Image forming system

Abstract

Even if there are differences in the amount of charge on each part of the recording medium, static electricity is removed more uniformly. [Solution] The image forming system 100 for forming an electrophotographic image comprises an image forming unit 13a for forming an image on a recording medium 110, a transport path 18 for transporting the recording medium 110, and a plurality of static elimination units 32 arranged in a direction intersecting the transport direction of the recording medium 110, which de-charge the recording medium 110 according to the image density of the recording medium 110 that has been charged by image forming and / or transport. The image forming system 100 includes a fixing unit 13b downstream of the image forming unit 13a, and the static elimination units 32 are arranged downstream of the fixing unit 13b on the transport path 18.

Description

Technical Field

[0001] The present invention relates to an image forming system.

Background Art

[0002] Conventionally, in an image forming system, as a technique for removing static electricity of a recording medium during conveyance, for example, there is a technique described in Patent Document 1. The technique described in Patent Document 1 uniformly removes static electricity of the recording medium in the width direction with static eliminator needles arranged in a plurality in the width direction of the recording medium during conveyance.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, as will be described below, the conventional technique described in Patent Document 1 may cause the stacked recording media to stick to each other due to static electricity, making it difficult to align the end faces.

[0005] The prior art described in Patent Document 1 uniformly removes static electricity from the recording medium in the width direction during transport. However, the amount of static electricity charged on the recording medium differs in each part due to differences in image density formed on the recording medium. Therefore, even if the recording medium is uniformly removed in the width direction during transport, as in the prior art described in Patent Document 1, the recording medium cannot be uniformly removed, and residual static electricity remains in each part of the recording medium. When residual static electricity remains in each part of the recording medium, the stacked recording media stick together due to static electricity. Therefore, the prior art described in Patent Document 1 makes it difficult to align the edges of the stacked recording media. In other words, the prior art described in Patent Document 1 causes a phenomenon where the edges of the stacked recording media cannot be aligned even if strong force is applied.

[0006] This invention has been made in view of the problems of the prior art described above, and the object of this invention is to provide an image forming system that can remove static electricity more uniformly even if there are differences in the amount of charge in each part of the recording medium. [Means for solving the problem]

[0007] The above-mentioned problems of the present invention are solved by the following means.

[0008] (1) An image forming system for forming an electrophotographic image, comprising: an image forming unit for forming an image on a recording medium; a transport path for transporting the recording medium; and a plurality of static discharge units arranged in a direction intersecting the transport direction of the recording medium, which discharge the recording medium by applying an electric charge according to the image density of the recording medium that has been charged by image forming and / or transport.

[0009] (2) The image forming system according to (1) above, wherein the image forming unit is located downstream of the image forming unit and comprises a fixing unit for fixing an image onto a recording medium, and the static elimination unit is located downstream of the fixing unit on the transport path.

[0010] (3) The image forming system according to (1) above, comprising a recording medium loading device for loading the recording medium after printing, wherein the static elimination unit is located upstream of the recording medium loading device.

[0011] (4) The image forming system according to (1) above, wherein the static elimination unit is positioned so as not to come into contact with the recording medium.

[0012] (5) The image forming system according to (1) above, wherein the static elimination unit is positioned so as not to protrude from the guide surface that guides the recording medium.

[0013] (6) The image forming system according to (1) above, further comprising a guide section for transporting the recording medium, wherein the guide section is provided with an opening for passing electric charge generated from the static elimination section toward the recording medium.

[0014] (7) The image forming system according to (1) above, wherein the static elimination unit is a needle-shaped electrode.

[0015] (8) The image forming system according to (1) above, comprising a control unit that controls the amount of charge applied based on the image density.

[0016] (9) The image forming system according to (1) above, further comprising an output-adjustable power supply unit that applies charge to each of the static elimination units.

[0017] (10) The image forming system according to (1) above, comprising: an image density detection unit for detecting the image density on a recording medium; and a control unit for controlling the amount of charge applied based on the result detected by the image density detection unit.

[0018] (11) The image forming system according to (1) above, wherein the static elimination unit applies charge to each adjacent recording medium in the recording medium stacking direction such that the faces of each other have the same polarity.

[0019] (12) The charge removing unit is the image forming system according to (11) above, which applies charges so that the absolute values of the amounts of charge on the surfaces of adjacent recording media facing each other in the recording medium stacking direction are equal.

[0020] (13) The charge removing unit is the image forming system according to (11) above, which switches the amount of charge applied for each recording medium.

[0021] (14) The charge removing unit is the image forming system according to (11) above, in which the amount of charge to be applied can be specified manually.

[0022] (15) The charge removing unit is the image forming system according to (1) above, which is disposed on both sides of the conveyance path.

[0023] (16) The image forming system according to (15) above, which includes image density detection units on both sides of the conveyance path.

[0024] (17) The image forming system according to (15) above, which includes surface potential meters on both sides of the conveyance path.

[0025] (18) The charge removing unit is the image forming system according to (1) above, which is arranged in a plurality of rows in the conveyance direction of the recording medium.

[0026] (19) The charge removing unit is composed of needle electrodes, and the needle electrodes are arranged in a plurality of rows at positions with different phases in a direction intersecting the conveyance direction of the recording medium. The image forming system according to (18) above.

[0027] (20) The image forming system according to (1) above, which includes a recording medium position detection unit for detecting the position of the recording medium, and a control unit for controlling the timing of applying charges based on the result detected by the recording medium position detection unit.

[0028] (21) The image forming system according to (1) above, which includes a charge amount detection unit for detecting the amount of charge of the recording medium, and a control unit for controlling the amount of charge applied based on the result detected by the charge amount detection unit.

