JP2008180892A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve workability, in an image forming apparatus, in assembling and so on, by preventing a document table cover from falling down when a scan unit is opened. <P>SOLUTION: The scan unit 3 of the image forming apparatus is journaled on the top of a printer housing 10 so as to be rotatable. On the top of the scan unit 3, the document table cover 11 is disposed so as to be rotatable. A part 13 that can be engaged is formed on the document table cover 11, and a locking mechanism 40 is disposed below the part 13. The locking mechanism 40 has: a connection rod 42 journaled by the printer housing 10 so as to be freely rotated; and a hook member 43 journaled by the scanner housing 35 so as to be rotatable, and connected to the connection rod 42. As the scan unit 3 rotates, the hook member 43 is rotated, an engaging hook 43c formed on the hooking member 43 projects beyond the upper face of the scan unit 3 and engages with the part 13 to be engaged. Consequently, the document table cover 11 is held in a closed state. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that forms an image on a recording sheet, and more particularly to an apparatus that includes a scan unit that reads a document placed on a document table as image data.

  2. Description of the Related Art Conventionally, a so-called flatbed scan unit that reads a document placed on a document table as image data by a sensor such as a CIS (Contact Image Sensor) is disposed below the scan unit and is imaged on a recording sheet. There is known a printer housing in which an image forming unit for forming the image forming unit is housed and rotatably supported. FIG. 6 shows an example of such an image forming apparatus. The image forming apparatus 81 includes a printer housing 810 in which an image forming unit 82 is housed, and a scan unit 83 that is pivotally supported at a portion near the upper back of the printer housing 810. A document table (not shown) is disposed on the upper surface of the scan unit 83, and a document table cover 811 is rotated on the upper back of the scan unit 83 with respect to the scan unit 83 so as to cover the upper surface of the document table. It is provided to be movable. The document table cover 811 is disposed so as to cover the upper surface of the document table by its own weight, and the user can place the document on the document table by lifting and rotating the document table cover 811. An opening 810a covered with the scan unit is formed in the upper portion of the printer casing 810. As shown by an arrow V in the figure, the scan unit 83 is rotated upward with respect to the printer casing 810, and the opening It is configured such that maintenance work or the like of the image forming unit 82 can be performed by opening the 810a to the outside.

  By the way, in the conventional image forming apparatus 81 as described above, when the rotation angle of the scan unit 83 with respect to the printer housing 810 increases, the document table cover 811 falls backward as indicated by an arrow W in the drawing. . During maintenance of the image forming apparatus 81, for example, if the document table cover 811 falls backward each time the scan unit 83 is opened, it is troublesome to return the document table cover 811 to the original closed state. Further, when the document table cover 811 is vigorously tilted backward, the document table cover 811 and the hinge member that pivotally supports the document table cover 811 may be damaged.

  With regard to such a problem, for example, Patent Document 1 discloses that when the scan unit is opened and closed, the hook is manually rotated to lock the document table cover to the scan unit, and the scan unit is attached only when the document table cover is closed. An image forming apparatus that can be opened is shown. However, in such an image forming apparatus, there is a problem that the user needs to manually operate the hook in order to lock the document table cover, which is cumbersome and troublesome. On the other hand, for example, by providing a support rod embedded in the scan unit and the printer housing so that both end portions are not detached from each other, the rotation angle of the scan unit is regulated, and the image forming apparatus is normally used. There is known an image forming apparatus in which a document table cover is prevented from falling even when a scan unit is opened. However, the support rod as described above cannot be used when the operation or the like needs to be performed by rotating the scan unit greatly, such as during manufacture of the image forming apparatus. Therefore, at the time of such work, it is necessary to perform assembly work or the like while paying attention to prevent the document table cover from falling backward, and there is a problem that workability is poor.

