JP6281438B2 - Paper size detection device, image forming device - Google Patents

Description

  The present invention relates to a paper size detection apparatus and an image forming apparatus that detect a paper size that is conveyed on a paper conveyance path.

  In the image forming apparatus, the size of the paper loaded in the paper feed cassette is detected by the position of a cursor or dial provided in the paper feed cassette, or recognized by the user inputting on the panel. However, if the paper size of the actually loaded paper and the paper size recognized by the image forming apparatus are different due to, for example, a cursor or dial setting error or a panel input error, JAM (paper jam) or image Formation failure is caused.

  For this reason, in Patent Document 1 below, the paper passage time is measured by a sensor arranged in the conveyance path, and the paper length in the conveyance direction is determined based on the measured time.

  In Patent Document 2 below, the paper width is detected using a thermistor installed in the fixing unit. In this method, since the temperature rise of the heater roller in the fixing unit is different between the area where the paper is passing and the area where the paper is not passing, the temperature rise time assumed for the recognized paper size and the thermistor are used. When the temperature rise time of the heater roller is different, it is determined that the paper size is inappropriate.

Japanese Patent Laid-Open No. 10-20718 JP 2007-232831 A

  However, the method described in Patent Document 1 has not been performed until the paper width is detected. Further, the method described in Patent Document 2 is difficult to actually use because the detection accuracy of the thermistor and parameters such as paper thickness affect the detection result.

  SUMMARY An advantage of some aspects of the invention is that it provides a paper size detection device and an image forming apparatus that can solve the above-described problems.

In order to achieve such an object, the paper size detection device of the present invention is:
A5 vertical paper, A5 horizontal paper, B5 vertical paper, B5 horizontal paper, A4 vertical paper, A4 horizontal paper, B4 vertical paper, and A3 vertical paper can be rotated to a paper transport path that can transport A rotating body arranged in
A first actuator disposed at a position pushed all the sheets conveyed the sheet conveying path extending from the side surface of the rotating body,
The first actuator is spaced apart in the axial direction of the rotating body and extends from the side surface of the rotating body, and is disposed at a position where it is pushed by all the sheets other than the A5 vertical sheet transported through the sheet transport path. Two actuators;
Positioning means for positioning the rotating body at an initial position;
Paper size determination means for determining the size of the paper transported through the paper transport path based on the time from when the rotating body rotates from the initial position to when the rotating body returns to the initial position;
With
The length of the second actuator is longer than the length of the first actuator , and is provided at the same position in the circumferential direction of the rotating body.
The present invention also provides:
An urging means for urging the rotating body toward the initial position is provided.
The present invention also provides:
The second actuator is configured such that the length of the B5 vertical paper in the conveyance direction is L1, the length of the A5 vertical paper in the conveyance direction is L2, and the second actuator pressed by the paper on the paper conveyance path. When the moving distance is L3 and the moving distance of the first actuator pushed by the paper on the paper transport path is L4, the following equation (1) is satisfied.
(L1-L2)> (L3-L4) (Equation 1)
The present invention also provides:
The paper size determining means includes
A detected object extending from a side surface of the rotating body;
A sensor for detecting the detected object;
And determining means for determining the paper size based on the detection result of the sensor.
The present invention also provides:
The determination unit determines a paper size by comparing a rotation time of the rotating body determined in advance for each paper size and a rotation time of the rotating body specified based on a detection result of the sensor. It is characterized by.
The present invention also provides:
A conveyance speed adjusting means for adjusting a sheet conveyance speed in the sheet conveyance path is provided.
The present invention also provides:
The transport speed adjusting means adjusts the paper transport speed to a normal paper transport speed during first printing after the paper cassette is opened and closed.
The image forming apparatus according to the present invention includes:
The paper size detecting device is provided.

