JP2023037958A - image forming system - Google Patents

Abstract

To solve the problem that when applying a varnish coat to both surfaces of a recording material, a conveyance path for returning a sheet from a varnish coater to a printer body is required for each optional apparatus which may be connected between the printer body and the varnish coater, in addition, there is a possibility that image unevenness will occur when a toner image is transferred again onto a recording material on which a varnish coating treatment has been applied on one side.SOLUTION: A varnish coating device includes an inversion conveyance path for reversely conveying a recording material, and after image forming is applied on both sides of a sheet by an image forming apparatus, varnish coating is applied on both sides of the sheet by the varnish coating device.SELECTED DRAWING: Figure 1

Description

The present invention relates to an image forming system for varnishing a recording material on which a toner image is formed.

An electrophotographic image forming apparatus generally includes a plurality of paper feed cassettes capable of conveying recording materials, and can arbitrarily select various recording materials of different sizes and types for printing. Therefore, in recent years, we have entered the production market, where offset presses were the mainstream until now, by taking advantage of our ability to handle small lots and the features of variable printing.

In addition, varnish coating is applied to the surface of an output material on which a toner image has been fixed by an electrophotographic image forming apparatus for the purpose of adding gloss to the output material, protecting the surface, or decorating the output material. Surface processing by equipment has attracted attention.

For example, Patent Literature 1 discloses a technique related to a varnish coating device. Further, Japanese Patent Application Laid-Open No. 2002-200001 discloses a technique of post-processing an output product output by an electrophotographic image forming apparatus using a varnish coating device.

JP 2007-176044 A JP 2011-145314 A

2. Description of the Related Art An electrophotographic image forming apparatus capable of double-sided printing is connected to various optional devices for performing various post-processing on output materials output from the image forming apparatus. For example, an inserter that inserts the cover page when outputting a booklet, a stacker that accommodates a large amount of output, a folding machine that performs V-folding, Z-folding, C-folding, etc. for outputting A finisher or the like that performs staple sorting or the like can be connected.

In addition, a puncher that punches holes in the printed matter, a trimmer that cuts the edges of the printed matter, an inspection device that detects printing defects by reading the image of the printed matter, and the above optional devices are connected inline. buffer unit for These optional devices can not only be connected to the image forming apparatus individually, but also can be connected simultaneously in various combinations.

In an image forming apparatus to which various optional devices as described above are connected, when both surfaces of a recording material are to be coated with varnish inline, one surface of the recording material is subjected to image formation processing and varnish coating processing. I had to invert it. In addition, a conveying path for returning the recording material from the varnish coating device to the image forming device after the varnish coating process is required.

However, as described above, various optional devices may be arranged between the image forming apparatus and the varnish coating device. A conveying path is required to return the material. As a result, the size and cost of the image forming apparatus main body and optional devices are increased.

Further, in an electrophotographic image forming apparatus, since a toner image is electrostatically transferred onto a recording material, the electrical resistance of the recording material differs between the varnish-coated area and the non-varnished area. . Therefore, image unevenness may occur when a toner image is transferred again to a recording material that has been varnished on one side. In particular, in the case of spot varnish coating, in which arbitrary areas of the recording material are coated with varnish, this problem becomes significant.

The present invention has been made in view of the above problems, and can suppress unnecessary cost increases for other optional devices, and can suppress the occurrence of image unevenness caused by performing varnish coating processing on both sides of a recording material. An object of the present invention is to provide an image forming system.

An image forming system according to the present invention for achieving the above objects is provided by an image forming unit for forming an image on a recording material, and reversing the recording material on which the image is formed on the first surface by the image forming unit, an image forming apparatus having a first reverse conveying path for conveying a recording material to the image forming unit so that an image is formed on a second surface opposite to the first surface; a varnish coating unit for coating the surface of the recording material coated with varnish; and a second reversing conveying path for conveying the recording material to the varnish coating section so that the recording material is coated with varnish.

According to the present invention, it is possible to suppress unnecessary cost increases for various optional devices connected to an electrophotographic image forming apparatus, and to suppress the occurrence of image unevenness when performing varnish coating processing on both sides of a recording material. can be done.

Schematic diagram showing an example of a double-sided image forming system according to the present embodiment. Schematic diagram showing an example of an image forming station according to the present embodiment Explanatory drawing showing the transport path of the recording material P according to the present embodiment.

Preferred embodiments of the invention are described in detail below by way of example with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment are not intended to limit the scope of the present invention only to them. do not have.