[0029] (22) The image forming system according to (1) above, comprising a humidity detection unit for detecting humidity and a control unit for controlling the amount of charge applied based on the result detected by the humidity detection unit.

[0030] (23) The image forming system according to (1) above, wherein the static elimination unit reduces the amount of charge applied to the front surface compared to the back surface.

[0031] (24) The image forming system according to (1) above, wherein the static elimination unit applies more charge as the image density increases.

[0032] (25) The image forming system according to (1) above, wherein the static elimination unit applies a larger amount of charge as the recording medium transport speed increases.

[0033] (26) The image forming system according to (1) above, wherein another static elimination unit is provided upstream of the static elimination unit, the static elimination unit is composed of needle-shaped electrodes, and the other static elimination unit is composed of static elimination contact members. [Effects of the Invention]

[0034] According to the present invention, even if there are differences in the amount of charge in each part of the recording medium, static electricity can be removed more uniformly. [Brief explanation of the drawing]

[0035] [Figure 1] This is a front view of the image forming system according to the embodiment. [Figure 2] This is a functional block diagram of the static elimination device for the image forming system according to the embodiment. [Figure 3] This is a diagram illustrating the operation of the static elimination device. [Figure 4] This is a diagram showing the configuration of the static elimination device as viewed from the upstream side of the recording medium transport. [Figure 5] This is a diagram showing the configuration of the static elimination device as viewed from the side of the recording medium transport. [Figure 6] This is an external view of the static elimination section (needle-shaped electrode) of the static elimination device. [Figure 7] This is a schematic diagram of the static elimination section (needle-shaped electrodes) of the static elimination device as seen from above. [Figure 8] This is a schematic diagram showing the state of each stacked recording medium after charge application. [Figure 9] This is an explanatory diagram of the front and back sides of a recording medium. [Figure 10] This graph shows the relationship between image density and the amount of charge added. [Figure 11] This graph shows the relationship between the recording medium transport speed and the amount of charge added. [Figure 12] This is a flowchart showing the operation of the static elimination device according to the embodiment. [Modes for carrying out the invention]

[0036] Embodiments of the present invention will be described in detail below with reference to the drawings. Note that the drawings are merely schematic representations to allow for a thorough understanding of the present invention. Therefore, the present invention is not limited to the illustrated examples. Furthermore, in each drawing, common or similar components are denoted by the same reference numerals, and their redundant descriptions are omitted.

[0037] <Overall configuration of the image forming system> The overall configuration of the image forming system 100 according to this embodiment will be described below with reference to Figure 1. Figure 1 is a front view of the image forming system 100 according to this embodiment. In the following description, "upstream" and "downstream" are based on the transport direction of the recording medium.

[0038] As shown in Figure 1, the image forming system 100 according to this embodiment includes an operation unit 11, and, from upstream to downstream, a paper feeder 12, an image forming apparatus 13, an improper recording medium loading device 14, a recording medium loading device 15, and an output unit 17. The image forming system 100 forms an electrophotographic image on a recording medium such as paper. The recording medium is not limited to paper, but may be, for example, an OHP sheet or a cloth.

[0039] The control unit 11 is a device that receives user input. The paper feeder 12 is a device that supplies a recording medium to the image forming apparatus 13. The image forming apparatus 13 is an apparatus for forming an image on a recording medium. The improper recording medium loading device 14 is a device in which an improper recording medium is loaded. The recording medium loading device 15 is a device that loads appropriate recording media into its interior. The discharge unit 17 is a component from which the recording medium is discharged.

[0040] In this embodiment, the image forming apparatus 13 is configured as an electrophotographic printer that forms an electrophotographic image on a recording medium. The image forming apparatus 13 includes an image forming unit 13a, a fixing unit 13b, a transport unit 13c, and a control unit 13d.

[0041] The image forming unit 13a is a component that forms an electrophotographic image on a recording medium. The fixing unit 13b is a component that heats and pressurizes the recording medium to fix the electrophotographic image onto the recording medium. The fixing unit 13b is located downstream of the image forming unit 13a in the transport path. The transport unit 13c is a component that transports the recording medium. The control unit 13d is a component that controls the operation of the image forming apparatus 13. The control unit 13d is composed of a microcomputer or the like.

[0042] In this embodiment, the improper recording medium stacking device 14 includes a first improper recording medium stacking device 14a, a second improper recording medium stacking device 14b, and a third improper recording medium stacking device 14c, which stack improper recording mediums or perform arbitrary processing on the improper recording mediums. Here, "improper recording medium" means a recording medium in an improper state. "Improper state" means a state in which image formation defects are detected or the improper recording medium has a strong curl. "Arbitrary processing" refers to processing such as forming punch holes in the improper recording medium or forcing the curl on the improper recording medium to disappear.

[0043] In this embodiment, the recording medium stacking device 15 has a first recording medium stacking device 15a and a second recording medium stacking device 15b, on which arbitrarily specified types of recording media are stacked. Inside the first recording medium stacking device 15a, there is a trolley 16 for transporting the recording media stored and stacked inside the first recording medium stacking device 15a to the outside. Inside the second recording medium stacking device 15b, there is a stapling mechanism (stapler mechanism) (not shown) for fixing multiple recording media. The image forming system 100 discharges the arbitrary type of recording media and the multiple recording media fixed by the stapling mechanism of the second recording medium stacking device 15b to the discharge unit 17.

[0044] Furthermore, the image forming system 100 is equipped with a transport path 18 that transports the recording medium from the paper feeder 12 to the discharge unit 17. The recording medium is transported from the paper feeder 12 to the discharge unit 17 via the transport path 18. The recording medium becomes charged when an image is formed in the image forming apparatus 13. In addition, the recording medium becomes charged due to friction as it is transported along the transport path 18. When the recording medium becomes charged, the recording mediums stacked in the recording medium stacking device 15 and the discharge unit 17 tend to stick together due to static electricity, making it difficult to align their edges.

