JPH0264681A - Measuring instrument for surface potential of photosensitive body in process unit - Google Patents

Abstract

PURPOSE:To constitute the title measuring instrument so that a distance between each sensor of a surface electrometer and the surface of a photosensitive drum is kept constant and to execute an exact measurement by using a comparatively inexpensive sensor by providing an operating means for moving a supporting member so that a roller and a cleaning means are brought into contact with and separated from the photosensitive drum. CONSTITUTION:By setting a process unit being in a state that it is assembled completely to a prescribed position of a device main body, a photosensitive drum is driven to rotate, and also, in a state that a roller 46 attached to a supporting member 44 and a cleaning means abut on the peripheral surface of the photosensitive drum 9, the surface potential of the photosensitive body is detected by a surface potential sensor 43. Accordingly, even if the rotation axis of the photosensitive drum 9 is eccentric, the supporting member 44 moves by following up a displacement in the radial direction of the peripheral surface of the drum caused by its rotation, the detection is always executed in a state that the roller 46 abuts on the surface of the photosensitive body 9, and a distance between the sensor 43 and the surface of the photosensitive body 9 is always kept constant. In such a manner, the measurement can be executed in a state that the process unit is assembled, and also, an exact inspection can be executed by an inexpensive structure.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an apparatus for measuring and inspecting the surface potential of a photosensitive drum provided in a process unit installed in a copying machine or the like.

(Prior Art) In recent years, for example, in electrophotographic copying machines, etc., consumables such as a photoreceptor, a main charging device, a cleaning device, etc. are integrated as a process unit, and these are attached to and removed from the copying machine body. Devices that can be freely attached are known.

In such a process unit, it is necessary to check whether the surface of the photoreceptor is properly charged in the main charging device, and therefore it is necessary to measure the surface potential of the photoreceptor.

(Problem to be Solved by the Invention) Conventionally, when performing such an inspection, in the assembly process of the process unit, the developing section, etc. of the process unit was removed and replaced with a surface electrometer (measuring jig). A method is used in which the process unit is installed in the main body of the copying machine, operated, and measured. However, according to such means, it is not possible to measure the process unit in a completely assembled state, and therefore inspection must be performed during the process of assembling the process unit, resulting in poor assembly efficiency of the process unit. Further, as sensors for detecting such surface potential, there are sensors whose measured value depends on the distance between the sensor surface and the surface to be detected, and sensors whose measured value is not related to the same distance. In general, sensors whose measured values are not related to distance are relatively expensive, and using such sensors for inspection will increase the cost of the product and measuring equipment, so even if the measured value is affected by the distance mentioned above, it is not cheap. It is desirable to use a suitable sensor.

For this reason, in the past, the distance from the photoreceptor surface was kept constant by increasing the accuracy of the mounting dimensions of the sensor, thereby making it possible to perform measurements using inexpensive sensors.

However, when using such an inexpensive sensor, the sensor must be accurately mounted at a predetermined distance from the photoconductor surface, and the parts must also have high dimensional accuracy, which increases the cost. There is an inconvenience that it is high.

In addition, even if the sensor is fixed at a position a predetermined distance from the surface of the photoreceptor and the measurement is performed in this way, if the rotation axis of the photoreceptor drum is eccentric or the radius of the drum is not aligned in the direction of the drum axis. If there are variations (for example, if the drum has a slightly truncated conical shape),
The distance between the photoreceptor surface and the sensor changes depending on the rotation of the drum or the installation location of the sensor, resulting in the inconvenience that accurate measurement cannot be performed.

(Objective) The present invention solves the above-mentioned conventional problems, and its object is to enable and easily measure the surface potential of a photoreceptor in a process unit when the process unit is completely assembled. In addition, by keeping the distance between the sensor and the photoconductor surface constant even if dust is attached to the photoconductor surface, accurate inspection of the photoconductor surface potential can be performed with an inexpensive structure. The purpose is to provide an inspection device that can perform the following tests.

