JP5359358B2 - Image reading apparatus and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reader having a simple configuration, the image reader preventing an original document from falling when an original document cover is opened or closed without increasing the number of components; and to provide an image forming device having the image reader. <P>SOLUTION: A sensor 6 consisting of a light-emitting means 6a and a light-receiving means 6b is attached on an upper surface 1a1 of an intermediate position of a line connecting hinge means 3A and 3B of a device body 1a. Upper surfaces 6a1 and 6b1 of the light-emitting means 6a and the light-receiving means 6b of the sensor 6 protrude to be higher than a surface 2a of an original document placing glass platen 2. With this configuration, when an original document P adsorbed and raised by an original document-pressing member 5 falls by its own weight, an end P1 of the original document P abuts on the tip of the sensor 6 to prevent the original document P from entering a gap G between the hinge means 3A, 3B. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an image reading apparatus that reads an image of a document placed on a document placing glass table such as a copying machine, a facsimile machine, and a scanner by an imaging sensor, and an image forming apparatus including the image reading apparatus.

Normally, in an image reading apparatus 1 that reads an image of a document placed on a document placement glass table such as a copying machine, a facsimile machine, or a scanner by an imaging sensor, a document P is placed as shown in FIG. The document placing glass table 2 and the document cover 4 that is spaced apart from the vicinity of the rear side end of the document placing glass table 2 and opens or closes the surface 2a of the document placing glass table 2 are rotatable. Two supporting hinge means 3A, 3B are provided. Then, on the inner surface of the document cover 4, when reading the document P placed on the document placement glass table 2, the document P is placed from above so that the document P comes into close contact with the surface of the document placement glass table 2. A document pressing member 5 made of a sheet material having elasticity for pressing is attached.
In such an image reading apparatus 1, when reading the document P, the document placing glass table 2 is closed with the document cover 4 and the document P is pressed against the surface of the document placing glass table 2 by the document pressing member 5. After the original P is read, the original cover 4 is opened and the operator removes the original P read from the original placement glass table 2 by hand. At this time, when the document cover 4 is rotated to open the document placing glass table 2, the document P is attracted to the surface of the document pressing member 5 and is lifted from the document placing glass table 2, and thereafter, as shown in FIG. As indicated by the arrows, the document P may slip off from the surface of the document pressing member 5 on which the document P is inclined, and may fall from the gap G between the hinge means 3A and 3B to the back of the image reading apparatus. is there.
In order to prevent such an accident, for example, as described in Patent Document 1, a gap G between two hinge means is inserted into the gap G between the upper surface of the image reading apparatus main body in conjunction with opening and closing of the document cover. It has been proposed to arrange the protruding and protruding projections as a document fall prevention member. Japanese Patent Application Laid-Open No. 2004-228561 proposes providing an obstacle member that covers at least a part of a gap formed between the rear side end portion of the document placing glass table and the document cover that opens the document placing glass table. Has been.

However, in the device described in Patent Document 1, it is necessary to provide a protrusion that protrudes and protrudes from the upper surface of the main body of the image reading apparatus in conjunction with opening and closing of the document cover, and in the device described in Patent Document 2, an obstruction member that covers at least a part of the gap needs to be provided. For this reason, there are problems that the number of parts increases, costs increase, and the configuration becomes complicated.
The present invention has been made in view of the above circumstances, and without increasing the number of parts, an image reading apparatus capable of preventing document dropping when the document cover is opened and closed with a simple configuration, and an image forming apparatus provided with the image reading apparatus The purpose is to provide.

