Image reading apparatus and image forming system

Abstract

To provide an image reader capable of stably guiding paper to the image reading surface of a CIS and improving attaching / detaching workability.SOLUTION: An image reading apparatus for reading an image on a sheet conveyed along a conveyance path 69 includes a reading sensor 91 configured to optically read the image, a lifting device 83 configured to move the reading sensor 91 up and down between a reading height at which the reading sensor 91 is close to the conveyance path 69 and is capable of reading the image and a non-reading height at which the reading sensor 91 is separated upward from the conveyance path 69 with respect to the reading position, and a conveyance guide 85 disposed above the conveyance path 69 and configured to guide the sheet to an image reading position of the reading sensor 91. The conveyance guide 85 is pushed down by the reading sensor 91 lowered to the reading height, and is displaced from the retracted posture at a predetermined distance above the conveyance path 69 to a guiding posture closer to the conveyance path 69 than the retracted posture.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an image reading device that reads an image for inspection and an image forming system that includes the image reading device. [Background technology]

[0002] In an image forming system including an inkjet image forming apparatus, the quality of the image is affected by the condition of the recording head and ink. For example, if the nozzle surface of the recording head dries, the ink may thicken, causing ejection problems, or the ink may land in a position different from the desired position, causing white streaks in the image.

[0003] To prevent such image defects and maintain image quality, image forming systems are equipped with image reading devices that read and inspect images on paper, such as test charts. Based on the images read by the image reading device, defective nozzles in the recording head are identified and the image is corrected. This type of image inspection is performed, for example, approximately once every several thousand sheets.

[0004] As described in Patent Document 1, the image reading device is equipped with a reading sensor such as a CIS (Contact Image Sensor) that reads an image. The CIS is positioned so that its image reading surface faces the paper being transported along the transport path. The image reading surface is usually covered with a transparent glass plate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-111582 Summary of the Invention [Problem to be solved by the invention]

[0006] When using a CIS in this way, the distance between the image reading surface (glass plate) of the CIS and the transport surface along which the paper is transported is quite small, taking into consideration the depth of field, etc. The paper is transported in close contact with the transport surface of the transport path, but if the leading edge of the paper curls or lifts up from the transport surface, it may get caught on the CIS and cause paper transport problems.

[0007] Therefore, a transport guide is sometimes provided to guide the leading edge of the paper to the image reading surface of the CIS. As mentioned above, since the image reading surface of the CIS is located quite close to the transport surface, the transport guide must also be located close to the transport surface. This can lead to the transport guide coming into contact with the transport surface when installing or removing the image reading device, potentially damaging the surface or deforming the transport guide. For this reason, the image reading device must be installed or removed without the transport guide coming into contact with the transport surface, which reduces the ease of installing and removing the image reading device.

[0008] In consideration of the above circumstances, the present invention aims to provide an image reading device and an image forming system equipped with the image reading device that can stably guide paper to the image reading surface of a CIS and has improved attachment and detachment workability. [Means for solving the problem]

[0009] In order to achieve the above object, the image reading device of the present invention is an image reading device that reads an image of paper transported along a transport path, and is equipped with a reading sensor that optically reads the image, a lifting device that raises and lowers the reading sensor to a reading height close to the transport path where the image can be read, and a non-reading height that is further away from the transport path than the reading position, and a transport guide that is positioned above the transport path and guides the paper to an image reading position by the reading sensor, and is characterized in that the transport guide is pushed down by the reading sensor that has lowered to the reading height, and is displaced from a retracted position that is a predetermined distance above the transport path to a guiding position that is closer to the transport path than the retracted position.

[0010] In the present invention, the transport guide may be pressed down by the reading sensor that has descended to the reading height, bent downward at a predetermined position, and displaced into the guiding position, and a slit may be formed at the predetermined position of the transport guide.

[0011] The present invention may be characterized in that it further includes a housing that houses the reading sensor, the lifting device, and the transport guide, and has an opening through which the reading sensor passes when the reading sensor is raised or lowered, and the transport guide is supported on the edge of the opening.