(Means for Solving the Problems) The present invention is an apparatus for measuring and inspecting the surface potential of a photoreceptor drum provided in a process unit installed in an image forming apparatus, which supports the process unit in a predetermined position. A device main body for detecting the photoreceptor surface potential, a driving means for rotationally driving the photoreceptor drum, and a surface electrometer supported by the device main body. a support member on which a surface potential sensor is disposed in the axial direction of the photoreceptor drum; a roller attached to the support member and rotatable while in contact with the circumferential surface of the photoreceptor drum; a cleaning means that contacts the peripheral surface and is disposed on the support member upstream of the roller in the rotational direction of the photoreceptor drum, and a support member that is arranged so that the roller and the cleaning means come into contact with and separate from each other with respect to the photoreceptor drum. and an actuating means for moving the support member, and a distance between each surface potential set and the photoreceptor surface is maintained constant while the rollers of the supporting member and the cleaning means are in contact with the circumferential surface of the photoreceptor drum. It is.

Further, in the apparatus of the present invention, the cleaning means is an elastic body, and includes a thin plate-shaped cleaning member that is inclined downwardly toward the outside in the axial direction of the photoreceptor drum at the contact portion with the photoreceptor drum. It is characterized by the fact that

(Function) In this configuration, by setting the fully assembled process unit at a predetermined position in the main body of the apparatus, the photosensitive drum is rotationally driven, and the rollers and cleaning means attached to the support member are rotated. The surface potential sensor detects the surface potential of the photoconductor while it is in contact with the circumferential surface of the photoconductor drum. At this time, even if the rotation axis of the photoreceptor drum is eccentric, the support member moves to follow the radial displacement of the drum circumferential surface due to the rotation, and detection is performed with the rollers always in contact with the photoreceptor surface. Therefore, the distance between the sensor and the surface of the photoreceptor is always kept constant. Furthermore, even if the radius of the photoreceptor drum is not constant in the drum axial direction, the supporting member is tilted accordingly.
Both rollers are maintained in contact with both ends of the photoreceptor, and the distance is kept constant.

Further, even if dirt adheres to the circumferential surface of the roller contact track of the photosensitive drum, it is removed by the cleaning means upstream of the roller contact position, so that the distance is kept constant.

Further, the cleaning member in the cleaning means is an elastic body, and is in the form of a thin plate that slopes downward as it goes outward in the axial direction of the photoreceptor drum at the contact portion with the photoreceptor drum. They are guided by the slope of the cleaning member and fall to the bottom of the apparatus without being accumulated at the contact portion between the cleaning member and the photoreceptor drum.

(Embodiment) FIG. 1 shows the entire test and adjustment device for a process unit of a copying machine including a device for measuring the surface potential of a photoconductor according to an embodiment of the present invention, and FIGS. 2 and 3 show a device installed in the same device. The structure of the process unit is shown.

In Figures 1 to 3 above, 1 is the test device main body, 2
1 is a process unit, and the main body 1 is provided with a unit insertion hole 3 into which a process unit 2 is inserted. The main body 1 is provided with positioning pins 4.5 for setting the process unit 2 in a predetermined position (see the two-dot chain line in FIG. 1). A positioning bracket 7.8 with corresponding positioning holes is provided.

The process unit 2 includes a photoreceptor drum 9 that fits into a rotating shaft 6 provided approximately in the center of the unit case 10.
Around this drum 9, along the rotation direction,
A main charging section 11, a developing section 13, and a cleaning section 14 are provided. The developing section 13 includes a hopper section 16, a replenishment roller 17, an agitation roller 18, and a developing roller 19. The toner 15 filled in the hopper section 16 is supplied to the developing roller 19 side by driving the replenishment roller 17. It has become so. The cleaning section 14 includes a cleaning blade 20 and a spring 2 for applying a predetermined blade pressure to the cleaning blade 20.
It is equipped with 1st class. The main charging section 11 is, for example, a well-known corona discharger, and adjustment screws 111 (see the dashed line in FIG. 3) are provided at the front and rear parts (in the direction perpendicular to the plane of the paper in FIG. 3). By turning this adjustment screw 111, the height of the charging wire is adjusted.

The unit case 10 includes an adjustment screw 1!1 of the main charging section 11 and a spring 21 of the cleaning section 14.
Apertures 22 and 23 are formed facing each other, and an exposure opening 24 is formed facing a condensing lens 12 disposed on the main body 1 side, which will be described later. is provided with an opening 25 that exposes the drum downward.

