JP2002304034A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely stack recording papers in a compact space, to attain space- saving, and to surely utilize the merit of a vertical arrangement. SOLUTION: In the case where the apparatus body 1 is horizontally laid, a horizontal stack part 14 for storing the image-forming recording paper 6 while turning the image forming surface downward after the paper is discharged from the apparatus body 1 is arranged on the top face of the apparatus body 1, on the other hand, in the case the apparatus body 1 is vertically laid, a vertical stacker member 31 which is attached to the apparatus body 1 while facing the horizontal stack part 14 is detachably loaded, and a space for stacking the recording paper 16 is formed between the horizontal stack part 14 and the vertical stacker member 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a printer for recording an image on a sheet of plain paper or the like, and more particularly, to an image forming apparatus which can be installed in multiple directions such as vertical and horizontal. About.

[0002]

2. Description of the Related Art Generally, in an image forming apparatus configured as a latent image forming type such as an electrophotographic recording apparatus for recording an image on plain paper, after forming an electrostatic latent image on a photosensitive drum, By supplying the powder developer to the photosensitive drum by the developing device, the electrostatic latent image on the photosensitive drum is developed with the powder developer to be visualized. Furthermore, after transferring the image of the powder developer on the photosensitive drum onto a sheet (recording paper) of plain paper or the like, the sheet is separated from the photosensitive drum, and the image of the powder developer on the sheet is fixed by a fixing device. It is fixed to the sheet.

[0003] In a developing step in a developing device of such an image forming apparatus, a developer having a carrier and a toner,
Alternatively, a developer containing only toner is supplied to the photosensitive drum. If the internal toner is consumed and exhausted, the development cannot be continued. Therefore, it is necessary to detect the empty state of the internal toner. FIG. 2 shows a conventional toner empty detection mechanism.
Referring to FIG. 23, as shown in FIG. 23, a toner detection sensor 91 is attached to the outside of the bottom surface of the toner hopper 90 that stores toner in the developing unit. The toner detection sensor 91 generates and outputs a voltage corresponding to the remaining amount of toner in the toner hopper 90.

A comparator 92 for comparing the detection voltage with a fixed slice voltage (threshold voltage) is provided. The comparator 92, as shown in FIG. Is output below the slice voltage.

When the developer contains a magnetic toner, for example, a magnetic permeability sensor is used as the toner detection sensor 91. The output voltage of the magnetic permeability sensor has characteristics as shown in FIG. That is, when the toner amount is small (range of 10 g or less), the output voltage of the magnetic permeability sensor shows a linear characteristic according to the remaining amount of toner. Therefore, the toner empty can be detected in a state where the toner amount is small.

The conventional technique described above with reference to FIGS. 23 to 25 has the following problems. The output voltage of the toner detection sensor 91 is at most about 5 V as shown in FIG.
The output voltage tends to vary, and toner empty cannot be accurately detected by a method based on a constant slice voltage.

In particular, if the developing device is made detachable and a toner detecting sensor 91 is provided on the apparatus main body side, the output voltage from the toner detecting sensor 91 becomes smaller, and the output voltage is further affected by the output voltage. There has been a problem that the toner empty cannot be detected accurately.

The applicant of the present invention has proposed a toner empty detection method capable of solving the above-mentioned problem in Japanese Patent Application No. 5-28.
No. 7654 (filed on October 22, 1993). The invention described in this application is a toner empty detection method in which a control circuit takes in an output of a toner detection sensor for detecting toner in a toner hopper and detects toner empty. And comparing the captured value with the average value of the output of the toner detection sensor during the previous detection cycle, and counting the number of times the captured value has become smaller than the average value during a predetermined detection cycle. And calculating an average value of the captured values during the detection cycle, and comparing the count value with a predetermined value to generate an empty output when the count value becomes larger than the predetermined value. I have.

According to this empty detection method, the following effects can be obtained. Since the toner empty state is detected at a relative level by comparing the output value of the toner detection sensor with the average value during the previous detection cycle, it is possible to eliminate the influence of the variation in the output voltage of the toner detection sensor.

At this time, if the toner empty state is detected by using only the comparison result between the output value of the toner detection sensor and the average value, the toner amount changes due to the rotation of the agitator (supply roller) in the developing device. When the output value of the toner detection sensor decreases, the toner empty state may be erroneously detected. However, in the empty detection method described above, the number of times the captured value has become smaller than the average value during a predetermined detection cycle is counted,
Since the count value is compared with a predetermined value and an empty output is generated when the count value becomes larger than the predetermined value, the toner empty state can be accurately detected even for the toner that fluctuates due to agitation. be able to.

[0011]

The inventor of the present invention has further diligently studied the realization of an image forming apparatus capable of outputting an image with no inferiority in both horizontal and vertical installations. I found such a problem.

That is, normally, when the apparatus main body is installed in the vertical direction, the installation space (area occupied by the apparatus) is smaller than when the apparatus main body is installed in the horizontal direction. Therefore, the vertical installation is performed for the purpose of saving space. Often. However, when the apparatus main body is actually installed in the vertical direction, the same stacking space as in the case of horizontal installation is required due to poor stackability of printed sheets, and as a result, the apparatus main body is set vertically. The benefits are halved. Further, since the printed sheets are stacked on the printing surface, it is necessary to change the order of the printed sheets after the printing is completed, which causes a problem that it takes time and effort.

The present invention has been devised in view of the above-described problems, and can reliably stack recording papers in a compact space, contribute to space saving, and make full use of the advantages of the vertical arrangement. It is an object to provide an image forming apparatus.

[0014]

In order to achieve the above-mentioned object, an image forming apparatus according to the present invention (Claim 1) is characterized in that the apparatus main body is placed in a horizontal position and the apparatus main body is placed in a vertical direction. It is operable in any of the vertically installed state and the installed state, and when the apparatus main body is in the horizontal state, the recording paper after image formation discharged from the apparatus main body is A horizontal stack that can be accommodated with the image forming surface downward is formed on the upper surface of the apparatus body, and faces the horizontal stack when the apparatus body is in the vertical state. Wherein a vertical stacker member attached to the apparatus main body is detachably provided, and a space for stacking recording paper is formed between the horizontal stack portion and the vertical stacker member. I have.

At this time, when the apparatus main body is in the vertical position, a paper discharge port for discharging the recording paper from the apparatus main body to the stack space is arranged below,
A lower space may be formed at a lower portion of the horizontal stack portion below the paper discharge port (Claim 2), or the recording paper discharged from the paper discharge port may be horizontally laid. The vertical stacker member may be provided with a pressing member capable of pressing the stacker side of the vertical stacker (claim 3), or the vertical stacker member may be formed in a U-shape. Claim 4).

With the above arrangement, in the image forming apparatus of the present invention (claim 1), when the apparatus main body is in the vertical state, the vertical stacker member is attached to the apparatus main body, so that the horizontal stack section is provided. Since a space for stacking recording paper is formed between the stacker and the vertical stacker member, the recording paper can be reliably stacked in a compact space.

At this time, when the main body of the apparatus is in the vertical position, the recording paper discharged from the lower discharge port drops into the lower space when the entire recording paper is discharged from the discharge port. That is, since the sheets are stacked with the image forming surface facing the side of the horizontal stack section, the recording sheets can be reliably stacked in a page order (face-down stack) (claim 2).

Further, by pressing the recording paper discharged from the paper discharge port toward the horizontal stack portion by the pressing member, the recording sheet can be stacked with the image forming surface facing the horizontal stack portion, as described above. The recording sheets can be reliably stacked in the page order, and can be stably stacked regardless of the curl state of the recording sheets. Furthermore, since the vertical stacker member is U-shaped, the recording paper after image formation can be taken out regardless of the size of the recording paper.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. (1) Description of Basic Configuration of Control System in Image Forming Apparatus of First Embodiment First, a basic configuration of a control system in the image forming apparatus of the present embodiment will be described with reference to FIG. FIG. 3 is a block diagram showing the basic configuration.

The image forming apparatus of this embodiment is an image forming apparatus having a structure that can be installed in multiple directions, and basically has an installation direction detecting section 2 and a control section 3 as shown in FIG. It is configured. Here, the installation direction detection unit 2 detects the installation direction of the apparatus main body, and the control unit 3
According to the installation direction detected by the installation direction detection unit 2,
The operation of the apparatus main body is controlled.

The control unit 3 according to the present invention includes a plurality of control sequence units 4 for setting control conditions according to the installation direction for each installation direction, and a plurality of control sequence units 4 for the installation direction detected by the installation direction detection unit 2. A control condition selecting unit 5 for selecting a corresponding control sequence unit from a plurality of control sequence units (mechanical control firmware) 4 is provided.

In the image forming apparatus of the present invention described above with reference to FIG. 3, the installation direction of the apparatus main body is detected by the installation direction detecting unit 2, and the control condition selecting unit 5 includes a plurality of control sequence units corresponding to the installation direction. Since the operation in the apparatus main body is controlled by being selected from the control sequence unit 4, control can be performed under control conditions according to the installation direction, and the apparatus can be operated under control suitable for the installation direction. become.

(2) Description of Structure of Image Forming Apparatus FIG. 1 is a longitudinal sectional view schematically showing the structure of an image forming apparatus as one embodiment of the present invention, and FIG. 4 is formed on a paper cassette of this embodiment. FIG. 5 is a side view showing a schematic structure of an installation direction detecting unit (optical sensor) according to the present embodiment. FIG. 6 is a horizontal installation state of the image forming apparatus according to the embodiment. FIG. 7 is a perspective view showing the image forming apparatus of this embodiment in a vertically installed state (vertical installation state). In this embodiment, a case where the image forming apparatus is a cleanerless electrophotographic printer will be described.

In FIG. 3, reference numeral 20 denotes a photosensitive drum. The photosensitive drum 20 is formed by coating a function-separable organic photosensitive member with a thickness of about 26 μm on, for example, an aluminum drum having an outer diameter of 24 mm. It is driven to rotate at a peripheral speed of 25 mm / sec. Reference numeral 21 denotes a pre-charger.
Reference numeral 1 denotes a non-contact type charger for uniformly charging the surface of the photosensitive drum 20 to, for example, -650 V. The non-contact type charger includes, for example, a scorotron.

