JPS60233665A - Two-color developing device for nonmagnetic one-component type developer - Google Patents

Abstract

PURPOSE:To obtain a uniform image free frim unevenness in development without increasing manufacturing cost by bringing tracking rolls into uniform contact with a photosensitive body. CONSTITUTION:The tracking rolls 10-13 fixed to the outside of side frames 7, 8 are rotated in contact with the photosensitive body 1 as it rotates. Screws 14, 15 are brought into contact with the outside wall of a holder 9 and fastened with lock nuts 16, 17 so as to adjust the pressure of the roll 10 to be given to the body 1 as same as that of the other rolls 11-13, and the rolls are fixed in these states. The frames 7, 8 are connected with elastically deformable tie bars 18, 19, and held with studs 20, 21 protruding outward. The studs 20, 21 are located so as to balance the moments due to the gravities of the developing housings of developing rolls 3, 4, etc. Therefore, even if slight gaps occur between the rolls 10-13 and the body 1, slight twist can be allowed with the elastically deformable tie bars 18, 19, and they are held with the studs located at the positions equal to the moments of the developing devices, hence, permitting the uniform contact of the rolls 10-13 with the photosensitive body 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developing device, and more particularly to a two-color developing device that performs two-color development using a non-magnetic component developer.

[Prior art]

The two-color developing device described above is provided with two developing rolls and two toner equalizing rolls that are in pressure contact with the developing rolls, and has a bearing portion to rotatably support the four rolls. There are left and right side frames. Four tracking rolls are attached to the outside of the side frame G so as to be in pressure contact with the photoreceptor, and these tracking rolls maintain a constant gap between the developing roll and the photoreceptor.

In order to maintain the color developing device having two developing rolls as described above at a uniform distance from the photoreceptor, 4.
It is necessary to ensure that the two tracking rolls are in uniform contact with the photoreceptor. However, processing the tracking roll in this manner significantly increases manufacturing costs, and even if a large amount of money is spent, it is almost impossible to bring the tracking roll into completely uniform contact with the photoreceptor. Therefore, there is a problem in that uneven development occurs due to poor tracking, making it impossible to obtain a uniform image.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned drawbacks, and provides a two-color developing device that can easily achieve uniform contact between a tracking roll and a photoreceptor without increasing manufacturing costs, thereby eliminating uneven development. The purpose is to obtain beautiful images.

[Structure of the invention]

The present invention includes two developing rolls, two toner equalizing rolls that are in pressure contact with the developing rolls, and left and right side frames that have bearings that rotatably support the four rolls, and which are attached to the outside of the side frames. In a two-color color developing device for a non-magnetic component developer, which has four tracking rolls that are pressed against the photoreceptor to maintain a constant gap between the developing roll and the photoreceptor, the upper end portions of the left and right side frames and a lower end thereof is connected by an elastically deformable tie bar, and studs for supporting the developing device are provided at positions of the left and right side frames such that moments in the developing device are equalized, and further, the developing roll and the uniformizing device are provided with studs for supporting the developing device. The present invention is characterized in that an adjustable means is provided for pressing only one of the bearing portions of the roll toward the photoreceptor while maintaining the pressing distance between the developing roll and the uniformizing roll.

〔Effect of the invention〕

According to the present invention, the gap between the developing roll and the photoreceptor can be kept constant while maintaining the pressure contact distance between the developing roll and the toner equalizing roll. Therefore, a uniform image without uneven development can be obtained.

〔Example〕

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

1A and 1B are a side view and a front view of a two-color developing device according to the present invention. Referring to the drawings, the developing device includes a developing housing 2 disposed adjacent to a photoreceptor 1. As shown in FIG. A developing roll 3 is provided inside the developing housing 2.
4 are provided, and a toner equalizing roll 5.6 is pressed against each of these developing rolls 3.4. The bearing portions of the developer roll 3.4 and the toner equalization roll 5.6 are integrally accommodated in a holder 9 slidably provided on the left and right side frames 7.8 of the developer housing 2.

