JP2024008606A - Document reading device and image forming apparatus - Google Patents

Abstract

To reduce the cost for a hinge mechanism.SOLUTION: A hinge mechanism (3) openably and closably supporting a document conveying unit with respect to an image reading unit has: a first member (31) that is fixed to the image reading unit; a first shaft (35); a second member (32) that rotates with respect to the first member; a second shaft (36); a third member (33) that rotates with respect to the second member; a third shaft (37); a fourth member (34) that rotates with respect to the second member so that the document conveying unit is fixed and a first contact part and a second contact part are in contact with the image reading unit; and a first urging part (F1) that has a first spring (53) providing torque in a direction to open the document conveying unit. The first member (31) has a pressure receiving member (31A) that receives the pressure of an urging force of the first spring (53) toward one side, and the third shaft (37) receives the pressure of an urging force of the first spring (53) toward the other side.SELECTED DRAWING: Figure 5

Description

The present invention relates to a document reading device and an image forming apparatus that include a hinge mechanism that opens and closes a document conveying unit to a document reading unit.

2. Description of the Related Art Conventionally, some image forming apparatuses, such as copy machines, fax machines, and multifunction peripherals, are equipped with a document reading device at the top for reading documents. In addition, some of the document reading devices are equipped with an image reading unit that reads the image of the document, and an document conveyance unit (hereinafter referred to as "ADF") that automatically conveys the document toward the document reading unit. be. In general, such document reading devices have two methods: fixed reading, in which the original is fixed on the fixed reading glass of the original reading unit, and the image is read, and so-called flowing reading, in which the original conveyed from the ADF is passed through the reading glass to read the image. It is configured so that it can be read and executed. Therefore, the ADF is supported by a hinge mechanism relative to the document reading unit, and is configured to be openable and closable relative to the document reading unit.

When the ADF is closed to the document reading unit, the pressure plate that presses the document against the fixed reading glass, or the abutting portion that abuts against both ends of the scanning glass in the width direction to form a conveyance path for the document, Preferably, it is pressed parallel to the surface of the glass. Further, when performing fixed reading, for example, when setting a thick original such as a book, it is desirable that the closed ADF be kept at a certain distance from the fixed reading glass. Therefore, a hinge mechanism has been proposed that includes three pivot points and four members that rotate relative to each other by the three pivot points (see Patent Document 1). In this patent document 1, the fixed end member (33) rotates about the fulcrum (f1) with respect to the fixed end member (32) fixed to the document reading unit, so that the entire ADF can read the document. The unit is configured to be openable and closable. In addition, by rotating the rotating end member (34) about the fulcrum (f2) with respect to the fixed end member (33), the distance between the ADF and the fixed reading glass is secured for thick originals. It is configured in such a way that it is possible. By rotating the upper stay (43) about the fulcrum (f3) with respect to the rotating end member (34), the degree of balance between them can be adjusted when the ADF is closed relative to the document reading unit. It is configured so that

In addition, since the ADF has a certain amount of weight, it has been proposed to improve operability by applying torque in the opening/closing direction using springs (54, 55) when opening/closing the ADF to the document reading unit. (See Patent Document 2). In this patent document 2, the biasing force of one of the springs that imparts torque is applied to the mounting member (2) via the pin (17 (FIG. 5)) or the shaft (103 (FIGS. 15 and 16)). is configured to be The other biasing force of this spring is received by the lift member (4) that opens and closes with respect to the mounting member (2) via the shaft (18 (Fig. 5), 106 (Fig. 15, Fig. 16)). It is configured to

Patent No. 3917097 Patent No. 5640303

As in Patent Document 1 mentioned above, the hinge mechanism is composed of three pivot points and four rotating members, and as in Patent Document 2, the hinge mechanism is configured to receive a spring and its biasing force. It is conceivable to provide two pressure receiving members. This makes it possible to adjust the balance when the ADF is closed while supporting thick originals during fixed reading, and also improves operability by applying torque in the opening/closing direction when opening/closing the ADF. It becomes possible. However, if the hinge mechanism is configured in this way, there is a problem that the number of parts increases, which hinders cost reduction.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a document reading device and an image forming device that can reduce the cost of a hinge mechanism.

One aspect of the present invention provides an image reading unit including a light-transmitting member that transmits light, a reading section that reads an image of a document through the light-transmitting member, and an image reading unit that transmits light through the light-transmitting member. a document transport unit that transports a document, and a hinge mechanism that supports the document transport unit so as to be openable and closable relative to the image reading unit; a second abutting portion that is disposed at a position closer to the hinge mechanism than the first abutting portion in a width direction perpendicular to the document conveyance direction and abuts the image reading unit; The hinge mechanism has a first member fixed to the image reading unit, a first shaft supported by the first member, and a shaft extending relative to the first member around the first shaft. a second member that rotates; a second shaft that is disposed in parallel at a different position from the first axis and supported by the second member; and a second shaft that rotates relative to the second member about the second axis; a third member disposed in parallel at a different position from the second shaft and supported by the third member; the document transport unit is fixed; a fourth member that rotates with respect to the third member about the third axis so that the abutting portion abuts the image reading unit; and a rotation angle of the document conveying unit with respect to the image reading unit. a first biasing portion having a first spring that applies a torque in a direction to open the document conveyance unit in response to the document transport unit, and the first member receives a biasing force of the first spring toward one side. The document reading device is characterized in that it has a pressure receiving member, and the third shaft receives the urging force of the first spring toward the other side.

According to the present invention, it is possible to reduce the cost of the hinge mechanism.

(a) is an overall schematic diagram showing a printer according to the present embodiment, and (b) is a schematic diagram showing an image forming engine. FIG. 2 is a perspective view showing the image reading device with the ADF opened according to the present embodiment. (a) is a schematic cross-sectional view showing a state in which the ADF is closed without bending. (b) is a schematic cross-sectional view showing a state in which the ADF is bent and the front abutting portion abuts against the image reading unit. (c) is a schematic cross-sectional view showing a state in which the ADF is bent and the front abutting portion and the back abutting portion abut against the image reading unit. FIG. 2 is an exploded perspective view showing the hinge mechanism according to the present embodiment. FIG. 3 is a sectional view showing a hinge mechanism according to the present embodiment. FIG. 3 is a diagram showing the relationship between moment and torque with respect to the opening/closing angle of the hinge mechanism according to the present embodiment. (a) is a side view showing the hinge mechanism in a state where the ADF is opened. (b) is a side view showing the hinge mechanism in a state where the ADF is closed without bending. (c) is a side view showing the hinge mechanism in a state where the ADF is bent and the front abutment part abuts against the image reading unit. (d) is a side view showing the hinge mechanism in a state where the ADF is bent and the front abutment part and the back abutment part abut against the image reading unit. (a) is a schematic cross-sectional view showing the document reading device in a state where a thick document is set on the document table glass and opened at an angle with a large hinge torque. (b) is a side view showing the hinge mechanism in the state of FIG. 8(a). (c) is a sectional view showing the hinge mechanism in the state of FIG. 8(a). (a) is a schematic cross-sectional view showing the document reading device in a state where a thick document is set on the document table glass and the ADF is closed. (b) is a side view showing the hinge mechanism in the state of FIG. 9(a). (c) is a sectional view showing the hinge mechanism in the state of FIG. 9(a).

[overall structure]
The present embodiment will be described below with reference to the drawings. Printer 100 as an image forming apparatus according to this embodiment is an electrophotographic laser beam printer. As shown in FIG. 1A, the printer 100 includes a printer main body 70 and a document reading device 10 mounted on the upper part of the printer main body 70. Note that in the following, sheets include not only plain paper but also special papers such as cardboard and coated paper, recording materials with special shapes such as envelopes and index papers, and plastic films and cloth for overhead projectors. A manuscript is also an example of a sheet.

The printer main body 70 includes an image forming engine 60 as an image forming section therein. The image forming engine 60 includes an image forming unit PU as an electrophotographic image forming means and a fixing device 67, as shown in FIG. 1(b). When the start of the image forming operation is instructed, the photosensitive drum 61, which is a photosensitive member, rotates, and the surface of the drum is uniformly charged by the charging device 62. Then, the exposure device 63 modulates and outputs a laser beam based on the image data transmitted from the original reading device 10 as an image reading means or an external computer, and scans the surface of the photosensitive drum 61 to absorb the electrostatic latent light. form an image. This electrostatic latent image is visualized (developed) by toner supplied from the developing device 64 and becomes a toner image.

