JP3450468B2 - Device for detecting size type of transported object and image forming apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conveyed body conveyed along a conveyed body conveying path for selectively conveying conveyed bodies of a plurality of sizes having different sizes in the width direction orthogonal to the conveying direction. The present invention relates to an apparatus for detecting a body size species and an image forming apparatus including the transported body size species detection apparatus as a transport recording medium size species detection apparatus.

[0002]

2. Description of the Related Art For example, in an image forming apparatus such as a copying machine or a printer, electrophotographic process, electrostatic recording process,
As a heat fixing means for fixing an unfixed toner image formed and carried on a recording medium such as a transfer paper or a photosensitive paper by an image forming means such as a magnetic recording process by a transfer method or a direct method, a heat roller method or a heat roller method is used. A film heating type device is generally used.

The heat roller system has a heat roller having a built-in heater and a pressure roller brought into pressure contact with the heat roller. The roller pair is rotated to pass a recording medium through a pressure contact nip portion of the rollers. By using paper, the unfixed toner image on the surface of the recording medium is thermally fixed by the heat of the heat roller.

In the film heating system, a recording medium is pressed against a fixed heater by a pressure roller through a heat resistant film, and the recording medium is passed through the pressure nip portion between the heater and the pressure roller together with the film. Thus, the heat of the heater is applied to the recording medium via the film to thermally fix the unfixed toner image on the surface of the recording medium, and the recording medium is separated from the film after passing through the pressure nip portion between the heater and the pressure roller. .

Recording media of various sizes are used in the image forming apparatus, and the dimension in the width direction orthogonal to the conveying direction is the maximum sheet passing width of the heat fixing means (= heat of the heat roller type heat fixing means). The effective maximum heating length of the roller, the effective maximum heating length of the heater of the film heating type heat fixing means) is smaller than the recording medium of the small size type, especially when the recording medium of the small size type is used. When continuously used, the heat roller portion or the heat roller portion corresponding to the non-sheet passing portion where the recording medium does not pass, which is the difference area between the maximum sheet passing width of the heat fixing means and the recording medium width dimension, is used. The temperature of the heater portion becomes significantly higher than the temperature of the heat roller portion or the heater portion corresponding to the paper passing portion because the heat of the portion is not consumed for heating the recording medium, so-called "non-paper passing portion temperature rising phenomenon". To generate heat to the heat roller and heater. When scratches occur and the temperature of the non-sheet passing area rises, when the next wide paper of a large size is passed through to fix the image, the temperature of the non-sheet passing area rises. A so-called "high temperature offset" of the toner image may occur in a portion corresponding to the portion.

As a means for avoiding this, a means for detecting the size species of the recording medium used in the apparatus (a plurality of size species having different sizes in the width direction orthogonal to the conveying direction) is provided. The means for changing the heat fixing condition and the recording medium based on the detection result have been taken.

FIG. 11 shows a conventional example of a means for detecting the size type of a recording medium used for paper passing through the apparatus.

Reference numeral A denotes a recording medium conveying path including the recording medium conveying roller pair 4a and 4b. In the case of this example, the conveying path A has two kinds of sizes, that is, a small size recording medium S1 and a large size recording medium S2. The recording medium is selectively transported by the central transport reference O-O. A1 is the conveyance width region of the small size recording medium S1 in the recording medium conveyance path A, and A2 is the large size recording medium S.
2 is a conveyance width area, and B is a difference area between the conveyance width areas A1 and A2 of the small size recording medium S1 and the large size recording medium S2.

101 and 102 are the first and second two, respectively.
A first means 10 which is a set of recording medium size type detecting means.
Reference numeral 1 is provided at a position within the carrying width area A1 of the small size recording medium S1, and second means 102 is provided at a position within the difference area B between the carrying width areas A1 and A2.

The first and second recording medium size type detecting means 101 and 102 are both displacing means 101a and 102a which are displaced by contact with the conveyed recording medium and detecting means 101b and 102b which detect displacement of the displacing means. In the case of this example, the displacement means 101a and 102a are swingers having an upper arm portion and a lower arm portion that are rotatable about the support shafts 101c and 102c, respectively.
102b is a photo interrupter. Oscillator 101a
In the free state, each of the 102a is held in a substantially vertical posture by gravity.

