JPH05105265A - Paper sheet size detecting device - Google Patents

Abstract

PURPOSE:To provide an inexpensive paper sheet-size detecting device which is capable of correct detection of the size of a lot of paper sheets with a simple constitution. CONSTITUTION:Five recessed parts 34a-34e are provided in the side surface part of a cassette body 31. A microswitch 35 is arranged on a printer body side opposite to these recessed parts 34a-34e. Photosensors 36, 37 are arranged in parallel in the position opposite to a paper sheet 29 at the upper part of a paper sheet supplying cassette 18 on the printer body side. The photosensor 36 is arranged in the position opposite to the right side of the end part of the paper sheet 29 of the minimum length in the paper sheet supplying direction (A). The other photosensor 37 is arranged in the position which is distant by one half of the maximum length of paper sheet 29 having the maximum length in the paper sheet supplying direction (A), i.e., to the left side of the line 39a in the figure, and in the position which is distant by twice of the minimum length of the paper sheet 29 having the minimums length in the paper sheet supplying direction (A), i.e., to the right side of the line 39b in the figure, and in the position not corresponding to the end part of the direction (B) perpendicular to the paper supplying direction (A) of the paper sheet 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper size detecting device for detecting the size of a paper stored in a paper feed cassette capable of containing a plurality of papers of different sizes, and particularly to an image of a copying machine, a printer, a facsimile or the like. The present invention relates to a sheet size detecting device applied to a sheet feeding device of a forming apparatus.

[0002]

2. Description of the Related Art Generally, in an image forming apparatus such as a copying machine, a sheet feeding cassette detachably attached to a main body of the apparatus is used as a sheet feeding device. As this paper feed cassette, there are a dedicated cassette corresponding to only a predetermined fixed size paper among A series paper such as JIS A3 and A4 or B series paper such as B4 and B5, and a plurality of sizes. There is a cassette called a universal cassette that can handle even the sheets of paper.

By the way, in a paper feeding device using such a cassette, when using papers of different sizes or different orientations, the dedicated cassette is replaced every time it is necessary, or
Even when the universal cassette was used, the size and orientation of the detection material had to be changed or changed at the same time.

On the other hand, a sheet size detecting device for identifying the sheet size by moving the detecting material along with the movement of the guide member and detecting the detecting material with a detecting switch (Japanese Patent Laid-Open No. 63-66030). ), A light emitting unit and a light receiving unit that are vertically opposed to each other with the paper sandwiched therebetween, light is emitted only to a portion that is not blocked by the paper, and the paper size is detected by the photoelectric exchange output of the light receiving unit (Patent Document 1) Sho 60-111908
Issue gazette).

[0005]

However, in the paper size detecting device disclosed in Japanese Patent Laid-Open No. 63-66030, since the detection switch is provided in the cassette, the cassette itself becomes complicated and large. Further, since the apparatus main body and the cassette have to be electrically connected, in a cassette that is frequently taken in and out, there is a problem in terms of detection accuracy due to defective contacts and the like.

Further, in the paper size detection method disclosed in Japanese Patent Laid-Open No. 60-111908, it is impossible to discriminate paper sizes having the same width but different lengths in a universal cassette which accommodates a large number of paper sizes. There was a problem. Moreover, there is a possibility that the sizes of different papers having a close width may be erroneously detected.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an inexpensive paper size detecting apparatus which has a simple structure and can detect a large number of paper sizes with high accuracy. is there.

[0008]

A paper size detecting device according to the present invention is a paper size detecting device for detecting the size of a paper stored in a paper feed cassette detachably provided in an image forming apparatus main body. A timing information detection unit that is provided in the paper feed cassette and that represents timing information when the paper feed cassette is inserted into the image forming apparatus body; and the timing information that is provided on the image forming apparatus body side. Timing information detecting means for detecting the size of the sheet based on the timing information, and size information detecting means for detecting the size information of the sheet in the inserting direction based on the timing information. And a size detecting means for detecting the size.

Here, the timing information detection means is, for example, a plurality of convex portions provided on the side surface of the paper feed cassette corresponding to the paper size, and the timing information detection means is, for example, an image forming apparatus of the paper feed cassette. It can be configured by a sensor such as a micro switch that detects the convex portion when it is inserted into the main body.

With such a configuration, in the paper size detecting apparatus of the present invention, when the paper feed cassette is inserted into the main body of the image forming apparatus, the timing information detecting means detects the timing information on the paper feed cassette side. Based on this, the size information detecting means detects size information in the insertion direction of the paper, and the size of the paper is detected based on this size information.

