Patent ID: 12216423

DESCRIPTION OF THE EMBODIMENTS

First Embodiment

First, an image forming system1X of this embodiment will be described usingFIG.1. The image forming system1X shown inFIG.1includes an image forming apparatus100for forming a toner image on a recording material S, a varnish applying apparatus200(referred to as a varnish coater) for forming a varnish image on the recording material S, and an image inspection apparatus400for inspecting the toner image and the varnish image which are formed on the recording material S. The varnish coater200and the image inspection apparatus400are post-step units each retrofittable to the image forming apparatus100for expanding function. The image forming apparatus100and the varnish coater200, and the varnish coater200and the image inspection apparatus400are, respectively, connected to each other so as to be capable of delivering the recording material S therebetween. The image forming apparatus100, the varnish coater200, and the image inspection apparatus400are connected to each other by data input/output interfaces (not shown) so as to be capable of sending and receiving control signals and data therebetween. Incidentally, the image forming apparatus100, the varnish coater200, and the image inspection apparatus400are not required to be separate members, but may also be integrally constituted with each other.

The recording material S on which the toner image is formed by the image forming apparatus100is conveyed to the varnish coater200for the purpose of improving glossiness, water resistance, friction resistance, and the like of the toner image, so that the varnish image is capable of being formed superposedly on the toner image which is the background image by the varnish coater200. Thereafter, the recording material S on which the varnish image is formed by the varnish coater200is conveyed toward the image inspection apparatus400, and is subjected to inspection of positional deviation in the toner image and the varnish image by the image inspection apparatus400. Incidentally, as the recording material S, it is possible to cite sheet materials such as plain paper, thick paper, rough paper, uneven paper, coated paper, and the like.

<Image Forming Apparatus>

The image forming apparatus100will be described. The image forming apparatus100is an electrophotographic full-color printer of a tandem type. The image forming apparatus100forms the toner image on the recording material S on the basis of background image master data (described later). The image forming apparatus100includes image forming portions Pa, Pb, Pc, and Pd for forming images of yellow, magenta, cyan, and black, respectively.

A feeding (conveying) process of the recording material S in the image forming apparatus100will be described. The recording materials S are accommodated in a cassette10in a stacked form, and each recording material S is sent from the cassette10in synchronism with an image forming timing by a supplying roller13. The recording material S sent by the supplying roller13is conveyed toward a registration roller pair12provided in the course of a feeding (conveying) path114. Then, the recording material S is subjected to oblique movement correction or timing correction by the registration roller pair12, and thereafter, is sent to a secondary transfer portion T2. The secondary transfer portion T2is a transfer nip formed by an inner secondary transfer roller14and an outer secondary transfer roller11, and the toner image is transferred onto the recording material S in response to application of a secondary transfer voltage to the outer secondary transfer roller11.

As regards the recording material S feeding process to the above-described secondary transfer portion T2, an image forming process of the image sent to the secondary transfer portion T2at a similar timing will be described. First, although the image forming portions will be described, the respective color image forming portions Pa, Pb, Pc and Pd are constituted substantially similar to each other except that colors of toners used in developing devices1a,1b,1cand1dare yellow (Y), magenta (M), cyan (C), and black (K), respectively, which are different from each other. Therefore, in the following, as a representative, the image forming portion Pd for black will be described, and other image forming portions Pa, Pb and Pc will be omitted from description.

The image forming portion Pd is principally constituted by the developing device1d, a charging device2d, a photosensitive drum3d, a photosensitive drum cleaner4d, an exposure device5d, and the like. A surface of a rotating photosensitive drum3dis electrically charged uniformly in advance by the charging device2d, and thereafter, an electrostatic latent image is formed by the exposure device5ddriven on the basis of a signal of image information. Then, the electrostatic latent image formed on the photosensitive drum3dis developed into a toner image with use of a developer by the developing device1d. Then, the toner image formed on the photosensitive drum3dis primary-transferred onto an intermediary transfer belt80in response to application of a primary transfer voltage to a primary transfer roller6ddisposed opposed to the image forming portion Pd while sandwiching the intermediary transfer belt80therebetween. Primary transfer residual toner slightly remaining on the photosensitive drum3dis collected by the photosensitive drum cleaner4d.

The intermediary transfer belt80is stretched by the inner secondary transfer roller14, and stretching rollers15and16, and is driven in an arrow R2direction. In the case of this embodiment, the stretching roller16also functions as a driving roller for driving the intermediary transfer belt80. The respective color image forming processes processed in parallel by the image forming portions Pa to Pd are carried out at timings each when the associated toner image is superposedly transferred onto the upstream toner image primarily transferred onto the intermediary transfer belt80. As a result, finally, a full-color toner image is formed on the intermediary transfer belt80and is conveyed to the secondary transfer portion T2. Incidentally, secondary transfer residual toner after passing through the secondary transfer portion T2is removed from the intermediary transfer belt80by a transfer cleaner22.

In the above, by the above-described feeding process and the above-described image forming process, in the secondary transfer portion T2, the timing of the recording material S and the timing of the full-color toner image coincide with each other, so that secondary transfer is carried out. Thereafter, the recording material S is conveyed to a fixing device50, in which heat and pressure are applied to the recording material S, so that the toner image is fixed on the recording material S. The fixing device50nips and feeds the recording material S on which the toner image is formed, and applies heat and pressure to the fed recording material S, so that the fixing device50fixes the toner image on the recording material S. That is, the toner of the toner image formed on the recording material S is melted and mixed, and is fixed as the full-color image on the recording material S.