In FIG. 2, reference numeral 10a is a handle used when attaching and detaching the process unit 2 to and from the copying machine or this apparatus.

On the other hand, apertures or openings are also formed on the wall surface of the unit insertion hole 3 on the side of the main body 1, facing the respective apertures 22, 23 and openings 24, 25. Further, on the outer body 1 facing the openings 22.23 and 24.25, a height adjustment driver 29, a blade pressure measuring device 30, and a photoreceptor drum 9 are provided with light from an exposure lamp 26 that irradiates the document. A condensing lens 12 for illuminating the surface of the photoreceptor drum 9, and surface electrometers 27 and 28 for measuring the surface potential of the photoreceptor drum 9 are provided.
29 and blade pressure measuring device 30 can be inserted into the process unit 2 through the openings 22, 23, respectively. The height adjustment driver 29 is installed at two locations, front and back (in a direction perpendicular to the plane of the paper in FIG. 1) corresponding to the adjustment screws 111 of the main charging section 11, and these adjustment screws 11
1 is rotated and driven up and down to automatically adjust.

Further, the blade pressure measuring device 30 measures the blade pressure by pressing the arm 141 that supports the blade about the fulcrum 142 with the spring 21 in a direction opposite to the blade pressing direction.

A shutter 31 is provided above the condensing lens 12 so as to open and close in the horizontal direction.
1, a solenoid 32 that opens and closes the shutter 3, and a shutter 3
A simulated contact glass G for reflecting the light from the exposure lamp 26 and guiding it to the condenser lens 12 is provided above the document placement surface. By opening and closing the shutter 31, the light from the exposure lamp 26 is switched between a state in which the photoreceptor drum 9 is irradiated and a state in which it is not irradiated, thereby making it possible to measure the bright potential and dark potential of the photoreceptor drum 9. It becomes. Although not shown, the exposure lamp 2
A part of the light 6 is also used to eliminate the charge on the photoreceptor drum 9. Further, a high voltage transformer (not shown) is provided on the main body 1 side to supply a high voltage to the main charging section 11 in the process unit 2.

One of the surface electrometers 27, which mainly constitutes the device for measuring the photoreceptor surface potential, has sensors disposed at both ends and at the center in the axial direction of the photoreceptor drum 9, as will be described in detail later. The overall amount of charge is measured. The other surface electrometer 28, which mainly constitutes the measuring device, includes a sensor that is operated in the axial direction of the photoreceptor drum 9, so that uneven charging in the axial direction of the photoreceptor drum 9 can be detected. It has become.

Are the detection signals from these surface electrometers 27, 28 and blade pressure measuring device 30 controlled? 'It1 part (control means) 34
The control section 34 receives these detection signals and an output signal from the operation section 33 provided on the outer surface of the main body 1, and controls the height adjustment driver 29, the solenoid 32, and the control section 34. A control signal is output to the display section 35. In this display section 35, based on the order from the control section 34, when the detected value deviates from a predetermined standard value, a lamp corresponding to the defective location lights up, and when the detected value is within the standard value, it is a non-defective product. The passing lamp will light up.

Further, although not shown, at the front in the insertion direction of the unit insertion hole 3 of the main body 1 (on the back side in the direction perpendicular to the paper surface in FIG. 1), there is a photoreceptor drum 9, an agitation roller 18 in the developing section 13, A drive mechanism (driving means) for driving the developing roller 19, replenishment roller 17, etc. is provided, and in order to determine whether there is any abnormality in the load of this drive system, it consists of a rotating pulse plate, a photo ink clubter, etc. A rotation measuring device is provided.

Next, the detailed structure of the surface electrometer 27 will be explained based on FIGS. 4 to 6.

As shown in FIGS. 4 and 5, the surface potential meter 27 includes a support member 44 that supports three surface potential sensors 41 to 43, and an actuation means 45 connected to this support member 44. There is. Among the surface potential sensors, the sensors 41 and 42 are disposed in housings 44a and 44b provided on the upper surface of both the front and rear outer sides of the support member 44.
3 is disposed in a housing 44c provided on the upper surface of the support member 44, and each of the sensors 41 to 43 faces the surface of the photoreceptor drum 9.