  According to the present invention, the paper size other than A5 portrait can be specified based on the rotation time of the rotating body by the second actuator, and the A5 portrait paper size can be specified based on the rotation time of the rotating body by the first actuator. All sizes including the sheet width of the sheet conveyed through the sheet conveyance path can be recognized based on the rotation time of the rotating body.

1 is a configuration diagram of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an outline of a configuration of a paper size detection device provided in the image forming apparatus of FIG. 1. FIG. 6 is a diagram illustrating a relationship between a sheet conveyance path and a sheet size. It is a perspective view which shows the outline of a structure of a rotary body. It is a side view which shows the 1st actuator of FIG. It is a side view which shows the 2nd actuator of FIG. It is a 1st side view which shows operation | movement of a rotary body. It is a 2nd side view which shows operation | movement of a rotary body. It is a 3rd side view which shows operation | movement of a rotary body.

<Embodiment>
[Configuration of Image Forming Apparatus 1]
First, with reference to FIG. 1, the configuration of an image forming apparatus 1 according to an embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 1, the image forming apparatus 1 according to the present embodiment includes a document reading unit 2, a document feeding unit 3, a main body unit 4, a stack tray 5, and an operation panel unit 6.
The document reading unit 2 is disposed above the main body unit 4, and the document feeding unit 3 is disposed above the document reading unit 2. The stack tray 5 is disposed on the recording paper discharge port 41 side provided in the main body section 4, and the operation panel section 6 is disposed on the front side of the main body section 4.

  The document reading unit 2 includes a scanner 21, a platen glass 22, and a document reading slit 23. The scanner 21 includes an exposure lamp, a CCD (Charge Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor) imaging sensor, and the like, and is configured to be movable in the document transport direction by the document feeder 3. The platen glass 22 is an original table made of a transparent member such as glass. The document reading slit 23 has a slit formed in a direction orthogonal to the document transport direction by the document feeder 3.

When reading a document placed on the platen glass 22, the scanner 21 is moved to a position facing the platen glass 22 and reads the document while scanning the document placed on the platen glass 22 to obtain image data. The acquired image data is output to the main unit 4.
When reading the document conveyed by the document feeding unit 3, the scanner 21 is moved to a position facing the document reading slit 23, and the document is conveyed by the document feeding unit 3 through the document reading slit 23. The document is read in synchronization with the operation to acquire image data, and the acquired image data is output to the main body unit 4.

  The document feeding unit 3 includes a document placement unit 31, a document discharge unit 32, and a document transport mechanism 33. The originals placed on the original placement unit 31 are sequentially fed out one by one by the original conveyance mechanism 33, conveyed to a position facing the original reading slit 23, and then discharged to the original discharge unit 32. The document feeding unit 3 is configured to be retractable, and the upper surface of the platen glass 22 can be opened by lifting the document feeding unit 3 upward.

The main body 4 includes the image forming unit 7, and includes a paper feeding unit 42, a paper conveyance path 43, a conveyance roller pair 44, and a discharge roller pair 45. The paper feed unit 42 includes a plurality of paper feed cassettes 421 that store recording papers of different sizes or orientations, and a paper feed roller 422 that feeds the recording papers one by one from the paper feed cassette 421 to the paper transport path 43. Yes.
The paper feed roller 422, the transport roller pair 44, and the discharge roller pair 45 function as a transport unit. The recording paper is conveyed by this conveyance unit. The recording paper fed to the paper conveyance path 43 by the paper supply roller 422 is conveyed to the image forming unit 7 by the conveyance roller pair 44.
Then, the recording paper on which recording is performed by the image forming unit 7 is discharged to the stack tray 5 by the discharge roller pair 45.

The operation panel unit 6 is a low-priced display unit 61 such as a 7-segment LED, an operation mode switching button such as a start key, numeric keypad, copying / fax transmission / scanner, and printing, transmission, reception, storage, or recording. An input unit 62 including buttons and a touch panel for giving instructions is provided. The operation panel unit 6 receives an instruction input from the input unit 62 of the image forming apparatus 1 by the user.
Further, the operation panel unit 6 accepts an authentication input such as a password by the user.