The image forming apparatus100is capable of printing images on double (both) sides of the recording material S. In an operation in one-side printing mode, the recording material S on which the toner image is fixed on one (surface) side by the fixing device50is conveyed to the varnish coater200. In an operation in double-side printing mode, the recording material S on which the toner image is fixed on one (surface) side by the fixing device50is conveyed to a double-side feeding portion90. In the double-side feeding portion90, the recording material S is reversed while being fed, so that a front surface (first surface) and a back surface (second surface) of the recording material S are switched. The reversed recording material S is re-fed toward the registration roller pair12through the double-side feeding portion90. Then, the recording material S is fed by the registration roller pair12toward the secondary transfer portion T2in a state in which the back surface side (second surface side) where the image is not printed is directed toward the intermediary transfer belt80side. In the secondary transfer portion T2, the toner images for the full-color image formed on the intermediary transfer belt80are secondary-transferred collectively onto the back surface side of the recording material S. Thereafter, the toner images are fixed on the recording material S by the fixing device50, and then the recording material S on which the toner images are fixed is conveyed to the varnish coater200.

<Developer>

In this embodiment, a two-component developer containing the toner and a carrier is used. The toner contains a binder resin, a colorant, and a parting agent (wax). As the binder resin, a known binder resin can be used. For example, it is possible to use resin materials such as a vinyl copolymer represented by a styrene-(meth)acrylic copolymer, a polyester resin, a hybrid resin obtained by chemically bonding a vinyl copolymer unit and a polyester unit to each other, an epoxy resin, a styrene-butadiene copolymer, and the like. As the colorant, it is possible to use known colorants for yellow (Y), magenta (M), cyan (C), and black (K), respectively.

As the parting agent, for example, it is possible to cite aliphatic hydrocarbon waxes such as low-molecular weight polyethylene, low-molecular weight olefin copolymer wax, microcrystalline wax, Fischer-Tropsch wax, and paraffin wax; oxide of the aliphatic hydrocarbon wax such as oxidized polyethylene wax; their block copolymers; waxes principally containing fatty acid esters such as carnauba wax and montanic acid ester wax; ester wax which is synthetic reaction product between higher aliphatic acid, such as behenyl behenate or behenyl stearate, and higher alcohol; fatty acid esters a part or all of which is deoxidized, such as deoxidized carnauba wax; and the like.

<Varnish Coater>

Next, the varnish coater200will be described usingFIGS.1and2. The varnish coater200is an apparatus for forming the varnish image on the recording material S on the basis of varnish image master data (described later). In the case where the varnish coater200is of an ink jet type, separately from the toner images, varnish images such as characters, diagrams, graphics, and the like, which are desired by users, are formed by ejecting varnish in the form of droplets toward the recording material S and by causing the varnish to be deposited on the recording material S. Incidentally, as the varnish, various varnishes such as an aqueous varnish, an oil varnish, and a UV varnish may be used, and in the following, the varnish coater200for forming a varnish image with the UV varnish, such as an ultraviolet-curable type, solidified by UV irradiation will be described as an example.

The varnish coater200includes a sheet feeding portion241, a position detecting portion245, a varnish ejecting portion246, and a varnish solidifying portion247. The sheet feeding portion241feeds the recording material S while attracting the recording material S to a belt feeding surface by an air sucking device (not shown) through holes formed in a feeding belt. Along a sheet feeding passage of this sheet feeding portion241, in an order from an upstream side toward a downstream side of a feeding direction (arrow X direction) of the recording material S, the position detecting portion245, the varnish ejecting portion246, and the varnish solidifying portion247are disposed. The position detecting portion245is a detecting portion using a CCD, or the like, for example, and with respect to the recording material S fed while being sucked on the belt feeding surface, the position detecting portion245is capable of detecting each of a position of a leading end of the recording material S with respect to the feeding direction, and a position of each of opposite end portions with respect to a widthwise direction crossing the feeding direction of the recording material S.

The varnish ejecting portion246forms the varnish image on the recording material S by ejecting the UV varnish onto one surface (side) of the recording material S fed by the sheet feeding portion241. The varnish ejecting portion246includes a plurality of print heads (not shown). The print heads are, for example, heads of a line type, in which a plurality of ejection ports (not shown) are arranged and disposed in the widthwise direction crossing the feeding direction of the recording material S so as to extend over a range covering a maximum width of the recording material S on which the image is capable of being formed by the varnish coater200. A varnish ejecting method of the print heads may employ a type using heat generating elements, a type using piezo electric elements, a type using electrostatic elements, a type using MEMS elements, and the like. Although illustration is omitted, the UV varnish is supplied from a tank to the associated one of the print heads through a tube.

A film thickness of the varnish image is influenced by an application amount per unit area of the UV varnish onto the recording material S. The varnish application amount can be changed by adjusting a varnish ejecting amount from the print heads. For example, in the case of the type using the piezoelectric elements, as shown inFIG.2, the varnish ejection amount varies depending on adjustment of a control voltage, and the film thickness of the varnish image is adjusted depending on an increase and a decrease in varnish ejection amount per unit area. In the case of this embodiment, the film thickness of the varnish image is adjusted in a range of, for example, “5-100 μm”, preferably “10-70 μm”.

Further, a resolution of the varnish image capable of being formed by the varnish coater200is, for example, “600 dpi”, and in that case, the line width of the varnish image is adjusted in a “600 dpi” unit. Incidentally, the above-described range of the film thickness of the varnish image, the resolution of the varnish image, and an adjusting range of the line width of the varnish image may be appropriately changed depending on the varnish ejecting method of the print heads, a kind of the varnish, and the like.

Returning toFIG.1, the recording material S on which the varnish image is formed on one surface thereof by the varnish ejecting portion246is sent by the sheet feeding portion241to the varnish solidifying portion247positioned downstream of the varnish ejecting portion246with respect to the feeding direction, and then the UV varnish on the recording material S is solidified by the varnish solidifying portion247. The varnish solidifying portion247includes a UV lamp, and the UV lamp irradiates the UV varnish with UV radiation (UV rays) of a wavelength corresponding to the UV varnish. The UV lamp is disposed in an almost entire region of the recording material S with respect to the widthwise direction so as to be capable of emitting the UV light (UV radiation), and is turned on only during passing of the recording material S. As described above, the varnish image is capable of being overprinted superposedly on the toner image formed on the recording material S. Thereafter, the recording material S is conveyed to the image inspection apparatus400.

