JP3226196B2 - Electrophotographic printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic printer.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic printer, a charged photosensitive drum is irradiated by a light source to form an electrostatic latent image on the surface thereof, and toner is attached to the electrostatic latent image to form a toner image. Thereafter, the toner image is transferred to a print medium to obtain an image. To this end, there has been provided a photosensitive drum unit in which a photosensitive drum and a developing device disposed opposite to the photosensitive drum are integrated.

In the electrophotographic printer having the above-described configuration, it is possible to determine whether or not the photosensitive drum unit is mounted. Usually, when a photosensitive drum unit is mounted, a print medium accommodated in a paper cassette or the like is conveyed to a lower end portion of the photosensitive drum unit by a feed roller or the like,
The print medium that has reached the lower end is further transported by the photosensitive drum unit to perform printing.

On the other hand, when the photosensitive drum unit is not mounted, the print medium that has reached the position corresponding to the lower end of the photosensitive drum unit is not further conveyed and does not reach the paper detection sensor. As a result, an alarm indicating a paper jam is displayed.

[0005]

However, in the conventional method for detecting a photosensitive drum unit in an electrophotographic printer, if printing is started and the print medium is not conveyed to the lower end of the photosensitive drum unit, is the photosensitive drum unit mounted? Not only is it not possible to determine whether the sheet is jammed, but also if the photosensitive drum unit is not mounted, a paper jam occurs.

As a result, the printing medium that caused the paper jam is removed from the electrophotographic printer, and printing can be performed only after the photosensitive drum unit is mounted. The work to do is cumbersome. The present invention solves the problem of the conventional electrophotographic printer, and can determine whether or not the photosensitive drum unit is mounted without performing printing, and a paper jam occurs at the time of the determination. It is an object of the present invention to provide an electrophotographic printer which does not have a troublesome operation for actually performing printing.

[0007]

For this purpose, in the electrophotographic printer of the present invention, it is possible to mount a photosensitive drum unit comprising at least a photosensitive drum and a developing device arranged to face the photosensitive drum. And
The stirring bar is disposed in the photosensitive drum unit, and when the photosensitive drum unit is mounted, a stirring bar whose rotation is started along with the start of warming-up, and the rotation of the stirring bar is detected, and the time during which the stirring bar is on is described above. A sensor that varies depending on the toner load received by the stirring bar, and during warm-up, when the rotation of the stirring bar is not detected, it is determined that the photosensitive drum unit is not mounted, and when the rotation of the stirring bar is detected, A control unit that determines that the drum unit is mounted and identifies a toner full state and a toner low state based on the length of time the sensor is on.

[0008]

[0009]

According to the present invention, as described above, in an electrophotographic printer, a photosensitive drum unit including at least a photosensitive drum and a developing device disposed to face the photosensitive drum can be mounted. When the photosensitive drum unit is mounted in the photosensitive drum unit and the photosensitive drum unit is mounted, rotation of the stirring rod is started along with the start of warming-up, and the rotation of the stirring rod is detected, and the time during which the stirring rod is on is detected. When the rotation of the stirring bar is detected when the rotation of the stirring bar is not detected and the rotation of the stirring bar is detected when the rotation of the stirring bar is not detected during warm-up, And a controller for determining whether the photosensitive drum unit is mounted on the printer and discriminating between a toner full state and a toner low state based on the length of time the sensor is on.

In this case, if the rotation of the stirring rod is started in response to the start of the warm-up, it can be determined whether or not the photosensitive drum unit is mounted without actually performing printing.

If the sensor is on for a long time, the load on the toner is large, and it is determined that the toner is full. On the other hand, if the time during which the sensor is turned on is short, the load due to the toner is small and it is determined that the toner is in the low state.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 is a sectional view of an electrophotographic printer according to the first embodiment of the present invention, and FIG.
FIG. 4 is a front view of a stirring rod according to the first embodiment of the present invention, and FIG. 5 is a left side view of the stirring rod according to the first embodiment of the present invention. 6 is a right side view of the stirring rod according to the first embodiment of the present invention, FIG.
FIG. 8 is a front view of the gear according to the first embodiment of the present invention, FIG. 8 is a right side view of the gear according to the first embodiment of the present invention, and FIG. FIG.