From both ends of the support member 44, roller support portions 44e protrude toward the photosensitive drum 9, and a roller 46 is rotatably supported at each end. These rollers 46 protrude from the surface of each sensor 41 to 43 toward the photoreceptor drum 9, and when these rollers 46 are in contact with the peripheral surface of both ends (non-image area) of the photoreceptor drum 9, , the distance between the surface of each sensor 41 to 43 and the surface of photoreceptor drum 9 is kept constant.

To explain in more detail with reference to FIG. 6, the rollers 46 are rotatably supported by a shaft 71 attached to the support member 44e, and two rollers 46 are disposed in the rotating direction of the photosensitive drum 9. The rollers 46, 46 have substantially the same configuration. And Koro 4
A cleaning means 81 is disposed on the upstream side of the photosensitive drum 9 rotation direction on the six orbits. The cleaning means 81 includes a mounting plate 82 mounted on the support member 44e, and a thin plate-shaped cleaning member 83 made of an elastic body mounted on the mounting plate 82.

The cleaning member 83 contacts the photoreceptor drum 9 on the contact trajectory of the roller 46, and as the photoreceptor drum 9 rotates, the cleaning member 83 removes dust such as chips mainly from tapping screws on the circumferential surface of the photoreceptor drum 9. remove. As shown in FIG. 5, the cleaning member 83 is inclined downwardly toward the outer side in the axial direction of the photosensitive drum 9 at the contact portion 88 to the photosensitive drum 9. As shown in FIG. Therefore, the removed dust is guided to the outside of the support member 44g, and accumulation of dust at the contact portion 88 is prevented.

Furthermore, each of the rollers 46 is provided with a roller cleaning means 84.

The roller cleaning means 84 includes an L-shaped mounting plate 86 attached to the support member 44e with screws 85, and a cleaning member 87 whose one end is attached to the mounting plate 86 and the other end is in contact with the circumferential surface of the roller 46.
It consists of This cleaning member 87 comes into contact with the circumferential surface of the roller 46 and removes dirt attached to the roller 46.
The peripheral surface of 6 is always maintained in a clean state. In addition, the cleaning member 8
7 has the same configuration as the cleaning member 83.

The actuation means 45 includes a wire 451, a tension disk 4
52 and a motor 453, and is connected to the support member 44 via a shaft 47 and a spherical sliding bearing 48. The wire 451 has one end fixed to the lower end of the shaft 47 and the other end fixed to the mounting plate 1a provided on the main body 1 side.

The tension disc 452 is connected to the drive shaft 453 of the motor 453.
a, and in the position shown by the solid line in FIG. 4, it is in a state where it lightly touches the wire 451, but when it is moved from this position to the position shown by the two-dot chain line in the same figure, the wire 451 is Pull in the direction perpendicular to the length. The motor 453 is fixed to the mounting plate 1a, and is driven and controlled by an output signal from the control section 34.

In the shaft 47, a bearing extending from the bottom wall of the main body 1 passes through the portion 1b, and this bearing is supported movably in the axial direction by a linear ball bearing 49 provided in the portion lb. . The spherical sliding bearing 48 is connected to the support member 44
The support member 44 is fitted into the lower part approximately in the center and connects the actuating means 45 and the shaft 47 with the support member 44, so that the support member 44 is supported with respect to the shaft 47 around one point on the central upper surface. It is rotatable around three axes, that is, it can be tilted in three directions. Since the support member 44 is tiltable in this way, even if the support member 44 is arranged with some deviation from the rotation axis of the photoreceptor drum 9, the rollers 46 and the cleaning means 81 can be moved to the photoreceptor drum without any inconvenience. The distance between the surface of each sensor 41 to 43 and the surface of photoreceptor drum 9 is kept constant.

A collar 47a is provided at the upper part of the shaft 47, and this collar 47a is provided at the top of the shaft 47.
A compression spring (holding means) 5 is installed between the receiver 7a and the upper surface of the portion 1b.
Similarly, a compression spring (holding means) 5 is interposed between the front and rear lower surfaces of the support member 44 and the upper surface of the receiving portion 1b.
1a and 51b are interposed. These springs 50,5
1a and 51b, the support member 44 is urged in the direction toward the photoreceptor drum 9, and unless the wire 451 is pulled by the tension disk 452, the roller 4
6 and the cleaning means 81 are held in contact with the circumferential surface of the photosensitive drum 9.