In order to solve the above problems, the invention described in claim 1 is directed to a document placing glass table on which a document is placed, a document cover for closing an upper surface of the document placing glass table, and the document placing glass. A plurality of hinge means spaced apart from one side end of the table and rotatably supporting the document cover; and arranged to face the document placement glass table of the document cover; A document pressing member that presses a document placed on the upper surface of the document placing glass table when the cover is closed against the upper surface of the document placing glass table ; a light emitting unit; and a light receiving unit; A sensor for detecting the opening / closing of the document, a region of the document cover facing the sensor, a recess for housing the sensor when the document cover is closed, and the document cover being closed in the recess In front of the light emitting means A light-shielding portion that shields light from the light-receiving means, and the sensor protrudes higher than a lower end edge of the document cover when the document cover is opened to the maximum, and between the plurality of hinge means In addition, the image reading unit is arranged so that the distance between the sensor and the adjacent hinge means is smaller than the short size of a standard document of a minimum size that can be read by placing it on the glass platen. Device.

According to a second aspect of the present invention, there is provided an image forming apparatus comprising the image reading apparatus according to the first aspect.

According to the present invention, it is possible to provide an image reading apparatus and an image forming apparatus including the image reading apparatus that can prevent document dropping when the document cover is opened and closed with a simple configuration without increasing the number of parts .

FIG. 3 is a perspective view showing a state in which a document cover of the image reading apparatus according to the first embodiment of the present invention is opened. It is the front view seen from the arrow A direction of FIG. It is a side view at the time of seeing from the arrow CB direction of FIG. FIG. 3 is a cross-sectional view taken along the line AA in FIG. 2 when the document cover is closed. It is a perspective view which shows the optical unit in the image reading apparatus main body shown in FIG. It is a schematic diagram for demonstrating the effect | action of the optical unit shown in FIG. It is a front view for demonstrating the arrangement position and upper surface height of the sensor of the image reading apparatus which concerns on 1st Embodiment by this invention. It is a perspective view which shows the state which open | released the document cover of the image reading apparatus which concerns on 2nd Embodiment by this invention. 1 is a schematic diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. It is a perspective view which shows the state which opened the document cover of the conventional image reading apparatus. FIG. 10 is a side view showing a document dropping state of a conventional image reading apparatus.

The present inventor examined measures against an accident in which the document P slips off from the surface of the document pressing member 5 on which the document P is inclined and falls behind the image reading device from the gap G between the hinge means 3A and 3B. When performing the above, it was examined whether or not the document could be prevented from falling by using the structural members conventionally used in the image reading apparatus.
In the conventional image reading apparatus, as shown in FIG. 10 described above, a sensor 6 for detecting the opening / closing of the document cover 4 is disposed between the hinge means 3A and 3B. Thought. As shown in FIG. 10, the conventional sensor 6 includes a light emitting means 6a and a light receiving means 6b. The light emitting means 6a and the light receiving means 6b are connected to the hinge means 3A, 3B on the upper surface 1a1 of the image reading apparatus main body 1a. Between the two. The detection protrusion 6c detected by the sensor 6 protrudes from the inner surface 4a of the document cover 4, and when the document cover 4 is rotated to close the surface of the document placement glass table 2, The detection protrusion 6c is inserted into the slit 6d between the light emitting means 6a and the light receiving means 6b to shield the light from the light emitting means 6a, so that the closed state of the document cover 4 can be detected.

In this case, the upper surfaces 6a1 and 6b1 of the light emitting means 6a and the light receiving means 6b are arranged so that the surface of the document pressing member 5 is in close contact with the surface of the document placing glass table 2 when the document cover 4 is closed. The position is set to be lower than the surface of the document placing glass table 2. For this reason, in this conventional sensor 6, as shown in FIG. 11, when the document P adsorbed to the opened document pressing member 5 falls by its own weight, the leading end P1 of the document P becomes the light emitting means 6a and the light receiving means 6b. It has been found that the original P passes through the upper surfaces 6a1 and 6b1 and enters the gap G, and the original P falls behind the apparatus main body 1a.
As a result of further investigation based on this investigation, as long as at least one of the upper surfaces 6a1 and 6b1 of the light emitting means 6a and the light receiving means 6b protrudes higher than the surface of the document placing glass table 2, the opened document pressing member When the document P adsorbed by 5 falls by its own weight, it is possible to prevent the leading end P1 of the document P from coming into contact with the leading end portions of the light emitting means 6a and the light receiving means 6b and entering the gap G. I found.