[0011]. When the recording medium passed through the conveyance path A is the small size recording medium S1, the first recording medium size type detecting means 10 is provided on the front side of the conveying recording medium S1.
1, the upper arm of the oscillating member 101a interferes and is kicked to come into contact with the lower surface of the conveyed recording medium.
Rotational displacement is made counterclockwise in the drawing around c, and the rotational displacement posture of the oscillator 101a is the recording medium S1.
It is held until it has passed the position of a. This rocker 1
The rotational displacement of 01a is detected when the optical path of the photoelectric section of the photo interrupter 101b is closed by the rotation of the lower arm of the oscillator 101a, and the output signal of the photo interrupter 101b changes from open to closed.

On the other hand, the second recording medium size type detecting means 1
The position of the oscillator 102a of No. 02 is small size recording medium S
Since it is outside the conveyance width area A1 of No. 1, there is no kicking due to the conveyance recording medium S1, and the output signal of the photo interrupter 101b remains in the open signal state.

The change from the open state to the closed state of the output signal of the photo interrupter 101b of the first recording medium size type detecting means 101 after the recording medium is passed, and the second recording medium size type detection Based on the open state of the output signal of the photo interrupter 102b of the means 102, a control circuit (not shown) detects and determines that the recording medium passed is the recording medium S1 of a small size type.

.. When the recording medium passed through the conveyance path A is the large size recording medium S2, the oscillating element 101a of the first and second recording medium size type detecting means 101, 102
Since the position of each of 102a is within the conveyance width area A2 of the large size recording medium S2, both rockers 101a
102a is kicked by the transport recording medium S2, and the output signals of the photo interrupters 101b and 102b of the first and second recording medium size species detecting means 101 and 102 change from the open state to the closed state. As a result, the control circuit (not shown) detects and determines that the fed recording medium is the large-sized recording medium S2.

.. Even when there are three or more types of recording media used for paper passing through the apparatus, the above-mentioned first and second sizes are respectively provided in the difference areas between the transport width areas of the recording media of each size species.
By additionally adding a set of oscillators and photointerrupters similar to the recording medium size type detecting means 101 and 102, the recording medium of each size type is similarly detected.

[0016]

However, in such a structure, the means for detecting the size type of the recording medium as the conveyed object used as paper to be passed through the apparatus has such a structure that the oscillating member as the displacement means is provided for each size type. Since a combination device including a photo interrupter as the displacement detection means is required, there is a problem that the overall configuration becomes complicated and the cost increases.

The present invention solves this problem, and provides an apparatus for detecting the size type of the transported body of this type, and an image forming apparatus equipped with the apparatus as a size type detecting apparatus for the transport recording medium. The object of the invention is to simplify the structure of the means and reduce the cost.

[0018]

SUMMARY OF THE INVENTION The present invention is a size type detection device for an object to be conveyed and an image forming device characterized by the following configurations.

(1) The size type of the transferred object to be transferred through the transferred path of the transferred object for selectively transferring the transferred objects of a plurality of sizes of different sizes in the width direction orthogonal to the transfer direction A device for detecting, which is arranged in the conveyance width region of the conveyance target of the minimum size species, and in the difference region between the conveyance width regions of the conveyance target of each size species, Displacement occurs due to the contact between the transported object contactor that corresponds to each of the transported objects of each size type and the transported object of the corresponding size type of each transported object contact, and the displacement amount A single displacing means that is made different between body size types, and means for detecting the displacement amount of the displacing means and determining the size type of the transported object transported on the transported object transport path from the displacement amount. An apparatus for detecting a size of a transported object, comprising:

(2) The displacement amount of the displacement means associated with the contact of each transferred member contacting the transferred member of a corresponding size type changes stepwise. Carrier size type detection device.

(3) The means for selectively transporting a plurality of recording mediums of different sizes having different sizes in the width direction orthogonal to the transportation direction, and the size of the recording medium transported through the recording medium transport path are selected. An image forming apparatus having a detecting unit, wherein the recording medium size type detecting unit is a recording medium conveying path,
A recording medium contact corresponding to each of the plurality of size type recording media, which is arranged in the conveying width region of the minimum size type recording medium and in the difference region between the conveying width regions of each size type recording medium, respectively. And a single displacing means that is displaced in accordance with the contact between the recording medium and the recording medium of the corresponding size species of each recording medium contact, and the displacement amount is different between the size species of the recording medium, and the displacing means. An image forming apparatus having means for detecting the amount of displacement of the recording medium and determining the size type of the recording medium conveyed through the recording medium conveying path from the amount of displacement.