<Image Inspection Apparatus>

Next, the image inspection apparatus400will be described. The image inspection apparatus400is an apparatus for inspecting the toner image and the varnish image which are formed on the recording material S. As shown inFIG.1, the image inspection apparatus400includes a feeding roller401, an image reading portion402, a carrying-out roller403, an image analyzing portion404, and a controller (not shown) for controlling drive of these portions. These portions are driven on the basis of information from the main controller101included in the image forming apparatus100, so that the image inspection apparatus400is capable of inspecting the toner image and the varnish image which are formed on the recording material S.

The feeding roller401feeds the recording material S, discharged from the varnish coater200, into the image inspection apparatus400. The image reading portion402reads, as an inspection image, the toner image and the varnish image which are formed on the recording material S, and includes a light irradiation device402a, a diffused light detecting device402b, and a regular reflection light detecting device402c. The light irradiation device402airradiates the surface of the recording material S, fed by the feeding roller401, with detection light such a white light over the widthwise direction crossing the feeding direction.

The diffused light detecting device402bdetects diffused light diffused and reflected from the surface of the recording material S in response to irradiation of the recording material surface with detection light from the light irradiation device402a. For example, as the diffused light detecting device402b, a line sensor is used. Then, the detected diffused light is converted into an electric signal and is sent as diffused light image data [Dh1] to the image analyzing portion404. The regular reflection light detecting device402cdetects regular reflection light regularly reflected from the surface of the recording material S in response to irradiation of the recording material surface with the detection light from the light irradiation device402a. For example, as the regular reflection light detecting device402c, a line sensor is used. Then, the detected regular reflection light is converted into an electric signal and is sent as regular reflection light image data [Dh2] to the image analyzing portion404. Incidentally, the image inspection apparatus400may only be required to be provided with at least one of the diffused light detecting device402band the regular reflection light detecting device402c, but in this embodiment, the case where both the devices402band402care provided was cited as an example.

The carrying-out roller403discharges the recording material S, fed by the feeding roller401and passed through the image reading portion402, to an outside of the image inspection apparatus400. The recording material S is capable of being discharged by the carrying-out roller403onto either one of an OK tray400aor an NG tray400bon the basis of a result of positional deviation by the image analyzing portion404(described later). For example, a recording material S on which positional deviation does not occur in the toner image and the varnish image is discharged on the OK tray as a second tray, and a recording material S on which positional deviation does not occur in the toner image and the varnish image is discharged on the NG tray400bas a first tray. Each of the OK tray400aand the NG tray400bis capable of stacking a large number of sheets of the recording materials S.

Next, a control constitution of an image forming control system in the image forming system1X will be described usingFIG.3while making reference toFIG.1. In this embodiment, an example in which the image forming apparatus100unitarily manages and controls operation instructions to the varnish coater200and the image inspection apparatus400(image inspecting device) will be described. Incidentally, to a main controller101, in addition to the devices (portions) illustrated inFIG.3, various devices may be connected, but are not the main object of the present invention herein, and therefore, will be omitted from illustration and description.

In the image forming system1X of this embodiment, to the main controller101, the operating portion110, the varnish coater200, and the image inspection apparatus400are connected so as to be capable of communicating operation instructions and various data. Thus, while the main controller101operates the image forming apparatus100, the main controller101is capable of controlling entirety of the image forming system1X by sending the operation instructions and the various data to the varnish coater200and the image inspection apparatus400.

The main controller101includes a calculating portion103capable of calculating positional deviation of the toner image and the varnish image which are formed on the recording material S. Calculation of the positional deviation of the toner image and the varnish image will be described later. Further, the main controller101includes a CPU (central processing unit), and a memory102such as a ROM (read only memory), or a RAM (random access memory). In the memory102as a storing portion, various programs such as “recording material output processing” (seeFIG.14) and various data such as “a correction table” (see a table 1), which are described later, are stored. The CPU is capable of executing the various programs by using the various data stored in the memory102. In the RAM, various data such as image master data received, for example, from an external device1000are stored. Further, the RAM is capable of temporarily storing a calculation (computation) processing result or the like with execution of the various programs. The image master data includes background image master data [Dg] as first image data and varnish image master data [Dv] as second image data.

The background image master data [Dg] and the varnish image master data [Dv] are data formed with, for example, graphic design software (“Adobe Illustrator (trademark)”, and are sent from the external device1000via a network interface. The background image master data [Dg] is data on the toner image capable of being formed by the image forming apparatus100, and the varnish image master data [Dv] is data on the varnish image capable of being formed by the varnish coater200.

The main controller101is capable of executing processing such that the background image master data [Dg] and the varnish image master data [Dv] are changed to data capable of being processed by the image forming apparatus100and the varnish coater200, respectively. Further, the main controller101is capable of executing various pieces of processing, such as toner image formation by the image forming apparatus100, varnish image formation by the varnish coater200, setting necessary for image inspection by the image inspection apparatus400, and the like.

The background image master data [Dg] and the varnish image master data [Dv] includes information on relative positional relationship as forming positions of the toner image and the varnish image which are formed on the recording material S. Herein, the relative positional relationship is, for example, image information such that resolutions are the same value and is information such that a pixel of the background image master data [Dg] and a pixel of the varnish image master data [Dv] are in a one-to-one correspondence. This relative positional relationship is not only the one-to-one correspondence as image information, but also may be image information such that resolutions are different from each other and that includes margin information (for example, distance information from four sides of the recording material S) on an image forming position on the recording material S. In this case, the main controller101converts one of the background image master data [Dg] and the varnish image master data [Dv] into the resolution on the basis of a ratio of the resolutions of the background image master data [Dg] and the varnish image master data [Dv] and the margin information and carries out positional alignment on the basis of the margin information. By this, the pixel of the background image master data [Dg] and the pixel of the varnish image master data [Dv] are associated with each other in a one-to-one correspondence.

