JPH07261506A - Contact electrifier - Google Patents

Abstract

PURPOSE:To provide a contact electrifier capable of homogeneously and uniformly electrifying the whole surface of an electrified body face to the prescribed electrification potential with no electrification irregularity. CONSTITUTION:An electrifying member is constituted of brush structures 23, 24, 25, and it is fixed to holding members 22, 22F with an adhesive double coated tape 26. The electric unit resistance value of the holding member 22 is made smaller than the electric unit resistance value of the conducting substrate 24, and the conducting substrate 24 and holding member 22 are connected by two electric paths 30A, 30B. The effect of the voltage drop in the longitudinal direction of the conducting substrate 24 is removed, the dispersion of the applied voltage to the conducting cilium member 25 is reduced, and the whole surface of an electrified body face can be homogeneously and uniformly electrified to the prescribed electrification voltage Vc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact charging device formed so as to uniformly charge a surface of a member to be charged to a predetermined potential while the member for charging is in contact with the surface of the member to be charged.

[0002]

2. Description of the Related Art FIG. 10 shows a printing section 10 which forms a part of an electrophotographic apparatus, a copying machine, a facsimile or the like. In the figure, an image carrier 1 in which a photosensitive material is applied to the peripheral surface of a cylindrical body
A contact charging device 20, an exposure unit 2, a developing roller 3 forming a developing unit 3, a transfer unit 4, and a charge eliminator 6 are arranged around the center of the unit.

The peripheral surface of the image carrier 1, which is rotated in a perfect circle in the direction Q at a constant speed in the direction R, uniformly reaches a predetermined charging potential Vc (for example, -500V) when passing through the contact charging device 20. The exposed portion (electrostatic latent image) that is charged and subsequently drawn by using the exposure unit 2 has a predetermined potential Vim (for example, −50 V). Toner T is supplied from the developing roller 3 to the electrostatic latent image and developed into a toner image.

Then, this toner image is transferred and printed on the paper P which moves in the X direction when passing through the position facing the transfer device 4. After that, it goes to a fixing device (not shown). On the other hand, the peripheral surface of the image carrier 1 that has passed through the transfer device 4 is uniformly discharged to the initial potential Vin (for example, −50 V) by the charge remover 6 after the residual toner is removed by the waste toner blade.

By the way, the contact charging device 20 and the corona discharge type device shown in FIG. 10 are selectively adopted as the charging device. The former is often used because it has drawbacks such as space expansion, ozone generation due to corona discharge, and defective charging due to deterioration of the discharge wire.

Now, the contact charging device 20 shown in FIG.
It is composed of a charging roller (28, 29) forming a charging member and an ultra-high voltage power supply device 21 for applying an ultra-high voltage (for example, -5 kV) to the charging roller. The charging roller has a configuration in which a conductive portion 28 in which conductive particles are mixed in rubber is attached to the peripheral surface of a round shaft member 29, and the charging roller is formed so as to be rotated by the rotation of the image carrier 1. It is generally done.

Here, if the conductive portion 28 of the charging roller is brought into contact with the peripheral surface (charged body surface) of the image carrier (charged body) 1 which is surface-moved in the R direction at a constant speed, the charged body surface is moved. It can be charged to a predetermined charging potential Vc (for example, -500V).

[0008]

However, although it is possible to uniformly charge only when all the conditions are satisfied,
In the actual operation where the demand for higher image quality printing becomes stronger,
Stable satisfaction of all conditions is extremely difficult. That is, if the composition material of the charging member (28) lacks uniformity, for example, if there are variations in the distribution of conductive particles, the surface (1) to be charged cannot be uniformly charged. The same applies when the outer diameter is non-uniform in the length direction.

Further, it is difficult to assemble the charging member (28) so that the contact pressure with the surface (1) of the member to be charged falls within a predetermined range and to maintain the contact pressure state stably during operation. Therefore, if the contact pressure is too small, uneven charging occurs due to an increase in the non-charged portion, and if it is too large, direct charge injection occurs in addition to the original discharge action, and the charging voltage of the surface to be charged (1) increases. In addition to this, the surface of the body to be charged (1) and the charging member (28) are scratched, so high-quality printing cannot be guaranteed.

