JPH01193772A - Developing device for image recorder - Google Patents

Abstract

PURPOSE:To obtain a distinct image being free from a color slippage and the unevenness of color by providing a pressing member consisting of a viscoelastic body so that a developing device can be pressed against an image carrier by this pressing member. CONSTITUTION:A pressing member 21 consisting of the viscoelastic body is provided so as to be used in a stable area at the time of installing a developing device 11, and by its pressing force, a pressing pin 20 presses the rear end face of a casing 11e by prescribed force by its head part. Accordingly, since the whole developing device 11 is pressed to an image carrier 1 side by prescribed force, abutting force between an auxiliary roller 11f and the image carrier 1 is kept constant. As a result, a developing gap between the surface of the image carrier 1 and a developing sleeve 11d is also kept constant at all times. In such a way, the distinct image being free from the color slippage and the unevenness of color can be obtained.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an image recording device such as an electrophotographic copying machine or an electrostatic recording device, and more specifically, toner is attached to an electrostatic latent image formed on the surface of an image carrier in the recording device to form a toner image. The present invention relates to a developing device.

[Background of the invention]

Generally, in an image recording device such as an electrophotographic copying machine or an electrostatic recording device, a rotating drum type image carrier having a photoconductive photosensitive layer on the outer peripheral surface is used, and while the image carrier is rotated, the photosensitive layer is An electrostatic latent image is formed on the surface and developed with toner.
The obtained toner image is transferred to recording paper. Particularly, in a color image recording device that forms a color image by combining monochrome images, a plurality of developing units loaded with toner of each color are arranged around the periphery of the image carrier, and each rotation of the image carrier A latent image corresponding to each color is developed in a non-contact manner using a developing device loaded with toner of that color, and a multicolor toner image is formed by multiple rotations of the image carrier. It looks like this.

[Problems to be solved by the invention]

In the above-mentioned developing device, development is performed for each color multiple times, so in order to obtain a clear image without color shift or unevenness, the gap between the developing sleeve of each developing device and the surface of the image carrier, that is, the developing gap, must be maintained. It is necessary to keep the amount small and constant. For this reason, each developing device is provided with a pair of auxiliary rollers near both ends of the developing sleeve, and is also provided with a pressing spring that presses the developing device itself toward the image carrier. However, since the force generated by the spring is proportional to the amount of displacement, there is a drawback that the pressing force changes due to external force or slight deformation of the image carrier, and the developing gap also changes. In order to absorb such fluctuations, a spring with a long free length must be used, which has the disadvantage of requiring a large space.

[Means to solve the problem]

The present invention has been made in order to eliminate the above-mentioned drawbacks, and it is possible to obtain a constant pressing force in a small space despite external forces and deformation of the image carrier, and to maintain a constant development gap. The object of the present invention is to provide a developing device for a recording device. The above object is to provide a developing device of an image recording device that forms a toner image by adhering toner to an electrostatic latent image on the surface of an image carrier, a pressing member made of a viscoelastic body is provided behind the developing device, and the developing device This is achieved by a developing device of an image recording apparatus characterized in that the image forming apparatus is configured to be pressed against the image carrier by the pressing member.

【Example】

An embodiment of the present invention will be described based on the attached drawings. FIG. 1 is a block diagram of a part of the printer of the image recording apparatus. An overview of the functions of the image recording apparatus will be explained with reference to the figure. The image carrier 1 is formed by depositing or coating a photoconductive photosensitive layer on the surface of a conductive support cylinder. Reference numeral 2 denotes a charger disposed above and close to the image carrier l. The charging charger 2 performs corona discharge to sequentially charge the image carrier 1 as the image carrier 1 rotates in the direction of the arrow. In a reading unit (not shown), the original is illuminated by a light source, and the optical image of the original is captured by an imaging lens or multiple CCDs.
It is read by a reading means consisting of. The image signal output from the COD of the reading means is subjected to signal processing in the signal processing section. From the signal processing section, a color signal separated according to the color of the toner is inputted to the writing unit A. In writing unit A, a laser beam generated by a semiconductor laser is rotated and scanned by a polygon mirror 5 rotated by a drive motor 3, passes through an Fθ lens, has an optical path bent by a reflecting mirror 4, and is directed to the image carrier. 1. When scanning is started, the laser beam is detected by the index sensor, and modulation of the beam by the first color signal is started. The modulated beam scans over the image carrier l, which has been uniformly charged in advance by the charger 2. A latent image corresponding to a first color, for example, cyan, is formed on the surface of the image carrier by main scanning by the laser beam and sub-scanning by the rotation of the image carrier l. This latent image is developed by a developing device 6 loaded with cyan toner, and a cyan toner image is formed on the surface of the image carrier. The obtained toner image, while being held on the surface of the image carrier, passes through the opposing portion of the cleaning device 7, which is separated and retracted from the surface of the image carrier, and enters the next image forming cycle. The image carrier 1 is uniformly charged by the charger 2. Next, the second color signal output from the signal processing section is input to the writing unit I-A, and written on the surface of the image carrier in the same manner as in the case of the first color signal, forming a latent image. be done. The latent image is developed by a developer 9 loaded with a second color, for example magenta toner. This magenta toner image is formed to overlap the cyan toner image already formed on the surface of the image carrier. Furthermore, the third color signal output from the signal processing section is input to the writing unit A, and is written on the surface of the image carrier in the same manner as in the case of the first and second color signals, thereby forming a latent image. is formed. The latent image is developed by a developer 10 loaded with a third color, for example yellow toner. This yellow toner image is formed to overlap the cyan toner image and magenta toner image that have already been formed on the surface of the image carrier. Reference numeral 11 denotes a developing device having black toner, which forms a black toner image on the surface of the image carrier based on a control signal generated by a signal processing section. The developing sleeves of these developing devices 8.9.10.11 include:
AC and DC biases are applied to perform jumping development using a two-component developer. The superimposed image of the toner images developed in this way is transferred by the transfer pole 12 onto the recording paper P, which is a transfer body, fed from the paper feed section B. The transfer paper to which the toner image has been transferred is separated by a separation pole 13 and a separation claw 1.
4 is separated from the surface of the image carrier 1, conveyed to the fixing device 15, and fixed thereon to obtain a recorded matter. A cleaning device 7 acts on the image carrier 1 after the transfer to remove unnecessary toner remaining on the peripheral surface. The removed toner is once collected in the cleaning device 7 and conveyed to the toner discharge port of the cleaning device. The toner discharged from the toner discharge port is
The toner is collected by the toner collection device 6 and stored in the toner collection box of the device. Next, the structure of the developing device will be explained by taking the developing device 11 loaded with the black toner as an example. FIG. 2 is a sectional view of the developing device 11, and FIG. 5 is a perspective view thereof. In the figure, lla and llb are stirring screws that stir the developer, 11C is a conveyance roller, and lld is a developing sleeve, each of which is rotatably housed in the casing 11e of the developing device. An auxiliary roller llf is rotatably supported at the tip of the casing lie, and this rotates while contacting the image carrier 1 to create a gap between the developing sleeve lid and the surface of the image carrier 1. A developing gap is ensured. Direct current and alternating current bias voltages are applied to the developing sleeve lid, and jumping development using the two-component developer is performed. The image carrier is constructed so that development is performed in a non-contact state between the grounded surface of the image carrier and the developing sleeve lid. The casing lie is slidably mounted on a support plate 16 fixed to the main body of the image recording apparatus. 17. 17 is a pair of handles in the shape of an abbreviation, and the handles 1
7.17 is fixed to the shaft 18.18, which shaft 18.17 is fixed to the shaft 18.18.
18 is a shaft hole 11G bored in the casing glie;
It is arranged to be slidable and rotatable by IIG and bearing parts 11H, 11H. Also, the shaft 18.18 is connected to the spring 19.1.
It is pulled and biased outward by 9. A slidable push pin 20 is provided at the bottom of the handle 17.17.
．． 20 is fitted, the head of the pin 20.20 is arranged so as to be able to come into contact with the rear end surface of the caning lie, and a pressing member 21.21 according to the present invention is fitted to the shaft portion. As shown in FIG. 6, the pressing member 21.21 has a cylindrical shape in its natural state. The pressing member 21 is a viscoelastic body made of chloroprene rubber having a hardness (rubber hardness) of 40 to 50 degrees. A groove-shaped engagement portion 17a is provided at the bottom of the handle 17.17. 17a is formed. A pair of hook-shaped locking portions 16a, 16a are formed on the support plate 16, and the locking portions 16a, 16a,
It is configured to be compatible with 16a. The embodiment of the present invention is constructed as described above, and its operation will be explained next. When the pair of locking portions 16a of the support plate 16 and the pair of retaining portions 17a of the handle are engaged as shown in FIG. 2, the pressing member 21 is compressed to be shorter than its natural length. has been done. When a viscoelastic material such as chloroprene rubber is compressed in the axial direction, the third
Incidentally, as shown by the solid line, there is a stable region in which the generated force does not change much even if the amount of displacement is changed. This shows that the pressing force can be kept constant even when the amount of compression changes. In addition, what is shown by a dotted line in FIG. 3 is a characteristic curve showing the relationship between the amount of displacement of a spring (such as a coil spring) and the generated force. Since the pressing member 21 is arranged so as to be used in the above-mentioned stable region when the developing device 11 is attached, the pressing force causes the pressing pin 20 to apply a constant force to the rear end surface of the casing lle with its head. Press. Therefore, since the entire developing device 11 is pressed toward the image carrier l with a constant force, the contact force between the auxiliary roller Ilf and the image carrier l is also kept constant. As a result, the development gap between the surface of the image carrier l and the development sleeve lid is always maintained constant, and a toner image without color shift or color unevenness can be obtained. FIG. 4(A) is a plan view showing a state in which the handle and the support plate are engaged, and FIG. 4(B) is the front view. When removing the developing unit from the main body of the apparatus for maintenance or inspection, press the pair of handles 17 from above with your fingers and rotate them slightly clockwise in FIG. The locking portion 16a is separated from the locking portion 16a. In this state, each handle 17 is held against the spring 19, and the shaft 18 is moved as shown by the dashed line in FIGS. 4(A) and 4(B).
When the developing device 11 is pulled inwardly toward the supporting plate 1
It can be removed from 6. Although the description has been made by taking the developing device 11 out of the four developing devices as an example, the other developing devices are configured in exactly the same manner and produce the same effects.