In FIG. 2, reference numeral 11 denotes a photosensitive drum unit, and 12 denotes a photosensitive drum which is housed in the photosensitive drum unit 11 and whose surface is uniformly and uniformly charged by a charging device (not shown) in the photosensitive drum unit 11. The photosensitive drum 12 is exposed by an exposure device (not shown), and an electrostatic latent image is formed on the surface. Reference numeral 13 denotes a developing roller housed in the photosensitive drum unit 11 and arranged to face the photosensitive drum 12, and develops the electrostatic latent image into a toner image. Reference numeral 14 denotes a transfer roller disposed to face the photosensitive drum 12, and transfers the toner image to a print medium (not shown).

Reference numeral 16 denotes the photosensitive drum unit 11
A toner cartridge 17 is provided in the photosensitive drum unit 11 and supplies toner to the photosensitive drum unit 11. A stirring rod 17 is housed in the photosensitive drum unit 11 and rotated clockwise about the shaft 26 in the figure. The stirring rod 1
7 stirs the toner supplied from the toner cartridge 16 to make it uniform, and conveys the toner to the toner supply roller 18.

Reference numeral 21 denotes a lever provided outside the photosensitive drum unit 11 so as to correspond to the stirring rod 17. The lever 21 includes two arms 23 and 24, has a substantially “L” shape, and is supported so as to be swingable about a shaft 22. A magnet 25 is provided at the tip of the arm 23, while the stirring rod 1
The magnet 27 is disposed at the tip of the seventh.

Therefore, when the stirring rod 17 rotates and the magnet 27 passes near the lever 21, the lever 21
The magnet 25 fixed to the arm 23 is attracted, and as a result, the lever 21 swings. By the way, a passage type toner sensor 29 is disposed on the frame of the electrophotographic printer in the vicinity of the other arm 24 of the lever 21. Therefore, when the magnets 25 and 27 are attracted to each other and the lever 21 swings, the arm 24 is separated from the toner sensor 29 and the toner sensor 29 is turned on.
Subsequently, after the stirring rod 17 has passed near the lever 21, the magnet 25 and the magnet 27 are released and the lever 21 is released.
Swings, the arm 24 moves the toner sensor 2
9, the toner sensor 29 is turned off.

3 to 9, reference numeral 11 denotes a photosensitive drum unit, reference numeral 17 denotes a swinging stirrer, and reference numeral 21 denotes a photosensitive drum unit.
Is a lever, 25 and 27 are magnets, and 29 is a toner sensor. As shown in FIG.
6, an arm 31 fixed to the shaft 26, and a bar 32 which connects the distal end of the arm 31 and is arranged in the width direction of the print medium 34. An iron core 33 as a weight is embedded in the bar 32. AR is a medium area set in the width direction of the print medium 34.

A gear 36 is provided to apply a rotational force to the shaft 26. 7 and 8, a projection 39 is formed inside the gear 36, while the shaft 26 is engaged with the projection 39 inside the gear 36 as shown in FIGS. A projection 38 is formed. Therefore, by rotating the gear 36, the two projections 38 and 39 are engaged, and the stirring bar 17 can be rotated. After reaching the top dead center, the stirring rod 17 can rotate by 180 ° by its own weight.

Next, the on / off operation of the toner sensor 29 will be described. FIG. 10 is an explanatory diagram of the operation of the toner sensor according to the first embodiment of the present invention. In the figure, 17 is a stirring rod, 21 is a lever, 22 is a shaft, 2
Reference numerals 3 and 24 denote arms, 25 and 27 denote magnets, and 29 denotes a toner sensor. When a stepping motor (not shown) is driven to operate the photosensitive drum unit 11 (FIG. 3), the gear 36 is rotated, and the projection 38 (FIG. 7) of the stirring rod 17 is rotated by the projection 39 formed on the gear 36. , And the stirring rod 17 is rotated in the arrow X direction.

