JP2001034032A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device forming an image of excellent quality by rendering the detection result appropriate by stabilizing the output value from resist detecting means and density detecting means, and correctly adjusting the image forming position and the image density. SOLUTION: This image forming device is provided with processing cartridges 26Y, 26M, 26C and 26Bk incorporating plural image carriers on which the latent image is formed, an intermediate transfer belt 30 on which the visual image pattern is formed, and at least, either of a resist detecting sensor 50 detecting a position of the visual image pattern on the intermediate transfer belt 30 or a density detecting sensor detecting the density of the visual image on the intermediate transfer belt 30. And the image forming device is characterized by that the resist detecting sensor 50 and the density detecting sensor are separated from the intermediate transfer belt 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for forming a multicolor image on a sheet material, an electrophotographic system, an electrostatic recording system, or the like, which is used, for example, as a color copying machine or a color printer.

[0002]

2. Description of the Related Art Conventionally, various image forming apparatuses have been proposed, and among them, a color image forming apparatus is frequently used.

[0003] The color image forming apparatus is highly convenient, but has one aspect that the control at the time of image creation is more complicated than that of the monochrome image forming apparatus.

For example, four (plural) image carriers (hereinafter, referred to as image carriers)
Also referred to as a photosensitive drum. In a full-color image forming apparatus having an image forming apparatus, when the position of a sheet material on which an image is formed or the transfer image position on an intermediate transfer member deviates from an ideal position, in the case of a multicolor image, a shift in color image interval or In the case of a color image, the colors are different from each other, and when the color image is more severe, color shift occurs, and the quality of the image is significantly deteriorated.

Therefore, as a means for adjusting the color misregistration, a toner image pattern for each color is placed on a sheet material, a conveying means for conveying the sheet material, an intermediate transfer member, an image carrier, or the like. The color shift has been adjusted by reading the image pattern with a registration detection sensor.

That is, conventionally, the amount of deviation of each color toner from an image pattern on a conveying means, an intermediate transfer member, or an image carrier is detected with reference to a certain color reference, for example, an image pattern of yellow toner. By adjusting the position of a laser beam to be written on a photosensitive drum or changing the timing of writing an image for each color, the color misregistration is adjusted by moving a folding mirror in the scanner in accordance with the amount of deviation.

Further, when the toner density of each color on the sheet material or the intermediate transfer member is different, the color quality is similarly manifested as a difference in color tone, thereby deteriorating the image quality.

Therefore, similarly to the color misregistration, the toner image pattern for each color is placed on a sheet material, a conveying means for conveying the sheet material, an intermediate transfer member, an image carrier, or the like, and the density is adjusted. Reading was performed by a density detection sensor, and the developing bias of each color was adjusted to adjust the density.

[0009]

However, in the case of the above-described prior art, there is a problem that it may be difficult to accurately adjust the image forming position and the density as described above. Have a point.

That is, conventionally, a resist detecting sensor for detecting the adjustment of the image forming position and a density detecting sensor for detecting the image density are optical sensors, and are composed of an LED and a photodiode. Then, light is emitted from the LED to the toner pattern created on the image carrier, the intermediate transfer member, and the conveying means, and the reflected light of the toner pattern is received by the photodiode. Various controls are performed by detecting the amount and concentration.

At this time, as the number of sheets passed increases, toner and paper dust scattered in the apparatus adhere to the sensor surface, and the LED light amount and the output value of the photodiode change depending on the degree of dirt. Incorrect reading of the value or reading itself due to insufficient light intensity is not possible, which eventually causes color misregistration and a density difference for each color. In color images, image quality such as color difference is significantly reduced. .

In order to avoid the above problem, it is sufficient to set the light quantity input to the photodiode to a sufficient quantity. However, in order to secure the minimum light quantity on the photodiode, the sensor surface must be measured. Or LED
It is necessary to increase the amount of light of oneself.

In the former case, when the sensor surface and the object to be measured are brought close to each other, there is a possibility that the surface of the sensor will be damaged when the intermediate transfer member, the image carrier and the conveying means for forming the object to be measured (toner pattern) are replaced. There is a problem that there is.

Further, in the latter case, there is a problem that increasing the light amount of the LED causes an increase in the cost of the sensor itself.

