JP2008019067A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device having a paper feeding cassette corresponding to various sizes of paper and removing a sensor etc. for detecting paper size from the bottom face of the paper feeding cassette to reduce the height of the paper feeding cassette. <P>SOLUTION: The paper feeding cassette 41 can be drawn from the side face of a device body, and a line sensor 81 is arranged above the paper feeding cassette 41 orthogonally to the drawing direction of the paper feeding cassette 41. On the side face of the paper feeding cassette 41, a distance detection means 82 for measuring a moving distance during storage operation of the paper feeding cassette 41 is provided. Based on detection results of the line sensor 81, the paper size in the direction orthogonal to the drawing direction of the paper feeding cassette 41 is calculated. A distance detected by the distance detection means 82 from a detection start point to a detection end point by the line sensor 81 during the storage operation of the paper feeding cassette 41 is determined as the paper size in the drawing direction of the paper feeding cassette 41. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus including a paper feed cassette housed in an apparatus main body.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, a paper feed cassette is often employed as a means for loading recording paper. Usually, the paper feed cassette can be pulled out from the side surface of the image forming apparatus main body. When replenishing paper, the paper cassette is pulled out to replenish paper, and then the paper cassette is pushed back and stored.

  In general, the paper feed cassette can accommodate various sizes of paper, and a movable guide is provided in the paper feed cassette to regulate the side edge of the paper according to the size of the paper. .

Further, the paper feed cassette is provided with a plurality of sensors for detecting the size of the paper and a drive substrate for driving the sensors. The sensor is provided with at least a sensor that detects the size of the paper in the vertical direction and a sensor that detects the size of the paper in the horizontal direction. Further, these sensors and the drive substrate are provided on the bottom surface of the paper feed cassette (see Patent Document 1).
Japanese Utility Model Publication No. 1-99823

  However, when the sensor and the drive substrate are provided on the bottom surface of the paper feed cassette, the height of the paper feed cassette increases accordingly, which causes an increase in the height of the image forming apparatus. However, in the configuration of the conventional sensor and drive board, it is essential to provide them on the bottom surface of the paper feed cassette, so the position of the sensor and drive board cannot be changed. In addition, in the case of a specification that accommodates various sizes of paper in one paper feed cassette, a sensor that detects the size of the paper is essential.

  The present invention provides an image forming apparatus in which the height of a paper feed cassette is reduced by removing a sensor for detecting the paper size from the bottom surface of the paper feed cassette in a paper feed cassette corresponding to various sizes of paper. For the purpose.

  In order to achieve the above object, the present invention provides an image forming apparatus comprising an apparatus main body and a paper feed cassette accommodated in the apparatus main body, wherein the paper feed is provided in the apparatus main body above the paper feed cassette. Provided is an image forming apparatus provided with one or more line sensors for detecting the size of sheets stacked in a cassette.

  In the image forming apparatus, the sheet cassette can be pulled out from a side surface of the apparatus body, and the line sensor is provided so as to be orthogonal to a direction in which the sheet cassette is pulled out. A distance detecting means for measuring a moving distance during the storing operation of the sheet cassette, and calculating a sheet size in a direction orthogonal to a pulling direction of the sheet cassette from a detection result of the line sensor, The size of the paper in the paper cassette pull-out direction is the distance detected by the distance detection means from the detection start point to the detection end point of the line sensor during the storage operation of the paper feed cassette.

  The distance detecting means includes a roller that rotates as the sheet feeding cassette moves, a pulse plate that enables measurement of the number of rotations of the roller, and a sensor that counts the number of pulses of the pulse plate. be able to.

  According to the present invention, by using the line sensor provided above the paper feed cassette to detect the paper size, a sensor for detecting the paper size can be excluded from the bottom surface of the paper feed cassette. The height of the paper feed cassette can be reduced.