Further, a semicircular light shielding plate 454 is fixed to one side of the tension disc 452, and a light shielding plate 454 is placed at a position corresponding to this light shielding plate 454 on the mounting plate 1a.
A photo ink converter 455 consisting of a light-emitting element and a light-receiving element is fixed in such a manner that it is sandwiched therebetween. The light shielding Fi 454 rotates together with the tension disc 452 to communicate and block light between the light emitting element and the light receiving element, thereby changing the position of the tension disc 452, that is, the support member 44.
The location of is now detected.

Next, the detailed structure of the surface electrometer 28 will be explained based on FIGS. 7 and 8. This surface electrometer 28 is the seventh
As shown in the figure, a moving body 52 that moves in the axial direction of the photosensitive drum 9 is provided, and a surface potential sensor 53 is provided on this moving body 52.

As shown in FIG. 8, the moving body 52 includes a sliding portion 54,
A sensor mounting portion 55 and a tension adjustment portion 56 are fixed to both sides of the sliding portion 54, respectively.

The sliding portion 54 has a substantially U-shaped cross-sectional shape that opens at the bottom, and is fitted into a rail 63 formed on the main body 1 side. This rail 63 is formed on the upper part of the upright wall IC arranged along the axial direction of the photosensitive drum 9, and the sliding portion 54 can slide on this rail 63. The sensor attachment portion 55 is located directly below the photoreceptor drum 9 in the attached state, and the surface potential sensor 53 is attached to the sensor attachment portion 55 so as to face the circumferential surface of the photoreceptor drum 90.

The wire 59 is wound around pulleys 60 and 61 disposed at the front and rear of the main body 1, respectively, and then both ends of the wire 590 are connected via tension adjustment springs 57 and 58. The pulley 61 is attached to a mounting plate 61d extending to the rear of the main body 1, and is driven to rotate in both left and right directions by a suitable drive means such as a motor.

Due to this drive, the movable body 52 is pulled by the wire 59 and moves back and forth on the rail 63, and at the same time, the surface potential sensor 53 is scanned below the photosensitive drum 9 in its axial direction. The mounting positions of both ends of the wire 59 (front-rear direction and vertical direction) are adjusted and mounted so that the movable body 52 can move smoothly. Furthermore, since the mounting positions of both ends are shifted vertically, , wire 5
9. The tension disc can be easily attached by turning the screw at one end.

On the other hand, photo ink clubs 4 and 65 are attached to the longitudinal side surfaces of the upright wall IC at two locations in the front and rear directions. This photo ink club Taro 4.65 is equipped with a light emitting element and a light receiving element, and is attached to the side surface via a bracket 66 with the open parts of these elements facing the upper surface side of the main body 1 (upper side in FIG. 7). installed. On the other hand, a shielding plate 67 that blocks light between the elements extends downward from the tension adjustment section 56 of the movable body 52, and by shielding with this shielding plate 67, the movable body 52 in the front and rear is The stop position is detected and its reciprocating range is determined.

Next, measurement of the photoreceptor surface potential performed by this device,
The flow of this and other inspection operations will be explained based on the flowchart of FIG.

First, before use, the tension disk 452 of the surface electrometer 27 is at the position indicated by the two-dot chain line in FIG. It is held in a position that does not touch the surface. In this state, the process unit 2 is set at a predetermined position on the main body 10 (step S).

After the setting is completed, when the main switch of the operating section 33 is turned on (step S2), the blade pressure measuring device 30 is activated by the output signal of the control section 34, and the arm 141 supporting the blade 20 is moved in the biasing direction of the spring 21. By pressing in the opposite direction, the blade pressure is inspected (step S). Even after this inspection, the arm 141 continues to be pressed to separate the blade from the photoreceptor drum 9 and completely release the blade pressure. After that, the photosensitive drum 9 and the like are driven by the main motor and their torque is inspected (step SS). If any abnormality is found during these tests, it will be displayed on the display section 35 and the test operation will be immediately terminated.