(4) The image forming apparatus according to (3), wherein the displacement amount of the displacement means changes stepwise with the contact of each recording medium contactor with a recording medium of a corresponding size type. .

(5) The conveyance recording medium detected by the recording medium size type detecting means has means for forming an image on the conveyed recording medium and heat fixing means for thermally fixing the formed image on the recording medium. The heat condition of the heat fixing means is controlled according to the size type (3) or (4).
The image forming apparatus according to item 1.

(6) A means for forming an image on the conveyed recording medium, and a heat fixing means for thermally fixing the formed image on the recording medium, wherein the conveyed recording medium detected by the recording medium size type detecting means The image forming apparatus according to (3) or (4), characterized in that the timing of conveying the recording medium is controlled according to the size type.

[0025]

That is, according to the present invention, the displacement means for detecting each size species of a plurality of size species of the transported object (recording medium) used for passing the paper through the apparatus. And the detection means for detecting the displacement of the displacement means need only use one set common to all size species. In the transport width area of the transported object of the minimum size species, and in the difference area between the transport width areas of the transported objects of each size species, the transported object contacts are respectively associated with the transported objects of each size species. Although provided, the configuration of the transferred body contactor can be made extremely simple. Therefore, this type of transported object size type detection device,
Also, with regard to an image forming apparatus equipped with the apparatus as a size type detection apparatus for a transport recording medium, the overall means configuration of the detection apparatus can be greatly simplified and the cost can be reduced significantly.

Further, by making it serve also as a means for detecting the size of the transported object, for example, a detection means for determining the registration of the recording medium as the transported object in the image forming apparatus, it becomes more effective in terms of cost. can do.

[0027]

【Example】

<First Embodiment> (FIGS. 1 to 5) (1) Example of Image Forming Apparatus (FIG. 1) FIG. 1 is equipped with a conveyed object size species detection apparatus according to the present invention as a conveyance recording medium size species detection apparatus. FIG. 3 is a schematic configuration diagram of an example of an image forming apparatus. The image forming apparatus of this example is a laser beam printer using a transfer type electrophotographic process.

Reference numeral 3 is a manual paper feed table for a recording medium (transfer paper) S, and 2 is a movable paper side guide provided on the paper feed table, and the recording medium S inserted into the apparatus from the paper feed table is provided therein. It functions to shift to the center in the width direction and regulate it to the center transport standard.

The recording medium S inserted into the apparatus from the paper feed table 3 is detected in the apparatus by a detection means (not shown), and then the paper feed roller 1 is rotationally driven at a predetermined control time to cause the inside of the apparatus. To the transport roller pair 4a and 4b
The sheet is nipped and conveyed at a predetermined timing, and is introduced at a predetermined timing into a transfer portion N which is a pressure contact nip portion between the rotary photosensitive drum 7 and the transfer roller 8 to obtain desired image information formed and carried on the outer peripheral surface of the rotary photosensitive drum 7. It receives the transfer of the corresponding toner image.

Reference numeral 20 denotes a pair of conveying rollers 4a and 4b and a transfer portion N.
The recording medium size type detecting means is disposed in the recording medium conveying path between the recording medium and the recording medium, which will be described in detail later in (2).

The recording medium to which the toner image has been transferred at the transfer portion N is separated from the surface of the rotary photosensitive drum 7 and introduced into the heat fixing means 15 to undergo the heat fixing process of the unfixed toner image, and the intermediate conveying roller pair. In the case of this example, the sheet is discharged from the pair of sheet discharge rollers 17a and 17b onto the sheet discharge tray 18 through 16a and 16b in a face-down mode with the image surface facing downward.

Reference numeral 12 denotes a laser scanner which outputs a modulated laser beam corresponding to a time-series electric digital pixel signal of target image information input from a host device such as a computer or an image reading device (not shown). Then, the surface of the rotary drum 7 is scanned and exposed through the folding mirror 13.

Reference numeral 11 denotes a charging roller for uniformly charging the surface of the rotating photosensitive drum 7 to a predetermined polarity and potential. The laser light is applied to the surface of the rotating photosensitive drum 7 uniformly charged by the charging roller 11. By performing scanning exposure, an electrostatic latent image corresponding to target image information is formed on the surface of the rotary photosensitive drum 7.

The electrostatic latent image is the developing roller 9 of the developing device 10.
Is visualized as a toner image, and the toner image is transferred to the recording medium S at the above-mentioned transfer portion N.

