Image reading device and image forming apparatus

Abstract

This reduces the likelihood of the filler coming into contact with and damaging the original document. [Solution] A scanner unit 2 (document placement unit) on which a document D can be placed is provided. Furthermore, an automatic document transport unit M (document holding unit) is provided, which has a pressure plate 75 on its bottom surface that can press against the document D placed on the second contact glass 82 (placement surface) of the scanner unit 2 from above, and which can open and close the second contact glass 82 by rotating around a hinge Mx (rotation axis). In addition, a filler 76 is provided which is held in the automatic document transport unit M so as to be rotatable around a pivot shaft 76a, and a sensor 83 is installed in the scanner unit 2 which detects the filler 76 when the opening and closing angle of the pressure plate 75 with respect to the second contact glass 82 around the hinge Mx is less than or equal to a first predetermined value α. The filler 76 is configured to be retractable to a retracted position in which it does not protrude from the bottom surface (pressure plate 75) when the automatic document transport unit M is open.

Description

Technical Field

[0001] The present invention relates to an image reading device that reads an image of a document, and an image forming device such as a copying machine, a printer, a facsimile machine, or a multifunction machine or a printing machine including the same.

Background Art

[0002] Conventionally, in an image forming device such as a copying machine, a printer, or a printing machine, as an image reading device that reads an image of a document, there is known one provided with a document pressing portion that is opened and closed when a document is manually placed on a document placement portion (for example, see Patent Document 1).

[0003] Specifically, in an image reading device such as Patent Document 1, a pressure plate is provided on the bottom surface of a document pressing portion (opening and closing pressing means). After placing a document on the placement surface (contact glass) of the document placement portion in a state where the document pressing portion is open, the document pressing portion is closed and the document on the placement surface is pressed by the pressure plate, and image information of the document is read by a scanner that moves in the scanning direction below the placement surface. At this time, the opening and closing of the document pressing portion is determined by whether a filler provided in the document pressing portion is optically detected by a sensor (transmission type sensor) provided in the document placement portion.

[0004] On the other hand, Patent Document 1 discloses a technique in which, even when the document pressing portion is closed with a document placed on the sensor in the document placement portion, the filler that comes into contact with the document is configured to rotate around a support shaft and retract so that the filler is not damaged by the document intervening between the sensor and the filler.

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a conventional image reading device, there is a possibility that a problem may occur in which a filler comes into contact with a document and is damaged when a thick book or the like is placed on the document placement portion as a document. In contrast, the image reading device described in Patent Document 1 could not solve this problem because the filler would not retract to its retracted position unless it made contact with the document placed across the sensor from above.

[0006] This invention was made to solve the above-mentioned problems and aims to provide an image reading device and an image forming device that are less prone to the problem of the filler coming into contact with and damaging the original document. [Means for solving the problem]

[0007] The image reading device in this invention comprises: a document placement section on which a document can be placed; a document holder section having a pressure plate on its bottom surface that can press down on the document placed on the placement surface of the document placement section from above, and which can open and close the placement surface by rotating around a pivot axis; a filler held by the document holder section so as to be rotatable around a pivot axis; and a sensor installed in the document placement section that detects the filler when the opening and closing angle of the pressure plate with respect to the placement surface about the pivot axis is less than or equal to a first predetermined value, wherein the filler is configured to be retractable to a retracted position in which it does not protrude from the bottom surface when the document holder section is open. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an image reading device and an image forming device that are less prone to the problem of the filler coming into contact with and damaging the original document. [Brief explanation of the drawing]

[0009] [Figure 1] This is an overall configuration diagram showing an image forming apparatus according to Embodiment 1 of this invention. [Figure 2] This is a diagram showing the configuration of an image reading device. [Figure 3] This is a perspective view showing the operation of closing the document automatic transport unit (document holder) in an image reading device, which is in an open state. [Figure 4]This is an enlarged view showing the main parts of the image reading device with the automatic document transport section closed. [Figure 5] This is a perspective view showing the filler in the state detected by the sensor. [Figure 6] This diagram shows the operation of the filler when the open document automatic feed unit is closed. [Figure 7] This diagram shows part of the filler's operation when the automatic document feeder is opened. [Figure 8] This is a perspective view showing the weight connected to the filler. [Figure 9] (A) A diagram showing a book placed on the scanner in the image reading device of this embodiment, and (B) A diagram showing a book placed on the scanner in an image reading device as a comparative example. [Figure 10] This is a modified example, an enlarged view showing the main parts of an image reading device. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments for carrying out this invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and redundant explanations will be simplified or omitted as appropriate.

[0011] First, Figures 1 and 2 illustrate the overall configuration and operation of the image forming apparatus. In Figure 1, 1 represents a copier as an image forming apparatus, and 10 represents an image reading apparatus that optically reads image information from the original document D. Referring to Figure 2, the image reading apparatus 10 consists of a scanner section 2 as an original document placement section on which a contact glass 82 (placement surface) is installed, and an automatic original document transport section M as an original document holding section on which a pressure plate 75 is installed. Furthermore, 3 is an exposure unit (writing unit) that irradiates the photoreceptor drum 5 with exposure light L based on the image information of the original document D read by the image reading device 10, 4 is an imaging unit that forms a toner image (image) on the surface of the photoreceptor drum 5, and 7 is a transfer unit that transfers the toner image formed on the photoreceptor drum 5 to the sheet P (paper). These parts 3, 4, and 7 function as image forming units N that form an image on the sheet P based on the information (image information) of the original document D read by the image reading device 10. Furthermore, 12 and 13 indicate the feeding section where sheets P such as paper are stored, 17 is a register roller (timing roller) that transports the sheet P toward the transfer section 7, 20 is a fixing device that fixes the toner image (unfixed image) supported on the sheet P, 21 is a fixing roller installed in the fixing device 20, and 22 is a pressure roller installed in the fixing device 20. Also, 31 indicates an output tray on which sheets P discharged from the image forming apparatus body 1 are stacked.

[0012] Referring to Figure 1, the operation of the image forming apparatus main unit 1 during normal image forming will be described. First, the original document D is transported (fed) from the document glass 60 to the image reading device 10 and passes through the first CIS 80 (which is a contact image sensor). At this time, the first CIS 80 optically reads the image (image information) of the original document D as it passes through that position. The optical image information read by the first CIS 80 is then converted into an electrical signal and transmitted to the exposure unit 3 (writing unit). The exposure unit 3 then emits exposure light L, such as laser light, based on the electrical signal image information, toward the surface of the photosensitive drum 5 of the image formation unit 4.

[0013] Meanwhile, in the image-forming unit 4, the photoreceptor drum 5 rotates clockwise in the diagram, and after a predetermined image-forming process (charging process, exposure process, and development process), an image (toner image) corresponding to the image information is formed on the photoreceptor drum 5. Subsequently, the image formed on the surface of the photoreceptor drum 5 is transferred in the transfer unit 7 (image forming unit N) onto the sheet P, which has been transported by the register roller 17.

[0014] On one hand, the sheet P conveyed to the transfer unit 7 (image forming unit) operates as follows. First, one of the plurality of feeding units 12 and 13 in the image forming apparatus 1 is selected automatically or manually (for example, assume that the uppermost feeding unit 12 in the apparatus main body 1 is selected). Then, the uppermost sheet P stored in the feeding unit 12 is fed by a feeding mechanism 52 (constituted by a feed roller, a pickup roller, a backup roller, etc.) and conveyed toward the conveyance path. After that, the sheet P passes through the conveyance path where a plurality of conveyance rollers are arranged and reaches the position of the registration roller 17.

[0015] The sheet P that has reached the position of the registration roller 17 is conveyed toward the transfer unit 7 (image forming unit) while synchronizing the timing to align with the image formed on the photosensitive drum 5. After the transfer process, the sheet P passes through the position of the transfer unit 7 and then reaches the fixing device 20 via the conveyance path. The sheet P that has reached the fixing device 20 is fed between the fixing roller 21 and the pressure roller 22, and the toner image is fixed by the heat received from the fixing roller 21 and the pressure received from both members 21 and 22 (this is the fixing process). After the fixing process in which the toner image is fixed, the sheet P is sent out from between the fixing roller 21 and the pressure roller 22 (this is the fixing nip), then discharged from the image forming apparatus main body 1, and stacked on the discharge tray 31 as an output image. In this way, a series of image forming processes is completed.

[0016] Next, the image reading device 10 will be described in detail using FIG. 2 and the like. As shown in FIG. 2, the image reading device 10 is composed of an automatic document conveyance unit M as a document pressing unit, a scanner unit 2 as a document placement unit, and the like. The automatic document conveyance unit M is composed of a document table 60 (automatic conveyance document table), a document discharge unit 62 (paper discharge tray), a pickup roller 63, a separation roller 64, a feed roller 65, a plurality of conveyance rollers 66 to 72, a second CIS 90, a pressure plate 75, and the like. The scanner unit 2 consists of a first CIS 80 as an image reading unit, a first contact glass 81, a second contact glass 82 (document placement plate) as a placement surface (document placement surface), and the like.

