JP2809654B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile, and more particularly, to an image forming apparatus in which a sheet stacking device is added to a sheet discharge unit.

(B) Conventional technology Conventionally, generally, image forming apparatuses such as a copying machine, a printer, and a facsimile have a paper discharge tray for storing a discharge sheet.

As an example of the above-described image forming apparatus, a laser beam printer M 'has an apparatus main body 1 and an image forming section including a photosensitive drum 2 and the like in a substantially central portion of the apparatus main body 1 as shown in FIG. 3 is provided. In the image forming unit 3, a corona charger 5, a developing unit 6, a transfer charger 7 and a cleaning unit 9 are arranged around the photosensitive drum 2, and a reflection mirror 10 is provided adjacent to the image forming unit 3. And an optical system 12 including a scanner 11 and the like. Also,
A paper feed unit 13 is provided on one side (right side in the figure) of the apparatus main body 1, and a cassette 15 for accommodating a large number of sheets P is detachably mounted on the paper feed unit 13. It has become. Further, a paper feed roller 16 is arranged so as to face the cassette 15 mounted on the paper supply unit 13, and a registration roller pair 17 is arranged adjacent to the photosensitive drum 2,
The sheets P in the cassette 15 are fed to the image forming unit 3 one by one in synchronization with the rotation of the photosensitive drum 2. A transport guide 19 is provided downstream of the photosensitive drum 2, and a fixing device 20 is disposed downstream of the transport guide 19.

On the other hand, a paper discharge unit 21 is provided on the other side (left side in the figure) of the apparatus main body 1, and an upper paper discharge tray 22 is arranged on the paper discharge unit 21 so as to be located above the apparatus main body 1. Along with
A foldable side discharge tray 23 is arranged on the side of the apparatus main body 1 so as to be openable and closable. The discharge unit 21 is provided with a pair of transport rollers 25 facing the fixing device 20. Further, a curved transport path 26 is formed from the pair of transport rollers 25 to the upper discharge tray 22. And the curved conveyance path 26
A paper discharge roller 27 is arranged at the downstream end of the printer. A discharge flapper 29 is disposed in the vicinity of the pair of conveyance rollers 25, and the conveyance direction of the sheet P discharged from the fixing device 20 is directed to the upper discharge tray 22 side or the side discharge tray 23 side. It is designed to switch.

In the laser beam printer M ', optical information is exposed on the photosensitive drum 2 by the scanner 11 according to an external signal, and an electrostatic latent image is formed on the photosensitive drum 2. Further, the electrostatic latent image on the photosensitive drum 2 is developed by the developing device 6 to become a toner image, and the toner image is transferred from the paper supply unit 13 to the sheet P conveyed in synchronization with the photosensitive drum 2. The sheet P to which the toner image has been transferred is separated from the photosensitive drum 2 and conveyed to a fixing device 20 via a conveyance guide 19, where the toner image is fixed by the fixing device 20, and a conveying roller pair 25 is fixed.
Sent to

When the sheet P is to be discharged to the side discharge tray 23, the side discharge tray 23 is rotated from an upright position along the side of the apparatus main body 1 to a substantially horizontal position, and the conveyance roller pair The sheet P sandwiched between the sheets 25 is guided by the sheet discharge flapper 29 switched to the side sheet discharge tray 23 side, passes through the sheet discharge holes 30, and faces the side sheet discharge tray 23 with the image side up. The paper is discharged in the up state.

When the sheet P is discharged to the upper discharge tray 22, the sheet P nipped by the pair of conveying rollers 25 is guided by the discharge flapper 29 switched to the upper discharge tray 22 side to be curved and conveyed. The sheet is conveyed along the path 26, is turned upside down, and is discharged from the discharge roller 27 onto the upper discharge tray 22 in a face-down state with the image side down.

(C) Problems to be Solved by the Invention By the way, when the above-mentioned laser beam printer M ′ discharges a sheet onto the upper discharge tray 22, for example, the sheets are sequentially discharged onto the upper discharge tray 22. , Discharge roller
When the sheet is stacked up to the 27 sheet discharge port 27a, no more sheets can be stacked.If the sheet is still discharged, the discharged sheet hits the already stacked sheet and jams, or the sheet falls off the tray 22. There are drawbacks such as inconveniences. In order to avoid such a problem, when the height of the sheets stacked on the tray 22 reaches a certain level, it is necessary to remove the sheets.

Therefore, the present invention provides a configuration in which when the discharge tray is full, a sheet is discharged to a sheet stacking device having additional sheets,
It is an object of the present invention to solve the above-mentioned problems.