Reference numeral 22 denotes an optical unit. The optical unit 22 forms an electrostatic latent image on the surface of the photosensitive drum 20 by exposing the uniformly charged photosensitive drum 20 to an image. It is configured using an LED optical system that combines a LED array and a selfoc array.
The optical unit 22 exposes the photosensitive drum 20 to an image according to an image pattern, thereby forming an electrostatic latent image of −50 to −100 V on the photosensitive drum 20.

Reference numeral 23 denotes a developing unit which supplies a developer comprising a magnetic carrier and a magnetic toner to the surface of the photosensitive drum 20 to develop and visualize an electrostatic latent image on the photosensitive drum 20. (The details will be described later with reference to FIGS. 8 and 9). Reference numeral 24 denotes a developing roller for transporting the developer to the photosensitive drum 20 in the developing unit 23, and reference numeral 25 denotes a toner cartridge (toner hopper). The toner cartridge 25 is filled with a developer composed of a magnetic carrier and a magnetic toner. Replaceable developing unit 23
Attached to.

A transfer unit 26 electrostatically transfers the toner image on the photosensitive drum 20 onto the recording paper (sheet, paper) 6.
The transfer unit 26 is formed of, for example, a corona discharger, and applies a voltage of +5 to +10 kV from a power supply to a corona wire to generate electric charges by corona discharge, thereby charging the back surface of the recording paper 6 and charging the photosensitive drum 20. The upper toner image is transferred onto the recording paper 6. As a power source, it is desirable to use a constant current source capable of reducing a decrease in transfer efficiency due to the environment by supplying a constant amount of charge to the recording paper 6.

Reference numeral 27 denotes a fixing unit for thermally fixing the toner image on the recording paper 6. The fixing unit 27 includes, for example, a heat roller having a halogen lamp (see reference numeral 52 in FIG. 2) as a heat source therein, The recording paper 6 is heated by the heat roller while applying an appropriate pressure to the recording paper 6 passing between the pressure roller and the heat roller. Is fixed on the recording paper 6. The heat roller and the pressure roller are driven to rotate by a fixing drive unit 53 described later with reference to FIG.

Reference numeral 28 denotes a dispersing (uniform) member. The dispersing member 28 comes into contact with the photosensitive drum 20 to disperse intensively remaining toner on the photosensitive drum 20, and
The toner collection in step 3 can be easily performed, and is made of, for example, a conductive member. Reference numeral 29 denotes a toner sensor (toner detection unit) for detecting the presence or absence (toner amount) of toner in the toner cartridge 25, the details of which will be described later.

Reference numeral 10 denotes a paper cassette for accommodating the recording paper 6, and the paper cassette 10 is located at a lower portion of the apparatus main body 1 (a lower portion when the apparatus main body 1 is placed horizontally as shown in FIG. 6).
, And can be freely attached and detached from the front of the apparatus (left side in FIG. 1). Also, the paper cassette 10
At the center of each side plate 10a on both sides, a claw 10b is provided as shown in FIG.
As shown in FIG. 3, the sheet is formed to protrude from the upper end position to the inside of the sheet cassette 10. When the apparatus main body 1 is installed vertically as shown in FIG. 7 (when the right side in FIG. 1 is installed downward), the recording paper 6 stored in the paper cassette 10 is moved by the claw 10b. The paper is supported so as not to fall inward, and stable paper transport is realized.

A pick roller 11 picks the recording paper 6 in the paper cassette 10 and discharges it from the paper cassette 10. Reference numeral 12 denotes a registration roller. The registration roller 12 collides with the recording paper 6 discharged from the paper cassette 10 by the pick roller 11 to align the leading ends of the recording paper 6, and then transfers the recording paper 6 to the transfer device 26. To be transported.

Reference numeral 13 denotes a paper discharge roller.
Indicates the recording paper 6 on which the toner image has been thermally fixed by the fixing device 27.
Is discharged to the stacker 14. Reference numeral 7 denotes a transport path through which the recording paper 6 is guided and passed by the rollers 11 to 13 described above. The stacker 14 functions as a stack unit for horizontal placement, is provided on the upper surface of the apparatus main body 1 (the upper part when the apparatus main body 1 is placed horizontally as shown in FIG. 6), and is discharged by the paper discharge rollers 13. Recording paper 6
Is received and accommodated with the image forming surface facing down (that is, face down).

In this embodiment, the apparatus body 1 is
When the vertical stacker member 31 is set in the vertical position shown in FIG. 3, the vertical stacker member 31 is attached to the apparatus main body 1 so as to face the stacker 14, and the stacker of the recording paper 6 is stacked between the horizontal stacker 14 and the vertical stacker member 31. A space is formed. This vertical stacker member 31 is detachable from the apparatus main body 1, and as shown in FIG.
It has a concave portion 31A in the center and is formed in a U-shape.

Further, in the apparatus of this embodiment, when the apparatus main body 1 is in the vertical position shown in FIG. 7, the paper discharge port (paper discharge roller 1) for discharging the recording paper 6 from the apparatus main body 1 to the stack space.
3 is disposed on the lower side, and the lower space of the stacker 14 according to the present embodiment is located below the discharge port (the position of the discharge roller 13). 14
A is formed.

Further, as shown in FIG. 1, a pressing member 8 capable of pressing the lower portion of the recording paper 6 discharged from the paper discharge port onto the stacker 14 is provided on a surface of the vertical stacker member 31 facing the stacker 14. Is attached. This pressing member 8
Is formed of, for example, a polyester film, and applies an appropriate pressing force to the recording paper 6 so that the recording paper 6 can be pressed against the stacker 14 without obstructing the discharge of the recording paper 6 into the stack space. It is.

Reference numeral 15 denotes a printed board on which a control system of an apparatus described later with reference to FIG. 2 is mounted. An optical sensor 15a as an installation direction detecting unit which is a characteristic component of the present invention is provided at an end of the printed board 15. Has been implemented. As shown in FIG. 5, a blocking piece (shutter) 15c is pivotally supported by a rotating shaft 15b inside the optical sensor 15a, and a light receiving element 15d and a light emitting element (not shown) are provided. And a photocoupler (optical sensor) 15e in which are disposed opposite to each other. An end of the blocking piece 15c on the opposite side to the rotation shaft 15b side is a photocoupler 15e.
Has a structure in which the blocking piece 15c rotates around the rotation axis 15b so that the end of the blocking piece 15c always faces the direction of gravity. I have.

When the apparatus main body 1 is, for example, horizontally installed (see FIGS. 1 and 6), the light sensor 15a has an optical path between the light receiving element 15d and the light emitting element as indicated by a solid line. When the device main body 1 is vertically installed (see FIG. 7), the light is emitted from the light receiving element 15d and the light receiving element 15d as shown by a dotted line. The light receiving element 15d receives light from the light emitting element out of the optical path between the light receiving element and the light receiving element 15d to detect and output the vertical installation state.

Reference numeral 16 denotes a power supply for supplying power to each unit of the apparatus, 1
Reference numeral 7 denotes an interface connector. The interface connector 17 is connected to an external cable 17a and is inserted into the apparatus so that the connector 1
5A. Reference numeral 18 denotes an option board for mounting another type of emulator circuit, font memory, and the like.

Reference numeral 33 denotes a fan unit for discharging heat, dust and the like in the apparatus main body 1 to ventilate and cool the inside of the apparatus main body 1. The fan unit 33 is mounted inside the apparatus near the fixing device 27. As shown in FIGS. 6 and 7,
A ventilation hole 34 is formed in the device housing at a position corresponding to the position of the fan unit 33. Through the ventilation hole 34, heat, dust, and the like inside the device are discharged by the fan unit 33. The fan unit 33 is rotatably driven by a fan drive unit 47 described later with reference to FIG.

Reference numeral 35 denotes a light reflection type optical sensor for detecting the end of the recording paper 6 sent out from the fixing device 27.
The optical sensor 35 functions as a recording paper passage detection unit that detects that the recording paper 6 on which an image is formed passes through the fixing device 27. Reference numeral 9 denotes a water-absorbing sheet (for example, a nonwoven fabric) disposed between the process unit including the photosensitive drum 20 and the fixing unit 27.

In FIGS. 6 and 7, reference numeral 5 denotes an operation panel provided on the front of the apparatus main body 1 for inputting instructions for performing various operations. Reference numeral 30 denotes a paper guide. As shown in FIG. 6, when the apparatus main body 1 is installed horizontally, it is attached to the leading end of the stacker 14 and has a function of supporting the leading end of the recording paper 6 discharged to the stacker 14. A paper contact member 30a is slidably provided on the paper guide 30, and the paper contact member 30a abuts on the leading end of the recording paper 6 discharged to the stacker 14 to align the leading end positions. Functioning. The paper contact member 30a can be set at a position corresponding to the size of the recording paper 6 by sliding. Further, reference numeral 32 denotes a stand, and the stand 32 is attached to a side surface below the apparatus main body 1 (installation surface side) when the apparatus main body 1 is vertically installed as shown in FIG. Have.

The basic printing operation of the image forming apparatus constructed as described above will be described. First, the surface of the photosensitive drum 20 is uniformly charged to -650 V by the charger 21 and then the image is exposed by the optical unit 22. Thus, the background portion on the photosensitive drum 20 is −650 V, and the printing portion is −50 to
An electrostatic latent image of -100 V is formed. The developing bias voltage (−300) is applied to the sleeve of the developing roller 24 of the developing device 23.
V) is applied. For this reason, the electrostatic latent image is developed by the developing unit 23 with the magnetic polymer toner that has been negatively charged by stirring with the magnetic carrier in advance, and becomes a toner image.

On the other hand, the recording paper 6 is picked from the paper cassette 10 by the pick roller 11, and
After the tips are aligned at 2, the sheet is conveyed toward the transfer device 26. Then, the toner image on the photosensitive drum 20 is transferred to the transfer device 26.
Is transferred onto the recording paper 6 by electrostatic force. This recording paper 6
Is fixed onto the recording paper 6 by the fixing device 27, and the recording paper 6 after the fixing process is discharged to the stacker 14 by the discharge roller 13 through the U-shaped conveyance path 7.