In Patent Document 2, the document cover is prevented from rotating from a predetermined angle by a stopper provided at the rear end of the housing, and the apparatus does not fall over even when the scan unit is rotated. An image forming apparatus is shown. However, in this configuration, since the document cover does not rotate more than a predetermined angle, the scan unit cannot be largely rotated when the document cover is attached. Patent Document 3 discloses an image forming apparatus configured such that a scanner unit and a document table cover are connected by a wire so that the document table cover does not open greatly even when the scanner unit is opened. ing. However, in this image forming apparatus, since the wires are connected, there is a problem that it is difficult to remove the document table cover when reading a document having a large thickness such as a book. In Patent Document 4, the image forming unit is moved back and forth in conjunction with the opening / closing operation of the document table cover so that the apparatus main body does not fall over even when the document table cover is largely opened. Although an image forming apparatus is shown, Patent Document 4 does not show an effective solution to the above problem.
Japanese Patent No. 3644376 Japanese Patent No. 3460993 Japanese Patent Laid-Open No. 2001-281717 JP 2004-93902 A

  The present invention has been made in view of the above problems, and image forming that can improve workability during assembling work without the document table cover falling down when the scan unit is opened. An object is to provide an apparatus.

  In order to achieve the above object, an invention according to claim 1 includes a printer housing having an opening formed at an upper portion thereof, a scanner housing disposed so as to cover the opening above the printer housing, A scan unit having a substantially rectangular document table disposed at an upper portion of a scanner housing; and a reading unit that is housed in the scanner housing and reads a document placed on the document table as image data; When the document placed on the document table is sandwiched between the document table and the scanner table, the document document is placed on the scanner case so as to be rotatable and covers the upper surface of the document table. A document table cover for bringing the document into close contact with the document table, and a document case housed in the printer housing, based on image data of the document read by the scan unit or image data input from an external device. An image forming unit having a function of forming an image on recording paper, the scanner housing is pivotally supported in the vicinity of the back of the printer housing so as to be substantially horizontally rotatable, and the scan unit is connected to the printer housing. In the image forming apparatus configured to be able to open and close the opening by rotating upward with respect to the body, a portion near the side of the lower surface of the document table cover is engaged downwardly. A lock hole penetrating into the scanner housing is formed in a portion corresponding to the engaged portion of the upper surface of the scanner housing. A lock mechanism that is displaced in accordance with the opening / closing posture of the scan unit with respect to the printer housing is disposed below, and the lock mechanism is disposed on the upper portion of the printer housing so as to be slidable in the front-rear direction. A slide member, a connecting rod that is pivotally supported at one end by a rod shaft support portion of the slide member so as to be rotatable with respect to the slide member, and a hook shaft support portion on an upper inner surface of the scanner housing. It is pivotally supported so as to be pivotable substantially horizontally, one end of which is pivotally connected to the other end of the connecting rod, and the other end is formed with an engagement hook that can be engaged with the engaged portion. A substantially rod-shaped hook member, and when the scan unit is in a closed state covering the opening, the hook member is in a substantially horizontal posture and the scan unit is rotated upward from the closed state. When the distance between the rod shaft support portion and the hook shaft support portion is changed, the other end portion of the hook member is pulled by the connecting rod, so that the hook member rotates around the hook shaft support portion. Move and engage The hook is configured to protrude upward from the lock hole, and when the document table cover is in a closed state, the engagement hook is moved from the lock hole as the scan unit is opened. The document table cover is rotated even when the rotation angle of the scan unit with respect to the printer housing is increased because the document table cover is held in a closed state. Therefore, the image forming apparatus can be easily assembled.

  According to a second aspect of the present invention, there is provided a printer housing having an opening formed in an upper portion thereof, and a scanner housing which is pivotally supported by the printer housing so as to cover the opening when closed. And a substantially rectangular document table disposed at an upper portion of the scanner casing, and a reading unit that is stored in the scanner casing and reads the document placed on the document table as image data. A scanning unit and an upper part of the scanner housing, which is disposed so as to be rotatable with respect to the scanner housing, and which is placed on the document table in a closed state covering the upper surface of the document table, A document table cover that holds the document in close contact with the document table by being sandwiched between the document table and the image data of the document read by the scan unit or input from an external device. The In the image forming apparatus including an image forming unit having a function of forming an image on recording paper based on the image data, an engaged portion is formed on the lower surface of the document table cover, and the scanner housing A lock hole penetrating into the scanner housing is formed in a portion corresponding to the engaged portion in the upper surface of the scanner. Below the lock hole portion, the printer housing of the scan unit is formed. A lock mechanism configured to project an engagement hook engageable with the engaged portion upward from the lock hole portion in conjunction with opening and closing of the body is provided, and the document table cover is closed. In this state, as the scan unit is rotated with respect to the printer housing, the engagement hook projects from the lock hole and engages with the engaged portion, and the document table cover closes. Keep state Those that are configured to be.