(D) Means for Solving the Problems The present invention has been made in view of the above circumstances,
A sheet discharge unit having a discharge tray for storing discharge sheets, and a sheet stacking device mounted on the sheet discharge unit, wherein the sheet stacking device is an additional discharge sheet for storing the discharge sheets. A tray and full detection means for detecting that the discharge tray is full, wherein the discharge direction of the discharge sheet is switched to the additional discharge tray side based on the full detection of the full detection means. .

The sheet stacking apparatus may further include a switching unit configured to switch a discharge direction of the discharge sheet to the additional discharge tray based on the full state detection of the full state detection unit.

Further, the sheet stacking device has a second full detecting means for detecting the fullness of the additional discharge tray at a position facing the additional discharge tray, and an image based on the full detection by the second full detecting means. It is characterized by comprising stopping means for controlling so as to stop the forming operation.

(E) Operation Based on the above configuration, when the discharge tray becomes full, the full discharge detecting means provided in the additional discharge tray detects that the discharge tray is full, and the discharge direction of the sheet is increased. Switch to tray side.

(F) Example Hereinafter, examples of the present invention will be described with reference to the drawings.

The same parts as those of the laser beam printer M 'are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 1, the laser beam printer M1 according to the present embodiment includes the above-described conventional laser beam printer M '.
Similarly, a paper discharge unit 21 is provided on the side of the apparatus body 1 (left side in the figure), and an upper paper discharge tray 22 is arranged in the paper discharge unit 21.

Further, an expandable sheet stacking device 31 is removably disposed above the sheet discharge section 21. The sheet stacking device 31 includes an additional sheet discharge tray 32 for storing discharged sheets. The sheet stacking device 31 has an additional transport path 33 for guiding and transporting the discharged sheet to the additional paper discharge tray 32.
The upstream portion of the additional transport path 33 is connected to the above-described curved transport path 26, and the downstream portion of the additional transport path 33 opens toward the additional paper discharge tray 32. Then, the additional transport path 33
An additional discharge roller pair 35 is disposed in the vicinity of the downstream portion of the printer, and discharges a discharge sheet conveyed through the additional conveyance path 33 to the additional discharge tray 32.

As shown in detail in FIG. 2, an additional flapper 36 is disposed near the upstream portion of the additional transfer path 33, and a solenoid 37 is connected to the flapper 36. When the sheet stacking device 31 is mounted above the paper discharge unit 21 of the apparatus main body 1, the sheet stacking device 31 is located at a connection portion between the additional transport path 33 and the curved transport path 26, and is displaced by turning on / off a solenoid 37. Then, the conveyance direction of the discharged sheet conveyed through the curved conveyance path 26 is switched to the upper discharge tray 22 side or the additional discharge tray 32 side.

In addition, a detection lever 39 and a full sensor are provided below the additional paper discharge tray 32 so as to face the upper paper discharge tray 22.
A full detector 41 for detecting the fullness of the upper discharge tray 22 is disposed, and the detection lever 39 is supported by a support pin.
42, the detection lever 39 is moved to one side when the discharge sheet is discharged to the upper discharge tray 22.
39a is pushed up by the sequentially increasing discharge sheet and the support pin 4
2, the upper discharge tray 22 is full, and the other side 39b of the detection lever 39 is full.
When it is separated from the sensor, the fullness sensor 40 outputs a fullness detection signal.

An upper fullness detector 45 for detecting the fullness of the additional output tray 32 is disposed below the upper cover 43 of the sheet stacking device 31, and the upper fullness detector 45 includes:
It has the same configuration as the above-described fullness detection device 41, and includes an upper detection lever 47 rotatably supported by an upper support pin 46 and an upper fullness sensor 49, and detects the fullness of the additional discharge tray 32 to be full. Output a detection signal.

Further, the laser beam printer M1 is provided with a control unit 44 comprising a microcomputer (CPU) or the like and controlling each unit of the printer M1, and as shown in FIG. The full sensor 40, the solenoid 37, the upper full sensor 49, and the like are connected. Then, when an upper discharge tray full detection signal is input from the full sensor 40, the solenoid 37 is turned on, the additional flapper 36 is displaced, and the transport direction of the discharged sheet is switched to the additional discharge tray 32 side.

Further, the control unit 44 is provided with a stop means 50 for controlling the image forming unit 3 to stop the image forming operation based on the detection signal of the additional discharge tray being full by the upper full sensor 49. When a full detection signal is input from the full sensor 49, the image forming operation of the image forming unit 3 is automatically stopped.

