Image forming system

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

[Technical Field]

[0001] The present invention relates to an image forming system that applies a varnish coating process to a recording material on which a toner image has been formed. [Background technology]

[0002] Electrophotographic image forming apparatuses generally have multiple paper feed cassettes capable of transporting recording materials, allowing users to select and print on a variety of different sizes and types of recording materials. Taking advantage of their capabilities for small-lot production and variable data printing, these apparatuses have recently entered the production market, which was previously dominated by offset printing machines.

[0003] In addition, attention is being paid to surface processing using a varnish application device, which applies varnish to the surface of an output object on which a toner image has been fixed by an electrophotographic image forming device, in order to impart gloss to the output object, protect the surface, or decorate the output object.

[0004] For example, Patent Document 1 discloses a technique related to a varnish application device. Furthermore, Patent Document 2 discloses a technique for post-processing an output object output by an electrophotographic image forming apparatus using a varnish application device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-176044 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-145314 Summary of the Invention [Problem to be solved by the invention]

[0006] An electrophotographic image forming apparatus capable of double-sided printing can be connected to various optional devices for performing various post-processing operations on the output from the image forming apparatus, such as an inserter that inserts a cover page when outputting a booklet, a stacker that stores a large number of output documents, a folding machine that folds the output documents in V-folds, Z-folds, C-folds, etc., and a finisher that performs staple sorting on the output documents.

[0007] Other examples include a puncher that punches holes in the output, a trimmer that cuts the edges of the output, an inspection device that detects printing defects by reading the image of the printed material, and a buffer unit for connecting the above-mentioned optional devices inline. These optional devices can be connected to the image forming device individually or simultaneously in various combinations.

[0008] In an image forming apparatus connected to various optional devices as described above, when varnishing is performed inline on both sides of a recording material, it is necessary to turn over the recording material after the image forming process and varnishing process have been performed on one side of the recording material. Then, a transport path is required to return the recording material from the varnishing device to the image forming apparatus after the varnishing process.

[0009] However, as mentioned above, since various optional devices may be installed between the image forming apparatus and the varnish application device, all of these optional devices require a transport path to return the recording material from the varnish application device to the image forming apparatus, which increases the size and cost of the image forming apparatus and the optional devices.

[0010] Furthermore, in electrophotographic image forming devices, the toner image is electrostatically transferred to the recording material, resulting in differences in electrical resistance between the varnished and unvarnished areas of the recording material. Therefore, when a toner image is transferred to a recording material that has already been varnished on one side, image unevenness may occur. This problem is particularly pronounced in the case of spot varnish coating, where varnish is applied to a specific area of the recording material.

[0011] The present invention has been made in consideration of the above-mentioned problems, and aims to provide an image forming system that can suppress unnecessary cost increases for other optional equipment and suppress the occurrence of image unevenness caused by applying varnish to both sides of the recording material. [Means for solving the problem]

[0012] An image forming system including an image forming apparatus, an inspection apparatus, and a varnish application apparatus, wherein the image forming apparatus: The recording medium has an image forming section that forms an image on a recording material, and a first reversing conveying path that reverses the recording material on which the image has been formed on a first side by the image forming section and conveys the recording material to the image forming section so that an image is formed on a second side opposite to the first side. The inspection device has an inspection means that reads, by a reading means, a recording material on which an image has been formed by the image forming device, and compares the read image data with reference image data to perform an inspection, a first conveying path that conveys the recording material to the reading means, a second conveying path that conveys the recording material to an output tray, a third conveying path that conveys the recording material to the varnish application device, and a fourth conveying path that conveys the recording material to the third conveying path without conveying it to the reading means, and the varnish application device The aforementioned Transported from the inspection equipment The apparatus has a varnish application section that applies varnish to the surface of the recording material, and a second reversal conveyance path that reverses the recording material on which an image has been formed on a first side by the varnish application section and conveys the recording material to the varnish application section so that varnish is applied to a second side of the recording material opposite to the first side. the first conveying path is a conveying path that branches off from the fourth conveying path at a first branching portion and merges with the fourth conveying path via the reading means, the second conveying path is a conveying path that branches off from the fourth conveying path at a second branching portion and leads to the discharge tray, the third conveying path is a conveying path that branches off from the fourth conveying path at the second branching portion and leads to the varnish application device, and if there is no abnormality in the result of the inspection by the inspection means, the inspection device conveys the recording material from the third conveying path to the varnish application device, and if there is an abnormality in the result of the inspection by the inspection means, conveys the recording material from the second conveying path to the discharge tray without conveying it to the varnish application device, and the varnish application device applies varnish to recording materials that are not abnormal in the result of the inspection by the inspection means. It is characterized by: [Effects of the Invention]