In parallel with such an image forming operation, a feeding operation is performed in which sheets stacked in a cassette or a manual feed tray (not shown) are fed toward the image forming engine 60. The fed sheet is conveyed in accordance with the progress of the image forming operation by the image forming unit PU. The toner image carried on the photosensitive drum 61 is then transferred onto a sheet by a transfer roller 65. The toner remaining on the photosensitive drum 61 after the toner image transfer is collected by a cleaning device 66. The sheet onto which the unfixed toner image has been transferred is transferred to the fixing device 67, where it is held between a pair of rollers and heated and pressurized. The sheet on which the image is fixed by melting and fixing the toner to the sheet is discharged by a discharge means such as a discharge roller.

[Original reading device]
Next, the document reading device 10 will be described in detail. As shown in FIG. 1A, the document reading device 10 includes an ADF (automatic document feeder) 20 that feeds documents stacked on a document tray 121 and ejects them onto an ejection tray 122, and an ADF (automatic document feeder) 20 that feeds documents stacked on a document tray 121 and discharges the documents onto an output tray 122. and an image reading unit 40 that reads the image. That is, the ADF 20 conveys a sheet as a document to the image reading unit 40. The image reading unit 40 includes a reading section 30 that reads an image on the front surface of a document. As will be described in detail later, the ADF 20 is connected to the image reading unit by the hinge mechanism 3 (see FIG. 2) so that the platen glass 201 and document table glass 203, which are translucent members that transmit light, can be opened. 40 so as to be rotatable. Further, a document, which is an example of a sheet, may be a blank sheet, or may have an image formed on one or both sides.

The ADF 20 includes a pickup roller 101, a separation drive roller 102 and a separation driven roller 103 that constitute a separation roller pair, a registration roller pair 104, conveyance roller pairs 105, 106, 108, and a discharge roller pair 109. ing. The ADF 20 also includes a reading section 29 for reading an image on the back side of the document.

On the other hand, the image reading unit 40 includes a platen glass 201, a jump table 202, a document table glass 203, and a reading section 30 for reading the surface of the document.

The document reading device 10 has a continuous reading mode in which the document image is scanned while the document loaded on the document tray 121 is fed by the ADF 20, and a fixed reading mode in which the document placed on the document platen glass 203 is scanned. , it is possible to read images from a document. Skim reading mode is selected when a document presence/absence detection sensor (not shown) detects a document stacked on document tray 121, or when a user explicitly instructs it through the operation panel of printer main body 70 or the like.

When the skimming mode is executed, the pickup roller 101 descends and comes into contact with the uppermost document set on the document tray 121. Then, the originals are fed by a pickup roller 101 and separated into sheets one by one in a separation nip serving as separation means formed by a separation drive roller 102 and a separation driven roller 103. A torque limiter is arranged in the rotational support structure of the separation driven roller 103, and when the number of fed documents is one, the separation driven roller 103 follows the separation driving roller 102, and when the number of fed documents is two. It does not rotate when there are more than one sheet. Therefore, the documents can be separated one by one. Note that driving in the direction opposite to the sheet feeding direction may be input to the separation driven roller 103.

The leading edge of the transported document abuts against the stopped registration roller pair 104, and the skew of the document is corrected. The document whose skew has been corrected is conveyed by a pair of registration rollers 104 and conveyed by pairs of conveyance rollers 105, 106, and 108 so as to pass over the surface of the platen glass 201, and then moved to the reading position of the reading unit 29. conveyed as if passing through. A platen guide 107 is arranged opposite to the platen glass 201, and the platen guide 107 guides the document passing through the platen glass 201 so that it does not float away from the platen glass 201.

The image on the front side of the original is read by the reading unit 30 via the platen glass 201, and the image on the back side of the original is read by the reading unit 29. Image information photoelectrically converted by light receiving elements of line sensors (not shown) of these reading units 30 and 29 is transferred to a control unit 80 (see FIG. 1(a)). The document that has passed through the platen glass 201 is guided by the jump table 202 to a pair of transport rollers 108, passes through a reading section 29, and is discharged onto a discharge tray 122 by a pair of discharge rollers 109.

On the other hand, the fixed reading mode is selected when the apparatus detects a document placed on the document table glass 203 or when the user explicitly instructs it through the operation panel of the printer body 70 or the like. In this case, the original on the original platen glass 203 does not move, and the reading unit 30 moves along the original platen glass 203 to scan the original. Similarly, image information photoelectrically converted by a light receiving element of a line sensor (not shown) of the reading section 30 is transferred to the control section 80 (see FIG. 1(a)).

[Positional relationship between ADF and image reading unit]
Next, FIG. 2 shows the arrangement of the hinge mechanism 3 and the structure of the abutting part 21 and the pressure plate 22, which are provided in the ADF 20 and serve as an abutting part that abuts the image reading unit 40 when the ADF 20 is closed. Explain using. FIG. 2 is a perspective view showing the image reading device according to the present embodiment with the ADF opened.

As shown in FIG. 2, in the document reading device 10 according to the present embodiment, left and right hinge mechanisms 3L and 3R (hereinafter simply referred to as "hinge mechanism 3" when there is no need to distinguish) are connected to the image reading unit 40. It is installed to support the ADF 20 so that it can be opened and closed. These left and right hinge mechanisms 3L and 3R are installed in the image reading unit 40 at two different positions in the X direction, which is the left and right direction of the printer 100. The left and right hinge mechanisms 3L and 3R are designed to have different sizes depending on the difference in weight of the ADF 20 in the left and right direction.

The abutting portion 21 has an abutting portion 21a as a first abutting portion that abuts the front end of the platen glass 201 in the Y direction, which is the front-rear direction of the printer 100, when the ADF 20 is closed. . The abutting portion 21 also includes an abutting portion 21b as a second abutting portion that abuts against the rear end of the platen glass 201 in the Y direction, which is the front-rear direction of the printer 100, when the ADF 20 is closed. are doing. The abutting portion 21a is disposed at a position farther from the hinge mechanism 3 than the region of the conveyance path where the sheet is conveyed in the width direction perpendicular to the sheet conveyance direction. On the other hand, the abutment portion 21b is disposed at a position closer to the hinge mechanism 3 in the width direction than the region of the conveyance path where the sheet is conveyed. These abutting portions 21a and 21b abut against both ends of the platen glass 201, so that in the above-described skimming mode, there is a gap between the platen glass 201, the jump table 202 (see FIG. 1(a)), and the platen guide 107. , a conveyance path through which the original passes is formed.

That is, the platen glass 201 and the jump table 202, together with the platen guide 107 of the ADF 20, are configured as part of a conveyance guide that guides the document. However, while the other conveyance guides that guide the document in the ADF 20 are configured within the same ADF 20, the platen glass 201 and the jump table 202 are components on the image reading unit 40 side. Therefore, by abutting the abutting portions 21a and 21b against both ends of the platen glass 201, the relative position between the image reading unit 40 and the ADF 20 is maintained appropriately, and the conveyance path of other parts of the ADF 20 and the platen glass 201 are consistency with the transport path is maintained.

Note that these abutting portions 21a and 21b may abut against a frame portion 205 (see FIG. 3(a)) surrounding the platen glass 201. These abutting portions 21a and 21b may come into contact with the frame portion 205 due to the influence of component tolerances or due to balance adjustment (equalization) as will be described in detail later. However, the surface of the frame portion 205 is formed substantially on the same plane as the surface of the platen glass 201, and even if the abutting portions 21a and 21b abut against the frame portion 205, they will abut against the surface of the platen glass 201. It is synonymous with being guessed. In other words, even if the abutting sections 21a and 21b abut against the frame section 205, the relative positions of the image reading unit 40 and the ADF 20 are maintained appropriately, and consistency with other portions of the conveyance path is maintained.