[0012] In the present invention, the transport guide may protrude downward from the bottom surface of the housing in the retracted position, and the amount of protrusion of the transport guide from the bottom surface of the housing may be smaller than the amount of protrusion of other components.

[0013] The image forming system of the present invention includes an image forming device that forms an image on a sheet of paper, and an image reading device that reads the image formed by the image forming device. [Effects of the Invention]

[0014] According to the present invention, when an image is read, the transport guide is displaced from a retracted position to a guide position by the CIS unit, so that the transport of paper is not hindered except when the image is being read, and when the image is being read, the paper can be properly guided to the reading surface. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a perspective view schematically illustrating an image forming system according to an embodiment of the present invention. [Figure 2] 1 is a front view schematically showing the internal structure of a paper feed device, an image forming device, and a drying device of an image forming system according to an embodiment of the present invention. [Figure 3] 1 is a front view schematically illustrating the internal configuration of an image reading device according to an embodiment of the present invention (in a state where a CIS unit is raised to a non-reading height). [Figure 4]1 is a front view schematically showing the internal configuration of an image reading device according to an embodiment of the present invention (in a state where a CIS unit is lowered to a reading height). [Figure 5] FIG. 2 is a perspective view showing a transport guide of the image reading device according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] An image forming system and an image reading apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

[0017] First, the image forming system will be described with reference to Fig. 1. Fig. 1 is a perspective view showing the image forming system. L, R, Fr, and Rr, which are appropriately added in each figure, respectively indicate the left side, right side, front side, and rear side of the image forming system.

[0018] The image forming system 1 includes a paper feeder 3, an image forming device 5, a drying device 7, and a post-processing device 9. The paper feeder 3 stores paper sheets and feeds the paper sheets to the image forming device 5. The image forming device 5 is located to the left of the paper feeder 3 and forms an image on the paper sheets fed from the paper feeder 3 by inkjet printing, for example, based on image data input from an external computer. The drying device 7 is located to the left of the image forming device 5 and dries the paper sheets on which the image has been formed while transporting them. The post-processing device 9 is located to the left of the drying device 7 and performs post-processing on the paper sheets dried by the drying device 7.

[0019] Next, the paper feeder 3, the image forming device 5, and the drying device 7 will be described with reference to Fig. 2. Fig. 2 is a front view schematically showing the internal configuration of the image forming system 1.

[0020] First, the paper feed device 3 will be described. The paper feed device 3 includes two paper feed cassettes 11 that store paper, and a paper feed unit 13 that feeds paper from each paper feed cassette 11. A paper discharge port 15 and a paper receiving port 17 are formed on the left side of the paper feed device 3. The discharge port 15 is located at the top of the left side, and the receiving port 17 is located below the discharge port 15. A transport path 19 is formed between the two paper feed units 13 and the discharge port 15, along which paper is transported from the two paper feed cassettes 11 toward the image forming device 5. In addition, a duplex transport path 21 is formed between the receiving port 17 and the discharge port 15, along which paper is transported during duplex printing.

[0021] Next, the image forming device 5 will be described. The image forming device 5 has four head units 31 and four ink containers 33. The four head units 31 correspond to four colors of ink: black, cyan, magenta, and yellow, and are arranged along the paper transport direction (left-right direction). Each head unit 31 has multiple (three in one example) recording heads (not shown). Each recording head has a number of ink ejection nozzles. Each ink ejection nozzle ejects ink downward. The four ink containers 33 contain black, cyan, magenta, and yellow ink, respectively, and are connected to the corresponding head units 31.

[0022] Further, a right receiving opening 35 and a right discharging opening 37 for paper are formed on the right side surface of the image forming device 5. The right receiving opening 35 is disposed so as to face the discharging opening 15 of the paper feeding device 3. The right discharging opening 37 is disposed so as to face the receiving opening 17 of the paper feeding device 3. Further, a left discharging opening 39 and a left receiving opening 41 for paper are formed on the left side surface of the image forming device 5. The left discharging opening 39 is disposed at the top of the left side surface, and the left receiving opening 41 is disposed at the bottom of the left side surface.