  Further, according to the present invention, by using the line sensor and the distance detecting means, it is possible to eliminate a sensor or the like for detecting the paper size from the bottom surface of the paper feed cassette, and to reduce the height of the paper feed cassette. Can do.

  By reducing the height of the paper feed cassette, the height of the entire image forming apparatus can be reduced.

  FIG. 1 is a schematic view of an image forming apparatus of the present invention. The main body housing (device main body) 1 includes an upper housing 11, a lower housing 13, and a connection housing 12 positioned therebetween. On the upper housing 11, the document conveying unit 2 placed so as to be freely opened and closed is attached.

  The document transport unit 2 includes a document feed tray 21, a document transport unit body 22, a document discharge tray 23, and a document cover 24. The document discharge tray 23 is integrally formed as a part of the upper surface of the document cover 24. A document feed tray 21 is disposed at the upstream end on the extension of the document transport path d, and a document discharge tray 23 is disposed at the downstream end. A pickup roller 22a, a conveyance roller pair 22b, a registration roller pair 22c, and a discharge roller pair 22d are provided in order from the upstream side in the document conveyance direction in the document conveyance path d in the document conveyance unit main body 22. An image reading unit 25 is provided between the registration roller pair 22c and the discharge roller pair 22d. An image document (not shown) set on the document feed tray 21 with its image surface facing upward is conveyed along the conveyance path d by the rollers when a copy start button (not shown) is turned on, and an intermediate image reading unit. At 25, an image is read by the exposure unit 3.

  The exposure unit 3 is built in the upper housing 11. The exposure unit 3 includes an exposure lamp 31 and a reflecting plate 32, a first mirror 33, a second mirror 34, a third mirror 35, a condenser lens 36, and an image sensor (for example, a line type CCD) 37. The exposure lamp 31 and the first mirror 33 are mounted on a first carriage (not shown), and the second mirror 34 and the third mirror 35 are mounted on a second carriage (not shown). When reading a document image by a so-called sheet-through method, the first carriage moves directly below the image reading unit 25, and the light irradiation light from the exposure lamp 31 exposes the moving document. Irradiation light reaches the CCD 37 through the first mirror 33, the second mirror 34, the third mirror 35, and the condenser lens 36, and is read out as an electric signal through a photoelectric conversion process. On the other hand, when the original image is read by the original fixing method, the original image placed on the original placement plate 26 is subjected to reading scanning by the exposure unit 3 to be reduced and imaged on the CCD 37 and subjected to photoelectric conversion processing. After that, it is read to become an electric signal.

  In the lower housing 13, the paper feeding unit 4, the image forming unit 5, and the fixing device 6 are built. The paper feed unit 4 will be described first. A paper feed cassette 41 containing paper P is disposed below the lower housing 13, and the paper P is sent out one by one by a roller 42 to the conveyance path. Further, an openable / closable paper feed tray 43 is provided at the lower left portion of the lower housing 13, and the paper P is placed on the lower tray 13, so that the paper is conveyed one by one by the rollers 44 as described above. Sent to the road.

  Next, the image forming unit 5 will be described. The image forming unit 5 includes a photosensitive drum 51 and a charger 52, an optical scanning unit 53, a developing device 54, a transfer roller 55, and a cleaning device 56 disposed around the photosensitive drum 51. The photosensitive drum 51 rotates clockwise. First, the surface of the photosensitive drum 51 is uniformly charged by the charger 52. Next, the surface of the photosensitive drum 51 is irradiated with laser light from the optical scanning unit 53, the charge corresponding to the image portion or the background portion is erased, and an electrostatic latent image is formed on the surface of the photosensitive drum 51. . Then, the developing device 54 supplies toner to the electrostatic latent image on the photosensitive drum 51, and the electrostatic latent image is visualized.