The image forming unit 7 includes a photosensitive drum 71, an exposure unit 72, a developing unit 73, a transfer unit 74, and a fixing device 8. The exposure unit 72 is an optical unit including a laser device, a mirror, a lens, and the like. The exposure unit 72 outputs light based on image data to expose the photosensitive drum 71, and an electrostatic latent image is formed on the surface of the photosensitive drum 71. Form. The developing unit 73 is a developing unit that develops the electrostatic latent image formed on the photosensitive drum 71 using toner, and forms a toner image based on the electrostatic latent image on the photosensitive drum 71.
The transfer unit 74 transfers the toner image formed on the photosensitive drum 71 by the developing unit 73 onto a recording sheet. The fixing device 8 heats the recording paper on which the toner image is transferred by the transfer unit 74 to fix the toner image on the recording paper.

  Next, the paper size detection device 80 provided in the image forming apparatus 1 will be described. FIG. 2 is a diagram showing an outline of the configuration of the paper size detection device 80. FIG. 3 is a diagram showing the relationship between the paper transport path 43 and the paper size. The reference points shown in FIG. 3 are tentatively shown for comparing the sizes of the respective paper sizes, and the dimensions of the respective papers when the upper left corner is aligned are indicated based on the reference points. ing.

  The paper sizes used in the image forming apparatus 1 include A5 portrait, B5 portrait, A5 landscape, A4 portrait, B4 portrait, B5 landscape, A3 portrait, and A4 landscape. In the A5 length, the length in the transport direction in the paper transport path 43 is 210 mm, and the width is 148 mm. In the B5 length, the length in the transport direction in the paper transport path 43 is 257 mm, and the width is 182 mm. On the side of A5, the length in the transport direction in the paper transport path 43 is 148 mm, and the width is 210 mm. In the A4 length, the length in the transport direction in the paper transport path 43 is 297 mm, and the width is 210 mm. In the B4 length, the length in the transport direction in the paper transport path 43 is 364 mm, and the width is 257 mm. Next to B5, the length in the transport direction in the paper transport path 43 is 182 mm, and the width is 257 mm. In the A3 length, the length in the transport direction in the paper transport path 43 is 420 mm, and the width is 297 mm. On the A4 side, the length in the transport direction in the paper transport path 43 is 210 mm, and the width is 297 mm.

  The paper size detection device 80 is for detecting the size of the paper that is fed from the paper feed cassette 421 one by one by the paper feed roller 422 and conveyed by the conveyance roller pair 44. As shown in FIGS. 2 and 4, the paper size detection device 80 includes a rotating body 81, a detection target 82, a sensor 83, and a determination unit 84. The detected object 82, the sensor 83, and the determination unit 84 determine the size of the sheet conveyed through the sheet conveyance path 43 based on the time from when the rotating body 81 rotates from the initial position until it returns to the initial position. It constitutes size determination means.

  As shown in FIG. 4, the rotator 81 has a round bar shape, and is rotatably disposed in the paper conveyance path 43. A first actuator 811 and a second actuator 812 extend from the side surface of the rotating body 81.

  The first actuator 811 extends in a flat plate shape from the side surface of the rotator 81 at a position where the first actuator 811 is pressed by the A5 vertical sheet conveyed along the sheet conveyance path 43. The first actuator 811 continues until the trailing edge of the paper passes as shown by a two-dot chain line in FIG. 5 after the leading edge of the paper conveyed through the paper conveyance path 43 as shown by a solid line in FIG. Further, the contact position of the first actuator 811 that is in contact with the sheet is formed to move a distance L4 on the sheet conveyance path 43 in the sheet conveyance direction.

  The second actuator 812 extends in a flat plate shape from the rotation position at a position where the second actuator 812 is pushed by a sheet other than the A5 portrait conveyed along the sheet conveyance path 43. The first actuator 811 and the second actuator 812 are provided at the same position in the circumferential direction of the rotating body 81.

