JP2022168613A - Image forming apparatus - Google Patents

Abstract

To add, to an image, a decorative effect in which glossiness changes depending on a direction in which the image is seen.SOLUTION: An image forming apparatus has toner image forming means that forms a toner image on a recording material, fixing means that fixes the toner image formed on the recording material by the toner image forming means to the recording material, and control means that controls the toner image forming means and the fixing means based on image information to form an image on the recording material. The control means causes the toner image forming means to form a first toner image for applying toner to the entirety of an image area to which a decorative effect should be added and a second toner image formed of a pattern having anisotropy so that the first toner image and the second toner image overlap each other on the recording material.SELECTED DRAWING: Figure 4

Description

The present invention relates to an image forming apparatus that forms an image on a recording material.

Electrophotographic and electrostatic recording image forming apparatuses transfer a toner image formed on an image bearing member such as a photosensitive member or an intermediate transfer member to a recording material, and then fix the toner image with a fixing device. Output on the recording material as deliverables. Further, an image forming apparatus capable of controlling the glossiness of an image output as a product is known. In Patent Document 1, when an image including a plurality of image areas with different required glossiness is formed on paper, a transfer process and a fixing process are performed a plurality of times so that each image area passes through a fixing device at a different number of times. stated to be done.

JP 2013-80250 A

2. Description of the Related Art Conventionally, no image forming apparatus has been known that has a function of adding a decorative effect to an image in which the glossiness changes depending on the viewing direction of the image.

SUMMARY OF THE INVENTION The present invention provides an image forming apparatus capable of adding to an image a decorative effect in which the glossiness changes depending on the viewing direction of the image.

According to one aspect of the present invention, toner image forming means for forming a toner image on a recording material, fixing means for fixing the toner image formed on the recording material by the toner image forming means to the recording material, and image information. and a control unit for controlling the toner image forming unit and the fixing unit to form an image on the recording material based on and a second toner image having an anisotropic pattern are superimposed on the recording material. An image forming apparatus characterized by forming an image.

According to the present invention, it is possible to add to an image a decorative effect in which the glossiness changes depending on the direction in which the image is viewed.

1 is a schematic diagram of an image forming apparatus according to Embodiment 1; FIG. 1 is a schematic diagram of a fixing device according to Embodiment 1; FIG. 1 is a block diagram showing the configuration of an image forming apparatus according to Embodiment 1; FIG. FIGS. 2A to 2C are diagrams for explaining the decorative effect of fine line patterns; FIG. 4A and 4B are schematic diagrams of fine line patterns according to Example 1. FIG. 4 is a flow chart showing the execution procedure of the decoration mode according to the first embodiment; 4 is a graph showing measurement results of the decorative effect according to Example 1. FIG. 4(a) to 4(e) show examples of pattern images for adding decorative effects; 1 is a schematic diagram of a color image forming apparatus; FIG. FIG. 2 is a schematic diagram of an image forming apparatus according to a second embodiment; 9 is a flow chart showing the execution procedure of the decoration mode according to the second embodiment; The flowchart which shows the execution procedure of the decorating mode which concerns on Example 3. FIG. 9 is a graph showing measurement results of the decorative effect according to Example 3;

Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings.

First, the overall configuration of the image forming apparatus according to the first embodiment will be described. FIG. 1 is a schematic diagram showing a cross-sectional configuration of an image forming apparatus 100 according to this embodiment. This image forming apparatus 100 is a monochrome laser printer that forms an image on a recording material P using an electrophotographic method. As the recording material P, paper such as plain paper and thick paper, plastic film, cloth, surface-treated sheet material such as coated paper, special-shaped sheet material such as envelopes and index paper, etc. A variety of sheets with different thicknesses can be used.

The image forming apparatus 100 includes an image forming section 50 including a process cartridge 5 and a transfer roller 6 (transfer member) as toner image forming means for forming a toner image on the recording material P. As shown in FIG. The process cartridge 5 has a photosensitive drum 1 as an image carrier (electrophotographic photosensitive member), a charging roller 2 as charging means, a developing roller 3 as developing means, and a cleaning blade 4 as cleaning means. In this embodiment, a developing unit including a photosensitive drum 1, a charging roller 2 and a developing roller 3, and a cleaning unit including a cleaning blade 4 are configured as a process cartridge 5 to be detachable from the main body of the image forming apparatus 100. .

The image forming apparatus 100 also includes a fixing device 30 as fixing means for fixing the toner image formed on the recording material P by the toner image forming means. Further, the image forming apparatus 100 includes a feed cassette 13 , a feed roller 14 , a transport roller pair 15 , a top sensor 17 , a transfer roller 6 , a fixing device 30 , a discharge roller pair 20 , a motor 18 and a control section 60 . . The motor 18 is a driving source (driving means) for supplying a driving force to the image bearing member and members for transporting the recording material P. As shown in FIG. In this embodiment, a single motor 18 provides driving force for a plurality of members such as the feed roller 14, the transport roller pair 15, the photosensitive drum 1, the fixing device 30, the discharge roller pair 20, and the like.

The photosensitive drum 1 is a drum-shaped (cylindrical) photosensitive member, and is rotationally driven counterclockwise in the drawing at a predetermined peripheral speed (process speed) during image formation. The charging roller 2 uniformly charges the peripheral surface of the photosensitive drum 1 to a predetermined polarity and potential (primary charging). The photosensitive drum 1 that has been primarily charged is scanned and exposed (irradiated) with a laser beam emitted from the exposure device 7 on the surface to be charged. The exposure device 7 as exposure means outputs a laser beam which is ON/OFF modulated according to the video signal transmitted from the control section 60 .

A video signal is generated based on data obtained by developing image information to be formed on an image carrier in the main scanning direction and the sub-scanning direction of the exposure device 7, and is sent to the exposure device 7 as a signal specifying the amount of toner for each pixel. Refers to a transmitted signal (time-series digital pixel signal). Image information representing an image to be formed on the recording material P is input from an external device (information processing terminal) such as an image scanner or computer connected to the image forming apparatus 100 . Scanning exposure by the exposure device 7 removes charges in the exposed area (bright area) on the peripheral surface of the photosensitive drum 1 , and an electrostatic latent image corresponding to image information is formed on the peripheral surface of the photosensitive drum 1 . . The developing roller 3 carries developer containing toner on its surface, supplies the toner to the photosensitive drum 1, and develops the electrostatic latent image formed on the circumferential surface of the photosensitive drum 1 as a toner image. In this embodiment, a reversal development method is used in which toner is adhered to a bright area during exposure for development.