On the other hand, when at least one of the upper surfaces 6a1 and 6b1 of the light emitting means 6a and the light receiving means 6b is made to protrude higher than the surface of the document placing glass table 2 as described above, the projection is made when the document cover 4 is closed. The upper surfaces 6a1 and 6b1 thus brought into contact with the inner surface 4a of the document cover 4, making it difficult to properly bring the surface of the document pressing member 5 into close contact with the surface of the document placing glass table 2. For this reason, in the present invention, when the document cover 4 is closed, a recess for accommodating the upper surfaces 6a1 and 6b1 protruding from the inner surface 4a of the portion facing the sensor 6 is provided, and the surface of the document pressing member 5 is placed on the document placement. It was possible to make sure that the surface of the glass table 2 was properly adhered.
Further, since the widths of the upper surfaces 6a1 and 6b1 of the sensor 6 are small, the leading end P1 of the document P passes through the gap between the sensor 6 and the hinge means 3A or 3B depending on the arrangement position of the sensor 6, and the apparatus main body. The document P may fall behind 1a. Therefore, in the present invention, the distance between the sensor 6 and the hinge means 3A or 3B is smaller than the short dimension of the standard document of the minimum size that can be read by placing it on the document placing glass table. The arrangement of the hinge means 3A, 3B and the sensor 6 is selected to complete the present invention.

Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view showing a state in which a document cover of the image reading apparatus according to the first embodiment of the present invention is opened. FIG. 2 is a front view seen from the direction of arrow A in FIG. FIG. 3 is a side view when viewed from the direction of arrow CB in FIG. 4 is a cross-sectional view taken along the line AA in FIG. 2 when the document cover is closed. FIG. 5 is a perspective view showing an optical unit in the image reading apparatus main body shown in FIG. FIG. 6 is a schematic diagram for explaining the operation of the optical unit shown in FIG. FIG. 7 is a front view for explaining the sensor arrangement position and the top surface height of the image reading apparatus according to the first embodiment of the present invention.
As shown in FIG. 1, the image reading apparatus 1 according to the first embodiment includes an apparatus main body 1a including an optical unit for reading an original P, which will be described later, and an original placing glass table 2 attached to the apparatus main body 1a. And a document cover 4 for opening and closing. An automatic document feeder 8 (described later) is attached to the upper surface of the document cover 4, and a document pressing member 5 having a size capable of covering the entire document placement glass table 2 is disposed on the inner surface 4 a. Is attached at a position that covers the document placing glass table 2 when the is closed.

The document pressing member 5 forms an elastic plate state in which a sponge layer is covered with a plastic sheet such as a white polyester sheet or a resin flat plate. When the document cover 4 is closed, the document P is placed on the document. It is made to adhere elastically to the surface of the glass table 2. When the document cover 4 is opened, the document P may be attracted onto the document pressing member 5 and lifted upward as in the case of the above-described prior art.
On the other hand, on the upper surface 1a1 of the apparatus main body 1a, for example, a document placing glass table 2 on which an A3 size document P can be placed is attached. A reading glass table 9 for slit exposure for reading a document conveyed by an automatic document feeder 8 mounted on a document cover 4 (to be described later) is attached to the left side of the document placing glass table 2.
Further, in the vicinity of one side end portion on the back side of the document placing glass table 2, hinge means 3 A and 3 B for supporting the document cover 4 so as to be rotatable in the direction of the arrow B are separated from each other. The glass table 2 is juxtaposed in parallel with the side edge 2a. Furthermore, a sensor 6 comprising a light emitting means 6a and a light receiving means 6b is attached to the upper surface 1a1 at an intermediate position on the line connecting the hinge means 3A and 3B of the apparatus body 1a.