The present invention has been made in view of the above circumstances,
Provided is an image forming apparatus capable of stabilizing output values from a registration detecting unit and a density detecting unit to obtain an appropriate detection result, correctly adjusting an image forming position and an image density, and obtaining a high-quality image. The purpose is to:

[0016]

In order to achieve the above object, an image forming apparatus according to the present invention comprises a plurality of image carriers on which a latent image is formed, and the latent image formed on the image carrier. An intermediate transfer body onto which a visible image pattern corresponding to is transferred, a resist detection unit for detecting the position of the visible image pattern on the intermediate transfer body, and a density of the visible image pattern on the intermediate transfer body. In the image forming apparatus provided with at least one of density detecting means for detecting, the resist detecting means and the density detecting means are provided with a first position for detecting the visible image pattern and a first position for detecting the visible image pattern. And a second position apart from the intermediate transfer member.

Also, an image carrier on which at least one latent image is formed and a visible image pattern is formed, a registration detecting means for detecting the position of the visible image pattern on the image carrier, and the image carrier An image forming apparatus comprising: at least one of density detection means for detecting the density of the visible image pattern on the carrier; wherein the resist detection means and the density detection means detect the visible image pattern And a second position separated from the image carrier with respect to the first position.

Further, a registration detecting means for detecting a position of a visible image pattern formed on a conveying means for conveying a sheet material on which an image is formed, and a density of the visible image pattern on the conveying means are detected. In an image forming apparatus provided with at least one of a density detection unit, the registration detection unit and the density detection unit are configured to detect a first position at which the visible image pattern is detected, and the first position with respect to the first position. And a second position apart from the transporting means.

Further, the case where the registration detecting means and the density detecting means are separated from each other is a case where the exterior of the image forming apparatus is opened.

Further, the case where the registration detecting means and the density detecting means are separated from each other is a case where a jam occurs in a sheet material.

Further, a holding means for holding at least one of the resist detecting means and the density detecting means is provided, and the separation is performed by moving the holding means.

Further, the movement of the holding means is a rotation about an axis, and the separation is performed by the rotation.

The image forming apparatus further includes a conversion unit for converting an operation of opening the exterior of the image forming apparatus to an operation of causing the holding unit to perform the movement when the exterior is opened. And

Further, when the converting means opens the exterior of the image forming apparatus, the converting means interlocks with the opening operation and pushes in a direction toward the inside of the image forming apparatus; A first cam member that moves in a direction substantially perpendicular to the internal direction of the image forming apparatus, and is provided on the holding unit, and is pushed by the first cam member to be pushed by the moving member; A second cam member for rotating the holding means about the axis.

An oscillating cam contacting the holding means;
The swing cam rotates when at least one of the case where the exterior of the image forming apparatus is opened and the case where the sheet material is jammed, so that the holding unit is centered on the shaft. It is characterized by turning.

Further, a driving source of the image forming apparatus main body is used as a driving source for rotating the swing cam.

A first rail provided on the holding means, an urging means for applying an urging force for rotating the holding means about the shaft, an intermediate transfer member or other consumables; And a second rail section fitted to the first rail section. The first rail section and the second rail are attached to and detached from the intermediate transfer member or other consumables. When the fitting with the part is released, the biasing means biases the holding means and rotates about the shaft, whereby the separation is performed.

Further, the holding means is detachable from the image forming apparatus.

Further, the resist detecting means and the density detecting means include a light emitting means and a light receiving means for receiving light from the light emitting means, and the position of the holding means is adjusted by the light emitted by the light emitting means. It is characterized in that the light is detected by the light receiving means receiving light.

Further, the present invention is characterized in that the presence or absence of an intermediate transfer member or other consumables is detected by the light receiving means receiving the light emitted by the light emitting means.

Therefore, according to the image forming apparatus of the present invention, the registration detecting means for detecting the position of the visible image pattern on the intermediate transfer member at the first position is separated from the intermediate transfer member by the second detection means. Since it is movable to the position, when detecting the position of the visible image pattern, the registration detecting means is moved to the first position by approaching the intermediate transfer body, for example, when replacing the intermediate transfer body, Since the registration detecting means is moved away from the intermediate transfer member to the second position, the output value of the registration detecting means can be stabilized to prevent color shift, and the intermediate transfer can be performed on the detection surface of the registration detecting means. It is possible to easily exchange the intermediate transfer member without damaging the body.

