main scanning and sub scanning, position correction of main scanning and sub scanning. 3. The image forming apparatus according to claim 2, further comprising means for individually performing each of the blank margin corrections. 4. The image forming apparatus according to claim 1, wherein the center of gravity of the sheet material is aligned with the center of the image.