When the stirring rod 17 passes through the position a, the magnets 25 and 27 are attracted to each other, and the lever 21 swings and moves to the position A. As a result, the toner sensor 29 is turned on. become. When the stirring rod 17 is further rotated and moves to the position b, the magnets 25, 27
Is released, the lever 21 swings and moves to the position B, and as a result, the toner sensor 29 is turned off.

Next, the detection operation of the photosensitive drum unit 11 will be described. FIG. 1 is a block diagram of the electrophotographic printer according to the first embodiment of the present invention, and FIG. 16 is a flowchart showing the operation of the electrophotographic printer according to the first embodiment of the present invention. In FIG. 1, reference numeral 41 denotes a control unit for controlling the entire electrophotographic printer, 42 denotes a stepping motor for operating the electrophotographic printer, and 11 denotes a photosensitive drum unit. The photosensitive drum unit 11 has a gear 36 and a stirring rod 17.

Reference numeral 21 denotes a lever; 29, a toner sensor; and 43, an LED for displaying an alarm when the photosensitive drum unit 11 is not mounted. The LE
An LCD can be used instead of D43. In the electrophotographic printer having the above configuration, when the power is turned on or the cover of the electrophotographic printer is closed, warm-up starts, and the stepping motor 42 for operating the electrophotographic printer starts rotating. At this time, the toner sensor 2 is not turned on until the time (hereinafter, referred to as “two cycles”) in which the photosensitive drum 12 (FIG. 2) rotates twice.
9 detects the rotation of the stirring rod 17 and determines whether or not it is turned on, and determines whether or not the photosensitive drum unit 11 is mounted.

That is, when the photosensitive drum unit 11 is mounted, the gear 36 rotates with the rotation of the stepping motor 42, and the stirring bar 17 is rotated. Therefore, with the rotation of the stirring rod 17, the lever 21
Swings, and the toner sensor 29 is turned on. As described above, it is possible to determine whether or not the photosensitive drum unit 11 is mounted without actually performing printing before the warm-up is completed.

When the photosensitive drum unit 11 is not mounted, the lever 21 is located at the position B even if the stepping motor 42 is rotated. Therefore,
The toner sensor 29 is not turned on and the LED 43
Performs an alarm display. As described above, since it is possible to determine whether the photosensitive drum unit 11 is mounted without starting printing, paper jam does not occur when the determination is made. Therefore, the work for actually performing printing is facilitated. Step S1 Warm-up of the electrophotographic printer is started. Step S2: The stepping motor 42 for driving the photosensitive drum unit 11 is rotated. Step S3: It is determined whether the toner sensor 29 has been turned on. When it is turned on, the process proceeds to step S4, and when it is not turned on, the process proceeds to step S5. Step S4: Terminate the warm-up of the electrophotographic printer. Since the toner sensor 29 is not turned on during two cycles of step S52, it is determined that the photosensitive drum unit 11 is not mounted (not mounted), and an alarm is displayed by the LED 43.

FIG. 17 is a time chart of the toner sensor when the photosensitive drum unit according to the first embodiment of the present invention is mounted, and FIG. 18 is a case where the photosensitive drum unit according to the first embodiment of the present invention is not mounted. 6 is a time chart of the toner sensor of FIG. As shown in FIG. 17, when the photosensitive drum unit 11 (FIG. 2) is mounted, the toner sensor 29 is turned on every time the photosensitive drum 12 makes one rotation (hereinafter, referred to as "one cycle").
On the other hand, when the photosensitive drum unit 11 is not mounted, the toner sensor 29 is not turned on during two cycles even if the warm-up is started.

Next, a second embodiment of the present invention will be described. In this case, it is possible not only to determine whether the photosensitive drum unit 11 is mounted, but also to determine whether a sufficient amount of toner is stored in the photosensitive drum unit 11. A state in which a sufficient amount of toner capable of satisfying print density, print quality, and the like is stored in the photosensitive drum unit 11 is referred to as a toner full state, and a sufficient amount of toner is stored in the photosensitive drum unit 11. The state where the operation is not performed is referred to as a toner low state.

FIG. 11 is a first view of the toner full state according to the second embodiment of the present invention, FIG. 12 is a second view of the toner full state according to the second embodiment of the present invention, and FIG. FIG. 14 is a first view of the toner low state in the second embodiment of the present invention, and FIG. 15 is a second view of the toner low state in the second embodiment of the present invention. FIG.