Since the density detecting means for detecting the density of the visible image pattern on the intermediate transfer member at the first position can be moved away from the intermediate transfer member to the second position, the visible image pattern can be moved. When the density is detected, the density detecting means is moved to the first position by approaching the intermediate transfer body. For example, when the intermediate transfer body is replaced, the density detecting means is separated from the intermediate transfer body and Because it is moved to the position of 2,
The output value of the density detecting means is stabilized, the image density can be easily adjusted, and the intermediate transfer body can be easily replaced without damaging the intermediate transfer body on the detection surface of the density detecting means. .

Further, the registration detecting means for detecting the position of the visible image pattern on the image carrier at the first position moves away from the image carrier to the second position. Is detected, the registration detecting means is moved closer to the image carrier and moved to the first position. For example, when the image carrier is replaced, the registration detecting means is separated from the image carrier and the second detection is performed. Since it is moved to the position, the output value of the registration detection means can be stabilized to prevent color misregistration,
Further, the image carrier can be easily replaced without damaging the image carrier on the detection surface of the registration detecting means.

Further, since the density detecting means for detecting the density of the visible image pattern of the image carrier at the first position moves away from the image carrier to the second position, the density of the visible image pattern is reduced. When detecting, the density detecting means is moved to the first position by approaching the image carrier. For example, when replacing the image carrier, the density detecting sensor is separated from the image carrier and moved to the second position. Since the image carrier is moved, the output value of the density detector is stabilized, the image density is easily adjusted, and the image carrier is easily replaced without damaging the image carrier on the detection surface of the density detector. Etc. can be performed.

Further, since the registration detecting means for detecting the position of the visible image pattern on the conveying means for conveying the sheet material at the first position moves away from the conveying means to the second position, the visible image pattern is moved. When detecting the position of the pattern, the registration detection means is moved to the first position by approaching the conveyance means. For example, when the conveyance means is replaced, the registration detection means is separated from the conveyance means and the second detection is performed. Since it is moved to the position, the output value of the registration detecting means can be stabilized to prevent color shift, and the transfer means can be easily replaced without damaging the conveying means on the detection surface of the registration detecting means. It can be carried out.

Further, since the density detecting means for detecting the density of the visible image pattern on the conveying means for conveying the sheet material at the first position moves away from the conveying means to the second position, the visible image When detecting the density of the pattern, the density detecting means is moved to the first position by approaching the conveying means,
For example, when replacing the transporting means, the density detecting means is moved away from the transporting means to the second position, so that the output value of the density detecting means is stabilized and the image density can be easily adjusted, and In addition, the transporting means can be easily replaced without damaging the transporting means on the detection surface of the density detecting means.

Further, when the exterior of the image forming apparatus is opened, the registration detecting means or the density detecting means is separated from the intermediate transfer member, the image carrier or the conveying means. The user is not particularly conscious of the operation of the means, and the work efficiency can be improved.

Further, when a jam occurs in the image forming apparatus, the registration detecting means or the density detecting means is separated from the intermediate transfer body, the image carrier and the transporting means. It is possible to avoid damage to the means, prevent contamination of the detection surface due to scattering of the developer, and perform the jam processing without the user being particularly conscious of the operation of the resist detection means and the density detection means. And work efficiency can be improved.

Further, since the holding means for holding at least one of the registration detecting means and the density detecting means is moved, for example, by rotating about an axis, the separation is performed. With a simple structure,
It can be performed more easily.

Further, when the exterior of the image forming apparatus is opened, the pushing member constituting the conversion means for converting the operation of opening the exterior to the operation for moving the holding means is a first cam. The first cam member pushes the member, and the second cam member is pushed by the first cam member, and the holding means rotates about the axis. This operation can be realized as a series of linked operations, and the operability can be improved, and the separation operation can be realized with a simple mechanism, so that an increase in the cost of the apparatus can be avoided.

Further, the swing cam rotates when at least one of the case where the exterior of the image forming apparatus is opened and the case where the sheet material is jammed,
Since the holding means rotates about the axis, the separation between the registration detecting means and the density detecting means held by the holding means can be more easily performed.

