JPS61200569A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the mixing of toner and to shorten a waiting time by erasing an image on an image carrier and releasing a toner developing device from being held while an image exposing means is powered on when an indication for the replacement of the toner developing device is generated. CONSTITUTION:When the replacement of the toner developing device 22 is indicated with a switch SW2, a belt 14 makes one turn to erase an image formed thereupon and a belt driving motor M1, a developing motor, and a developing bias power source are turned off. Then while an image exposing device 15 is powered on, the toner developing device 22 is released from being held by a holding plate 38. Therefore, even when the toner developing device 22 is replaced, toner particles before and behind are never mixed together and the resulting color mixture is not caused. Further, even when the toner developing device 22 is replaced for reuse, the power source need not be turned on again and the wait time up to readiness in use is shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an image forming apparatus that forms an image on an image carrier such as a photoreceptor belt or an insulated drum.

[Prior art]

2. Description of the Related Art Conventionally, CRT (cathode ray tube) display devices and liquid crystal displays have been put into practical use as image forming devices that visualize and display image information converted into electrical signals.

Of these, CRT display devices are the most commonly used and highly reliable devices, but their resolution is limited, so they can be used to display small characters such as those used in newspapers and magazines, especially those with a large number of strokes such as kanji. Many small characters cannot be displayed in their original size.

For this reason, we have enlarged the display so that it can be deciphered.
The number of characters that can be displayed on the screen decreases in inverse proportion to the magnification rate.
- There is a problem that the amount of information per screen is reduced. Furthermore, if the same image is displayed continuously for a long time, the screen will be burned in, resulting in a decrease in display performance. In addition, if one screen flickers.

My eyes get tired.

On the other hand, a liquid crystal display device is a display device that has recently been put into practical use, but like the CIIT display device, it has insufficient resolution and has similar problems.

Furthermore, due to the nature of liquid crystal, it is difficult to make large screens, and even if they were made, they would be expensive.

Therefore, as a third image display device free from such drawbacks, the present applicant previously proposed an image display device using electrophotography (Japanese Patent Application No. 58-197410-1974).
No. 13), this display device reproduces and displays one image information as a toner image, has excellent resolution, and the image is easy to see.
A device with a large screen can be manufactured at a relatively low cost and is a highly reliable device.

This image forming apparatus is configured to attach toner to a belt-shaped photoreceptor to form an image and display the image. In the case of maintenance or repair, the developing device constituting the image forming section, that is, the toner developing device, is removed from the image forming apparatus or replaced.

For example, in the case of color display (multicolor display), toner is colored, a toner developing device containing the colored toner is attached to an image forming apparatus, and images are formed and displayed in different colors.

That is, a toner developer holding colored toner is used for each color, and these are replaced and installed in the image forming apparatus to perform color display (multicolor display).

Also, if the toner stored in the toner developing device deteriorates or foreign matter gets mixed in with it, the developing device should be removed from the image forming apparatus, the toner replaced, the foreign matter removed, etc., and the developing device reinstalled. It is designed to be worn.

However, in this image forming apparatus, since the toner developing device is replaced by attaching and detaching it to the image forming J& device, the toner image produced by the toner developing device before replacement may adhere to the photoreceptor. This may get mixed up with the toner in the newly installed toner developer, especially when performing color display (multicolor display).
There was a problem that color mixing occurred.

In addition, when replacing the toner developer, the power must be turned off for safety reasons, so when the power is turned on again after replacement, there is a waiting time until the initial operating state is reached (time until the various drive systems start up). This is inconvenient for the user of the image forming apparatus.

〔the purpose〕

This invention has been made to solve these problems, and allows the image on the image carrier to be erased and the image forming means to be replaced in response to an instruction to replace the image forming means by the instruction means. By configuring the holding means to be released, for example, it is possible to prevent toner mixing and color mixing, and furthermore, it is possible to shorten the waiting time when using the image forming means again after replacing the image forming means. The object of the present invention is to provide a forming device.