  The second actuator 812 waits for the trailing edge of the paper to pass as shown by the two-dot chain line in FIG. 6 after the leading edge of the paper conveyed through the paper conveyance path 43 as shown by the solid line in FIG. Further, the contact position of the second actuator 812 that is in contact with the sheet is formed to move a distance L3 on the sheet conveyance path 43 in the sheet conveyance direction.

  The second actuator 812 is formed longer than the first actuator 811. Specifically, for example, the second actuator 812 has a length in the conveyance direction of B5 vertical paper as L1 (see FIG. 3), a length in the conveyance direction of A5 vertical paper as L2 (see FIG. 3), and the like. The movement distance of the second actuator 812 pushed by the sheet on the sheet conveyance path 43 is L3 (see FIG. 6), and the movement distance of the first actuator 811 pushed by the sheet on the sheet conveyance path 43 is L4. (See FIG. 5), it can be formed so as to satisfy the following formula (1).

                    (L1-L2)> (L3-L4) (Equation 1)

  In this way, the difference between the time when the second actuator 812 is pushed by the A4 paper and the time when the first actuator 811 is pushed by the A5 paper (L3−L4) / V (V is the conveyance of the paper) Speed) is the difference between the time when the second actuator 812 is pushed by the B5 vertical paper and the time when the second actuator 812 is pushed by the A4 horizontal paper (L1-L2) / V (V is the paper conveyance speed) ) Can be smaller.

  Accordingly, when the time when the second actuator 812 is pushed by the A4 landscape paper is used as a reference, the time when the first actuator 811 is pushed by the A5 portrait paper is the second actuator 812 by the B5 portrait paper. It will be shorter than the time that is pressed.

  As a result, it is possible to distinguish between the measurement time when the first actuator 811 is pushed by the A5 vertical paper and the measurement time when the second actuator 812 is pushed by the B5 vertical paper, and B5 vertical and A5 The length of the vertical sheet in the conveyance direction can be reliably divided and detected.

  Note that the initial position at which the first actuator 811 and the second actuator 812 first contact the sheet is set by positioning means (not shown). That is, the positioning means positions the rotating body 81 at the initial position.

  The detected object 82 extends in a flat plate shape from the side surface of the rotating body 81. The sensor 83 is for detecting the detected object 82. The sensor 83 outputs an off signal when the detected object 82 is located at the initial position, the rotating body 81 rotates in the paper transport direction, and the detected object 82 moves from the initial position toward the sensor 83. When it is moved to, an ON signal is output.

  The determination unit 84 measures the time from when the ON signal is input from the sensor 83 to when the OFF signal is input, and determines the size of the paper transported through the paper transport path 43 based on the measurement time.

  Next, the operation of the paper size detection device 80 that determines the size of the paper conveyed through the paper conveyance path 43 will be described.

  The paper stored in the paper feed cassette 421 is fed from the paper feed cassette 421 to the paper transport path 43 one by one by the paper feed roller 422, and is transported through the paper transport path 43 by the transport roller pair 44.

  When the size of the paper transported through the paper transport path 43 is A5 vertical, the leading edge of the paper transported through the paper transport path 43 is the first actuator 811 and the first actuator on the paper transport path 43 as shown in FIG. When the arrangement position of the second actuator 812 is reached, the first actuator 811 is pressed against the paper. When the first actuator 811 is pushed by the paper, the rotating body 81 starts to rotate in the paper transport direction.

  When the size of the paper transported through the paper transport path 43 is other than A5 portrait, the leading edge of the paper transported through the paper transport path 43 is the first actuator 811 on the paper transport path 43 and When the arrangement position of the second actuator 812 is reached, the first actuator 811 and the second actuator 812 are pressed against the sheet. When the first actuator 811 and the second actuator 812 are pushed by the paper, the rotating body 81 starts to rotate in the paper transport direction from the initial position.

