JP2001201898A - Image recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image recording apparatus having a function by which toner-end is detected surely. SOLUTION: In the image recording apparatus of an electrophotographic system, a photosensor 5 is disposed so as to be opposed to the surface of a photoreceptor 1 at a position, which is the center part of the image-recording area of the photoreceptor 1 and is between a developing roller 4a and a transfer roller 7. Then, toner is stuck to the photoreceptor 1 after applying bias to the developing roller 4a before and after image-recording operation, and the existence of the toner on the surface of the photoreceptor 1 is detected by the photosensor 5, and the photoreceptor 1 is rotated in reverse, after detection and the bias having reverse polarity is applied to the developing roller 4a, so that the toner on the surface of the photoreceptor 1 is returned to the developing roller 4a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus for recording an image by an electrophotographic method.

[0002]

2. Description of the Related Art An electrophotographic image recording apparatus is provided with a mechanism for detecting the remaining amount of toner and notifying a user when the remaining amount of toner is low.

As a conventional means for detecting the remaining amount of toner, there is, for example, a toner remaining amount detecting mechanism described in Japanese Patent Application Laid-Open No. 9-236981. It describes a technique for detecting the remaining amount of fuel.

[0004]

However, in the conventional image recording apparatus, even if the remaining amount of toner in the toner storage unit is reduced, the toner remains in the print process unit itself. Can continuously record images, and when notified that the toner level is low, replacing the unit immediately means that more new toner is discarded without being used for image recording. Leads to

In the case of an electrophotographic facsimile apparatus, for example, when a large amount of image data is received in a state where the amount of remaining toner in the toner container is small,
The image recording is continued even if the toner storage section becomes the toner end during the recording of the image and the image recording becomes impossible,
When the image data is erased after the image recording is completed, the information may not be transmitted reliably.

An object of the present invention is to solve such a problem and to provide an image recording apparatus having a function of reliably detecting toner end.

[0007]

In order to achieve the above object, the present invention provides an image carrier, charging means for charging the rotating image carrier, and forming an electrostatic latent image on the image carrier. An image forming unit, a developing unit including a toner storage unit for storing new toner and a developing unit for applying toner to an electrostatic latent image formed on the image carrier, and recording the toner on the image carrier. In an image recording apparatus having a transfer unit for transferring to a paper, a toner unit is disposed between the developing unit and the transfer unit so as to face a toner image recording area surface of the image carrier and detects toner on the surface of the image carrier. A toner detecting unit that determines that the amount of adhered toner is smaller than a reference value or that toner is not adhered based on the detection result of the toner detecting unit. And an electric field is formed between the developing means and the image carrier so that the toner can be moved from the developing means to the image carrier. The toner on the surface of the image carrier when rotated is detected by the toner detecting means. With this configuration, the presence or absence of the toner to be supplied to the developing unit is detected by detecting the toner on the surface of the image carrier, so that a reliable toner end can be detected, and the toner in the toner storage unit to be supplied to the developing unit can be detected. Thus, the amount of toner remaining without being used can be reduced.

Further, the invention is characterized in that when the toner detecting means detects the toner on the surface of the image carrier, the direction of the electric field between the developing means and the image carrier is switched so as to change the direction of the electric field on the image carrier. The image carrier is rotated in the reverse direction with the toner being movable to the developing device, and the toner on the image carrier is returned to the developing device.
With this configuration, the toner on the image carrier can be returned to the developing unit, and the paper dust attached to the cleaning blade can be removed.

Further, the present invention is characterized in that the toner detecting means is arranged at the center of the toner image recording area of the image carrier. With this configuration, since the toner is removed from the central portion of the image carrier, it is possible to accurately detect whether or not the image can be recorded by arranging the toner detecting means in this portion.

Further, the present invention is characterized in that the operation of detecting the toner end is performed before and after the end of recording on the recording paper, and when the toner end is detected, the recording is disabled. With this configuration, by performing the toner end detection operation before the start of recording and after the end of the recording, it is possible to confirm whether the recording is in a recordable state and whether the recording operation has been performed reliably. .

Further, the present invention is characterized in that when a toner end is detected after the end of recording on the recording paper, it is determined that a recording error has occurred, and a signal for requesting re-output is output. With this configuration, it is possible to cause the other party that has transmitted the image data to hold the data, and to obtain the data again from the other party after the toner is supplied.

[0012]

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

FIG. 1 is an explanatory view showing the structure of a main part of an apparatus according to an embodiment of the present invention. Reference numeral 1 denotes a photosensitive member serving as an image carrier, reference numeral 2 denotes a charging roller, reference numeral 3 denotes an optical writing device, and reference numeral 4 denotes Photoconductor 1
Roller 4a for supplying toner to the toner, toner replenishing unit 4b for supplying toner to developing roller 4a, toner replenishing unit 4b
A developing device provided with a toner storage unit 4c for storing new toner to be supplied to the developing unit 5; a reflection type photosensor; 6 a determination unit for determining the toner end in the toner storage unit 4c based on the output result of the photosensor 5 And 7, a transfer roller; and 8, a cleaning blade.