After the transfer, the residual toner on the photosensitive drum 20 is scattered by the scattering member 28, and the residual charge on the photosensitive drum 20 is also removed by the scattering member 28. Then, the residual toner on the photosensitive drum 20 passes through the charger 21 and the optical unit 22, reaches the developing device 23, and is collected by the developing roller 24 simultaneously with the next developing process. The collected toner is reused in the developing device 23.

Generally, since the transfer efficiency of the developer to the recording paper 6 is not 100%, a small amount of toner (developer) remains on the photosensitive drum 20 by all means. For this reason, it is necessary to remove the residual toner from the photosensitive drum 20, but it is not preferable to provide a cleaner for removing the residual toner. This is because, when removing residual toner using a cleaner, a mechanism for storing the removed toner is required, which increases the size of the apparatus, and the toner removed from the photosensitive drum is not reused and is uneconomical. This is because the disposal of the toner poses an environmental problem.

Therefore, in this embodiment, the above-described cleanerless process is employed. That is, in the cleaner process, the toner concentrated in a part is dispersed by the scattering member 28, the amount of toner per unit area is reduced, and the toner collection by the developing device 23 becomes easy. Further, the filter effect of the ion shower in the charger 21 can be suppressed, and the charging potential on the photosensitive drum 20 can be made uniform. In addition, the filter effect of the exposure in the image exposure process can be suppressed, and the image on the photosensitive drum 20 can be appropriately exposed. There is an effect that can be.

In such a cleanerless process, a mechanism for discarding the toner and a space for storing the waste toner are not required, so that the apparatus can be reduced in size, and there is no toner that does not contribute to printing, so that it is economical. . Further, since toner is not discarded, environmental protection is avoided. Further, to remove the toner on the photosensitive drum 20 with the cleaner, the surface of the photosensitive drum 20 is scraped with the cleaner, but since the cleaner is not used, the photosensitive drum 20 is not used.
There are also advantages such as a longer life of the device.

In the recording process of the image forming apparatus shown in FIG. 1, as described above, the toner is uniformly charged by the charger 21 while the toner is adhered on the photosensitive drum 20, and the image is exposed by the optical unit 22. The developing unit 23 performs the development simultaneously with the recovery of the transfer residual toner. An important point in this recording process is to collect the toner on the photosensitive drum 20 at the same time as the development, and a description will be given of a case where the photosensitive drum 20 is negatively charged and the toner is also negatively charged. The surface potential of the photosensitive drum 20 is set to −50 to −1000 V by the charger 21. The exposed portion of the photosensitive drum 20 whose potential has been reduced by image exposure has its potential reduced to 0 to several tens of volts, and forms an electrostatic latent image. On the other hand, at the time of development, a developing bias voltage (for example, −300 V) substantially intermediate between the surface potential and the latent image potential is applied to the developing roller 24 of the developing device 23.

In the developing step, the negatively charged toner adhering to the developing roller 24 adheres to the electrostatic latent image on the photosensitive drum 20 by electrolysis formed by the developing bias voltage and the latent image potential, thereby forming a toner image. To form In the cleanerless process, at the same time as the developing step, the transfer residual toner dispersed on the photosensitive drum 20 in the uniformizing process by the scattering member 28 is discharged from the photosensitive drum 20 by electrolysis formed by the surface potential and the developing bias potential. Developing roller 2
Collected in 4.

Further, in the 1.5-component developing method, the magnetic brush (not shown) formed on the developing roller 24 comes into contact with the photosensitive drum 20, and the mechanical sweeping force of the magnetic brush causes the residual toner to be mechanically cleaned. This will reduce the target adhesion. In addition, magnetic attraction between the carrier of the magnetic brush and the residual toner (magnetic toner) is generated. This makes it easier to collect the residual toner.

Such an image forming apparatus can be extremely miniaturized, for example, because it does not have a cleaner.
In the apparatus shown in FIG. 1, the length of the apparatus main body including the paper cassette 10 is 350 mm, the width is 345 mm,
The height is 130 mm. Therefore, it can be easily installed on a desk as a printer for personal use. In the image forming apparatus according to the present embodiment, the sheet cassette 10 shown in FIG.
Even in a horizontal installation (horizontal installation) state in which the apparatus main body 1 is set so that the paper main body 1 is parallel to the installation surface, the apparatus main body 1 is set so that the paper cassette 10 shown in FIG. Image formation can be performed even in the state of vertical installation (vertical installation).

In the horizontal state shown in FIG.
A paper guide 30 is attached to the leading end of the recording paper 6, and the leading end of the recording paper 6 discharged to the stacker 14 is supported by the paper guide 30.
Are aligned. Further, the paper cassette 10 can be attached and detached from the front side of the apparatus so that sheets can be easily supplied, and the operation panel 5 can be easily operated from the front side of the apparatus. Further, the recording paper 6 is also discharged toward the apparatus front side along the stacker 14 and the paper guide 30, so that the recording paper 6 can be easily and smoothly taken out from the apparatus front side.

In the vertical position shown in FIG. 7, the apparatus main body 1 is placed on the installation surface with the interface connector 17 (see FIG. 1) side of the apparatus main body 1 facing downward. At this time, the vertical stacker 31 for suppressing the falling of the recording paper 6 discharged to the stacker 14 is attached to the stacker 14 of the apparatus main body 1 so that the falling of the recording paper 6 even in the vertical setting state. Can be prevented. Further, by attaching the stand 32 to the side surface of the lower part (installation surface side) of the apparatus main body 1, even if the apparatus main body 1 is installed vertically,
The device itself can be prevented from overturning, and the device main body 1 can be stably supported in the vertically installed state.

In the image forming apparatus of this embodiment described above, when the apparatus main body 1 is in the vertical position, the stacker member 31 for vertical installation is attached to the apparatus main body 1 so as to face the stacker 14, whereby the stacker is mounted. A space for stacking the recording paper 6 can be formed between the stacker 14 and the vertical stacker member 31. Therefore, the recording paper 6 can be reliably stacked in a compact space, contributing to space saving.
The advantages of the vertical arrangement can be fully utilized.

When the apparatus main body 1 is in the vertical position, the recording paper 6 is entirely discharged from the paper discharge port (discharge roller 13).
When the recording paper 6 is discharged from the printer, it falls into the lower space portion 14A, and is stacked with the image forming surface facing the stacker 14, so that the recording paper 6 can be reliably stacked in the page order (printing order) (face-down stacking). Therefore, it is possible to save the trouble of rearranging the order of the recording paper 6 after the image formation, and to greatly improve the workability.

By pressing the recording paper 6 toward the stacker 14 by the pressing member 8, the image forming surface can be stacked with the stacker 14 facing the stacker 14, and the recording paper 6 can be reliably placed in the page order (printing order) as described above. ), The work of reordering the recording paper 6 after the image formation is completed can be omitted, and the workability is greatly improved. Depending on the curl state of the recording paper 6, the stacking property may be significantly deteriorated. However, as described above, the lower part of the recording paper 6 is pressed toward the stacker 14 by the pressing member 8 to curl the recording paper 6. There is also an advantage that the stack can be stably performed regardless of the state.

Further, since the vertical stacker member 31 has the U-shaped concave portion 31A, the printed recording paper 6 can be very easily taken out regardless of the size of the recording paper (medium, paper) 6. Can be. In the above-described image forming apparatus of the present embodiment, when the apparatus main body 1 is in the vertical position, the recording paper 6 is formed by the water-absorbing sheet 9 provided between the fixing device 27 and the process section including the photosensitive drum 20. The water vapor generated from the recording paper 6 when passes through the fixing device 27 is absorbed.

In particular, when the apparatus main body 1 is placed vertically, the steam rises toward the process section due to the chimney effect. However, the water vapor is absorbed by the water absorbing sheet 9 as described above. 1, the amount of water vapor is reduced, and it is possible to reliably prevent the water vapor from affecting the process section.

The effect of the water absorbing sheet 9 is effective when the process section (photosensitive drum 20) is in a cooled state and the water vapor is easily condensed before the inside of the apparatus main body 1 reaches a certain temperature. When the inside of the main body 1 reaches a certain temperature, the steam is discharged out of the main body 1 by the operation of the fan unit 33.

In this embodiment, since the charger 21 and the transfer unit 26 are constituted by non-contact type dischargers, the toner on the photosensitive drum 20 is transferred to these units without executing the cleanerless process. It is possible to stably perform uniform charging and transfer without adhesion.

(3) Description of Developing Unit FIG. 8 is a longitudinal sectional view showing a state of the developing unit in a horizontal installation state (see FIG. 6), and FIG. 9 shows a state of the developing unit in a vertical installation state (see FIG. 7). It is a longitudinal cross-sectional view. 8 and 9, 29
Is a toner sensor fixedly provided on the apparatus main body 1 side.
The toner sensor 29 generates a voltage output according to the magnetic force of the magnetic toner, and is constituted by, for example, a magnetic permeability sensor. On the other hand, the developing device 23 is provided detachably with respect to the apparatus main body 1. Therefore, the toner sensor 29 detects the presence / absence (remaining amount of toner) of the internal magnetic toner via the case 23a of the developing device 23.

The developing roller 24 includes a metal sleeve 241 and a magnet 240 having a plurality of magnetic poles provided therein. This developing roller 24
Fixes the magnet 240 inside the sleeve 241,
The rotation of the sleeve 241 conveys a magnetic developer described later. The developing roller 24 is formed, for example, with a diameter of 16 mm, and is driven to rotate at three times the peripheral speed of the photosensitive drum 20 (75 mm / sec).

Around the developing roller 24, a developing chamber 230
Are formed, and the inside of the developing chamber 230 is filled with a 1.5-component developer which is a mixture of a magnetic carrier and a magnetic toner. The developing chamber 230 is provided with the upper partition member 23.
0-1 and the lower bottom 230-2 and have a certain volume.

Therefore, when a certain amount of magnetic carrier is put into the developing chamber 230, the amount of the magnetic toner in the developing chamber 230 also becomes constant, and the consumed magnetic toner is transferred to the toner hopper 2.
When supplied from 31, the amount of developer in the developing chamber 230 is constant, so that the toner concentration is also constant, so that it is not necessary to control the toner concentration. That is, by filling the developing chamber 230 with a carrier amount corresponding to the toner density control point, the toner density is automatically controlled to a predetermined range.