[0013] According to the present invention, unnecessary cost increases for various optional devices connected to an electrophotographic image forming apparatus can be suppressed, and the occurrence of image unevenness when performing a varnish application process on both sides of a recording material can be suppressed. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic diagram illustrating an example of a double-sided image forming system according to an embodiment of the present invention; [Figure 2]FIG. 1 is a schematic diagram illustrating an example of an image forming station according to an embodiment of the present invention; [Figure 3] FIG. 2 is an explanatory diagram showing a conveyance path of the recording material P according to the present embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0015] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described in the embodiments are not intended to limit the scope of the present invention.

[0016] The double-sided image forming system according to the present invention will be described below with reference to the drawings. As shown in Figure 1, the double-sided image forming system of this embodiment is connected in sequence to an image forming device 100 that forms double-sided images on a recording material, an inspection device 200 that reads and inspects the images on the recording material, and a varnish application device 300 that can apply varnish to both sides of the recording material.

[0017] <Image forming device> The image forming apparatus 100 of this embodiment is a four-color full-color printer using an electrophotographic process. Specifically, as shown in Figure 1, four image forming stations Pa, Pb, Pc, and Pd are arranged in series in the image feed direction.

[0018] The image forming stations are described below. Figure 2 shows the 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) that replenishing toner to the developing device, and a primary transfer device 145.

[0019] The photosensitive drum 140 that is driven to rotate is charged by a charging device 141, that is, a charging roller, to which a bias voltage is supplied from a high voltage power supply.

[0020] The photosensitive drum 140 is then charged as described above, and an electrostatic latent image is formed on the drum surface by an exposure device 142. The exposure device 142 is composed 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 beam of the scanning light is then deflected by multiple reflecting mirrors and condensed onto the generating line of the photosensitive drum 1 by an fθ lens for exposure, thereby forming an electrostatic latent image on the photosensitive drum 1 according to an image signal.

[0021] The electrostatic latent image formed on the photosensitive drum 140 then faces the developing device 143, where the latent image on the photosensitive drum is sequentially developed with toner in accordance with the potential difference between the high voltage bias applied to the developing sleeve and the surface potential of the photosensitive drum to form a toner image. Here, the developing device 143 is filled with a predetermined amount of two-component developer, which is made by mixing yellow, magenta, cyan, and black non-magnetic toner and magnetic carrier at a predetermined mixing ratio corresponding to the image forming stations Pa, Pb, Pc, and Pd, respectively.

[0022] A toner cartridge, which is a supply device for supplying toner to the developing device, is filled with non-magnetic toner, and the toner is supplied to the developing device in accordance with the amount of non-magnetic toner used within the developing device.

[0023] The control unit controls the driving of the photosensitive drum 140, the polygon in the exposure device 142, the developing sleeve in the developing device 143, and the stirring roller in the developing device. Similarly, the control unit also controls the application of bias to the charging device 141, the developing device 143, and the primary transfer roller 145.

[0024] The toner image formed on the surface of the photosensitive drum 1 by the developing device 143 is then transferred onto the intermediate transfer belt 101 by the transfer device 145. Meanwhile, residual toner remaining on the photosensitive drum 1 after primary transfer is collected by the cleaning device 144.