A charging roller 2, a developing roller 4a, a transfer roller 7, and a cleaning blade 8 are sequentially contacted with the photosensitive member 1 in the normal rotation direction, and the photosensitive member 1 is located between the charging roller 2 and the developing roller 4a. The area is irradiated with a light beam output from the optical writing device 3, and a photosensor 5 is provided so as to face the surface of the photoconductor 1 between the developing roller 4 a and the transfer roller 7.

The surface of the photoreceptor 1 rotating forward is uniformly charged by the charging roller 2. By irradiating the charged area with the beam light, an electrostatic latent image is formed on the surface of the photoconductor 1. When the electrostatic latent image passes through the developing roller 4a, toner is supplied from the developing roller 4a to form a toner image. Then, the toner image is transferred to the recording paper by the transfer roller 7, and the remaining toner and paper dust without being recorded are collected by the cleaning blade 8 to clean the photoconductor 1.

FIG. 2 is a perspective view of a part of the configuration of the apparatus shown in FIG. 1, 9 is a laser diode for emitting a light beam according to image information, and 10 is a parallel light beam emitted from the laser diode 9. A collimator lens for shaping into light, 11 is a cylindrical lens for correcting surface tilt of the polygon mirror 12, and 12 is a cylindrical lens 11
A polygon mirror 13 for deflecting the light beam passing through the main scanning direction, a fθ lens 13 for adjusting a beam spot formed on the surface of the photoreceptor 1 to have a predetermined shape,
14 is a reflection mirror for deflecting the light beam passing through the fθ lens 13 to the photoreceptor 1, 15 is a synchronization sensor for synchronizing the light beam so as to always take a fixed start position, and 16 is a beam incident on the synchronization sensor 15. 5 shows a synchronous lens that adjusts a spot to have a predetermined shape. Optical writing device 3
Is provided with a laser diode 9, a collimator lens 10, a cylindrical lens 11, a polygon mirror 12, an fθ lens 13, a reflection mirror 14, a synchronization sensor 15, and a synchronization lens 16. The photosensor 5 is installed so as to face the center of the photoconductor 1 in the main scanning direction, and emits light toward the photoconductor 1 and emits light toward the photoconductor 1.
The reflected light is received from the CPU, and data on the amount of reflected light is sent to the determination unit 6.

Next, the operation of detecting the toner end will be described. The toner end detecting operation is performed when the photosensitive member 1 before the image recording operation is in a state where the charge is removed. Normally, the potential of the photoconductor 1 before the image recording operation is 0 to -100V. Therefore, a normal bias (-400 V) is applied to the developing roller 4a.
Is applied, an electric field from the photoconductor 1 to the developing roller 4a is formed, so that the toner on the developing roller 4a having a negative charge easily adheres to the photoconductor 1. By rotating the photoconductor 1 forward in this state, the toner adheres to the photoconductor 1 in a belt shape. On the other hand, the amount of reflected light received by the photosensor 5 is small if toner is present on the photoconductor 1, and the amount of reflected light is small.
If there is no toner above, the amount of reflected light will be large. Therefore, if the amount of reflected light is small, it is possible to determine that toner is present in the toner container 4c, and if the amount of reflected light is large, it can be determined that the remaining amount of toner in the toner container 4c is considerably small or has disappeared.

When the amount of reflected light detected by the photo sensor 5 is higher than a preset reference value, the judging section 6 judges that the toner is out and outputs a signal to that effect. After confirming whether or not the toner has run out, a reverse bias (+250 V) is applied to the developing roller 4a to switch the direction of the electric field, and the photosensitive member 1 is rotated in the reverse direction, so that the photosensitive member 1 has a negative charge. The toner is returned to the developing roller 4a again. When the toner adhering to the photoconductor 1 reaches the contact portion between the transfer roller 7 and the photoconductor 1 when it is confirmed whether or not the toner end is reached,
By applying a bias to the transfer roller 7,
, The toner may not be transferred to the transfer roller 7.

The above-described toner end detection operation may be performed after the end of image recording. That is, when the toner end is detected before image recording, the toner container 4
c, the image recording is difficult because there is no toner, and the recording is disabled. If the toner end is detected after the image recording is completed, it is determined that a recording error has occurred, a re-output request signal is output, and the apparatus is in a recording disabled state. And For example, if the toner end was not reached before the recording but the toner end was reached at the end of the recording, an abnormal image such that the toner is partially missing is output. A signal for a re-output request is sent to the terminal on the side to hold the normal image so that it can be output again. Then, at the transmission destination of the image data that has received the signal of the re-output request, loss of the data can be prevented by holding the image data based on the request. In the case where the image data is temporarily stored in the memory and the function of deleting the image data from the memory at the end of recording is provided, when the toner end is confirmed, the image data is deleted from the memory. Alternatively, the image data may be held without being stored, and after the toner is supplied, the image data may be read from the memory and the image may be recorded again.