Further, the paper size detecting device of the present invention is a paper size detecting device for detecting the size of a paper housed in a paper feed cassette detachably provided in the main body of the image forming apparatus. And timing information for detecting the timing information, which is provided on the image forming apparatus body side and is provided on the image forming apparatus body side. A detection unit, a first size information detection unit that is provided on the image forming apparatus main body side, and that detects size information in the insertion direction of the sheet based on the timing information, and a first size information detection unit that is provided on the image forming apparatus main body side , A second size that detects size information in a direction orthogonal to the paper insertion direction based on the timing information. And information detecting means, and a size detecting means for detecting the size of the paper on the basis of the first size information and the second size information.

In the paper size detecting device having such a configuration, when the paper cassette is inserted, the size information in the paper inserting direction and the size information in the direction perpendicular to the inserting direction are also detected. It is also possible to distinguish between portrait orientation and landscape orientation. In addition, "portrait"
Means a state in which the longitudinal direction of the paper is arranged so as to be aligned with the paper feeding direction, and "lateral" means a state in which the longitudinal direction of the paper is arranged so as to be orthogonal to the paper feeding direction.

Further, the paper size detecting device of the present invention is a paper size detecting device for detecting the size of the paper housed in a paper feed cassette detachably provided in the main body of the image forming apparatus. And an insertion speed information detection unit that is provided on the image forming apparatus main body side and that detects the insertion speed information. Information detecting means, paper edge detecting means provided on the image forming apparatus main body side and for detecting both edges of the paper along the insertion direction, time required for output change of the paper edge detecting means, and the insertion. And a size detecting means for detecting the size of the sheet in the inserting direction based on the speed information.

The insertion speed detection means is, for example, a black-and-white pattern provided on the side surface of the paper feed cassette, and the insertion speed detection means is composed of, for example, a reflection type photo sensor for detecting the black-and-white pattern.

In this paper size detecting device, when the paper feed cassette is inserted into the main body of the image forming apparatus, the insertion speed information detecting means detects the insertion speed information and the paper edge detecting means detects both end portions of the paper. Then, the size of the paper is detected based on the insertion speed information and the time required for the output of the paper edge detection unit to change.

Further, the paper size detecting device of the present invention is
A paper size detection device for detecting the size of paper stored in a paper feed cassette detachably provided in the image forming apparatus main body, the paper size detection device being provided in the paper feed cassette,
A plurality of sets of first detection holes that represent size information in the insertion direction of the paper feed cassette into the main body of the image forming apparatus; and a direction that is provided in the paper feed cassette and is orthogonal to the insertion direction of the paper. And a second detection hole indicating size information of the
A first size information detecting unit that detects the first size information by detecting the first detection hole, and a second size detection unit that is provided on the image forming apparatus main body side and that detects the second detection hole Second size information detecting means for detecting the size information of the sheet and size detecting means for detecting the size of the sheet based on the first size information and the second size information.

In this paper size detection device, the position of the detection hole to be closed differs depending on the size of the paper stored in the paper feed cassette. Therefore, it is possible to detect the paper size according to the detection status of the first detection hole and the second detection hole when the paper feed cassette is inserted.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 15 shows an overall schematic structure of an image forming apparatus, for example, a laser beam printer 11 using a paper size detecting apparatus according to an embodiment of the present invention.

The laser beam printer 11 is provided with a laser scanning device 12, and the laser scanning device 12 outputs a laser beam 13. The laser beam 13 output from the laser scanning device 12 repeatedly scans a predetermined exposure position 14a of the photosensitive drum 14 in its axial direction, that is, the main scanning direction. A charge corotron 15 is arranged slightly opposite to the exposure position 14a so as to face the photosensitive drum 14, and the surface of the photosensitive drum 14 is uniformly charged. By irradiating the laser beam 13 on the photosensitive drum 14 after the charging,
An electrostatic latent image corresponding to image information is formed on the drum surface. This electrostatic latent image is developed by the developing roll 16 on the drum surface on the downstream side of the exposure position 14a. The toner image formed by the development of the developing roller 16 moves to a position facing the transfer corotron 17 by the rotation of the photosensitive drum 14, and is electrostatically transferred onto a sheet (recording sheet) 29 here. Become.