A double-sided image forming system according to the present invention will be described below with reference to the drawings. As shown in FIG. 1, the double-sided image forming system of this embodiment includes an image forming apparatus 100 that forms double-sided images on a recording material, an inspection apparatus 200 that reads and inspects the images on the recording material, and both sides of the recording material. A varnish coating device 300 capable of performing varnish coating is sequentially connected to the .

<Image forming apparatus>
The image forming apparatus 100 of this embodiment is a four-color full-color printer using an electrophotographic process. Specifically, as shown in FIG. 1, four image forming stations Pa, Pb, Pc, and Pd are arranged in series in the image feeding direction.

The image forming station will be described below. FIG. 2 shows a configuration common to image forming stations Pa, Pb, Pc, and Pd. The image forming station includes a photosensitive drum 140 as an image carrier, a charging device 141, an exposure device 142, a developing device 143, a cleaning device 144, a replenishing device (not shown) for replenishing toner to the developing device, and a primary transfer device 145. ing.

A rotationally driven photosensitive drum 140 is charged by a charging device 141, ie, a charging roller, bias-supplied from a high-voltage power supply.

The photosensitive drum 140 charged as described above then forms an electrostatic latent image on the drum surface by the exposure device 142 . The exposure device 142 consists of a light source device and a polygon mirror (not shown), and scans the laser light emitted from the light source device by rotating the polygon mirror. The scanning light beam is deflected by a plurality of reflecting mirrors and condensed on the generatrix of the photosensitive drum 1 by an fθ lens for exposure. can be formed.

The electrostatic latent image formed on the photosensitive drum 140 then faces the developing device 143, and the latent image on the photosensitive drum is sequentially formed according to the potential difference between the high voltage bias applied to the developing sleeve and the surface potential of the photosensitive drum. A toner image is formed by developing with toner. Here, in the developing device 143, a two-component developer in which yellow, magenta, cyan, and black non-magnetic toner and magnetic carrier are mixed at a predetermined mixing ratio corresponding to the image forming stations Pa, Pb, Pc, and Pd, respectively. is filled with a predetermined amount.

A toner cartridge, which is a replenishing device for replenishing toner to the developing device, is filled with non-magnetic toner, and is replenished to the developing device according to the amount of non-magnetic toner used from within the developing device.

The driving of the photosensitive drum 140, the polygon in the exposure device 142, the development sleeve in the development device 143, and the stirring roller in the development device is controlled by a control unit. Similarly, bias application to the charging device 141, the developing device 143, and the primary transfer roller 145 is also controlled by the controller.

A toner image formed on the surface layer of the photosensitive drum by the developing device 143 is formed on the intermediate transfer belt 101 by the transfer device 145 . On the other hand, primary transfer residual toner and the like remaining on the photosensitive drum 1 are collected by the cleaning device 144 .

Hereinafter, the process until the images generated at the image forming stations Pa, Pb, Pc, and Pd are output from the image forming apparatus will be described with reference to FIG.

The toner images formed by the image forming stations Pa, Pb, Pc, and Pd and transferred onto the intermediate transfer belt 101 are transferred to the recording material conveyed from the recording material cassette 103 through the registration rollers 110 in the secondary transfer device 102 . Secondarily transferred to P. After that, the toner image is fixed by heating and pressing in the fixing unit 104, and then passed through the conveying path 111 and discharged from the image forming apparatus 100 as a recorded image. Further, an intermediate transfer belt cleaning device 105 for cleaning fog toner, secondary transfer residual toner, and the like adhering to the surface of the intermediate transfer belt 101 is always located downstream from the secondary transfer position onto the recording material P in the direction in which the intermediate transfer belt advances. is abutted and cleaned. The image forming stations Pa, Pb, Pc, Pd and the intermediate transfer belt 101 are an example of an image forming section.

In the case of this embodiment, the image forming apparatus 100 can form images on both sides of the recording material P. FIG. When forming an image on one side of the recording material P, the recording material P that has passed through the fixing unit 104 passes through the conveying path 111 and is discharged outside the image forming apparatus 100 . On the other hand, when images are formed on both sides of the recording material P, the recording material P that has passed through the fixing unit 104 passes through a conveying path 112, a reversing path 113 as a reversing conveying path, and a double-sided conveying path 114, and the front and back of the recording material P are switched. . Then, an image is formed on the second side of the recording material P opposite to the first side through the same process as in the case of forming the image on the first side.