After the toner image is transferred onto the recording medium, the surface of the rotary photoreceptor 7 is cleaned by a cleaning device 14 to remove residual contaminants such as transfer residual toner, and is repeatedly used for image formation.

In the apparatus of this example, the four process devices of the photosensitive drum 7, the charging roller 11, the developing device 10 and the cleaning device 14 are made into a process cartridge, and the opening / closing cover plate 1 of the device is used.
9 is opened so that they can be attached and removed collectively.

The heat fixing means 15 of this example is of a film heating type, 15a is a heater frame, and 15b is a heater frame.
Is a heater held on the lower surface of this heater frame, 15
Reference numeral c is a cylindrical heat-resistant film loosely fitted to the heater frame 15a including the heater 15b, and reference numeral 15d is a pressure roller that is pressed against the lower surface of the heater 15b with the film 15c interposed therebetween.

When the pressure roller 15d is rotationally driven in the recording medium conveying direction, the cylindrical heat-resistant film 15c is driven to rotate around the outer periphery of the heater frame 15a while the inner surface side of the cylindrical heat-resistant film 15c closely slides on the lower surface of the heater 15b.

The recording medium S having the transferred toner image is introduced between the film 15c at the pressure contact portion and the pressure roller 15d in the upward direction of the image surface, whereby the heat of the heater 15b is recorded through the film 15c. The toner image applied to the medium is thermally fixed.

(2) Recording Medium Size Type Detecting Means 20 (FIGS. 2 to 5) FIG. 2 is a perspective view of this detecting means 20 and FIG. 3 is a side view. A is a recording medium conveying path including the recording medium conveying roller pairs 4a and 4b. In the case of this example, as in the case of FIG. 11 described above, the conveying path A connects the small size recording medium S1 and the large size recording medium S2. It is assumed that recording media of two types of sizes are selectively conveyed by the center conveyance reference OO. A1 is a conveyance width region of the small size recording medium S1 in the recording medium conveyance path A, A2 is a conveyance width region of the large size recording medium S2, B is a conveyance width region of the small size recording medium S1 and the large size recording medium S2. This is the difference area between A2.

Reference numeral 5d denotes a single horizontal axis arranged in a direction orthogonal to the recording medium conveyance direction of the conveyance path A, and bearings 5e and 5e.
It is arranged so that it can rotate freely and is prevented from moving in the thrust direction.

Reference numerals 5a and 5b are first and second recording medium contacts which are integrally fixed to the horizontal axis 15d at intervals. The first recording medium contactor 5a is located at a position within the carrying width area A1 of the small-sized recording medium S1, and the second recording medium 5b is located at the difference area B between the carrying width areas A1 and A2.
It is arranged corresponding to each position inside.

Reference numeral 5c is a light-shielding plate as a displacement means, which is integrally fixed to the end of the horizontal axis 5d on the opposite side of the first recording medium contactor 5a. Reference numeral 6 is a photo interrupter as a displacement detecting means of the light shielding plate 5c.

The first and second recording medium contacts 5a and 5b,
The horizontal axis 5d to which the light-shielding plate 5c is fixed is shown in FIG. 3 by the balance of the members 5a, 5b, 5c against the gravity of the three members at all times, or by a rotation biasing spring and a stopper (not shown) of a weak biasing force. It is kept in such a rotation angle posture state. In this state, the second recording medium contactor 5b
Is in a substantially vertical upward rotation angle posture, and the first recording medium contactor 5a is in a diagonal upward rotation angle posture inclined to the downstream side in the recording medium transport direction to some extent from the substantially vertical upward posture,
The light shielding plate 5c is provided with an angle phase difference between the three members 5a, 5b, 5c so that the light shielding plate 5c is in an oblique downward rotation angle posture which is inclined to the downstream side in the recording medium transport direction to a certain degree rather than the substantially vertical downward posture. .

.. Thus, when the recording medium passed through the conveyance path A is the small-sized recording medium S1, the first contact 5a interferes with the front side of the conveyance recording medium S1 and is kicked to move the horizontal axis 5d. Transport recording medium S while rotating counterclockwise
As shown in FIG. 4, the recording medium S1 comes into contact with the lower surface of the recording medium S1 and has a lateral rotation angle posture facing the downstream side in the recording medium conveyance direction. Will be held until the end.

Since the position of the second recording medium contactor 5b is outside the carrying width area A1 of the small size recording medium S1, it does not interfere with the small size recording medium S1.