[0045] Furthermore, inside the image forming system 100, a static elimination device 21 is provided between the fixing unit 13b and the first improper recording medium loading device 14a to uniformly eliminate static electricity from the entire recording medium. The static elimination device 21 has a static elimination contact member 22 that contacts the recording medium to eliminate static electricity from it. The static elimination contact member 22 is composed of, for example, a static elimination roller.

[0046] Furthermore, within the image forming system 100, a static elimination device 31a is provided between 14c and 15a, and a static elimination device 31b is provided between 15a and 15b. The static elimination devices 31a and 31b are components that partially eliminate static electricity from the recording medium. Hereinafter, the static elimination devices 31a and 31b will be collectively referred to as "static elimination device 31". The static elimination device 31 has a static elimination section 32. As shown in Figure 6, the static elimination section 32 is composed of needle-shaped electrodes.

[0047] The image forming system 100 includes a static elimination device 21 that uniformly eliminates static electricity from the entire recording medium and a static elimination device 31 that partially eliminates static electricity from the recording medium. In such an image forming system 100, the static elimination device 21 can completely eliminate static electricity from the recording medium, and the static elimination device 31 can partially eliminate static electricity from each part of the recording medium. Therefore, the image forming system 100 can accurately and effectively (uniformly) eliminate static electricity from each part of the recording medium.

[0048] <Overview of the configuration and operation of the static elimination device> The image forming system 100 according to this embodiment has its main features in the configuration of the static elimination device 31. The configuration and operation of the static elimination device 31 will be described below with reference to Figures 2 to 7. Figure 2 is a functional block diagram of the static elimination device 31 of the image forming system 100. Figure 3 is an explanatory diagram of the operation of the static elimination device 31. Figure 4 is a configuration diagram of the static elimination device 31 viewed from the upstream side of the recording medium transport. Figure 5 is a configuration diagram of the static elimination device 31 viewed from the side of the recording medium transport. Figure 6 is an external view of the static elimination section 32 (needle-shaped electrode) of the static elimination device 31. Figure 7 is a schematic arrangement diagram of the static elimination section 32 (needle-shaped electrode) of the static elimination device 31 viewed from above.

[0049] As shown in Figure 2, the static elimination device 31 includes a static elimination unit 32, a control unit 33, a power supply unit 34, a post-processing unit 35, and a transport unit 36. Multiple static elimination units 32 are arranged in a direction intersecting the transport direction of the recording medium, and the recording medium is statically eliminated by applying an electric charge according to the image density of the recording medium that has been charged by image formation and / or transport.

[0050] The static elimination unit 32 is a charge application unit that applies charge to the recording medium. The static elimination unit 32 (charge application unit) eliminates static charge from the recording medium by applying charge to the recording medium according to the image density of the recording medium that has been charged by image formation and / or transport. The control unit 33 is a component that controls the operation of the static elimination device 31. The control unit 33 is composed of a microcomputer or the like. The power supply unit 34 is a component that supplies power to each part. The power supply unit 34 has an output adjustable configuration that applies charge to each static elimination unit 32. The post-processing unit 35 is a component that performs arbitrary post-processing on the recording medium. The transport unit 36 ​​is a component that transports the recording medium.

[0051] The static elimination unit 32 includes an image density detection unit 41, a surface potential meter 42, a recording medium position detection unit 43, a charge amount detection unit 44, a humidity detection unit 45, and a transport speed detection unit 46.

[0052] The image density detection unit 41 is a component that detects the image density of each part of the recording medium. The surface potential meter 42 is a component that measures the surface potential of each part of the recording medium. The surface potential meter 42 is provided on both sides of the transport path 18. The recording medium position detection unit 43 is a component that detects the position of the recording medium (particularly the leading edge position of the recording medium). The charge detection unit 44 is a component that detects the amount of charge in each part of the recording medium. The humidity detection unit 45 is a component that detects humidity. The transport speed detection unit 46 is a component that detects the transport speed of the recording medium.

[0053] The recording medium is negatively charged in areas with higher image density. Therefore, the static elimination device 31 applies a positive charge to each part of the recording medium according to the image density of that part. As a result, the image forming system 100 can accurately and effectively (uniformly) eliminate static electricity from each part of the recording medium.

[0054] Figure 3 shows an overview of the operation of the static elimination device 31. Although Figure 3 schematically shows the static elimination unit 32, the static elimination unit 32 has the configuration shown in Figure 6. As shown in Figure 3, the static elimination device 31 has multiple static elimination units 32 arranged in an intersecting direction 122 that intersects with the transport direction 121 of the recording medium 110. The control unit 33 (Figure 2) of the static elimination device 31 uses an arbitrarily set threshold as a reference and turns ON the static elimination unit 32 facing the portion 131a where the image density 131 is darker than the threshold, and turns OFF the static elimination unit 32 facing the portion 131b where the image density 131 is lighter than the threshold. As a result, the static elimination device 31 applies an amount of charge to each part of the recording medium 110 according to the image density formed on each part of the recording medium 110 using the static elimination units 32.

[0055] Figures 4 and 5 show the specific configuration of the static elimination device 31. Although Figures 4 and 5 schematically show the static elimination unit 32, the static elimination unit 32 has the configuration shown in Figure 6. As shown in Figures 4 and 5, the static elimination device 31 includes a guide unit 51 that guides the transport of the recording medium 110 (Figure 3) transported by the transport path 18. The guide unit 51 has an upper guide unit 51a located above the transport path 18 and a lower guide unit 51b located below the transport path 18. A gap is provided between the upper guide unit 51a and the lower guide unit 51b, which constitutes the transport path 18. As shown in Figure 4, the upper guide unit 51a and the lower guide unit 51b are formed as wide block units at their end portions in the width direction, and as narrow plate-like units (rib units) in the middle portions in the width direction.