Tracking rolls 1O111, 12 and 3 are attached to the outside of the left and right side frames 7.8, respectively. This tracking roll 10°11.12.13 contacts the photoreceptor and rotates as the photoreceptor rotates.

At this time, the distance between the developing roll 3.4 and the photoreceptor 1 is 0.
, 05-0, 3ml11. Set screws 14.15 are in contact with the outer wall of the holder 9, and these set screws 141.15 are tightened with lock nuts 16.17 to keep the tracking roll 10 under the same pressure as the other three tracking rolls 11, 12.13. It is adjusted and fixed so that it is in contact with the photoreceptor 1.

On the other hand, the side frame 7.8 is 1. They are connected by elastically deformable tie bars 18.19 and held by outwardly projecting studs 20.21. This stud 20.21 is provided at a position where the moment considering the gravity of the two developer housings such as the developer roll 3.4 is equal.

In a conventional developing device, when the photoreceptor is stationary, four tracking rolls are in contact with the photoreceptor 1, and it appears that these four tracking rolls can follow the rotation of the photoreceptor. . However, a minute gap actually exists between the tracking roll and the photoreceptor.

However, in the developing device with the above structure, the elastically deformable tie bars can tolerate slight twisting, so if the developing device is held by studs at positions with equal moments as described above, the four tracking rolls will Due to minute torsional deformation of the device itself, it completely follows the photoreceptor regardless of whether the photoreceptor is stationary or rotating.

When the photoreceptor rotates, the tie bars 18.19 and the side frames 7.8 have solid internal friction, so vibrations of the developing device due to the rotation are absorbed. Further, the frequency at this time is within a range of several Hz at most, which is much smaller than the natural frequency of the developing device, so no resonance occurs.

2A and 2B show a second embodiment of the present invention, in which the set screw 14.1 of the above embodiment is used.
5 is replaced by springs 22,23. The springs 22 and 23 serve to press the holder 9, which integrally supports the developing roll and the uniformizing roll, toward the photoreceptor 1. As a result, the tracking roll attached to the outside of the side frame 7 comes into elastic contact with the photoreceptor. In this case, the spring constant needs to be set so that the frequency of the developing device supported by a spring with the tracking roll 10.13 as a fulcrum is sufficiently larger than the frequency caused by the rotation of the photoreceptor.

Specifically, since the frequency of the developing device due to the number of rotations of the photoreceptor is at most a few Hz, the frequency of the system described above is several 10 Hz.
A spring with a spring constant of several tens of Hz or more may be used.

[Brief explanation of the drawing]

1A and 1B are a side view and a front view of a first embodiment of the present invention, and FIGS. 2A and 2B are a side view and a front view of a side frame of a second embodiment of the present invention. . 1 photoreceptor, 2 developing device, 3.4 developing roll, 5.
6 Toner equalization roll, 7.8 Side frame, 9
Holder, 10.11.12.13 Tracking roll, 14.15 Set screw, 16.17 Lock nut, 18.19 Tie bar, 20.21 Stud, 2
2.23 Spring. N

Claims (1)

[Claims] Two developing rolls, two toner equalization rolls that are in pressure contact with the developing rolls, left and right side frames having bearings that rotatably support the four rolls, and a developing roll attached to the outside of the side frames. In a two-color color developing device for a non-magnetic component developer, which has four tracking rolls that are pressed against the photoreceptor to maintain a constant gap with the photoreceptor, the upper and lower ends of the left and right side frames are connected by an elastically deformable tie bar, and star rads for supporting the developing device are provided at positions of the left and right side frames such that the moments in the developing device are equal, and the developing roll and the equalizing roll are connected to each other by an elastically deformable tie bar. A two-color color developing device, characterized in that an adjustable means is provided for pressing only one bearing portion of the bearing portion toward the photoreceptor while maintaining the pressure contact distance between the developing roll and the uniformizing roll. .