[0025] The process by which images formed at the image forming stations Pa, Pb, Pc, and Pd are output from the image forming apparatus will be described below with reference to FIG.

[0026] The toner images formed by the image forming stations Pa, Pb, Pc, and Pd and transferred onto the intermediate transfer belt 101 are then secondarily transferred in a secondary transfer device 102 onto a recording material P transported from a recording material cassette 103 through registration rollers 110. The toner image is then fixed by heat and pressure in a fixing unit 104, and the toner image passes through a transport path 111 as a recorded image and is discharged from the image forming apparatus 100. In addition, an intermediate transfer belt cleaning device 105 is constantly in contact with and cleans fogging toner and secondary transfer residual toner adhering to the surface of the intermediate transfer belt 101 downstream in the direction of travel of the intermediate transfer belt from the secondary transfer position onto the recording material P. The image forming stations Pa, Pb, Pc, and Pd and the intermediate transfer belt 101 are examples of image forming units.

[0027] In this embodiment, the image forming apparatus 100 is capable of forming images on both sides of the recording material P. When an image is formed on one first side of the recording material P, the recording material P passes through the fixing unit 104 and then passes through a conveying path 111 and is discharged to the outside of the image forming apparatus 100. On the other hand, when an image is formed on both sides of the recording material, the recording material P passes through the fixing unit 104 and then passes through a conveying path 112, a reversing path 113 as a reversing conveying path, and a double-sided conveying path 114, whereby the front and back sides of the recording material P are reversed. Then, an image is formed on the second side of the recording material P, which is opposite to the first side, through the same process as when an image is formed on the first side.

[0028] <Inspection equipment> 1, the inspection device 200 of this embodiment includes a color sensor 201, which is a first inspection unit, and an image reading unit 202, which is a second inspection unit. The color sensor 201 is a sensor unit that includes, for example, a light source that irradiates white light onto the recording material P, a diffraction grating that separates the reflected light from the recording material P into wavelengths, and multiple image pickup elements (line sensors) that measure the intensity of the reflected light for each wavelength, and measures the color of the image on the recording material P.

[0029] The image reading unit 202 has a front sensor 202a and a back sensor 202b, which are contact image sensors (CIS) that have a CMOS as an imaging element, and is capable of reading image information from both sides of the recording material P.

[0030] The inspection device 200 is provided with a conveying path 203 that conveys the recording material P received from the image forming device 100 to the outside of the inspection device 200, and an inspection path 204 on which a color sensor 201 and an image reading unit 202 are arranged. The inspection path 204 branches off from the conveying path 203, passes below the conveying path 203, and then merges back into the conveying path 203. At the branch point between the conveying path 203 and the inspection path 204, a switching member 205 that switches the conveying path of the recording material P between the conveying path 203 and the inspection path 204 is arranged.

[0031] Moreover, a discharge tray 206 onto which the recording material P is discharged is provided above the inspection device 200, and a discharge conveying path 207 heading toward the discharge tray 206 branches off from the conveying path 203. The discharge path 207 branches off from the conveying path 203 downstream of the junction of the conveying path 203 and the inspection path 204 in terms of the conveying direction of the recording material P on the conveying path 203.

[0032] At the branching point of the conveying path 203 and the discharge path 207, there is disposed a switching member 208 that switches the conveying path of the recording material P between the external discharge path 209 and the discharge path 207. The recording material P guided to the external 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 the recording material P guided to the discharge path 207 by the switching member 208 is discharged onto the discharge tray 206. The switching members 205 and 208 are flap-shaped guide members.