Further, the ADF 20 is provided with a pressure plate 22 that is pressed against the document table glass 203 when the ADF 20 is closed. The pressure plate 22 is formed in a rectangular shape having a front side 22a at the front of the printer 100, a rear side 22b at the rear, a left side 22c at the left side, and a right side 22d at the right side. One document table glass 203 is provided with a vertical size index 206 and a horizontal size index 207 that indicate the size of the document to be set. The pressure plate 22 is arranged so that when the ADF 20 is closed, the left side 22c does not overlap the vertical size index 206 and is close to the vertical size index 206 with as little gap as possible, and the rear side 22b does not overlap the horizontal size index 207 and is arranged as close as possible to the vertical size index 206. They are placed close together without any gaps. In addition, when the abutment of the abutting portion 21b is adjusted by equalization, which will be described in detail later, the rear side 22b is adjusted to be close to the horizontal size index 207.

[Configuration of hinge mechanism 3]
Next, the configuration of the hinge mechanism 3 according to this embodiment will be explained using FIGS. 4 to 6. FIG. 4 is an exploded perspective view showing the hinge mechanism according to this embodiment. FIG. 5 is a sectional view showing the hinge mechanism according to this embodiment. FIG. 6 is a diagram showing the relationship between moment and torque with respect to the opening/closing angle of the hinge mechanism according to the present embodiment. For convenience of explanation, the directions used in explaining the structure of the hinge mechanism 3 are the left-right direction (X direction), the front-back direction (Y direction), and the up-down direction (Z direction) of the printer 100, assuming that the hinge mechanism 3 is fixed to the printer 100. (direction).

As shown in FIGS. 4 and 5, the hinge mechanism 3 roughly includes a fixed member 31 as a first member, an opening/closing member 32 as a second member, and a first rotating member 33 as a third member. , and a second rotating member 34 as a fourth member. The hinge mechanism 3 also includes a hinge rotation shaft 35 as a first shaft supported by the fixed member 31, a book rotation shaft 36 as a second shaft supported by the opening/closing member 32, and a first rotation member. It has a lift shaft 37 as a third shaft supported by 33. Further, as shown in FIG. 5, the hinge mechanism 3 includes a first biasing portion F1 that applies a torque in the direction of opening the ADF 20 according to the rotation angle of the ADF 20 with respect to the image reading unit 40. The hinge mechanism 3 includes a second biasing portion F2 that applies torque to the second rotating member 34 in a direction in which the abutting portion 21 and the pressure plate 22 are parallel to the surface of the platen glass 201. ing.

Specifically, as shown in FIG. 5, the fixing member 31 includes a bottom plate 31c fixed to the image reading unit 40, a pair of side plates 31d formed upward from the bottom plate 31c, and a bottom plate 31d. It has a back plate 31e formed upward from 31c. That is, the fixing member 31 is formed into a box shape with an open top and front by the bottom plate 31c, the side plates 31d, and the back plate 31e. Further, a through hole 31a and a through hole 31b are formed in the pair of side plates 31d, and the hinge rotation shaft 35 is inserted into the through hole 31a so that its axial direction is in the left-right direction. It is supported by Further, a cam pin 31A serving as a pressure receiving member is fitted and fixedly supported in the through hole 31b so that its longitudinal direction is in the left-right direction.

As shown in FIGS. 4 and 5, the opening/closing member 32 includes a top plate 32c and a pair of side plates 32d formed downward from the top plate 32c. That is, the opening/closing member 32 is formed in a U-shape so as to cover the fixing member 31 from above. In addition, a through hole 32a on the rear side and a through hole 32b on the front side are formed in the pair of side plates 32d, and the through hole 32a has a hinge inserted into the through hole 31a of the fixing member 31. The shaft 35 is fitted and fixedly supported so as to straddle the left and right direction. Furthermore, the book rotating shaft 36 is inserted and supported in the through hole 32b so that its axial direction is in the left-right direction. The book rotation axis 36 is therefore arranged parallel to the hinge rotation axis 35 at different positions. The opening/closing member 32 is configured to be rotatable relative to the fixed member 31 about the center CT1 of the hinge rotation shaft 35 as a fulcrum.

As shown in FIGS. 4 and 5, the first rotating member 33 includes a top plate 33c as a second plate portion, and a pair of side plates as first plate portions formed downward from the top plate 33c. 33d. In other words, the first rotating member 33 is arranged on a plane perpendicular to the lift shaft 37 and engages with the lift shaft 37, and a plate-shaped side plate 33d arranged on a plane perpendicular to the side plate 33d. It has a plate-shaped top plate 33c. That is, the first rotating member 33 is formed in a U-shape so as to cover the opening/closing member 32 from above. Further, the pair of side plates 33d are formed with a through hole 33a on the front side and a through hole 33b on the lower side thereof, and the through hole 33a has a book hole inserted into the through hole 32a of the opening/closing member 32. The moving shaft 36 is fitted and fixedly supported so as to straddle the left and right direction. Further, the lift shaft 37 is inserted and supported in the through hole 33b so that its axial direction is in the left-right direction. The lift shafts 37 are therefore arranged parallel to the book rotation shaft 36 at different positions. The first rotating member 33 is configured to be rotatable relative to the opening/closing member 32 about the center CT2 of the book rotating shaft 36 as a fulcrum.

Note that the top plate 33c of the first rotating member 33 has a fixing hole 33ca as a fixing part to which a stepped screw 38 to which a spring 39 as a second spring in the second biasing part F2 to be described later is fixed is fixed. is formed. Further, the fixing hole 33ca in the top plate 33c constitutes a pressure receiving portion 33p as a first pressure receiving portion that receives the urging force of the spring 39.

As shown in FIGS. 4 and 5, the second rotating member 34 includes a top plate 34c as a fourth plate portion, and a pair of side plates as third plate portions formed downward from the top plate 34c. 34d. In other words, the second rotating member 34 has a plate-shaped side plate 34d arranged on a plane orthogonal to the lift shaft 37 and engaged with the lift shaft 37, and a plate-shaped side plate 34d arranged on a plane orthogonal to the side plate 34d. It has a plate-shaped top plate 34c. That is, the second rotating member 34 is formed in a U-shape so as to cover the first rotating member 33 from above.

Further, the pair of side plates 34d are formed with a long hole 34a penetrating forward and a through hole 34b below the long hole 34a. A book rotation shaft 36 inserted into the through hole 33a of the rotation member 33 is arranged to penetrate therethrough. That is, the long hole 34a is a long hole formed to be elongated in the circumferential direction around the lift shaft 37. The elongated hole 34a allows the second rotating member 34 to rotate when the second rotating member 34 rotates in the direction in which the abutting portions 21a and 21b are parallel to the platen glass 201, as will be described in detail later. It is formed as a so-called escape hole that allows relative movement with the lift shaft 37.

Further, the chamfered end of the lift shaft 37 is fitted into the D-shaped through-hole 34b, and is fitted and fixedly supported so as to straddle the left-right direction of the through-hole 34b. There is. The second rotating member 34 is configured to be rotatable relative to the first rotating member 33 about the center CT3 of the lift shaft 37 as a fulcrum.

Further, the side plate 34d has a first support plate portion 34e formed with a screw hole 34f and a second support plate portion 34g formed with two screw holes 34h, which are integrally bent and formed. The case 20C of the ADF 20 or the frame (not shown) is fixed to the first support plate part 34e and the second support plate part 34g by screws (not shown) being screwed into the screw holes 34f and 34h. Ru. As a result, the second rotating member 34 and the ADF 20 are integrated, and the ADF 20 is opened and closed by the angle of the second rotating member 34.

Note that the top plate 34c of the second rotating member 34 is formed with a through hole 34ca as a hole portion through which a shaft portion 38c of a spring 39 in a second biasing portion F2 to be described later is disposed. Further, the periphery of the through hole 34ca in the top plate 34c constitutes a pressure receiving portion 34p serving as a second pressure receiving portion or the other end support portion that receives the biasing force of the spring 39.

The second biasing portion F2 includes a stepped screw 38 as a support member that supports the spring 39, and a spring 39 that is a coil spring as a second spring into which the stepped screw 38 is inserted. has been done. The stepped screw 38 has a head 38a serving as one end support, a male threaded portion 38b, and a shaft portion 38c connecting them, and is inserted through the through hole 34ca while the male threaded portion 38b is It is screwed into a female thread formed in the fixing hole 33ca. As a result, one end 39a of the spring 39 is brought into contact with the pressure receiving part 34p of the top plate 34c of the second rotating member 34, and the other end 39b of the spring 39 is brought into contact with the head 38a of the stepped screw 38. Then, a spring 39 is provided. Therefore, one biasing force of the spring 39 is received by the pressure receiving portion 34p, and one biasing force of the spring 39 is received by the pressure receiving portion 33p via the head 38a of the stepped screw 38.

On the other hand, the first biasing portion F1 includes a spring 53 which is a coil spring as a first spring, a first slider 51 as a first support member and a second support member arranged at both ends of the spring 53, respectively. The second slider 52 is configured to include a second slider 52. The first slider 51 abuts and supports one end 53a of the spring 53, and is arranged to be slidable relative to the top plate 32c and side plate 32d (see FIG. 4) of the opening/closing member 32. Further, the first slider 51 has an end surface 51a opposite to the spring 53 formed as a first engaging portion that abuts and engages with the cam pin 31A. That is, the biasing force of the spring 53 toward one side is received by the fixed member 31 via the cam pin 31A.

Similarly, the second slider 52 is arranged to abut and support the other end 53b of the spring 53 and to be slidable relative to the top plate 32c and side plate 32d (see FIG. 4) of the opening/closing member 32. Further, the second slider 52 has an end surface 52 a opposite to the spring 53 formed as a second engaging portion that engages and abuts the lift shaft 37 . That is, the biasing force of the spring 53 toward the other side is received by the lift shaft 37.

Here, the application of torque by the first urging portion F1 configured in this way will be explained. When the opening and closing member 32 mainly opens and closes relative to the fixed member 31 as the ADF 20 opens and closes, the cam pin 31A is fixed to the fixed member 31, while the first slider 51 moves along with the opening and closing member 32 to the hinge rotation axis. 35 center CT1 as a fulcrum. As a result, the spring 53 expands and contracts in accordance with the shape of the end surface 51a that abuts and engages with the cam pin 31A. That is, since the book rotation shaft 36 is positioned relative to the opening/closing member 32, the biasing force of the spring 53 applied to the lift shaft 37, which is rotatable about the center CT2 of the book rotation shaft 36, is Change.

The opening/closing angle An1 (see FIG. 5) is the rotation angle of the opening/closing member 32 with respect to the fixed member 31 with the hinge rotation shaft 35 as a fulcrum. Further, FIG. 6 shows the relationship between the magnitude of the moment M in the direction in which the ADF 20 closes with respect to the image reading unit 40 and the magnitude of the torque T applied in the opening direction by the first biasing portion F1 with respect to the opening/closing angle An1. It shows. That is, when the opening/closing angle An1 is the angle An1a (for example, 10 degrees to 20 degrees), the torque T by the first biasing portion F1 has a characteristic that it reaches its peak.

Therefore, when the opening/closing angle An1 is 10 degrees or less, that is, when the ADF 20 is closed to 10 degrees or less, the moment M due to the weight of the ADF 20 becomes larger than the torque T due to the first biasing portion F1 of the hinge mechanism 3. Constructed to close under its own weight. Furthermore, in a state where the opening/closing angle An1 is 20 degrees or more, the torque T by the first biasing part F1 of the hinge mechanism 3 has a strength equal to or greater than the moment M due to its own weight, and the ADF 20 can be maintained in an open state. It is designed to be easy to open and close.

[About deflection according to ADF rigidity]
Next, FIGS. 3(a) and 3(b) show the deflection according to the rigidity of the ADF 20 that occurs when opening and closing the ADF 20, and the abutting state between the abutting part 21 and the platen glass 201 (including the frame part 205). , and FIG. 3(c). FIG. 3(a) is a schematic cross-sectional view showing a state in which the ADF is closed without bending. FIG. 3(b) is a schematic cross-sectional view showing a state in which the ADF is bent and the front abutting portion abuts against the image reading unit. FIG. 3(c) is a schematic cross-sectional view showing a state in which the ADF is bent and the front abutting portion and the back abutting portion abut against the image reading unit. Note that, as described above, the abutting portion 21 may abut against the frame portion 205, but this is synonymous with the case where the abutting portion 21 abuts against the platen glass 201, and the following description will be made assuming that the abutting portion 21 abuts against the platen glass 201.

As shown in FIG. 3(a), if the frame structure of the ADF 20 (not shown) has high rigidity and the case 20C of the ADF 20 does not bend, the abutting portions 21a and 21b will not bend when the ADF 20 is closed. It is balanced against the platen glass 201. However, as shown in FIG. 3(b), for example, in an ADF 20 configured with a frame structure made of resin in order to reduce weight and cost, the case 20C bends due to its own weight due to its low rigidity. Therefore, when the ADF 20 is closed with respect to the image reading unit 40, the front part of the ADF 20 hangs down, and the front abutment part 21a abuts the platen glass 201 before the rear abutment part 21b.

Further, as described above, the hinge mechanism 3 is given a torque T (see FIG. 6) by the first biasing portion F1 in the direction in which the ADF 20 opens so that the ADF 20 can be opened and closed easily. A force Ft acts on the lift shaft 37. Therefore, for example, if the second biasing part F2 is not provided, even if the ADF 20 is closed, the abutment part 21b will not abut against the platen glass 201 and will float.

In the hinge mechanism 3 according to the present embodiment, as shown in FIG. Then, the pressure receiving portion 34p (see FIG. 4) of the second rotating member 34 is pressed with a force Fs. Thereby, the rear abutment part 21b can be abutted against the platen glass 201, that is, the balance between the front abutment part 21a and the rear abutment part 21b is adjusted, and the gap between the platen glass 201 and the ADF 20 is adjusted. The document transport path is formed with high precision. In this embodiment, this adjustment of the degree of balance is referred to as equalization, and the details of equalization of the hinge mechanism 3 will be described below with reference to FIG. 7.

[Equalization of hinge mechanism]
Next, regarding the equalization of the abutting portions 21a and 21b against the platen glass 201 by the hinge mechanism 3, referring to FIGS. 3(a), 3(b), and 3(c), FIGS. 7(b), FIG. 7(c), and FIG. 7(d). FIG. 7A is a side view showing the hinge mechanism when the ADF is open. FIG. 7(b) is a side view showing the hinge mechanism in a state where the ADF is closed without bending. FIG. 7C is a side view showing the hinge mechanism in a state where the ADF is bent and the front abutment part abuts against the image reading unit. FIG. 7D is a side view showing the hinge mechanism in a state where the ADF is bent and the front abutting portion and the back abutting portion abut against the image reading unit.

In addition, regarding the angle of each part, virtual line, each axis, and the position of the abutting part, which will be explained using FIGS. 7(a), 7(b), 7(c), and 7(d), All will be explained as seen from the axial direction (X direction) of the hinge rotation shaft 35, the book rotation shaft 36, and the lift shaft 37.

As the ADF 20 is closed from the open state, the opening/closing angle An1 between the reference plane H31 on which the fixing member 31 is installed and the bottom surface H32 of the opening/closing member 32 becomes smaller, as shown in FIG. 7(a). Note that the bottom surface H32 is parallel to the center of the top plate 32c (see FIG. 4) and the spring 53 (see FIG. 5).

Here, FIG. 7B shows the hinge mechanism 3 in an ideal state where the ADF 20 is closed with respect to the image reading unit 40, where the case 20C of the ADF 20 does not bend as shown in FIG. 3A. As shown in FIG. 7B, when the ADF 20 is ideally closed, the bottom surface H32 of the opening/closing member 32 is located parallel to the reference plane H31. Then, the second rotating member 34 to which the ADF 20 is fixed is also positioned in parallel, and the rear abutment portion 21b is also abutted against the platen glass 201. Further, in this state, a gap d1 is formed on the rear side between the second rotating member 34 and the first rotating member 33. Further, in this state, the book rotation shaft 36 is in contact with the rear end 34aa of the long hole 34a of the second rotation member 34.

In this state, the angle formed by the virtual line L1 connecting the hinge rotation axis 35 and the lift axis 37 with respect to the reference plane H1 is defined as an angle An2. Further, the angle formed by the virtual line L2 connecting the lift shaft 37 and the tip 22ba of the abutting portion 21b (the point of contact with the platen glass 201) is defined as an angle An3. Note that the tip 22ba of the abutting portion 21b that contacts the platen glass 201 constitutes the end on the hinge mechanism 3 side of the abutting portions 21a and 22b, which are abutting portions that abut the image reading unit 40. There is.