According to the above-described embodiment, the toner end can be reliably detected with a simple configuration in which the photo sensor 5 is disposed to face the central portion of the photoreceptor 1. Further, when the toner end is detected, the toner is once applied on the photoconductor, but the toner is returned to the developing roller 4a by reversing the photoconductor 1, so that the toner is transferred to the transfer roller 4a. 7 is not stained, and the toner consumption can be reduced. At this time, paper dust and the like adhering near the tip of the cleaning blade 8 can be removed.

Further, in a normal recording operation, the toner tends to be lost from almost the center of the recording range, so that the developing roller 4a
In the toner supply unit 4b (not shown) of the developing device that directly supplies the toner to the toner, the toner tends to remain at both ends rather than at the center. Therefore, when the photo sensors 5 are arranged at both ends of the recording range, when the toner end is detected, the toner is already exhausted at the toner replenishing portion 4b corresponding to the central portion of the developing roller 4a. Even if an image in which only both ends of the recording paper are printed is recorded, the apparatus may not be able to determine that the output is abnormal. Therefore, by setting the photo sensor 5 at substantially the center of the recording range as in the present embodiment, it is possible to reliably determine whether the toner is exhausted.
Moreover, according to the present embodiment, the toner stored in the toner storage unit 4c can be used without waste in order to detect the toner on the photoconductor 1.

[0022]

According to the present invention as described above, the toner directly on the image carrier is detected.
It is possible to reliably detect the toner end, reduce the amount of toner not used for image recording, and reliably consume the toner.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a main configuration of an apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view of a partial configuration of the apparatus shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging roller 3 Optical writing device 4 Developing device 4a Developing roller 4b Toner replenishing part 4c Toner storage part 5 Photosensor 6 Judgment part 7 Transfer roller 8 Cleaning blade 9 Laser diode 10 Collimator lens 11 Cylindrical lens 12 Polygon mirror 13 fθ lens 14 Reflecting mirror 15 Synchronous sensor 16 Synchronous lens

 ──────────────────────────────────────────────────続 き Continued from the front page F term (reference) 2H027 DA10 DD02 DE02 DE07 DE10 EA05 EA18 EC03 EC06 EC10 ED02 ED09 ED24 EF06 EF11 EF12 EF13 EK03 EK09 HB02 HB13 ZA07 2H073 AA02 BA02 BA09 BA13 2H077 DA02 DA18 DA18 DA18

Claims (6)

[Claims] An image carrier, a charging unit for charging the rotating image carrier, an image forming unit for forming an electrostatic latent image on the image carrier, a toner storage unit for storing new toner, and An image recording apparatus comprising: a developing unit having a developing unit for applying a toner to an electrostatic latent image formed on the image carrier; and a transfer unit for transferring the toner on the image carrier to recording paper. Means for detecting toner on the surface of the image carrier, which is disposed opposite to the surface of the toner image recording area of the image carrier between the means and the transfer means, based on a detection result of the toner detecting means. A determination unit that determines that the inside of the toner storage unit is out of toner when it is determined that the amount of adhered toner is smaller than a reference value or the toner is not attached, An electric field is formed between the image bearing member and the image bearing member so that the toner can be moved from the developing unit to the image bearing member. An image recording apparatus, wherein the detection is performed by a detection unit. 2. When the toner detecting means detects toner on the surface of the image carrier, the direction of an electric field between the developing means and the image carrier is switched to remove the toner on the image carrier. 2. The image recording apparatus according to claim 1, wherein the image carrier is rotated in the reverse direction while being movable to the developing device, and the toner on the image carrier is returned to the developing device. 3. The image forming apparatus according to claim 1, wherein the toner detecting unit includes a reflection-type photo sensor, and the determining unit determines whether the toner storage unit is at the toner end based on the amount of reflected light from the photo sensor. The image recording device according to claim 1 or 2, wherein 4. An image recording apparatus according to claim 1, wherein said toner detecting means is arranged at a central portion of a toner image recording area of said image carrier. 5. An operation for judging toner end by said judging means is performed before and after the end of recording on recording paper,
5. The image recording apparatus according to claim 1, wherein the recording operation is disabled when it is determined that the toner is out. 6. The image recording apparatus according to claim 5, wherein when it is determined that the toner is exhausted after the recording on the recording paper is completed, a recording error is determined and a signal requesting re-output is output.