[0023] A main transport path 43 is formed below the four head units 31 between the right receiving port 35 and the left discharge port 39. During image formation by the four head units 31, paper is transported along the main transport path 43 in a transport direction from the right receiving port 35 to the left discharge port 39. The main transport path 43 is composed of an endless transport belt 45 with numerous fine through-holes formed therethrough. The transport belt 45 is wound around a drive roller, a driven roller, and multiple tension rollers spaced apart from each other on the left and right. Rotation of the drive roller causes the transport belt 45 to travel counterclockwise in FIG. 2. The upper surface of the transport belt traveling along the upper traveling track constitutes the transport surface of the main transport path 43. Multiple suction devices 47 are disposed in the hollow portion of the transport belt 45. The suction devices 47 generate negative pressure in the through-holes of the transport belt 45 traveling along the upper traveling track, attracting the transported paper to the transport belt 45.

[0024] Furthermore, a duplex conveying path 49 is formed below the main conveying path 43 between the left receiving opening 41 and the right discharge opening 37. During duplex printing or image inspection, paper is conveyed along the conveying direction from the left receiving opening 41 to the right discharge opening 37. The duplex conveying path 49 is composed of upper and lower guide plates 51 and 53 that face each other at a predetermined interval in the vertical direction, and a pair of conveying rollers 55 that are arranged at a predetermined interval in the conveying direction. The lower guide plate 53 has a number of through-holes that penetrate it in the thickness direction. In addition, a suction device 57 is disposed below the lower guide plate 53. The suction device 57 generates negative pressure in the through-holes of the lower guide plate 53, attracting the conveyed paper to the lower guide plate 53.

[0025] An image reader 59 for reading an image of a test chart during image inspection is provided inside the left receiving opening 41 above the double-sided conveying path 49. The image reader 59 will be described later.

[0026] Next, the drying device 7 will be described. The drying device 7 includes a dryer 61. The dryer 61 includes multiple fans and a heater, heats the air taken in by the fans with the heaters, and blows the heated air downward.

[0027] A right receiving opening 63 and a right discharging opening 65 for paper are formed on the right side surface of the drying device 7. The right receiving opening 63 is disposed so as to face the left discharging opening 39 of the image forming device 5. The right discharging opening 65 is disposed so as to face the left receiving opening 41 of the image forming device 5. Furthermore, a left discharging opening 67 for paper is formed on the upper part of the left side surface of the drying device 7.

[0028] Between the right receiving port 63 and the left discharge port 67, a main transport path 69 is formed below the dryer 61, along which paper is transported in the transport direction from the right receiving port 63 to the left discharge port 67. The main transport path 69 branches into a reversing path 71 downstream of the dryer 61 in the transport direction. The reversing path 71 is connected to the right discharge port 65 via two reversing sections.

[0029] Next, a brief description will be given of the image forming operation of the image forming system 1. The paper discharged from the discharge port 15 of the paper feeder 3 is received by the image forming device 5 through the right receiving port 35 of the image forming device 5 and transported along the main transport path 43. The paper is transported while being attracted by the transport belt 45. At this time, four colors of ink are ejected from the four head units 31 according to the image data, and an image is formed on the paper. The paper with the image formed is discharged from the left discharge port 39, received by the drying device 7 through the right receiving port 63 of the drying device 7, and transported along the main transport path 69. At this time, the image formed on the paper is dried by the dryer 61.

[0030] In the case of single-sided printing, the paper is discharged from the left discharge port 67 to the post-processing device 9. In the post-processing device 9, the paper is subjected to a predetermined post-processing. In the case of double-sided printing, the paper passes through the main transport path 69 and the inversion path 71, and is transported alternately to two inversion units. After being inverted in the inversion units, the paper is received by the image forming device 5 from the right discharge port 65 through the left receiving port 41 of the image forming device 5 with the print side facing up. The paper is transported along the double-sided transport path 49 of the image forming device 5, and is received by the paper feeding device 3 from the right discharge port 37 through the receiving port 17 of the paper feeding device 3. The paper is transported along the transport path 19 from the receiving port 17 toward the discharge port 15, and is received by the image forming device 5 from the discharge port 15 through the right receiving port 35 of the image forming device 5. An image is then formed on the reverse side of the paper, as described above.