The horizontal rotation of the first contact 5a causes the horizontal shaft 5d to rotate counterclockwise, whereby the second contact 5b is rotated.
The light-shielding plate 5c is also rotationally displaced in the counterclockwise direction, and the light-shielding plate 5c assumes a substantially vertical downward rotation angle posture as shown in FIG. 4 to close the optical path of the photoelectric section 6a of the photo interrupter 6, thereby The output signal of the photo interrupter 6 changes from the open signal state (FIG. 3) to the closed signal state (FIG. 4),
In this optical path closed state, the recording medium S1 has the first contactor 5a.
Passes through the position and continues until the end.

From the signal change of the output signal of the photo interrupter 6 in one step from open to closed, it is detected by a control circuit (not shown) that the recording medium passed through the apparatus is the recording medium S1 of a small size type.・ It will be judged.

After that, when the transport recording medium S1 has finished passing the position of the first contactor 5a, the horizontal axis 5d and the first and second contactors 5a and 5b and the light shielding plate 5c which are integral with the horizontal axis 5d.
Becomes a free state, rotates back, and automatically returns to the initial standby rotation angle state of FIG.

.. When the recording medium passed through the conveyance path A is the large size recording medium S2, the conveyance recording medium S2
On the front side of the second contact 5b, the second contact 5b interferes with the first contact 5a and is kicked to rotate the horizontal shaft 5d in the counterclockwise direction to contact the lower surface of the transport recording medium S2, As shown in FIG. 5, the recording medium has a lateral rotation angle posture facing the downstream side in the recording medium conveyance direction, and the rotation angle posture is held until the recording medium S2 has passed the position of the second contact 5b. .

The rotation of the horizontal shaft 5d by the lateral rotation of the second contact 5b causes the first contact 5a and the light shielding plate 5c to rotate.
Is also rotated counterclockwise, and the light shielding plate 5c is in a substantially vertical downward rotation angle posture, and the optical path of the photoelectric section 6a of the photointerrupter 6 is once closed, and further counterclockwise rotation causes the photoshield 6a to rotate. After passing through the photoelectric section 6a of the interrupter 6, the photointerrupter 6 is pivoted to a position opposite to the initial standby rotation angle position, as shown in FIG.

As a result, the output signal of the photo interrupter 6 temporarily changes from the open signal state (FIG. 3) to the closed signal state (FIG. 4), and immediately changes to the open signal state (FIG. 5). From this two-step signal change of open → close → open, the control circuit detects / determines that the recording medium passed through the apparatus is the large-sized recording medium S2.

When the transport recording medium S2 has finished passing the position of the second contact 5b, the horizontal axis 5d and the first and second contacts 5a and 5b and the light shielding plate 5c which are integral with the horizontal axis 5d are free. Then, it returns to the whole and rotates, and automatically returns to the initial standby rotation angle state of FIG.

The light shielding plate 5 as a displacement means by the contact between the first contact 5a and the transport recording medium S1.
c rotation angle displacement amount (FIG. 3 → FIG. 4) and rotation angle displacement amount of the light shielding plate 5c as displacement means (FIG. 3 → FIG. 4) due to contact between the second contact 5b and the transport recording medium S2. 5) is different from the former in that the latter is larger than the former so that the mounting angles of the first contact 5a and the second contact 5b with respect to the horizontal axis 5d are different from each other to provide a phase difference. There is.

The displacement means described in this embodiment can also be used as means for determining the registration of the recording medium.

As in the present embodiment, the type of size of the recording medium is detected, and the thermal fixing means 15 controls the thermal fixing conditions for fixing the toner image on the recording medium or the conveyance timing of the recording medium based on the detected size. As a result, the temperature rise in the non-sheet passing portion of the heat fixing unit 15 can be suppressed, and various problems due to the temperature rise in the non-sheet passing portion (roller material, damage, film twist, high temperature offset, etc.) can be prevented.

Here, as the control of the heat fixing condition, a method of providing a plurality of heaters in the axial direction and shortening the ON time when the heater at the end passes through a narrow recording medium can be considered. Further, as a method of controlling the conveyance timing of the recording medium, it can be implemented by increasing the conveyance time interval of the recording medium when the recording medium having a small width is conveyed.

<Second Embodiment> (FIGS. 6 to 10) In this embodiment, it is possible to detect the transport recording media S1, S2, and S3 of three sizes of small size, medium size, and large size. It is a thing.