In the developing chamber 230, the developer is always
Because the space around the developing roller 24 is filled, even if the apparatus main body 1 is installed vertically, the developer in the developing chamber 230 is biased,
A situation in which a sufficient amount of developer cannot be supplied to the developing roller 24 can be prevented.

As the developer 60, for example, an average particle size of 40
A mixture of a μm magnetite carrier (magnetic carrier) and a polymerized toner (magnetic toner) having an average particle size of 7 μm manufactured by, for example, a polymerization method is used. Such a polymerized toner has a uniform particle size and a sharp particle size distribution, so that the adhesion between the toner image on the photosensitive drum 20 and the recording paper 6 becomes uniform in the transfer step. For this reason, the electric field in the transfer device 26 becomes uniform, and the transfer efficiency can be improved as compared with the toner obtained by the conventional pulverization method. The transfer efficiency of the pulverized toner, which was 60 to 90%, can be improved to 90% or more by using the polymerized toner. In the case of the polymerized toner, the toner concentration is 5 to 60 wt.
% Is appropriate, and is set to 25 wt% in this embodiment.

Reference numeral 234 denotes a doctor blade.
Is adjusted so that the supply of the developer to the electrostatic latent image on the photosensitive drum 20 does not become excessive or insufficient. The adjustment is performed in the gap between the edge of the doctor blade 234 and the surface of the developing roller 24.
It is adjusted to about 1.0 mm.

Reference numeral 231 denotes a toner hopper filled only with magnetic toner.
A supply roller (agitator) 232 is provided.
By the rotation of the supply roller 232, the toner is transferred to the developing chamber 2
30.

The toner supplied into the developing chamber 230 is applied to the developer conveying force of the sleeve 240 of the developing roller 24,
Due to the magnetic force of the developing roller 24 and the developer regulating function of the doctor blade 234, the developer is stirred in the developing chamber 230,
It is charged to a predetermined polarity and charge amount by friction with the carrier. In this embodiment, the charging sequence of the carrier and the toner is adjusted so as to be negatively charged.

Further, on the upstream side of the doctor blade 234, the distance a (see FIG. 8) between the partition roller 230-1 and the developing roller 24 is adjusted by the height of the magnetic brush (not shown) formed on the developing roller 24. Smaller than Here, the interval a is set to, for example, 2.0 mm. As a result, the magnetic brush on the developing roller 24 is
The magnetic brush receives a force due to the rotation of the developing roller 24. Therefore, the developing chamber 23
The developer agitating property within 0 is enhanced, and a stable toner charge amount can be obtained even in a high toner concentration range.

The inner wall surface 23 of the partition member 230-1
0-4 are formed in a shape along the developing roller 24. That is, the inner wall surface 230-4 is basically
4, the magnetic carrier is formed in an arc shape with the interval a, so that no magnetic carrier stays. Therefore, all the magnetic carrier and the magnetic toner are always stirred and conveyed around the developing roller 24, and the fluctuation of the toner density control value can be prevented.

Further, since all the magnetic carriers and the magnetic toner are agitated, a stable toner charge amount can be expected even in a high toner concentration range. Moreover, the charging effect does not change when the apparatus main body 1 is installed horizontally or vertically. Between the toner hopper 231 and the developing chamber 230,
A toner supply path 235 formed by the tip of the partition member 230-1 and the bottom 230-2 is provided. The toner in the toner hopper 231 is supplied by the toner supply path 235.
The developer is supplied to the developing chamber 230.

The angle between both wall surfaces of the toner cartridge 25 and the toner hopper 231 is set to approximately 45 degrees with respect to the direction of gravity, and the flow direction of the toner is 45 degrees. As a result, as will be described later with reference to FIG. 9, even when the apparatus main body 1 is installed vertically, the toner is smoothly supplied.

Next, the developing device 23 constructed as described above is used.
8 shows the state of the developing device 23 in the horizontal installation state shown in FIG. As shown in FIG. 8, in the present embodiment, in the horizontal installation state, the angle of the wall surface of the toner cartridge 25 and the toner hopper 231 is configured to be approximately 45 degrees with respect to the direction of gravity, so that the toner is The toner flows toward the bottom of the toner hopper 231 and is smoothly supplied to the supply roller 232.

As a result, only the toner supplied by the supply roller 232 enters the toner supply path 235, and the partition member 230-1 functions as a buffer.
The pushing force by the supply roller 232 does not directly affect the toner supply path 235. Accordingly, it is possible to prevent the excessive pushing of the toner, and the toner is supplied by the amount of the toner that has become insufficient in the developing chamber 230.

At this time, since the bottom portion 230-2 is inclined upward with respect to the rotation direction of the developing roller 24, the developing roller 24 has passed through a portion facing the photosensitive drum 20.
Does not leak from the toner supply path 235 into the toner supply chamber 231 through the bottom 230-2. For this reason, the starter carrier in the developing chamber 230 can be prevented from decreasing.
It is possible to stably perform five-component development.

FIG. 9 shows the state of the developing unit 23 in the vertically installed state shown in FIG. As shown in FIG. 9, in the present embodiment, the toner is supplied because the angle of the wall surface of the toner cartridge 25 and the toner hopper 231 is approximately 45 degrees with respect to the direction of gravity even in the vertical installation state. It can be smoothly supplied to the roller 232.

The angle of the wall surface of the toner cartridge 25 and the toner hopper 231 is preferably about 45 ° ± 10 ° with respect to the direction of gravity, in consideration of the angle of repose, in order to carry the toner satisfactorily by its own weight. Good results can be obtained at an angle of about 45 ° ± 5 °.

At this time, as shown in FIG.
The partition member 230-1 stays on the toner hopper 231 side and easily falls from the toner supply path 235 to the developing chamber 230. However, since the protrusion 230-3 of the bottom 230-2 can restrict the toner from dropping in the toner supply path 235, the toner hardly drops. Therefore, the toner is supplied only by the rotation force of the supply roller 232.

That is, the toner pressed by the supply roller 232 once hits the partition member 230-1 by the protrusion 230-3 of the bottom 230-2, and enters the toner supply path 235. As a result, only the toner supplied by the supply roller 232 enters the toner supply path 235, and the partition member 230-1 serves as a buffer, so that the pushing force by the supply roller 232 does not directly become the toner supply force. Therefore, excessive pushing of the toner can be prevented, and the toner is supplied by the amount of the toner that has become insufficient in the developing chamber 230.

As described above with reference to FIGS. 8 and 9, the toner supply capacity to the developing chamber 230 does not change when the apparatus main body 1 is installed horizontally or vertically. However, the toner density in the developing chamber 230 does not change, so that a change in image density can be prevented.

In the case of the vertical installation, there is a possibility that the developer may drop from the developing device 23. However, a magnetic two-component developer is used as the developer, and the developer is applied to the developing roller 24 by a magnetic force. Since the developer is held, the developer hardly falls. In particular, when a magnetic carrier and a magnetic toner are used, both the carrier and the toner are held by the magnet roller of the developing roller 24, so that the developer can be more reliably prevented from dropping, and even in such a vertical installation, the developer can be stably provided. Can be developed.

(4) Description of Control System FIG. 2 is a block diagram functionally showing the structure of the control system of the image forming apparatus according to one embodiment of the present invention. In FIG. Is an installation direction determining unit that determines the installation direction of the apparatus main body 1 based on the output signal of the image forming apparatus. An empty control circuit (control unit) 37 determines the installation direction of the apparatus main body 1 based on the output signal of the toner sensor 29. The toner empty control is performed according to the installation direction of the apparatus main body 1 determined by the above.

The empty control circuit 37 includes a control condition selecting section 38, a horizontal toner empty state judging section (control sequence section) 39, a vertical toner empty state judging section (control sequence section) 40, and an output section 41.
Is configured. Here, the control condition selection unit 38
Is to select the toner empty state determination unit 39 or 40 according to the installation direction from the installation direction determination unit 36.

The horizontal toner empty state judging section 39
Is selected by the control condition selecting unit 38 when the installation direction of the apparatus main body 1 is horizontal, and the output signal of the toner sensor 29 is sampled in a single detection cycle for sampling a predetermined number of times. The toner empty state is determined by comparing the level value with a horizontal slice level value calculated by averaging the level values of the output signal sampled in the previous detection cycle. The detailed operation will be described later with reference to FIGS.

Vertical Toner Empty State Determining Unit 40
Is selected by the control condition selecting section 38 when the installation direction of the apparatus main body 1 is vertical, and the output signal of the toner sensor 29 is sampled in a single detection cycle for sampling a predetermined number of times. A calculation formula [(maximum value−maximum value−
The minimum value) × k + the minimum value; k is, for example, 0.3, is used to determine the toner empty state. The detailed operation will be described later with reference to FIGS.

The output section 41 is provided with an empty state determination section 39.
Alternatively, in response to the determination result from 40, an empty determination output and a near empty determination output are performed, and a release output of the determination is performed. Reference numeral 42 denotes an empty state display unit (toner empty indicator) provided on, for example, the operation panel 5 of the apparatus main body 1. Reference numeral 43 denotes a fan control circuit (control unit). The fan control circuit 43 controls the operation state of the fan unit 33 in accordance with the installation direction of the apparatus main body 1. A fan control unit (control sequence unit) 45 and a vertical fan control unit (control sequence unit) 46 are configured.

Here, the control condition selector 44 selects the fan controller 45 or 46 according to the installation direction from the installation direction determiner 36. The horizontal fan control unit 45 selects a control condition when the apparatus main body 1 is installed in a horizontal direction and the fixing unit 27 and the process unit including the photosensitive drum 20 are in a horizontal installation state where they are arranged substantially horizontally. The vertical fan control unit 46 is provided by the fixing unit 27 when the apparatus main body 1 is installed in the vertical direction.
Is selected by the control condition selecting unit 44 when the process unit is in the vertical position in which the process unit is disposed above the unit.