[0033] The inspection device 200 performs an inspection operation to detect whether there are any abnormal images on the recording material P. This inspection operation is performed by a control unit (not shown) comparing reference data used by the image forming apparatus 100 for image formation with information acquired by the color sensor 201 and image reading unit 202 from the recording material P passing through the inspection path 204. The data used by the image forming apparatus 100 for image formation refers to data read from an original by a scanner device or data received from an external computer. An image without image defects refers to, for example, an image with high color reproducibility, where the position and geometric shape of the image relative to the recording material P meet certain conditions, and where abnormalities such as uneven density, color washout, and stains are within acceptable limits.

[0034] When an inspection operation is performed on recording material P on which an image has been formed by the image forming apparatus 100, recording material P that has been determined to have no image defects (passed) is guided to a conveying path 203 and discharged to the outside of the inspection device 200 via an external discharge path 209. On the other hand, recording material P that has been determined to have an image defect (failed) is guided to a discharge path 207 and discharged to a discharge tray 206.

[0035] It should be noted that the color sensor 201 and the image reading unit 202 are both examples of an inspection means, and other inspection means may be used. Furthermore, there are no particular limitations on the items inspected in the inspection operation. For example, the image data read from the recording material P by the image reading unit 202 may be analyzed to check whether there are any errors in the character information printed on the recording material P (for example, the address and name of a mailing).

[0036] <Varnish application equipment> The varnish application device 300 of this embodiment is a typical roll-type varnish coater that applies varnish to the entire surface of a recording material, as shown in Figure 1. The varnish application device 300 is made up of an application roller 301 and backup roller 302 that form an application nip N where varnish is applied to the recording material P, a feed roller 303, a regulating roller 304, a varnish storage unit 305, and a curing device 306. The curing device 306 is made up of a varnish curing unit 307 and a conveying unit 308. The application roller 301, backup roller 302, feed roller 303, regulating roller 304, and storage unit 305 are an example of a varnish application unit.

[0037] Here, each of the rollers 301 to 304 can be rotated by a driving means (not shown). Furthermore, the mutual contact state or separation distance between the feed roller 303 and the regulating roller 304, and between the feed roller 303 and the application roller 301, can be arbitrarily changed by an adjustment mechanism (not shown). Furthermore, the curing unit 307 is a UV irradiation means or a non-contact heating means that can cure or dry the varnish depending on the type of varnish.

[0038] Next, we will explain the varnish application configuration of the varnish application device 300. The varnish storage unit 305 stores the varnish supplied by the feed roller 303. The storage unit 305 is a case that opens upward and stores the varnish inside. The feed roller 303 is arranged so that part of its surface is immersed in the varnish stored inside the case of this storage unit 305.

[0039] The varnish liquid is drawn up from the reservoir 305 by the rotation of the feed roller 303 , passes through the opposing portion of the feed roller 303 and the regulating roller 304 , and then moves to the surface of the application roller 301 by the contact between the feed roller 303 and the application roller 301 .

[0040] Here, the amount of varnish applied to the application roller 301 can be adjusted by adjusting at least one of the rotation speed of the feed roller 303, the distance between the feed roller 303 and the regulating roller 304, and the contact pressure between the feed roller 303 and the application roller 301.

[0041] By using the above-described application configuration and a mechanism for adjusting the amount of varnish applied, it is possible to adjust the thickness of the varnish applied to the recording material P in the application nip portion N.

[0042] In this embodiment, the varnishing device 300 is capable of applying varnish to both sides of a recording material. When applying varnish to the first side of a recording material, the recording material P passes through the curing device 306 and is discharged outside the varnishing device 300 via the external discharge path 311. On the other hand, when applying varnish to both sides of a recording material, the recording material P is turned over through the conveying path 312, the reversing path 313, and the double-sided conveying path 314. The reversed recording material P then undergoes the same process as when applying varnish to the first side, and varnish is applied to the second side opposite the first side. Then, the recording material P with varnish applied to both sides passes through the curing device 306 again and is discharged outside the varnishing device 300 via the external discharge path 311.

[0043] <Transport path of recording material P> Next, the conveying path when the varnish coating process is performed on both sides of the recording material P in the configuration of this embodiment will be described with reference to FIG.