Further, the varnish image master data [Dv] includes information on the varnish in addition to the forming position of the varnish image. As the information on the varnish, it is possible to cite, for example, a kind and glossiness of the varnish, values of light intensity of diffused light diffusedly reflected in the case where the varnish is irradiated with the white light and light intensity of regular reflection light regularly reflected in the case where the varnish is irradiated with the white light, and the like. Incidentally, the varnish image master data [Dv] sent from the external device1000is not required to include the above-described information on the varnish, and in that case, the information on the varnish may only be required to be stored in advance in the varnish coater200.

The image forming system1X includes the operating portion110including, for example, a liquid crystal display portion111, and the operating portion110is connected to the main controller101. The operating portion110is, for example, a touch panel. On the liquid crystal display portion111, various screens presenting the various programs and various data or the like can be displayed by the operating portion110. Further, the operating portion110receives input of a start of the various programs and input of the various data, and the like, depending on a screen touch operation by a user. Incidentally, on the touch panel, a screen including various buttons, switches, and the like as software keys may be displayed.

The user is capable of inputting a start of an image forming job from the operating portion110. In the case where the start of the image forming job is inputted, the main controller101executes the “recording material output processing” (seeFIG.5) stored in the memory102. With this execution, the image forming apparatus100and the varnish coater200are operated, so that the toner image and the varnish image are formed on the recording material S. Further, the image inspection apparatus400is operated, so that image inspection of the toner image and the varnish image which are formed on the recording material S is performed.

The image inspection apparatus400includes the image analyzing portion404constituted by the CPU, the ROM, the RAM, and the like which are not shown. The image analyzing portion404acquires detection background image data [Dpg] and detection varnish image data [Dpv] diffused light image data [Dh1] detected by the diffused light detecting device402band regular reflection light image data [Dh2] detected by the regular reflection light detecting device402c. The image analyzing portion404stores, as a reflected light table, values of light intensity of the diffused light and the regular reflection light for each of a kind of the varnish, a kind of the background image, and a kind of the recording material. The image analyzing portion404processes the diffused light image data [Dh1] and regular reflection light image data [Dh2] by making reference to a reflected light table to acquire the detection background image data [Dpg] and the detection varnish image data [Dpv]. Incidentally, in this embodiment, data by which the detected toner image is associated with a coordinate of an image forming region in the recording material S is referred to as the detection background image data [Dpg], and data by which the detected varnish image is associated with a coordinate of the image forming region in the recording material S is referred to as the detection varnish image data [Dpv].

Each of the detection background image data [Dpg] and the detection varnish image data [Dpv] is data by which the toner image (or the varnish image) is associated with the coordinate of the image forming region in the recording material S. For that reason, in the case where the resolution of the toner image and the resolution of the varnish image coincide with each other, a pixel position of the detection background image data [Dpg] and a pixel position of the detection varnish image data [Dpv] can be associated with each other. On the other hand, in the case where the resolution of the toner image and the resolution of the varnish image are different from each other, on the basis of a ratio between the detection background image data [Dpg] and the detection varnish image data [Dpv] and coordinate information on the image forming positions on the recording material S, one of the background image master data [Dg] and the varnish image master data [Dv] is converted into the resolution and then positioned alignment is carried out. By doing so, the pixel position of the detection background image data [Dpg] and the pixel position of the detection varnish image data are associated with each other.

<Movement Deviation>

In some cases, a situation such that a toner image caused “movement deviation” is formed on the recording material S is formed, for example, when the electrostatic latent image is formed on the photosensitive drum3d, when the toner image is primary-transferred from the photosensitive drum3donto the intermediary transfer belt80, or when the toner image is secondary-transferred from the intermediary transfer belt80onto the recording material S. The toner image caused the “movement deviation” is detected the detection background image data [Dpg] having a parallel movement component (translation component) shifted relative to the background image master data [Dg] in the feeding direction of the recording material S and a widthwise direction crossing the feeding direction.

On the other hand, in the varnish coater200, for example, when the recording material S is fed in the sheet feeding portion241, a situation that the varnish image caused the “movement deviation” is formed on the recording material S is formed in some cases. The varnish image caused the “movement deviation” is detected as the detection varnish image data [Dpv] having a parallel movement component relative to the varnish image master data [Dv].

<Magnification Deviation>

In the case where the recording material S during feeding causes slip in the secondary transfer portion12or is in a situation that contracts with heating by the fixing device50, “magnification deviation” can occur in the toner image on the recording material S. This is because the toner image formed on the recording material S is capable of contracting with contraction of the recording material S itself by a decrease in water content of the recording material S due to heating by the fixing device50. Thus, when on the toner image formed on the recording material S, the varnish image is formed by the varnish coater200while being in a state in which magnification deviation occurs relative to the background image master data [Dg], the “magnification deviation” such that the toner image and the varnish image shift capable of being caused to occur.

<Recording Material Output Processing>

Next, “recording material output processing” in the first embodiment will be described usingFIGS.4to10while making reference toFIG.3. The “recording material output processing” is started by the main controller101in synchronism with, for example, input of a start of an image forming job and is repeated until an end of the image forming job.

As shown inFIG.4, every time when a single image forming job is started, the main controller101performs initialization such that an initial value “1” is set for a counter “N” for holding the number of sheets subjected to image formation during execution of the image forming job (S1). In the case of this embodiment, as described later, the number of sheets on which positional deviation does not occur between the toner image and the varnish image is counted and is held in the counter “N”. Then, the main controller101acquires the background image master data [Dg] and the varnish image master data [Dv], and causes the image forming apparatus100to form the toner image on N-th recording material S and causes the varnish coater200to form the varnish image on the N-th recording material S (S2).