The feeding cassette 13 is detachable from the image forming apparatus 100, and accommodates the recording materials P stacked thereon. The recording material P in the feeding cassette 13 is fed while being separated one by one by driving the feeding roller 14 based on the feeding start signal of the control unit 60 , and is conveyed to the conveying roller pair 15 . be. The recording material P is further introduced into a transfer nip Nt as a transfer portion formed between the photosensitive drum 1 and the transfer roller 6 by the conveying roller pair 15 .

The top sensor 17 is installed on the transport path between the transport roller pair 15 and the transfer nip Nt, and detects the passage timing of the leading edge of the recording material P transported from the transport roller pair 15 . The control unit 60 adjusts the writing timing of the electrostatic latent image by the exposure device 7 according to the leading edge timing of the recording material P detected by the top sensor 17 . That is, the writing timing is controlled so that the leading edge of the toner image on the photosensitive drum 1 reaches the transfer nip Nt when the leading edge of the recording material P reaches the transfer nip Nt.

The recording material P introduced into the transfer nip Nt is nipped and conveyed between the photosensitive drum 1 and the transfer roller 6 at the transfer nip Nt. During this time, a transfer voltage controlled to a predetermined voltage value is applied to the transfer roller 6 from a transfer voltage application power source (not shown). A toner image carried on the peripheral surface of the photosensitive drum 1 is electrostatically transferred to the surface of the recording material P by applying a transfer voltage having a polarity opposite to the normal charging polarity of the toner to the transfer roller 6 . be. The recording material P onto which the toner image has been transferred is conveyed from the transfer nip Nt to the fixing device 30 . After passing through the transfer nip Nt, the peripheral surface of the photosensitive drum 1 is cleaned by the cleaning blade 4 to remove residual toner, paper dust, etc., and is primarily charged again for the next image formation.

The fixing device 30 has a fixing film 31 and a pressure roller 32 (details will be described later), and nips and conveys the recording material P at a fixing nip Nf. During this time, the toner image on the recording material P1 is heated by the fixing film 31 controlled to have a predetermined temperature (fixing temperature), whereby the toner image is fixed onto the recording material P. FIG. The recording material P that has passed through the fixing device 30 is discharged and stacked on a discharge tray provided above the image forming apparatus 100 by a discharge roller pair 20 that discharges the recording material P. FIG. Image formation on one sheet of recording material P is completed by the series of operations described above.

In the case of double-sided printing, the recording material P on which an image is formed on the first side by passing through the transfer nip Nt and the fixing nip Nf is conveyed to the discharge roller pair 20, and then the discharge roller pair 20 is discharged at a predetermined timing. is pulled back into the image forming apparatus 100 by rotating in the reverse direction at . The pulled-back recording material P is directed to the image forming section 50 again in a state in which the first side and the opposite second side are exchanged by a pair of double-sided conveying rollers 41 and 43 provided in the double-sided conveying path 42 . be transported. Then, the recording material P on which the image is formed on the second surface by being conveyed again from the conveying roller pair 15 via the transfer nip Nt and the fixing nip Nf is discharged to the discharge tray by the discharge roller pair 20 . In other words, the double-sided conveying path 42 functions as a re-conveying section that conveys the recording material that has passed through the toner image forming means and fixing means toward the toner image forming means or fixing means again. Further, in this embodiment, the discharge roller pair 20 functions as a reversing unit for conveying the recording material to the re-conveying section in a state where the recording material is reversed.

By repeating the above operations, images can be formed on a plurality of recording materials P one after another.

<Fixing Means>
Next, the configuration of the fixing device 30 as fixing means mounted in the image forming apparatus 100 will be described. FIG. 2 is a schematic diagram showing a cross section of the fixing device 30 of Example 1 cut along a plane perpendicular to the sheet width direction (the main scanning direction during image formation, the rotation axis direction of the pressure roller 32) at the fixing nip Nf. be. For convenience of explanation, the fixing device 30 shown in FIG. 2 is shown in a state in which the orientation of the fixing device 30 in FIG. 1 is rotated by a predetermined angle.

The fixing device 30 includes a fixing film 31 , a pressure roller 32 , a nip forming member 37 having a heater 33 and a heater holder 34 , a pressure stay 35 and an entrance guide 36 .

The fixing film 31 is a tubular (endless) film member having an elastic layer 312 and a surface layer 313 provided on the outer peripheral surface of a base layer 311 . The elastic layer 312 is made of a heat-resistant elastic material such as silicone rubber from the viewpoint of improving the fixability and making the gloss uniform. The surface layer 313 is made of fluororesin or the like having heat resistance and good releasability from the viewpoint of improving the separability from the recording material P and suppressing offset in which a part of the toner of the toner image T adheres to the surface layer 313 . Consists of material.

The pressure roller 32 as a pressure member has a core shaft portion 321 , at least one or more elastic layers 322 , and a surface layer 323 . The elastic layer 322 is made of a heat-resistant elastic material such as silicone rubber or fluororubber so as to secure the width of the fixing nip Nf, which will be described later. The surface layer 323 is made of a heat-resistant material such as a fluororesin having good releasability in order to prevent contamination by toner or paper dust. In this embodiment, the pressure roller 32 has an outer diameter of 25 mm.

The heater 33 is a plate-shaped heating element that rapidly heats the fixing film 31 while being in contact with the inner peripheral surface of the fixing film 31 . The heater 33 has a heating resistor that generates heat when energized, and generates heat when a current is supplied from a current circuit mounted on the image forming apparatus 100 . The temperature of the heater 33 is detected by a thermistor 331 as temperature detecting means which is in contact with the back surface of the substrate. Based on the detection signal from the thermistor 331, the control unit 60 controls the energization of the heater 33 so that the heater 33 reaches a predetermined target temperature.

The heater holder 34 holds the heater 33 . That is, the heater 33 and the heater holder 34 function as a nip forming member 37 having a heating element for heating the film and arranged inside the film. The pressure stay 35 is made of a member having rigidity, and applies pressure received from a pressure means such as a spring (not shown) to the pressure roller 32 via the heater holder 34 . This pressing force forms a fixing nip Nf as a nip portion having a predetermined width between the nip forming member 37 and the pressure roller 32 which are pressed against each other with the fixing film 31 interposed therebetween.