Then, the light emitting means 6a of the sensor 6 and the upper surfaces 6a1 and 6b1 of the light receiving means 6b protrude higher than the surface 2a of the document placing glass table 2 as shown in FIG. Therefore, as shown in FIG. 3, when the document P attracted and lifted on the document pressing member 5 falls by its own weight, the leading end P1 of the document P contacts the leading end of the sensor 6, and the hinge means 3A and It is possible to prevent entry into the gap G (see FIG. 2) with 3B.
Further, as shown in FIG. 1, the sensor 6 is disposed at an intermediate position on the line connecting the hinge means 3A and 3B. The adjacent hinge means 3A and 3B, the sensor 6, and the separation distance b are as follows. The distance is shorter than half the distance a between the hinge means. The separation distance b is the minimum size standard document P0 placed on the document placement glass table 2 (for example, when the maximum size standard document is A3 size, A5 size, maximum size standard document that can be placed). The distance is smaller than the short dimension D of A6 size). Accordingly, when the document P0 attracted and lifted on the document pressing member 5 falls by its own weight, the tip P01 of the document P0 always comes into contact with the tip of the sensor 6 and the gap G between the hinge means 3A and 3B. (See FIG. 2).

Further, as shown in FIG. 4, when the document cover 4 is closed, the portion of the document cover 4 facing the sensor 6 has a through hole 7 serving as a recess that can accommodate the upper surfaces 6 a 1 and 6 b 1 of the sensor 6. Is formed. Therefore, when the document cover 4 is closed, the upper surface 6a1 and 6b1 of the sensor 6 is not in contact with the inner surface 4a of the document cover 4, and the document placement glass table 2 is closed by the document cover 4, and the document pressing member 5 The document P can be properly brought into close contact with the surface of the document placing glass table 2.
In this embodiment, the through hole 7 is used as the recess that can accommodate the upper surfaces 6a1 and 6b1 of the sensor 6, but it may be a recessed hole with the upper surface closed instead of the through hole. However, when the through hole is used as a recess, there is an advantage that the heights of the upper surfaces 6a1 and 6b1 of the sensor 6 can be arbitrarily set. In FIG. 1 and FIG. 2, the member protruding into the through hole 7 is a detection protrusion 6 c for detecting opening and closing of the document cover 4. When the document cover 4 is closed, the detection protrusion 6c is inserted into the slit 6d between the light emitting means 6a and the light receiving means 6b and shields the light projected from the light emitting means. It is possible to detect that the document cover 4 is closed.
Further, in the image reading apparatus according to the first embodiment, as shown in FIG. 7, the heights of the upper surfaces 6a1 and 6b1 of the sensor 6 are determined from the position of the lower edge 4b of the document cover 4 when the document cover 4 is opened. By setting it high, it is possible to more reliably prevent the original P from entering the gap G, which is preferable.

Next, an optical unit that reads an image of the original P and converts it into an electric signal will be described with reference to FIGS.
In the image reading apparatus 1 according to the present embodiment, an optical unit 11 that reads an image of a document P and converts it into an electrical signal is built in the apparatus main body 1a. An image of the original P placed thereon is optically read to convert the image information into an electrical signal.
Specifically, as shown in FIG. 5 and FIG. 6, the optical unit 11 includes a first mirror unit 13 having a light source 12 and a first mirror 15 supported at both ends, and both ends below the document placing glass table 2. A second mirror unit 16 having a supported second mirror 17 and third mirror 18 is provided. Then, the reflected light of the light emitted from the light source 13 of the first mirror unit 13 to the image of the document P passes through the first mirror 15, the second mirror 17, and the third mirror 18 as indicated by a one-dot chain line in FIG. Then, the optical lens 19 forms a focused image on the image sensor 20, and the image sensor 20 converts the image into an electrical signal.