  When the photosensitive drum 51 further rotates and the toner image comes to a position facing the transfer roller 55, the paper P is conveyed between the photosensitive drum 51 and the transfer roller 55 accordingly. At this time, the toner image on the photosensitive drum 51 is transferred onto the paper P by applying a voltage having a polarity opposite to the charging polarity of the toner to the transfer roller 55. Residual toner that has not been transferred onto the photosensitive drum 51 is removed from the photosensitive drum 51 by the cleaning device 56. On the other hand, the paper P onto which the toner image has been transferred is conveyed to the fixing device 6 described above, where the toner image is heated and pressurized to be fixed on the paper, and discharged to the paper discharge trays 7a and 7b through the paper discharge path. Is done.

  Next, a mechanism for detecting the size of the paper loaded in the paper feed cassette 41 in the image forming apparatus will be described in detail. FIG. 2 is a top view showing an example of a detailed configuration around the paper feed cassette, and FIG. 3 is a cross-sectional view taken along line AA of FIG.

  The paper feed cassette 41 can be pulled out from the side surface of the lower housing 13. The side surface may be any of the front, back, right side, and left side. In addition, a paper feed cassette storage portion 46 is provided in the lower housing 13, and the paper feed cassette storage portion 46 includes a bottom surface portion 46 a on which the paper feed cassette 41 is placed and a core formed above the bottom surface portion 46 a. It is comprised from character-shaped side wall part 46b. The paper feed cassette 41 is stored in the paper feed cassette storage unit 46. The paper feed cassette 41 can be pulled out from the opening surface of the side wall portion 46b, and at this time, the side wall portion 46b serves as a guide. Further, when storing the paper feed cassette 41, the paper feed cassette 41 is pushed in until the rear end of the paper feed cassette 41 comes into contact with the rear end face of the side wall portion 46b.

  In the paper feed cassette 41, movable guides 45 are provided at three locations for regulating the side edges of the paper according to the size of the paper. The guides 45a and 45b oppose each other and regulate the paper in the width direction. The guide 45c regulates the trailing edge of the sheet with respect to the transport direction. These guides 45 fix the position of the paper in the paper feed cassette 41. The mechanism for moving the guide 45 can employ a conventional technique. For example, a mechanism for sliding the guide 45 or a mechanism for attaching and detaching the guide 45 to a predetermined position can be used.

  Further, in the main body housing 1 (here, the lower housing 13) above the paper feed cassette 41, a CCD (Charge Coupled Device) or CIS (Contact Image Sensor) that detects the size of the paper loaded in the paper feed cassette 41, etc. A line sensor 81 is provided. The line sensor 81 is provided so as to be orthogonal to the drawing direction of the paper feed cassette 41. The line sensor 81 is provided in the vicinity of the front surface of the main body housing 1 so as to be detached from the upper side of the sheet when the sheet cassette 41 is stored. The length of the line sensor 81 only needs to be longer than the paper size that can be accommodated in the paper feed cassette 41. For example, the length of the line sensor 81 can be longer than the length of the paper feed cassette 41 in the pull-out direction as shown in FIG. .

  If this line sensor 81 is used, when the paper feed cassette 41 loaded with paper is stored in the paper feed cassette storage section 46, the paper passing through the line sensor 81 is detected to detect the paper feed cassette 41. It is possible to calculate the size of the paper in the direction orthogonal to the drawing direction. Further, by providing the line sensor 81 in the main body housing 1, an empty space in the main body housing 1 can be used. Further, by not providing the line sensor 81 in the paper feed cassette 41, the height of the paper feed cassette 41 can be reduced.

  In the vicinity of the rear end of the outer surface of the paper feed cassette 41, distance detection means 82 for measuring the moving distance during the storage operation of the paper feed cassette 41 is provided. The distance detection means 82 includes a shaft 82d protruding from the outer surface of the paper feed cassette, a roller 82a that is rotatably attached to the shaft 82d and rotates with the movement of the paper feed cassette 41, and a roller 82a provided outside the roller 82a. A pulse plate 82b that rotates to measure the number of rotations of the roller 82a, and a sensor (a reflective optical sensor in FIGS. 2 and 3) 82c that is provided outside the pulse plate 82b and counts the number of pulses of the pulse plate 82b; It has.