In the fixing device 30 of this embodiment, the heater 33 is in direct contact with the inner peripheral surface of the fixing film 31. However, a plate-like or sheet-like plate having high thermal conductivity is placed between the heater 33 and the fixing film 31. (for example, a sheet-like member made of ferroalloy or aluminum) may be arranged. That is, the heater 33 may use the nip forming member 37 configured to heat the fixing film 31 via a sliding member that slides on the inner peripheral surface of the fixing film 31 .

Next, a fixing process in the fixing device 30 will be described. The pressure roller 32 is rotationally driven in the direction of arrow r1 by a motor 18 (FIG. 12), which is driving means. As the pressure roller 32 rotates, the fixing film 31 rotates in the direction of the arrow r2. The heater 33 heats the fixing film 31 by rapidly increasing its temperature when energized. With the heater 33 controlled to a predetermined target temperature, the recording material P is guided along the entrance guide 36 to the fixing nip Nf, and is nipped and conveyed in the conveying direction D by the fixing film 31 and the pressure roller 32 . During the conveying process, the toner on the recording material P is heated and pressurized, and the unfixed toner image T is fixed on the recording material P. FIG.

<Control block diagram>
Next, the hardware configuration of the image forming apparatus 100 according to the first embodiment will be explained using the block diagram of FIG. The image forming apparatus 100 has a control section 60 , an image forming section 50 , an HDD 73 and a computing section 74 .

The control unit 60 as control means is a control circuit including a CPU that executes a control program to control the entire image forming apparatus 100, a RAM that is a work memory, and a ROM that stores the control program. The ROM is an example of a non-transitory storage medium that stores control programs for the image forming apparatus 100 . The control unit 60 has an image formation control unit 61 for operating the image forming unit 50 based on image information to perform an image forming operation. The control unit 60 also has a fixing temperature control unit 62 that controls the temperature of the heater 33 of the fixing device 30 to a predetermined temperature based on the detection result of the thermistor 331, which is a temperature detection element.

HDD 73 is a hard disk drive. The HDD 73 not only stores system software and image data, but also stores decoration information of the decoration mode used in this embodiment. As the storage means, a writable non-volatile memory such as a semiconductor memory may be used in addition to the hard disk. The calculation unit 74 as calculation means creates image data used for image formation by the image formation control unit 61 from the decoration information stored in the HDD 73 and the decoration information specified by the user. Details will be explained later.

The control unit 60 is connected to a network such as LAN via a network I/F 70 . The network I/F 70 performs communication such as image information and execution instructions for image formation between an external device on the network and the image forming apparatus 100 .

<Description of decoration method>
An image decoration method according to the present embodiment will be described. In this embodiment, it is possible to add to the image a decorative effect that makes the glossiness of the image different depending on the viewing direction of the image.

FIG. 4A shows a schematic diagram of a thin line pattern used in this embodiment. The thin line pattern is a parallel line pattern in which parallel straight lines extending in the same predetermined direction are arranged side by side at predetermined intervals. The width of the thin line is X1 in terms of the number of dots, and the interval between the thin lines is X2 in terms of the number of dots. Since the image forming apparatus in this embodiment has a resolution of 600 dpi, the size of one dot corresponds to 42 μm. In this embodiment, a fine line pattern shown in FIG. 4A is superimposed and transferred onto a toner image (hereinafter referred to as a base image) formed on a recording material according to image information to obtain a decorative effect. come true.

As shown in FIG. 4A, when viewed from a direction perpendicular to the surface of the recording material on which the fine line pattern is recorded (when viewed vertically with the recording material placed on a horizontal surface), the fine line pattern Let the angle parallel to the direction of each fine line of the pattern be 0°, and the angle perpendicular to the direction of each fine line be 90°. As shown in FIG. 4(b), the amount of light specularly reflected (specularly reflected) by the fine line pattern when viewed from the direction of 0° with respect to the fine line pattern is as shown in FIG. 4(c). On the other hand, it increases compared to when viewed from the direction of 90°.

This is because, when viewed from a direction of 90° to the fine line pattern, part of the light incident on the recording material from the light source is "kicked" by the walls of the fine lines, and the reflected light in the specular direction is reduced. It is from. In other words, part of the light incident from the direction intersecting the fine line pattern is reflected by the stepped portion between the fine lines and the area between the fine lines, resulting in specular reflection by a virtual plane along the surface of the recording material. This is because it is reflected in a direction different from the direction. On the other hand, light incident in a direction parallel to the fine line pattern rarely hits the walls of the fine lines, and is likely to be reflected in the specular direction on the surface of the fine lines or in the area between the fine lines. That is, when the recording material is viewed in a direction intersecting the normal direction of the surface of the recording material, the glossiness of the fine line pattern is high (high glossiness) when viewed along the fine line pattern in the normal direction. Become. Conversely, when viewed in the normal direction and in a direction intersecting the fine line pattern, the glossiness of the fine line pattern is low (low gloss).

The property of the fine line pattern that the glossiness changes depending on the viewing direction as described above (anisotropy in terms of glossiness) is obtained by superimposing the fine line pattern on another toner image formed with a substantially uniform thickness on the recording material. The same is true when a pattern is formed. Therefore, in the image forming apparatus 100 of the present embodiment, the user instructs a decoration mode for outputting an image to which a decorative effect is added using a thin line pattern and a normal mode for outputting an image without using a thin line pattern. configured to run selectively based on

<Decoration mode>
In this embodiment, when adding a decorative effect by a thin line pattern, the decoration level (the width of the glossiness change depending on the viewing direction of the image) can be specified in four stages. FIG. 5 is a schematic diagram showing the difference in fine line patterns for each decoration level. An upper left image R0 represents a solid image formed at the decoration level "0" (normal mode), and no thin line pattern is formed on the solid image. Image R1 represents fine line patterns used at decoration level "1", image R2 represents decoration level "2", and image R3 represents fine line patterns used at decoration level "3". The difference in glossiness depending on the direction becomes large. As will be described later, the decoration level can be controlled by changing the width and spacing of the fine lines of the fine line pattern. FIG. 5 is a schematic diagram for explaining that the decoration level can be controlled by changing the width and spacing of the fine lines of the fine line pattern. need not be identical to

<Control flow>
A flowchart showing the execution procedure of the decoration mode of the present embodiment will be described with reference to FIG. Each step of this flow described below is achieved by the CPU of the control unit 60 (FIG. 3) executing the control program from the ROM.