[0044] When a job for applying varnish to both sides of a recording material P is started, the recording material P in the recording material cassette 103 is transported 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 transported from the registration rollers 110 to the secondary transfer device 102, and an unfixed toner image is formed on one surface (first side) of the recording material P.

[0045] Thereafter, the unfixed toner image formed on the first side of the recording material P is fixed in a 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 switched back and conveyed toward a double-sided conveying path 114, whereby the first side of the recording material P on which the image is formed is swapped with the side on which no image is formed (the second side).

[0046] The recording material P, whose first and second sides have been swapped, passes through a double-sided conveying path 114 and is conveyed toward registration rollers 110, where it undergoes the same process as the image formed on the first side, and a toner image is formed on the second side of the recording material P by a secondary transfer device 102. Thereafter, the toner image formed on the second side of the recording material P is fixed by a fixing unit 104. Then, the recording material P, whose both sides have the toner images fixed, passes through a discharge conveying path 111 and is discharged outside the image forming apparatus 100.

[0047] Next, when the inspection device 200 receives the recording material P discharged from the image forming device 100, it conveys the recording material P to a conveying path 203 and an inspection path 204, reads the images on the first and second sides of the recording material P, and inspects for image defects. If there are no image defects on the recording material P, it returns to the conveying path 203 and passes through an external discharge path 209 and is discharged outside the inspection device 200.

[0048] Next, the varnish application device 300 receives the recording material P discharged from the inspection device 200, transports it through the registration rollers 310 to the application nip N, and applies varnish to the second side of the recording material P. Thereafter, the recording material P is cured by the curing device 306 to harden the applied varnish, and is then transported to the conveying path 312 and sent to the reversing path 313.

[0049] The recording material P sent to the reversing path 313 is switched back and conveyed toward the double-sided conveying path 314, whereby the second side of the recording material P, which is varnished, is swapped with the first side, which is not varnished. The recording material P, whose second and first sides have been swapped, passes through the double-sided conveying path 314 and is conveyed toward the registration rollers 310, where varnish is applied to the first side of the recording material P at the application nip N. The recording material P then has the applied varnish hardened in the hardening device 306, and is then discharged outside the varnish application device 300 via the external discharge path 311.

[0050] As described above, in the configuration of this embodiment, it is possible to form images on and apply varnish to both sides of the recording material P by reversing the recording material P in each of the image forming apparatus 100 and the varnish application apparatus 300. Therefore, the inspection apparatus 200, which is located between the image forming apparatus 100 and the varnish application apparatus 300, does not require a transport path to return the recording material P from the varnish application apparatus 300 to the image forming apparatus 100, making it possible to avoid unnecessary increases in the cost of the inspection apparatus.

[0051] In the configuration of this embodiment, the inspection device 200 is exemplified as an optional device placed between the image forming apparatus 100 and the varnish application device 300, but this is not limited to this. In other words, any optional device placed between the image forming apparatus and the varnish application device can be applied, including cases where multiple types of optional devices are connected at the same time. For example, good examples include an inserter that inserts a cover page when outputting a booklet, or a cleaning device that removes foreign matter adhering to the surface of the recording material before the varnish application process.

[0052] The recording material P, which has been varnished on both sides, is then transported again along transport path 312 and sent to reversal path 313. The recording material P may then be switched back toward discharge path 311, allowing the first and second sides of the recording material P to be reversed before being discharged from the varnishing device 300. In this case, the orientation of the recording material P when it is discharged from the varnishing device 300 (first side up or second side up) can be appropriately selected depending on the operation of optional devices connected further downstream of the varnishing device 300 in the recording material transport direction. Optional devices connected further downstream of the varnishing device 300 include a binder that binds the recording material, a folder that folds the recording material, and a finisher that staples and sorts the recording material. Optional devices connected further downstream of the varnishing device 300 include a puncher that punches holes in the recording material and a trimmer that cuts the recording material.