Further, when the surface moving speed of the charging member (28) is slowed down, the contact time at the same corresponding position of both (1, 28) becomes very long, so that the charge injection is further increased. In this case as well, the charging potential Vc (Vim) of the surface to be charged (1) rises and white streaks occur on the printing surface. On the other hand, if the surface moving speed of the charging roller 28 is made higher, the capacity of the motor increases and the power consumption increases, which is disadvantageous in the construction of the apparatus.

It is an object of the present invention to provide a contact charging device capable of uniformly and uniformly charging the entire surface of a member to be charged to a predetermined charging potential without uneven charging.

[0012]

The present invention was created based on the results of the following test studies. Defects due to the method of pressing the charging roller (28) in which rubber is mixed with conductive particles to the surface to be charged (1), that is, high quality printing is difficult due to uneven material and shape of the charging member, high cost, and difficult to manufacture and assemble. In order to eliminate damage to the surface of the body to be charged, we tried a charging member formed of a brush structure.

That is, as shown in FIGS. 1 and 2, the charging member has a brush structure 23 in which a conductive fibrous member 25 is densely planted on a conductive base material 24, and the brush structure 23 is a double-sided adhesive tape. 26 by using the smooth surface 22F of the holding member 22
Stuck to. Further, the holding member 22 for mounting the brush structure 23 in a predetermined posture is made of a conductive material, and
The conductive base material 24 and the high-voltage power supply 21 are connected to the holding member 22 and one end side of the holding member 22 (right end side in FIG. 2).
Was connected to one end side of the conductive base material 24 using an electric path 30 composed of a conductive adhesive layer formed by coating. Then, the high-voltage power supply device 21 is activated to apply a high voltage (-9
50V) was applied to charge the surface (1) to be charged.

According to this, the surface to be charged (1) could be uniformly charged to a predetermined charging voltage Vc (-500V). That is, the above-mentioned drawbacks caused by the method of pressing the charging roller against the surface of the body to be charged can be eliminated. Moreover, the contact pressure with the surface to be charged (1) can be easily adjusted only by changing the mounting position of the brush structure 23.

Further, in order to receive this and put it into practical use, FIG.
The trial was repeated by variously selecting the length L of the brush structure 23 shown in FIG. Then, it was recognized that the larger the length L, the more subtle variations occurred in the printed image. When the voltage at each place was measured to investigate the cause of this, when the length L was 240 mm, the conductive bristle member 2 at the right end in FIG.
5 is -950V, whereas the voltage applied to the leftmost conductive fibrous member 25 is -930V, which corresponds to the charging potential Vc of the surface (1) to be charged.
Was -480V with respect to -500V.

That is, it was assumed that the voltage drop in the longitudinal direction of the conductive substrate 24 had an effect, and the electrical resistance value per unit length (electrical unit resistance value) was analyzed. This conductive base material 24 is, for example, styrene-butadiene rubber (SBR), carbon, and a thickener (CMC) from the technical matters of implanting a large number of conductive fibrous members 25 and cost problems.
It is desirable to form it from a synthetic rubber material consisting of

Here, the composition of the conductive substrate 24 of the above experimental apparatus (FIGS. 1 and 2) is such that SBR: carbon is 6: 4 and a thickener (CMC) is added by 7.8%. Therefore, the electrical unit resistance value is 9 Ω-cm. Therefore, since the resistance value depends on the ratio of SBR and carbon, S
When the BR: carbon ratio was set to 4: 6, a resistance value of 1 to 2 Ω-cm was obtained, and the experiment was repeated. As a result, uneven charging could be eliminated, but as the operating time increased, the conductive substrate 2
4 caused a new problem of cracking.

When the ratio of SBR to carbon is 5: 5 or more, that is, carbon is 1/2 or more, it is recognized that cracking occurs when charging operation is carried out even if necessary and sufficient stirring is performed in the mixing stage. It was That is, reducing the electrical unit resistance value of the conductive base material 24 is unreliable from the viewpoint of cracking and cannot be put to practical use.

In the present invention, the charging member is formed of a brush structure 23 composed of a conductive base material 24 and a large number of conductive bristle members 25 planted therein, and the brush structure 23 is adopted. In this case, it is premised that the influence of the voltage drop of the conductive base material 24 cannot be eliminated and the influence thereof is great, and the voltage application of the high voltage power supply is applied so that the voltage drop of the conductive base material 24 does not appear as uneven charging. In order to achieve the above-mentioned object, the constitution is such that the substantial number or cross-sectional area thereof is increased in the longitudinal direction of the conductive substrate 24.