The detailed operation of the fan control units 45 and 46 will be described later with reference to FIGS. Also, 4
Reference numeral 7 denotes a fan drive unit (motor or the like) that actually receives the control signal from the fan control unit 45 or 46 and drives the fan unit 33. On the other hand, a fixing unit control circuit (control unit) 48 controls the operation state of the fixing unit 27 according to the installation direction of the apparatus main body 1. A fixing unit control unit (control sequence unit) 50 for horizontal mounting and a fixing unit control unit (control sequence unit) 51 for vertical mounting are configured.

Here, the control condition selecting section 49 selects the fixing device control section 50 or 51 according to the installation direction from the installation direction determining section 36. The horizontal fixing device control unit 50 controls the control condition when the apparatus main body 1 is installed in the horizontal direction and the fixing unit 27 and the process unit including the photosensitive drum 20 are arranged in a horizontal direction in a substantially horizontal state. The fixing unit control unit 51 for vertical placement includes a fixing unit 27 in which the apparatus main body 1 is installed in the vertical direction.
Is selected by the control condition selecting unit 49 when the process unit is in a vertically placed state in which the process unit is disposed above.

The detailed operation of these fixing unit control units 50 and 51 will be described later with reference to FIGS. Also, 5
2 is a halogen lamp (heater) whose temperature is actually controlled in response to a control signal from the fixing device control unit 50 or 51;
Reference numeral 53 denotes a fixing device driving unit (motor or the like) that receives a control signal from the fixing device control unit 50 or 51 and actually drives the heat roller or the pressure roller in the fixing device 27 to rotate.

(5) Description of Toner Empty Detecting Method The structure of the image forming apparatus of the present embodiment described above with reference to FIGS. The toner supply amount to the toner sensor (magnetic permeability sensor) 29 is different between the horizontal installation and the vertical installation.

That is, when the horizontal installation state shown in FIG. 8 is compared with the vertical installation state shown in FIG. 9, it is apparent that in the horizontal installation state, the toner is supplied to the toner hopper 231 successively while staying on the bottom side. And the toner sensor 29
Detects the state of reduction of the staying toner on the bottom side. On the other hand, in the vertically installed state, the toner is sequentially supplied while staying in a state where it spreads also to the partition member 230-1 side in the toner hopper 231. The toner sensor 29 detects such spread staying toner. Become. Such a difference increases as the amount of staying toner decreases,
As a result, the toner empty detection becomes unstable in the case of the vertical installation.

Therefore, in the image forming apparatus of this embodiment, when the power is turned on, the installation direction determining unit 36 sets the optical sensor 1
The output signal of 5a is determined to determine whether the apparatus main body 1 is in the horizontal state or the vertical state. If the apparatus main body 1 is in the horizontal state, for example, the control condition selecting unit 38 of the empty control circuit 37 is notified of the fact, and the control condition selecting unit 38 sets the horizontal toner empty state determining unit 3
Select 9.

The horizontal toner empty state judging section 39
Monitors the output state of the toner sensor 29 in accordance with the control sequence. When the output condition becomes equal to or less than a predetermined condition described later, it is determined that the output is empty or near empty, and the determination result is notified to the display unit 42 through the output unit 41. Further, when the determination unit 39 determines that the output state of the toner sensor 29 is equal to or more than a predetermined condition after the operator replenishes the toner, the release state of the empty or near empty state is determined, and the notification state is released through the output unit 41.

Similarly, when the apparatus main body 1 is in the vertical state, the vertical condition toner empty state determining section 40 is selected by the control condition selecting section 38 according to the output signal of the optical sensor 15a. The determination unit 40 monitors the output state of the toner sensor 29 in accordance with the control sequence, and determines that the output condition is equal to or less than a predetermined condition, which will be described later, as empty or near empty, and notifies the display unit 42 via the output unit 41 of the determination result. Is done. Further, when the determination unit 40 determines that the output state of the toner sensor 29 is equal to or more than the predetermined condition after the toner is supplied by the operator, the release state of the empty or near empty state is determined, and the notification state is released through the output unit 41.

The operation of the empty detection by the judging sections 39 and 40 will be described with reference to FIG. First, the empty detection operation by the horizontal toner empty state determination unit 39 will be described. In the case where one rotation of the supply roller (agitator) 232 is, for example, 1.6 seconds, in this embodiment, the detection cycle of the toner sensor 29 is also set to 1.6 seconds. The sampling of the output voltage of the toner sensor 29 for 1.6 seconds is performed, for example, every 10 milliseconds, as shown in FIG. Obtain voltage data.

The determination unit 39 calculates the average value of the output voltage (160 pieces of detection data) during the previous detection cycle as the slice level value for the current detection cycle, and then calculates the average of the output voltages (160 detection data) during the current detection cycle. The number of samplings that have become equal to or less than the average value of the output voltage during the cycle is counted. When a detection cycle in which the number of times of sampling becomes, for example, 80 or more is detected in one detection cycle, the determination unit 39 determines that the state is near empty and causes the display unit 42 to display the fact through the output unit 41.

When the operator replenishes the toner according to the near empty display, the output voltage of the toner sensor 29 increases. Then, the determination unit 39 determines that the number of times of sampling in which the output voltage has become equal to or less than the average value during the previous detection cycle has become, for example, 70 or less, out of the 160 times of sampling.
Is determined, the near empty display on the display unit 42 is released through the output unit 41.

If the toner replenishment is not performed even after the near empty display, and a detection cycle is detected in which the number of samplings that has become equal to or less than the average value of the output voltage in the previous detection cycle becomes 90 or more, for example, the determination unit 39 determines that the toner is empty and causes the display unit 42 to display the fact via the output unit 41.

If the operator supplies toner after the empty display, the output voltage of the toner sensor 29 increases.
Then, of the 160 samplings, the number of times that the output voltage becomes equal to or less than the average value of the output voltage during the previous detection cycle is, for example, 70
If the determination unit 39 determines that the number of times has become less than or equal to
1 to release the empty display on the display unit 42.

Next, the empty detecting operation by the vertical toner empty state judging section 40 will be described. The determination unit 40 of the present embodiment determines the output voltage (1
The maximum value Max and the minimum value Min of the 60 detection data)
And the slice level value for the current detection cycle is
Calculated as [(Max-Min) x 0.3 + Min], and 16
Of the zero samplings, the number of samplings equal to or lower than the slice level value is counted. When a detection cycle in which the number of times of sampling is, for example, 70 or more is detected during one detection cycle, the determination unit 40 determines that the state is near empty and causes the display unit 42 to display the fact through the output unit 41.

If the operator supplies toner in accordance with the near empty display, the output voltage of the toner sensor 29 increases. When the determination unit 40 determines that the number of times of sampling that has become equal to or more than the slice level value calculated based on the output voltage during the previous detection cycle has become 90 or more, for example, out of 160 samplings, the output unit The near-empty display on the display unit 42 is released through 41.

As described above, when the toner empty detection is performed with one rotation of the supply roller (agitator) 232 as one detection cycle, the flow of toner is not stable at the first rotation of the supply roller 232, so that the toner flow is not stable. The output voltage of the toner sensor 29 is unstable. Accordingly, for the first rotation of the supply roller 232, the sensor output is masked and the toner empty detection is not performed in order to prevent erroneous detection. Then, the slice level value is calculated based on the output voltage of the toner sensor 29 obtained at the second rotation of the supply roller 232, and actually,
The above-described toner empty detection is started from the rotation.

Apparatus main body 1 using optical sensor 15a described above
The detection direction of the installation direction of the optical sensor 15a is, for example, a warm-up operation when the power is turned on, an initialization operation when the discharge tray is opened and closed, or after the start of the main motor rotation such as a printing operation. Is read, and the installation direction is determined by the installation direction determination unit 36. The output of the optical sensor 15a is in a high state with the optical path interrupted as shown by the solid line in FIG. 5 when placed horizontally, and becomes low with the optical path opened as shown by the dotted line in FIG. 5 when placed vertically.

The toner empty state judging section 39,
The empty detection by 40 is always performed while the main motor is rotating (during a printing operation), except during a warm-up operation when the power is turned on, and during an initialization operation when the discharge tray is opened and closed. Further, the toner empty state determination unit 3
When near empty is detected by 9 and 40, for example, the empty state display section 42 is blinked. In this state, if the output tray is opened or closed, or the power is turned on.
In the case of / OFF, if the toner empty release level has been reached at the time of initialization, the near empty release is performed (the display section 42 is turned off; the apparatus is in the Ready state), but if the release level has not been reached, the process is continued. The display section 42 blinks. The near empty is the power supply OF
It is also stored in the F state.

Similarly, the toner empty state judging section 3
If the toner empty is detected according to 9, 40,
The empty state display section 42 is turned on, and the apparatus is stopped after the job is completed (Not Ready state). In this state, when the discharge tray is opened and closed, or when the power is turned on / off.
In the case of F, if the toner empty release level has been reached at the time of initialization, the toner empty is released (the display section 42 is turned off; the apparatus is in the Ready state). The display unit 42 is turned on. The toner empty is stored even when the power is off.

Next, a specific empty control operation by the image forming apparatus of this embodiment will be described with reference to FIGS. FIG. 11 shows the operation when the power is turned on, when the discharge tray is opened and closed, and when the toner is not empty. At this time, first, the installation is performed based on whether the output signal from the optical sensor 15a is in a high state or a low state. The installation direction of the apparatus main body 1 is determined by the direction determination unit 36 (step S1).

When the output signal from the optical sensor 15a is in the high state, the control condition selecting section 38 selects the horizontal toner empty state judging section 39 (Step S).
2), the presence or absence of the print unit is determined based on the output voltage ΔV from the toner sensor 29 (step S3).

If the output voltage ΔV from the toner sensor 29 is 0.1 V or less, it is determined that the print unit is not mounted or the toner is empty, and the apparatus is not ready.
It becomes a state (step S8). On the other hand, the toner sensor 29
When the output voltage ΔV from the printer is greater than 0.1 V (when the print unit is attached), the apparatus enters a ready state (step S4).

If it is determined in step S1 that the output signal from the optical sensor 15a is in the low state, the control condition selecting unit 38 selects the vertically placed toner empty state determining unit 40 (step S5). ), Step S
3, the presence or absence of the print unit is determined by the toner sensor 2.
9 based on the output voltage ΔV (step S
6).