Further, since the driving source of the image forming apparatus main body is used as the driving source for rotating the oscillating cam, the driving source of the image forming apparatus main body is used as the driving source for rotating the oscillating cam. Even when the swing cam is rotated, the mechanism can be simplified and an increase in the number of parts can be suppressed.

Also, the holding means has a first rail portion,
A biasing means for applying a biasing force for rotating the holding means about an axis; and a second rail portion into which the intermediate transfer member or other consumables is fitted with the first rail portion. Therefore, the separation between the resist detection unit and the density detection unit held by the holding unit can be more easily performed.

Further, since the holding means is detachable from the image forming apparatus, maintenance can be easily performed when the detection surface or the like becomes dirty.

The resist detecting means and the density detecting means include a light emitting means and a light receiving means for receiving light from the light emitting means, and the light emitting means determines the position of the holding means and the presence or absence of an intermediate transfer member or other consumables. Since the light is emitted and detected by the light receiving means receiving the light, the position and the presence or absence can be grasped without adding a component, and the image forming apparatus can be appropriately operated.

[0046]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The materials, shapes, relative arrangements, and the like are not intended to limit the scope of the present invention only to them unless otherwise specified.

(First Embodiment) First, a first embodiment of the image forming apparatus according to the present invention will be described with reference to FIG. FIG. 1 shows a structural diagram of a first embodiment of an image forming apparatus according to the present invention.

The image forming apparatus shown in FIG. 1 is an image forming apparatus using four drums and an intermediate transfer belt.

In the image forming apparatus shown in FIG. 1, a plurality of cassettes 20 for stacking and storing recording sheets P as sheet materials are detachably mounted. The recording sheets P are fed by feed rollers 21. Will be fed.

The fed recording sheet P is separated one by one by a pair of retard rollers 22, and is conveyed to a pair of registration rollers 24 by conveyance rollers 23.

When the recording sheet P is conveyed, the registration roller pair 24 stops rotating, and the recording sheet P is skewed by being hit against the nip.

The process cartridges 26Y, 26M, 26C and 26Bk including the image bearing members are provided with cyan, magenta,
Yellow and black are arranged in parallel, and an optical scanning system 28Y, 28M, 28C and 28Bk is provided for each process cartridge.

After a toner image is formed on the image carrier for each color by the image signal, each toner is transferred onto the intermediate transfer belt 30 as an intermediate transfer member.

Thereafter, the recording sheet P is sent out at a predetermined timing to a secondary transfer roller 27 as a conveying means for conveying the sheet material, and the toner image on the intermediate transfer belt 30 is transferred onto the recording sheet P. After being fixed by the fixing device 25, the sheet is discharged by discharge rollers 29a and 29b and stacked.

In FIG. 1, reference numeral 50 denotes a registration detection sensor as registration detection means for detecting the position of an image on the intermediate transfer belt 30, and reference numeral 40 denotes a sensor plate as holding means, and reference numerals 3a and 3b denote registration plates. It is a housing axis. Here, the members shown in FIG. 1 will be described in more detail.

[Registration Detection Sensor 50] First, a more detailed structure of the image forming apparatus shown in FIG. 1 will be described with reference to FIG.
This will be described with reference to FIG. FIG. 2 is a partially enlarged view of the image forming apparatus shown in FIG. However, in FIG.
The same numbers are given to members similar to those shown in FIG.

FIG. 2 is an enlarged view of a portion of the registration detection sensor 50. The registration detection sensor 50 includes an LED 52 as a light emitting unit and a photodiode 53 as a light receiving unit.

In FIG. 2, however, the reason why the registration detecting sensors are described as 50 and 51 is that in FIG.
Is also shown.

The light emitted from the LED 52 is
The registration detection pattern 54 or the density detection pattern 55 as a visible image pattern on the intermediate transfer belt 30
And the light is incident on the photodiode 53, and the image forming position and the density are detected.

Next, a more detailed configuration of the registration detecting sensor 50 of the above-described image forming apparatus will be described with reference to FIG. FIG. 3 is a partial perspective structural view of the image forming apparatus shown in FIG.

As can be seen from FIGS. 1 and 3, the registration detection sensors 50 are arranged on the sensor plate 40 in a pair facing the intermediate transfer belt 30.