[0056] As shown in Figure 5, the upper guide section 51a and the lower guide section 51b are configured such that the recording medium 110 passes between them from the inlet side to the outlet side, with the right side of Figure 5 being the inlet side and the left side being the outlet side. An image density detection unit 41, a surface potential meter 42, a recording medium position detection unit 43, a charge quantity detection unit 44, a humidity detection unit 45, and a transport speed detection unit 46 are located on the front side (right side in Figure 5) of the upper guide section 51a and the lower guide section 51b. The inlets of the upper guide section 51a and the lower guide section 51b are formed by inclined surfaces that are tilted in the vertical direction, and the distance between them decreases from the front side to the back side. The outlets of the upper guide section 51a and the lower guide section 51b are formed by flat surfaces that are cut in the vertical direction. Furthermore, the portions of the upper guide section 51a and the lower guide section 51b from the entrance to the exit are formed by flat guide surfaces 52 that are cut in the direction of transport, and the distance between them is equal from the entrance side to the exit side.

[0057] A static elimination unit 32 is located in the upper guide section 51a from the inlet to the outlet. As shown in Figure 4, the static elimination unit 32 is provided between the plate-like sections (rib sections) of the upper guide section 51a. Returning to Figure 5, similarly, a static elimination unit 32 is also located in the lower guide section 51b from the inlet to the outlet. As shown in Figure 4, the static elimination unit 32 is provided between the plate-like sections (rib sections) of the lower guide section 51b.

[0058] Furthermore, as shown in Figure 5, an opening 53 is provided between the upper guide portion 51a and the lower guide portion 51b for the passage of charge generated from the static elimination portion 32 toward the recording medium 110. As shown in Figure 4, the opening 53 is provided between the plate-like portion (rib portion) and the plate-like portion (rib portion) in the upper guide portion 51a and the lower guide portion 51b.

[0059] The static elimination unit 32 is preferably positioned so as not to come into contact with the recording medium 110. In the example shown in Figures 4 and 5, the image forming system 100 includes a guide unit 51 that guides the transport of the recording medium 110. An opening 53 is provided in the guide unit 51 for the charge generated from the static elimination unit 32 toward the recording medium 110 to pass through. Furthermore, the static elimination unit 32 is positioned so as not to protrude from the guide surface 52 that guides the recording medium 110.

[0060] As shown in Figure 6, the static elimination unit 32 is composed of needle-shaped electrodes. As shown in Figure 7, it is preferable that the static elimination units 32 be arranged in multiple rows in the transport direction 121 of the recording medium 110. Also, as shown in Figure 7, it is preferable that the static elimination units 32 be arranged in multiple rows at different phase positions in the intersecting direction 122 that intersects the transport direction 121 of the recording medium 110. In other words, it is preferable that each static elimination unit 32 be arranged in a staggered pattern. This allows the image forming system 100 to arrange each static elimination unit 32 at high density, so that each part of the recording medium 110 can be statically eliminated accurately and effectively (uniformly).

[0061] Furthermore, in the image forming system 100, the static elimination unit 32 of the static elimination device 31 is composed of needle-shaped electrodes. Because the needle-shaped electrodes can be arranged at high density, static elimination can be performed corresponding to each pixel of the image formed on the recording medium 110. In addition, the needle-shaped electrodes can impart charge to the recording medium 110 with low output. Moreover, because needle-shaped electrodes are relatively inexpensive and highly durable, cost reduction and improved durability of the static elimination unit 32 can be achieved. However, the performance of the needle-shaped electrodes may deteriorate if dirt adheres to the needle tips or if the needle tips wear down. However, the image forming system 100 has openings 53 in the upper guide section 51a and the lower guide section 51b, and positions the needle tips of the static elimination unit 32 (needle-shaped electrodes) so that they do not protrude from the guide surface 52. As a result, the image forming system 100 can suppress the adhesion of dirt to the needle tips of the needle-shaped electrodes. In addition, the image forming system 100 can suppress the wear of the needle tips of the needle electrodes due to contact with the recording medium 110.

[0062] <Charge applied to the recording medium> The following explanation will describe the charge applied to the recording medium 110 with reference to Figures 8 to 11. Figure 8 is a schematic diagram showing the state of each stacked recording medium 110 after charge application. Figure 9 is an explanatory diagram of the front and back surfaces of the recording medium 110. Figure 10 is a graph showing the relationship between image density and the amount of charge applied. Figure 11 is a graph showing the relationship between the recording medium transport speed and the amount of charge applied.

[0063] As shown in Figure 8, the static elimination unit 32 is preferable to apply charge to each adjacent recording medium 110 in the recording medium stacking direction (in the example shown in Figure 8, the first recording medium 110a that is stacked first and the second recording medium 110b that is stacked later) so that the opposing surfaces have the same polarity. This makes it easier for the image forming system 100 to separate the recording mediums 110 from each other. Therefore, the image forming system 100 can suppress the phenomenon in which the recording mediums 110 stacked on the recording medium stacking device 15 or the discharge unit 17 stick together due to static electricity, making it difficult to align their end faces. In other words, the image forming system 100 can suppress the phenomenon in which it is not possible to align the end faces of the stacked recording mediums 110 even if strong force is applied.

[0064] Furthermore, the static elimination unit 32 may be configured to apply charge to adjacent recording media 110 in the recording media stacking direction such that the absolute values ​​of the charge amounts on the opposing surfaces are equal. This allows the image forming system 100 to reduce the force of static electricity causing the recording media 110 stacked on the recording media stacking device 15 and the discharge unit 17 to stick together.