  As the rotator 81 rotates in the paper transport direction, the detected object 82 extending from the side surface of the rotator 81 rotates around the rotator 81. When the rotating body 81 starts to rotate in the paper transport direction, an ON signal is input from the sensor 83 to the paper size determination unit 82.

  When the size of the sheet conveyed through the sheet conveyance path 43 is A5 length, the rotating body 81 rotates in the reverse direction by its own weight when the first actuator 811 is released from the sheet as shown in FIG. To return to the original initial position. When the size of the sheet conveyed through the sheet conveyance path 43 is other than A5 portrait, the rotating body 81 rotates until the second actuator 812 is released from the sheet as shown in FIG. Rotate in the direction to return to the original initial position.

  When the rotating body 81 returns to the original position, the detected object 82 returns to the initial position, and an off signal is input from the sensor 83 to the paper size determining means 82. The paper size determination unit 82 measures the time from when the ON signal is input from the sensor 83 to when the OFF signal is input, and determines the paper size based on the measurement time.

  When the paper size is B5 vertical, A5 horizontal, A4 vertical, B4 vertical, B5 horizontal, A3 vertical, A4 horizontal, the length of each paper size in the transport direction is different. For this reason, the time from when the second actuator 812 is pushed to when the rotating body 81 returns to the original position is different, and the measurement time by the paper size determination means 82 is also different for each paper size.

  For example, as shown in FIG. 3, the length in the A5 horizontal transport direction is 148 mm, the length in the B5 horizontal transport direction is 182 mm, the length in the A4 horizontal transport direction is 210 mm, and the length in the B5 vertical transport direction is 257 mm, A4 vertical transport direction length is 297 mm, B4 vertical transport direction length is 364 mm, and A3 vertical transport direction length is 420 mm. For this reason, the measurement time by the paper size determination means 82 becomes a large value in the order of A5 horizontal, B5 horizontal, A4 horizontal, B5 vertical, A4 vertical, B4 vertical, and A3 vertical.

  For this reason, the paper size determination means 82 is transported through the paper transport path 43 by determining which paper size of the predetermined time for each paper size corresponds to the actual measurement time. Specify the paper size.

  When the paper size is A5 portrait, the detected body 82 returns to the initial position when the first actuator 811 is released. For this reason, the detected object 82 does not return to the initial position until the second actuator 812 is released. The paper sizes are B5 vertical, A5 horizontal, A4 vertical, B4 vertical, B5 horizontal, A3 vertical, and A4 horizontal. The measurement time by the paper size determination means 82 can be varied. For this reason, the paper size determination unit 82 determines whether the actual measurement time corresponds to a predetermined time for the A5 vertical paper size, so that the paper transported through the paper transport path 43 is A5 vertical. It is determined whether it is a paper size.

With the configuration described above, the following effects can be obtained.
According to the present embodiment, a paper size other than A5 portrait can be specified based on the rotation time of the rotating body 81 by the second actuator 812, and the A5 portrait paper size can be specified based on the rotation time of the rotating body 81 by the first actuator 811. Can be identified. For this reason, all sizes including the sheet width of the sheet conveyed through the sheet conveyance path 43 can be recognized. As a result, it can be determined that the paper size actually differs between the paper actually stored in the paper feed cassette 421 and the paper recognized by the image forming apparatus 1, and JAM and image formation defects can be reduced.

  In the above embodiment, the case where the paper size determination unit specifies the rotation time of the rotating body from the time when the on signal is input from the sensor to the time when the off signal is input is described. The method is arbitrary and is not limited thereto. Also, the length and shape of the first actuator 811 and the second actuator 812 are arbitrary as long as the amount of rotation of the rotating body can be changed for each paper transport size.