The paper 29 is the laser beam printer 1
It is adapted to be stacked on a paper feed cassette 18 which is detachably arranged at the lower part of 1. The paper 29 arranged on the uppermost layer of the paper feed cassette 18 is sent out of the paper feed cassette 18 by the paper feed roller 19. The fed-out sheet 29 is conveyed by the conveying roll 20 along the path indicated by the broken line, and when it reaches the leading end of the registration roll 21, its progress is temporarily stopped. After this, an electromagnetic clutch (not shown) moves the registration roll 2 in synchronization with the rotational position of the photosensitive drum 14.
The rotation of No. 1 is started, whereby the paper 29 is stably conveyed at a constant speed. The paper sheet 29 passes between the photoconductor drum 14 and the transfer corotron 17 at a desired timing, and a toner image is transferred during this passage. The transferred sheet 29 is destaticized from its back surface by a destaticizing needle (not shown) arranged on the downstream side of the transfer corotron 17, and is peeled off from the drum surface. The peeled sheet 29 is conveyed on the conveying path 22 having a predetermined length to release the tension, and then the heat roll 2
The toner image is conveyed to a fixing device including a pair of the pressure roller 24 and the pressure roller 24, and the toner image is thermally fixed on the paper surface.

At the outlet side of the fixing device, a switching valve 25 for switching the conveying path of the sheet 29 after fixing is provided, and by the switching operation of this switching valve 25, the sheet 29 after fixing goes straight and the discharge roll 26. Is discharged in the first discharge direction by the device or is conveyed in an inverted U-shape in the device and is discharged by the discharge roll 2
The laser beam is ejected from the upper part of the laser beam printer 11 in the second ejection direction substantially opposite to the first ejection direction by means of 7. The toner image that has not been transferred to the paper 29 is removed from the drum surface by the cleaning device 28 arranged further downstream of the transfer corotron 17.

[Details of Paper Size Detection Device]

(First embodiment)

FIG. 1 shows a specific structure of the paper feed cassette 18. The paper feed cassette 18 includes a width direction guide member 32 and a paper feed direction guide member 33 in a cassette body 31. A pair of width direction guide members 32 are provided on both sides of the cassette body 31 so as to face each other, and along the grooves (not shown) provided at the bottom of the cassette body 31, the width direction guide members 32 (shown in the drawing). It is movable in the width direction (x direction) perpendicular to (A). The paper feed direction guide member 33 is movable in the front-rear direction (y direction) along the paper feed direction A of the paper 29 along a groove (not shown). By moving the width direction guide member 32 and the paper feed direction guide member 33, the paper feed cassette 18 can feed the paper 2 of each size A3 to A5 and B4 to B5.
9 can be accommodated.

On the side surface of the cassette body 31, a plurality of, for example, five recesses 34a to 34e are provided as timing information detection means, a part of which is enlarged and shown in FIG. The protrusions 34a to 34e on the cassette body 31 side
A micro switch 35 as a timing information detecting means is disposed on the printer body side in opposition to the.

The paper feed cassette 18 on the printer body side
Photo sensors 36 and 37 as size information detecting means are arranged in parallel at the upper part of the sheet at a position facing the sheet 29.

FIG. 3 shows the positional relationship of the microswitch 35, the photosensors 36 and 37, and the recesses 34a to 34e on the cassette body 31 side with respect to each size of the paper 29. The convex portions 34a to 34e are arranged corresponding to the end positions in the width direction of the sheets 29 of each size. When the paper feed cassette 18 is inserted into the printer body, the micro switch 35 comes into contact with each of the convex portions 34a to 34e to operate, and is repeatedly turned on and off.

One of the photosensors 36 is arranged at the end of the sheet 29 having the minimum length in the sheet feeding direction A, that is, at a position facing the right side of the straight line 38 in the drawing. The other photo sensor 37 is located at a position half the length of the sheet 29 having the maximum length in the sheet feeding direction A, that is, on the left side of the straight line 39a in the drawing, and 2 of the sheets 29 having the minimum length in the sheet feeding direction A. It is arranged at a position of a double length, that is, on the right side of the straight line 39b in the figure, and at a position that does not correspond to the end of the sheet 29 in the direction B perpendicular to the sheet feeding direction A.

FIG. 4 shows a laser beam printer 1 of this embodiment.
1 is a diagram showing the main part of the circuit configuration of the first control unit. This laser beam printer 11 has a CPU (central processing unit) 4
It has 0. The CPU 40 is connected to each unit of the device via a bus 41 such as a data bus. Of these, R
An OM (Read Only Memory) 42 is a memory that stores programs for performing various controls of the laser beam printer 11. A RAM (random access memory) 43 is a memory for temporarily storing various data required for controlling the laser beam printer 11.