Upon receiving image information from an external device via the network I/F 70, the control unit 60 executes a series of operations (print job) for forming an image on a recording material and discharging the recording material. When the print job is started, in S101, the control unit 60 refers to the setting information of the print job received from the external device, and determines whether to form the image in the normal mode or the decoration mode. The decoration mode is the first mode of this embodiment that causes the toner image forming means to form the first toner image and the second toner image. In the case of the decoration mode, the process proceeds to S102, and the calculation unit 74 creates image data corresponding to the decoration mode.

In this embodiment, for an image area designated to apply a decorative effect (decorative designated area), a solid image is formed as a base image in the first image forming operation, and a solid image is formed in the second image forming operation. A fine line pattern is formed according to the decoration level. A solid image is a toner image (first toner image) corresponding to image information. In other words, the solid image is a solid image for applying toner with a substantially uniform thickness (toner amount) over the entire image area to which a decorative effect is to be added (hereinafter referred to as a designated decorative area). It is an image. An "image area (printing area)" refers to, for example, an area inside the contour of text in the case of a text image, or an area inside a figure in the case of a solid figure. On the other hand, the fine line pattern is a pattern image that is superimposed on the first toner image on the recording material in order to add a decorative effect, and is a toner image (second toner image) that includes parallel line patterns in the same direction. . The thin line pattern (second toner image) for adding a decorative effect is preferably a toner image using toner of the same color as the base image (first toner image).

In S102 above, the calculation unit 74 generates the image data for forming the background image in the image forming unit 50 and the thin line pattern based on the image information and the setting information of the decoration level received from the external device. 50 and image data to be formed. The control unit 60 uses the base image and the fine line pattern image data created by the calculation unit 74 to perform the following processing.

In S103, the control unit 60 executes the first image forming operation to form a solid image as a background image in the designated decoration area of the recording material. At this time, the control unit 60 transmits a video signal generated based on the image data of the base image created by the calculation unit 74 to the exposure device 7, thereby causing the image forming unit 50 to transfer the base image (second base image) onto the recording material P. 1 toner image) is formed. The recording material P to which the base image has been transferred is conveyed to a fixing device 30 and undergoes a fixing process.

In S104, the control unit 60 conveys the recording material on which the base image is formed by the discharge roller pair 20 and the double-sided conveying path 42, and the surface of the recording material on which the base image is formed faces the photosensitive drum 1 again at the transfer nip Nt. It should be the surface to be printed (transfer surface). Specifically, after the recording material P to which the background image has been transferred at the transfer nip Nt passes through the fixing device 30 and the trailing edge of the recording material P passes through the position of the switching guide 40 (FIG. 1), the controller 60 switches the position of the switching guide 40 and rotates the discharge roller pair 20 in the reverse direction. As a result, the recording material P is pulled back into the image forming apparatus and transported to the transfer nip Nt again via the double-sided transport path 42 . At this point, since the surface (second surface) of the recording material P opposite to the surface (first surface) on which the background image is formed faces the photosensitive drum 1, the thin line pattern is not transferred. . After the recording material P passes through the fixing device 30 for the second time, the control unit 60 executes the second reverse conveyance by the discharge roller pair 20, and conveys the recording material P to the transfer nip Nt via the double-sided conveyance path 42. . As a result, the recording material P reaches the transfer nip Nt again in a state in which the surface (first surface) on which the base image is formed faces the photosensitive drum 1 .

In S105, the control unit 60 performs the second image forming operation to form a thin line pattern superimposed on the background image already formed in the designated decoration area of the recording material. At this time, the control unit 60 transmits a video signal generated based on the image data of the fine line pattern created by the calculation unit 74 to the exposure device 7, thereby causing the image forming unit 50 to print the fine line pattern (three-line pattern) on the recording material P. 2 toner image) is formed. Subsequently, the recording material P is conveyed to the fixing device 30 and undergoes the second fixing process. In S106, the recording material P is discharged by the discharge roller pair 20, and the printing job for one recording material P in the decoration mode is completed.

On the other hand, if the setting of the print job is the normal mode in S101, the process proceeds to S107, and the control unit 60 performs normal image formation. In this case, the calculation unit 74 does not create image data of the fine line pattern. The control unit 60 transmits a video signal generated based on the image information received from the external device to the exposure device 7 to cause the image forming unit 50 to form a toner image corresponding to the image information on the recording material P. Further, in this case, the recording material P onto which the toner image corresponding to the image information is transferred at the transfer nip Nt and subjected to the fixing process by the fixing device 30 is discharged by the discharge roller pair 20 as it is. That is, in the case of NO in S101, the controller 60 causes the toner image forming means to form a toner image corresponding to the image information without causing the toner image forming means to form the second toner image, and causes the fixing means to correspond to the image information. A second mode of fixing the toner image is executed.

Although the operation of forming an image with a decorative effect on one side of the recording material P has been described here, an image with a decorative effect on both sides of the recording material P can also be formed. In this case, the control unit 60 forms the base image of the first surface in the first image forming operation, the base image of the second surface in the second image forming operation, and the second surface in the third image forming operation. The thin line pattern on the first surface may be formed by the fourth image forming operation to form the thin line pattern on the second surface.

<Decoration level setting>
Here, the fine line pattern adjustment according to the setting of the decoration level will be described. FIG. 7 shows the glossiness (gloss value) measured from the direction of 0° or 90° with respect to the fine line pattern and the difference (gloss difference Δ) when the line width and interval of the fine line pattern are changed. ing. Here, the fine line width X1 and the fine line spacing X2 are the same value, and the glossiness of the fine line pattern created by changing the values of X1 and X2 (the number of dots of the fine line and the spacing) in the range of 1 dot to 10 dots, And the glossiness of a solid image not forming a fine line pattern was measured. The recording material used for the measurement is "Futura 100 lb (manufactured by VERSO), basis weight 148 g/m ² ". Further, the glossiness was measured at an incident angle of 75° using PG-1 (manufactured by Nippon Denshoku Industries).