The electrical connection between each part of the sheet stacking apparatus 31 and the apparatus main body 1 is performed by a known means such as a connector.

The operation of each part of the sheet stacking device 31 is controlled so as to be performed at a predetermined timing in conjunction with each part of the apparatus main body 1 as shown in FIG.
Is set to be on by the detection lever 39 while the upper discharge tray 22 is discharging the discharge sheet, and is set to be turned off at the timing when the upper discharge tray 22 becomes full of discharge sheets. Then, the solenoid 37 is driven with a delay time from the time when the full sensor 40 is turned off, and the additional flapper 36 is displaced to switch the conveyance direction of the discharge sheet to the additional discharge tray 32 side. That is, during the delay time, the sheet in the curved conveyance path 26 is discharged to the upper discharge tray 22 so that the sheet is not jammed by the additional flapper 36.

When the discharged sheets are discharged and stacked in the additional discharge tray 32 and become full, the upper full sensor 49 is turned off by the upper detection lever 47, and the apparatus main body 1 and the sheet stacking device 31 are turned off.
The image forming operation of the apparatus main body 1 is automatically stopped at a timing after all the discharge sheets in the inside have been discharged to the additional discharge tray 32.

Next, the driving of the additional discharge roller pair 35 of the sheet stacking device 31 will be described with reference to FIG.

A main body side gear 53 is provided coaxially with the discharge roller 27 of the apparatus main body 1. Further, the sheet stacking device 31 is provided with a lower gear 55 that meshes with the main body side gear 53 when the sheet stacking device 31 is mounted on the apparatus main body 1. A pulley 56 is provided. Further, an upper pulley 57 is provided coaxially with the lower roller 35b of the additional discharge roller pair 35, and a belt 59 is wound between the upper pulley 57 and the lower pulley 56.
The rotation from the discharge roller 27 is
3. The additional discharge roller pair 35 rotates by being transmitted to the lower roller 36b of the additional discharge roller pair 35 via the lower gear 55, the lower pulley 56, the belt 59, and the upper pulley 57.

Note that a clutch may be disposed on the lower gear 55 to stop the rotation of the additional discharge roller pair 35 when the discharge sheet is being discharged to the upper discharge tray 22 of the apparatus main body 1. .

Further, as shown in detail in FIG. 6, the laser beam printer M1 is provided with a curved conveying path for the upper cover 60 above the discharge section 21.
The upper cover 26 and the upper guide 26a are detached when the sheet stacking device 31 is mounted.

Further, as shown in FIG. 7, a movable cover 61 is disposed above the sheet stacking device 31.
Is integrally formed with an upper guide 33a constituting the additional transport path 33, is supported by a hinge 62 so as to be openable and closable, and is movable when a discharge sheet jam occurs in the additional transport path 33. The cover 61 and the upper guide 33a are opened, the additional conveyance path 33 is opened, and the jammed sheet is removed.

Since the present embodiment is configured as described above, the upper cover 60 of the paper discharge unit 21 of the apparatus main body 1 is removed (see FIG. 6), and the sheet stacking device 31 is mounted on the upper part of the paper discharge unit 21. (See FIG. 2). At this time, the additional flapper 36 is
26 and the additional conveyance path 33,
55 meshes with the main body side gear 53.

Then, the discharged sheet P fixed by the fixing device 20 is first guided to the discharge flapper 29, and further expanded.
The sheet is conveyed along the curved conveying path 26 by the
From the upper discharge tray 22 in a face-down state. When the discharge sheets P are sequentially discharged and stacked on the upper discharge tray 22 and reach a certain height, the detection lever of the full-state detection device 41 located opposite to the upper discharge tray 22.
39 rotates counterclockwise around the support pin 42, and when the upper discharge tray 22 becomes full, the other side 39 of the detection lever 39
b is separated from the full sensor 40, and the upper discharge tray 22 is detected to be full, and the full sensor 40 outputs a full detection signal to the control unit 44.

Therefore, the image forming operation is temporarily stopped by the control of the control unit 44, and the solenoid 37 is applied to the additional flapper.
36 is displaced, and the conveyance direction of the discharge sheet P is
Switch to 32 side. Then, the image forming operation is restarted, and the discharged sheet P is conveyed through the additional conveyance path 33 and discharged from the additional discharge roller pair 35 onto the additional paper discharge tray 32.

Further, when the discharge sheets P are sequentially discharged and stacked on the additional discharge tray 32 and the additional discharge tray 32 becomes full, the upper detection lever 47 of the upper full detection device 45 facing the tray 32 rotates. The upper discharge sensor 32 is separated from the upper full sensor 49, and the full output tray 32 is detected to be full.
Is output to the control unit 44. And
Based on a full detection signal from the upper full sensor 49,
The image forming operation of the apparatus main body 1 is stopped by the stopping means 50 of the control unit 44 (see FIG. 8).