That is, the contact charging device according to the first aspect of the present invention is such that the charging member to which a voltage is applied is brought into contact with the surface of the charged body that is being surface-moved to uniformly charge the surface of the charged body to a predetermined potential. In the device, the charging member has a brush structure in which a conductive fibrous member is densely implanted on a conductive base material, and the brush structure is fixed to a holding member to which the voltage is applied by using a double-sided adhesive tape. The holding member is formed so that its electrical unit resistance value is smaller than that of the conductive base material, and the conductive base material and the holding member are separated from each other in the longitudinal direction of the conductive base material. It is characterized in that they are connected by a plurality of electric circuits.

Further, in the contact charging device according to the second aspect of the present invention, the charging member to which the voltage is applied is brought into contact with the surface of the charged body which is surface-moved to uniformly charge the surface of the charged body to a predetermined potential. In the device, the charging member has a brush structure in which a conductive fibrous member is densely implanted on a conductive base material, and the brush structure is fixed to a holding member to which the voltage is applied by using a double-sided adhesive tape. An electric path for forming the holding member with an electric unit resistance value smaller than that of the conductive base material and extending the conductive base material and the holding member in the longitudinal direction of the conductive base material. It is characterized in that they are continuously connected by.

[0022]

In the case of the invention of claim 1 having the above structure, the electric unit resistance value of the holding member is made smaller than the electric unit resistance value of the conductive base material forming the brush structure, and the holding member holds the conductive base material. Since the members are connected to each other by a plurality of electric paths spaced apart in the longitudinal direction of the conductive base material, the influence of voltage drop in the longitudinal direction of the conductive base material can be eliminated. Therefore, if a high-voltage power supply is applied to the holding member, a voltage can be applied uniformly to each conductive pili member. Therefore, the surface of the body to be charged can be uniformly and uniformly charged to the predetermined potential. The drawbacks of the charging roller method can be eliminated.

Further, in the case of the invention of claim 2, since the conductive base material and the holding member are continuously connected by an electric path extending in the longitudinal direction of the conductive base material, In addition to being able to achieve the same effect, it is possible to further reduce the variation in the applied voltage to each conductive pili member, and for example, if the double-sided adhesive tape is made conductive, the attachment to the holding member of the brush structure will be further improved. Can be simplified.

[0024]

【Example】

(First Embodiment) In the contact charging device 20, as shown in FIGS. 3 to 5, a charging member is formed of a brush structure 23 (24, 25) and a holding member 22 (22) using a double-sided adhesive tape 26.
F), the holding member 22 has an electrical unit resistance value smaller than that of the conductive base material 24, and the conductive base material 24 and the holding member 22 are plural (2).
(3), and the influence of the voltage drop in the longitudinal direction of the conductive base material 24 is eliminated to reduce the variation in the voltage applied to each conductive filament member 25, and the surface to be charged (1). Is uniformly and uniformly charged to a predetermined charging voltage Vc.

In this embodiment, as shown in FIG.
In the rotational direction R with respect to the surface to be charged (1), that is, in the surface movement direction, the amount of biting of the upstream conductive fibrous member 25U is large and the amount of biting of the downstream conductive fibrous member 25D is small to reduce the conductivity. It is formed so that the deformation of the pilus member 25 and the subtle jumping phenomenon of the upstream conductive pilus member 25U can be prevented and more uniform charging can be performed with high efficiency.

The printing unit 10 excluding the contact charging device 20
Since the basic structure of (1) is the same as that of the conventional example (FIG. 10), the same reference numerals are given to common components, and the description thereof will be simplified or omitted.

In FIG. 3, the conductive base material 24 forming the brush structure 23 is styrene butadiene rubber (SB).
R), carbon, and a thickening agent (CMC), and the ratio of SBR to carbon is selected to be such that cracking does not occur even if a long-time charging operation is performed. It is a synthetic rubber sheet type that has an electrical unit resistance value of.

Further, the material of each conductive bristle member 25 is R
EC-M1 (conductive rayon), resistance 10 ⁵ Ω, fiber diameter 6 denier (600D / 100F), 100,000 pieces /
Inch ² is uniformly planted in the conductive base material 24 with a planting density of ² .

The entire brush structure 23 is rich in electrical insulation, and the holding member 2 is sandwiched by the double-sided adhesive tape 26.
It is fixed to the second smooth surface 22F. The holding member 22
Is fixed to the main body case (not shown) in the posture shown in FIG. 5 with respect to the image carrier 1 forming the member to be charged.