[0065] Furthermore, the static elimination unit 32 may be configured to switch the amount of charge applied for each recording medium 110. This allows the image forming system 100 to finely adjust the reduction of the force that causes the recording media 110 stacked on the recording medium loading device 15 and the discharge unit 17 to stick together due to static electricity.

[0066] Furthermore, the static elimination unit 32 may be configured to apply less charge to the front surface 111 (Figure 9) of the recording medium 110 than to the back surface 112 (Figure 9) when performing double-sided printing. In other words, the static elimination unit 32 may be configured to apply more charge to the back surface 112 (Figure 9) of the recording medium 110 than to the front surface 111 (Figure 9). Figure 9 shows the recording medium 110 being transported with the front surface 111 facing downwards and the back surface 112 facing upwards. Since the image is formed on the back surface 112 (Figure 9) of the recording medium 110 later than on the front surface 111 (Figure 9), the effects of static electricity tend to remain on the back surface 112 (Figure 9) more than on the front surface 111 (Figure 9). Taking this into consideration, the image forming system 100 can reduce the effects of static electricity more easily by applying more charge to the back surface 112 (Figure 9) of the recording medium 110 than to the front surface 111 (Figure 9). This also allows the image forming system 100 to reduce the force that causes the recording media 110 stacked on the recording media loading device 15 and the discharge unit 17 to stick together due to static electricity.

[0067] Furthermore, as shown in Figure 10, the static elimination unit 32 may be configured to apply more charge as the image density increases. This also allows the image forming system 100 to efficiently reduce the static-induced sticking force between the recording media 110 stacked on the recording media loading device 15 and the discharge unit 17.

[0068] Furthermore, as shown in Figure 11, the static elimination unit 32 may be configured to apply more charge as the recording medium transport speed increases. This also allows the image forming system 100 to efficiently reduce the static-induced sticking force between the recording media 110 stacked on the recording medium loading device 15 and the discharge unit 17.

[0069] <Operation of the static eliminator> The operation of the static elimination device 31 will be explained below with reference to Figure 12. Figure 12 is a flowchart showing the operation of the static elimination device 31.

[0070] As shown in Figure 12, when the recording media 110 are transported from the image forming apparatus 13, the static elimination device 31 detects the position of each recording media 110 with the recording media position detection unit 43, and further detects the image density of each recording media 110 with the image density detection unit 41 (step S105).

[0071] After step S105, the control unit 33 of the static elimination device 31 determines the amount of charge to be applied to each part of the recording medium 110 based on the results detected by the image density detection unit 41 (step S110). The amount of charge to be applied is predetermined according to the image density formed on each part of the recording medium 110.

[0072] After step S110, the static elimination device 31 applies an amount of charge corresponding to the image density to each part of the recording medium 110 in the static elimination unit 32 (step S115).

[0073] After step S115, the control unit 33 of the static elimination device 31 determines whether or not it has detected the last end of the recording medium 110 (step S120).

[0074] If the determination in step S120 is that the last end of the recording medium 110 has not been detected ("No"), the process returns to step S105. On the other hand, if the determination in step S120 is that the last end of the recording medium 110 has been detected ("Yes"), the control unit 33 terminates processing for the current recording medium 110 and performs the same processing for the next recording medium 110. The control unit 33 repeats the series of routine processes until there are no more recording mediums 110 (i.e., image-formed (printed) recording mediums 110) being transported along the transport path 18, and terminates the series of routine processes when there are no more recording mediums 110 being transported along the transport path 18.

[0075] In such an image forming system 100, the control unit 33 of the static elimination device 31 communicates with the control unit 13d of the image forming apparatus 13 to acquire information about the image formed on the recording medium 110 (for example, image formation position information and image density information). The control unit 33 controls the amount of charge applied to each part of the recording medium 110 based on the results detected by the image density detection unit 41. In other words, the control unit 33 controls the amount of charge applied to each part of the recording medium 110 based on the image density formed on the recording medium 110. The control unit 33 can also control the amount of charge applied to each part of the recording medium 110 based on the results detected by the surface potential meter 42. Furthermore, the control unit 33 controls the timing of charge application based on the results detected by the recording medium position detection unit 43. In addition, the control unit 33 can also control the amount of charge applied to each part of the recording medium 110 based on the results detected by the humidity detection unit 45.

[0076] <Main features of the image forming system> The image forming system 100 according to this embodiment can be configured to have the following features.

[0077] (1) As shown in Figure 1, the image forming system 100 according to this embodiment is an image forming system that forms an electrophotographic image. The image forming system 100 comprises an image forming unit 13a, a transport path 18, and a static elimination unit 32. The image forming unit 13a is a component that forms an image on the recording medium 110. The transport path 18 is a component that transports the recording medium 110. The static elimination unit 32 is a component that eliminates static charge from the recording medium 110. Multiple static elimination units 32 are arranged in a direction intersecting the transport direction of the recording medium 110. The static elimination unit 32 applies charge to each part of the recording medium 110 according to the image density of the recording medium 110 that has been charged by image forming and / or transport.

[0078] The image forming system 100 according to this embodiment applies individual charges to the recording medium 110 according to the image density of the recording medium 110 using a plurality of static elimination units 32 arranged in a direction intersecting the transport direction of the recording medium 110. As a result, even if the image density differs in different parts of the recording medium 110, the image forming system 100 can effectively (uniformly) remove static electricity from each part of the recording medium 110 using the static elimination units 32. Such an image forming system 100 can reduce residual static electricity in each part of the recording medium 110. Therefore, the image forming system 100 can suppress the occurrence of the phenomenon in the conventional technology described in Patent Document 1, in which stacked recording mediums 110 stick together due to static electricity, making it difficult to align the edges. In other words, unlike the conventional technology described in Patent Document 1, the image forming system 100 can suppress the occurrence of the phenomenon in which the edges of stacked recording mediums 110 cannot be aligned even when strong force is applied.