  According to a third aspect of the present invention, in the second aspect of the present invention, the lock mechanism includes a connecting rod whose one end is pivotally supported by a rod shaft support portion of the printer housing, and an inner portion of the scanner housing. A substantially rod-shaped hook member pivotally supported by a hook shaft support portion, one end portion of which is rotatably connected to the other end portion of the connecting rod, and the other end portion of which the engagement hook is formed; And when the scan unit is in a closed state covering the opening, the hook member is in a substantially horizontal posture, and when the scan unit is rotated upward from the closed state, the rod shaft support portion And the other end portion of the hook member is pulled by the connecting rod, so that the hook member rotates around the hook shaft support portion, and the engagement hook From the lock hole Those that are configured to protrude toward.

  According to the first aspect of the invention, when the document table cover is in the closed state, the engagement hook of the hook member protrudes and engages with the engaged portion as the scan unit is opened. Even if no special operation is performed to fix the cover in the closed state, the document table cover is held in the closed state. Therefore, even if the rotation angle of the scan unit with respect to the printer housing increases, the document table cover does not fall down, and the assembly operation of the image forming apparatus can be easily performed. Further, since the hook member of the lock mechanism is in a substantially horizontal posture when the scan unit is in the closed state and is housed inside the scanner housing, the image forming apparatus can be used during normal use when the scan unit is in the closed state. Is easy to use, and the appearance of the image forming apparatus is improved. Since the connecting rod of the lock mechanism is pivotally supported by a slide member arranged to be slidable in the front-rear direction, a wider range of scanning units can be obtained with the document table cover held closed by the lock mechanism. It can be rotated to an angle.

  According to the second aspect of the present invention, when the document table cover is in the closed state and the scan unit is rotated with respect to the printer housing, the engagement hook of the lock mechanism protrudes in conjunction with the rotation of the scan unit. Since the engaging portion engages with the engaged portion, the original table cover is held in the closed state without any special operation for fixing the original plate cover in the closed state. Accordingly, as described above, the document table cover does not fall down, and the image forming apparatus can be easily assembled.

  According to the invention of claim 3, since the hook member of the lock mechanism is in such a posture that the engagement hook does not protrude upward from the lock hole when the scan unit is in the closed state, the scan unit is in the closed state. During normal use, the image forming apparatus is easy to use, and the appearance of the image forming apparatus is improved.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 and 2 show an example of an image forming apparatus according to the present embodiment. The image forming apparatus 1 is of a so-called all-in-one type, and includes an image forming unit 2 housed in a resin printer housing 10 and a printer housing on the back side above the printer housing 10. A scanning unit 3 having a substantially rectangular parallelepiped shape, which is arranged in a state of being pivotally supported by a hinge 21 in the vicinity of the back portion of 10 so as to be horizontally rotatable, and reads an original (not shown) as image data, and an upper portion of the printer housing The operation button 4 that can be operated from the outside and the liquid crystal display unit 5 that displays the operation state of the image forming apparatus 1 and the like are arranged on the front surface of the printer housing 10, for example, such as a digital still camera or a memory card. It has a connector part 7 to which an external device is connected. A document table cover 11 is disposed on the scan unit 3. A paper feed tray 15 on which recording paper (not shown) to be conveyed to the image forming unit 2 is set is provided on the back of the printer casing 10. A paper discharge tray 16 is provided on which the recording paper on which the image 2 is formed is discharged. The image forming apparatus 1 includes, for example, image data input from an external device connected to the connector unit 7 or the like, or an external personal computer connected via a connector provided on the back of the printer housing 10, for example. And the like, and the image forming unit 2 has a function of forming an image on a recording sheet using image data read by the scan unit 3 or the like.