[0017] Here, the document tray 60 has an open space above it, and is configured so that the user can place documents D (including a stack of documents consisting of multiple documents D) on it from above. Furthermore, the document tray 60 is configured to be partially adjustable so that the height of the uppermost document D among the multiple documents D stacked on it remains constant.

[0018] The document ejection unit 62 is located below the document tray 60 and is configured to eject and place the document D (including a stack of multiple documents D) after the image has been read by the first CIS 80 and the second CIS 90.

[0019] Furthermore, the transport path from the document tray 60 to the document discharge unit 62 is equipped with, in order from upstream, a pickup roller 63, an FRR type feeding mechanism (feed roller 65, separation roller 64), and multiple transport rollers 66 to 72. These components 63 to 72 function as transport means that transport the document D placed on the document tray 60 toward the first CIS 80 and the second CIS 90, and then transport the document D toward the document discharge unit 62.

[0020] The first CIS, which functions as an image reading unit, is a contact image sensor that reads image information of the original document D, which is transported by transport rollers 66-68 and passes the position of the first contact glass 81, via the first contact glass 81. Furthermore, the first contact glass 81 is made of a light-transmitting material such as glass and is installed in the transport path.

[0021] The following describes the operation of reading only the image formed on one side of the document D set on the document glass 60 (single-sided reading operation) in the image reading device 10 configured as described above. First, on the document table 60, the original document D (with an image formed on its top surface) is loaded with its leading edge (the leading edge in the transport direction) abutting against the reference wall. Then, when an instruction to read the image of the original document D (copy instruction) is given by operating the control panel (not shown), the pickup roller 63 transports the original documents D on the document table 60 sequentially from the top towards the FRR type feeding mechanism (feed roller 65, separation roller 64). At this time, multiple original documents D may be transported, but due to the separation of the FRR type, only the uppermost original document D is separated and sent to the downstream transport path. Subsequently, the document D, transported along the transport path, strikes the nip portion of the stop-rotating pull-out roller 66, where skew correction (oblique correction) is performed. After skew correction, the document D is transported downstream by the now-rotating pull-out roller 66 and transported to the position of the first CIS 80 (and first contact glass 81) by the first and second transport rollers 67 and 68. The image (image information) of the document D is then optically read by the first CIS 80. Subsequently, the scanned document D is ejected to the document ejection section 62 by the transport rollers 69-71 and the ejection roller pair 72. In this way, the document D set on the document tray 60 is transported in the direction of the dashed arrow in Figure 2, passing through a partially curved transport path. This series of document transport operations will be repeated for all documents D placed on the document tray 60.

[0022] Furthermore, when reading an image formed on the back side of the original document D in addition to the image formed on the front side, the original document D, after the image on the front side has been read by the first CIS 80 (and the first contact glass 81), is then transported to the position of the second CIS 90 (which is a contact image sensor). The image on the back side of the original document D is then optically read by the second CIS 90. Subsequently, the document D, from which the image on the reverse side has been read, is ejected to the document ejection unit 62 by the ejection roller pair 72. Furthermore, the first and second CIS80 and 90 extend in the width direction (the direction perpendicular to the paper surface in Figures 1 and 2) and are configured to include at least the entire width of the largest size original document D (so that the image of the largest size original document D can be read across its width).

[0023] In this embodiment, the image reading device 10 does not read images while automatically transporting the original document D (i.e., the original document transport unit M performs original document transport and image reading), but is configured to read images even when the original document D is not automatically transported and is manually placed and fixed (non-transported). More specifically, a second contact glass 82 is installed on the upper surface of the scanner unit 2, which serves as the document placement area (the surface facing the bottom surface of the automatic document transport unit M), as a placement surface (document placement plate) on which the document D can be placed in a nearly horizontal position. The second contact glass 82 as a placement surface is made of a light-transmitting material such as glass, and is configured so that the height of its upper surface is nearly equal to the height of the upper surface of the scanner unit 2. Furthermore, referring to Figures 3 and 6, the automatic document transport unit M is configured as an openable and closable document holder above the second contact glass 82 (document placement plate) which serves as the placement surface, and a pressure plate 75 (which has appropriate elasticity, similar to known types) is installed on its bottom surface (underside).