In this embodiment, when the paper feed cassette 18 is inserted into the printer body, the outputs of the photosensors 36 and 37 change at both ends of the paper 29 parallel to the paper feed direction A. On the other hand, the micro switch 35 is provided with a convex portion 34 provided on a side surface portion of the cassette main body 31 in accordance with a paper size.
By sequentially contacting a to 34e, ON / OFF is repeated. Micro switch 35 and photo sensor 3
The output signals of 6 and 37 are respectively sent to the CPU 40.

The CPU 40 uses the micro switch 35.
Receiving the output signal of the photo sensor 36 and the output signal of the photo sensor 36,
The paper size is detected based on the program stored in the ROM 42. Further, the CPU 40 is a micro switch 37.
In response to the output signal of, the two sheets of paper 29 having the same width, for example, the case of A3 size paper and the case of horizontally storing A4 size paper are distinguished. The CPU 40 displays the detected size of the paper 29 on the display unit 4
4 is displayed. The display unit 44 is provided on an operation panel (not shown) on the printer body side.

In the paper size detecting apparatus of this embodiment, from the time when the paper feed cassette 18 is inserted into the printer main body,
By comparing the outputs of the micro switch 35 and the photosensors 36 and 37 until the insertion is completed, the size of the paper 29 and its orientation can be detected.

For example, FIGS. 5A to 5C show timing charts when the sheet size is detected when the A3 size sheet 29 is stored in the sheet feeding cassette 18.
When the micro switch 35 comes into contact with the convex portion 34a and is turned on for the first time, the photo sensor 36 is turned on at the same time. Therefore, the A3 size paper 29 or the A4 size paper 29 is used.
It is understood that the paper is accommodated in a horizontal direction, and since the photo sensor 37 is turned on at the same time as the photo sensor 36, it is detected that the paper 29 is A3 size.

In the timing charts of FIGS. 6A to 6C, it can be seen that the photo sensor 37 is not turned on from the start of the insertion of the paper feed cassette 18 to the end of the insertion, so that the paper 29 is laterally accommodated in A4 size. ..

In the timing charts of FIGS. 7A to 7C, the microswitch 35 comes into contact with the convex portion 34e, and 5
Since the photo sensor 36 is turned on at the same time when turned on for the second time and the photo sensor 37 is turned off to the end, it can be seen that the sheet 29 is A5 size and is accommodated vertically.

In the above embodiment, the micro switch 35 is used as the timing information detecting means, but the convex portion 3
A reflective or transmissive photosensor can be used by changing the shapes of 4a to 34e. Also,
As the size information detecting means, the photo sensors 36 and 37 are used.
Alternatively, a transmissive photosensor with an actuator may be used.

In the above embodiment, the set position of the paper 29 is based on the center position of the cassette body 31 in the width direction,
The paper 2 is formed by the two width direction guide members 32 on both sides.
9 is a so-called center resist type in which the width direction is restricted, but a so-called side resist type is also used in which the width direction is restricted by one width direction guide member 32 on the basis of one side (side). Good.

(Second Embodiment)

FIG. 8 shows the construction of the paper feed cassette 18 according to the second embodiment of the present invention. In this example,
A black-and-white pattern 50 is provided at equal intervals on the side surface of the cassette body 31 as an insertion speed information detection means, and a reflection type photosensor 51 is provided as an insertion speed information detection means on the printer body side facing the pattern 50. It is arranged.

In this embodiment, when the paper feed cassette 18 is inserted into the printer body, the output of the photo sensor 51 changes due to the black and white change of the pattern 50. The insertion speed of the paper feed cassette 18 is obtained from the interval between the black and white patterns 50 and the output of the photo sensor 51, and the width of the paper 29 is calculated from this insertion speed and the time when the output of the photo sensor 36 changes at both ends of the paper 29. (Size in the insertion direction B) can be obtained. FIG. 9 shows a timing chart at this time. The above processing is performed by the CPU 40 described above.

In this embodiment, the structure and operation of the photo sensor 37 are the same as those in the first embodiment, and the description thereof will be omitted.

(Third Embodiment)

10 and 11 show the construction of the paper feed cassette 18 according to the third embodiment of the present invention.
In this embodiment, the photosensors 52 and 53 as size information detecting means are arranged on the lower side of the cassette body 31 so as to face the bottom surface, and the bottom of the cassette body 31 is opposed to the photosensor 52 so as to face the photosensor 52. A plurality of sets of detection holes 54a to 54e as one detection hole are provided, and a detection hole 55 as a second detection hole is provided facing the photosensor 53. Multiple sets of detection holes 54a-5
4e is formed corresponding to each size of the paper 29.