From the results shown in FIG. 7, it can be seen that the decorative effect changes depending on the roughness of the fine line pattern. For example, the gloss difference Δ is maximized when the fine line width X1 and the fine line interval X2 are 6 dots each, and becomes smaller when the fine line width X1 and the fine line interval X2 are 10 dots each than 6 dots. In other words, by changing the width X1 of the fine lines and the interval X2 of the fine lines, it is possible to change the level of the decorative effect that causes a difference in gloss depending on the viewing direction of the image.

In this embodiment, when the decoration level is 0, a solid image (only the base image) is formed. In the case of decoration level 1, a thin line pattern with a width X1 and an interval X2 of 10 dots is formed, in the case of decoration level 2, a thin line pattern with a width X1 and an interval X2 of 3 dots is formed, and in the case of decoration level 3 forms a thin line pattern with a width X1 and an interval X2 of 6 dots. That is, in S102 of the flow described above, the calculation unit 74 creates image data of the fine line pattern with the width X1 and the interval X2 that are predetermined according to the setting value of the decoration level. Thus, by adjusting the fine line pattern in four stages, it is possible to control the difference in glossiness depending on the viewing direction.

It can be said that the fine line pattern with the width X1 and the interval X2 of 1 dot is the finest fine line pattern that the image forming apparatus 100 can realize. In this embodiment, the upper limit of the fine line pattern cycle is 20 dots (approximately 0.84 mm at 600 dpi). (corresponding to the fine line pattern of decoration level 3 in the example).

(Modification)
As shown in FIG. 8A, the direction of the fine line pattern for adding the decorative effect is the direction perpendicular to the conveying direction D of the recording material (the main scanning direction during image formation, the sheet width direction). , may be in other directions. For example, as shown in FIG. 8(b), thin lines parallel to the conveying direction D, and those inclined at an angle of 45° to the conveying direction D as shown in FIGS. good too. That is, as the second toner image, it is possible to selectively use a plurality of patterns each of which consists of parallel lines extending in the same direction and in which the directions in which the parallel lines extend are different from each other.

Also, the pattern image to which the decorative effect is added may be a combination of a plurality of fine line patterns with different directions illustrated in FIGS. 8(a to 8c). That is, the second toner image has a first pattern in which parallel lines in a first direction are arranged at a predetermined first interval, and parallel lines in a second direction different from the first direction are arranged at a predetermined second interval. and the second pattern may be combined. For example, in the case of a pattern combining fine line patterns in FIGS. 8A and 8B, the glossiness when viewed at an angle of 0° or 90° The pattern is anisotropic in the sense that the gloss is different when viewed at an angle of .

Moreover, the pattern image for adding a decorative effect is not limited to a pattern consisting of parallel lines as long as the pattern image has anisotropy. For example, as shown in FIG. 8E, a pattern image in which elongated rectangles in the same direction (or line segments extending in the same direction) are arranged at regular intervals is also different when viewed in the long side direction and in the short side direction of the rectangle. The degree of gloss differs depending on the case. “Anisotropy” means that the frequency of appearance of boundaries (edges) between toner image areas and non-toner image areas when a pattern image is cut along a straight line in a certain direction varies depending on the cutting direction. If the appearance frequency of the edges of the toner image is high (or low) depending on the direction of cutting, when the image is viewed from that direction, the proportion of light reflected in a direction different from the regular reflection direction at the edge portion is large ( or smaller), resulting in a difference in glossiness. In the case of the thin line patterns shown in FIGS. 8A to 8D, the number of times the boundary is crossed is 0 when cut in the direction parallel to the thin line, and the number of thin lines when cut in the direction perpendicular to the thin line. Since twice as many boundaries are passed through, the anisotropy is very high and a difference in glossiness can easily be obtained.

In this embodiment, a solid image as a base image is first transferred and fixed, and then a thin line pattern for adding a decorative effect is transferred and fixed. Alternatively, the fine line pattern (second toner image) may be transferred and fixed first, and then the solid image (first toner image) may be transferred and fixed. Even in this case, since a solid image is formed on the fine line pattern, unevenness along the direction of the fine line pattern is formed on the surface of the image on the recording material, so that the glossiness of the image varies depending on the viewing direction. . Moreover, the setting method of the decoration level is not limited to the one described above, and the decoration level may be changed in three steps or less or five steps or more (including continuation).

Although Embodiment 1 exemplifies an embodiment of a monochrome image forming apparatus, this embodiment will be described using an embodiment of a color image forming apparatus. Elements denoted by the same reference numerals as in the first embodiment have substantially the same configuration and action as those described in the first embodiment.

First, the overall configuration of the image forming apparatus of this embodiment will be described. FIG. 9 is a schematic diagram showing a cross-sectional configuration of the image forming apparatus 101 according to this embodiment. This image forming apparatus 101 is a color laser printer that forms an image on a recording material P using an electrophotographic method.

The image forming apparatus 101 includes four process cartridges 5Y, 5M, 5C, and 5K, an intermediate transfer belt unit, and a secondary transfer roller 11 (transfer member) as toner image forming means for forming a toner image on the recording material P. A forming section 50 is provided. The process cartridges 5Y to 5K are process stations that can be attached to and detached from the main body of the image forming apparatus 101. FIG. Each of the process cartridges 5Y to 5K has substantially the same structure, and uses toner of different colors, ie, yellow (Y), magenta (M), cyan (C), and black (K) toner. create a statue. Each of the process cartridges 5Y to 5K has a toner container 23, a photosensitive drum 1 as an image carrier (electrophotographic photosensitive member), a charging roller 2, a developing roller 3, a cleaning blade 4, and a waste toner container 24, respectively. An exposure device 7 is arranged below each process cartridge 5 .

During image formation, the photosensitive drum 1 is rotationally driven, and the surface of the photosensitive drum 1 is uniformly charged to a predetermined polarity and potential by the charging roller 2 . After that, the photosensitive drum 1 is exposed by the exposure device 7 . At this time, the exposure device 7 exposes the photosensitive drum 1 based on a video signal corresponding to each color component image (yellow, magenta, cyan, and black color component images) corresponding to the image information. As a result, an electrostatic latent image corresponding to each color component image is formed on the photosensitive drum 1 of each of the process cartridges 5Y to 5K. The electrostatic latent image formed on the photosensitive drum 1 is developed by being supplied with developer from the developing roller 3 and visualized as a toner image of each color. The developer is, for example, negatively charged non-magnetic one-component toner, and the electrostatic latent image is developed by a non-magnetic one-component contact development system.