[0053] The means for applying the varnish liquid to the recording material P is not limited to a roll type using the application roller 301 and backup roller 302, but may also be a line head that ejects the varnish using an inkjet method. When a line head is used, spot coating is possible, in which varnish is selectively applied to any position on the recording material P.

[0054] In electrophotographic printers, toner images are electrostatically transferred to recording materials, resulting in differences in electrical resistance between varnished and unvarnished areas of the recording material. This can lead to image unevenness when transferring an image to the backside of a spot-coated recording material. However, according to the present invention, after forming an image on both sides of the recording material, a varnish application device applies varnish to both sides of the recording material, thereby suppressing image unevenness caused by applying varnish to both sides. [Explanation of symbols]

[0055] 100 Image forming device 101 Intermediate transfer belt 102 Secondary transfer device 103 Recording material cassette 104 Fixing section 105 Intermediate transfer belt cleaning device 110 Registration roller 111 Aircraft discharge pass 112 Transport path 113 Reverse Pass 114 Double-sided transport path 200 Inspection equipment 201 Color Sensor 202 Image reading unit 203 Transport Path 204 Inspection Pass 205 Switching member 206 Output tray 207 Emission Pass 208 Switching member 209 Aircraft Discharge Pass 300 Varnish application device 301 Application roller 302 Backup roller 303 Feed roller 304 Regulating roller 305 Storage Unit 306 Curing equipment 307 Curing means 308 Conveyor 310 Registration roller 311 Aircraft discharge pass 312 Transport Path 313 Reverse Pass 314 Double-sided transport path Pa, Pb, Pc, Pd imaging station N Application nip

Claims

1. An image forming system comprising an image forming apparatus, an inspection apparatus, and a varnish application apparatus, the image forming apparatus includes an image forming unit that forms an image on a recording material, and a first reversing conveying path that reverses the recording material on which the image has been formed on a first side by the image forming unit and conveys the recording material to the image forming unit so that an image is formed on a second side opposite to the first side, The inspection device has an inspection means that reads a recording material on which an image has been formed by the image forming device using a reading means and compares the read image data with reference image data to perform an inspection, a first conveying path that conveys the recording material to the reading means, a second conveying path that conveys the recording material to an output tray, a third conveying path that conveys the recording material to the varnish application device, and a fourth conveying path that conveys the recording material to the third conveying path without conveying it to the reading means, The varnish application device has a varnish application section that applies varnish to the surface of the recording material transported from the inspection device, and a second reversal transport path that reverses the recording material on which an image has been formed on a first side by the varnish application section and transports the recording material to the varnish application section so that varnish is applied to a second side of the recording material opposite to the first side, the first conveying path is a conveying path that branches off from the fourth conveying path at a first branching portion and merges with the fourth conveying path via the reading means, the second transport path is a transport path that branches off from the fourth transport path at a second branching portion and leads to the discharge tray, the third conveying path is a conveying path that branches off from the fourth conveying path at the second branching portion and is connected to the varnish applying device, When the inspection by the inspection means shows no abnormality, the inspection device conveys the recording material from the third conveying path to the varnish application device, and when the inspection by the inspection means shows an abnormality, the inspection device conveys the recording material from the second conveying path to the discharge tray without conveying it to the varnish application device, The image forming system is characterized in that the varnish application device applies varnish to recording materials that are found to have no abnormalities in the results of inspection by the inspection means.

2. the varnish application unit includes an application roller that applies varnish to the recording material, and a backup roller that transports the recording material together with the application roller; 2. The image forming system according to claim 1.

3. the varnish application unit has a line head that injects varnish onto the recording material; 2. The image forming system according to claim 1.

4. the varnish application device has a curing unit that hardens the varnish applied to the recording material by the varnish application unit; 4. The image forming system according to claim 1, wherein the image forming apparatus is a printer.

Images