<Inspection device>
As shown in FIG. 1, the inspection apparatus 200 of this embodiment includes a color sensor 201 as a first inspection section and an image reading section 202 as a second inspection section. The color sensor 201 includes, for example, a light source that irradiates the recording material P with white light, a diffraction grating that resolves the reflected light from the recording material P by wavelength, and a plurality of imaging elements that measure the intensity of the reflected light for each wavelength. (line sensor) and measures the color of the image on the recording material P.

An image reading unit 202 as a reading unit has, for example, a front surface sensor 202a and a rear surface sensor 202b, which are contact image sensors (CIS) equipped with CMOS as imaging elements, and can read image information from both sides of the recording material P. is.

The inspection apparatus 200 is provided with a conveying path 203 for conveying the recording material P received from the image forming apparatus 100 to the outside of the inspection apparatus 200, and an inspection path 204 on which a color sensor 201 and an image reading unit 202 are arranged. ing. The inspection path 204 branches from the conveying path 203, passes under the conveying path 203, and joins the conveying path 203 again. A switching member 205 for switching the conveying path of the recording material P between the conveying path 203 and the inspection path 204 is arranged at the branching portion of the conveying path 203 and the inspection path 204 .

A discharge tray 206 for discharging the recording material P is provided above the inspection device 200 . The discharge path 207 branches off from the transport path 203 on the downstream side of the junction of the transport path 203 and the inspection path 204 in the transport direction of the recording material P in the transport path 203 .

A switching member 208 for switching the conveying path of the recording material P between the discharge path 209 and the discharge path 207 is arranged at the branching portion of the conveying path 203 and the discharge path 207 . The recording material P guided to the discharge path 209 by the switching member 208 is discharged outside the inspection device 200 by a pair of conveying rollers provided in the conveying path, and guided to the discharge path 207 by the switching member 208. P is discharged to the discharge tray 206 . The switching members 205 and 208 are flap-shaped guide members.

The inspection device 200 performs an inspection operation for detecting whether the recording material P has an abnormal image. This inspection operation is performed by a control unit (not shown) using reference data used for image formation by the image forming apparatus 100 and information acquired from the recording material P passing through the inspection path 204 by the color sensor 201 and the image reading unit 202 . It is done by comparing. The data used for image formation by the image forming apparatus 100 refers to data read from a document by a scanner device or data received from an external computer. An image without image defects means, for example, high color reproducibility, image position and geometric shape with respect to the recording material P satisfying certain conditions, and abnormalities such as density unevenness, color skipping, and staining. Refers to an image that is within tolerance.

When an inspection operation is performed on a recording material P on which an image has been formed by the image forming apparatus 100, the recording material P that has been determined to have no image defect (accepted) is guided to the conveying path 203 and passed through the discharge path 209 outside the apparatus. It is discharged outside the inspection device 200 . Also, the recording material P determined to have an image defect (failed) is guided to a discharge path 207 and discharged to a discharge tray 206 .

Note that the color sensor 201 and the image reading unit 202 are both examples of inspection means, and other inspection means may be used. In addition, inspection items in the inspection operation are not particularly limited. For example, the image data read from the recording material P by the image reading unit 202 may be analyzed to check whether the character information printed on the recording material P (for example, the address and name of the postal item) is correct. good.

<Varnish coating device>
As shown in FIG. 1, the varnish coating device 300 of this embodiment is a general roll-type varnish coater that applies varnish liquid to the entire surface of the recording material. The varnish application device 300 includes an application roller 301 and a backup roller 302 forming an application nip portion N for applying varnish to the recording material P, a feed roller 303, a regulation roller 304, a varnish liquid storage portion 305, and a curing device. 306. The curing device 306 is composed of a varnish liquid curing unit 307 and a conveying section 308 . The application roller 301, the backup roller 302, the feed roller 383, the regulation roller 304, and the storage section 305 are examples of the varnish application section.

Here, each of the rollers 301 to 304 is configured to be rotatably driven by driving means (not shown). Furthermore, the contact state or separation distance between the feed roller 303 and the regulation roller 304, and between the feed roller 303 and the application roller 301 can be arbitrarily changed by an adjustment mechanism (not shown). The curing unit 307 is UV irradiation means or non-contact heating means so that the varnish liquid can be cured or dried according to the type of the varnish liquid.

Next, the varnish liquid application configuration of the varnish application device 300 will be described. The varnish liquid storage part 305 stores the varnish liquid supplied by the feed roller 303 . The storage part 305 is a case that opens upward and stores the varnish liquid therein. A portion of the surface of the feed roller 303 is immersed in the varnish liquid stored inside the case of the storage portion 305 .