In this embodiment, when the paper feed cassette 18 is inserted into the printer body, the output of the photosensor 52 is the paper 2
9 and the output of the photo sensor 53 changes according to the orientation of the paper 29.

FIG. 12 shows an example of A3 size paper 29.
This shows the state when the sheet is stored in this case. In this case, since all the detection holes 54a to 54e and the detection holes 55 are closed, the photo sensor 52, Both 53 remain off.

FIG. 13 shows a state in which the A4 size sheet 29 is accommodated sideways. In this case, all the detection holes 54a to 54e are closed, but the detection holes 55 are not closed. .. Therefore, the photo sensor 52 is off but the photo sensor 53 is on from the start to the end of the insertion of the paper feed cassette 18.

FIG. 14 shows a state in which the A5 size paper 29 is accommodated in the vertical direction. In this case, the innermost detection hole 54e is closed, but the other detection holes 54a to 54a. 54d and the detection hole 55 are not blocked. Therefore, the photo sensor 52 is turned on at the position corresponding to the detection holes 54a to 54d and the photo sensor 53 is also turned on from the start of the insertion of the paper feed cassette 18 to the end of the insertion.

In the paper size detecting apparatus of this embodiment, only two photosensors 52 and 53 are required as sensors.
Compared with the first and second embodiments, the number of sensors is reduced by two and the configuration is simpler.

When the paper feed cassette 18 containing no paper 29 is inserted, the photo sensors 52, 5
3 detects the detection holes 54a to 54e and the detection hole 55, respectively, and is turned on. Therefore, in this embodiment, it is possible to detect a state in which the sheet 29 is not stored.

In the first to third embodiments described above, the sensor as the size information detecting means is provided on the printer body side.
It is possible to easily detect the size of the paper 29 with the configuration in which only four sheets are provided. That is, since it is not necessary to attach a special component to the cassette body 31 side, the structure is simplified and an inexpensive paper size detection device can be realized.

Further, it is not necessary to specially move the sheet to the sheet feeding cassette side like the conventional detected material, and the sheet size is automatically changed only by inserting the sheet feeding cassette 18 into the printer body. Since it can be detected, operation mistakes can be eliminated and accurate detection can be performed.

The present invention has been described with reference to the examples.
The present invention is not limited to the above embodiments, but can be variously modified without departing from the scope of the invention. For example, in the above embodiment, an example in which the paper size detecting device of the present invention is applied to a paper feeding device of a laser beam printer has been described, but it goes without saying that it can also be applied to other copying machines, facsimiles and the like.

[0054]

As described above, according to the sheet size detecting apparatus of the first to fourth aspects, the sheet size is detected when the sheet cassette is inserted into the main body of the image forming apparatus. Thus, it is possible to realize an inexpensive paper size detection device that can accurately detect the paper size.

[Brief description of drawings]

FIG. 1 is a perspective view illustrating a configuration of a paper size detection device according to a first exemplary embodiment of the present invention.

FIG. 2 is a perspective view showing a convex portion taken out in the paper size detection device of FIG.

FIG. 3 is a diagram for explaining a paper size in the paper size detection device of FIG. 1 and a positional relationship between each convex portion and a sensor.

FIG. 4 is a block diagram showing a circuit configuration of a control unit of a laser beam printer using the paper size detection device of FIG.

5 is a timing chart for explaining an A3 size sheet detection operation in the sheet size detection apparatus of FIG. 1. FIG.

6 is a timing chart for explaining the detection operation when the A4 size sheet is accommodated in the sheet size detecting apparatus of FIG.

FIG. 7 is a timing chart for explaining a detection operation when the A5 size sheet is accommodated vertically in the sheet size detecting apparatus of FIG.

FIG. 8 is a perspective view illustrating a configuration of a paper size detection device according to a second exemplary embodiment of the present invention.

9 is a timing chart for explaining a detection operation of the paper size detection device of FIG.

FIG. 10 is a perspective view illustrating a configuration of a paper size detection device according to a third exemplary embodiment of the present invention.

FIG. 11 is a diagram for explaining the positional relationship between the paper size and the sensor and the detection hole of the paper size detection device of FIG.

FIG. 12 is a view illustrating A3 in the paper size detection device of FIG.
7 is a timing chart for explaining a detection operation when a size of paper is stored.