Then, the light emitted by the LED 52 is reflected by the registration detection pattern 54 (FIG. 2) formed on the intermediate transfer belt 30 and received by the photodiode 53 to detect the amount of reflection.

From the detected amount of reflection, the amount of displacement of the position with respect to the reference color is detected, and the writing timing for each color is changed to correct the color misregistration.

[Density Detection Sensor 51] Density Detection Sensor 5
As shown in FIG. 2, 1 has the same configuration as the registration detection sensor 50, and has an LED 52 and a photodiode 53.

As shown in FIGS. 1 and 3, the density detecting pattern 55 formed on the intermediate transfer belt 30 is disposed on the sensor plate 40 so as to face the intermediate transfer belt 30 similarly to the registration detection sensor 50. The light emitted from the LED 52 is reflected and received by the photodiode 53 to detect the density.

The optimum developing bias is determined from the detected density, and the fluctuation of the image density due to the deterioration of the photosensitive drum, the change of the environment and the deterioration of the toner is suppressed.

Next, the operation of each member shown in FIG. 3 will be described. 3, the registration detection sensor 50 and the density detection sensor 51 are disposed on the sensor plate 40 and are attached to the housing 1 (FIG. 1) via the sensor plate 40.

A cam link member A71 as a first cam member is provided on the housing 1 with a pushing member 72 as a pushing member.
And a cam link member B73 as a second cam member are attached to the sensor plate 40, respectively.

When the outer member is opened, the pushing member 7
2 moves the cam link member A71 toward the cam link member B73, and the cam link member A71
As a result, the sensor plate 40 rotates around the housing shaft 3. By this rotation, the registration detection sensor 50 and the density detection sensor 51 are separated from the intermediate transfer belt 30.

Conversely, when the exterior member is closed, the pushing member 72 is closed.
Is separated from the cam link member A71 and the cam link member A71
The sensor plate 40 is moved in the direction of the housing shaft 3 by the return spring 70 and separated from the cam link member B73, and the sensor plate 40 is
Close to zero. As described above, the return spring 70, the cam link member A71, the pushing member 72, and the cam link member B73 constitute a conversion unit.

With the above configuration, in the first embodiment of the image forming apparatus according to the present invention, when the exterior is opened when the intermediate transfer belt 30 is replaced, the registration detection sensor 50 and the density detection sensor 51 are attached. The sensor plate 40 is separated from the intermediate transfer belt 30, the replacement operation can be easily performed without damaging the intermediate transfer belt 30 on the sensor surface, and the sensor output value is stable because the sensor detection surface can be arranged close to the intermediate transfer belt 30. In addition, the image forming position and the image density can be appropriately adjusted, and a high-quality image can be obtained.

In this case, the same applies to the case where the opening / closing direction and the cam link mechanism are reversed.

(Second Embodiment) Next, an image forming apparatus according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 4 shows a partial perspective structural view of a second embodiment of the image forming apparatus according to the present invention. However, in FIG. 4, the same members as those shown in FIG. 1 are denoted by the same reference numerals.

Here, the second embodiment of the image forming apparatus according to the present invention is described.
This embodiment is different from the above-described first embodiment in the rotation operation of the registration detection sensor and the like and the structure accompanying the rotation operation, and the other operations and structures are the same, and the description thereof will be omitted.

In the second embodiment, as shown in FIG. 4, the registration detection sensor 50 and the density detection sensor 51 are disposed on the sensor plate 40 and are attached to the housing via the sensor plate 40.

Further, the housing receives a drive from a drive source (not shown) and rotates, and the rotating cam 7 is coaxial with the clutch 74.
5 are provided at positions where the swing cam 75 contacts the sensor plate 40.

When the opening / closing of the exterior member is detected, the swing cam 75 is rotated by connecting the clutch 74 to separate the sensor plate 40 from the intermediate transfer belt 30. Further, the same operation is performed when a jam is detected.

With the above configuration, in the second embodiment of the image forming apparatus according to the present invention, as in the first embodiment of the image forming apparatus according to the present invention, the intermediate transfer belt 30 is provided.
When the outer package is opened, the sensor plate 40 on which the registration detection sensor 50 and the density detection sensor 51 are disposed is separated from the intermediate transfer belt 30, and the replacement operation is easily performed without damaging the intermediate transfer belt 30 on the sensor surface. Since the sensor detection surface can be disposed close to the intermediate transfer belt 30, the sensor output value is stable, the image forming position and the image density can be appropriately adjusted, and a high-quality image can be obtained.