Incidentally, here, in the case of initial (first) image formation of the image on the N-th recording material S, the toner image and the varnish image are formed without correcting the background image master data [Dg] and the varnish image master data [Dv]. On the other hand, in the case of second image formation and later of the image on the N-th recording material S, the background image master data [Dg] and the varnish image master data [Dv] are corrected, and the toner image and the varnish image are formed.

The main controller101acquires the detection background image data [Dpg] and the detection varnish image data [Dpv] from the image inspection apparatus400(S3). From coordinate information on position reference point based on the acquired detection background image data [Dpg] and the acquired detection varnish image data [Dpv], the main controller101acquires each of a movement deviation amount and a magnification deviation amount, as a positional deviation amount of the toner image and the varnish image which are actually formed on the N-th recording material S.

<Positional Deviation Amount of Toner Image and Varnish Image>

A manner of acquiring the positional deviation amount of the toner image and the varnish image which are formed on the recording material S will be described. The main controller101sets a “position reference point” used for detecting positional deviation of the image in the background image master data [Dg] and the varnish image master data [Dv].

Setting of the position reference point is made, for example, by designation of an arbitrary toner image and an arbitrary varnish image from the operating portion110by the user. In an example shown in part (a) ofFIG.5, it is assumed that the toner image and the varnish image which have the same size and the same shape (rectangular shape) defined in the background image master data [Dg] and the varnish image master data [Dv] and which are formed superposedly in an entire region. Then, as shown in part (a) ofFIG.5, a rectangular region which is the designated toner image and the designated varnish image is specified, so that four points of points P1, P2, P3and P4which are apexes of this rectangular region are set as “position reference points”.

Further, also, in the detection background image data [Dpg] and the detection varnish image data [Dpv] which are a detection result of the image inspection apparatus400, “position reference points”, corresponding to the points P1, P2, P3, and P4which are the “position reference points” on each of the image master data shown in part (a) ofFIG.5are set. Specifically, as shown in part (b) ofFIG.5, for example, the position reference points in the detection background image data [Dpg] are set at points Pg1, Pg2, Pg3, and Pg4, and the position reference points in the detection varnish image data [Dpv] are set at points Pv1, Pv2, Pv3, and Pv4. X-coordinates and Y-coordinates of these position reference points are as shown in part (b) ofFIG.5. Setting of the position reference points on each of the detection image data corresponding to the associated image master data is made on the basis of a predetermined algorism such as execution of corner detection in a designated region on the detection image data or execution of template matching between the image master data and the detection image data.

Another example of the setting of the position reference points will be described. For example, as shown in part (a) ofFIG.6, it is assumed that a varnish image formed a character information of “” and a toner image formed as an image other than the character information of “” which are defined as the background image master data [Dg] and the varnish image master data [Dv] are designated. That is, in the background image master data [Dg], the toner image which is the image other than the character information (i.e., the image excluding a white-blanking portion) shown in part (b) ofFIG.6is defined, and in the varnish image master data [Dv], the varnish image of the character information shown in part (c) ofFIG.6is defined.

In this case, depending on designation of the character information of “” through the operating portion110or the external device1000, the four apexes (P1, P2, P3, and P4) in a rectangular region specified so as to surround the designated character information are set at the “position reference points”. Also, in the detection background image data [Dpg] and the detection varnish image data [Dpv], “position reference points” corresponding to the points P1, P2, P3and P4which are the “position reference points” on each information shown in part (a) ofFIG.6are set.

After setting of the above-described “position reference points”, the main controller101causes the calculating portion103to calculate positional deviation amounts between the toner image and the varnish image by comparing coordinates of the above-described position reference points with each other in the detection background image data [Dpg] and the detection varnish image data [Dpv].

A movement deviation amount QX of X-component of the varnish image relative to the toner image and a movement deviation amount QY of Y-component of the varnish image relative to the toner image are acquired by calculating the X-component and the Y-component of a difference of barycentric coordinates of the rectangular region constituting the position reference points of each of the detection varnish image data [Dpv] relative to the detection background image data [Dpg]. As shown in part (a) ofFIG.7, the movement deviation amounts QX and QY as third movement deviation are calculated by the following formulas (1) and (2), respectively.
QX={(xv1+xv2+xv3+xv4)/4}−{(xg1+xg2+xg3+xg4)/4}  formula (1)
QY={(yv1+yv2+yv3+yv4)/4}−{(yg1+yg2+yg3+yg4)/4}  formula (2)

On the other hand, the magnification deviation amount is a ratio of a length of a side on the detection background image data [Dpg] to a length of an associated side on the detection varnish image data [Dpv] as to two sides of the rectangular region constituting the four position reference points. As shown in part (a) ofFIG.8, a magnification deviation amount RX in X-direction and a magnification deviation amount RY in Y-direction are calculated by the following formulas (3) and (4), respectively.
RX=(xg4−xg1)/(xv4−xv1)  formula (3)
RY=(yg2−yg1)/(yv2−yv1)  formula (4)
<Positional Deviation Amount Between Image Master Data and Detection Image Data>

Returning toFIG.4, the main controller101causes the calculating portion103to calculate a positional deviation amount between the image master data and the detection image data on the N-th recording material S (S5). A calculating method of the positional deviation amount between the image master data and the detection image data will be described.