  Further, the first mirror unit 13 and the second mirror unit 16 are configured so that the first mirror unit 13 and the second mirror unit 16 are in response to an image reading request signal for each line sent from the host computer. As indicated by arrows C and D, the image is sequentially read while moving along the document P at a speed of 2: 1. In this case, the first mirror unit 13 moves forward at a constant speed, and the second mirror unit moves forward following the first mirror unit 13 at half the speed of the first mirror unit. As a result, the original P on the original placement glass table 2 is optically scanned. The original P on the original placement glass table 2 is irradiated by the light source 12, and the reflected light image is guided to the imaging lens 19 through the first mirror 15, the second mirror 17, and the third mirror 18, and this connection is performed. The image lens 19 forms an image on an image sensor 20 composed of a CCD (Charge Coupled Devices) or the like.

The image sensor 20 photoelectrically converts the reflected light image of the image of the original P into an analog image signal, and reads the image of the original P. Then, after the reading of the document is completed, the first mirror unit 13 and the second mirror unit 16 return to the leftmost home position position indicated by the solid line in FIG. The analog image signal output from the image sensor 20 is converted into a digital image signal by an analog / digital converter, and each image processing (binarization, multi-value conversion, Gradation processing, scaling processing, editing processing, and the like) are performed, and are sent to an image forming unit of an image forming apparatus described later to form an image.
In the image reading apparatus 1 according to the present embodiment having the above-described configuration, the upper surface of the sensor 6 that detects opening / closing of the document cover 4 is protruded higher than the document placing glass table 2, and between the hinge means 3A and 3B. In addition, the distance b between the hinge means 3A and 3B adjacent to the sensor 6 and the sensor 6 is smaller than the short dimension D of the standard document P0 of the minimum size that can be placed and read on the document placing glass table 2. When the document cover 4 is closed, the through-hole 7 that accommodates the upper surface of the sensor 6 is formed in the portion of the document cover 4 that faces the sensor 6, so that the number of parts can be easily increased. With this configuration, it is possible to provide an image reading apparatus that can prevent document dropping when the document cover is opened and closed.

Next, an image reading apparatus according to a second embodiment of the present invention will be described with reference to FIG. FIG. 8 is a perspective view showing a state in which the document cover of the image reading apparatus according to the second embodiment of the present invention is opened.
In the image reading apparatus according to the second embodiment, as shown in FIG. 8, in addition to the hinge means 3A and 3B, a plurality of hinge means for rotatably supporting the document cover 4 with respect to the apparatus body 1a. A hinge means 3C is disposed at an intermediate position between the hinge means 3A and 3B so that the document cover 4 can be supported more stably. The distance c between the hinge means 3A and the hinge means 3A and 3B adjacent to the hinge means 3C is smaller than the short dimension D of the minimum size original document P0 placed on the document placement glass table 2. . Therefore, when the document P0 attracted and lifted on the document pressing member 5 falls by its own weight, the leading end P01 of the document P0 always comes into contact with at least one of the hinge means 3A, 3B and 3C and the hinge means 3A and 3B. It is possible to prevent the gap G from entering the gap G (see FIG. 2).

Although an example using three hinge means has been described as the second embodiment, three or more, for example, four may be used. In this case, the distance between adjacent hinge means is the minimum size of the standard document P0 placed on the document placement glass table 2 (for example, when the maximum size of the standard document that can be placed is A3 size, A5 size, maximum It is sufficient to set the distance so that the distance is smaller than the short dimension D of A6 size when the loadable standard document is A4 size.
As described above, in this embodiment, the number of parts is increased by using the hinge means that rotatably supports the document cover 4 and arranging the hinge means at a predetermined interval. Therefore, it is possible to provide an image reading apparatus that can prevent document dropping when the document cover is opened and closed with a simple configuration.