[0024] Then, as shown in Figure 3(C), when reading an image of the original document D placed on the second contact glass 82 (mounting surface) (when the original document D is fixed and image reading is performed), the original document D is sandwiched between the second contact glass 82 and the pressure plate 75. Specifically, as shown in Figure 3(A), the closed automatic document transport unit M (document holder) is opened, and the document D (with the front side (image reading surface) facing downwards) is placed on the upper surface of the exposed second contact glass 82. Then, as shown in Figures 3(B) and (C), the open automatic document transport unit M is closed so that the document D placed on the second contact glass 82 is sandwiched between the pressure plate 75 (the state shown in Figure 3(C)). Note that Figure 3(A') is an enlarged view of the area enclosed by the dashed line in Figure 3(A). Then, when an instruction to read the image of the original document D (copy instruction) is given by operating the control panel (not shown), the first CIS 80 moves in the scanning direction (left-right direction in Figure 2, which is perpendicular to the width direction) while in contact with the lower surface of the second contact glass 82 by the moving mechanism (not shown), and the image of the entire original document D is optically read. In this embodiment, the first CIS80 (image reading unit) used when reading an image with the document D fixed and not being transported is the same first CIS80 used when reading an image while the document D is being transported by the automatic document transport unit M, but moved and shared.

[0025] The characteristic configuration and operation of the image reading device 10 (image forming apparatus 1) in this embodiment will be described in detail below with reference to Figures 2 to 9, etc. As explained earlier using Figures 2 and 3, the image reading device 10 in this embodiment is provided with a scanner unit 2 that functions as a document placement unit on which a document D can be placed. The scanner unit 2 is provided with a second contact glass 82 on its upper surface that functions as a placement surface on which the document D is placed. Furthermore, the image reading device 10 has a pressure plate 75 installed on its bottom surface (the bottom surface in the closed state) that can press down on the document D placed on the second contact glass 82 (placement surface) of the scanner unit 2 (document placement unit) from above, and an automatic document transport unit M that functions as a document holder is provided. This automatic document transport unit M functions as a document holder that can open and close the second contact glass 82 (placement surface) by rotating around a hinge Mx that functions as a rotation axis. More specifically, the hinge Mx, which serves as the rotation axis (center of rotation), is located on the back side when viewed from the front side where an operator such as a user faces the image reading device 10 (image forming device 1), and the automatic document transport unit M (document holder) rotates around one side of its back side as the center of rotation. In this specification, "hinge Mx" is defined in a broad sense as a "rotation axis".

[0026] Referring to Figures 4 to 7, the image reading device 10 (image forming device 1) in this embodiment is provided with detection means (mainly a sensor 83 and a filler 76) for detecting the opening and closing of the automatic document transport unit M (document holder unit). The filler 76 (detected plate) is a thin, plate-shaped member held in the automatic document transport unit M (document holder) so as to be rotatable around the support shaft 76a. Therefore, the filler 76 moves around the hinge Mx in conjunction with the opening and closing operation (rotation) of the automatic document transport unit M. Sensor 83 is a transmissive photosensor that optically detects whether or not filler 76 is present between the light-emitting element and the light-receiving element (detection range 83a), and is installed in the scanner unit 2 (document placement unit). In particular, in this embodiment, sensor 83 is set to detect filler 76 when the opening and closing angle (angle) of the pressure plate 75 with respect to the second contact glass 82 (placement surface) around the hinge Mx (rotation axis) is less than or equal to a first predetermined value α (degrees). That is, even if the automatic document transport unit M (document press unit) is not completely closed (as shown in Figure 6(D)), but is in a half-open state with an opening and closing angle of less than or equal to the first predetermined value α (degrees), as shown in Figure 6(C), if a part of the filler 76 is within the detection range 83a of sensor 83, it is determined that the scanner unit 2 is in a state where it can read the document D.

[0027] Then, when the automatic document transport unit M is detected by the sensor 83 detecting the filler 76, the size of the document D placed on the second contact glass 82 is detected by the document size detection sensor (not shown) installed in the scanner unit 2, and the scanner unit 2 becomes ready to read the image information of the document D. As explained earlier, in this embodiment, even if the automatic document transport unit M (document holder) is not completely closed (as shown in Figure 6(D)), as long as the opening / closing angle is less than or equal to the first predetermined value α (degrees), the size of the document D placed on the second contact glass 82 is detected, even if there is a gap between the second contact glass 82 and the automatic document transport unit M, and the scanner unit 2 becomes capable of reading the document D. Therefore, even if a thick document D' such as a book or notebook is placed on the second contact glass 82, it is possible to read the document in the same way as when a normal, thin document D is placed on the second contact glass 82. In other words, as shown in Figure 9(A), if the opening / closing angle of the automatic document transport unit M (document holder) is less than or equal to the first predetermined value α (degrees), the document D' can be read even if a thick document D' is placed on the second contact glass 82 and the automatic document transport unit M is not completely closed. The first predetermined value α mentioned above is set to match the upper limit of the thickness of the document D' that can be read properly when the automatic document transport unit M is not completely closed.

[0028] Here, as shown in Figures 6(A) and 7(B), in this embodiment, the filler 76 is configured to be retracted (stored) to a retracted position where it does not protrude from the bottom surface (pressure plate 75) when the automatic document transport unit M (document press unit) is open. For details, please refer to Figure 6. In this embodiment, when the opening and closing angle of the automatic document transport unit M (document holder) is greater than the first predetermined value α (degrees) and less than or equal to the second predetermined value β (degrees) (>α), the filler 76 protrudes from the bottom surface (pressure plate 75) toward the scanner unit 2 (document placement unit). In contrast, when the opening and closing angle of the automatic document transport unit M (document holder) exceeds the second predetermined value β (degrees), the filler 76 does not protrude from the bottom surface (pressure plate 75). The second predetermined value β mentioned above is set to the minimum opening angle of the automatic document transport unit M required when the document D is placed on the second contact glass 82. Therefore, the second predetermined value β is set to an angle smaller than the maximum opening and closing angle of the automatic document transport unit M. Furthermore, in this embodiment, since the lower surface of the pressure plate 75 is formed to protrude slightly downward (towards the second contact glass 82) relative to the bottom surface of the automatic document transport unit M, the presence or absence of protrusion of the filler 76 from the bottom surface of the automatic document transport unit M, based on the second predetermined value β described above, is considered to be approximately the same as the presence or absence of protrusion from the pressure plate 75, and there is no difference in the effects of the present invention described later. On the other hand, if the amount of downward protrusion of the lower surface of the pressure plate 75 relative to the bottom surface is not negligible, it is preferable to prioritize the presence or absence of protrusion of the filler 76 from the bottom surface of the automatic document transport unit M, based on the second predetermined value β, while considering the possibility that the document D may come into contact with the filler 76 when setting the document D on the second contact glass 82.

[0029] As shown in Figure 6(A), when the automatic document transport unit M (document holder) is fully open (when the opening / closing angle is at its maximum value), the filler 76 is retracted to a position where it does not protrude from the bottom surface (pressure plate 75) of the automatic document transport unit M. In this embodiment, the maximum opening / closing angle of the automatic document transport unit M (the opening / closing angle when it is fully open) is set to 90 degrees or a slightly larger angle. Then, the automatic document transport unit M is closed from the open position in Figure 6(A) (the opening and closing angle is gradually reduced), and when the opening and closing angle reaches β (>α) as shown in Figure 6(B), the filler 76, which was in the retracted position, rotates counterclockwise around the support shaft 76a in Figure 6 and protrudes from the bottom surface (pressure plate 75). However, at this time, the filler 76 is still outside the detection range 83a of the sensor 83. Then, as the automatic document transport unit M is further closed (the opening and closing angle is gradually reduced), as shown in Figure 6(C), when the opening and closing angle reaches α (<β), the filler 76, which is protruding from the bottom surface (pressure plate 75), is positioned within the detection range 83a of the sensor 83. Then, as the automatic document transport unit M is further closed (the opening and closing angle is gradually reduced), as shown in Figure 6(D), when the opening and closing angle becomes approximately 0 degrees, the automatic document transport unit M is completely closed.

[0030] In contrast, when the automatic document transport unit M is opened from the closed position shown in Figure 6(D), the reverse operation of the operations shown in Figures 6(A) to (D) is performed. When the opening and closing angle of the automatic document transport unit M exceeds the second predetermined value β, the filler 76 rotates around the support shaft 76a in the direction of the white arrow shown in Figure 7(A), and finally settles into a retracted position where it does not protrude from the bottom surface (pressure plate 75), as shown in Figure 7(B).

[0031] Thus, in this embodiment, when the automatic document transport unit M is open, the filler 76 is configured to be retracted (stored) to a retracted position where it does not protrude from the bottom surface (pressure plate 75), making it less likely for the filler 76 to come into contact with the document D and be damaged. In more detail, as shown in Figure 9(B) as an example, in the image forming apparatus 100, which is configured so that the filler 76 does not retract when the automatic document transport unit M is open, there was a possibility that the filler 76 would be damaged when the document D' came into contact with the filler 76 protruding from the bottom surface (pressure plate 75) from the side or front. In contrast, in this embodiment, the image reading device 10 (image forming device 1) retracts the filler 76 so that it does not protrude from the bottom surface (pressure plate 75) when the automatic document transport unit M is open, as shown in Figure 9(A), making it less likely for the filler 76 to come into contact with a thick document D'. Therefore, the problem of the filler 76 being damaged is less likely to occur. In particular, in this embodiment, when the opening and closing angle of the automatic document transport unit M exceeds the second predetermined value β necessary to place the document D on the second contact glass 82, the filler 76 is retracted to a position where it does not protrude from the bottom surface (pressure plate 75), so the problem of the filler 76 coming into contact with the document D and being damaged is less likely to occur.

[0032] More specifically, as shown in Figure 5 and other figures, the image reading device 10 in this embodiment is provided with a weight 79 connected to the filler 76 via a string-like member 78, and a torsion spring 77 as a biasing member that biases the filler 76 in a rotational direction so that it protrudes from the pressure plate 75 (bottom surface). More specifically, as shown in Figure 5, the filler 76 is formed in a roughly key shape, and its pivot shaft 76a, formed at its base, is rotatably held by a holding part Ma formed on the automatic document transport unit M. Furthermore, to prevent the operator from accidentally touching the filler 76 when setting the document, the pivot shaft 76a of the filler 76 is positioned near the hinge Ma (rotation axis) of the automatic document transport unit M when viewed in the axial direction. Furthermore, the torsion spring 77 (biasing member) has its coil portion wound around the support shaft 76a, with one arm portion hooked onto the body portion of the filler 76 and the other arm portion hooked onto the holding portion Ma. Due to the spring force of this torsion spring 77, a force constantly acts on the filler 76 to cause it to rotate counterclockwise around the support shaft 76a as shown in Figure 6. Although not shown in the illustration, a stopper portion (a projection that interferes with the filler 76 when it rotates to a predetermined position) is provided on the document automatic transport unit M to limit the rotation of the filler 76 so that it does not rotate indefinitely due to the spring force of the torsion spring 77. Furthermore, the weight 79 is connected to the filler 76 via a string-like member 78 at a position (connecting part 76b) away from the support shaft 76a. By positioning the connecting part 76b at a position sufficiently far from the support shaft 76a in this way, the weight of the weight 79 that imparts rotational force to the filler 76 in a direction opposite to the biasing force of the torsion spring 77 can be reduced compared to when it is positioned near the support shaft 76a. Furthermore, the string-like member 78 is made of a flexible material that allows the weight of the sinker 79 to act directly on the filler 76, and has sufficient strength to prevent it from being cut or damaged by the weight of the sinker 79.

[0033] When the opening and closing angle of the automatic document transport unit M is less than or equal to the second predetermined value β, the weight 79 is held in the automatic document transport unit M (document holder) so that gravity does not act on the filler 76, and the filler 76 rotates counterclockwise around the support shaft 76a in Figure 6 so that it protrudes from the pressure plate 75 (bottom surface) due to the biasing force of the torsion spring 77 (biasing member). In the document automatic transport unit M, the state in which the weight 79 is held so that its gravity does not act on the filler 76 is as shown in Figures 6(B) to (D), etc., where the weight 79 rests on the inner wall of the document automatic transport unit M and no tension is generated in the string-like member 78. In contrast, when the opening and closing angle of the automatic document transport unit M exceeds the second predetermined value β, the gravity of the weight 79 acts on the filler 76 in the automatic document transport unit M (document holder) to counteract the biasing force by the torsion spring 77 (biasing member), causing the filler 76 to rotate to a retracted position where it does not protrude from the pressure plate 75 (bottom surface) (it rotates clockwise in Figure 6 around the pivot shaft 76a). In the document automatic transport unit M, the state in which the gravity of the weight 79 acts on the filler 76 is, as shown in Figure 6(A), etc., a state in which the weight 79 is not resting on the inner wall of the document automatic transport unit M (including a state in which it is in contact with the inner wall but is essentially floating), and tension is generated in the string-like member 78.

[0034] In this embodiment, the weight 79 is formed in a spherical shape as shown in Figure 8(A). However, if it is desired that the weight 79 not move freely when it is resting on the inner wall of the automatic document transport unit M, the weight 79 can be formed in a disc shape as shown in Figure 8(B), or in a rectangular shape as shown in Figure 8(C), or it can be made into a shape with corners.

[0035] <Variation> As shown in Figure 10, in the modified image reading device 10 (image forming device 1), the document automatic transport unit M (document holder unit) has a cushioning material 99 installed in the part that the weight 79 contacts. This cushioning material 99 is made of an elastic material such as foamed polyurethane, and by providing it, even if the weight 79 hits the inner wall of the automatic document transport unit M, it is less likely to generate abnormal noise and damage to the inner wall can be prevented. In another modified version, the document automatic transport unit M (document holder unit) has protrusions 99a and 99b formed thereon as restricting parts that limit the movement of the weight 79. Specifically, as shown in Figure 10, protrusions 99a and 99b are provided at both ends (or around the outer edge) of the cushioning material 99, restricting the weight 79, which is in contact with the cushioning material 99, from moving freely outside the range of the protrusions 99a and 99b. This makes it easier to fix the position of the weight 79, and the rotation of the filler 76 described above becomes smooth and stable. In the modified example, the protrusions 99a and 99b formed at the ends of the cushioning material 99 functioned as restrictors, but it is also possible to provide a restrictor in the automatic document transport unit M separately from the cushioning material 99.

[0036] As described above, the image reading device 10 in this embodiment is provided with a scanner unit 2 (document placement unit) on which a document D can be placed. Furthermore, an automatic document transport unit M (document holding unit) is provided, which has a pressure plate 75 on its bottom surface that can press against the document D placed on the second contact glass 82 (placement surface) of the scanner unit 2 from above, and which can open and close the second contact glass 82 by rotating around a pivot axis (hinge Mx). In addition, a filler 76 is provided which is held in the automatic document transport unit M so as to be rotatable around a support shaft 76a, and a sensor 83 is installed in the scanner unit 2 which detects the filler 76 when the opening and closing angle of the pressure plate 75 with respect to the second contact glass 82 around the pivot axis (hinge Mx) is less than or equal to a first predetermined value α. The filler 76 is configured to be retractable to a retracted position in which it does not protrude from the bottom surface (pressure plate 75) when the automatic document transport unit M is open. This reduces the likelihood of the filler 76 coming into contact with and damaging the original document D.

[0037] In this embodiment, the present invention was applied to an image reading device 10 installed in a monochrome image forming apparatus 1, but the present invention can naturally also be applied to an image reading device installed in a color image forming apparatus. Furthermore, although this embodiment applies the present invention to an image reading device 10 installed in an electrophotographic image forming apparatus 1, the application of the present invention is not limited to this, and the present invention can also be applied to image reading devices installed in other types of image forming apparatuses (for example, inkjet image forming apparatuses or stencil printing machines). Furthermore, in this embodiment, the automatic document transport unit M functions as a document holder. However, in an image reading device that does not have a function to automatically transport the document D, a document holder simply equipped with a pressure plate 75 will be used without a transport mechanism. In such a case, the scanner unit 2 (document placement unit) will not require the first contact glass 81 for automatic document transport, and will only be provided with one contact glass corresponding to the second contact glass 82 in this embodiment. Furthermore, even in such cases, the same effects as those of this embodiment can be obtained.

[0038] It is clear that the present invention is not limited to this embodiment, and that this embodiment can be modified as appropriate within the scope of the technical concept of the present invention, in addition to what is suggested here. Furthermore, the number, position, shape, etc. of the constituent members are not limited to this embodiment, and can be set to a number, position, shape, etc. that is suitable for carrying out the present invention.

[0039] In this application, "manuscript" is defined to include not only manuscripts made of paper, but also hard-material manuscripts such as driver's licenses, as well as all manuscripts made of sheet-like materials such as overhead projectors. [Explanation of Symbols]

[0040] 1. Image forming apparatus (image forming apparatus main unit), 2. Scanner section (document placement section), 10 Image reading device, 75 pressure plate, 76 fillers, 76a spindle, 77 Torsion spring (biasing member), 78 String-like member, 79 Weights (weights), 82 Second contact glass (mounting surface), 83 Sensor (detection means), 83a Detection range, 99 Elastic material (cushioning material), 99a, 99b Protruding part (restricting part), Manuscript D, Manuscript D' (book), M Automatic document feeding unit (document holding unit), Ma holding part, Mx hinge (rotating axis), N Image forming unit, α first predetermined value, β second predetermined value.

