JPS6155661A - Image recording device - Google Patents

Abstract

PURPOSE:To make maintenance and an inspection easy and form vivid multicolor images with a compact device by arranging image forming means around a photosensitive body with a high precision and constituting an image forming part unit attachably and detachably. CONSTITUTION:A photosensitive body 10 electrified uniformly by an electrifier 11 is exposed with a laser device 12, and an image is developed by a developing device A to form the first toner image, and the second and the third toner images formed similarly by electrifiers 13 and 14, laser devices 14 and 16, and developing devices B and C are superposed on the first toner image, and they are fixed to a recording paper P by a fixing device 25. An image forming part unit U1 and a transfer, fixing, and paper ejecting system unit U2 are constituted freely attachably and detachably with junction lines L1 and L2 as boundaries. Thus, the unit U1 is pulled out and parts are replaced to make the maintenance and the inspection easy, and excellent images are always formed stably because many image forming devices are arranged in the unit with a high precision.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image recording device that forms a multicolor image by superimposing a plurality of toner images on an image support, and relates to an image recording device that forms a multicolor image by superimposing a plurality of toner images on an image support. Used for facsimiles, laser blinking, computer output, etc.

[Prior art]

Conventionally, in electrophotographic copying machines, etc., the image forming section, which particularly requires maintenance such as troubleshooting, maintenance, inspection and cleaning, and parts replacement, is made into a unit, and the unitized image forming section is periodically replaced. Considerations have been made to reduce the maintenance effort by making it possible. For example, in JP-A-57-200052, JP-A-58-181061, and JP-A-58-181062, there are , an image recording apparatus is described in which a document table, an optical system, and an image forming section are included in an upper housing, and a housing can be opened and closed around a rotation axis.

The image forming section included in the upper housing is a detachable unit that includes a drum-shaped photoreceptor, a charger disposed around the outer periphery of the photoreceptor, a developing device, and a cleaning device. All known image recording devices that record black and white images using electrophotography have an image forming section arranged above a paper feeding system that includes transfer and fixing. The structure is easy to unitize.

By the way, in conventional multicolor image recording devices using electrophotography, the steps of charging, exposure, development, and transfer are repeated for each component and color, and toner images of each color are transferred onto recording paper in an overlapping manner. There is.

For example, a power-saving latent image is formed in each step using separated light of blue, green, red, etc., which is filtered through a color separation filter, and developed with yellow, magenta, cyan, and desired toner as necessary to form a toner image of each color. is formed, and each toner image is transferred onto recording paper to form a multicolor image.

However, in the image recording device that uses overcasting, it is necessary to transfer the image to the transfer drum each time the development of each color is completed.
In addition to the larger size of the machine, it also takes a longer time to form an image, ■ It is necessary to guarantee the accuracy of positional deviation due to repeated operations, and ■ The transfer drum increases the size of the machine and the parts of the image forming section. There are problems in that it is difficult to unitize as required for maintenance due to the diversification and difficulty of assembling them.

To improve this problem, an image recording device has been proposed in which a plurality of toner images are superimposed on a photoreceptor and developed, and the superimposed toner images are directly transferred to recording paper, eliminating the need for a transfer drum. .

However, even in such an image recording device, during the later stage development, the toner image obtained by the earlier stage development may be disturbed, or the toner in the earlier stage developer may be mixed into the latter stage developer, resulting in a multicolor image. There were drawbacks such as the color balance being disturbed.

Therefore, for example, Japanese Patent Application Laid-Open No. 144452/1982, Japanese Patent Application No. 1831.52/1982, and Japanese Patent Application No. 184381/1983 disclose that while developing is performed by applying a bias to the developing device, the photoreceptor and the A multicolor image recording apparatus has been proposed that uses a non-contact development method in which a power-saving latent image formed on a photoreceptor is not in contact with a developer layer for developing it. That is, a method is adopted in which a superimposed alternating current bias is applied in addition to the direct current bias as the bias to the developing device, and the toner in the developer is blown away and developed, and the previously developed toner image is not damaged by the subsequent development. This eliminates W-damages such as color balance being disrupted due to mixing of toners before and after the toner.

The image forming principle of the known technique will be explained below based on chart 70 in FIG. In FIG. 1, E is the positive surface potential applied to the surface of the photoreceptor, PHr
/φ Reij Omiya nA Kei Keifushi's JL Shimo no Sa-Du
p indicates the increase in potential caused by the positively charged toner T adhering to the exposure section l during the f51st development, and Cup indicates the increase in potential in the exposure section l caused by the first charging.