Next, an image forming apparatus equipped with the image reading apparatus 1 according to the first embodiment will be described with reference to FIG. FIG. 9 is a schematic diagram showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention.
The image forming apparatus according to this embodiment includes an image reading apparatus that reads an image from a document on an image forming unit 60 that forms a toner image from a desired document image. As shown in FIG. 1, the image forming unit 60 corresponds to four colors of yellow (Y), magenta (M), cyan (C), and black (K) as an image carrier having a photosensitive layer on the surface. The drum-shaped photoconductors 61 corresponding to the number of minutes are provided. Further, around each photoconductor 61, a charging device 100 for charging each photoconductor 61 almost uniformly, and exposure for forming an electrostatic latent image by exposing the charged photoconductor 61 with laser light L. An apparatus 70, a developing device 63 that contains developer of four colors, yellow, magenta, cyan, and black, and forms a toner image corresponding to the electrostatic latent image on the photoreceptor 61; And a cleaning device 64 for removing residual toner. In FIG. 9, the charging device 100, the developing device 63, and the cleaning device 64 correspond to the number corresponding to four colors of yellow (Y), magenta (M), cyan (C), and black (K). Although the drum-shaped photoconductor 61 is basically the same configuration, these devices around the black photoconductor 61 are represented by reference numerals.

Further, the image forming apparatus includes a roller-shaped primary transfer device 62 that transfers a toner image on the photoreceptor 61, an endless belt-shaped intermediate transfer belt 50 to which the toner image on the photoreceptor 61 is transferred, and an intermediate transfer A secondary transfer device 51 that transfers the toner image of the belt 50 onto the recording paper, and a fixing device 80 that fixes the toner image on a recording medium such as a recording paper to which the toner image of the intermediate transfer belt 50 is transferred are provided.
The recording medium is conveyed from one of the paper feeding devices 26 and 27 that store the recording medium one by one to the registration roller 23 by the conveyance roller in the conveyance path 28, where it is synchronized with the toner image on the photoconductor 61. Is measured and conveyed to the transfer position.
As shown in FIG. 9, the exposure device 70 in the image forming apparatus irradiates the surface of the photoreceptor 61 uniformly charged by the charging device 100 with a light beam L corresponding to the document image, and has a photoconductive property. An electrostatic latent image is formed on the body 61. The light beam L may be a laser beam or the like by a lamp such as a fluorescent lamp or a halogen lamp, or a semiconductor element such as an LED or LD. Here, an LD element is used when irradiation is performed in synchronization with the rotation speed of the photosensitive member 61 by a signal from an image processing unit (not shown).
The developing device 63 includes a developing roller that is a developer carrying member, and the toner stored in the developing device 63 is conveyed to a stirring unit by a supply roller, and is mixed and stirred with a developer including a carrier. 61 is conveyed to the development area facing 61. At this time, the positively or negatively charged toner is transferred to the electrostatic latent image on the photoreceptor 61 and developed. The developer may be a magnetic or non-magnetic one-component developer or a combination thereof, or a wet developer.

The primary transfer device 62 transfers the toner image developed on the photoreceptor 61 to the intermediate transfer belt 50 by forming an electric field having a polarity opposite to the polarity of the toner from the back side of the intermediate transfer belt 50. The primary transfer device 62 may be any one of a corotron, a scorotron corona transfer device, a transfer roller, and a transfer brush. Thereafter, in synchronization with the recording medium conveyed from the paper feeding device 26 or 27, the toner image is transferred onto the recording medium by transfer by the secondary transfer device 51 again. Here, the first transfer may be performed directly on the recording medium instead of the intermediate transfer belt 50.
The fixing device 80 heats and / or pressurizes the toner image on the recording medium to fix and fix the toner image on the recording medium. Here, the toner is passed between the pair of pressure rollers 80b and the fixing roller 80a, and at this time, heat and pressure are applied to fix the toner while the toner binder resin is melted. The pressure roller 80b and the fixing roller 80a of the fixing device 80 may be in a belt shape instead of a roller shape, or may be fixed by heat irradiation with a halogen lamp or the like.
The cleaning device 64 for the photoconductor 61 cleans and removes the toner remaining on the photoconductor 61 without being transferred, and enables the next image formation. The cleaning device 64 may be any system such as a blade made of rubber such as urethane or a fur brush made of fiber such as polyester.