When the output voltage ΔV from the toner sensor 29 is 0.1 V or less, it is determined that the print unit is not mounted or the toner is empty, and the apparatus is not ready.
It becomes a state (step S8). On the other hand, the toner sensor 29
If the output voltage ΔV from is greater than 0.1V,
The device enters a ready state (step S7). FIG.
Reference numeral 2 denotes an operation when the power is turned on, when the discharge tray is opened and closed, and when the toner is empty (or near empty). Steps S1 to S3, S5, S6, and S8 are exactly the same as the processing described in FIG. Therefore, the description is omitted.

Horizontal toner empty state judging section 39
Is selected, the toner sensor 29 is determined in step S3.
If it is determined that the output voltage ΔV from is greater than 0.1 V (when the print unit is attached), it is determined whether or not the empty state can be released (step S9).

That is, it is determined whether or not the number of samplings (empty count value) that has become equal to or less than the slice level value in one detection cycle is equal to or less than Z times (for example, 70 times; the remaining amount of toner is 30 g or more). If so, it is determined that toner replenishment (toner cartridge replacement) has been performed, and the empty state is released, and the apparatus is brought into a ready state (step S10). On the other hand, when the empty count value is Z
If it is larger than the number of times, it is determined that toner replenishment has not yet been performed, and the state of toner empty or near empty is continued (step S11).

If the vertical empty toner empty state judging section 40 is selected and it is judged in step S3 that the output voltage ΔV from the toner sensor 29 is larger than 0.1 V (when the print unit is mounted). Determines whether or not the empty state can be released (step S12).

At this time, the number of samplings that have exceeded the slice level value during one detection cycle is F times (for example, 90 times;
It is determined whether the operation has been performed continuously for more than 30 g of the toner remaining amount). If the operation has been performed more than F times, it is determined that toner replenishment (replacement of the toner cartridge) has been performed, and the apparatus is released to perform empty cancellation. Ready state (step S10). On the other hand, if sampling has not been performed consecutively F times or more, it is determined that toner replenishment has not yet been performed, and the state of toner empty or near empty is continued (step S11).

The operation when the horizontal toner empty state judging section 39 is selected will be described with reference to FIG. First, it is determined whether the number of times of sampling (detection count value) that has become equal to or less than the slice level value during one detection cycle is equal to or more than X times (for example, 80 times; the remaining amount of toner is equal to or less than 15 g) (step S13). If it is smaller than X, the normal operation is performed (step S14), and if it is X times or more, the near-empty judgment is output, the blinking display is performed by the empty state display unit 42, and the operator or the like is notified that the near-empty state is present. (Step S15).

Thereafter, it is determined whether or not the toner supply operation has been performed by the operator (step S16). When the toner replenishment operation is performed, it is determined whether the detected count value is equal to or less than Z times (for example, 70 times; the remaining amount of toner is 30 g or more) (step S17). If the detected count value is larger than Z times, the process returns to step S15. If the near-empty display is continuously performed, and if the number is equal to or less than Z times, it is determined that the toner supply operation has been completed, the empty state is released, and the apparatus is read.
The state is changed to the y state (step S22).

If it is determined in step S16 that the toner replenishment operation has not been performed, it is determined whether the detected count value is Y times (for example, 90 times; the remaining amount of toner is 10 g or less) or more (step S18). If the number is less than Y times, the process returns to step S15 and the near empty display is continued, and if the number is more than Y times, a toner empty determination is output, and the empty state display unit 42 lights to display the toner empty state. Notifying the operator etc. that there is, and setting the apparatus to the Not Ready state (step S19).

When the operator performs a toner supply operation in response to the notification of toner empty (step S2).
0), as in step S17, it is determined whether the detected count value is equal to or less than Z times (for example, 70 times; the remaining amount of toner is 30 g or more) (step S21). If the empty display is continuously performed, and if the count is equal to or less than Z times, it is determined that the toner supply operation has been completed, the empty state is released, and the apparatus is read.
The state is changed to the y state (step S22).

The operation when the vertical toner empty state judging section 40 is selected will be described with reference to FIG. 13 and 14, almost the same processing is performed except that the number of comparisons of the count value is different.
Steps S23 to S32 in FIG. 14 correspond to steps S13 to S22 in FIG. 13, respectively.

First, it is determined whether or not sampling that has become equal to or less than the slice level value during one detection cycle has been performed continuously for at least D times (for example, 80 times; the remaining amount of toner is 15 g or less) (step S23). If the number is smaller than the number of times, the normal operation is performed (step S24). If the number of times is equal to or more than D, the near-empty determination is output, the blinking display is performed by the empty state display unit 42, and the operator is notified that the state is near empty. Etc. (Step S2
5).

Thereafter, it is determined whether or not the operator has performed a toner supply operation (step S26). When the toner replenishment operation is performed, it is determined whether or not the sampling that has become equal to or more than the slice level value during one detection cycle has been continuously performed F times (for example, 90 times; the remaining amount of toner is 30 g or more) or more. (Step S27) If it has not continued for F or more times, the process returns to Step S25 and the near empty display is continued, while if it has continued for F or more times, it is determined that the toner supply operation has been completed. , The empty state is released and the device is set to the ready state (step S
32).

If it is determined in step S26 that the toner replenishment operation has not been performed, the number of samplings that has become equal to or less than the slice level value in one detection cycle is E times (eg, 90 times; the remaining amount of toner is 10 g or less). It is determined whether or not the above operation has been performed continuously (step S28). If the number of operations has been smaller than E, the process returns to step S25 to continuously display the near empty state. And the empty state display section 4
2 to display a light to notify the operator or the like that the toner is empty, and to set the device to Not Read.
The state is changed to the y state (step S29).

When a toner replenishment operation is performed by the operator upon notification of toner empty (step S3)
0), as in step S27, it is determined whether or not the sampling that has reached the slice level value or more during one detection cycle has been performed F times (for example, 90 times; the remaining amount of toner is 30 g or more) or more consecutively (step S27). In step S27), if it has not continued for F or more times, the process returns to step S25 and the near empty display is continuously performed. On the other hand, if it has continued for F or more times, it is determined that the toner supply operation has been completed, and the empty state is determined. The state is released and the device is set to the Ready state (step S3).
2).

(6) Description of Fan Control In this embodiment, the process section such as the photosensitive drum 20 and the fixing device 27 are positioned substantially horizontally in the horizontal installation state shown in FIG. 8, but in the vertical installation state shown in FIG. Then, the process unit is located above the fixing unit 27. Further, the recording paper 6 contains moisture, and when this is passed through the fixing device 27, water vapor is generated. For example, when the temperature of the process section is low,
The water vapor condenses and becomes water droplets and adheres. In particular, when the water droplets adhere to the photosensitive drum 20, the deterioration of the photosensitive drum 20 is accelerated and the life is shortened.

In the case of the vertical arrangement, particularly, the water vapor that has risen due to the chimney effect easily becomes water droplets and adheres to the process portion, and is easily affected. Therefore, in the image forming apparatus of this embodiment, when the power is turned on, the installation direction determining unit 36 determines the output signal of the optical sensor 15a and determines whether the apparatus main body 1 is in the horizontal state or the vertical state. decide. If the apparatus main body 1 is in the horizontal state, for example, the control condition selecting unit 44 of the fan control circuit 43 is notified of the fact, and the control condition selecting unit 45 selects the horizontal fan control unit 45.

According to the control sequence, the horizontal fan control unit 45 causes the fan drive unit 47 to rotate the fan of the fan unit 33 immediately after the power is turned on, for example.
Control. On the other hand, when the vertical installation fan control unit 46 is selected by the control condition selection unit 45, the vertical installation fan control unit 46 causes the fan drive unit 47 to rotate the fan, for example, when a predetermined time has elapsed after power-on. Control. As described above, since the fan does not rotate for a predetermined time after the power is turned on, the temperature of the process unit such as the photosensitive drum 20 rises as the temperature of the fixing unit 27 rises.

Further, the vertical fan control unit 46 rotates the fan when the recording paper 6 is conveyed to the fixing device 27 and the leading end of the recording paper 6 is detected by the optical sensor 35, so that the recording paper 6 is rotated. Water vapor generated from the paper 6 is exhausted by the fan unit 33 through the vent hole 34, and a part of the water vapor rises and reaches the process section. However, as described above, the fan is not driven in this embodiment. Since the process section is heated during the predetermined time, dew condensation hardly occurs and the process section is hardly affected by water droplets.

If the optical sensor 35 does not detect the leading end of the recording paper 6 even after the predetermined time, the fan control unit 46 drives the fan to rotate after the predetermined time has elapsed. Light sensor 35 in a shorter time than the time
Also drives the fan when the leading end of the recording paper 6 is detected.

Next, a specific fan control operation by the fan control units 45 and 46 of the image forming apparatus according to the present embodiment will be described with reference to FIGS. FIG. 15 shows an operation when the rotation of the fan of the fan unit 33 is started at different timings according to the horizontal / vertical installation state of the apparatus main body 1. That is, first, the installation direction of the apparatus main body 1 is determined by the installation direction determination unit 36 based on the output signal from the optical sensor 15a (step S33).

When the apparatus main body 1 is in the horizontal state,
The control unit 45 selects the horizontal fan control unit 45, receives the image forming data, and simultaneously drives the fan of the fan unit 33 by the fan drive unit 47 (step S34). On the other hand, when the apparatus main body 1 is in the vertically installed state, the vertically arranged fan control section 46 is selected by the control condition selecting section 44, and after receiving data of one page, the fan of the fan unit 33 is driven by the fan. Part 47
(Step S35).

That is, the horizontal fan control unit 45 drives the fan at a predetermined horizontal drive timing when the power is turned on, while the vertical fan control unit 46 turns the fan horizontally when the power is turned on. The fan is driven at a vertical drive timing that is later than the placement drive timing.

In the vertical position, the fan does not rotate after the power is turned on until the reception of one page of data is completed. It will rise as the temperature rises. Then, it is constantly monitored whether or not printing is in progress (step S36).
After a lapse of minutes, the rotation of the fan is stopped (step S3).
7).