【Effect of the invention】

According to the present invention, a minute developing gap between the developing sleeve of the developing device and the surface of the image carrier can be removed in a small space.
It is possible to hold the image carrier constant despite external forces and slight deformation of the image carrier itself, and as a result, it has become possible to obtain images without color shift or color unevenness. Furthermore, it is possible to attach and detach the developing device with only a slight rotation and sliding movement of the handle, thereby providing a developing device for an image recording device that is easy to maintain and inspect.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of the printer section of the image recording apparatus according to the present invention, Fig. 2 is a sectional view of the developing unit, Fig. 3 is a characteristic diagram showing the relationship between the displacement amount of the pressing member and the generated force, and Fig. 4 ( A) is a plan view showing a state in which the handle and the support plate are engaged, FIG. 4(B) is a front view showing the above-mentioned state in engagement, and FIG. 5 is a perspective view of a developing device showing an embodiment of the present invention. FIG. 6 is a perspective view of the pressing member. ■...Image carrier! It, 9, 10.11...Developer (developing device) 21
...Press member

Claims (2)

[Claims] (1) In a developing device of an image recording device that forms a toner image by adhering toner to an electrostatic latent image on the surface of an image carrier, a pressing member made of a viscoelastic body is provided behind the developing device, and the developing device A developing device for an image recording apparatus, characterized in that the developing device is configured to be pressed against the image carrier by the pressing member. (2) A developing device for an image recording apparatus according to claim 1, wherein the pressing member is a cylindrical body made of chloroprene rubber.