The operation of the image forming apparatus according to this embodiment will be described below. The image reading apparatus 1 sets a document on the document table 8 a of the automatic document feeder 8, or opens the automatic document feeder 8 (document cover) and sets a document on the document placement glass table 2. Then, the automatic document feeder 8 is closed to hold the document.
When a start switch (not shown) is pressed, when the original is set on the automatic document feeder 8, the original is conveyed one by one onto the slit exposure reading glass table 9 by the conveying roller 8b, and then the other The first mirror unit 13 and the second mirror unit 16 are made to travel immediately when a document is set on the document placement glass table 2. Then, the first mirror unit 13 emits light from the light source, and the reflected light from the document surface is further reflected toward the second mirror unit 16, reflected by the mirror of the second mirror unit 16, and passed through the imaging lens 19. It puts in the image sensor 20 and reads image information.
The read image information is sent to this control unit. Based on the image information received from the image reading device 1, the control unit controls an LD or LED (not shown) disposed in the exposure device 70 of the image forming unit 60 to write laser light toward the photoconductor 61. L is irradiated. By this irradiation, an electrostatic latent image is formed on the surface of the photoreceptor 61.

The paper feeding unit 25 feeds the recording medium from the multi-stage paper feeding cassette 26 by the paper feeding roller, separates the fed recording medium by the separation roller, and feeds it to the paper feeding path 28, so as to be fed to the paper feeding path of the image forming unit 60. The recording medium is conveyed by a conveyance roller. In addition to the paper feed unit 25, manual paper feed is also possible. A manual feed tray for manual feed and a separation roller for separating the recording medium on the manual tray one by one toward the manual feed path are also provided on the side of the apparatus. I have.
Each of the registration rollers 23 discharges only one recording medium placed on the paper feed cassette 26 and sends it to a secondary transfer unit positioned between the intermediate transfer belt 50 and the secondary transfer device 51. When the image forming unit 60 receives the image information from the reading unit 30, the latent image is formed on the photosensitive member 61 by performing the laser writing or developing process as described above.
The developer in the developing device 63 is drawn up and held by a magnetic pole (not shown) to form a magnetic brush on the developing roller 63a. Further, the toner is transferred to the photosensitive member 61 by the developing bias voltage applied to the developing roller 63a, and the electrostatic latent image on the photosensitive member 61 is visualized to form a toner image. As the developing bias voltage, an AC voltage and a DC voltage are superimposed. Next, one of the paper feed rollers of the paper feed unit 25 is operated to feed a recording medium having a size corresponding to the toner image.
Along with this, one of the support rollers 53, 54, and 55 is rotationally driven by the drive motor, the other two support rollers are driven to rotate, and the endless intermediate transfer belt 50 is rotated and conveyed. At the same time, the photoreceptor 61 is rotated by each image forming unit to form black, yellow, magenta, and cyan single-color images on the photoreceptor 61, respectively. Then, along with the conveyance of the intermediate transfer belt 50, these single color images are sequentially transferred to form a composite color toner image on the intermediate transfer belt 50.