That is, in the toner full state, as shown in FIG. 11, a sufficient amount of toner is stored in the photosensitive drum unit 11 (FIG. 3). Then, the projection 38 of the stirring rod 17 is pushed by the projection 39 of the gear 36 rotated at a constant speed, and the stirring rod 17 is rotated in the direction of the arrow X. At this time, the lever 21 is moved to the position A, and the toner sensor 29 is turned on. Then, as shown in FIG. 12, when the stirring rod 17 is further rotated, the lever 21 is moved to the position B, and as a result, the toner sensor 29 is turned off.

Next, when the stirring rod 17 reaches the top dead center as shown in FIG.
Rotated in the direction. At this time, the lever 21 is also at the position B, and the toner sensor 29 is off. When the stirring rod 17 is rotated by its own weight, the rotation is stopped as shown in FIG. 13 by the load of the toner. In this case, since the stirring rod 17 is rotated before the gear 36 (FIG. 7), the projection 38 of the stirring rod 17 is
9, there is no force to rotate the stirring rod 17 by the gear 36. During this time, the lever 21 is also at the position B, and the toner sensor 29
Is off. When the projection 39 catches up with the projection 38, the stirring rod 17 is rotated again by the gear 36.

On the other hand, in the toner low state, FIG.
As shown in (1), a sufficient amount of toner is not stored in the photosensitive drum unit 11 (FIG. 1). In this case, when the stirring rod 17 reaches the top dead center, the stirring rod 17 is rotated by its own weight in the same manner as in FIG. 12, but since the amount of toner is small, the stirring rod 17 reaches the vicinity of the bottom dead point as it is. As a result, the magnets 25 and 27 are attracted to each other, the lever 21 swings and moves to the position A, and the toner sensor 29 is turned on. Then, the projection 39 of the gear 36 is directly connected to the stirring rod 17.
And waits until catching up with the projection 38 of.

When the projection 39 of the gear 36 catches up with the projection 38 of the stirring rod 17 as shown in FIG.
The protrusion 38 of the stirring rod 17 is pressed by the protrusion 39 of No. 6,
The stirring rod 17 starts rotating again. Meanwhile, the lever 21 is at the position A, and the toner sensor 29 is off. FIG.
FIG. 20 is a time chart of the toner sensor in the toner full state according to the second embodiment of the present invention, and FIG. 20 is a time chart of the toner sensor in the toner low state in the second embodiment of the present invention.

As shown in the figure, in the toner full state, the time during which the toner sensor 29 is on is shortened by the amount of time that the stirring rod 17 is placed in the state shown in FIG. On the other hand, in the toner low state, the stirring rod 17 reaches at a stroke from the top dead center to the vicinity of the bottom dead center, so that as shown in FIG. , The time during which the toner sensor 29 is on is also prolonged.

Therefore, the time during which the toner sensor 29 is on is monitored, the time is counted by a counter or the like in the control section 41 (FIG. 1), and the measured time is compared with a reference value to make toner full. The state is distinguished from the toner low state, and the identification result is displayed on the LED 43.
Therefore, the operator can easily replenish the toner according to the display of the LED 43.

The present invention is not limited to the above embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0035]

As described above in detail, according to the present invention, in an electrophotographic printer, it is possible to mount a photosensitive drum unit including at least a photosensitive drum and a developing device arranged to face the photosensitive drum. It is.

When the photosensitive drum unit is mounted in the photosensitive drum unit and the photosensitive drum unit is mounted, the rotation of the stirring rod is started when the warming-up is started, and the rotation of the stirring rod is detected. And a sensor that changes the time during which the stirring bar receives the toner load, and determines that the photosensitive drum unit is not mounted when the rotation of the stirring bar is not detected during warm-up, and detects the rotation of the stirring bar. When it is determined that the photosensitive drum unit is mounted,
A control unit for distinguishing between a toner full state and a toner low state based on the length of time the sensor is on. In this case, it is determined whether the rotation of the stirring bar is detected by the sensor during the warm-up. Therefore, by the time the warm-up is completed, it can be determined whether or not the photosensitive drum unit is mounted without actually performing printing. As a result, a paper jam due to the absence of the photosensitive drum unit does not occur, so that the work for actually performing printing can be simplified.