[0079] (2) As shown in Figure 1, the image forming system 100 described in item (1) above includes a fixing unit 13b which is located downstream of the image forming unit 13a and fixes the image onto the recording medium 110. The static elimination unit 32 is preferably located downstream of the fixing unit 13b on the transport path 18.

[0080] In this embodiment of the image forming system 100, the static elimination unit 32 can effectively (uniformly) eliminate static electricity from each part of the recording medium 110 on which the image has been fixed by the fixing unit 13b.

[0081] (3) As shown in Figure 1, the image forming system 100 described in item (1) above may be configured to include a recording medium loading device 15 for loading the recording medium 110 after image formation (after printing). The static elimination unit 32 is preferably located upstream of the recording medium loading device 15.

[0082] In this embodiment of the image forming system 100, the static elimination unit 32 can effectively (uniformly) remove static electricity from each part of the recording medium 110 before it is stacked in the recording medium stacking device 15. This image forming system 100 can suppress the phenomenon in which the stacked recording mediums 110 stick together due to static electricity, making it difficult to align their edges.

[0083] (4) As shown in Figures 4 and 5, in the image forming system 100 of item (1) above, it is preferable that the static elimination unit 32 is positioned so as not to come into contact with the recording medium 110.

[0084] The image forming system 100 according to this embodiment can stabilize the operation of the static elimination unit 32. Therefore, the image forming system 100 can stably and effectively (uniformly) eliminate static electricity from each part of the recording medium 110 using the static elimination unit 32.

[0085] (5) As shown in Figures 4 and 5, in the image forming system 100 of item (1) above, it is preferable that the static elimination unit 32 (needle-shaped electrode) is positioned so as not to protrude from the guide surface 52 that guides the recording medium 110.

[0086] The image forming system 100 according to this embodiment can suppress the adhesion of dirt to the needle tip of the static elimination unit 32 (needle-shaped electrode). Furthermore, the image forming system 100 can suppress the wear of the needle tip of the static elimination unit 32 (needle-shaped electrode) due to contact with the recording medium 110.

[0087] (6) As shown in Figures 4 and 5, the image forming system 100 described in item (1) above includes a guide section 51 that guides the transport of the recording medium 110. It is preferable that the guide section 51 has an opening 53 for passing the charge generated from the static elimination section 32 toward the recording medium 110.

[0088] The image forming system 100 according to this embodiment can suppress the adhesion of dirt to the needle tip of the static elimination unit 32 (needle-shaped electrode). Furthermore, the image forming system 100 can suppress the wear of the needle tip of the static elimination unit 32 (needle-shaped electrode) due to contact with the recording medium 110.

[0089] (7) As shown in Figure 6, in the image forming system 100 of item (1) above, the static elimination unit 32 can be made up of needle-shaped electrodes.

[0090] In this embodiment of the image forming system 100, static elimination units 32, each composed of needle-shaped electrodes, can eliminate static electricity for each element of the image formed on the recording medium 110. Therefore, the image forming system 100 can effectively (uniformly) eliminate static electricity from each part of the recording medium 110.

[0091] (8) As shown in Figure 2, the image forming system 100 described in item (1) above may be configured to include a control unit 33 that controls the amount of charge applied based on the image density. However, instead of the control unit 33, the control unit 13d or the overall control unit 99 may control the amount of charge applied based on the image density (the same applies hereinafter).

[0092] The image forming system 100 according to this embodiment can effectively (uniformly) remove static electricity from each part of the recording medium 110.

[0093] (9) As shown in Figure 2, the image forming system 100 described in item (1) above may be configured to include an output-adjustable power supply unit 34 that applies charge to each static elimination unit 32.

[0094] In this embodiment of the image forming system 100, the output of charge application can be adjusted for each static elimination unit 32.

[0095] (10) As shown in Figure 2, the image forming system 100 in item (1) above may be configured to include an image density detection unit 41 that detects the image density on the recording medium 110, and a control unit 33 that controls the amount of charge applied based on the result detected by the image density detection unit 41.

[0096] In this embodiment of the image forming system 100, by controlling the amount of charge applied based on the results detected by the image density detection unit 41, static electricity can be effectively (uniformly) removed from each part of the recording medium 110.

[0097] (11) As shown in Figure 8, in the image forming system 100 of item (1) above, the static elimination unit 32 may be configured to apply charge to each adjacent recording medium 110 in the recording medium stacking direction such that the faces of each other have the same polarity.

[0098] The image forming system 100 according to this embodiment makes it easier to separate the stacked recording media 110 from each other. Therefore, the image forming system 100 can suppress the phenomenon in which the recording media 110 stacked on the recording media stacking device 15 or the discharge unit 17 stick together due to static electricity, making it difficult to align their edges. In other words, the image forming system 100 can suppress the phenomenon in which the edges of the stacked recording media 110 cannot be aligned even if strong force is applied.

[0099] (12) In the image forming system 100 described in item (11) above, the static elimination unit 32 may be configured to apply charge to each recording medium 110 such that the absolute values ​​of the charge amounts on the surfaces facing each other are equal.

[0100] The image forming system 100 according to this embodiment can reduce the force of electrostatic adhesion between recording media 110 stacked on the recording media loading device 15 and the discharge unit 17.

[0101] (13) In the image forming system 100 described in item (11) above, the static elimination unit 32 may be configured to switch the amount of charge applied for each recording medium 110.