FIG. 13 is an A4 in the paper size detection device of FIG.
6 is a timing chart for explaining a detection operation when a size of paper is accommodated in a lateral direction.

FIG. 14 is an A5 in the paper size detection device of FIG.
6 is a timing chart for explaining a detection operation when a size of paper is accommodated vertically.

FIG. 15 is a vertical sectional view showing a schematic configuration of a laser beam printer using the paper size detection device of FIG.

[Explanation of symbols]

18 ... Paper feeding cassette, 29 ... Paper, 30a-30c ... Size sensor, 31 ... Cassette body, 32 ... Width direction guide member, 33 ... Paper feeding direction guide member, 34a-34e ... Convex part, 35 ... Micro switch, 36 , 37, 51, 5
2, 53 ... Photo sensor, 40 ... CPU, 50 ... Monochrome pattern, 54 ... Detection hole (first detection hole), 55 ... Detection hole (second detection hole)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication H04N 1/00 108 C 4226-5C H 4226-5C (72) Inventor Michiaki Yoshihara Iwatsuki City, Saitama Prefecture 3-7-1 Fuji Zerox Co., Ltd. Iwatsuki Plant (72) Inventor Tomio Fukao 3-7-1, Fuuchi, Iwatsuki City, Saitama Prefecture Fuji Zerox Co., Ltd. Iwatsuki Plant (72) Inventor Naoto Sugimura Saitama Prefecture Iwatsuki City, 3-7-1, Iwatsuki Plant, Fuji Zerox Co., Ltd. (72) Inventor, Toshinori Sasaki 3-7-1, Iwatsuki City, Iwatsuki City, Saitama Prefecture (72) Inventor, Kenji Hara 3-7-1, Fuchu, Iwatsuki City, Saitama Prefecture Fuji Zerox Co., Ltd. Iwatsuki Plant

Claims (4)

[Claims] 1. A paper size detection device for detecting the size of a paper housed in a paper feed cassette detachably provided in an image forming apparatus main body, the paper size detection device being provided in the paper feed cassette and the paper feed cassette. Timing information detected means that represents timing information when the image forming apparatus body is inserted into the image forming apparatus body; timing information detecting means that is provided on the image forming apparatus body side and detects the timing information; And a size information detecting means for detecting size information of the sheet in the insertion direction based on the timing information, and a size detecting means for detecting the size of the sheet based on the size information. Paper size detector. 2. A paper size detection device for detecting the size of paper stored in a paper feed cassette detachably provided in the image forming apparatus main body, the paper size detection device being provided in the paper feed cassette and the paper feed cassette. Timing information detected means that represents timing information when the image forming apparatus body is inserted into the image forming apparatus body; timing information detecting means that is provided on the image forming apparatus body side and detects the timing information; A first size information detecting unit that is provided on the side of the image forming apparatus and that detects the size information of the sheet in the insertion direction based on the timing information; Second size information detecting means for detecting size information in a direction orthogonal to the insertion direction; Sheet size detecting apparatus characterized by comprising a size detecting means for detecting the size of the paper on the basis of the information and the second size information. 3. A paper size detection device for detecting the size of paper stored in a paper feed cassette detachably provided in the main body of the image forming apparatus, the paper size detection device being provided in the paper feed cassette and the paper feed cassette. Insertion speed information detection means for indicating insertion speed information into the image forming apparatus main body, insertion speed information detecting means provided on the image forming apparatus main body side for detecting the insertion speed information, and the image forming apparatus Paper edge detection means provided on the main body side for detecting both edges of the paper along the insertion direction, and insertion of the paper based on the time required for output change of the paper edge detection means and the insertion speed information. A sheet size detecting device, comprising: a size detecting unit for detecting a size in a direction. 4. A paper size detection device for detecting the size of a paper housed in a paper feed cassette detachably provided in the main body of the image forming apparatus, the paper size detection device being provided in the paper feed cassette and feeding the paper. A plurality of sets of first detection holes that represent size information in the insertion direction of the paper cassette into the image forming apparatus main body, and size information in a direction orthogonal to the insertion direction of the paper, which is provided in the paper feed cassette. A second detection hole that represents the first detection hole and a first detection hole that is provided on the image forming apparatus body side and that detects the first detection hole to detect the first size information.
And a second size information detecting unit that is provided on the image forming apparatus main body side and that detects the second size information by detecting the second detection hole.
And a size detecting means for detecting the size of the paper based on the first size information and the second size information.