Due to the structure of the hinge mechanism 3 described above, parts of the hinge mechanism 3 other than the fixing member 31, such as the lift shaft 37 and the abutting portion 21b, and the ADF 20 rotate about the hinge rotation shaft 35 as a fulcrum. Therefore, the lift shaft 37 rotates on a rotation locus D35 having a radius around the hinge rotation axis 35. Further, the second rotating member 34 rotates about the lift shaft 37 as a fulcrum. Therefore, the rear abutment portion 21b provided on the ADF 20 fixed to the second rotation member 34 rotates on a rotation locus D37 having a radius around the lift shaft 37.

As described above, in reality, due to the low rigidity of the frame of the ADF 20, the front (-Y direction side) of the ADF 20 becomes sagging as shown in FIG. 3(c). Then, the front abutment part 21a first comes into contact with the platen glass 201, and at this moment, the rear abutment part 21b is in a state floating from the platen glass 201.

At this time, the hinge mechanism 3 is in the state shown in FIG. 7(c), and the opening/closing member 32 is slightly opened at the opening/closing angle An1b compared to the ideal state shown in FIG. 7(b). The contact portion 21b is floating away from the platen glass 201 by a distance d2.

In addition, in this state, as shown in FIG. 3(b), the dead weight W of the ADF 20 acts at the center of gravity located at a distance yw1 from the front abutting portion 21a, and a moment in the direction of closing the ADF 20 acts. do. In addition to this, a force Ft is applied to the lift shaft 37 due to the torque generated by the first urging portion F1 of the hinge mechanism 3 in the direction in which the ADF 20 is opened. It is assumed that the lift shaft 37 is located at a distance yt1 from the front abutting portion 21a. As described above, the spring 39 in the second biasing portion F2 applies a force Fs that presses the second rotating member 34 toward the first rotating member 33 at a distance ys1 from the front abutment portion 21a. Acts on position.

The following equation (1) shows the condition under which the sum of the force Fs caused by the spring 39 and the moment caused by the dead weight W of the ADF 20 is larger than the moment generated by the force Ft caused by the torque of the first biasing portion F1 of the hinge mechanism 3.
Fs・ys1+W・yw1>Ft・yt1 (1)

When the condition of this formula (1) is satisfied, the lift shaft 37 on which the torque T of the first biasing portion F1 is generated is pushed down, that is, the opening/closing member 32 is closed, and the rear abutment portion 21b of the ADF 20 is pushed down. It is lowered so as to come into contact with the platen glass 201.

That is, in the hinge mechanism 3 shown in FIG. 7(c), the lift shaft 37 rotates clockwise in the figure around the hinge rotation shaft 35 together with the opening/closing member 32, the first rotation member 33, and the second rotation member 34. Rotate to. Further, since the second rotating member 34 is pressed by the spring 39, it rotates counterclockwise in the figure about the lift shaft 37 toward the first rotating member 33, and as shown in FIG. 7(d). Transition to the state shown. As a result, in the state shown in FIG. 7(d), the gap d1 on the rear side between the second rotating member 34 and the first rotating member 33 is larger than the gap d1 in the state shown in FIG. 7(b). It's getting smaller.

FIG. 7(d) shows the state after equalization (balance adjustment). Compare this with the ideal closed state of the ADF 20 shown in FIG. 7(b). Then, the angle An2 formed by the hinge rotation axis 35 and the lift axis 37 with respect to the reference plane H31 is such that the lift axis 37 rotates downward on the rotation trajectory D35 by an angle ΔAn2 with respect to the angle An2 in the ideal state. are doing. That is, the lift shaft 37 is moving slightly in the +Y direction, which is the front-back direction. The amount of movement ΔY1 of the lift shaft 37 in the Y direction is expressed by the following equation (2).
ΔY1=r1・cosAn2−r1・cos(An2+ΔAn2) (2)

Note that the lift shaft 37 is located in the -Z direction, which is the upper direction, and in the -Y direction, which is the front direction, with respect to the hinge rotation shaft 35, and the angle An2 and the angle An2+ΔAn2 are both 90 degrees or less. Therefore, the movement amount ΔY1 is positive (backwards).

In addition, the smaller angle An3 formed by the virtual line L3 connecting the lift shaft 37 and the rear abutting portion 21b with respect to the reference plane H31 is such that the ADF 20 is in the ideal closed state shown in FIG. 7(b). On the other hand, it rotates upward about the lift shaft 37 by an angle ΔAn3. In other words, the rear abutting portion 21b moves slightly in the -Y direction, which is the front direction. The amount of movement ΔY2 of the abutting portion 21b in the Y direction is expressed by the following equation (3).
ΔY2=r2・cosAN3−r2・cos(An3−ΔAn3) (3)

Note that the rear abutting portion 21b is located in the -Z direction, which is the downward direction, and in the -Y direction, which is the front direction, with respect to the lift shaft 37. Further, since the angle An3 and the angle An3-ΔAn3 are both 90 degrees or less, the movement amount ΔY2 is negative (in the forward direction). In other words, the abutting portion 21b is moving in the front direction (-Y direction), which is the opposite direction to the front-back direction of the lift shaft 37.

However, when the lift shaft 37 moves downward along the rotation trajectory D35 around the hinge rotation axis 35, the abutting portion 21b acts as a component of the ADF 20 at the same time as the second rotation member 34. Move the top down. Therefore, the movement amount ΔY1 in the above equation (2) and the movement amount ΔY2 in the above equation (3) cancel each other out, and the movement amount in the Y direction becomes minute.

[Amount of movement of the abutment part during equalization due to lift axis arrangement]
Next, the amount of movement ΔY2 of the abutment portion 21b during equalization due to the arrangement of the lift shaft 37 in the hinge mechanism 3 will be explained. In the ADF described in Japanese Patent No. 3917097, the upper stay (43) rotates about the fulcrum (f3) with respect to the rotating end member (34), thereby moving the ADF relative to the document reading unit. The balance is adjustable when closed. However, the fulcrum (f3) is on the opposite side of the fulcrum (f1) with respect to the fulcrum (f2), that is, the fulcrum (f3) is located forward and above.

Comparing this with the hinge mechanism 3 of this embodiment, it is found that the lift shaft 37 shown in FIG. In other words, it is located at the upper right in the figure. In this case, the rotation locus D37 of the abutting portion 21b that rotates around the lift shaft 37 approaches the horizontal direction (front-back direction) near the surface of the platen glass 201. Therefore, when the second rotating member 34 rotates around the lift shaft 37 during equalization, the amount of movement ΔY2 in the front-rear direction increases, that is, the conveyance path formed between the ADF 20 and the platen glass 201 moves rearward. This will result in misalignment. Further, the hinge mechanism 3 is arranged at a plurality of locations (in this embodiment, two locations (see FIG. 2)) in the left-right direction of the printer 100, for example, and the amount of flexure due to the rigidity differs due to the difference in the weight balance of the ADF 20 in the left-right direction. . Therefore, if the amount of movement ΔY2 in the front-rear direction is large, the difference in the amount of movement ΔY2 due to equalization in the hinge mechanisms 3 at a plurality of locations becomes large, which causes the problem of skewing of the document.

Therefore, in this embodiment, the lift shaft 37 is arranged below the book rotation shaft 36. Note that the lift shaft 37 is arranged below the book rotation shaft 36 on the side of the fixed member 31, but above the imaginary line L2 connecting the hinge rotation shaft 35 and the abutting portion 21b. has been done.

Specifically, as shown in FIG. 7D, it is assumed that the ADF 20 is closed with respect to the image reading unit 40 and the abutting portion 21b is in contact with the image reading unit 40 in the closed state. In this closed state, a line connecting the contact point of the rear abutting part 21b, which is the end of the abutting part 21 on the side of the hinge mechanism 3, and the center of the lift shaft 37 is a first imaginary line L3. shall be. Further, a line connecting the abutting portion 21b and the center of the book rotation shaft 36 is defined as a second virtual line L4. The lift shaft 37 is arranged so that the smaller angle An4 between the surface H201 of the platen glass 201 and the imaginary line L3 is smaller than the smaller angle An5 between the surface H201 of the platen glass 201 and the imaginary line L4. Place it in

In other words, when the ADF 20 is in the closed state, the lift shaft 37 is located on the side closer to the surface H201 of the platen glass 201 than the book rotation shaft 36, and between the hinge rotation shaft 35 and the book rotation shaft 36. placed in between. In other words, if the line connecting the contact point of the abutment portion 21b and the center of the hinge rotation shaft 35 is the virtual line L2 as the third virtual line (see FIG. 7(b)), the lift shaft 37 It is arranged on the side where the imaginary line L2 passes with respect to the rotation axis 36. In other words, if the line connecting the center of the hinge rotation shaft 35 and the center of the lift shaft 37 is the virtual line L1 as the fourth virtual line, the lift shaft 37 is located above the virtual line L2 and above the virtual line L2. They are arranged so that an angle An6 between L3 and the virtual line L1 is 90 degrees or more.