[0031] If the nozzle surfaces of the recording heads of each head unit 31 of the image forming device 5 dry out during the image forming operation, the ink may become viscous, causing ejection problems or the ink to land in a position different from the desired position. Therefore, as described above, image inspection is performed using the image reading device 59 approximately once every several thousand sheets.

[0032] Next, the image reading device 59 will be described with reference to Figures 3 and 4. Figures 3 and 4 are cross-sectional views showing the image reading device 59 in a schematic manner.

[0033] 3 and 4, the image reading device 59 includes a CIS unit 81, an elevator device 83 that raises and lowers the CIS unit 81 relative to the duplex conveying path 49, a conveying guide 85, and a housing 87 that supports these. The image reading device 59 is removably attached to the image forming device 5. As an example, the image reading device 59 is attached to and detached from the image forming device 5 in a direction (width direction, front-rear direction) that intersects with the conveying direction.

[0034] First, the housing 87 will be described. The housing 87 is a hollow member having a substantially rectangular parallelepiped shape. A rectangular opening 87a is formed in the bottom plate of the housing 87. When the image reading device 59 is attached to the image forming apparatus 5, the housing 87 is disposed above the duplex conveying path 49. At this time, a predetermined gap (for example, 2 mm or more) is provided between the lower surface of the bottom plate of the housing 87 and the conveying surface of the duplex conveying path 49 (the upper surface of the lower guide plate 53) so as not to interfere with the paper conveyed along the duplex conveying path 49.

[0035] Next, the CIS unit 81 will be described. The CIS unit 81 includes two CISs (Contact Image Sensors) 91 that can accommodate A4 size documents and a housing 93 that houses the two CISs 91. The two CISs 91 are arranged with their reading surfaces facing downward and their longitudinal axes aligned with the width direction (front-to-back direction), offset from each other in the width direction. This arrangement allows the readable width of the reading surfaces to be 350±0.5 mm, making it possible to read paper (such as test charts) with a maximum width (330.2 mm, 13 inches). The CISs 91 are an example of a reading sensor in the present invention. The detection results of the CISs 91 are output to an image inspection device (not shown).

[0036] The lower surface of the housing 93 (the surface facing the double-sided conveying path 49) is made of a transparent glass plate 95. In other words, the reading surface of the CIS 91 is covered with the glass plate 95.

[0037] Next, the lifting device 83 will be described. The lifting device 83 is a rack and pinion mechanism consisting of a rack 101 provided in the housing 93 of the CIS unit 81 along the vertical direction, and a pinion 103 supported by the casing 87 and meshing with the rack 101. The pinion 103 is connected to a motor (not shown) and is driven to rotate by the motor. By rotating the pinion 103, the CIS unit 81 moves up and down together with the rack 101 relative to the casing 87.

[0038] The elevator device 83 raises and lowers the CIS unit 81 to a reading height and a non-reading height. The reading height is a height at which the two CISs 91 can properly read the paper conveyed through the duplex conveying path 49. The CIS unit 81 passes through an opening 87a in the bottom plate of the housing 87 and descends to the reading height. At this time, the distance between the reading surface of the CIS unit 81 (the lower surface of the glass plate 95) and the duplex conveying path 49 (the upper surface of the lower guide plate 53) is, for example, 1 to 2 mm. The non-reading height is a predetermined height within the housing 87 that is higher than the reading height. A sensor (not shown) that detects the height of the CIS unit 81 is also provided within the housing 87. The pinion 103 rotates based on the detection result of the sensor to raise and lower the rack 101, i.e., the CIS unit 81, to an appropriate height including the reading height and the non-reading height.