As a result, when the discharged sheets are full in the upper discharge tray of the apparatus main body 1, the conveyance direction of the discharged sheets is automatically switched to the additional discharge tray side, so that the stacked capacity of the discharged sheets is increased, and the operator is required to move upward. It is possible to eliminate the trouble of removing the discharge sheets stacked on the discharge tray halfway. Further, when the additional discharge tray is full, the image forming operation of the apparatus main body is stopped, so that a problem such as a jam due to excessive stacking of discharge sheets and a drop of sheets from the additional discharge tray can be solved. Further, the driving of the sheet stacking apparatus to be added is performed from the apparatus main body side, so that an increase in cost can be suppressed.

Next, a second embodiment in which a plurality of sheet stacking devices are added will be described.

In the paper output unit 21 of the laser beam printer of the present embodiment,
As shown in FIG. 9, a unitized twenty-first sheet stacking device 31a is mounted, and a unitized second sheet stacking device 3a is provided above the first sheet stacking device 31a.
1b is attached.

The first and second sheet stacking devices 31a and 31b are configured in the same manner as the sheet stacking device 31 in the first embodiment. ) Are omitted.

In addition, the additional transport path 33 of these sheet laminating devices 31a and 31b,
Auxiliary transport rollers 63, 63 'are arranged at 33', respectively. The auxiliary transport rollers 63, 63 'assist the transport of the discharged sheet P in the additional transport paths 33, 33'.

Then, when the discharge sheet is discharged onto the upper discharge tray 22 of the laser beam printer and the discharge tray 22 becomes full, the full sheet detecting device 41 of the first sheet stacking device 31a outputs the discharged sheet to the above-described embodiment. In the same manner as described above, the fullness of the upper discharge tray 22 is detected, the additional flapper 36 of the first sheet stacking device 31a is displaced, and the conveyance direction of the discharged sheet is changed to the additional discharge tray 32 And the discharge sheet is discharged onto the additional discharge tray 32.

Further, when the discharge sheets are sequentially discharged and stacked on the additional discharge tray 32, and the additional discharge tray 32 of the first sheet stacking device 31a becomes full, the full detecting device 41 of the second sheet stacking device 31b. ′, The delivery direction of the discharge sheet is switched to the additional discharge tray 32 ′ side of the second sheet stacking device 31b, and the discharge sheet is discharged onto the additional discharge tray 32 ′. Is done.

The discharged sheets are sequentially discharged and stacked on an additional discharge tray 32 'of the second sheet stacking device 31b, and the tray 3
When 2 'is full, the full state is detected by the upper full state detector 45, and the image forming operation of the apparatus main body 1 is stopped.

In this embodiment, two sheet stacking devices 31 are used.
a, 31b, but not limited to this, by removing the movable cover 61 of the upper second sheet stacking device 31b,
Another unit for stacking sheets can be further added.

Further, the drive of the additional discharge roller pair 35, 35 'of the unitized sheet stacking devices 31a, 31b is performed in the first sheet stacking device 31a, as in the previous embodiment. 35 is connected to the discharge roller 27 of the apparatus main body 1, and in the second sheet stacking device 31b, the additional discharge roller pair 35 'is connected to the additional discharge roller pair 35 of the first sheet stacking device 31a. And supplied from the apparatus main body 1 side.

As a result, the number of discharge trays for storing sheets can be easily increased, and the labor of the operator can be further reduced.

In the above-described first and second embodiments, the fullness detecting device that detects fullness by moving the detection lever is used. However, the present invention is not limited to this, and as shown in FIG. A full detector 66 may be used. That is, the fullness detecting device 66 detects the fullness by reading the change in the reflection of the light emitted from the reflection type optical sensor 65 when the upper discharge tray 22 becomes full.

As a result, the occurrence of a jam can be reduced due to a small portion protruding to the upper sheet discharge tray 22, the amount of stacked sheets can be increased, and a mechanical malfunction can be avoided.

Next, a description will be given of a third embodiment in which the present invention is applied to a laser beam printer in which image forming units are vertically arranged.

The same functional portions as those of the above-described conventional laser beam printer M 'are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 11, the laser beam printer M2 of this embodiment has an apparatus main body 1 and an image forming section 3 vertically arranged inside the apparatus main body 1. An optical system 12 is provided adjacent to the image forming unit 3, and a paper feed unit 13 is provided at the top of the apparatus main body 1. Further, a paper discharge unit 21 having a curved conveyance path 26 and the like is provided at one lower side of the apparatus main body 1 (the lower right side in the figure). The paper ejection tray 70 is arranged to protrude.