A movement deviation amount SgX of X-component between the background image master data [Dg] and the detection background image data and a movement deviation amount SgY of Y-component between the background image master data [Dg] and the detection background image data are calculated by the following formulas (5) and (6), respectively. The movement deviation amounts SgX and SgY as first movement deviation correspond to a movement difference between center of gravity of the position reference points (P1, P2, P3, and P4) on the background image master data [Dg] and center of gravity of position reference points (Pg1, Pg2, Pg3, and Pg4) on the detection background image data.
SgX={(xg1+xg2+xg3+xg4)/4)}−{(x1+x2+x3+x4)/4}  formula (5)
SgY={(yg1+yg2+yg3+yg4)/4}−{(y1+y2+y3+y4)/4}  formula (6)

Further, a movement deviation amount SgX of X-component between the varnish image master data [Dv] and the detection varnish image data and a movement deviation amount SvY of Y-component between the varnish image master data [Dv] and the detection varnish image data are calculated by the following formulas (7) and (8), respectively. The movement deviation amounts SvX and SvY as second movement deviation correspond to a movement difference between center of gravity of the position reference points (P1, P2, P3, and P4) on the varnish image master data [Dv] and center of gravity of position reference points (Pv1, Pv2, Pv3, and Pv4) on the detection background image data.
SvX={(xv1+xv2+xv3+xv4)/4)}−{(x1+x2+x3+x4)/4}  formula (7)
SvY={(yv1+yv2+yv3+yv4)/4)}−{(y1+y2+y3+y4)/4}  formula (8)
<Discriminating Processing and Correcting Means Determining Processing>

Discrimination as to whether or not the positional deviation occurs between the toner image and the varnish image which are formed on the N-th recording material S is made in “discriminating processing” (described later) (S6). In the case where the positional deviation does not occur (No of S6), the main controller101causes the processing to jump to processing of a step S7. In the case where the positional deviation occurs (Yes of S6), the main controller101carries out “correcting means determining processing” (S10) (described later).

InFIG.9, a flowchart of the “discriminating processing” (S6ofFIG.8) is shown. As shown inFIG.9, the main controller101discriminates whether or not the movement deviation amount QX is larger than a threshold QXT (first deviation amount) or the movement deviation amount QY is larger than a threshold QYT (first deviation amount) (S31). In the case where the movement deviation amount QY is larger than the threshold QXT or the movement deviation amount QY is larger than the threshold QYT (Yes of S31), the main controller101discriminates that the “positional deviation” (S32).

In the case where the movement deviation amount QX is not larger than the threshold QXT or the movement deviation amount QY is not larger than the threshold QYT (No of S31), the main controller101discriminates whether or not the magnification deviation amount RX in the X-direction is larger than a threshold RXT (second deviation amount) or the magnification deviation amount RY in the Y-direction is larger than a threshold RYT (second deviation amount) (S33). In the case where the magnification deviation amount RX is larger than the threshold RXT or the magnification deviation amount RY is larger than the threshold RYT (Yes of S33), the main controller101discriminates that the “positional deviation” occurs (S32). In the case where the magnification deviation amount RX is not larger than the threshold RXT or the magnification deviation amount RY is not larger than the threshold RYT (No of S33), the main controller101discriminates that the “positional deviation” does not occur (S34).

Incidentally, the above-described thresholds QXT, QYT, RXT, and RYT may be stored in advance in the image analyzing portion404or may also be appropriately inputted through the operating portion110by the user. Or, these thresholds may also be included in the background image master data [Dg] or the varnish image master data [Dv].

InFIG.10, a flowchart of the correcting means determining processing (S10ofFIG.4) is shown. As shown inFIG.10, the main controller101discriminates whether or not a movement deviation amount SgX or SgY of the toner image (detection image) relative to the background image master data [Dg] is larger than an associated movement deviation amount SvX or SvY of the varnish image (detection image) relative to the varnish image master data [Dv] (S41). In the case where the movement deviation amount SgX or SgY of the toner image (detection image) is larger than the associated movement deviation amount SvX or SvY of the varnish image (detection image) (Yes of S41), the main controller101selects the image forming apparatus100as a movement deviation amount correcting means M (S42). On the other hand, in the case where the movement deviation amount SgX or SgY of the toner image (detection image) is not larger than the associated movement deviation amount SvX or SvY of the varnish image (detection image) (No of S41), the main controller101selects the varnish coater200as the movement deviation amount correcting means M (S43).

Thus, the main controller101selects the image forming apparatus100or the varnish coater200when an associated movement deviation of the position reference points on the detection image data relative to the position reference points on the image master data is larger and is selected as a movement deviation amount correcting object. That is, the movement deviation correction is made for eliminating the movement deviation in the toner image formation or in the varnish image formation. In this embodiment, the movement deviation correction is made by the image forming apparatus100or the varnish coater200of which movement deviation caused thereby is larger.

<Calculation of Correcting Amount>

Returning to the description ofFIG.4, the main controller101makes calculation of a correction amount (S11). The movement deviation amount correction is made by changing the image master data so that both the movement deviation amounts QX and QY calculated in the detection images become “0”. In this embodiment, correction depending on a movement deviation correction amount is made by the apparatus selected in the step S10. In the case where the image forming apparatus100is selected for correcting the movement deviation, correction for moving the toner image in the X-direction by “-QX” and in the Y-direction by “-QY” is made by the image forming apparatus100. That is, the image forming apparatus100forms the toner image by correcting the background image master data [Dg] with use of the movement deviation correction amount in subsequent image formation (re-printing of the image on the N-th sheet). By the control in this embodiment, relative to part (a) ofFIG.8, as shown in part (b) ofFIG.8, a state in which a gravity center position of the rectangular region constituting the position reference points of the toner image coincides with a gravity center position of the rectangular region constituting the position reference points of the varnish image is formed.

On the other hand, in the magnification deviation amount correction, magnification of the toner image of the background image master data [Dg] is made so that both the magnification deviation amounts RX and RY calculated in the detection image come “1” and then the image is formed. For example, as shown in part (a) ofFIG.8, correction such that the toner image is magnified (enlarged) in the X-direction by “1/RX time” and in the Y-direction by “1/RY time” on the basis of a gravitation center position of the rectangular region constituting the position reference points of the toner image is made by the image forming apparatus100. That is, the image forming apparatus100forms the toner image by changing the magnification of the toner image of the background image master data [Dg] with use of a magnification deviation correction amount in subsequent image formation (re-printing of the image on the N-th sheet). By the control in this embodiment, relative to part (a) ofFIG.8, as shown in part (b) ofFIG.8, correction is made so that the toner image corrected in the movement deviation amount in the above-described manner coincides with the varnish image.