[0039] Next, the transport guide 85 will be described with reference to Fig. 5. Fig. 5 is a perspective view showing the transport guide 85. The transport guide 85 guides paper to the reading position of the CIS unit 81 that has been lowered to the reading height. The transport guide 85 is a plate spring-like member that has a width equal to the width of the opening 87a formed in the bottom plate of the housing 87 and a predetermined length along the transport direction.

[0040] The conveying guide 85 is divided into a fixed portion 115, a central portion 117, and a tip portion 119, in that order from the upstream side in the conveying direction, by a first fold 111 and a second fold 113 along the width direction. The length along the conveying direction is longest at the central portion 117 and shortest at the tip portion 119. The central portion 117 is bent slightly downward relative to the fixed portion 115 via the first fold 111. The tip portion 119 is bent slightly upward relative to the central portion 117 via the second fold 113. Slits 121 are formed in the first fold 111 at predetermined intervals along the width direction.

[0041] 5, fixed portion 115 of conveying guide 85 is fixed with screws B to the upper surface of the bottom plate of housing 87, upstream of opening 87a in the conveying direction. Central portion 117 and tip end 119 of conveying guide 85 protrude into opening 87a (retracted position). As described above, central portion 117 and tip end 119 are bent, so second fold 113 between them protrudes furthest downward from opening 87a. The amount by which second fold 113 protrudes downward is smaller than the maximum amount by which other parts of image reading device 59 (screws, frame, etc.) protrude.

[0042] Further, the tip 119 of the transport guide 85 protruding into the opening 87a and the CIS unit 81 overlap in the vertical direction.

[0043] As mentioned above, the housing 87 accommodates a sensor that detects the height of the CIS unit 81, a correction plate 131 for correcting shading in the CIS 91, a cleaning member 133 that cleans the glass plate 95, a moving device that moves these components, etc. A description of these components will be omitted.

[0044] The image reading operation of the image reading device 59 in the image forming system 1 having the above configuration will now be described. While an image reading operation such as during image formation is not being performed, the lifting device 83 raises the CIS unit 81 to a non-reading height, as shown in Fig. 3. In addition, since the amount by which the conveying guide 85 protrudes downward from the housing 87 is small, the paper conveyed along the duplex conveying path 49 does not interfere with the conveying guide 85.

[0045] When reading an image, the elevator device 83 lowers the CIS unit 81 from the non-reading height to the reading height. The CIS unit 81 descends through the opening 87a of the housing 87. At this time, the lower surface of the CIS unit 81 (the lower surface of the glass plate 95) comes into contact with the tip 119 of the transport guide 85. As the CIS unit 81 descends, the tip 119 of the transport guide 85 is pressed downward. As a result, the center portion 117 of the transport guide 85 bends (elastically deforms) downward relative to the fixed portion 115 along the first fold 111. A slit 121 is formed in the first fold 111, making it easier for the center portion 117 to bend relative to the fixed portion 115.

[0046] As shown in FIG. 4, when the CIS unit 81 descends to the reading height, the center portion 117 tilts downward from the edge of the opening 87a toward the glass plate 95 of the CIS unit 81 (guiding position). Furthermore, the leading edge 119 comes into close contact with the glass plate 95 and becomes approximately parallel to the glass plate 95. The image on the paper transported along the duplex transport path 49 is read by the two CISs 91 as it passes through the transport position. The read results are sent to an image inspection device and inspected. The paper on which the image is formed during image reading is discharged to an escape tray (not shown) to prevent it from being mixed with other printed materials.

[0047] As described above, the paper is transported while being attracted to the lower guide plate 53 by the suction device 57, but depending on the transport and printing conditions, the leading edge of the paper may curl upward or lift off the transport surface. Even in such cases, the leading edge of the paper is guided to the reading surface of the CIS unit 81 by the center portion 117 of the transport guide 85, allowing the image to be read accurately.