The holding member 22 is formed by plating an L-shaped base material (for example, ABS or SZC) with zinc nickel, and has an electric unit resistance value of the conductive base material 24. It is considered to be much smaller than the value (9 Ω-cm). That is, the output voltage of the high-voltage power supply device 21 (-950 V in this embodiment) can be secured at any part.

The holding member 22 and the conductive base material 24 are
As shown in FIG. 3, the left and right are connected by two electric paths 30A and 30B made of a conductive adhesive layer. That is, the electric paths 30A and 30B that are spaced apart from each other in the longitudinal direction of the conductive base material 24.
And the above voltage (−950) is applied to each end of the conductive base material 24.
V) is applied.

This conductive adhesive layer (30A, 30B)
Is a mixture of a large number of conductive particles in the adhesive, and the holding member 2 is compared with the electric unit resistance value of the conductive base material 24.
Similar to the case of 2, it has a much smaller electric unit resistance value.

The brush structure 23 in this embodiment is also used.
The mounting posture of the image carrier 1 is as shown by the chain double-dashed line in FIG.
The amount of biting of the conductive fibrous member 25 to the peripheral surface, that is, the surface to be charged is set to be large on the upstream side and small on the downstream side in the surface moving direction (R direction). The bite amount is the amount by which the straight conductive bristle member 25 is pushed inward in the center Q direction from the peripheral surface when the image carrier 1 is assumed to be a non-resistive body.

Then, the conductive furrow member 25U on the most upstream side
Is the position aligned with the parallel line Z1 which is displaced by X1 from the normal line Z selected for layout reasons, and is the biting amount of Y1. That is, the brush structure 23
In relation to the size of the
Is to be able to contact the surface (1) to be charged. In other words, the brush structure 23 is designed to be easily enlarged so that a larger number of conductive bristle members 25D can be brought into contact with each other. In the case of this embodiment, Y1 is 1.00
mm and X1 are set to 0.99 to 1.00 mm. Therefore, Y2 is equal to the arc shape of the image carrier 1 (0.07 m
m) big.

According to the first embodiment having such a configuration, the high-voltage power supply device 21 is activated to apply the high voltage (-9) to the holding member 22.
50 V) is applied, and the image carrier 1 that forms a member to be charged
Is rotated at a constant speed in the R direction shown in FIG.

Then, the conductive base material 24 of the brush structure 23 is formed.
Through the holding member 22 having an extremely small electrical unit resistance value and the two electric paths 30A and 30B, a high voltage (-9
50V) is applied. Therefore, the voltage drop in the longitudinal direction based on the electrical unit resistance value (9 Ω-cm) of the conductive base material 24 is 1/2 as compared with the case of the experimental device (FIG. 2).
It should be as follows.

According to the actual measurement, the applied voltage at the central portion in the longitudinal direction of the conductive base material 24 having the length L (240 mm) can be kept at -945V, which is lower by -5V than the applied voltage at each end (-950V). did it.

Therefore, each conductive bristle member 25 of the brush structure 23 is halved the influence of the voltage drop in the longitudinal direction of the conductive substrate 24 (-950V) to (-945V).
Since a uniform voltage can be applied within the range, the entire surface of the surface to be charged (1) can be uniformly charged.
According to the actual measurement, the predetermined charging voltage Vc (-
It was confirmed that the image was charged to 500 V) and printed with high image quality.

Further, in this embodiment, the brush structure 23
All the conductive pili members 25 of the above conform to the surface (1) of the charged body. In other words, the curved surface is curved by an amount corresponding to each bite amount and comes into sliding contact with the surface (1) of the body to be charged. At this time, since the amount of biting of the upstream conductive fibrous member 25U having the highest charging efficiency is increased, a better sliding contact state can be established and highly efficient charging can be performed.

Thus, the deformation of each electroconductive fibrous member 25 and the subtle jumping phenomenon of the most upstream electroconductive fibrous member 25U can be prevented at once, and the upstream electroconductive fibrous member having a high charging efficiency. Since the sliding contact range of 25 U with respect to the surface of the body to be charged becomes long, the surface (1) of the body to be charged can be further uniformly and uniformly stably charged for a long period of time.

According to the first embodiment, however, the charging member is the brush structure 23 in which the conductive fibrous members 25 are densely planted on the conductive base material 24, and the brush structure 23 is adhered on both sides. It is fixed to the holding member 22 (22F) to which a voltage is applied by using the tape 26, the electric unit resistance value of the holding member 22 is formed smaller than the electric unit resistance value of the conductive base material 24, and the electric conductivity is obtained. Base material 24 and holding member 22
Since it is configured to be connected by a plurality of electric paths 30A, 30B spaced apart in the longitudinal direction of the conductive base material 24,
By removing the influence of the voltage drop in the longitudinal direction of the conductive base material 24, the voltage applied to each conductive fibrous member 25 (−950
V) can be reduced and the entire surface of the body to be charged (1) can be uniformly and uniformly charged to a predetermined charging voltage Vc (-500 V), high-quality printing can be performed, and the conductive base material 24 is also cracked. Since it does not exist, stable operation can be guaranteed for a long time.

Further, since the electric paths 30A and 30B are formed of the conductive adhesive layer, the connecting work is very simple and the number of connecting points can be easily increased or decreased.

(Second Embodiment) This second embodiment is shown in FIG.

According to the analysis through the first embodiment, if the variation in the voltage value in the longitudinal direction of the conductive base material 24 is within 20 V, the entire surface of the body to be charged (1) can be uniformly charged and the printed image can be obtained. Was also confirmed to be of high quality.

In the second embodiment, the brush structure 23 is further added.
The electrical unit of the conductive base material 24 is taken into consideration in consideration of the increase of the electrical unit resistance value and the fluctuation of the high-voltage power supply voltage due to the enlargement of the longitudinal dimension (L) of the conductive base material 24 and the increase in the freedom of selection of the conductive base material 24. In order to further wipe off the influence of the voltage drop of the resistance value, the conductive base material 24 and the holding member 22 are continuously connected by the electric path 31 extending in the longitudinal direction of the conductive base material 24.

The electric path 31 is formed of the same conductive adhesive layer as the electric paths 30A and 30B in the first embodiment. Thus, -950V can be held at any part of the conductive base material 24 in the longitudinal direction.

Therefore, according to this second embodiment, the first
In addition to the same operational effects as in the case of the embodiment, a predetermined voltage (-950) is applied to each conductive fibrous member 25.
Since V) can be applied equally, the brush structure 23 can be more uniformly charged, the brush structure 23 can be increased in size, the degree of freedom in selecting the conductive base material 24 can be easily increased, and the practical value can be further enhanced.

In the first and second embodiments described above,
The electric paths 30A, 30B and 31 are formed of a conductive adhesive layer. These electric paths are made of a material having an electric unit resistance value much smaller than the electric unit resistance value (9Ω-cm) of the conductive base material 24. I wish I had it. For example, a metal band, a conductive rubber or the like. Also, the connection method is not limited to the above-mentioned bonding method.

(Third Embodiment) This third embodiment is shown in FIG.
As shown in FIG. 8, the double-sided adhesive tape 26 is made electrically conductive, and the brush structure 23 (24) is fixed to the smooth surface 22F of the holding member 22 by using this conductive double-sided adhesive tape 26, and automatically in the longitudinal direction. The holding member 22 and the conductive base material 24 can be continuously connected in the longitudinal direction by the extending electric path (26).

That is, the tape 26B, the upper adhesive layer 26U, and the lower adhesive layer 26D shown in FIG. 8 which compose the double-sided adhesive tape 26 are more than the electric unit resistance value (9 Ω-cm) of the conductive substrate 24. It is formed to have a much smaller electrical unit resistance value.

Therefore, according to the third embodiment, the second
In addition to the same operational effects as in the case of the embodiment, the double-sided adhesive tape 26 is formed to also serve as an electric path, so that the assembly is very simple and the cost can be further reduced. Moreover, since the applied voltage in the width direction of the conductive base material 24 can be the same, no minute voltage difference is left.

(Fourth Embodiment) In the fourth embodiment, in contrast to the fixed brush structure 23 of the third embodiment,
As shown in FIG. 9, it is of a rotary type.

That is, the holding member 2 in the third embodiment.
2 is formed from a columnar body 22S2 and a shaft body 22S1, and the brush structure 23 is spirally wound around the columnar body 22S2 using the conductive double-sided adhesive tape 26, and the high-voltage power supply device 21 is connected to the shaft body 22S1. It has been configured.