  The image forming unit 2 forms an image on recording paper by a so-called ink jet method. The image forming unit 2 includes, for example, a roller that feeds recording paper one by one from the paper feed tray 15 into the printer housing 10 and discharges it onto the paper discharge tray 16 and a motor that drives the rollers. A carriage 2a equipped with a paper transport mechanism (not shown), a head for ejecting ink onto the recording paper transported inside the printer housing 10, and the carriage 2a reciprocating in a direction substantially perpendicular to the recording paper transport direction. A motor to be driven, a driving belt (not shown), and the like are included. Note that the image forming unit 2 may form an image on a recording sheet by, for example, an electrophotographic method or a thermal transfer method.

  As shown in FIG. 2, an opening 10 a is formed above the printer housing 10, and the opening 10 a can be opened and closed by rotating the scan unit 3 with respect to the printer housing 10. It is configured to be able to. That is, when the image forming apparatus 1 is normally used, the opening 10a is closed by the scan unit 3 as shown in FIG. 1 so that the image forming unit 2 is not exposed to the outside. Then, as shown in FIG. 2, the scanning unit 3 is rotated upward with respect to the printer housing 10 so that the opening 10a is exposed to the outside. Maintenance work of the image forming unit 2 such as an operation of attaching an enclosed ink cartridge (not shown) or the like to the carriage 2a can be performed. The upper end of a substantially bar-shaped support arm 18 is connected to the lower surface of the scan unit 3. The support arm 18 is formed so that its lower end can be engaged with the upper surface of the printer housing 10. When the scan unit 3 is in the open state, the lower end portion of the support arm 18 is engaged with the upper surface of the printer housing 10 so that the support arm 18 is stretched between the scan unit 3 and the printer housing 10. The scan unit 3 can be held in an open state, and the maintenance work can be easily performed.

  The scan unit 3 is a box-shaped scanner housing 35 that is pivotally supported by the printer housing 10 and has a rectangular opening at the upper center thereof, and a document platen 3a made of, for example, glass disposed in the rectangular opening of the scanner housing 35. It is comprised by the substantially rectangular parallelepiped shape enclosed. Inside the scanner housing 35, below the document table 3a, for example, a reading unit 30 for reading a document as image data, which includes a motor 30a and a CIS (Contact Image Sensor) 30b driven by the motor 30a. Is stored. That is, the scan unit 3 moves the CIS 30b inside the scanner housing 35 while contacting the lower surface of the document table 3a, images the document placed on the document table 3a by the CIS 30b, and uses the document as image data. It is configured to read.

  The document table cover 11 is disposed above the scanner case 35 of the scan unit 3 so as to cover the document table 3 a exposed upward from the scanner case 35. The document table cover 11 is pivotally supported on the upper part of the slide hinge 20 that is slidably mounted in the vertical direction with respect to the scanner housing 35, and is rotatable with respect to the scanner housing 35 and can be displaced in the vertical direction. It is arranged. A sponge pad 12, for example, is attached to the lower surface of the document table cover 11 at a position corresponding to the document table 3 a in order to bring the document into close contact with the document table 3 a. The operation buttons 4 and the liquid crystal display unit 5 are disposed on a portion of the upper surface of the scan unit 3 that is not covered by the document table cover 11. When the document table cover 11 is in a closed state covering the upper surface of the document table 3a, the document placed on the document table 3a is sandwiched between the document table 3a and the document table 3a by its own weight. It is configured to be in close contact with the table 3a so that the original can be read satisfactorily. In this image forming apparatus 1, the document table cover 11 can be displaced up and down by the slide hinge 20, so that the document can be brought into close contact with the document table 3 a when reading a document having a large thickness such as a book. It is configured. The placement of the document on the document table 3a and the removal of the document from the document table 3a are performed in a state where the document table cover 11 is rotated with respect to the scan unit 3 to be opened and the document table 3a is exposed.