The varnish liquid is pumped up from the reservoir 305 by the rotation of the feed roller 303, passes through the facing portion of the feed roller 303 and the regulation roller 304, and then moves to the surface of the application roller 301 due to the contact between the feed roller 303 and the application roller 301. .

Here, by adjusting at least one of the rotation speed of the feed roller 303, the separation distance between the feed roller 303 and the regulation roller 304, and the contact pressure between the feed roller 303 and the application roller 301, the varnish liquid applied to the application roller 301 can be adjusted. can be adjusted.

The film thickness of the varnish liquid applied to the recording material P at the coating nip portion N can be adjusted by using the above coating structure and the mechanism for adjusting the coating amount of the varnish liquid.

In the case of this embodiment, the varnish application device 300 can apply the varnish liquid to both surfaces of the recording material. When the varnish liquid is applied to the first surface of the recording material, the recording material P that has passed through the curing device 306 is discharged outside the varnish coating device 300 through the discharge path 311 . On the other hand, when the varnish liquid is applied to both sides of the recording material P, the recording material P is passed through a conveying path 312 , a reversing path 313 , and a double-sided conveying path 314 so that the front and back of the recording material P are reversed. The recording material P whose front and back sides have been reversed undergoes the same process as when the varnish liquid is applied to the first surface, and the varnish liquid is also applied to the second surface opposite to the first surface. Then, the recording material P coated with the varnish liquid on both sides passes through the curing device 306 again and is discharged outside the varnish coating device 300 through the discharge path 311 .

<Conveyance path of recording material P>
Next, the conveying path for applying varnish on both surfaces of the recording material P in the configuration of this embodiment will be described with reference to FIG.

When a job for applying varnish to both surfaces of the recording material P is started, the recording material P in the recording material cassette 103 is conveyed to the registration rollers 110 . At a predetermined timing after the toner image is formed on the intermediate transfer belt 101, the recording material P is conveyed from the registration rollers 110 to the secondary transfer device 102, and one surface (first surface) of the recording material P is coated with unfixed toner. An image is formed.

After that, the unfixed toner image formed on the first surface of the recording material P is fixed by the fixing unit 104 . Next, the recording material P is conveyed to a conveying path 112 and sent to a reversing path 113 . The recording material P sent to the reversing path 113 is switchback-conveyed toward the double-sided conveying path 114, whereby the first surface of the recording material P on which an image is formed and the surface on which no image is formed (second surface). can be replaced with

The recording material P whose first side and second side have been exchanged passes through a double-sided conveying path 114 and is conveyed toward the registration rollers 110. After undergoing the same process as in forming an image on the first side, the recording material P is transferred to the secondary transfer device 102. A toner image is also formed on the second surface of the recording material P at . After that, the toner image formed on the second surface of the recording material P is fixed by the fixing unit 104 . Then, the recording material P with the toner images fixed on both sides is discharged out of the image forming apparatus 100 through the discharge conveying path 111 .

Next, upon receiving the recording material P discharged from the image forming apparatus 100, the inspection apparatus 200 conveys the recording material P to a conveying path 203 and an inspection path 204, and checks the images on the first and second sides of the recording material P. Read and inspect for image defects. After that, if the recording material P has no image defects, it returns to the conveying path 203 and is discharged outside the inspection device 200 through the discharge path 209 .

Next, the varnish coating device 300 receives the recording material P discharged from the inspection device 200, conveys the recording material P to the coating nip portion N through the registration rollers 310, and applies varnish to the second side of the recording material P. FIG. After that, the varnish applied to the recording material P is cured by the curing device 306 , and then conveyed to the conveying path 312 and sent to the reversing path 313 .

The recording material P sent to the reversing path 313 is switchback-conveyed toward the double-sided conveying path 314, so that the varnished second side of the recording material P and the non-varnished first side are exchanged. be done. The recording material P whose second side and first side are exchanged passes through a double-sided conveying path 314 and is conveyed toward the registration rollers 310, and varnish is applied to the first side of the recording material P at the coating nip portion N. . After that, the varnish applied to the recording material P is cured by the curing device 306 , and then discharged out of the varnish coating device 300 through the discharge path 311 .

As described above, in the configuration of the present embodiment, image formation and varnish coating can be performed on both sides of the recording material P by reversing the recording material P in each of the image forming apparatus 100 and the varnishing apparatus 300. . Therefore, the inspection device 200 arranged between the image forming device 100 and the varnish coating device 300 does not require a conveying path for returning the recording material P from the varnish coating device 300 to the image forming device 100. unnecessary cost increase can be avoided.