[0102] In this embodiment of the image forming system 100, the amount of charge applied to each recording medium 110 can be switched to finely adjust the reduction of the electrostatic force that causes the recording media 110 stacked on the recording medium loading device 15 and the discharge unit 17 to stick together.

[0103] (14) In the image forming system 100 described in item (11) above, the static elimination unit 32 may be configured to allow manual specification of the amount of charge to be applied.

[0104] In this embodiment of the image forming system 100, the amount of charge to be applied can be manually specified by the user.

[0105] (15) As shown in Figures 4 and 5, in the image forming system 100 of item (1) above, the static elimination unit 32 is preferably arranged on both sides of the transport path 18.

[0106] The image forming system 100 according to this embodiment can apply an electric charge to the front surface 111 and the back surface 112 of the recording medium 110, thereby removing static electricity from both sides of the recording medium 110.

[0107] (16) The image forming system 100 described in item (15) above may be configured to include image density detection units 41 on both sides of the transport path 18.

[0108] In this embodiment of the image forming system 100, static electricity can be removed from each part of the recording medium 110 independently on both sides of the recording medium 110, according to the image density of the image formed on each part of both sides of the recording medium 110.

[0109] (17) The image forming system 100 described in item (15) above may be configured to include surface potential meters 42 on both sides of the transport path 18.

[0110] In this embodiment of the image forming system 100, static electricity can be removed from each part of the recording medium 110 independently on both sides, depending on the surface potential of both sides of the recording medium 110.

[0111] (18) As shown in Figures 6 and 7, in the image forming system 100 of item (1) above, the static elimination unit 32 is preferably arranged in multiple rows in the transport direction 121 of the recording medium 110.

[0112] In this embodiment of the image forming system 100, since the static elimination units 32 can be arranged at high density, static elimination can be performed accurately and effectively (uniformly) on each part of the recording medium 110.

[0113] (19) As shown in Figures 6 and 7, in the image forming system 100 of item (18) above, the static elimination unit 32 can be made up of needle-shaped electrodes. The needle-shaped electrodes are preferably arranged in multiple rows at positions with different phases in the intersecting direction 122 that intersects with the transport direction 121 of the recording medium 110.

[0114] In this embodiment of the image forming system 100, since the static elimination units 32 can be arranged at a higher density, static elimination can be performed more accurately and effectively (uniformly) on each part of the recording medium 110.

[0115] (20) As shown in Figure 2, the image forming system 100 in item (1) above may be configured to include a recording medium position detection unit 43 that detects the position of the recording medium 110, and a control unit 33 that controls the timing of applying charge based on the result detected by the recording medium position detection unit 43.

[0116] In this embodiment of the image forming system 100, the timing of applying charge can be controlled based on the results detected by the recording medium position detection unit 43, thus enabling efficient static discharge.

[0117] (21) As shown in Figure 2, the image forming system 100 in item (1) above may be configured to include a charge amount detection unit 44 that detects the amount of charge of the recording medium 110, and a control unit 33 that controls the amount of charge applied based on the results detected by the charge amount detection unit 44.

[0118] The image forming system 100 according to this embodiment can control the amount of charge applied based on the results detected by the charge amount detection unit 44.

[0119] (22) As shown in Figure 2, the image forming system 100 in item (1) above may be configured to include a humidity detection unit 45 for detecting humidity and a control unit 33 for controlling the amount of charge applied based on the result detected by the humidity detection unit 45.

[0120] The image forming system 100 according to this embodiment can control the amount of charge applied based on the results detected by the humidity detection unit 45.

[0121] (23) In the image forming system 100 described in item (1) above, the static elimination unit 32 may be configured to reduce the amount of charge applied to the front surface 111 (Figure 9) compared to the back surface 112 (Figure 9).

[0122] Since the image is formed on the back surface 112 (Figure 9) of the recording medium 110 later than on the front surface 111 (Figure 9), the effects of static electricity tend to remain on the back surface 112 more than on the front surface 111 (Figure 9). Taking this into consideration, the image forming system 100 according to this embodiment can reduce the effects of static electricity by increasing the amount of charge applied to the back surface 112 (Figure 9) of the recording medium 110 compared to the front surface 111 (Figure 9). This also allows the image forming system 100 to reduce the force of static electricity causing the recording media 110 stacked on the recording medium stacking device 15 and the discharge unit 17 to stick together.

[0123] (24) As shown in Figure 10, in the image forming system 100 of item (1) above, the static elimination unit 32 may be configured to apply more charge as the image density increases.

[0124] In this embodiment of the image forming system 100, by applying more charge as the image density increases, the electrostatic force causing the recording media 110 stacked on the recording media loading device 15 and the discharge unit 17 to stick together can be efficiently reduced.

[0125] (25) As shown in Figure 11, in the image forming system 100 of item (1) above, the static elimination unit 32 may be configured to apply a larger amount of charge as the recording medium transport speed increases.

[0126] In this embodiment of the image forming system 100, the amount of charge is increased as the recording medium transport speed increases, thereby efficiently reducing the electrostatic force that causes the recording media 110 stacked on the recording medium loading device 15 and the discharge unit 17 to stick together.

[0127] (26) As shown in Figure 1, the image forming system 100 in item (1) above may be configured to include another static elimination unit (static elimination contact member 22 of the static elimination device 21) upstream of the static elimination unit 32 of the static elimination device 31. The static elimination unit 32 is composed of needle-shaped electrodes, and the other static elimination unit is composed of the static elimination contact member 22.

[0128] In this embodiment of the image forming system 100, the recording medium 110 can be completely destaticized by another destaticization unit (the destaticization contact member 22 of the destaticization device 21), and each part of the recording medium 110 can be partially destaticized by the destaticization unit 32 (the needle-shaped electrode of the destaticization device 31). Therefore, the image forming system 100 can destaticize each part of the recording medium 110 accurately and effectively (uniformly).