Further, since the sheet is separated at the time of a jam, it is possible to prevent the sensor surface from being stained by scattering of toner.

(Third Embodiment) Next, an image forming apparatus according to a third embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a partial perspective structural view of a third embodiment of the image forming apparatus according to the present invention. However, in FIG. 5, the same members as those shown in FIG. 1 are denoted by the same reference numerals.

Here, the third embodiment of the image forming apparatus according to the present invention will be described.
This embodiment is different from the above-described first embodiment in the rotation operation of the registration detection sensor and the like and the structure accompanying the rotation operation, and the other operations and structures are the same, and the description thereof will be omitted.

In FIG. 5, a registration detection sensor 50 and a density detection sensor 51 are arranged on a sensor plate 40 and are attached to the housing via the sensor plate 40.

The sensor plate 40 is provided with a rail portion 78 as a first rail portion, and the intermediate transfer belt 30 is provided with a rail member 77 as a second rail portion.

When the intermediate transfer belt 30 is inserted, the rail member 77 comes into contact with the rail portion 78 of the sensor plate 40, and the sensor plate 40 is moved to a normal position.

Conversely, when the intermediate transfer belt 30 is pulled out, the sensor plate 40 is rotated about the housing shaft 3 by the urging spring 76 as urging means urged by the urging spring plates 1a and 1b. And is separated from the intermediate transfer belt 30.

With the above configuration, the third embodiment of the image forming apparatus according to the present invention is similar to the first and second embodiments of the above-described image forming apparatus according to the present invention. When the belt 30 is replaced, the sensor plate 40 on which the registration detection sensor and the density detection sensor are arranged separates from the intermediate transfer belt 30 in conjunction with the operation of the intermediate transfer belt 30, and damages the intermediate transfer belt 30 on the sensor surface. The replacement operation can be easily performed without any trouble, and the sensor detection surface can be arranged close to the intermediate transfer belt 30, so that the sensor output value is stable, and the adjustment of the image forming position and the adjustment of the image density can be appropriately performed. High quality images can be obtained.

(Fourth Embodiment) Next, an embodiment in which functions are added to the above embodiments will be described with reference to FIG. FIG. 6 is a partial side view of an image forming apparatus according to a fourth embodiment of the present invention. However, in FIG. 6, the same members as those shown in FIG. 1 are denoted by the same reference numerals.

As shown in FIG. 6, this additional function is achieved by the registration detecting sensor 50 and the density detecting sensor 51 disposed on the sensor plate 40 in each of the first to third embodiments.
This is a function of causing at least one of the LEDs to emit light and recognizing the current position of the sensor plate 40 itself based on the amount of light reflected on the photodiode.

Further, if the position of the sensor plate 40 is detected by another simple sensor or switch, the intermediate transfer belt 30 can be detected.
Presence or the current position can be recognized.

Therefore, according to the fourth embodiment of the image forming apparatus according to the present invention, the same effects as those of the above-described first to third embodiments can be obtained, and a malfunction of the apparatus can be prevented and additional components can be added. You can grasp the position without doing.

In any of the first to fourth embodiments, the sensor plate 40 can be removed, and when the sensor surface becomes dirty, maintenance such as cleaning can be easily performed.

On the other hand, in each of the above-described embodiments, the pattern formed on the intermediate transfer belt 30 is detected to detect the image forming position and the density. However, the image forming apparatus according to the present invention employs such a case. It is not limited to
A pattern formed on another medium may be detected.

For example, a pattern formed on a photosensitive drum as an image carrier may be detected to detect an image forming position and a density.

(Fifth Embodiment) The image forming apparatus for detecting the pattern formed on the photosensitive drum as the image carrier and detecting the image forming position and density according to the present invention is described below. A fifth embodiment will be described below with reference to the drawings.

FIG. 7 shows a fifth embodiment of the image forming apparatus according to the present invention.
1 shows a structural diagram of an embodiment of FIG. However, among the members illustrated in FIG. 7, members that are the same as the members illustrated in FIG. 1 are given the same numbers, and detailed descriptions thereof are omitted.