After inspecting the rotational torque of the photoreceptor drum 9, etc.,
While the photoreceptor drum 9 continues to rotate, a high voltage is supplied to the main charging section 11 to charge the photoreceptor, and
The motor 4 of the surface electrometer 27 is activated by the output signal of the control unit 34.
Step S, ), tension circle +) to rotate 53.
Move i452 to the position indicated by the solid line in FIG. As a result, the tensile force of the support member 44 by the wire 451 is released, and the support member 44 is pressed against the photoreceptor drum 9 by the elastic force of the compression spring 50 and the like, and the roller 46 and the cleaning means 8
1 comes into contact with both ends of the photoreceptor drum 9. In this state,
Surface potential sensors 4 provided on both front and rear sides of the support member 44
1 and 42, the surface potentials of the front and rear parts of the photosensitive drum 9 are measured, and based on the measured values, the height of the wire is adjusted by driving the height adjustment driver 29 (step S).

At this time, for example, if the rotating shaft 6 of the photoreceptor drum 9 is eccentric, the portion of the circumferential surface of the photoreceptor drum 9 that the rollers 46 come into contact with will be displaced in the drum radial direction; Following this, the support member 44 and shaft 47 also move in the same direction, and since the support member 44 is receiving elastic force from the compression spring 50 etc., the rollers 46
The cleaning means 81 is held in contact with the photosensitive drum 9.

Further, the support member 44 is connected to the shaft 47 by a spherical sliding bearing 48, and is tiltable with respect to the axis of the photoreceptor drum 9. Therefore, if the radius of the photoreceptor drum 90 is not constant in the axial direction, for example, Even when the photoreceptor drum 9 has a slightly truncated cone shape, the support member 44 is inclined according to the circumferential surface of the photoreceptor drum 9.
The roller 46 and the cleaning means 81 are always kept in contact with the circumferential surface of the photosensitive drum 9. At this time, the dust on the circumferential surface of the photosensitive drum 9 is removed by the cleaning means 81, and the dust on the circumferential surface of the roller 46 is removed by the cleaning means 84. Therefore, while the photoreceptor drum 9 is rotating, the distance between the surface potential sensors 41 to 43 and the surface of the photoreceptor drum 9 is always kept constant.

In a specific example, the contact circumferential surface of the roller 46 on the photoconductor drum 9 is a non-image area at both ends of the photoconductor drum 9 circumferential surface. If this occurs, the photoreceptor will easily peel off, so the cleaning blade is shorter than the photoreceptor coated peripheral surface. Therefore, the adhesion of dust in this non-image area remains and spoils the aesthetic appearance. However, if the process unit is inspected by this device before being carried out as a product, dust in this non-image area of the photoreceptor drum can be removed, thereby improving the aesthetic appearance of the product.

After adjusting the height of the charger wire as described above, the surface potential is detected by the surface potential sensor 43 provided at the center of the support member 44, and the rotating photoreceptor drum 9 is charged in the circumferential direction. Detect unevenness (step S8
). If there is an abnormality in the value detected by the sensor 43, it is determined that there is an abnormality in the photoreceptor drum 9 (for example, uneven coating on the photoreceptor), and a message to that effect is displayed.

After completing the inspection using the surface electrometer 27 in this way,
The movable surface electrometer 28 is used to inspect uneven charging in the axial direction of the photoreceptor drum 9 (step S). That is, by driving the pulley 61 in both left and right directions, the movable body 52 is reciprocated in the back and forth direction below the photoreceptor drum 9, thereby scanning the surface potential sensor 53 in the axial direction of the photoreceptor drum 9. If there is an abnormality in the value detected by the sensor 53, it is determined that there is an abnormality in the main charging section 11 (for example, a charging failure due to the charger wire), and a display to that effect is displayed.

After completing the inspection as described above, step S
,. ), the tension disk 452 is moved to the position indicated by the two-dot chain line in FIG. This allows the support member 44 to
51 and separates from the photoreceptor drum 9. Thereafter, the pressure by the blade pressure measuring device 30 is released and the blade 20 is returned to its original pressed state (step 511). In this state, turn off the main switch (Step S1□), and remove the process unit 2 from the main body 1 (Step S1□).
13) Finish the operation.