  When the paper feed cassette 41 provided with the distance detecting means 82 is stored in the paper feed cassette storage 46, the roller 82a rolls on the side wall 46b, and the roller 82a and the pulse plate 82b rotate. At this time, the sensor 82c counts the number of pulses.

  Using the distance detection means 82 and the line sensor 81, when the paper feed cassette 41 loaded with paper is stored in the paper feed cassette storage section 46, the first end of the paper passing under the line sensor 81 is detected. Detection is performed as a detection start point, and the end of the sheet passing under the line sensor 81 is detected as a detection end point. Then, the movement distance of the roller 82a is calculated from the number of pulses counted by the sensor 82c from the detection start point to the detection end point, and this movement distance is set as the paper size in the pulling-out direction of the paper feed cassette 41.

  As described above, by using the distance detection unit 82 and the line sensor 81, the size of the sheet in the pulling-out direction of the sheet feeding cassette 41 can be calculated. Further, by providing the distance detecting means 82 on the outer surface of the paper feed cassette 41, an empty space in the main body housing 1 can be used. Furthermore, by not providing the distance detection means 82 on the bottom surface of the paper feed cassette 41, the height of the paper feed cassette 41 can be reduced.

  The distance detecting means 82 is not particularly limited as long as it can measure the movement distance of the sheet feeding cassette. FIG. 4 is a front view of another distance detecting means and its periphery. As shown in FIG. 4, the sensor 82e used for the distance detecting means 82 'may be a transmissive optical sensor. At this time, a hole for measuring the number of pulses may be provided in the pulse plate 82f.

  It should be noted that the paper size can be detected by using two or more line sensors instead of the line sensor 81 and the distance detecting means 82 described above. Specifically, in a state in which the paper feed cassette 41 is housed in the paper feed cassette housing 46, a line sensor extending in the vertical direction of the paper and a line sensor extending in the horizontal direction above the stacked paper. And are orthogonal to each other. With this configuration, each line sensor can detect the vertical size and the horizontal size of the paper.

  The present invention can be used in an image forming apparatus that employs a paper feed cassette corresponding to paper of various sizes.

1 is a schematic view of an image forming apparatus of the present invention. FIG. 6 is a top view illustrating an example of a detailed configuration around a paper feed cassette. It is the sectional view on the AA line of FIG. It is a front view of another distance detection means and its periphery.

Explanation of symbols

1 Body housing (device body)
41 Feed cassette 81 Line sensor 82 Distance detection means 82a Roller 82b, 82f Pulse plate 82c, 82e Sensor

Claims (3)

In an image forming apparatus comprising an apparatus main body and a paper feed cassette stored in the apparatus main body,
One or more line sensors for detecting the size of the paper stacked in the paper feed cassette are provided in the apparatus main body above the paper feed cassette. The paper feed cassette can be pulled out from the side of the apparatus body,
The line sensor is provided so as to be orthogonal to the pulling-out direction of the paper feed cassette,
Provided on the side surface of the paper feed cassette is a distance detection means for measuring a moving distance during the storage operation of the paper feed cassette;
Calculating the size of the paper in the direction perpendicular to the pull-out direction of the paper feed cassette from the detection result of the line sensor;
The size of the sheet in the pull-out direction of the paper feed cassette is a distance detected by the distance detection unit from the detection start point to the detection end point of the line sensor during the storage operation of the paper feed cassette. The image forming apparatus according to claim 1.   The distance detecting means includes a roller that rotates as the sheet feeding cassette moves, a pulse plate that enables measurement of the number of rotations of the roller, and a sensor that counts the number of pulses of the pulse plate. The image forming apparatus according to claim 2.

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