  Also, during the first print after opening and closing of the paper feed cassette 421, the paper transport speed tends to be faster than the normal paper transport speed. It tends to occur. For this reason, it may be configured to include a transport speed adjusting means so that the paper is transported at a normal paper transport speed even during the first print after the paper feed cassette 421 is opened and closed. The conveyance speed adjusting unit adjusts the sheet conveyance speed in the sheet conveyance path 43 during the first print after opening and closing of the paper feed cassette 421 so that the sheet conveyance speed becomes a normal sheet conveyance speed of, for example, about 100 mm / sec.

  Moreover, the 1st actuator 811 and the 2nd actuator 812 should just be formed in mutually different length, and are not limited to the structure of the said embodiment. In the above-described embodiment, the case where the rotating body 81 rotates by its own weight and returns to the initial position has been described. However, the rotating body 81 may be biased by the biasing means and return to the initial position. In this configuration, the rotating body 81 is biased toward the initial position by a biasing means (not shown), and when the sheet passes through the first actuator 811 and the second actuator 812, the rotating body 81 is Return to the initial position.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Original reading part 3 Original feeding part 4 Main body part 5 Stack tray 6 Operation panel part 7 Image forming part 8 Fixing device 21 Scanner 22 Platen glass 23 Original reading slit 31 Original placement part 32 Original discharge part 33 Original Transport mechanism 41 Discharge port 42 Paper feed unit 43 Paper transport path 44 Transport roller pair 45 Discharge roller pair 71 Photosensitive drum 72 Exposure unit 73 Development unit 74 Transfer unit 80 Paper size detection device 81 Rotating body 82 Detected object 83 Sensor 84 Determination Means 421 Paper feed cassette 422 Paper feed roller 811 First actuator 812 Second actuator

Claims (8)

A5 vertical paper, A5 horizontal paper, B5 vertical paper, B5 horizontal paper, A4 vertical paper, A4 horizontal paper, B4 vertical paper, and A3 vertical paper can be rotated to a paper transport path that can transport A rotating body arranged in
A first actuator disposed at a position pushed all the sheets conveyed the sheet conveying path extending from the side surface of the rotating body,
The first actuator is spaced apart in the axial direction of the rotating body and extends from the side surface of the rotating body, and is disposed at a position where it is pushed by all the sheets other than the A5 vertical sheet transported through the sheet transport path. Two actuators;
Positioning means for positioning the rotating body at an initial position;
Paper size determination means for determining the size of the paper transported through the paper transport path based on the time from when the rotating body rotates from the initial position to when the rotating body returns to the initial position;
With
The paper size detection device, wherein the length of the second actuator is longer than the length of the first actuator , and is provided at the same position in the circumferential direction of the rotating body.   The paper size detection apparatus according to claim 1, further comprising a biasing unit that biases the rotating body toward the initial position. The second actuator is configured such that the length of the B5 vertical paper in the conveyance direction is L1, the length of the A5 vertical paper in the conveyance direction is L2, and the second actuator pressed by the paper on the paper conveyance path. 2. The apparatus according to claim 1, wherein when the moving distance is L3 and the moving distance of the first actuator pushed by the sheet on the sheet conveying path is L4, the following equation (1) is satisfied. 2. The paper size detection apparatus according to 2.
(L1-L2)> (L3-L4) (Equation 1) The paper size determining means includes
A detected object extending from a side surface of the rotating body;
A sensor for detecting the detected object;
The paper size detection apparatus according to claim 1, further comprising a determination unit that determines a paper size based on a detection result of the sensor.   The determination unit determines a paper size by comparing a rotation time of the rotating body determined in advance for each paper size and a rotation time of the rotating body specified based on a detection result of the sensor. The paper size detection device according to claim 4.   The paper size detection apparatus according to claim 1, further comprising a conveyance speed adjusting unit that adjusts a paper conveyance speed in the paper conveyance path.   The paper size detection device according to claim 6, wherein the transport speed adjusting unit adjusts the paper transport speed to a normal paper transport speed during first printing after opening and closing of the paper feed cassette.   An image forming apparatus comprising the paper size detection device according to claim 1.

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