[0041] Furthermore, the embodiments of the present invention can also be, for example, combinations of appendices 1 to 10 as follows. (Note 1) A document placement section on which a document can be placed, The document holder has a pressure plate on its bottom surface that can press down on the document placed on the placement surface of the document placement section from above, and the document holder can open and close the placement surface by rotating around a pivot axis, A filler held in the document holder so as to be rotatable around a pivot shaft, A sensor installed in the document placement section detects the filler when the opening and closing angle of the pressure plate with respect to the placement surface described above, centered on the pivot axis, is less than or equal to a first predetermined value. Equipped with, The image reading device is characterized in that the filler is configured to be retractable to a retracted position in which it does not protrude from the bottom surface when the document holder is open. (Note 2) The image reading device according to Appendix 1, characterized in that the filler protrudes from the bottom surface toward the document placement area when the opening and closing angle is greater than or equal to a second predetermined value greater than the first predetermined value, and does not protrude from the bottom surface when the opening and closing angle exceeds the second predetermined value. (Note 3) The image reading device according to Appendix 2, characterized in that the second predetermined value is an angle smaller than the maximum value of the opening and closing angle. (Note 4) A weight connected to the filler via a string-like member, A biasing member that biases the filler in a rotational direction, protruding from the bottom surface, Equipped with, The aforementioned filler is, When the opening and closing angle is less than or equal to the second predetermined value, the weight is held in the document holder so that its gravity does not act on the filler, and rotates to protrude from the bottom surface due to the biasing force of the biasing member. The image reading device according to Appendix 2 or Appendix 3, characterized in that when the opening and closing angle exceeds the second predetermined value, the gravity of the weight acts on the filler in the document holder portion in opposition to the biasing force by the biasing member, causing it to rotate to the retracted position where it does not protrude from the bottom surface. (Note 5) The image reading device according to Appendix 4, characterized in that the weight is connected to the filler at a position away from the support shaft via the string-like member. (Note 6) The image reading device according to Appendix 4 or Appendix 5, characterized in that the weight is spherical, disc-shaped, or rectangular. (Note 7) The image reading device according to any one of the appendices 4 to 6, characterized in that the document holder portion has a cushioning material installed in the portion that comes into contact with the weight. (Note 8) The image reading device according to any one of the appendices 4 to 7, characterized in that the document holding portion has a limiting portion formed therein that restricts the movement of the weight. (Note 9) The image reading device according to any one of the appendices 1 to 8, characterized in that the support shaft is installed in the vicinity of the pivot shaft. (Note 10) An image reading device as described in any of Appendix 1 to Appendix 9, An image forming unit that forms an image on a sheet based on the information of the original document read by the aforementioned image reading device, An image forming apparatus characterized by comprising the following: [Prior art documents] [Patent Documents]

[0042] [Patent Document 1] Japanese Patent Publication No. 2002-341469

Claims

1. A document placement section on which a document can be placed, The document holder has a pressure plate on its bottom surface that can press down on the document placed on the placement surface of the document placement section from above, and the document holder can open and close the placement surface by rotating around a pivot axis, A filler held in the document holder so as to be rotatable around a pivot shaft, A sensor installed in the document placement section detects the filler when the opening and closing angle of the pressure plate with respect to the placement surface described above, centered on the pivot axis, is less than or equal to a first predetermined value. Equipped with, The image reading device is characterized in that the filler is configured to be retractable to a retracted position in which it does not protrude from the bottom surface when the document holder is open.

2. The image reading device according to claim 1, characterized in that the filler protrudes from the bottom surface toward the document placement area when the opening and closing angle is greater than or equal to a second predetermined value greater than the first predetermined value, and does not protrude from the bottom surface when the opening and closing angle exceeds the second predetermined value.

3. The image reading device according to claim 2, characterized in that the second predetermined value is an angle smaller than the maximum value of the opening and closing angle.

4. A weight connected to the filler via a string-like member, A biasing member that biases the filler in a rotational direction, protruding from the bottom surface, Equipped with, The aforementioned filler is, When the opening and closing angle is less than or equal to the second predetermined value, the weight is held in the document holder so that its gravity does not act on the filler, and rotates to protrude from the bottom surface due to the biasing force of the biasing member. The image reading device according to claim 2 or 3, characterized in that when the opening and closing angle exceeds the second predetermined value, the gravity of the weight acts on the filler in the document holder portion in opposition to the biasing force by the biasing member, causing it to rotate to the retracted position where it does not protrude from the bottom surface.

5. The image reading device according to claim 4, characterized in that the weight is connected to the filler at a position away from the support shaft via the string-like member.

6. The image reading device according to claim 4, characterized in that the weight is spherical, disc-shaped, or rectangular.

7. The image reading device according to claim 4, characterized in that the document holder portion has a cushioning material installed in the portion that comes into contact with the weight.

8. The image reading device according to claim 4, characterized in that the document holder portion has a limiting portion formed therein to restrict the movement of the weight.

9. The image reading device according to claim 1 or 2, characterized in that the support shaft is installed in the vicinity of the pivot shaft.

10. An image reading device according to claim 1 or claim 2, An image forming unit that forms an image on a sheet based on the information of the original document read by the aforementioned image reading device, An image forming apparatus characterized by comprising the following:

Images