  Here, the image forming apparatus 1 is configured such that when the scan unit 3 is rotated with respect to the printer housing 10, the document table cover 11 is held in a closed state with respect to the scan unit 3. The document table cover 11 is opened and closed with respect to the printer housing 10 of the scan unit 3 at an engaged portion 13 projecting from the lower surface of the document table cover 11 near the side of the image forming apparatus 1 toward the lower surface. The lock mechanism 40 configured to be displaced according to the posture is engaged to be held in the closed state.

  3 and 4 show a portion where the engaged portion 13 and the lock mechanism 40 of the image forming apparatus 1 are arranged. In the present embodiment, a portion of the upper surface of the scanner housing 35 corresponding to the engaged portion 13 has a lock hole that penetrates the scanner housing 35 in a long hole shape such that the front-rear direction is the longitudinal direction. 36 is formed. In addition, in the lower surface of the scanner housing 35, a portion corresponding to the lock hole portion 36 is formed with an elongated hole-shaped through hole 37 whose longitudinal direction is the longitudinal direction, like the lock hole portion 36. A slide groove 10b is formed in a portion corresponding to the through hole 37 on the upper surface of the printer housing 10 so as to extend in the front-rear direction.

  As shown in FIG. 4, the engaged portion 13 includes a shaft-like portion 13 a that is substantially horizontal in the left-right direction of the image forming apparatus 1, and side plates 13 b that are connected to both sides thereof from the lower surface of the document table cover 11. It is formed so as to be supported so as to be separated downward. The engaged portion 13 is formed integrally with the document table cover 11 and is configured to reduce the manufacturing cost of the image forming apparatus 1.

  The lock mechanism 40 includes a slide member 41, a connecting rod 42 pivotally supported by the slide member 41, a hook member 43 having one end connected to the connecting rod 42, and the like. As shown in FIG. 3, the slide member 41 has a rod shaft support portion 41a having a clevis shape at the upper portion of the slide member 41, and is fitted in the slide groove 10b so as to be slidable in the front-rear direction. One end portion of the connecting rod 42 is pivotally supported by the rod shaft support portion 41 a so as to be rotatable with respect to the slide member 41 so that the rotation shaft is substantially horizontal, and the other end side is interposed through the through hole 37. Are disposed so as to be embedded in the scanner casing 35. The hook member 43 has, for example, a substantially rod shape, and a hook rotation shaft 43a is formed in the vicinity of the center portion thereof. A hook shaft support 38 projects downward from the upper inner surface of the scanner housing 35. The hook member 43 is rotatably disposed in a state where the hook rotation shaft 43a is pivotally supported on the hook shaft support portion 38 so that the rotation shaft is substantially horizontal. A connecting shaft 43b is formed at one end of the hook member 43, and is connected to the connecting rod 42 so as to be rotatable relative to each other so that the rotating shaft is substantially horizontal. At the other end of the hook member 43, an engagement hook 43c that can be engaged with the engaged portion 13 is formed. As shown in the figure, the hook member 43 is disposed so that the engagement hook 43 c is in a position corresponding to the lock hole portion 36.

  5A and 5B show the lock mechanism 40. FIG. The operation of the lock mechanism 40 will be described below with reference to FIGS. 5 (a) and 5 (b). As shown in FIG. 5A, when the scan unit 3 is in a closed state covering the opening 10a, the hook member 43 is configured to be in a substantially horizontal posture. That is, when the scan unit 3 is in the closed state, the hook member 43 including the engagement hook 43 c is configured not to protrude above the scanner housing 35. At this time, the document table cover 11 can be opened as indicated by a dotted line in the drawing, and a document can be placed on the document table 3a.