By arranging the lift shaft 37 in the position described above in the hinge mechanism 3, the rotation locus D37 of the abutment portion 21b that rotates around the lift shaft 37 is vertically close to the surface of the platen glass 201. approach. Therefore, even if the second rotating member 34 rotates around the lift shaft 37 during equalization, the amount of movement of the abutting portion 21b in the front-rear direction is smaller than when the lift shaft 37 is above the book rotating shaft 36. ΔY2 can be reduced. Therefore, the skew of the document in the skim reading mode can be reduced, and the quality of the read image can be improved.

In addition, in the above description, the case where the front abutment part 21a and the rear abutment part 21b of the abutment part 21 butt against the platen glass 201 in parallel has been described as equalization. However, the present invention is not limited to this, and the same applies to the case where the pressure plate 22 as a contact portion is brought into contact with the document table glass 203 in parallel. That is, the front side 22a and the rear side 22b of the pressure plate 22 have the same positional relationship as the front abutment part 21a and the rear abutment part 21b. In other words, by arranging the lift shaft 37 as described above, when the rear side 22b of the pressure plate 22 is brought into contact with the document table glass 203, the amount of movement ΔY2 of the rear side 22b in the front-rear direction can be reduced. This allows the pressure plate 22 to press the original parallelly and accurately against the original platen glass 203.

[Book Equalize]
Next, FIGS. 8(a) and 8(b) show the case where the ADF 20 is closed and book equalization is performed when a thick original Da such as a dictionary is placed on the original platen glass 203 and the fixed reading mode is executed. , FIG. 8(c), FIG. 9(a), FIG. 9(b), and FIG. 9(c). FIG. 8A is a schematic cross-sectional view showing the document reading device in a state where a thick document is set on the document table glass and opened at an angle with a large hinge torque. FIG. 8(b) is a side view showing the hinge mechanism in the state of FIG. 8(a). FIG. 8(c) is a sectional view showing the hinge mechanism in the state of FIG. 8(a). FIG. 9A is a schematic cross-sectional view showing the document reading device in a state where a thick document is set on the document table glass and the ADF is closed. FIG. 9(b) is a side view showing the hinge mechanism in the state of FIG. 9(a). FIG. 9(c) is a sectional view showing the hinge mechanism in the state of FIG. 9(a).

Note that book equalization means that, as shown in FIG. 9(a), this is an operation in which the ADF 20 is adjusted to balance. The operation during book equalization will be explained below.

The original placed on the original platen glass 203 can be read by scanning in the Y direction while moving the reading unit 30 (see FIG. 1) in the left-right direction, that is, the X direction, in the fixed reading mode. In particular, if the document is thin, by closing the ADF 20 with respect to the image reading unit 40, the document can be pressed against the document table glass 203 by the pressure plate 22 of the ADF 20.

However, as shown in FIG. 8A, if the document Da placed on the document table glass 203 is a thick book such as a dictionary, the document Da placed on the document table glass 203 is placed with its open side facing the document table glass 203. I will put it there. Since the gutter area at the center of the two-page spread tends to rise, making it difficult to focus or becoming dark, it is particularly preferable to hold the ADF 20 parallel to the original platen glass 203 in this area as a whole.

FIG. 8(b) shows the hinge mechanism 3 when the ADF 20 is in the state shown in FIG. 8(a). The opening/closing angle state of the hinge mechanism 3 is near the angle An1a in FIG. 6, where the torque T in the direction of opening the ADF 20 by the first biasing portion F1 is the largest, and the moment M due to the self-weight of the ADF 20 is in the vicinity of the angle An1a in FIG. This is a slight decrease compared to the current state.

The force Fs by the spring 39 of the second biasing portion F2 and the dead weight W of the ADF 2 are in a seesaw-like state with respect to the lift shaft 37 (see FIG. 3(c)). Therefore, when the force Fs exerted by the spring 39 is stronger, the second rotating member 34 rotates relative to the first rotating member 33 about the lift shaft 37, and the book rotating shaft 36 rotates at the end of the elongated hole 34a. The portion 34aa is separated from the book rotation shaft 36.

FIG. 8(c) is a sectional view of the hinge mechanism 3 in the states of FIGS. 8(a) and 8(b). The first rotation member 33 is configured to be rotatable about the book rotation shaft 36 as a fulcrum, and in this state is pressed by the second slider 52 pressed by the spring 53 via the lift shaft 37 . Therefore, a counterclockwise moment in the figure acts on the first rotating member 33, and the top plate 33c abuts against the top plate 32c of the opening/closing member 32 at the rear end. Furthermore, inside the opening/closing member 32, the first slider 51 of the first biasing portion F1 is in contact with and engaged with the cam pin 31A, and the lift shaft 37 is in contact with the second slider 52, so that the spring The working length of 53 is length x1.

At this time, as described above, the end 34aa of the elongated hole 34a of the second rotation member 34 was in a state separated from the book rotation shaft 36, but by further applying the operating force FU, the second rotation member 34 The member 34 rotates about the lift shaft 37 as a fulcrum, and the end portion 34aa abuts against the book rotation shaft 36. Due to this contact, the first rotating member 33 and the second rotating member 34 become integrated, and the operating force FU is applied to the second slider by rotating the lift shaft 37 with the book rotating shaft 36 as a rotational fulcrum. A moment acts to compress the spring 52 and shorten the length of the spring 53.

As a result, the book-equalized state is as shown in FIG. 9(a). At this time, the entire document Da can be pressed vertically downward against the document table glass 203 by the balanced pressure plate 22 of the ADF 20 . On the other hand, since the restoring force FH by the spring 53 of the first biasing portion F1 strongly acts on the lift shaft 37, this state cannot be maintained unless the operating force FU is continuously applied.

FIG. 9(b) shows the hinge mechanism 3 when the ADF 20 is in the state shown in FIG. 9(a). The opening/closing member 32 is in an open state at an angle An1a with the hinge rotation shaft 35 as the fulcrum, but the first rotation member 33 and the second rotation member 34 are also rotated around the book rotation shaft 36 as the clock in the figure. rotate around. Thereby, the pressure plate 22 of the ADF 20 is set at an angle parallel to the document table glass 203, and the entire document Da is pressed uniformly.

The end 34aa of the elongated hole 34a of the second rotating member 34 maintains a state in contact with the book rotating shaft 36, and lifts the operating force FU applied to the front part of the ADF 20 from the second rotating member 34. It is transmitted to the shaft 37. As a result, the lift shaft 37 compresses and pushes the spring 53 of the first biasing portion F1, and the first rotating member 33 and the second rotating member 34 are integrally moved as shown in the figure using the book rotating shaft 36 as a fulcrum. The moment to rotate it clockwise is obtained.

In addition, since the end 34aa of the elongated hole 34a is in contact with the book rotation shaft 36, the second rotation member 34 cannot rotate clockwise in the figure using the lift shaft 37 as a fulcrum beyond this state. Therefore, the spring 39 of the second biasing portion F2 is not further compressed. This prevents the windings of the spring 39 from coming into close contact with each other, so there is no risk of the spring 39 becoming sagging.

FIG. 9(c) is a sectional view of the hinge mechanism 3 in the state of FIGS. 9(a) and 9(b). The lift shaft 37 pushes the second slider 52 against the spring 53, and the action length of the spring 53 becomes a length x2, which is shorter than the above-mentioned length x1. In the state shown in FIG. 9(c), the opening/closing angle of the opening/closing member 32 remains at the angle An1a, and as shown in FIG. 6, the torque T generated in the hinge mechanism 3 is near the maximum. That is, the first slider 51 is in a substantially maximum compressed state due to the engagement with the cam pin 31A, and an additional biasing force acts on the lift shaft 37 by an amount corresponding to the further compression of the spring 53. Therefore, when the first rotating member 33 is rotated in the direction in which the ADF 20 closes with respect to the opening/closing member 32, the distance of the spring 53 is shortened via the lift shaft 37, and the distance between the spring 53 and the opening/closing member 33 is reduced. Increase the torque in the opposite direction (opening direction).

However, since the lift shaft 37 is held by two members, the first rotating member 33 and the second rotating member 34, the urging force of the spring 53 can be distributed and received by these two members. Concentration of load can be avoided. Thereby, the thickness of the first rotating member 33 and the second rotating member 34 can be reduced, and the hinge mechanism 3 can be made smaller overall.

[Receiving pressure of the biasing force of the first biasing section by the lift shaft]
As explained above, the hinge mechanism 3 according to the present embodiment includes three shafts that serve as three pivot points and four members that pivot about these pivots. Furthermore, it has a first biasing part F1 that biases the ADF 20 in the opening direction. For example, in order to receive the biasing force of the spring 53 of the first biasing part F1 at one end and the other end, two shafts are required. is necessary. However, in the hinge mechanism 3 according to the present embodiment, the lift shaft 37 has the function of rotating the first rotation member 33 and the second rotation member 34 and the function of receiving the urging force of the spring 53. . Thereby, the number of axes of the hinge mechanism 3 can be reduced, and costs can be reduced.

Furthermore, since the lift shaft 37 is a shaft supported by both the first rotating member 33 and the second rotating member 34, even if the urging force of the spring 53 becomes large, especially during book equalization, The load can be distributed to the first rotating member 33 and the second rotating member 34. Therefore, the thicknesses of the first rotating member 33 and the second rotating member 34 can be made thinner, and thus costs can also be reduced.

[Possibility of other embodiments]
In addition, in the present embodiment described above, by forming the end surface 51a on the first slider 51 of the first biasing portion F1 to engage with the cam pin 31A, the torque in the opening direction is applied according to the opening/closing angle of the ADF 20. We have explained what changes T. However, the present invention is not limited to this, and it is also possible to simply receive the biasing force on one end side of the spring 53 and apply a constant torque in the direction to open the ADF 20. In this case, the spring 53 may be provided so as to directly contact the fixing member 31 and the lift shaft 37 without providing the first slider 51 and the second slider 52. In addition, as a mechanism for changing the torque T according to the opening/closing angle, for example, a cam mechanism that changes the urging force of the first urging part according to the opening/closing angle, such as interposing a cam that rotates according to the opening/closing angle, may be used. It doesn't matter what kind of mechanism it is.

Furthermore, in the present embodiment, the second biasing portion F2 is provided to bias the second rotating member 34 against the first rotating member 33 during equalization. However, the present invention is not limited to this, and equalization may be performed using the second rotating member 34 or the weight of the ADF 20 without providing the second biasing portion F2. Furthermore, the second biasing part F2 is not provided, and an adjustment screw that adjusts and fixes the abutting parts 21a and 22b in a balanced abutting state, like the horizontal position adjusting means 44 of Japanese Patent No. 5640303, is used. This may be used in place of the second biasing portion F2. Furthermore, even if the second biasing portion F2 is provided, it is not limited to the structure of this embodiment, but may be any structure that can bias the second rotating member 34 with respect to the first rotating member 33 during equalization. Any structure is acceptable.

Further, in the present embodiment, the elongated hole 34a is formed in the second rotation member 34, and the book rotation shaft 36 contacts the end portion 34aa to transfer the operating force of the user in the direction of closing the ADF 20 to the lift shaft 37. explained what is to be communicated. However, the present invention is not limited to this, and it is only necessary that the second rotating member 34 is provided with an abutted portion, and the first rotating member 33 is provided with an abutting portion that abuts the abutted portion, that is, the force is applied by the book rotating shaft 36. A structure that does not transmit data may also be used.

[Summary of this embodiment]
[Configuration 1]
an image reading unit including a light-transmitting member that transmits light; and a reading section that reads an image of a document through the light-transmitting member;
a document transport unit that transports the document so as to pass over the surface of the light-transmitting member;
a hinge mechanism that supports the document transport unit in an openable and closable manner with respect to the image reading unit;
The document transport unit is
a first contact portion that contacts the image reading unit;
a second abutting part that is disposed closer to the hinge mechanism than the first abutting part in a width direction perpendicular to the document conveyance direction and abuts the image reading unit;
The hinge mechanism is
a first member fixed to the image reading unit;
a first shaft supported by the first member;
a second member that rotates relative to the first member about the first axis;
a second axis arranged parallel to the first axis at a different position and supported by the second member;
a third member that rotates relative to the second member about the second axis;
a third axis arranged parallel to the second axis at a different position and supported by the third member;
A third member that rotates relative to the third member about the third axis such that the document conveyance unit is fixed and the first contact portion and the second contact portion contact the image reading unit. 4 parts and
a first biasing section having a first spring that applies a torque in a direction to open the document conveyance unit according to a rotation angle of the document conveyance unit with respect to the image reading unit;
The first member has a pressure receiving member that receives the biasing force of the first spring toward one side,
the third shaft receives a biasing force of the first spring toward the other side;
A document reading device characterized by:
[Configuration 2]
The first biasing section is
a first support member that abuts the pressure receiving member, supports the one end of the first spring, and is slidably supported by the second member;
a second support member that abuts the third shaft and supports the other end of the first spring;
When the rotation angle of the second member relative to the first member is changed, the distance between the pressure receiving member and the third axis is changed, and the biasing force of the first spring is changed. applying a torque in a direction to open the document conveyance unit according to a rotation angle of the document conveyance unit with respect to the image reading unit;
The document reading device according to configuration 1, characterized in that:
[Configuration 3]
When the third member is rotated with respect to the second member in a direction in which the document conveyance unit is closed with respect to the image reading unit, the first spring is compressed by the third shaft.
The document reading device according to configuration 1 or 2, characterized in that:
[Configuration 4]
When the document conveyance unit is closed with respect to the image reading unit and the second contact portion is in contact with the image reading unit, the image reading unit is in a closed state when viewed from the axial direction of the third axis. A first virtual line is an imaginary line connecting the tip of the second abutting portion that contacts the center of the third axis, and an imaginary line connecting the tip of the second abutting portion and the center of the second axis. When is the second virtual line,
The third axis is such that a smaller angle between the surface of the transparent member and the first imaginary line is smaller than a smaller angle between the surface of the transparent member and the second imaginary line. It is arranged as follows.
The document reading device according to any one of configurations 1 to 3, characterized in that:
[Configuration 5]
The third axis is in the closed state, is closer to the surface of the transparent member than the second axis when viewed from the axial direction, and is between the first axis and the second axis. located in
The document reading device according to configuration 4, characterized in that:
[Configuration 6]
A third virtual line is defined as a virtual line connecting the tip of the second contact portion that contacts the image reading unit and the center of the first shaft when viewed from the axial direction in the closed state; ,
The third axis is disposed on a side where the third virtual line passes through than the second axis,
The document reading device according to configuration 4 or configuration 5, characterized in that:
[Configuration 7]
When in the closed state, when viewed from the axial direction, a virtual line connecting the center of the first axis and the center of the third axis is a fourth virtual line,
The third axis is located above the third imaginary line and such that the angle between the first imaginary line and the fourth imaginary line is 90 degrees or more.
The document reading device according to configuration 6, characterized in that:
[Configuration 8]
The hinge mechanism includes a second biasing portion that applies a torque to the fourth member in a direction in which the contact portion is parallel to the surface of the light-transmitting member.
8. The document reading device according to any one of configurations 1 to 7, characterized in that:
[Configuration 9]
The third member has a first pressure receiving part that is disposed on the opposite side of the third shaft from the contact part and receives the urging force of the second urging part,
The fourth member has a second pressure receiving part that is disposed on the opposite side of the third axis from the contact part and receives the biasing force of the second biasing part,
The second biasing portion biases the first pressure receiving portion and the second pressure receiving portion in a direction toward each other.
The document reading device according to configuration 8, characterized in that:
[Configuration 10]
The third member includes a first plate portion disposed on a plane perpendicular to the third axis and engaged with the third axis, and a first plate portion disposed on a plane perpendicular to the first plate portion. a plate-shaped second plate portion,
The fourth member includes a plate-shaped third plate portion disposed on a plane perpendicular to the third axis and engaged with the third axis, and a third plate portion disposed on a plane perpendicular to the third plate portion. a fourth plate portion having a plate shape;
The first pressure receiving part is arranged on the second plate part,
The second pressure receiving part is arranged on the fourth plate part,
The second biasing section includes a second spring, a support member including a one-end support section that supports one end of the second spring, and a shaft section that extends through the second spring,
The fourth plate part is formed to pass through an other end support part that supports the other end of the second spring as the second pressure receiving part, and the other end support part, and the shaft part is disposed therethrough. having a hole;
The third plate part has a fixing part to which the shaft part is fixed as the first pressure receiving part.
The document reading device according to configuration 9, characterized in that:
[Configuration 11]
The fourth member has a long hole through which the second shaft is disposed and is elongated in the circumferential direction with the third shaft as the center;
The elongated hole allows relative movement between the third shaft and the fourth member when the fourth member rotates with respect to the third member.
11. The document reading device according to any one of Configurations 1 to 10, characterized in that:
[Configuration 12]
The document reading device according to any one of Configurations 1 to 11;
an image forming unit that forms an image read by the document reading device on a sheet;
An image forming apparatus characterized by:

3...Hinge mechanism/10...Document reading device/20...ADF (document transport unit)/21a...Abutment part (first abutment part)/21b...Abutment part (second abutment part)/22...Pressure plate ( Contact part) / 30... Reading part / 31... Fixed member (first member) / 31A... Cam pin (pressure receiving member) / 32... Opening/closing member (second member) / 33... First rotating member (third member) /33c...Top plate (second plate part)/33ca...Fixing hole (fixed part)/33d...Side plate (first plate part)/33p...Pressure receiving part (first pressure receiving part)/34...Second rotating member ( 4th member) /34a...Long hole/34c...Top plate (4th plate part)/34ca...Through hole (hole part)/34d...Side plate (3rd plate part)/34p...Pressure receiving part (2nd pressure receiving part, Other end support part) / 35... Hinge rotation axis (first axis) / 36... Book rotation axis (second axis) / 37... Lift axis (third axis) / 38... Stepped screw (support member) / 38a...head (one end support part)/38c...shaft part/39...second spring/40...image reading unit/51...first slider (first support member)/52...second slider (second support member) /53...Spring (first spring)/60...Image forming engine (image forming section)/100...Printer (image forming device)/201...Platen glass (light-transmitting member)/203...Original table glass (light-transmitting member) /An1...Opening/closing angle (rotation angle)/F1...First biasing part/F2...Second biasing part/L3...Virtual line (first virtual line)/L4...Virtual line (second virtual line)/L2 ...Virtual line (third virtual line)/L1...Virtual line (fourth virtual line)/T...Torque

Claims (12)

an image reading unit including a light-transmitting member that transmits light; and a reading section that reads an image of a document through the light-transmitting member;
a document transport unit that transports the document so as to pass over the surface of the light-transmitting member;
a hinge mechanism that supports the document transport unit in an openable and closable manner with respect to the image reading unit;
The document transport unit is
a first contact portion that contacts the image reading unit;
a second abutting part that is disposed closer to the hinge mechanism than the first abutting part in a width direction perpendicular to the document conveyance direction and abuts the image reading unit;
The hinge mechanism is
a first member fixed to the image reading unit;
a first shaft supported by the first member;
a second member that rotates relative to the first member about the first axis;
a second axis arranged parallel to the first axis at a different position and supported by the second member;
a third member that rotates relative to the second member about the second axis;
a third axis arranged parallel to the second axis at a different position and supported by the third member;
A third member that rotates relative to the third member about the third axis such that the document conveyance unit is fixed and the first contact portion and the second contact portion contact the image reading unit. 4 parts and
a first biasing section having a first spring that applies a torque in a direction to open the document conveyance unit according to a rotation angle of the document conveyance unit with respect to the image reading unit;
The first member has a pressure receiving member that receives the biasing force of the first spring toward one side,
the third shaft receives a biasing force of the first spring toward the other side;
A document reading device characterized by: The first biasing section is
a first support member that abuts the pressure receiving member, supports the one end of the first spring, and is slidably supported by the second member;
a second support member that abuts the third shaft and supports the other end of the first spring;
When the rotation angle of the second member relative to the first member is changed, the distance between the pressure receiving member and the third axis is changed, and the biasing force of the first spring is changed. applying a torque in a direction to open the document conveyance unit according to a rotation angle of the document conveyance unit with respect to the image reading unit;
The document reading device according to claim 1, characterized in that: When the third member is rotated with respect to the second member in a direction in which the document conveyance unit is closed with respect to the image reading unit, the first spring is compressed by the third shaft.
The document reading device according to claim 1, characterized in that: When the document conveyance unit is closed with respect to the image reading unit and the second contact portion is in contact with the image reading unit, the image reading unit is in a closed state when viewed from the axial direction of the third axis. A first virtual line is an imaginary line connecting the tip of the second abutting portion that contacts the center of the third axis, and an imaginary line connecting the tip of the second abutting portion and the center of the second axis. When is the second virtual line,
The third axis is such that a smaller angle between the surface of the transparent member and the first imaginary line is smaller than a smaller angle between the surface of the transparent member and the second imaginary line. It is arranged as follows.
The document reading device according to claim 1, characterized in that: The third axis is in the closed state, is closer to the surface of the transparent member than the second axis when viewed from the axial direction, and is between the first axis and the second axis. located in
The document reading device according to claim 4, characterized in that: A third virtual line is defined as a virtual line connecting the tip of the second contact portion that contacts the image reading unit and the center of the first shaft when viewed from the axial direction in the closed state; ,
The third axis is disposed on a side where the third virtual line passes through than the second axis,
The document reading device according to claim 4, characterized in that: When in the closed state, when viewed from the axial direction, a virtual line connecting the center of the first axis and the center of the third axis is a fourth virtual line,
The third axis is located above the third imaginary line and such that the angle between the first imaginary line and the fourth imaginary line is 90 degrees or more.
The document reading device according to claim 6, characterized in that: The hinge mechanism includes a second biasing portion that applies a torque to the fourth member in a direction in which the contact portion is parallel to the surface of the light-transmitting member.
The document reading device according to claim 1, characterized in that: The third member has a first pressure receiving part that is disposed on the opposite side of the third shaft from the contact part and receives the urging force of the second urging part,
The fourth member has a second pressure receiving part that is disposed on the opposite side of the third axis from the contact part and receives the biasing force of the second biasing part,
The second biasing portion biases the first pressure receiving portion and the second pressure receiving portion in a direction toward each other.
The document reading device according to claim 8, characterized in that: The third member includes a first plate portion arranged on a plane perpendicular to the third axis and engaged with the third axis, and a first plate portion disposed on a plane perpendicular to the first plate portion. a plate-shaped second plate portion,
The fourth member includes a plate-shaped third plate portion disposed on a plane perpendicular to the third axis and engaged with the third axis, and a third plate portion disposed on a plane perpendicular to the third plate portion. a fourth plate portion having a plate shape;
The first pressure receiving part is arranged on the second plate part,
The second pressure receiving part is arranged on the fourth plate part,
The second biasing portion includes a second spring, a support member including a one end support portion that supports one end of the second spring, and a shaft portion that extends through the second spring,
The fourth plate part is formed to pass through an other end support part that supports the other end of the second spring as the second pressure receiving part, and the other end support part, and the shaft part is disposed therethrough. having a hole;
The third plate part has a fixing part to which the shaft part is fixed as the first pressure receiving part.
The document reading device according to claim 9, characterized in that: The fourth member has a long hole through which the second shaft is disposed and is elongated in the circumferential direction with the third shaft as the center;
The elongated hole allows relative movement between the third shaft and the fourth member when the fourth member rotates with respect to the third member.
The document reading device according to claim 1, characterized in that: A document reading device according to any one of claims 1 to 11;
an image forming unit that forms an image read by the document reading device on a sheet;
An image forming apparatus characterized by:

Images