[0048] When the image reading operation is completed, the elevator device 83 raises the CIS unit 81 to a non-reading height. When the CIS unit 81 rises and moves away from the transport guide 85, the transport guide 85 elastically returns to its original position.

[0049] As described above, according to the present invention, when an image is read, the transport guide 85 is displaced from the retracted position to the guiding position by the CIS unit 81, so that the transport of the paper is not impeded except when the image is being read, and the paper can be guided to the reading surface when the image is being read. In more detail, even if the leading edge of the paper curls upward or lifts off the transport surface, the leading edge of the paper can be guided to the reading surface of the CIS unit 81 by the transport guide 85, so the image can be read accurately.

[0050] Furthermore, when not reading an image, the transport guide 85 is retracted above the transport surface by a predetermined distance, so it does not interfere with the paper being transported along the duplex transport path 49. Furthermore, because the amount that the transport guide 85 protrudes downward from the housing 87 is small, the transport guide 85 is unlikely to interfere with the transport surface when the image reading device 59 is attached or detached. This prevents deformation of the transport guide 85 and damage to the transport surface, improving the workability of attaching and detaching the image reading device 59. Furthermore, when the image reading device 59 is placed alone on a work surface or the like, the transport guide 85 does not come into contact with the work surface, so damage and deformation of the transport guide 85 can be prevented.

[0051] Furthermore, when the CIS unit 81 is lowered to the reading height, the tip 119 of the conveying guide 85 adheres closely to the glass plate 95 of the CIS unit 81 and does not approach the conveying surface. Therefore, even during image reading, the paper is conveyed stably without interfering with the conveying guide 85.

[0052] Furthermore, since a slit 121 is formed in the first fold 111 of the conveying guide 85, the central portion 117 of the conveying guide 85 is easily bent relative to the fixed portion 115 when the CIS unit 81 is lowered. This allows the CIS unit 81 to be raised and lowered without resistance.

[0053] During image reading, the conveying guide 85 may be pressed down by a portion other than the glass plate 95 of the CIS unit 81. Furthermore, the first fold 111 of the conveying guide 85 may not have a slit formed therein, and the plate thickness may be thinner than other portions.

[0054] Although the present invention has been described with reference to specific embodiments, the present invention is not limited to the above embodiments, and various changes, substitutions, and modifications may be made without departing from the scope and spirit of the present invention, and the claims include all embodiments that may fall within the scope of the technical concept. [Explanation of symbols]

[0055] 1. Image forming system 5. Image forming device 59 Image reader 83 Lifting device 85 Transport guide 87 Case 87a aperture 91 CIS (reading sensor) 121 Slit

Claims

1. An image reading device that reads an image on a sheet of paper transported along a transport path, a reading sensor that optically reads the image; an elevating device that elevates the reading sensor between a reading height where the reading sensor is close to the conveying path and can read the image, and a non-reading height where the reading sensor is spaced above the conveying path beyond the reading position; a conveyance guide disposed above the conveyance path and configured to guide the paper to an image reading position by the reading sensor; The image reading device is characterized in that the transport guide is pushed down by the reading sensor that has lowered to the reading height, and is displaced from a retracted position that is a predetermined distance above the transport path to a guiding position that is closer to the transport path than the retracted position.

2. the conveying guide is pushed down by the reading sensor that has descended to the reading height, and is bent downward at a predetermined position to be displaced into the guiding position; 2. The image reading device according to claim 1, wherein a slit is formed in the transport guide at the predetermined position.

3. a housing that houses the reading sensor, the lifting device, and the transport guide, and has an opening through which the reading sensor passes when the reading sensor is lifted and lowered; 2. The image reading device according to claim 1, wherein the transport guide is supported on an edge of the opening.

4. the transport guide protrudes downward from a bottom surface of the housing in the retracted position, 4. The image reading device according to claim 3, wherein the amount of protrusion of the transport guide from the bottom surface of the housing is smaller than the amount of protrusion of other components.

5. an image forming device that forms an image on a sheet; an image reading device that reads an image formed by the image forming device;

Images