As is apparent from a comparison between FIG. 7 and FIG. 1, the fifth embodiment of the image forming apparatus according to the present invention is different from the first embodiment of the above-described image forming apparatus according to the present invention. The difference is that the intermediate transfer belt 30 shown in FIG. 1 is replaced with a photosensitive drum 60 as an image carrier, and the process cartridges 26Y, 26M,
6C and 26Bk are replaced by process cartridges 62Y, 62M, 62C and 62Bk that do not include an image carrier. Other points are the same.

The operations of the sensor plate 40, the registration detection sensor 50, the density detection sensor, and the like are the same as the operations of the above-described first to fourth embodiments of the image forming apparatus according to the present invention. Therefore, a detailed description thereof will be omitted.

Therefore, in the fifth embodiment of the image forming apparatus according to the present invention, the same effects as those of the above-described first to fourth embodiments of the image forming apparatus according to the present invention can be obtained. At the same time, the image forming position and the density can be detected from the pattern formed on the photosensitive drum 60.

(Sixth Embodiment) Next, an image forming apparatus according to a sixth embodiment of the present invention will be described. In the sixth embodiment of the image forming apparatus according to the present invention, each of the above-described embodiments detects the image forming position and the density based on the pattern formed on the intermediate transfer belt or the photosensitive drum. The image forming position and the density are detected by a pattern formed on a conveying means such as a transfer roller for conveying the sheet material.

For example, in the case of the image forming apparatus having the structure shown in FIG. 1, the registration detecting sensor and the density detecting sensor are configured to detect the pattern formed on the secondary transfer roller 27 as the sheet conveying means. It may be provided. Of course, a pattern formed on another sheet material conveying means may be detected.

In this case, the pattern to be formed is preferably a pattern prepared for image formation position detection and density detection.

The other structures, operations, and the like are the same as those of the image forming apparatuses according to the above-described first to fifth embodiments, and thus detailed descriptions thereof will be omitted.

Therefore, in the sixth embodiment of the image forming apparatus according to the present invention, the same effects as those of the above-described first to fifth embodiments of the image forming apparatus according to the present invention can be obtained. At the same time, the image forming position and the density can be detected by the pattern formed on the conveying means.

[0104]

As apparent from the above description, according to the present invention, the registration detecting means and the density detecting means are separated from the intermediate transfer member, the image carrier and the conveying means, for example, in conjunction with the opening and closing of the exterior. Therefore, when performing the detection operation, the registration detection means and the density detection means are brought close to the intermediate transfer body, the image carrier and the conveyance means to maintain the detection accuracy, and the image forming position and the image density are appropriately adjusted, A high-quality image can be obtained, and other consumables such as the intermediate transfer body, the image carrier, and the transport unit can be easily replaced without damaging the surfaces of the intermediate transfer body, the image carrier, and the transport unit on the detection surface. An image forming apparatus capable of performing the above can be provided.

[Brief description of the drawings]

FIG. 1 is a structural diagram of a first embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a partially enlarged view of the image forming apparatus shown in FIG.

FIG. 3 is a partial perspective structural view of the image forming apparatus shown in FIG.

FIG. 4 is a partial perspective structural view of a second embodiment of the image forming apparatus according to the present invention.

FIG. 5 is a partial perspective structural view of a third embodiment of the image forming apparatus according to the present invention.

FIG. 6 is a partial side view of a fourth embodiment of the image forming apparatus according to the present invention.

FIG. 7 is a structural diagram of a fifth embodiment of the image forming apparatus according to the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 housing 1a, 1b biasing spring plate 3, 3a, 3b housing shaft 20 cassette 21 feeding roller 22 retard roller pair 23 transport roller 24 registration roller pair 25 fixing device 26Y, 26M, 26C, 26Bk including image carrier Process cartridge 27 Secondary transfer roller 28Y, 28M, 28C, 28Bk Optical scanning system 29a, 29b Discharge roller 30 Intermediate transfer belt 40 Sensor plate 50 Registration detection sensor 51 Density detection sensor 52 LED 53 Photodiode 54 Resist detection pattern 55 Density detection pattern 60 Photosensitive Drum 62Y, 62M, 62C, 62Bk Process Cartridge Not Containing Image Carrier 70 Return Spring 71 Cam Link Member A 72 Push Member 73 Cam Link Member B 74 Clutch 75 Swing Cam 76 Biasing Spring 77 Rail Material 78 Rail part P Record sheet

Claims (15)

[Claims] A plurality of image carriers on which a latent image is formed; an intermediate transfer member onto which a visible image pattern corresponding to the latent image formed on the image carrier is transferred; An image forming apparatus comprising: at least one of a resist detection unit that detects a position of the visible image pattern and a density detection unit that detects a density of the visible image pattern on the intermediate transfer body. The registration detecting means and the density detecting means are movable to a first position for detecting the visible image pattern and a second position separated from the intermediate transfer body with respect to the first position. An image forming apparatus comprising: 2. An image carrier on which at least one or more latent images are formed and a visible image pattern is formed, a registration detecting unit for detecting a position of the visible image pattern on the image carrier, and the image An image forming apparatus comprising: at least one of density detection means for detecting the density of the visible image pattern on the carrier; wherein the registration detection means and the density detection means detect the visible image pattern An image forming apparatus capable of moving to a first position to be moved and a second position apart from the image carrier with respect to the first position. 3. A resist detecting means for detecting a position of a visible image pattern formed on a conveying means for conveying a sheet material on which an image is formed, and detecting a density of the visible image pattern on the conveying means. In an image forming apparatus provided with at least one of a density detection unit, the registration detection unit and the density detection unit detect a first position at which the visible image pattern is detected and the first position with respect to the first position. An image forming apparatus, wherein the image forming apparatus is movable to a second position away from a conveying unit. 4. The image forming apparatus according to claim 1, wherein the registration detecting unit and the density detecting unit are separated from each other when the exterior of the image forming apparatus is opened. An image forming apparatus according to claim 1. 5. The apparatus according to claim 1, wherein the registration detecting unit and the density detecting unit are separated from each other when a jam occurs in a sheet material. Image forming device. 6. A holding device for holding at least one of the registration detecting device and the density detecting device, wherein the separation is performed by moving the holding device. The image forming apparatus according to claim 1. 7. The image forming apparatus according to claim 6, wherein the movement of the holding unit is a rotation about an axis, and the separation is performed by the rotation. 8. An image forming apparatus comprising: a conversion unit configured to convert, when the exterior of the image forming apparatus is opened, an operation for opening the exterior to an operation for causing the holding unit to perform the movement. The image forming apparatus according to claim 6, wherein: 9. A pushing member which pushes in an inward direction of the image forming apparatus in conjunction with the opening operation when the conversion means opens the exterior of the image forming apparatus; A first cam member that is moved in a direction substantially perpendicular to the internal direction of the image forming apparatus by a pushing movement of the moving member; and a first cam member that is provided on the holding unit and pushed by the first cam member, The image forming apparatus according to claim 8, further comprising: a second cam member configured to rotate a holding unit about the axis. 10. An oscillating cam contacting the holding means, wherein the oscillating cam is at least one of when an exterior of the image forming apparatus is opened and when a sheet jam occurs. The image forming apparatus according to claim 7, wherein the holding unit rotates about the axis by rotating in the case. 11. The image forming apparatus according to claim 10, wherein a driving source of the image forming apparatus main body is used as a driving source for rotating the swing cam. 12. A first rail provided on the holding means, an urging means for applying an urging force for rotating the holding means about the shaft, an intermediate transfer member or other consumables The first item provided on the article;
And a second rail portion to be fitted thereinto, wherein the intermediate transfer member or other consumables is attached and detached, and the first
When the fitting between the rail portion and the second rail portion is released, the urging means urges the holding means and rotates about the shaft, whereby the separation is performed. The image forming apparatus according to claim 7, wherein: 13. The image forming apparatus according to claim 6, wherein the holding unit is detachable from the image forming apparatus. 14. The resist detecting means and the density detecting means, comprising: a light emitting means; and a light receiving means for receiving light from the light emitting means, wherein the position of the holding means is changed by the light emitted by the light emitting means. The image forming apparatus according to claim 6, wherein the detection is performed by receiving light by a light receiving unit. 15. The image forming apparatus according to claim 14, wherein the presence or absence of an intermediate transfer member or other consumables is detected by receiving the light emitted by the light emitting unit by the light receiving unit.