  As indicated by an arrow A in FIG. 5B, when the scan unit 3 is rotated upward from the closed state, the distance between the rod shaft support portion 41a and the hook shaft support portion 38 changes. Accordingly, as shown by an arrow R in the figure, the connecting rod 42 rotates around the rod shaft support portion 41a, and the end of the hook member 43 on the side of the connecting shaft 43b is pulled by the connecting rod 42, whereby the hook member 43 rotates around the hook rotation shaft 43a. That is, when the scan unit 3 is in the open state, the hook member 43 rotates with respect to the scanner housing 35, and the engagement hook 43c is located above the scanner housing 35 via the lock hole 36 as shown in FIG. Protrusively. In the present embodiment, the engagement hook 43c rotates by a predetermined angle (for example, an angle when the support arm 18 is stretched between the scan unit 3 and the printer housing 10) from the closed state of the scan unit 3. The engaging hook 43c protruding upward from the scanner housing 35 is positioned so as to engage with the engaged portion 13 of the document table cover 11 that is closed with respect to the scan unit 3. Has been. In the present embodiment, the slide unit 41 is slid backward as indicated by the arrow S in FIG. 5B from the state in which the engagement hook 43c is engaged with the engaged portion 13, whereby the scan unit 3 is configured to be able to rotate further upward from the predetermined angle. The angle of the scan unit 3 with respect to the printer housing 10 when the engagement hook 43c engages the engaged portion 13 is not limited to the above, and for example, the scan unit 3 is rotated from the closed state. Sometimes it may be configured to engage immediately.

  Thus, in the present embodiment, when the document table cover 11 is in the closed state, the engaging hook 43c protrudes and engages the engaged portion 13 as the scan unit 3 is opened. Even if no special operation is performed to fix the document table cover 11 in the closed state, the document table cover 11 is held in the closed state. Therefore, even if the rotation angle of the scan unit 3 with respect to the printer housing 10 is increased, the document table cover 11 does not fall backward, and the assembly operation of the image forming apparatus 1 can be performed easily. Further, since the hook member 43 is in a substantially horizontal posture when the scan unit 3 is in the closed state and is housed inside the scanner housing 35, image formation is performed during normal use when the scan unit 3 is in the closed state. The apparatus 1 is easy to use, and the appearance of the image forming apparatus 1 is good. Since the slide member 41 on which the connecting rod 42 is pivotally supported is disposed so as to be slidable in the front-rear direction, the scan unit 3 can be rotated at a wider angle even when the document table cover 11 is held closed. Can be moved.

  In addition, this invention is not limited to the structure of the said embodiment, A various deformation | transformation is possible suitably in the range which does not change the meaning of invention. For example, the lock mechanism does not have to be formed of a substantially rod-shaped member as described above. For example, a rocker arm that is pivotally supported by the scanner housing is adapted to the rotation of the scan unit. And may be configured to rotate. Further, the engaged portion may be formed so that the lock mechanism can be engaged with the document table cover. For example, the engaged portion is configured by a member different from the document table cover and attached to the document table cover. It may be anything.

1 is a perspective view illustrating an example of an image forming apparatus according to an embodiment of the present invention. The perspective view which shows the state which rotated the scanning unit of the said apparatus. The perspective view which shows the locking mechanism of the said apparatus. The perspective view which shows the said locking mechanism and to-be-engaged part. (A) is a side view showing the lock mechanism when the scan unit is in a closed state, and (b) is a side view showing the lock mechanism when the scan unit is in an open state. The side view which shows an example of the conventional image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Image forming part 3 Scan unit 3a Document base 10 Printer housing 10a Opening part 11 Document base cover 13 Engaged part 30 Reading part 35 Scanner housing 36 Lock hole part 38 Hook shaft support part 40 Lock mechanism 41 Slide Member 41a Rod shaft support portion 42 Connecting rod 43 Hook member 43a Hook rotation shaft 43c Engagement hook

Claims (3)