If the sensor is on for a long time, the load on the toner is large, and it is determined that the toner is full. On the other hand, if the time during which the sensor is turned on is short, the load due to the toner is small and it is determined that the toner is in the low state. Therefore, the amount of the toner stored in the photosensitive drum unit can be recognized, so that the toner can be easily supplied.

[Brief description of the drawings]

FIG. 1 is a block diagram of an electrophotographic printer according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the electrophotographic printer according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating an arrangement state of a toner sensor according to the first embodiment of the present invention.

FIG. 4 is a front view of a stirring rod according to the first embodiment of the present invention.

FIG. 5 is a left side view of the stirring rod according to the first embodiment of the present invention.

FIG. 6 is a right side view of the stirring rod according to the first embodiment of the present invention.

FIG. 7 is a front view of the gear according to the first embodiment of the present invention.

FIG. 8 is a right side view of the gear according to the first embodiment of the present invention.

FIG. 9 is a diagram showing an engagement state of a projection in the first embodiment of the present invention.

FIG. 10 is a diagram illustrating the operation of the toner sensor according to the first embodiment of the present invention.

FIG. 11 is a first diagram illustrating a toner full state according to a second embodiment of the present invention.

FIG. 12 is a second diagram of the toner full state according to the second embodiment of the present invention.

FIG. 13 is a third diagram illustrating the toner full state according to the second embodiment of the present invention.

FIG. 14 is a first diagram illustrating a toner low state according to the second embodiment of the present invention.

FIG. 15 is a second diagram of the toner low state according to the second embodiment of the present invention.

FIG. 16 is a flowchart illustrating an operation of the electrophotographic printer according to the first embodiment of the present invention.

FIG. 17 is a time chart of the toner sensor when the photosensitive drum unit according to the first embodiment of the present invention is mounted.

FIG. 18 is a time chart of the toner sensor when the photosensitive drum unit according to the first embodiment of the present invention is not mounted.

FIG. 19 is a time chart of the toner sensor in a toner full state according to the second embodiment of the present invention.

FIG. 20 is a time chart of the toner sensor in a toner low state according to the second embodiment of the present invention.

[Explanation of symbols]

 11 Photosensitive Drum Unit 12 Photosensitive Drum 17 Stirring Bar 29 Toner Sensor

Continued on the front page (72) Inventor Takakazu Hiruta 1-1, Tateda, Shono-ji, Fukushima, Fukushima Prefecture Inside Oki Data Systems Co., Ltd. (72) Masatoshi Nakamura 1-1, Tateda, Shono, Fukushima-shi, Fukushima Japan (72) Inventor Nagakatsu Sudo 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (56) References JP-A-5-111610 (JP, A) JP-A Heisei JP-A-6-118793 (JP, A) JP-A-6-130817 (JP, A) JP-A-3-138672 (JP, A) JP-A-4-188172 (JP, A) JP-A-4-38875 (JP, A) A) JP-A-5-197281 (JP, A) JP-A-7-98538 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/00 G03G 15/08 G03G 21 / 00-21/04 G03G 21/16-21/18

Claims (1)

(57) [Claims] 1. A least a photosensitive drum, and an electrophotographic printer that allows mounting of the photosensitive drum unit comprising a photosensitive drum and is opposed to a developing device which is disposed, is disposed on (a) the photosensitive inside drum unit, photosensitive Dora
Warm up when the unit is installed
A stirring bar rotation is started with the start of, (b) detecting the rotation of the stirring拌棒, a sensor time is on varies depending on the load of the toner the stir bar is subjected, (c) During the warm-up, it is determined that the photosensitive drum unit is not mounted when the rotation of the stirring bar is not detected, and it is determined that the photosensitive drum unit is mounted when the rotation of the stirring bar is detected,
An electrophotographic printer, comprising: a control unit for distinguishing between a toner full state and a toner low state based on the length of time the sensor is on.