Further, a sheet stacking device 71 is provided on the downstream side of the paper discharge section 21.
Are removably arranged along the inclined cover 1a of the apparatus main body 1, and the sheet stacking device 71 is configured similarly to the sheet stacking device 31 of the above-described embodiment. That is, the sheet stacking device 71 includes an additional discharge tray 32, an additional conveyance path 33, an additional discharge roller pair 35, and an additional flapper connected to a solenoid.
36, a full detector 41 and an upper full detector 45 are provided, and an auxiliary transport roller 63 is disposed in the additional transport path 33.

Then, similarly to the above-described first embodiment, the discharge sheets P are sequentially discharged and stacked on the discharge tray 70 from the discharge rollers 27. When the discharge tray 70 is detected to be full, the sheet is fed in the direction of the additional discharge tray by the additional flapper 36.
The sheet is switched to the side 32, and the discharge sheet P is
Discharged and loaded on top. Then, when the additional discharge tray 32 becomes full, the full discharge is detected and the image forming operation of the apparatus main body 1 is stopped.

In the sheet stacking device 71 of the present embodiment, the upper cover 72 is opened to the back side to facilitate the jam clearance.

Further, since the sheet stacking device 71 is configured to lean against the inclined cover 1a of the apparatus main body 1, the mounting is easy, and the sheet stacking device can be easily added on the sheet stacking device as described above. Can be.

(G) Effects of the Invention As described above, according to the present invention, when the discharge tray is full of sheets, the full discharge detecting means provided in the additional discharge tray detects that the discharge tray is full. Since the sheet discharge direction is switched to the additional discharge tray side, the stacking capacity of the discharged sheets can be increased, and the trouble of removing the sheets from the discharge tray during the complicated sheet discharge can be eliminated.

In addition, the fullness detecting means for detecting the fullness of the output tray is
Since it is provided on the additional discharge tray, the configuration on the image forming apparatus main body side can be simplified.

[Brief description of the drawings]

1 to 8 are views showing each part of a laser beam printer according to a first embodiment of the present invention. FIG. 1 is a side view of the laser beam printer, and FIG. FIG. 3 is a side sectional view showing a sheet stacking apparatus, FIG. 3 is a block diagram showing each unit connected to a control unit, FIG. 4 is a timing chart, FIG.
FIG. 6 is a side sectional view showing a sheet discharging unit before the sheet stacking device is mounted, FIG. 7 is a side sectional view showing a state in which the movable cover of the sheet stacking device is opened, and FIG. 8 is a flowchart. 9 is a side sectional view of the sheet stacking apparatus according to the second embodiment, FIG. 10 is a side sectional view of the sheet stacking apparatus in which the reflection type optical sensors in the first and second embodiments are arranged, and FIG. Is a side sectional view of a laser beam printer in which an image forming unit according to a third embodiment is vertically arranged, and FIG. 12 is a side view of a conventional laser beam printer. M1 ... Image forming device (laser beam printer), 21 ...
... Sheet discharge unit (discharge unit), 22 ... Discharge tray (upper discharge tray), 31 ... Sheet stacker, 32 ... Expansion discharge tray, 36 ... Switching means (expansion flapper), 41 ... ... full detecting means (full detecting apparatus), 45 ... second full detecting means (upper full detecting apparatus), 50 ... stopping means.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B65H 29/60 B65H 31/22

Claims (3)

(57) [Claims] 1. A sheet discharging unit having a discharge tray for storing discharged sheets, and a sheet stacking device mounted on the sheet discharging unit, wherein the sheet stacking device stores the discharged sheets. A discharge tray for detecting the fullness of the discharge tray, and switching the discharge direction of the discharge sheet to the additional discharge tray side based on the fullness detection of the fullness detection means. An image forming apparatus comprising: 2. The sheet stacking apparatus according to claim 1, wherein the sheet stacking device includes a switching unit that switches a discharge direction of the discharge sheet to the additional discharge tray based on the fullness detection of the fullness detection unit. Image forming device. 3. The apparatus according to claim 1, further comprising: a second full detecting means for detecting the fullness of the additional paper discharge tray at a position of the sheet stacking device facing the additional paper discharge tray, and detecting the fullness of the second full paper detecting means. The image forming apparatus according to claim 1, further comprising a stop unit configured to stop the image forming operation based on the stop unit.