〔Example〕

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

This embodiment reproduces and displays image information converted into an electrical signal that is calculated or read out from a computer, image reading device, etc., or image information that is stored as a soft copy on a magnetic tape, etc., as a visible image. This image forming apparatus is suitable as an image monitoring apparatus in a terminal display or a league apparatus, an office automation apparatus such as a copying machine, or other image-related equipment.

First, the principle of image formation by electrostatic photography to which the present invention can be applied will be explained with reference to FIGS. 1 and 2.

FIG. 1 shows the state of charge in the bright area. When the toner 5 to which a voltage is applied comes into contact with the photoreceptor A, an electric field is applied to the photoconductive layer 2 . At this time, when the image light is irradiated, photocarriers e are generated in the photoconductive layer 2, and the photocarriers e are guided near the surface of the photoconductive layer 2 by the action of a central field. As a result, a strong electrostatic attraction force acts between the toner 5 and the photoconductive layer 2, and the toner 5 adheres to the photoconductive layer 2, that is, the surface of the photoreceptor A.

In the illustrated example, the photoconductive layer 2 is an N-type semiconductor and a positive voltage is applied to the toner 5, so that the electrons generated in the vicinity of the substrate 1 in the photoconductive layer 2 due to the irradiation with image light are It is easily guided toward the surface of the conductive layer 2.

As a result, a strong electrostatic attraction acts between the toner 5 and the photoreceptor A, and the toner 5 adheres to the photoreceptor A.

FIG. 2 shows the state of charge in the dark area. When an electric field is applied between the toner 5 and the conductive layer 1b of the substrate 1, electrostatic attraction acts between the toner 5 and the conductive layer 1b, but since the photoconductive layer 2 exists between them, the distance is The force is small because the two are separated from each other. Therefore, due to the magnetic force of the magnet 3 provided inside the fixed sleeve 4, the adhesion force between the toner 5 particles, etc., the toner 5 is transferred to the photoconductive layer 2, that is, the photoreceptor. It is pulled from the surface of A.

In this way, the toner 5 adheres to the bright areas of the photoreceptor A, and an image is formed without toner 5 adhering to the dark areas.

When changing the display content, the photoreceptor A having a toner image on one surface is used again as it is. In this case, since the toner image on the surface of the photoreceptor does not have any adverse effect on the next image formation, there is no need to provide a separate cleaning means, and during the next image formation, unnecessary The toner image is erased.

3 to 5 show embodiments of this invention.

In this embodiment, the present invention is applied to an image forming apparatus that displays images based on the principle of image formation by electrostatic photography.
The figure is an enlarged view of the main part of Fig. 4. In Fig. 0, 6 is the vertical exterior position, 7 is a large opening formed in the front plate of this exterior casing 6, and 8 is the window hole for viewing the display image. 6 is an operation panel arranged on the top surface of the base part 6a; 9 is a display window glass placed in the window hole 7;
O, 11, 12, 13 are image carriers to be described later, that is,
A roller that suspends the endless belt-type photoreceptor 14 moves the axis of the outer casing 6, two at each of the upper and -F sections of the outer casing 6.
horizontally and parallel to each other.

In addition, they are each arranged so as to be rotatably supported. 14
is the aforementioned endless belt type photoreceptor (hereinafter abbreviated as belt) suspended around these four wooden rollers 10, 11, 12, and 13.

For example, the belt 14 has a base layer that is a transparent sheet such as a polyester sheet, has a very thin layer of metal vapor-deposited on its outer surface to provide conductivity while substantially maintaining transparency, and has a metal-deposited layer on the metal-deposited surface. Photosensitive material layer (photoconductive layer) such as CdS
was formed. It is entirely flexible and is suspended around the four wooden rollers with the photosensitive material layer side facing outward.

Of the four rollers mentioned above, roller lO is a driving roller that drives belt 14 counterclockwise. When this roller 10 is driven by motor M+ (Fig. 4), the other three rollers 11, 12, and 13 It is designed to rotate in a driven manner. Of these three rollers, roller 11 is a belt tension roller, which applies tension to belt 14. That is, the belt 14 is designed to rotate counterclockwise without waving, sagging, or slipping.

With this rotation, the belt 14 between the rollers 10 and 13 moves from bottom to top while exposing its outer surface to the window hole 7 of the exterior casing 6 as an image display section.

An image forming unit that forms a visible image on the belt 14, that is, an image forming section, includes rollers 12 and 13, as will be described later.
The image display section located between the rollers 1 and 1 and displaying this image is
3 and 10, and a visible image formed on the bell) 14 in the image forming section is displayed through the window hole 7 in the image display section.
displayed through.

The image forming section includes a laser beam scanning type image exposure bag 2115 provided inside the belt 14 and a toner developer for developing an electrostatic latent image formed on the belt 14 by the image exposure device 1115. 22.

The image exposure device 15 is disposed inside the bell) 14,
Semiconductor laser oscillator 16. polygon mirror scanner 17
．． It has an fO lens 18, a reflector 19, and two exposure rollers 20, 21.

These two fog rollers 20 and 21 are arranged parallel to each other between the rollers 12 and 13 to form a slit through which the laser beam L passes.

In the image exposure bag 2t15, a laser beam L corresponding to a time-series electric pixel signal output from an electronic computer, image reading device, etc. is oscillated from a semiconductor laser oscillator 16 toward a polygon mirror scanner 17. The laser beam L incident on the scanner is swung in the belt width direction f
The laser beam passes through the θ lens 18, the reflecting mirror 19, and the slit between the exposure rollers 20 and 21 in sequence, and is incident on the inner surface of the belt portion between the rollers 12 and 13, and the inner surface of the belt portion is scanned with a laser beam in the belt width direction. Image exposure is performed from the inner surface of the belt 14 by using this laser beam scanning as a main scanning and the rotational movement of the belt 14 as a sub-scanning.

The toner developing device 22 is disposed close to the outer surface of the track of the exposed portion of the belt between the rollers 12 and 13. The electrostatic latent image formed on the bell 14 by the toner developing device 22 is visualized by the above-mentioned simultaneous exposure and development process.

Thereafter, the belt 14 is driven by the drive roller 1O and is transported to a position facing the display window glass 9, where it is used for display.

The exposure rollers 20 and 21 have a bell) 14.

It is arranged so as to be held outside of a common external tangent line connecting the pair of instruction rollers 12 and 13 before and after it.

That is, the exposure rollers 20 and 21 are arranged so that their lower surfaces project slightly downward from the common external tangent line on the lower side of the rollers 12 and 13. Therefore, these exposure rollers 20 and 21 are in pressure contact with the belt 14 inwardly, and the belt 1
4, a constant tension is always applied to maintain the flatness of the photoreceptor belt in the exposure area.

Rotates smoothly as the belt moves. Further, the photosensitive rollers 20 and 21 are caused by waving or vertical movement of the belt 14 due to rotational movement, or by contact with the developing brush (brush-like accumulation of developer formed by a magnet) of the toner developing device 22. This prevents vertical movement of the bell) 14 and maintains the developing position and exposure position constant to improve the developing power. As described above, the toner developing device 22 is disposed outside the belt 14 and can be pulled out in the direction of arrow A, which is substantially parallel to the common external tangent.

FIG. 5 shows a developing device, that is, a toner developing device 22,
A holding device H as a holding means and a toner developing device 22
This is an enlarged view of the corresponding part in FIG. 4, showing the detection device for detecting the presence or absence of the device (whether or not it is installed in the storage section 6b of the exterior casing 6). The toner developing device 22 is constructed by housing a supporting portion 33 that integrally supports each member of the developing roller 30 and the hopper 32 that stores the toner 31 in a developing tray 36 as one unit. The unit you are looking at has fixed shafts 34 fixed to both ends of the developing plate 36.
During image formation, the developing roller 30 is supported rotatably by an elastic member 35 provided between the rear end of the support section 33 and the developing tray 36, and is aligned and stationary with a predetermined small gap maintained relative to the bell) 14. It is set up to do so. This toner developing device 22 is opened by holding the handle part 36a of the developing tray 36 and
It can be easily attached and detached by inserting it into the storage section 6b or pulling it out.

In the holding device aH, numeral 38 is a holding plate for the toner developing device 22, and a sloped portion 38a at the tip is hooked to the rear end of the toner developing device 22 to hold it so that it does not come off. The center part of this holding plate 38 is attached to a vehicle 39 fixed to the exterior casing 6.
It is attached so that it can swing between the (solid line) position and the C (broken line) position. Reference numeral 40 denotes an elastic member that biases the holding plate 38 to the C position.

A plunger 41 holds the holding plate 38 at the B position, that is, at the position where the toner developing device 22 is engaged, against the tensile force of the elastic member 40 .

Since the holding device 'aH has such a structure, when the plunger 41 is energized, the holding plate 38 rotates to the Ill position against the tensile force of the elastic member 40, and the toner developing device 2 is rotated.
When the 0 energization hooked to 2 is released, the tensile force of the elastic member 40 moves it back to the C position.

That is, when the plunger 41 is energized, the toner developing device 22 is held by the holding PII 6b of the exterior housing 6, and when the plunger 41 is not energized, the toner developing device 22 is released from the retaining plate 38 and can be removed. Become.

The sensing device ff1K is a switch SWI in this example. The switch SW+ is turned on when the front end of the toner developing device 22 comes into contact with the switch lever 37, and turned off when the front end of the toner developing device 22 comes away from the switch lever 37. Therefore, if the toner developing device 22 is in the ON state, it is installed in the storage section 6a, and the toner developing device 22 is in the OFF state.
If it is in good condition, you will know that it is not attached. 5W2 (FIG. 3) is a switch serving as an instruction means for instructing replacement of the toner developing device 22.

FIG. 6 shows an example of the configuration of the control section of the image forming apparatus shown in FIGS. 4 and 5. is a controller that recognizes the operator's designation based on the input signal from the operation panel 8 and controls predetermined operations. 43 is a control circuit for the motor M1 that drives the roller 10, 44 is a drive circuit for the motor M2 that drives the developing roller 30, that is, a developer drive circuit, and 45 is a DC developing bias that applies +200V to +300V to the toner developer 22. A developing bias circuit that applies voltage, 46 a drive circuit for the image exposure device, 47 a laser drive circuit that drives the laser oscillator 16, 4B a drive circuit for the plunger 41, 49 from external equipment such as an image reading device and an external storage device. The transmitted image signal (video signal) 50 is a belt clock sensor, which is a sensor such as a photo encoder that is directly attached to the shaft of the drive roller 10, and generates a pulse P every time the drive roller 10 rotates by a certain angle.
is generated. The controller 42 counts these pulses P and measures the amount of movement of the belt 14.
Control the movement and stopping of.

Next, the operation of the image forming apparatus having the above configuration and the operation when replacing the toner developer rji 22 will be explained according to the flowchart shown in FIG.

First, when the power of one image forming apparatus is turned on, the motor of the apparatus is rotated by the drive circuit 46 of the image exposure apparatus. (
step 1ot).

Next, it is determined by the switch SW1 whether the toner developing device 22 is installed in the storage section 6a of the outer cylinder 6 (step 102). If the toner developing device 22 is not installed in the storage section 6a, A command is given to the operator to install the toner developing device 22 (step 103).

When the toner developing device 22 is installed, the roller l
A motor M1 that drives the developing roller 30, a motor M2 that drives the developing roller 30, and a motor M2 that drives the developing roller 30. The developing bias circuits 45 are each in a state where they can be energized. Further, the plunger 41 is energized, and the toner developing device 22 is latched by the holding plate 38 and held in the storage portion 6a (step 104). Then (step 10B), the waiting motor M rotates,
The belt 14 begins to move by the rollers 10. Further, the motor M2 also rotates, and a developing bias voltage is applied.

When the belt 14 moves, counting of pulses P is started, and exposure scanning is performed with a laser beam L modulated by an image signal.

When writing of the image signal to the belt 14 is completed, that is, when the rear end of the exposure area of the belt 14 passes the developing position, the motor M2 is turned off, the application of the developing bias voltage is canceled, and the belt 14 enters a standby state. Then, when the count value of the pulse P reaches a predetermined value, the motor M1 stops and the belt 1
4 stops. At this time, the image formed on the bell) 14 is visible through the window hole 7 (step 107).

On the other hand, in step 105, when the switch SW2 on the operation panel 8 instructs to replace the toner developer 22, the controller 42 does not control the exposure scanning by the laser beam L, but controls the driving of the motors M1 and M2 and the development bias. A voltage is applied, pulses P generated as the belt 14 moves are counted, and the belt 14 is controlled to stop when it has made one rotation (step tOa), that is, a command to replace the toner developing device 22 is issued. and belt 14
Control is performed so that the image formed above is automatically erased. 6) When the ring 14 rotates once and image erasure is completed.

Motor Ml, motor M2. Then, the power to the developing bias voltage is released, and the energization to the plunger 41 is also released (step 109).The toner developing device 22 released from holding in this way can be operated without removing all the power supplies. Replacement, maintenance, repair, etc. can be performed while the motor of the image exposure device 2t15 is energized (step 110).

After completing these processes, the toner developing device 22 is turned on again.
When the is attached to the storage part 6b, the process returns to step 102.
It enters a standby state in preparation for the next operation.

As described above, in this embodiment, when the switch SW2 instructs to replace the toner developing device 22, the belt 14 rotates once to erase the image formed thereon, and the belt drive motor M1 and the developing motor The toner developing device 22 is released from being held by the holding plate 38 while the power supplies of M2 and the developing bias voltage are 0FFL and the image exposure device al15 is still energized.

Therefore, even if the toner developing device 22 is replaced, the toners before and after the toner developing device 22 may mix.

There is no possibility of color mixing occurring. Also.

Even when replacing the toner developing device 22 and using it again,
There is no need to turn on the power again, and the waiting time until the device is ready for use can be shortened.

The above embodiment is an example in which the present invention is applied to an image forming apparatus using an electrophotographic method. It is also convenient to apply this invention.

〔effect〕

As described above, according to the present invention, when an instruction is given to replace the image forming stage, the image on the image carrier is erased and the image forming means is replaced while the image forming means is still energized. Since the holding is released, it is possible to prevent toner mixing before and after replacing the image forming means and color mixing caused by this, and to shorten the waiting time when using the image forming means again after replacing the image forming means. Can be done.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams for explaining the principle of image formation by electrostatic photography to which the present invention can be applied;
4 is a sectional view of FIG. 3, FIG. 5 is an enlarged view of the main part of FIG. 4, and FIG. FIG. 7 is a block diagram showing an example of the configuration of the control section of the example, and is a flowchart showing an example of the operation of the image forming apparatus of the example. 8......Operation panel 14...Endless belt type photoreceptor (image carrier)
15... Image exposure device 22... Toner developer (developing device) SW2...
・Switch (means for instructing replacement of the developing device) H...... Holding device K...... Detecting device 11 Figure IIG Cause 71! f

Claims (1)

[Claims] an image bearing member, an image forming means for forming an erasable visible image on the image bearing member, a holding means for holding the image forming means in a replaceable manner, and an instruction for instructing replacement of the image forming means. means for erasing the visible image formed on the image carrier in response to a replacement instruction from the instruction means; and a holding means for enabling the image forming means to be replaced after the image has been erased. An image forming apparatus characterized by comprising: means for releasing the .