The intermediate transfer belt unit includes an intermediate transfer belt 8, a drive roller 9, a secondary transfer opposing roller 10, a belt cleaning blade 21, and a belt toner box 22. As shown in FIG. The intermediate transfer belt unit also includes four transfer rollers (primary transfer rollers) 6 arranged inside the intermediate transfer belt 8 so as to face each photosensitive drum 1 . When the drive roller 9 is rotated by a motor (not shown), the intermediate transfer belt 8 is rotated, and the secondary transfer counter roller 10 is driven to rotate accordingly. Each photosensitive drum 1 rotates in the direction of the arrow, the intermediate transfer belt 8 rotates in the direction of arrow A, and a positive primary transfer bias is applied to the transfer roller 6 . As a result, the toner images on the photosensitive drum 1 are primarily transferred onto the intermediate transfer belt 8 in order from the toner image on the photosensitive drum 1Y. At this time, since the exposure start timings are synchronized so that the four-color toner images overlap each other on the intermediate transfer belt 8, a full-color toner image is formed on the intermediate transfer belt 8. FIG.

The full-color toner image carried on the intermediate transfer belt 8 is conveyed to a transfer nip Nt, which is a nip portion (secondary transfer portion) between the intermediate transfer belt 8 and the secondary transfer roller 11 . By applying a positive bias to the secondary transfer roller 11, the full-color toner image is transferred to the recording material P at the transfer nip Nt. The cleaning blade 4 of the photosensitive drum 1 is pressed against the photosensitive drum 1 to remove residual toner remaining on the surface of the photosensitive drum 1 without being primarily transferred to the intermediate transfer belt 8 and other residues on the photosensitive drum. Further, the belt cleaning blade 21 is in pressure contact with the intermediate transfer belt 8 stretched around the driving roller 9, and remains on the surface of the intermediate transfer belt 8 without being secondarily transferred onto the recording material P in the secondary transfer described later. Residual toner and other residue on the intermediate transfer belt 8 is removed.

The feeding/conveying device 12 has a feeding roller 14 for feeding the recording material P from a feeding cassette 13 containing the recording material P, and a conveying roller pair 15 for conveying the fed recording material P. Then, the recording material P conveyed from the feeding/conveying device 12 is conveyed to the transfer nip Nt by the registration roller pair 16, and the toner image is transferred thereon.

The recording material P that has passed through the transfer nip Nt is conveyed to a fixing device 30 as fixing means. The fixing device 30 is a film heating type fixing device including a fixing film 31 containing a nip forming member having a heater 33 and a pressure roller 32 that presses against the fixing film 31 . A thermistor 331 for measuring the temperature of the heater 33 is attached to the heater 33 . The recording material P undergoes a toner image fixing process by being heated and pressurized while being sandwiched and conveyed between the fixing film 31 and the pressure roller 32 at the fixing nip Nf between the pressure roller 32 and the nip forming member. After that, the recording material P is discharged to the outside of the image forming apparatus 101 by the discharge roller pair 20 .

The image forming apparatus 101 can perform double-sided printing on the recording material P. FIG. In the case of double-sided printing, after the trailing edge of the recording material P that has passed through the fixing device 30 passes the position of the switching guide 40, the position of the switching guide 40 is first switched to the double-sided conveying path side. Further, the rotation direction of the discharge roller pair 20 is switched to the double-sided conveying path 42 side by a reversing clutch (not shown) that determines the rotation direction of the discharge roller pair 20 . As a result, the conveying direction of the recording material P is reversed, and the recording material P is conveyed to the double-sided conveying path 42 . In the double-sided conveying path 42 , the recording material P is again conveyed toward the registration roller pair 16 by the double-sided conveying roller pairs 41 and 43 . After the registration roller pair 16 , the toner image is transferred and fixed to the back surface (second surface) of the recording material P in the same process as for the front surface (first surface). is discharged to the outside of the image forming apparatus 101 by . The configuration of the fixing device 30 and the hardware configuration of the image forming apparatus 101 are the same as those described with reference to FIGS. 2 and 3 in the first embodiment.

In such a color image forming apparatus 101 as well, the decoration mode can be executed in the same manner as in the first embodiment. That is, after a base image (first toner image) is formed on the recording material P, the recording material P is conveyed so that the surface on which the base image is formed faces the intermediate transfer belt 8 again at the transfer nip Nt, and the base image is formed. Then, a thin line pattern (second toner image) may be formed by superimposing the toner image.

In the case of the color image forming apparatus 101, part of the plurality of process cartridges is used to form a base image (first toner image), and the remaining part is used to form a thin line pattern for adding a decorative effect. The decoration mode can also be realized by a method of forming a (second toner image). In this way, when executing the decorating mode, the recording material P does not pass through the fixing device 30 a plurality of times, and the decorating mode can be executed in one fixing process. As an example, in FIG. 10, the cyan process cartridge 5C of FIG. 9 is replaced with a second black process cartridge 5K2. In this case, one of the black process cartridges 5K2 forms a base image, the other black process cartridge 5K forms a thin line pattern, and the base image and the thin line pattern can be simultaneously transferred onto the recording material P at the transfer nip Nt. can.

FIG. 11 shows a flowchart showing the execution procedure of the decoration mode of this embodiment. When the control unit 60 starts the print job, in S201, the control unit 60 refers to the setting information of the print job received from the external device, and selects whether to perform image formation in the normal mode (second mode) or the decoration mode (first mode). mode). In the case of the decoration mode, the process proceeds to S202, and the calculation unit 74 creates image data corresponding to the decoration mode.

In S202, the calculation unit 74 causes the process cartridge 5K2 to form a solid image, which is a base image, and causes the process cartridge 5K to form a fine line pattern, based on the image information and the decoration level setting information received from the external device. Create image data for In S203, the control unit 60 executes an image forming operation to form a background image and a thin line pattern in the designated decoration area of the recording material. At this time, the control unit 60 transmits a video signal generated based on the image data of the base image and the fine line pattern created by the calculation unit 74 to the exposure devices 7 corresponding to the process cartridges 5K2 and 5K5, thereby generating the base image. and to form a fine line pattern. Subsequently, in S204, the recording material P is conveyed to the fixing device 30 and fixed. At this time, the base image and the thin line pattern are simultaneously subjected to the fixing process. Even if the base image and fine line pattern are fixed at the same time, unevenness (differences in toner layer thickness) corresponding to the fine line pattern remains on the surface of the fixed image. A decorative effect with different glossiness can be obtained. In S205, the recording material P is discharged by the discharge roller pair 20, and the printing job for one recording material P in the decoration mode is completed.