FIG. 5 is a perspective view of the detecting means portion 20. In FIG. 5, the small-sized / medium-sized / large-sized recording mediums S1, S2, and S3 are respectively conveyed by the central reference OO. A1 is a conveyance width region of the small size recording medium S1 in the recording medium conveying path A, and A2 is a medium size recording medium S.
2 is the conveyance width area, A3 is the conveyance width area of the large size recording medium S3, and B is the small size recording medium S1 and the medium size recording medium S.
The difference area between the two conveyance width areas A1 and A2, C is the conveyance width area A2 of the medium size recording medium S2 and the large size recording medium S3.
This is the difference area between A3.

5d is the transport path A as in the first embodiment.
Is a single horizontal axis arranged so as to be freely rotatable by bearings 5e and 5e in the direction orthogonal to the recording medium conveyance direction and to prevent movement in the thrust direction.

Reference numerals 5a, 5b, and 5f denote first, second, and third recording medium contactors, which are integrally fixed to the horizontal axis 5d at intervals. The first contact 5a is located at a position within the carrying width area A1 of the small-sized recording medium S1, the second contact 5b is located at a position within the difference area B between the carrying width areas A1 and A2, and The contacts 5f are arranged corresponding to the positions in the difference area C between the conveyance width areas A2 and A3. Reference numeral 5c is a light-shielding plate as a displacing means which is integrally fixed to the end of the horizontal axis 5d on the opposite side of the first recording medium contactor 5a. Reference numeral 6 is a photo interrupter as a displacement detecting means of the light shielding plate 5c.

In the case of this example, the light-shielding plate 5c is provided with _{two first} and _second portions 5c ₁ and 5c ₂ which are spaced from each other by a light-shielding portion with respect to the optical path of the photoelectric portion of the photo interrupter 6.

FIG. 7 is a side view showing the standby rotation angle posture states of the first to third recording medium contacts 5a, 5b and 5f and the light shielding plate 5c in the free state.

.. Thus, when the recording medium passed through the conveyance path A is the small-sized recording medium S1, the first contact 5a interferes with the front side of the conveyance recording medium S1 and is kicked to move the horizontal axis 5d. Transport recording medium S while rotating counterclockwise
As shown in FIG. 8, when the recording medium S1 contacts the lower surface of the recording medium S1, the recording medium S1 is located at the position of the first contact 5a. Will be held until the end. As the horizontal shaft 5d rotates counterclockwise by the horizontal rotation of the first contactor 5a, as shown in FIG. 8, the first light shielding portion 5c ₁ of the light shielding plate 5c is the photoelectric portion of the photo interrupter 6. The rotation angle is such that the optical path of 6a is closed.

As a result, the output signal of the photo interrupter 6 changes from the open signal state (FIG. 7) to the closed signal state (FIG. 8), and this optical path closed state causes the recording medium S1 to move to the position of the first contact 5a. Will continue until the end.

From the signal change of the output signal of the photo interrupter 6 in one step from open to closed, it is detected by a control circuit (not shown) that the recording medium passed through the apparatus is the recording medium S1 of a small size type.・ It will be judged.

After that, when the conveyed recording medium S1 finishes passing the position of the first contactor 5a, the horizontal axis 5d and the first to third contactors 5a, 5b, 5f and the light shielding plate 5c which are integral with the horizontal axis 5d. Becomes a free state, rotates back, and automatically returns to the initial standby rotation angle state of FIG.

.. When the recording medium passed through the conveyance path A is the medium size recording medium S2, the conveyance recording medium S2
The second contact 5b interferes with and is kicked by the front side of the horizontal axis 5d.
While being rotated counterclockwise, the lower surface of the conveyed recording medium S2 is brought into contact with the recording medium S2 to have a lateral rotational angle posture facing the downstream side in the recording medium conveying direction as shown in FIG. The medium S2 is held until the medium S2 has passed the position of the second contact 5b and is finished. The light shielding plate 5 is rotated in the counterclockwise direction by rotating the horizontal shaft 5d by the above-described horizontal rotation of the second contact 5b.
As for c, as shown in FIG. 9, the gap opening between the first light-shielding portion 5c ₁ and the second light-shielding portion 5c ₂ is located at the light-path portion of the photoelectric section 6a of the photo interrupter 6 to open the light-path portion. Rotation angle.