In the configuration of this embodiment, the inspection device 200 is illustrated as an optional device arranged between the image forming device 100 and the varnish coating device 300, but this is not the only option. In other words, as long as it is an optional device arranged between the image forming apparatus and the varnish coating device, it can be applied even when a plurality of types of optional devices are connected at the same time. For example, an inserter for inserting a cover page or the like when outputting a booklet or the like, and a cleaning device for removing foreign substances adhering to the surface of a recording material before varnishing are good examples.

Also, the recording material P whose both sides are coated with varnish is conveyed again to the conveying path 312 and sent to the reversing path 313 . Then, the recording material P may be discharged from the varnish coating device 300 after the first side and the second side of the recording material P are replaced again by switchback conveyance toward the discharge path 311 outside the apparatus. In this case, the orientation of the recording material P when discharged from the varnish coating device 300 (first side up or second higher face) can be selected as appropriate. Optional devices connected downstream of the varnish coating device 300 include a binder that binds recording materials, a folding machine that folds recording materials, and a finisher that staples and sorts recording materials. . Optional devices connected further downstream of the varnish coating apparatus 300 include a puncher for punching holes in the recording material, a trimmer for cutting the recording material, and the like.

The means for applying the varnish liquid to the recording material P is not limited to the roll type using the application roller 301 and the backup roller 302, and for example, a line head that ejects varnish by an inkjet method may be used. When a line head is used, spot coating for selectively applying varnish to arbitrary positions on the recording material P is possible.

Here, in an electrophotographic printer, since a toner image is electrostatically transferred onto a recording material, the electrical resistance of the recording material differs between a varnished area and a non-varnished area. Therefore, image unevenness may occur when an image is transferred to the back surface of the spot-coated recording material. However, according to the present invention, after images are formed on both sides of the recording material, both sides of the recording material are coated with varnish by the varnish coating device, so that unevenness in the image due to the varnish coating on both sides can be suppressed. can be done.

100 Image Forming Device 101 Intermediate Transfer Belt 102 Secondary Transfer Device 103 Recording Material Cassette 104 Fixing Section 105 Transfer Intermediate Transfer Belt Cleaning Device 110 Registration Roller 111 External Discharge Path 112 Conveyance Path 113 Reversing Path 114 Double Side Conveyance Path 200 Inspection Device 201 Color Sensor 202 Image reading unit 203 Conveyance path 204 Inspection path 205 Switching member 206 Discharge tray 207 Discharge path 208 Switching member 209 External discharge path 300 Varnish coating device 301 Coating roller 302 Backup roller 303 Feed roller 304 Regulating roller 305 Storage unit 306 Curing device 307 Curing Means 308 Conveying Section 310 Registration Roller 311 Outside Discharge Path 312 Conveying Path 313 Reversing Path 314 Duplex Conveying Path Pa, Pb, Pc, Pd Image Forming Station N Coating Nip

Claims (6)

An image forming unit that forms an image on a recording material, and the recording material on which an image is formed on a first surface by the image forming unit is reversed, and an image is formed on a second surface opposite to the first surface. an image forming apparatus having a first reverse conveying path for conveying the recording material to the image forming unit;
a varnish applying unit that applies varnish to the surface of the recording material on which an image has been formed by the image forming apparatus; a second reversing transport path for transporting the recording material to the varnish coating unit so that the second surface opposite to the second surface is coated with varnish;
An image forming system comprising: The varnish application unit has an application roller that applies varnish to the recording material, and a backup roller that conveys the recording material together with the application roller.
2. The image forming system according to claim 1, wherein: The varnish application unit has a line head that injects varnish onto the recording material.
2. The image forming system according to claim 1, wherein: The varnish application device has a curing unit that cures the varnish applied to the recording material by the varnish application unit.
4. The image forming system according to claim 1, wherein: a reading unit provided between the image forming apparatus and the varnish coating device in the conveying direction of the recording material for reading an image formed on the recording material discharged from the image forming apparatus; and a recording material that has passed through the reading unit. to the varnish coating device; and a reading device comprising:
a control unit that compares the image data read by the reading unit with reference image data and detects an abnormal image;
5. The image forming system according to claim 1, wherein: The reading device has a discharge tray for discharging the recording material on which the abnormal image is detected by the control unit.
6. The image forming system according to claim 5, wherein:

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