The photoreceptor is uniformly charged by a Scoo-on charger to give a constant positive surface potential E, which decreases to near zero potential at the exposed portion PH by the first image exposure. By applying a positive DC bias almost close to the surface potential E to the developing device to perform so-called reversal development, the positively charged toner T in the developing device is brought to the pH of the exposed area where the potential is relatively low. A first toner image is formed. In the area where the toner image is formed, the potential increases by Dup due to the adhesion of the positively charged toner 1.
Next, a second charging is applied by the charger, and the potential is further increased by Cup, and the initial surface potential E is obtained as in the non-exposed area DΔ. Next, the surface of the photoreceptor with a uniform surface potential E is exposed for the 12th time to form a power-saving latent image, and the H cost is small $+1 //#
Ume Red B Story Gu Jiku 9 N Correction! φ −
h('A↓ Eight illusions.

By revisiting the above process, a multicolor toner image (U) is formed on the photoreceptor, which is further transferred to recording paper, fixed by pressure or heat, and ejected. Any toner and charge remaining on the body is cleaned and prepared for subsequent multicolor image formation.

In an image recording apparatus that forms a multicolor image by superimposing a plurality of toner images on an image support as described above,
As mentioned above, there are advantages such as the transfer drum is not required, the device is made more compact, the time required for recording is shortened, and the overlay accuracy of each toner image is improved, resulting in a clear multicolor image. . However, it is required to arrange a large number of image forming means on the outer periphery of the image support body to form the plurality of toner images in a superimposed manner, and these image forming means are required to maintain the appropriate color balance of the multicolor image. Therefore, strict positional accuracy is required with respect to the image support or with respect to each other. Furthermore, since many of the troubles in image forming apparatuses occur in the image forming means on the outer periphery of the image support, there is a need for an hη structure that is easy to maintain. However, the reality is that no suitable device has been found in view of the complexity and precision of the image forming section unique to multicolor image recording devices.

[Purpose of the invention]

The present invention has been proposed in view of the above-mentioned circumstances, and an object of the present invention is to provide an image recording device in which a plurality of toner images are formed by superimposing each other, the image forming section of which is formed into a detachable unit. Accordingly, it is an object of the present invention to provide an image recording device that is easy to maintain.

Still another object is to provide an image recording apparatus that is compact, shortens the recording time, and can form clear multicolor images.

[Structure of the invention]

The above purpose is to provide an image recording apparatus that sequentially superimposes a plurality of toner images on an image support, in which at least one of the image forming means, such as a charger, a static eliminator, a developing means, an image exposing means, and a cleaning means, is used. This is achieved by an image recording device unitized with an image support.

The image forming unit in the present invention is mounted on a rail provided inside the main body, and the image forming device disposed on the outer periphery of the image support body constituting the unit is, for example, JP-A-55-105269, JP-A-56-77
858, Utility Model 58-45541, Utility Model 58-4
A predetermined gap is maintained through rollers, 7-runs, etc., as shown in Japanese Patent No. 7868, and screws are secured under the pressure of a spring.

However, as shown in FIG. 2, a step 3 for abutment is provided on the bearing 2 of the image support 1, and the step 3 is used to hold the image forming device 6.
It is preferable to keep a predetermined gap and fix by abutting against each other. In the figure, 4 indicates the rotation axis of the image support 1, and 5 indicates a driving motor.

〔Example〕

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the embodiments of the present invention are not limited thereto. 1
3 and 14 are diagrams for explaining this embodiment. FIG. 3 is a cross-sectional view of a main part of a three-color image recording device for explaining this embodiment, and FIG. 4 is a cross-sectional view of the image recording device shown in FIG. FIG. 5 is a sectional view of the developing device. In FIG. 3, 10 is a diameter of 300 mm and a peripheral speed of 1
Selenium drum photoreceptor rotating at 20n+m/sec, 1
1 is a first scorotron charger; 12 is a first laser device modulated by an external image signal for image exposure; A is a first developer containing yellow toner; 13 is a second scorotron charger; B is the second developer containing magenta toner, 15 is the third scorotron charger, I6 is: j
S3 is a laser device, and C is a third developing device that accommodates cyan toner.

17 is a pre-transfer charging and exposure device to increase transfer efficiency;
18 is a paper feeding device that accommodates records # and P, 19.20a
, ZOb, 23, 24, and 26 are conveyance rollers, 21 is a copying electrode, 22 is a separation electrode, 25 is a fixing device, 27 is a paper discharge tray, 28 is a pre-cleaning static eliminator, and 29 is a cleaning device. K is the main body of the image recording apparatus, Ul is the first unit including the image forming section, U2 is the second unit including the paper transport section, transfer section, and paper output tray of the fixing device, and Ll is the section between the first and second units. The joint m (and L2) is 3 based on the above configuration indicating the joint line (and
The unit mounting and image forming process of the color image recording apparatus will be explained below with reference to Figs. fj & 3 and 14. The image forming unit U is mounted along the rail in a vacant space in the main body of the apparatus in which the laser devices 12, 14, 16 are already arranged at predetermined positions and an idle rail (not shown) is provided. In this unit U, the tip of the rotating shaft of the photoreceptor 10 is fitted into and supported by a bearing provided at the rear of the main body, and the front surface of the photoreceptor 1o has, for example, the above-mentioned special
Unit U described in Publication No. 7-200052.

A lever is provided to prevent extraction. Further, a shielding member is provided in conjunction with this lever to shield the transfer section frontage S of the photoconductor 10, so that when the unit U1 is pulled out, the photoconductor 10
It is a good idea to protect the surface of the In addition, l) In the image forming unit U1, each image forming device arranged around the outer periphery of the photoreceptor 10 is installed so as to abut against an abutment member provided on either the photoreceptor 10 or the apparatus main body,
Furthermore, it is screwed under pressure by a spring.

Next, the recording paper P is pulled out from the paper feeding device 18 already installed in the X section of the main body of the apparatus, and is sandwiched between the transport rolls 23 of the unit U2 that is not yet installed. Next, the unit U2 is mounted along a rail (not shown) provided on the contact surface L2 of the paper feed section X.

The image recording apparatus in which the recording paper P is thus set forms an image by the following process. A first scorotron charger 11 applies a uniform charge of +600V to the photoreceptor lo, and then imagewise exposure is performed by a laser device 12 modulated by yellow data to form an electrostatic charge image.
It contains yellow toner and is developed by a developing device A having a structure to be described later to form a '1st toner image I#. Then, the voltage is increased to about +600V by the second charger 13 again.
Uniform charging is applied. Next, image exposure is performed by a laser device 14 modulated by magenta data to form an electrostatic charge image, which is developed by a developer B containing magenta toner and having the same structure as developer A to form a second toner image. be done. After being charged again in the same manner, a third toner image is formed by being processed by a laser device 16 modulated by cyan toner and a developing device C containing cyan toner, resulting in a color image in which these three color toner images are superimposed. A toner image is formed.

After this color toner image is charged by the pre-transfer charging device 17, the color toner image is charged to the conveying roll 1 in synchronization with the image forming process.
9 is fed, and 11 of the unit Ul is fed through the conveyor a-rule 20 to the copying part IJ)J opening part S, and the transfer electrode 21
The image is transferred onto the recording paper P. Next, the recording paper P is separated from the photoreceptor 10 by a separation voltage +izz, transported by transport rolls 23 and 24, and heated and fixed by a fixing device 25. After heating and fixing, the tray 2 is moved by the ejection roller 26.
7, but if necessary, it is folded and stored using a folding assisting member.

After the transfer is completed, the photoreceptor 10 is neutralized by a static eliminator 28, and the remaining toner is removed by a cleaning device 29.
removed by a cleaning blade.

The structure and operation of the developing device A will be explained based on FIG. 15. The developer contained in this container contains a pentunone derivative as a coloring agent, a nigemicin dye as a charge control agent, a toner having a weight average particle size of 10 m and a specific resistance of 1014 Ω1 or more, and iron tetraoxide dispersed in a resin. Consisting of
Weight average particle size 30n, magnetization 30e, Ill, u-/g
It is a two-component developer composed of a carrier having a specific resistance of 10'4Ω or more. The magnetic roll 30 having six poles is rotated in the direction of the arrow at a speed of 1000r, p, m, and the sleeve 31 with a diameter of 30n++n is rotated at a circumferential speed of 120mm/sec'' in the direction of the mark G. By being rotated, it is conveyed in the direction of arrow G. During the conveyance, a developer layer of 0.5 mm + thickness is formed by the spike control blade 32. In the developer reservoir 33, the developer layer is uniform. A stirring device 34 is provided for mixing, and a fixed amount of toner T is supplied from a hopper 36 via a supply roller 35 in response to a shortage of toner in the developer tank.

Next, the gap d between the sleeve 31 and the photoreceptor 10 is 0.8 mm.
During this time, a DC voltage of +500 V is applied from the power source 37 to perform reverse development. In order to vibrate the developer scraper in the rough development area E and allow the development to occur without contacting the photoreceptor 10, the power supply 38 is turned on with 2KllZ''C effective value 1,2.
An AC bias of KV is applied. Note that before reaching the development area E, the toner T is charged with a charge amount of 20 μc/g by triboelectric charging.

Developing units B and C have the same structure as developing unit A, and are developed under the same conditions, but the toner used in developing unit B is magenta toner in which Rhodamine B is used as a colorant, and the developer 4'J2 '! 5C is a cyan toner in which gi7 lysocyanine is used as a colorant.

In addition to the development method described above, as a modification of the development method in which development is performed without rubbing the photoreceptor, only the toner is taken out from the composite developer onto a developer transport carrier, and the toner is transferred in an alternating electric field. JP-A-59-425 that performs one-component development
There is a method described in Publication No. 65 and Japanese Patent Application No. 58-231434.

There is also a method described in JP-A-56-125753 in which a grain-like or mesh-like control electrode is provided and development is carried out using a one-component developer in an alternating electric field.

There is also a method described in Japanese Patent Application No. 58-97973 in which a similar control electrode is provided and development is carried out using a two-component developer in an alternating electric field. Any of these developing methods can be applied to the image recording apparatus of the present invention.

In the above-described image recording apparatus, when regular maintenance or component failure occurs, the image forming unit U can be pulled out and replaced with a spare unit, allowing the next image to be formed immediately. be.

If the component failure is simple, the component can be replaced regardless of the device itself. Further, with the above configuration, a large number of image forming devices on the outer periphery of the photoreceptor are mounted in the unit U1 with high precision, so that a clear image can always be obtained without fluctuation in the quality of the color image formed.

〔Effect of the invention〕

As explained above, in the image recording apparatus of the present invention that forms a plurality of toner images on an image support by superimposing them, a large number of image forming devices are arranged as a unit precisely arranged around the outer periphery of the image support. Since it is removable, maintenance and troubleshooting are easy, and images of excellent quality can always be stably formed.

[Brief explanation of the drawing]

Figure 1 is 7c explaining the principle of multicolor images by reversal development.
r-chart, FIG. 2 is a partial cross-sectional view illustrating the structure of mounting the image forming device in the abutment method against the image support, FIG. 3 is a cross-sectional view of the image recording apparatus of the embodiment, and FIG. 4 is the third FIG. 5 is a perspective view of the image recording apparatus shown in the figure, and FIG. 5 shows a developing device. 10... Drum-shaped photoreceptor 11.13, 15... Scorotron charger A, B, C
...: Developing device 12, 14, 16... Laser device U1... Image forming unit U2... Transfer, fixing, paper ejection system unit L,, L 2
...Uni-7F joint M (side) S...transfer section frontage

Claims (7)

[Claims] (1) An image recording apparatus in which a plurality of toner images are sequentially superimposed on an image support, characterized in that the image forming means is made into a unit with the image support and is removably attached. (2) Image recording according to claim 1, wherein the image forming means unitized with the image support is at least one selected from a charger, a static eliminator, a developing means, an image exposure means, and a cleaning means. Device. (3) Claim 1, wherein the image forming means unitized with the image support is positioned by abutment.
The image recording device according to item 1 or 2. (4) The image recording apparatus according to claim 2, wherein the charger is a scorotron charger. (5) The image recording apparatus according to claim 2, wherein the developing means comprises a plurality of developing devices that perform reversal development. (6) The image recording apparatus according to claim 2 or 5, wherein the developing means is a means for performing non-contact development from the second time onwards. (7) A laser device, liquid crystal (LC) device, or light emitting diode (LED) device in which the exposure means is modulated or driven by an output signal from an image sensor that scans a document, a transmission signal from another device, or an output signal from a memory. The image recording device according to claim 2, which is a cathode ray tube device.