On the other hand, if the setting of the print job is the normal mode in S201, the process proceeds to S206, and the control unit 60 performs normal image formation. In this case, the calculation unit 74 does not create image data of the fine line pattern. That is, in the case of NO in S201, the controller 60 causes the toner image forming means to form a toner image corresponding to the image information without causing the toner image forming means to form the second toner image, and causes the fixing means to correspond to the image information. A second mode of fixing the toner image is executed.

As described above, according to this embodiment, in an image forming apparatus equipped with a plurality of process cartridges, a base image and a fine line pattern are superimposed and transferred onto the recording material P, and then the fixing process is performed. That is, the toner image forming means of this embodiment includes a first image carrier that carries a toner image, a second image carrier that carries a toner image, and a recording material from the first image carrier and the second image carrier. and a transfer means for transferring the toner image to the toner image. An example of the first image carrier is the photosensitive drum 1 of the process cartridge 5K2, an example of the second image carrier is the photosensitive drum of the process cartridge 5K, and an intermediate transfer belt unit and a secondary transfer roller 11 are examples of the transfer means. is. Further, the control means causes the toner image forming means to form the first toner image on the first image carrier, forms the second toner image on the second image carrier, and causes the transfer means to form the first toner image and the toner image on the recording material. After transferring the second toner image, the first toner image and the second toner image are fixed on the recording material by fixing means. As a result, the decoration mode can be realized without repeating the re-conveyance of the recording material P using the double-sided conveying path 42, and the productivity can be improved.

In this embodiment, the thin line pattern is formed by one of the plurality of process cartridges using toner of the same color, but the thin line pattern may be formed by one of the plurality of process cartridges using toner of different colors. For example, a fine line pattern may be formed by using transparent toner instead of black toner in the process cartridge 5K.

Further, the configuration of the image forming apparatus using a plurality of process cartridges is not limited to the tandem intermediate transfer system. For example, a plurality of direct transfer type process cartridges may be arranged along the conveying path of the recording material.

As Example 3, a form in which the absolute value of glossiness can be changed will be described. In this embodiment, as in the first embodiment, the monochrome image forming apparatus 100 will be described. Elements denoted by the same reference numerals as in the first embodiment have substantially the same configuration and action as those described in the first embodiment.

In Example 1, as shown in FIG. 7, the magnitude of the glossiness (gloss value) differs depending on the width X1 and the interval X2 of the fine lines of the fine line pattern, and the decoration level (difference in glossiness depending on the viewing direction) is When changed, the absolute value of gloss also changed. In the present embodiment, following the decoration mode operation similar to that of the first embodiment, additional fixing processing is performed on the recording material P to reduce the fluctuation range of the absolute value of the glossiness.

FIG. 12 is a flow chart showing the execution procedure of the decoration mode of this embodiment. When the control unit 60 starts the print job, in S301, the control unit 60 refers to the setting information of the print job received from the external device, and selects whether to perform image formation in the normal mode (second mode) or the decoration mode (first mode). mode). In the case of the decoration mode, the process proceeds to S302, and the calculation unit 74 creates image data corresponding to the decoration mode. In S302, the calculation unit 74 generates image data for forming a base image in the image forming unit 50 and a thin line pattern based on the image information and the setting information of the decoration level received from the external device. image data to be formed on each of them.

In S303, the control unit 60 executes the first image forming operation to form a solid image as a background image in the designated decoration area of the recording material. At this time, the control unit 60 transmits a video signal generated based on the image data of the base image created by the calculation unit 74 to the exposure device 7, thereby causing the image forming unit 50 to transfer the base image (second base image) onto the recording material P. 1 toner image) is formed. The recording material P to which the base image has been transferred is conveyed to a fixing device 30 and undergoes a fixing process.

In S304, the control unit 60 conveys the recording material on which the base image is formed by the discharge roller pair 20 and the double-sided conveying path 42, and the surface of the recording material on which the base image is formed faces the photosensitive drum 1 again at the transfer nip Nt. It should be the surface to be printed (transfer surface). The transfer procedure is the same as in the first embodiment. In S305, the control unit 60 performs the second image forming operation to form a thin line pattern superimposed on the background image already formed in the designated decoration area of the recording material. Subsequently, the recording material P is conveyed to the fixing device 30 and undergoes the second fixing process (the first fixing process for the thin line pattern).

In S306, the control unit 60 further conveys the recording material on which the base image and the fine line pattern are formed by the discharge roller pair 20 and the double-sided conveying path 42, and the surface of the recording material on which the base image is formed is fixed again at the fixing nip Nf. It should be the surface (fixing surface) facing the film 31 . The transportation procedure is the same as S104 in the first embodiment. That is, after the trailing edge of the recording material P that has undergone the first fixing process for the thin line pattern passes through the position of the switching guide 40 (FIG. 1), the control unit 60 switches the position of the switching guide 40, and the discharge roller pair 20 reverse rotation. As a result, the recording material P is pulled back into the image forming apparatus and transported to the fixing nip Nf again via the double-sided transport path 42 . At this point, the surface of the recording material P opposite to the surface on which the base image and fine line pattern are formed faces the fixing film 31 . After the recording material P passes through the fixing device 30 , the control unit 60 causes the discharge roller pair 20 to perform reverse conveyance and convey the recording material P to the fixing nip Nf via the double-sided conveying path 42 . As a result, the recording material P reaches the fixing nip Nf again with the surface on which the base image and the fine line pattern are formed facing the fixing film 31 .

In S307, the control unit 60 causes the fixing device 30 to perform additional fixing processing on the surface of the recording material P on which the background image and the fine line pattern are formed. In S308, the recording material P is discharged by the discharge roller pair 20, and the printing job for one recording material P in the decoration mode is completed.

On the other hand, if the setting of the print job is the normal mode in S301, the process proceeds to S309, and the control unit 60 performs normal image formation. In this case, formation of fine line patterns and additional fixing processing are not performed.