On the other hand, one of the paper feed rollers of the paper feed unit 25 is selectively rotated, the recording medium is fed out from one of the paper feed cassettes 26, separated one by one by the separation roller, and put into the paper feed path 28, and then fed by the transport roller The recording medium is guided to the paper feed path in the image forming unit 60 of the image forming apparatus, and the recording medium is abutted against the registration roller 23 and stopped.
Then, the registration roller 23 is rotated in synchronization with the composite color toner image on the intermediate transfer belt 50, and the recording medium is sent to the secondary transfer portion which is a contact portion between the intermediate transfer belt 50 and the secondary transfer device 51. The toner image is secondarily transferred and recorded on the recording medium due to the influence of the secondary transfer bias and the contact pressure formed in the secondary transfer portion. Here, the secondary transfer bias is preferably a direct current.
The recording medium after the image transfer is sent to the fixing device 80 by the transport belt of the secondary transfer device, and the fixing device 80 fixes the toner image by applying pressure and heat by the pressure roller, and then the discharging roller 41. The paper is discharged onto the paper discharge tray 40. In the present embodiment, the image forming unit 60 constitutes a process cartridge.

In this image forming apparatus, since the image reading apparatus according to the first embodiment described above is mounted as the image reading apparatus 1, the automatic document feeder 8 has a simple configuration without increasing the number of parts. It is possible to provide an image forming apparatus that can prevent document dropping at the time of opening and closing. That is, even if the automatic document feeder 8 is opened / closed with respect to the document placing glass table 2, the upper surface of the sensor 6 (see FIG. 1) that detects the opening / closing of the automatic document feeder 8 remains on the document placing glass table 2. A through-hole 7 that protrudes higher and accommodates the upper surface of the sensor 6 is formed, and the adjacent hinge means 3A and 3B and the sensor 6 are separated from each other by a minimum distance b that is placed on the document placing glass table 2. The distance is smaller than the short dimension D of the standard document P0.
Accordingly, when the document P0 attracted and lifted on the document pressing member 5 falls by its own weight, the tip P01 of the document P0 always comes into contact with the tip of the sensor 6 and the gap G between the hinge means 3A and 3B. (See FIG. 2).

  DESCRIPTION OF SYMBOLS 1 Image reading apparatus, 1a apparatus main body, 1a1 upper surface, 2 document mounting glass stand, 2a surface, 2b side edge, 3A, 3B, 3C hinge means, 4 document cover, 4a inner surface, 4b lower end edge, 5 document pressing member , 6 sensor, 6a light emitting means, 6b light receiving means, 6a1, 6b1 upper surface, 6c detection protrusion, 7 through-hole, 8 automatic document feeder, 11 optical unit, 12 light source, 13 first mirror unit, 15 first Mirror, 16 Second mirror unit, 17 Second mirror, 18 Third mirror, 19 Imaging lens, 20 Imaging sensor, 50 Intermediate transfer belt, 51 Secondary transfer device, 60 Image forming unit, 61 Photoconductor, 62 Primary Transfer device, 63 developing device, 64 cleaning device, 70 exposure device, 80 fixing device, 100 charging device

Japanese Patent Laid-Open No. 10-20416 Japanese Patent No. 3650042

Claims (2)

A document placing glass table on which a document is placed;
A document cover for closing the upper surface of the document placing glass table;
Wherein disposed spaced apart at one end of the original placing glass board, a plurality of hinge means for supporting the document cover rotatably,
Wherein are arranged such that the document placing glass board facing the document cover, the document placing glass table top surface of the document placed on the original placing glass an upper surface of a table when the document cover is closed a pressing member for pressing the,
A sensor having a light emitting means and a light receiving means for detecting opening and closing of the document cover;
A recess for accommodating the sensor when the document cover is closed in a region of the document cover facing the sensor;
A light shielding portion that shields light between the light emitting means and the light receiving means when the document cover is closed in the recess,
The sensor protrudes higher than a lower end edge of the document cover when the document cover is opened to the maximum, and a gap between the plurality of hinge means and the adjacent hinge means is the height of the sensor. image reading apparatus characterized by being arranged to be smaller than the short dimension of the standard document of the smallest that can be read by placing size original placing glass table. An image forming apparatus comprising the image reading apparatus according to claim 1 .

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