Therefore, according to the fourth embodiment, the third
Similar to the case of the embodiment, in addition to the effect that the entire surface of the surface to be charged (1) can be charged uniformly and uniformly, the image bearing member is also provided similarly to the charging roller (28, 29) of the conventional example (FIG. 10). Since it can be moved relative to No. 1, it is possible to eliminate the drawbacks of the pressing method of the charging roller and facilitate the adjustment of the brush pressing force.

[0055]

As is apparent from the above description, claim 1
According to the invention, the charging member has a brush structure in which the conductive filament members are densely implanted on the conductive base material, and the brush structure is fixed to the holding member to which a voltage is applied by using a double-sided adhesive tape. Then, the electrical unit resistance value of this holding member is formed to be smaller than the electrical unit resistance value of the conductive base material,
Since the conductive base material and the holding member are connected to each other by a plurality of electric paths arranged in the longitudinal direction of the conductive base material, the influence of the voltage drop in the longitudinal direction of the conductive base material is eliminated. The unevenness of the voltage applied to each conductive filament member can be reduced to charge the entire surface of the body to be charged to a uniform and uniform predetermined charging voltage, high-quality printing can be performed, and the conductive base material may be cracked. Since it does not exist, stable operation can be guaranteed for a long time.

According to the second aspect of the present invention, the charging member has a brush structure in which the conductive fibrous member is densely implanted on the conductive base material, and the brush structure is applied with a double-sided adhesive tape to apply a voltage. Is adhered to the holding member to which is applied, the electric unit resistance value of the holding member is formed smaller than the electric unit resistance value of the conductive base material, and the conductive base material and the holding member are formed of a conductive base material. Since it is configured to be continuously connected by an electric path extending in the longitudinal direction of the material, the influence of the voltage drop in the longitudinal direction of the conductive base material is removed, and the entire surface of the body to be charged is claimed.
As compared with the case of the invention described above, the charging can be performed more uniformly and uniformly, and if the double-sided adhesive tape is made conductive, the attachment to the holding member having the brush structure can be further simplified.

[Brief description of drawings]

FIG. 1 is a front view for explaining the basic configuration of a brush structure used to create the present invention.

FIG. 2 is a side view for explaining a state in which the brush structure and the holding member are connected by an electric path in an experimental stage used for creating the present invention.

FIG. 3 is an external perspective view for explaining the first embodiment of the present invention.

FIG. 4 is likewise a front view.

FIG. 5 is likewise a side view.

FIG. 6 is an external perspective view for explaining the second embodiment of the present invention.

FIG. 7 is an external perspective view for explaining a third embodiment of the present invention.

FIG. 8 is likewise a view for explaining the conductive double-sided adhesive tape.

FIG. 9 is an external perspective view for explaining a fourth embodiment of the present invention.

FIG. 10 is a side view for explaining a conventional example.

[Explanation of symbols]

 1 image carrier (surface to be charged) 2 exposure means 3 developing roller 4 transfer device 6 static eliminator 10 printing unit 20 contact charging device 21 high voltage power supply device 22 holding member 22S1 shaft member (holding member) 22S2 columnar member (holding member) 22F Smooth surface 23 Brush structure (charging member) 24 Conductive base material 25 Conductive pili member 26 Double-sided adhesive tape 30A, 30B Electric path 31 Electric path

Claims (2)

[Claims] 1. A contact charging device for charging a charging member, to which a voltage is applied, to a surface of an object to be charged which has been surface-moved so as to uniformly charge the surface of the member to be charged to a predetermined potential. The base material has a brush structure in which conductive cilia members are densely implanted, and this brush structure is fixed to a holding member to which the voltage is applied by using a double-sided adhesive tape, and the electric unit resistance value of the holding member is fixed. Is formed to be smaller than the electrical unit resistance value of the conductive base material, and the conductive base material and the holding member are connected by a plurality of electric paths spaced apart in the longitudinal direction of the conductive base material. And a contact charging device. 2. A contact charging device for charging a charging member, to which a voltage is applied, to a surface of an object to be charged which has been surface-moved to uniformly charge the surface of the member to be charged to a predetermined potential. The base material has a brush structure in which conductive cilia members are densely implanted, and this brush structure is fixed to a holding member to which the voltage is applied by using a double-sided adhesive tape, and the electric unit resistance value of the holding member is fixed. Is formed to be smaller than the electric unit resistance value of the conductive base material, and the conductive base material and the holding member are continuously connected by an electric path extending in the longitudinal direction of the conductive base material, Contact charging device.