As a comparison between Example 1 and the present example, FIG. 13 shows glossiness (gloss value ) and its difference (gloss difference Δ). A solid line indicates Example 1, and a dashed line indicates Example 3. FIG. Here, the fine line width X1 and the fine line spacing X2 are the same value, and the glossiness of the fine line pattern created by changing the values of X1 and X2 (the number of dots of the fine line and the spacing) in the range of 1 dot to 10 dots, And the glossiness of a solid image not forming a fine line pattern was measured.

Comparing Example 3 (broken line) with Example 1 (solid line), although the gloss difference Δ value did not change, the variation range of the gloss value, which was different depending on the values of the width X1 and the interval X2 of the fine lines, was able to be suppressed. I know there is. For example, in Example 3, when the fine line width X1 and the fine line interval X2 are 3 dots, the gloss value measured from the direction of 0° is 58, and when the fine line width X1 and the fine line interval X2 are 5 dots. Since the gloss value measured from the 0° direction is 65, the variation in gloss value is 7. On the other hand, in Example 1, when the fine line width X1 and the fine line interval X2 are 3 dots, the gloss value measured from the direction of 0° is 45, and when the fine line width X1 and the fine line interval X2 are 5 dots. Since the gloss value measured from the 0° direction is 57, the gloss value variation is 12.

The reason why the fluctuation range of the gloss value can be suppressed when the values of the fine line width X1 and the interval X2 are changed is as follows. The flatter the toner surface fixed on the recording material P, the more light is specularly reflected on the surface of the recording material P, and thus the glossiness is higher. In the case of Example 1, when a thin line pattern is formed with thin lines having a width X1 of 2 dots, 3 dots, and 4 dots, the width of the lines is very thin. and the glossiness (gloss value) was low. On the other hand, in Example 3, after the fine line pattern is transferred to the recording material P, the surface on which the fine line pattern is formed is used as the fixing surface, and the fixing process is performed a plurality of times. In other words, after the recording material has passed through the fixing means with the second toner image formed thereon, the control means causes the re-conveying section to convey the recording material to the fixing means again, thereby allowing the fixing means to transfer the second toner image to the recording material. Fix the toner image. As a result, even a very thin line of 2 to 4 dots has an increased flat portion, so that the glossiness of the designated decoration area approaches the glossiness when a relatively wide thin line of 5 dots or more is used.

As described above, according to this embodiment, it is possible to change the level of the decorative effect in which the glossiness changes depending on the direction in which the image is viewed, and to control the change in the absolute value of the glossiness due to the change in the level of the decorative effect. can be suppressed. This widens the range in which the level of the decorative effect of the designated decorative region and the absolute value of the glossiness can be changed according to the user's desires, making it easier to meet the user's needs.

(Other embodiments)
The present invention supplies a program that implements one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by processing to It can also be implemented by a circuit (for example, ASIC) that implements one or more functions.

30... Fixing means/50... Toner image forming means/60... Control means/100, 101... Image forming apparatus

Claims (12)

a toner image forming means for forming a toner image on a recording material;
fixing means for fixing the toner image formed on the recording material by the toner image forming means on the recording material;
control means for controlling the toner image forming means and the fixing means based on image information to form an image on the recording material;
has
The control means causes a first toner image for applying toner to the entire image area to which a decorative effect is to be added, and a second toner image having an anisotropic pattern to overlap on the recording material. and forming the first toner image and the second toner image on the toner image forming means. The image forming apparatus according to claim 1,
The image forming apparatus, wherein the second toner image is formed of a pattern in which parallel lines in the same direction are arranged at predetermined intervals. In the image forming apparatus according to claim 2,
The image forming apparatus, wherein the control means can change the level of the decorative effect by changing the width and interval of parallel lines forming the second toner image. The image forming apparatus according to claim 1,
The second toner image has a first pattern in which parallel lines in a first direction are arranged at a predetermined first interval, and parallel lines in a second direction different from the first direction are arranged at a predetermined second interval. and a second pattern. The image forming apparatus according to claim 1,
The control means selectively uses, as the second toner image, a plurality of patterns each formed of parallel lines extending in the same direction and having parallel lines extending in different directions. Image forming device. The image forming apparatus according to any one of claims 1 to 5,
The image forming apparatus, wherein the first toner image is an image in which toner is applied in a uniform thickness over the entire image area to which the decorative effect is to be added. The image forming apparatus according to any one of claims 1 to 6,
The image forming apparatus, wherein the first toner image and the second toner image are toner images using toner of the same color. The image forming apparatus according to claim 1,
The control means controls the first mode in which the toner image forming means forms the first toner image and the second toner image, and the control means controls the image information without causing the toner image forming means to form the second toner image. and a second mode for forming a corresponding toner image. The image forming apparatus according to any one of claims 1 to 8,
further comprising a re-conveying unit for conveying the recording material that has passed through the fixing unit to the toner image forming unit again;
The control means forms the first toner image on the recording material by the toner image forming means, fixes the first toner image on the recording material by the fixing means, and then causes the re-conveyance section to perform the recording. The recording material is conveyed again to the toner image forming means, the second toner image is formed on the recording material by the toner image forming means, and the second toner image is fixed on the recording material by the fixing means. image forming apparatus. The image forming apparatus according to claim 9,
After the second toner image is fixed on the recording material by the fixing means, the control means causes the re-conveying section to convey the recording material to the fixing means again, and the second toner image is further conveyed by the fixing means. An image forming apparatus characterized by fixing an image. The image forming apparatus according to any one of claims 1 to 8,
The toner image forming means includes a first image carrier that carries a toner image, a second image carrier that carries a toner image, and toner from the first image carrier and the second image carrier onto the recording material. a transfer means for transferring the image;
The control means causes the toner image forming means to form the first toner image on the first image carrier, forms the second toner image on the second image carrier, and causes the transfer means to form the recording material. and fixing the first toner image and the second toner image on the recording material by the fixing means after the first toner image and the second toner image are transferred to the recording medium. The fixing means includes a cylindrical film, a nip forming member having a heating element for heating the film and disposed inside the film, and a pressure member in pressure contact with the nip forming member with the film interposed therebetween. and a nip portion formed between the nip forming member and the pressure member, while the recording material is sandwiched and conveyed between the film and the pressure member, and is conveyed on the recording material. heat the image,
The image forming apparatus according to any one of claims 1 to 11, characterized by:

Images