FIG. 16 shows an operation in the case where the rotation of the fan of the fan unit 33 is stopped at different timings according to the horizontal / vertical installation state of the apparatus main body 1. That is, first, the installation direction of the apparatus main body 1 is determined by the installation direction determination unit 36 based on the output signal from the optical sensor 15a (step S38).

When the apparatus main body 1 is in the horizontal state,
When the horizontal fan control unit 45 is selected by the control condition selection unit 44 and printing is completed (NO in step S39), the rotation of the fan is stopped one minute after the printing is completed (step S40). ). On the other hand, when the apparatus main body 1 is in the vertical position, the vertical position fan control unit 46 is selected by the control condition selecting unit 44, and when printing is completed (NO in step S41), printing is terminated. After 2 minutes have elapsed, the rotation of the fan is stopped (step S
43).

That is, the horizontal fan control unit 45 stops the fan at a predetermined horizontal stop timing after the printing is completed, while the vertical fan control unit 46 sets the horizontal fan stop timing after the printing is completed. The fan is stopped at a later vertical stop timing.

In the case where the apparatus main body 1 is in the vertical position, the heat of the fixing unit 27 rises after printing is completed, and heat is easily accumulated in the process section. There is a risk. However, in this embodiment, when the apparatus main body 1 is in the vertical state, as described above, the rotation of the fan is maintained for a longer period after printing than in the horizontal state, thereby increasing the temperature after printing. And the effect of temperature on the process section can be suppressed.

FIG. 17 shows the operation in the case where the fan of the fan unit 33 is driven to rotate at different rotational speeds depending on the horizontal / vertical installation state of the apparatus main body 1. That is, first, the installation direction of the apparatus main body 1 is determined by the installation direction determination unit 36 based on the output signal from the optical sensor 15a (step S43).

When the apparatus main body 1 is in the horizontal state,
While the horizontal condition fan control unit 45 is selected by the control condition selection unit 44 and the fan is driven to rotate at, for example, 2000 rpm by the fan drive unit 47 (step S44), the control is performed when the apparatus main body 1 is in the vertical position. Condition selector 44
To select the vertical fan control unit 46, and the fan drive unit 47 drives the fan to rotate at, for example, 2500 rpm (step S45).

That is, the horizontal fan control unit 45 drives the fan to rotate at a predetermined horizontal rotation speed, while the vertical fan control unit 46 sets a predetermined vertical rotation speed larger than the horizontal rotation speed. The fan is driven to rotate at the required rotation speed. Accordingly, in the case of the vertical installation state, the amount of air exhausted by the fan of the fan unit 33 is increased, and the inside of the apparatus main body 1 is sufficiently ventilated. As a result, it is possible to prevent the occurrence of dew condensation and the like in the process section.

Then, it is constantly monitored whether or not printing is being performed (step S46). When the printing is completed, the rotation of the fan is stopped one minute after the printing is completed (step S47). (7) Description of Fixing Unit Control In the image forming apparatus of this embodiment, when the power is turned on, the installation direction determining unit 36 determines the output signal of the optical sensor 15a and the apparatus main body 1 is in the horizontal state. Or in the vertical position. When the apparatus main body 1 is in the horizontal state, for example, the fact is notified to the control condition selecting unit 49 of the fixing device control circuit 48, and the control condition selecting unit 49 selects the horizontal fixing device control unit 50. .

According to the control sequence, the horizontal fixing device control section 50 controls the halogen lamp 52 so that the heat roller temperature becomes the normal fixing temperature at the time of initializing, for example.
The temperature is controlled by On the other hand, when the vertical fixing device control unit 51 is selected by the control condition selecting unit 49, the vertical fixing device control unit 51 temporarily raises the heat roller temperature to a temperature higher than the normal fixing temperature at the time of initial setting, for example. After that, the halogen lamp 5
2 to control the temperature.

As a result, when the apparatus main body 1 is placed vertically,
The temperature inside the apparatus main body 1 before printing rises, and the water inside the apparatus main body 1 can be discharged to the outside of the apparatus, so that dew condensation hardly occurs in the process section and the influence of water droplets is reduced. When the recording paper 6 is ejected at the end of printing, the horizontal fixing device controller 50 stops controlling the temperature of the halogen lamp 52 and drives the heat roller and the pressure roller by the fixing device driving unit 53 to rotate. To stop. On the other hand, the vertical fixing device controller 51 stops the temperature control of the halogen lamp 52 after the recording paper 6 is discharged at the end of printing, but the rotation of the heat roller and the pressure roller by the fixing device driver 53 is stopped. Continue for a predetermined time.

As a result, the rotation of the heat roller and the pressure roller by the fixing unit driving unit 53 is maintained for a longer period of time after the printing is completed than in the case of the horizontal state, so that the operation of the fixing unit 27 is controlled and the printing is completed. Suppress the subsequent temperature rise,
The effect of temperature on the process section can be suppressed. Next, a specific fixing device control operation by the fixing device control units 50 and 51 of the image forming apparatus according to the present embodiment will be described with reference to FIGS.

FIG. 18 shows an operation when the rotation of the heat roller and the pressure roller of the fixing device 27 is started at different timings according to the horizontal / vertical state of the apparatus main body 1. That is, first, the installation direction of the apparatus main body 1 is determined by the installation direction determination unit 36 based on the output signal from the optical sensor 15a (step S48). When the apparatus main body 1 is in the horizontal state, the horizontal fixing unit control unit 50 is selected by the control condition selecting unit 49, and the heat roller and the pressure roller of the fixing unit 27 are simultaneously received with the data for image formation. Is rotationally driven by the fixing device driving section 53 (step S49).

On the other hand, when the apparatus main body 1 is in the vertical position, the control unit 51 selects the vertical fixing unit control unit 51 and receives the data of one page before the fixing unit 2
The heat roller and the pressure roller 7 are driven to rotate by the fixing device driving unit 53 (step S50). That is, while the horizontal fixing device control unit 50 drives the rollers at a predetermined horizontal driving timing when the power is turned on, the horizontal fixing device control unit 51 turns the horizontal fixing device control when the power is turned on. The fan is driven at a vertical drive timing that is later than the drive timing for the fan.

Thus, in the case of the vertical position, the fixing unit 2 is turned on after the power is turned on until the reception of one page of data is completed.
Since the roller 7 does not rotate, the temperature of the process section such as the photosensitive drum 20 easily rises as the temperature of the fixing device 27 rises. Then, it is constantly monitored whether or not printing is being performed (step S51). When printing is completed, the rotation of the rollers of the fixing device 27 is stopped (step S52).

FIG. 19 shows the operation when different temperature control is performed on the fixing device 27 in accordance with the horizontal / vertical installation state of the apparatus main body 1. That is, first, based on the output signal from the optical sensor 15a, the installation direction determining unit 3
6 to determine the installation direction of the apparatus main body 1 (step S
53). When the apparatus main body 1 is in the horizontal state, the horizontal fixing device controller 50 is selected by the control condition selecting unit 49, and the temperature is set such that the heat roller temperature immediately becomes the predetermined fixing temperature by the halogen lamp 52. Control is performed (step S54).

On the other hand, when the apparatus main body 1 is in the vertical position, the control unit 51 selects the vertical fixing device control unit 51, and the halogen lamp 52 controls the heat roller temperature to a predetermined fixing temperature. After the temperature is once increased to a higher temperature (step S55), the temperature is controlled so as to reach a predetermined fixing temperature (step S54). As a result, when the apparatus main body 1 is placed vertically, the temperature inside the apparatus main body 1 before printing rises, moisture in the apparatus main body 1 can be discharged to the outside of the apparatus, and dew condensation hardly occurs in the process section.
It is less affected by water droplets.

Then, it is constantly monitored whether or not printing is being performed (step S56), and the temperature control by the halogen lamp 52 is stopped (step S57). FIG. 20 shows an operation when the heat roller temperature control (temperature stabilization control) of the fixing device 27 is started at different timings according to the horizontal / vertical state of the apparatus main body 1. That is, first, the installation direction of the apparatus main body 1 is determined by the installation direction determination unit 36 based on the output signal from the optical sensor 15a (step S58).

When the apparatus main body 1 is in the horizontal position,
The control unit 50 selects the horizontal fixing unit control unit 50, and starts the temperature stabilization control for maintaining the heat roller temperature of the fixing unit 27 at a predetermined fixing temperature at the same time as receiving the image forming data ( Step S59). On the other hand, when the apparatus main body 1 is in the vertical position, the control unit 51 selects the vertical fixing device control unit 51, receives the data of one page, and then sets the heat roller temperature of the fixing device 27. Is started at a predetermined fixing temperature (step S60).

Thus, in the case of the vertical mounting state, the fixing device 2 is turned on after the power is turned on until the reception of one page of data is completed.
Since the temperature stabilization control of the heat roller temperature of 7 is not performed, the heat roller temperature rises above a predetermined fixing temperature, so that the water in the apparatus main body 1 can be discharged out of the apparatus. Dew condensation is less likely to occur in the process section and is less affected by water droplets.

Then, it is constantly monitored whether or not the printing is being performed (step S61). When the printing is completed, the control for stabilizing the heat roller temperature of the fixing device 27 is stopped (step S62). FIG. 21 shows the fixing device 27 at different timings depending on whether the apparatus main body 1 is placed horizontally or vertically.
The operation when the rotation of the heat roller and the pressure roller is stopped is shown. That is, first, the installation direction of the apparatus main body 1 is determined by the installation direction determining unit 36 based on the output signal from the optical sensor 15a (step S63).

When the apparatus main body 1 is in the horizontal position,
When the control unit 50 selects the horizontal fixing device control unit 50 and ends printing (NO in step S64), the rotation of the heat roller and the pressure roller of the fixing device 27 is immediately stopped (step S64). S65). On the other hand, when the apparatus main body 1 is in the vertically installed state, the control condition selecting section 49
When the vertical fixing device controller 51 is selected and printing is completed (NO in step S66), the rotation of the heat roller and the pressure roller of the fixing device 27 after about 10 seconds elapse after printing is completed. Is stopped (step S67).