On the other hand, in the case where the varnish coater200is selected for correcting the movement deviation, correction for moving the varnish image in the X-direction by “-QX” and in the Y-direction by “-QY” is made by the varnish coater200. The varnish coater200forms the varnish image by correcting the varnish image master data [Dv] with use of a movement deviation correction amount in subsequent image formation (re-printing of the image on the N-th sheet). Incidentally, even in the case where the varnish coater200is selected as the correcting means, as regards the magnification deviation, the toner image magnification of the background image master data [Dg] is changed with use of the magnification deviation amounts (1/RX time and 1/RY time), and then the toner image is formed by the image forming apparatus100.

Returning toFIG.4, in the case where the main controller101executes calculation of the correction amount (S11), the N-th recording material S (first recording material) subjected to image inspection is discharged on the NG tray400b(S12). In this case, the main controller101discriminates that the positional deviation of the image occurs on the recording material S, and the processing returns to the processing of the step S2without updating the counter “N”. That is, the image formation of the image on the N-th recording material S subjected to the image inspection is carried out again (re-printing). Thus, in the case where the positional deviation occurs on the N-th sheet, the background image master data [Dg] and the varnish image master data [Dv] are corrected by the above-described movement deviation amount and the above-described magnification deviation amount, and the corrected background image master data [Dg] and the corrected varnish image master data [Dv] are applied to the image formation of the image on the N-th recording material S and subsequent image forming processes of the images on an (N+1)-th recording material S and later.

On the other hand, in the case where the positional deviation does not occur (No of S6), the main controller101discharges the N-th recording material S (second recording material) subjected to the image inspection onto the OK tray400a(S7). Then, the main controller101discriminates whether there is a subsequent ((N+1)-th) recording material S subjected to continuous image formation and the image forming job is continued or there is no subsequent ((N+1)-th) recording material S subjected to the continuous image formation and the image forming job is ended (S8). In the case where the image forming job is ended (Yes of S8), the main controller101ends the “recording material output processing”. In the case where the image forming job is not ended (No of S8), the main controller101counts up the counter “N” (S9), and the processing returns to the processing of the step S2.

As described above, in this embodiment, the positional deviation between the toner image and the varnish image is corrected on the basis of an inspection result of the toner image and the varnish image on the recording material S by the image inspection apparatus400and the image master data of the toner image and the varnish image which are formed on the recording material S. At that time, the magnification deviation (RX, RY) between the toner image and the varnish image read by the image inspection apparatus400, the movement deviation (SgX, SgY) of the toner image read by the image inspection apparatus400relative to the toner image based on the background image master data, and the movement deviation (QX, QY) of the toner image read by the image inspection apparatus400relative to the varnish image read by the image inspection apparatus400are calculated. On the basis of these magnification deviation and movement deviation, only the background image master data or the background image master data and the varnish image master data are corrected, and the toner image and the varnish image are formed on the recording material S while the positional deviation of the toner image and the varnish image are automatically corrected during the image forming job. Thus, even in the case where the “magnification deviation” and the “movement deviation” simultaneously can occur when the toner image and the varnish image are formed on the recording material S, it is possible to prepare a recording material S on which the toner image and the varnish image do not cause such positional deviation.

Second Embodiment

Next, a second embodiment will be described usingFIGS.11and12. As described above, in the first embodiment, the toner image and the varnish image which are formed on the N-th recording material S are inspected, and correction of positional deviation of the images on the N-th sheet is made on the basis of detection image data of the toner image and the varnish image. Thereafter, the positional deviation amounts at that time are applied to image formation of the image on an (N+1)-th recording material S (seeFIG.4).

However, the toner image formed on the recording material S is capable of fluctuating in magnification with respect to the feeding direction so as to more contract with a larger toner coverage. For example, as shown inFIG.11, in the case where the toner coverage is “0%”, the toner image is hard to contract (magnification: “100%”), but the toner image is capable of contracting so as to be magnification of “99%” in the case where the toner coverage is “50%” and magnification of “98%” in the case where the toner coverage is “100%”. This is because a rotational speed of the intermediary transfer belt80is made higher with the toner coverage closer to “100%” and becomes high relative to a feeding speed of the recording material S, and thus the toner image is formed on the recording material S so as to contract in the feeding direction. Incidentally, in this embodiment, the toner coverage refers to a proportion (areal ratio) of a toner application amount of the toner image formed on the recording material S in the case where the toner application amount of the toner image when the toner image is formed on entirety of, for example, an A4 sheet is taken as “100%”.

For example, in the case where the toner coverage of the N-th sheet is “50%” or more and the toner coverage of the (N+1)-th sheet is less than “50%”, the toner image can cause a magnification difference of “2%”. Therefore, in the first embodiment, in the case where an image forming job such that image formation in which the toner coverage is “50%” (threshold) or more and image formation in which the toner coverage is less than “50%” are carried out continuously and alternately, there is a liability that the magnification deviation of “2%” repetitively occurs every (one) sheet of the recording material S. This is because a magnification deviation correction amount of “RY=100/98=102%”, for example, when the toner coverage of the N-th sheet is “50%” or more is also applied to the image formation in which the toner coverage of the (N+1)th sheet is less than “50%”.

Further, in the case where the number of times of fixing is different between the image formation of the N-th sheet and the image formation of the (N+1)-th sheet, the magnification difference is liable to occur between the magnification deviation of the N-th sheet and the magnification deviation of the (N+1)-th sheet. That is, in the case of double-side printing, after the toner image is fixed on a first (one) side of the recording material S, the toner image is fixed on a second (the other) side. That is, in the case of one-side printing, the recording material S passes through the fixing device50in the number of times of fixing of “one time”, i.e., once, and in the case of the double-side printing, the recording material S passes through the fixing device50in the number of times of fixing of “two times”, i.e., twice. In the case where the recording material S passes through the fixing device50twice, compared with the case where the recording material S passes through the fixing device50once, the recording material S can be more contracted by the influence of heating by the fixing device50. Incidentally, pieces of information on the toner coverage, the one-side printing, and the double-side printing are included in the background image master data [Dg].