A printer housing having an opening at the top;
A scanner casing disposed above the printer casing so as to cover the opening; a substantially rectangular document table disposed at an upper portion of the scanner casing; and housed in the scanner casing. A scanning unit having a reading unit that reads a document placed on the document table as image data;
By placing the document placed on the document table between the scanner table and the document table, when the document document is placed in the upper part of the scanner casing and is in a closed state covering the upper surface of the document table, A document table cover for bringing the document into close contact with the document table;
An image forming unit housed in the printer casing and having a function of forming an image on a recording sheet based on image data of a document read by the scan unit or image data input from an external device;
The scanner housing is pivotally supported in the vicinity of the back of the printer housing so as to be rotatable substantially horizontally, and the opening can be opened and closed by rotating the scan unit upward with respect to the printer housing. In the configured image forming apparatus,
An engaged portion that protrudes downward is formed in the vicinity of the side portion of the lower surface of the document table cover,
Of the upper surface of the scanner housing, a portion corresponding to the engaged portion is formed with a lock hole that penetrates the scanner housing.
Below the lock hole, a lock mechanism that is displaced according to the opening / closing posture of the scan unit with respect to the printer housing is disposed,
The locking mechanism is
A slide member disposed on an upper portion of the printer housing so as to be slidable in the front-rear direction;
A connecting rod that has one end pivotally supported substantially horizontally by the rod shaft support portion of the slide member and is rotatably arranged with respect to the slide member;
It is pivotally supported by a hook shaft support portion on the upper inner surface of the scanner casing so as to be rotatable substantially horizontally, and one end portion thereof is rotatably connected to the other end portion of the connecting rod, and the other end portion is engaged. A hook member having a substantially rod shape in which an engagement hook that can be engaged with the portion is formed,
When the scan unit is in a closed state covering the opening, the hook member is in a substantially horizontal posture,
When the scan unit is rotated upward from the closed state, the distance between the rod shaft support portion and the hook shaft support portion is changed, and one end portion of the hook member is pulled by the connecting rod, The hook member is configured to rotate around the hook shaft support portion, and the engagement hook protrudes upward from the lock hole portion,
When the document table cover is in the closed state, as the scan unit is opened, the engagement hook protrudes from the lock hole and engages with the engaged portion, so that the document table cover is closed. Even if the rotation angle of the scan unit with respect to the printer housing is increased, the document table cover can be prevented from rotating and falling, and the image forming apparatus can be easily assembled. An image forming apparatus configured to be able to perform the following. A printer housing having an opening at the top;
A scanner housing pivotally supported by the printer housing and disposed so as to cover the opening when in the closed state; a substantially rectangular original platen disposed on an upper portion of the scanner housing; A scan unit having a reading unit housed in the scanner casing and reading a document placed on the document table as image data;
An upper part of the scanner housing is disposed so as to be rotatable with respect to the scanner housing, and the original placed on the original table when the upper surface of the original table is closed is connected to the original table. A document table cover that holds the document in close contact with the document table,
An image forming unit housed in the printer casing and having a function of forming an image on a recording sheet based on image data of a document read by the scan unit or image data input from an external device; In the image forming apparatus,
An engaged portion is formed on the lower surface of the document table cover,
Of the upper surface of the scanner housing, a portion corresponding to the engaged portion is formed with a lock hole that penetrates the scanner housing.
Below the lock hole portion, an engagement hook that can be engaged with the engaged portion is projected upward from the lock hole portion in conjunction with opening and closing of the scan unit with respect to the printer housing. A locking mechanism is provided,
When the document table cover is in a closed state, as the scan unit is rotated with respect to the printer housing, the engagement hook protrudes from the lock hole and engages the engaged portion. An image forming apparatus, wherein the document table cover is held in a closed state. The lock mechanism is pivotally supported at one end thereof by a connecting rod pivotally supported by a rod shaft support portion of the printer housing and a hook shaft support portion inside the scanner housing. A hook portion having a substantially rod shape or an arm shape, wherein the portion is rotatably connected to the other end portion of the connecting rod, and the engagement hook is formed at the other end portion;
When the scan unit is in a closed state covering the opening, the hook member is in a posture such that the engagement hook does not protrude upward from the lock hole,
When the scan unit is rotated upward from the closed state, the distance between the rod shaft support portion and the hook shaft support portion is changed, and one end portion of the hook member is pulled by the connecting rod, The image forming apparatus according to claim 2, wherein the hook member rotates around the hook shaft support portion, and the engagement hook protrudes upward from the lock hole portion.

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