As a result, the output signal of the photo interrupter 6 changes from the open signal state (FIG. 7) to the first light-shielding portion 5c ₁
Then, the optical path portion of the photoelectric section 6a is once shielded from light, so that the state changes to the closed signal state (FIG. 8), and immediately thereafter, the first shield portion 5c is immediately closed.
The gap opening between ₁ and the second light-shielding portion 5c ₂ is located in the optical path portion of the photoelectric section 6a and the optical path portion is opened, so that the state changes to the open signal state (FIG. 9). The optical path open state is maintained until the recording medium S1 passes the position of the second contact 5b and ends.

Based on the two-step signal change of the output signal of the photo interrupter 6 from open to closed to open, the control medium (not shown) indicates that the recording medium passed through the apparatus is the medium size recording medium S2. Is detected and judged by.

After that, when the transport recording medium S2 finishes passing the position of the second contactor 5b, the horizontal axis 5d and the first to third contactors 5a, 5b, 5f and the light shielding plate 5c which are integral with the horizontal axis 5d. Becomes a free state and returns to rotate, and then automatically returns to the first standby rotation angle state of FIG.

.. When the recording medium passed through the conveyance path A is the large size recording medium S3, the conveyance recording medium S3
The third contact 5f interferes with and is kicked by the front side of the horizontal axis 5d.
While contacting the lower surface of the transport recording medium S3 while rotating in a counterclockwise direction, as shown in FIG. 10, a horizontal swing angle posture facing the downstream side in the transport direction of the recording medium is obtained.
However, it is held until the recording medium S3 has passed the position of the third contact 5f. Shading member 5c in rotation in the counterclockwise direction of the horizontal axis 5d by the lateral rotation of the third contactor 5f, as in FIG. 10, the photoelectric section of the second light-shielding portion 5c ₂ is photo-interrupter 6 The rotation angle is such that it is located in the optical path portion 6a and the optical path portion is closed.

As a result, the output signal of the photo interrupter 6 changes from the open signal state (FIG. 7) to the first light-shielding portion 5c ₁
Then, the optical path portion of the photoelectric section 6a is once shielded from light, so that the state changes to the closed signal state (FIG. 8), and immediately thereafter, the first shield portion 5c is immediately closed.
The gap opening between ₁ and the second light-shielding portion 5c ₂ is located in the optical path portion of the photoelectric section 6a, and the optical path portion is opened, thereby changing to the open signal state (FIG. 9). Immediately after the second light-shielding portion 5c ₂ is located in the optical path portion of the photoelectric section 6a and the optical path portion is closed, the closed signal state (FIG. 10)
, And this optical path closed state is maintained until the recording medium S3 passes the position of the third contact 5f and ends.

It is not shown that the recording medium passed through the apparatus is a large-sized recording medium S3 from the three-step signal change of the output signal of the photo interrupter 6 from open → close → open → close. It is detected and judged by the control circuit.

After that, when the transport recording medium S3 finishes passing the position of the third contactor 5f, the horizontal axis 5d and the first to third contactors 5a, 5b, 5f and the light shielding plate 5c which are integral with the horizontal axis 5d. Becomes a free state and returns to rotate, and then automatically returns to the first standby rotation angle state of FIG.

The light-shielding plate 5 as a displacing means by the contact between the first contact 5a and the transport recording medium S1.
c rotation angle displacement amount (FIG. 7 → FIG. 8) and rotation angle displacement amount of the light shielding plate 5c as displacement means by contact between the second contact 5b and the transport recording medium S2 (FIG. 7 → (Fig. 9)
So that the rotation angle displacement amount (FIG. 7 → FIG. 10) of the light shielding plate 5c serving as the displacement means due to the contact between the third contactor 5f and the transport recording medium S3 becomes larger in order. Horizontal axis 5d of the first to third contacts 5a, 5b, 5f
The mounting angle with respect to is different from each other to provide a phase difference.

As described above, in the case of this embodiment, the first embodiment
3 types of transport recording medium sizes, one more than in the case of
Can be detected and judged. Further recording medium
Increasing the number of contacts 5a, 5b, 5f, and also a light blocking plate
5c light-shielding portion 5c₁ ・ 5c ₂ The configuration that increases
It is also possible to detect and judge multiple sizes of 4 or more types.
Is.

Needless to say, the present invention can be applied to the one in which the recording medium is conveyed on the one-sided conveyance basis.

The present invention is not limited to the size type detection of the conveyed recording medium in the image forming apparatus, and can be widely used as the size type detection means of the conveyed object.

[0080]

As described above, according to the present invention, even if there are a plurality of size species of the transported object (recording medium) used for passing through the apparatus, it is possible to detect each size species. For this purpose, only one set of the displacement means and the detection means for detecting the displacement of the displacement means, which are common to all size species, may be used. In the transport width area of the transported object of the minimum size species, and in the difference area between the transport width areas of the transported objects of each size species, the transported object contacts are respectively associated with the transported objects of each size species. Although provided, the configuration of the transferred body contactor can be made extremely simple. Therefore, with respect to this type of size detection device for a conveyed object and an image forming apparatus equipped with this device as a size type detection device for a transport recording medium, the means configuration of the detection device is greatly simplified and the cost is reduced. can do.

Further, the size of the transported object detecting device, for example, the detection means for determining the registration of the recording medium as the transported object in the image forming apparatus, is more effective in terms of cost. can do.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment.

FIG. 2 is a perspective view of a size type detection unit portion of a conveyed recording medium.

FIG. 3 is a side view of the detection means portion (in a free state)

FIG. 4 is a state diagram of a detection unit portion when a recording medium of a small size type is conveyed.

FIG. 5 is a state diagram of a detection unit portion when a large-sized recording medium is conveyed.

FIG. 6 is a perspective view of a size type detection means portion of a conveyed recording medium according to a second embodiment.

FIG. 7 is a side view of the detecting means portion (in a free state).

FIG. 8 is a state diagram of a detection unit portion when a small-sized type recording medium is conveyed.

FIG. 9 is a state diagram of a detection unit portion when a medium-sized recording medium is conveyed.

FIG. 10 is a state diagram of a detection unit portion when a large-sized recording medium is conveyed.

FIG. 11 is a perspective view of a size type detection unit portion of a conventional transport recording medium.

[Explanation of symbols]

A recording medium transport path 0-O central transport reference line S (S1 to S3) recording medium of different size (transport target) 4a, 4b transport rollers A1, A2, A3 various size transport width areas B, C Difference areas 5a, 5b, 5f of conveyance width areas of size type First to third recording medium contactors 5c Light-shielding plate 6 as displacement means Photointerrupter as displacement detection means

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B65H 43/00 G03G 21/00 370

Claims (6)

(57) [Claims] 1. A size species of a transported body transported along a transported body transporting path for selectively transporting a plurality of transported species having different sizes in a width direction orthogonal to the transport direction is detected. And a plurality of the plurality of sizes of the plurality of size objects to be transferred, and a difference between the transfer width areas of the size objects to be transferred. The transported object contacts corresponding to the transported objects of each size type and the transferred objects contact the transported objects of the corresponding size type and are displaced, and the displacement amount is And a means for detecting the amount of displacement of the displacement means and determining the size type of the transported object transported on the transported path of the transported object from the displacement amount. A transported object size type detection device characterized by the above. 2. The transferred object according to claim 1, wherein the displacement amount of the displacement means accompanying the contact of each transferred object contactor with the transferred object of a corresponding size type changes stepwise. Body size species detection device. 3. A means for selectively transporting a plurality of sizes of recording medium having different sizes in the width direction orthogonal to the transport direction, and a size species of the recording medium transported through the recording medium transport path. The recording medium size type detecting means is a recording medium size species detecting means, wherein the recording medium size species detecting means is in the conveyance width area of the recording medium of the minimum size species and between the conveyance width areas of the recording medium of each size species. The recording medium contacts, which are respectively disposed in the difference areas, respectively correspond to the plurality of recording media of each size type, and the recording medium contacts are displaced along with the contact of the recording media of the corresponding size type. , Only one displacing means whose displacement amount is different between the size types of the recording medium, and the displacement amount of the displacing means are detected, and the size type of the recording medium conveyed on the recording medium conveying path is determined from the displacement amount. To have the means to judge An image forming apparatus symptoms. 4. The image forming apparatus according to claim 3, wherein the displacement amount of the displacement means accompanying the contact of each recording medium contactor with a recording medium of a corresponding size type is changed stepwise. 5. The size of the conveyed recording medium, which has means for forming an image on the conveyed recording medium and thermal fixing means for thermally fixing the formed image on the recording medium, and which is detected by the recording medium size type detecting means. The image forming apparatus according to claim 3 or 4, wherein the heat condition of the heat fixing unit is controlled according to the type. 6. The size of the conveyed recording medium, which has means for forming an image on the conveyed recording medium and thermal fixing means for thermally fixing the formed image on the recording medium, and which is detected by the recording medium size type detecting means. 5. The image forming apparatus according to claim 3, wherein the timing of conveying the recording medium is controlled according to the type.