[0129] As described above, the image forming system 100 according to this embodiment can reduce residual static electricity in each part of the recording medium.

[0130] It should be noted that the present invention is not limited to the embodiments described above, and various modifications and variations can be made without departing from the spirit of the invention.

[0131] For example, the embodiments described above are explained in detail to make the gist of the present invention easier to understand. Therefore, the present invention is not necessarily limited to having all the components described. Furthermore, the present invention can be modified by adding other components to one component, or by changing some components to other components. Furthermore, the present invention can be modified by deleting some components. [Explanation of Symbols]

[0132] 11 Control section 12 Paper feeder 13 Image forming apparatus 13a Image forming unit 13b Fixing section 13c Conveyor section 13d Control Unit 14. Improper recording medium loading device 14a First improper recording medium loading device 14b Second improper recording medium loading device 14c Third improper recording medium loading device 15 Recording medium loading device 15a First recording medium loading device 15b Second recording medium loading device 16 bogies 17 Discharge section 18 Conveyor path 21 Static eliminator 22. Static elimination contact member (other static elimination part) 31,31a,31b Static eliminator 32. Static elimination section (charge application section, needle-shaped electrode) 33 Control Unit 34 Power supply section 35 Post-processing 36 Conveying section 41 Image density detection unit 42 Surface electrometer 43 Recording medium position detection unit 44 Charge quantity detection unit 45 Humidity detection unit 46. ​​Transport speed detection unit 51 Guide section 51a Upper guide section 51b Lower guide section 52 Guide surface 53 Opening 99 Overall Control Unit 100 Image Forming Systems 110 Recording media 110a Previous recording medium 110b Next recording medium 111 Front side 112 Reverse side 121 Conveying direction 122 Intersecting direction 131 Image density 131a Dark area 131b Pale area

Claims

1. An image forming system for forming electrophotographic images, An image forming unit that forms an image on a recording medium, A transport path for transporting the recording medium, The system comprises a plurality of static elimination units arranged in a direction intersecting the transport direction of the recording medium, which de-charge the recording medium according to the image density of the recording medium that has been charged by image formation and / or transport, thereby de-charging the recording medium. Image forming system.

2. A fixing unit is located downstream of the image forming unit and is used to fix the image onto a recording medium. The static elimination unit is located downstream of the fixing unit on the transport path. The image forming system according to claim 1.

3. It is equipped with a recording medium loading device for loading the recording medium after printing, The static elimination unit is located upstream of the recording medium loading device. The image forming system according to claim 1.

4. The static elimination unit is positioned so as not to come into contact with the recording medium. The image forming system according to claim 1.

5. The static elimination unit is positioned so as not to protrude from the guide surface that guides the recording medium. The image forming system according to claim 1.

6. It includes a guide section for guiding the transport of the recording medium, An opening is provided in the guide portion for allowing the charge generated from the static elimination unit toward the recording medium to pass through. The image forming system according to claim 1.

7. The static elimination unit is a needle-shaped electrode. The image forming system according to claim 1.

8. It includes a control unit that controls the amount of charge applied based on the image density. The image forming system according to claim 1.

9. Each of the aforementioned static elimination units is equipped with an output-adjustable power supply unit that applies charge to each unit. The image forming system according to claim 1.

10. An image density detection unit that detects the image density on the recording medium, The system includes a control unit that controls the amount of charge applied based on the results detected by the image density detection unit. The image forming system according to claim 1.

11. The static elimination unit applies charge to adjacent recording media in the recording media stacking direction such that the opposing surfaces have the same polarity. The image forming system according to claim 1.

12. The static elimination unit applies charge to adjacent recording media in the recording media stacking direction such that the absolute values ​​of the charge amounts on the opposing surfaces are equal. The image forming system according to claim 11.

13. The static elimination unit switches the amount of charge applied for each recording medium. The image forming system according to claim 11.

14. The static elimination unit allows the amount of charge to be applied to be manually specified. The image forming system according to claim 11.

15. The static elimination unit is located on both sides of the transport path. The image forming system according to claim 1.

16. Image density detection units are provided on both sides of the transport path. The image forming system according to claim 15.

17. Surface potential meters are provided on both sides of the aforementioned transport path. The image forming system according to claim 15.

18. The static elimination unit is arranged in multiple rows in the transport direction of the recording medium. The image forming system according to claim 1.

19. The static elimination unit is composed of needle-shaped electrodes, The needle-shaped electrodes are arranged in multiple rows at positions with different phases in a direction intersecting the transport direction of the recording medium. The image forming system according to claim 18.

20. A recording medium position detection unit that detects the position of the recording medium, The system includes a control unit that controls the timing of applying charge based on the results detected by the recording medium position detection unit, The image forming system according to claim 1.

21. A charge amount detection unit that detects the amount of charge of the recording medium, The system includes a control unit that controls the amount of charge applied based on the results detected by the charge quantity detection unit. The image forming system according to claim 1.

22. A humidity detection unit that detects humidity, The system includes a control unit that controls the amount of charge applied based on the results detected by the humidity detection unit. The image forming system according to claim 1.

23. The static elimination unit reduces the amount of charge applied to the front surface compared to the back surface. The image forming system according to claim 1.

24. The static elimination unit applies more charge as the image density increases. The image forming system according to claim 1.

25. The static elimination unit applies a larger amount of charge as the recording medium transport speed increases. The image forming system according to claim 1.

26. Another static elimination unit is provided upstream of the aforementioned static elimination unit, The static elimination unit is composed of needle-shaped electrodes, The other static elimination unit is composed of a static elimination contact member. The image forming system according to claim 1.

Images