That is, the fixing unit control unit 50 sets the fixing unit 27 at a predetermined horizontal stop timing after printing is completed.
While the rotation of the roller of the fixing device 27 is stopped, the fixing device control section 51 for vertical placement stops the rotation of the roller of the fixing device 27 at the stop timing for vertical placement that is later than the stop timing for horizontal placement after printing is completed. As described above, by keeping the rotation of the roller of the fixing device 27 for a longer period of time after printing than in the case of the horizontal state, it is possible to suppress a rise in temperature after printing and to suppress the influence of temperature on the process unit. It has become.

FIG. 22 shows the fixing unit 2 at different timings depending on the horizontal / vertical state of the apparatus main body 1.
7 shows an operation when the temperature control of the heat roller 7 is stopped. That is, first, the installation direction of the apparatus main body 1 is determined by the installation direction determination unit 36 based on the output signal from the optical sensor 15a (step S68). When the apparatus main body 1 is in the horizontal state, the horizontal fixing unit control unit 50 is selected by the control condition selecting unit 49, and when printing is completed (NO in step S69), the fixing unit 2 is immediately set.
7, the temperature control of the heat roller is stopped (step S7).
0).

On the other hand, when the apparatus main body 1 is in the vertical position, the control condition selecting section 49 selects the vertical fixing device control section 51 and terminates printing (N in step S71).
In the case of O determination), the temperature control of the heat roller of the fixing device 27 is stopped about 10 seconds after printing is completed (step S72). That is, the horizontal fixing device control unit 50
At a predetermined horizontal stop timing after printing, the temperature control for maintaining the heater of the fixing unit 27 at a predetermined fixing temperature is stopped at the predetermined horizontal stop timing. At a later vertical stop timing, the temperature control for maintaining the heater of the fixing unit 27 at a predetermined fixing temperature is stopped.

As described above, even according to the procedure shown in FIG. 22, by controlling the temperature of the heat roller of the fixing device 27 for a longer period after printing is completed than in the case of the horizontal state, the rise in temperature after printing is suppressed. In addition, the influence of temperature on the process section can be suppressed. As described above, according to the image forming apparatus of the present embodiment, it is possible to perform control under the control conditions corresponding to the installation direction, and the apparatus operates under the control suitable for the installation direction. With a simple configuration, a stable image forming operation that is not affected by the installation direction can be realized, and the reliability of the image forming process is greatly improved.

At this time, by performing empty control according to the installation direction of the apparatus main body 1, toner empty control independent of the installation direction becomes possible, so that stable toner empty detection / display or near empty Detection / display can be performed. In addition, by controlling the operation state of the fan unit 33 in accordance with the installation direction of the apparatus main body 1, a required air volume can be obtained at an optimum timing, so that a temperature rise or a trouble due to water vapor can be prevented. Since the fixing device 27 can also be controlled in accordance with the installation direction of the apparatus main body 1, a necessary amount of heat can be obtained at an optimum timing, and unnecessary heat generation can be suppressed. In addition, condensation due to water vapor can be prevented.

In the above-described embodiment, only the case where the apparatus main body 1 operates in the two installation directions of the horizontal installation state and the vertical installation state has been described. However, the present invention is not limited to this. The present invention is also applied to an image forming apparatus that operates in a direction other than the above or in a state where the image forming apparatus is installed in two or more directions, and the same operation and effect as the above embodiment can be obtained. However,
In this case, the control unit is provided with a control sequence unit that performs control under control conditions corresponding to the direction.

The control operations described with reference to FIGS. 11 to 22 may be performed separately or in an appropriate combination.

[0163]

As described above in detail, according to the image forming apparatus of the present invention, when the apparatus main body is in the vertical state, the recording paper is moved between the horizontal stack section and the vertical stacker member. Since the stacking space is formed, the recording paper can be reliably stacked in a compact space, contributing to space saving, and making use of the advantage of the vertical arrangement (claim 1).

At this time, recording is performed by providing a lower space in the horizontal stack portion (claim 2) or by providing a pressing member for pressing the recording paper toward the horizontal stack portion (claim 3). The sheets can be reliably stacked in the page order, and it is not necessary to rearrange the order of the recording sheets after the completion of the image formation. Further, by forming the vertical stacker member in a U-shape, the recording paper after image formation can be easily taken out regardless of the size of the recording paper, and the workability can be greatly improved. 4).

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view schematically showing a structure of an image forming apparatus as one embodiment of the present invention.

FIG. 2 is a block diagram functionally showing a configuration of a control system of the image forming apparatus as one embodiment of the present invention.

FIG. 3 is a block diagram illustrating a basic configuration of a control system in the image forming apparatus according to the embodiment.

FIG. 4 is an enlarged perspective view showing a claw portion formed on the paper cassette of the present embodiment.

FIG. 5 is a side view illustrating a schematic structure of an installation direction detection unit according to the present embodiment.

FIG. 6 is a perspective view illustrating a horizontal installation state of the image forming apparatus according to the present exemplary embodiment.

FIG. 7 is a perspective view illustrating a vertically installed state of the image forming apparatus according to the present exemplary embodiment.

FIG. 8 is a longitudinal sectional view showing a state of the developing device in a horizontal installation state.

FIG. 9 is a longitudinal sectional view showing a state of the developing device in a vertically installed state.

FIG. 10 is a diagram for explaining a toner empty detection operation in the present embodiment.

FIG. 11 is a flowchart illustrating a toner empty control operation according to the present embodiment.

FIG. 12 is a flowchart illustrating a toner empty control operation according to the present embodiment.

FIG. 13 is a flowchart illustrating a toner empty control operation according to the present exemplary embodiment.

FIG. 14 is a flowchart illustrating a toner empty control operation according to the present embodiment.

FIG. 15 is a flowchart illustrating a fan control operation according to the present embodiment.

FIG. 16 is a flowchart illustrating a fan control operation according to the present embodiment.

FIG. 17 is a flowchart illustrating a fan control operation according to the present embodiment.

FIG. 18 is a flowchart illustrating a fixing device control operation according to the present embodiment.

FIG. 19 is a flowchart for explaining a fixing device control operation of the present embodiment.

FIG. 20 is a flowchart for describing a fixing device control operation of the present embodiment.

FIG. 21 is a flowchart illustrating a fixing device control operation according to the present embodiment.

FIG. 22 is a flowchart for describing a fixing device control operation of the present embodiment.

FIG. 23 is a cross-sectional view of a main part schematically showing a conventional toner empty detection mechanism.

FIG. 24 is a graph illustrating the operation of a comparator in a conventional toner empty detection mechanism.

FIG. 25 is a graph showing output characteristics of a general magnetic permeability sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Installation direction detection part 3 Control part 4 Control sequence part 5 Control condition selection part 6 Recording paper 7 Conveying path 8 Pressing member 9 Water absorption sheet 10 Paper cassette 10a Side plate 10b Claw part 11 Pick roller 12 Registration roller 13 Discharge roller Reference Signs List 14 Stacker (horizontal stack unit) 14A Lower space 15 Printed board 15a Optical sensor (installation direction detector) 15b Rotary shaft 15c Blocking piece (shutter) 15d Light receiving element 15d Photocoupler (optical sensor) 15A Connector 16 Power supply 17 Interface connector 17a External cable 18 Option board 20 Photosensitive drum (process section) 21 Pre-charger 22 Optical unit 23 Developing device 23a Case 230 Developing room 230-1 Partition member 230-2 Bottom 230-3 Projection 230-4 231 Toner hopper 232 Supply roller (agitator) 234 Doctor blade 235 Toner supply path 24 Developing roller 240 Magnet 241 Sleeve 25 Toner cartridge 26 Transfer unit 27 Fixing unit 28 Dispersing member 29 Toner sensor (toner detecting unit) 30 Paper guide 30a Paper contact member Reference Signs List 31 Stacker member for vertical placement 31A Recess 32 Stand 33 Fan unit 34 Vent hole 35 Optical sensor (recording paper passage detecting section) 36 Installation direction determining section 37 Empty control circuit (Control section) 38 Control condition selecting section 39 Toner empty for horizontal placing Status determination unit 40 Horizontal toner empty status determination unit 41 Output unit 42 Empty status display unit 43 Fan control circuit (control unit) 44 Control condition selection unit 45 Horizontal fan control unit 46 Horizontal fan control Control unit 47 Fan driving unit 48 Fixing unit control circuit (control unit) 49 Control condition selecting unit 50 Horizontal fixing unit control unit 51 Horizontal fixing unit control unit 52 Fixing unit driving unit 53 Halogen lamp (heater) 60 Developer

Continuing from the front page (72) Inventor Shinzo Tanaka 1015 Uedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Nobuyuki Tanaka 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture F Fujitsu Limited Terms (reference) 2C061 AP04 BB01 BB05 BB35 CC07 CC09 CE03 CF07 CF14 2H071 AA27 AA35 AA39 DA24 EA04 3F054 AA01 AC01 BA02 BF07 BF09 DA12

Claims (4)

[Claims] 1. An image forming apparatus operable in any of a horizontal installation state in which the apparatus main body is installed in a horizontal direction and a vertical installation state in which the apparatus main body is installed in a vertical direction, When the apparatus main body is in the horizontal state, a horizontal stack portion capable of storing the recording paper after image formation discharged from the apparatus main body with the image forming surface downward is provided on the upper surface of the apparatus main body. When the apparatus main body is in the vertical position, a vertical stacker member attached to the apparatus main body opposite to the horizontal stack portion is detachably provided, and An image forming apparatus, wherein a space for stacking recording paper is formed between a stack portion and the vertical stacker member. 2. A structure in which a discharge port for discharging the recording paper from the apparatus main body to the stacking space is arranged at a lower side when the apparatus main body is in the vertically placed state, The image forming apparatus according to claim 1, wherein a lower space extending below the sheet discharge port is formed below the stacking portion. 3. The stacker member for vertical placement, wherein a pressing member capable of pressing the recording paper discharged from the paper discharge port toward the stacking section for horizontal placement is attached to the stacker member for vertical placement. Item 3. The image forming apparatus according to Item 2. 4. The image forming apparatus according to claim 3, wherein said vertical stacker member is formed in a U-shape.