<Recording Material Output Processing>

InFIG.12, recording material output processing in the second embodiment is shown. Incidentally, in the recording material output processing in the second embodiment, processes similar to the processes in the recording material output processing (seeFIG.4) in the first embodiment are represented by the same step numbers, and will be briefly described or omitted from description.

As shown inFIG.12, every time when a single image forming job is started, the main controller101performs initialization such that an initial value “1” is set for a counter “N” for holding the number of sheets subjected to image formation during execution of the image forming job (S1). Then, the main controller101acquires the background image master data [Dg] and the varnish image master data [Dv], and acquires a background image forming condition C [N] from the background image master data [Dv] (S21). As the background image forming condition C [N], the main controller101acquires information on the toner coverage, the one-side printing, or the double-side printing. On the basis of the acquired background image forming condition C [N], the main controller101acquires a magnification correction value from a correction table shown in a table 1 (S22).

TABLE 1TONER COVERAGENTF*1: 1NTF*1: 250%≤MCV*2: 2%MCV*2: 5%≤50%MCV*2: 1%MCV*2: 4%*1“NTF” is the number of times of fixing.*2“MCV” is the magnification correction value.

As shown in the table 1, in the correction table, the magnification correction values are defined. In this embodiment, in the case where the toner coverage is “50% or more” and the number of times of fixing is “1”, the magnification correction value of “2%” is defined. In the case where the toner coverage is “50% or more” and the number of times of fixing is “2”, the magnification correction value of “5%” is defined. In the case where the toner coverage is “less than 50%” and the number of times of fixing is “1”, the magnification correction value of “1%” is defined. In the case where the toner coverage is “less than 50%” and the number of times of fixing is “2”, the magnification correction value of “4%” is defined. That is, the magnification correction value (second magnification correction value) in the case where the toner coverage is “less than 50%” is smaller than the magnification correction value (first magnification correction value) in the case where the toner coverage is “50% or more”. Further, the magnification correction value (second magnification correction value) in the case where the number of times of fixing is “2” is larger than the magnification correction value (first magnification correction value) in the case where the number of times of fixing is “1”.

Returning to description ofFIG.20, the main controller101causes the image forming apparatus100to form the toner image on N-th recording material S and causes the varnish coater200to form the varnish image on the N-th recording material S (S2). In the step 2 and later, the processes of the steps S3to S9, S10, and S11are the processes similar to the processes in the above-described first embodiment.

In the second embodiment, in the case where the positional deviation occurs on the N-th sheet (Yes of S6), the background image master data [Dg] and the varnish image master data [Dv] are corrected by the calculated movement deviation amount and the calculated magnification deviation amount, and the corrected background image master data [Dg] and the corrected varnish image master data [Dv] are applied to the image formation of the image on the N-th recording material S (re-printing).

However, in the second embodiment, in the case where the positional deviation occurs on the N-th recording material S (Yes of S6), the main controller101calculates the magnification deviation amounts between the background image master data and the varnish image master data (S23). The magnification deviation amounts TgX and TgY between the background image master data and the varnish image master data are calculated by formulas (9) and (10) shown below. Each of the magnification deviation amounts TgX and TgY as second magnification deviation corresponds to a ratio between a length of one side of a rectangular region constituting position reference points on the background image master data and a length of one side of a rectangular region constituting position reference points on the detection background image data (see part (b) ofFIG.5).
TgX=(xg4−xg1)/(x4−x1)  formula (9)
TgY=(yg4−yg1)/(y2−y1)  formula (10)

Then, the main controller101updates the correction table (table 1) on the basis of the calculated magnification deviation amounts between the background image master data and the detection background image data (S24). Thereafter, the main controller101discharges the N-th recording material S subjected to the image inspection onto the NG tray400b(S12), and the processing returns to the processing of the step S2. For example, the correction magnification relative to the toner coverage is as shown inFIG.11, but somewhat deviation can occur due to various conditions of the main assembly of the image forming apparatus100. The main controller101acquires this deviation from a detection result by the image inspection apparatus400and changes the correction table to a correction table in which the acquired deviation is taken into consideration. For example, in the case where the magnification correction value which is assumed as “2%” at the toner coverage of “100%” was 1% in actuality, the main controller101updates the magnification correction value from “2%” to “1%”.

In the case of the second embodiment, after the discharging of the step, i.e., in order to form the image on the (N+1)-th recording material S. Then, the main controller101acquires the information on the toner coverage of the toner image, the one-side printing, or the double-side printing from the background image master data [Dg] for forming the image on the (N+1)-th recording material S (S21). The main controller101acquires the magnification correction value from the correction table shown in the table 1 on the basis of the acquired information on the toner coverage, the one-side printing, or the double-side printing (S22). The main controller101causes the image forming apparatus100to form the toner image on the (N+1)-th recording material S (S2), but at that time, the magnification deviation amount calculated when the recording material S is the N-th recording material S is corrected by the magnification correction value acquired from the correction table. Then, in accordance with the magnification deviation amount after the correction, the toner image of the background image master data [Dg] is magnified and is subjected to the image formation.

As described above, in the second embodiment, by providing the correction table shown in the table 1, even in the case where the image forming job in which a magnitude of the magnification deviation between the toner image and the varnish image which are formed on the recording material S can change frequently, it is possible to prepare a recording material S with no positional deviation between the toner image and the varnish image while suppressing consumption of the recording material S.

Other Embodiments

Embodiments of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

This application claims the benefit of Japanese Patent Application No. 2022-125394 filed on Aug. 5, 2022, which is hereby incorporated by reference herein in its entirety.