In this embodiment, three compression springs 50, 51a, and 50b are provided as means for maintaining contact between the roller 46 and the cleaning means 81 and the photosensitive drum 9. - 43 is relatively lightweight and the dimension of the support member 44 in the drum axial direction is relatively small,
It is also possible to hold by a single spring 50. Further, in the light absorbing drum 9, the roller 46 and the cleaning means 81
There is no inconvenience in measurement as long as the contact area is set outside the range detected by each surface potential sensor, and the contact position is not strictly limited.

(Effects of the Invention) As described above, the present invention includes a surface electrometer for detecting the surface potential of a photoreceptor in the main body of the apparatus, and supports a process unit completely assembled at a predetermined position of the main body, thereby enabling inspection. Therefore, it is possible to facilitate the inspection work and improve the efficiency of assembling the process unit. Moreover, since the distance between each sensor of the surface electrometer and the surface of the photoreceptor drum is always kept constant by the rollers and cleaning means coming into contact with the surface of the photoreceptor, the distance to the surface to be detected is kept constant. Even when using a relatively inexpensive sensor whose measured value is affected by this, there is an advantage that the photoreceptor surface potential can always be accurately measured.

In addition, by providing a cleaning means, the process unit is constructed and assembled at low cost using screws and a resin housing, and even if dust such as chips from the tapping screws adheres to the surface of the photoreceptor, the cleaning means The distance between each sensor of the surface electrometer and the surface of the photoreceptor drum is always kept constant by cleaning the orbit of the roller in contact with the circumferential surface of the photoreceptor drum and by removing dust from the circumferential surface of the roller by the roller cleaning means. Therefore, it is possible to accurately measure the surface potential of the photoreceptor.

Furthermore, since the support member that supports each sensor can be tilted in any direction with respect to the rotation axis of the photoreceptor drum, if the outer diameter of the photoreceptor drum is not constant over the entire axial direction, that is, if the photoreceptor drum is Even if the shape is not perfectly cylindrical and out of roundness, or if the mounting position of the photoreceptor drum or surface electrometer is slightly misaligned, the support member tilts accordingly, allowing the rollers and the photoreceptor to Since contact with the body drum is maintained, normal measurements can be performed without any inconvenience.

Further, when the rollers come into contact with dust on the photoreceptor surface contact track, the dust is crushed and the photoreceptor is not damaged and its aesthetic appearance is not impaired.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of a copying machine process unit adjustment and testing apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view of the process unit, and FIG. 3 is a sectional view of the same unit.
Fig. 4 is a cutaway front view of a fixed surface electrometer in the above device, Fig. 5 is a view taken in the direction of arrow A in Fig. 4, Fig. 6 is a partially enlarged front view of Fig. 4, and Fig. 7 is a front view of the above device. 8 is a side view of the mobile surface electrometer in FIG. 7, FIG. 8 is a sectional view taken along the line ■-■ in FIG. 1... Entire test equipment, 2... Process unit, 6
...Rotating shaft, 9...Photosensitive drum, 27...Surface electrometer, 34...Control unit, 35...-Display unit, 41
~43...Surface potential sensor, 44...Supporting member, 4
5... Operating means, 46... Roller, 48... Spherical sliding bearing, 50.518.51b... Compression spring (holding means), 81... Cleaning means, 84... Roller cleaning means Figure Figure

Claims (2)

[Claims] (1) An apparatus for measuring and inspecting the surface potential of a photoreceptor drum provided in a process unit installed in an image forming apparatus, which comprises an apparatus main body supporting the process unit in a predetermined position, and rotating the photoreceptor drum. The surface potential meter includes a driving means for driving, and a surface potential meter supported by the device main body. a support member disposed on the support member; a roller attached to the support member and rotatable while in contact with the circumferential surface of the photoreceptor drum; a cleaning means disposed upstream of the roller in the rotational direction of the photoreceptor drum; and an actuating means for moving the support member so that the roller and the cleaning means come into contact with and away from the photoreceptor drum; Measuring the surface potential of a photoreceptor in a process unit characterized in that the distance between each surface potential sensor and the surface of the photoreceptor is kept constant while the rollers of the supporting member and the cleaning means are in contact with the circumferential surface of the photoreceptor drum. Device. (2) The cleaning means is an elastic body, and includes a cleaning member in the form of a thin plate that is inclined downwardly toward the outside in the axial direction of the photoreceptor drum at the contact portion with the photoreceptor drum. 2. The measuring device according to item 1, characterized in that: