JP2006251371A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of suppressing staining of the apparatus with toner scattered owing to peel discharge. <P>SOLUTION: The image forming apparatus is equipped with a toner sucking device 110 equipped with a discharge duct 111 connected to a discharge fan and a suction filter 112 for collecting scattered toner to suck toner scattered to below a delivery region D. Through the rotation of the discharge fan, an air flow which enables the suction filter 112 to suck air around the delivery region D is generated and the toner scattered owing to the peel discharge is collected by the suction filter 112 with the air flow. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile. More specifically, the present invention relates to an image forming apparatus that transfers a visible image onto both sides of a recording sheet such as a transfer sheet and fixes the visible images on both sides at the same time.

  Conventionally, a so-called switchback method and a one-pass method are known as methods for transferring an image onto both surfaces of a recording medium such as transfer paper. In the switchback method, first, a visible image is transferred to one surface of the transfer member that transfers a visible image on an image carrier such as a photosensitive member to the recording member through the recording member. Then, after the recording medium is inverted and switched back to the transfer means, the visible image is transferred to the other surface. On the other hand, the one-pass method forms images on both sides of the recording medium without switching back the recording medium by applying a visible image transfer process to both sides of the recording medium as a transfer means. The one-pass method is superior to the switchback method in the following points. That is, it is possible to avoid an increase in cost by providing a complicated mechanism for switchback and an increase in image formation time due to switchback. As an image forming apparatus that realizes such a one-pass method, for example, the one described in Patent Document 1 is known.

JP-A-1-209470

  FIG. 7 is a diagram illustrating a main part of the one-pass image forming apparatus. As shown in FIG. 7, the toner image carried on the first intermediate transfer belt 221 is transferred onto the upper surface of the recording medium P by the transfer roller 246, and the toner image carried on the second intermediate transfer belt 231 is transferred. The charger 247 transfers the recording material P to the lower surface, which is the surface of the member carrying the recording material. The recording body P on which the toner images are transferred on both sides in this manner is conveyed by the second intermediate transfer belt 234 that also serves as a recording member support member. Then, the recording material P is transferred from the second intermediate transfer belt 231 to the transport belt 251 as another member in the transfer area D. The conveying belt 251 is charged by being charged by the charge applying unit 257 disposed below the delivery area D, and the transferred recording medium P is electrostatically attached to the conveying belt 251. Then, it is conveyed to a fixing device (not shown).

  When the recording medium P moves away from the second intermediate transfer belt 231 and moves to the conveyance belt 251, there is a problem that toner electrostatically adhered to the lower surface of the recording medium P is scattered. This is because the recording medium P is charged by being charged by the transfer roller 246 and the transfer charger 247, so that when the recording medium P is separated from the second intermediate transfer belt 231, the recording medium P is placed between the recording medium and the second intermediate transfer belt 231. The potential difference becomes large, and peeling discharge occurs. It is considered that the toner adhering to the lower surface of the recording material P was scattered by receiving the impact of the peeling discharge directly. As described above, as a result of the toner adhering to the lower surface of the recording medium P being scattered, there is a problem that the periphery of the delivery area D where the recording medium P is transferred from the second intermediate transfer belt 231 to the conveying belt 251 is stained with toner. .

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus capable of preventing the apparatus from being soiled by toner scattered by peeling discharge.

In order to achieve the above object, according to the first aspect of the present invention, a toner image is transferred to one surface of the recording body in the course of conveying the recording body, and the other toner image is transferred to the other surface of the recording body. In an image forming apparatus that transfers and transfers a toner image onto both sides of the recording body, conveys the recording body onto which the toner image has been transferred to a fixing unit, and fixes the toner image on the recording body. At least the recording body of the recording body is carried in a delivery area where the recording body is delivered from a member carrying the recording body to another member while the recorded body is conveyed to the fixing unit. And a toner suction device for sucking the toner scattered from the surface on the member side.
According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the toner suction device is provided so as to face the surface of the recording member on the side of the member carrying the recording member. It is what.
According to a third aspect of the present invention, in the image forming apparatus of the first or second aspect, the suction force of the toner suction device is variable.
According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, at least the type of the recording body and the area ratio of an image formed on a surface of the recording body on the member side carrying the recording body. One feature is that the suction force of the toner suction device is changed.
According to a fifth aspect of the present invention, in the image forming apparatus according to the third or fourth aspect, when an image is not formed on the surface of the recording member on the side of the member carrying the recording body, the operation of the toner suction device is performed. It is characterized by stopping.
According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the third to fifth aspects, the suction force of the toner suction device while the front end of the recording body passes through the delivery area is expressed by the front end of the recording body. Is weaker than the suction force until the trailing edge of the recording material has passed through the delivery area after passing through the delivery area.
According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the third to sixth aspects, the toner image is transferred by applying a charge having a polarity opposite to the charge carried on the recording paper by the charge applying means. The recording member is provided with a conveying member that conveys the recording medium to the fixing unit, and the amount of charge applied to the conveying member is changed based on the suction force of the toner suction device.
According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the first to seventh aspects, the toner suction device includes a filter for collecting toner, and the filter is detachable from the toner suction device. It is characterized by being comprised.

  According to the first to eighth aspects of the present invention, the toner scattered directly from the surface of the member carrying the recording body in response to the impact of the peeling discharge generated when the recording body leaves the member carrying the recording body. By sucking the toner with the toner suction device, the device can be prevented from being contaminated by the scattered toner. Further, by providing a toner suction device in a delivery area where the recording medium is delivered from the member carrying the recording body to another member, the toner scattered by the peeling discharge can be efficiently sucked. Thereby, it is possible to suppress the periphery of the delivery area of the apparatus from being contaminated by the scattered toner.

Embodiments in which the present invention is applied to an image forming apparatus will be described below.
FIG. 1 shows a full-color printer 100 capable of duplex printing by an electrophotographic method as an image forming apparatus according to the present embodiment.
In the printer main body 100 shown in FIG. 1, the first image unit 20 is arranged at the upper part and the second image unit 30 is arranged at the lower part with the recording material conveyance path 43A as a boundary. The first image unit 20 includes a first intermediate transfer belt 21 as an image carrier that moves endlessly in an arrow direction, and the second image unit 30 includes a second intermediate transfer belt 31 as an image carrier that moves endlessly in an arrow direction. I have. Four first image forming units 80 </ b> Y, 80 </ b> C, 80 </ b> M, and 80 </ b> K serving as toner image forming units are disposed on the upper stretched surface of the first intermediate transfer belt 21. On the other hand, four second image forming units 81Y, 81C, 81M, 81K, which are toner image forming means, are arranged on the upper stretched surface of the second intermediate transfer belt 31. Y, C, M, and K along the numbers of the first and second image forming units correspond to the colors of the toner to be handled. Y is yellow, C is cyan, M is magenta, and K is black. Means. Similarly, Y, C, M, and K are provided along the photosensitive member 1 provided in the first and second image forming units and rotating together with the first intermediate transfer belt 21 and the second intermediate transfer belt 31. The photoreceptors 1Y to 1K are arranged at the same interval in each image forming unit, and at least at the time of image formation, are in contact with a part of the stretched portion between the intermediate transfer belts 21 and 31, respectively. These contacting surfaces are referred to as a first image receiving surface F1 and a second image receiving surface F2, respectively, and their positional relationships are shown in FIG.

As shown in FIG. 2, when the angle of the angle including the first and second image forming units among the angles formed by the first image receiving surface F1 and the second image receiving surface F2 is α, the value of α is 180. It should be larger than 270 ° and smaller than 270 °.
Further, a configuration is adopted in which at least a part of the horizontal projection surface of the first intermediate transfer belt 21 at the upper portion and the horizontal projection surface of the second intermediate transfer belt at the lower portion overlap each other. That is, the shape is such that the second intermediate transfer belt in the lower part is recessed below the first intermediate transfer belt in the upper part. By adopting such a configuration, a more compact layout is possible in the lateral direction.

Although the toner colors to be handled are different, the configurations of the first image forming units 80Y, 80C, 80M, and 80K are the same. Therefore, the configuration of the first image forming unit 80 will be described with reference to FIG.
In FIG. 3, when the printer main body 100 is in operation, a cylindrical photosensitive member 1 that is rotatably supported by a drive source (not shown) so as to rotate in the direction of the arrow is disposed. Then, an image forming member such as a scorotron charger 3, an exposure device 4, a developing device 5, a cleaning device 2, and a photostatic device Q, which are charging means according to an electrophotographic process, an electric potential sensor S1, and an image around the photoreceptor 1. A sensor S2 is provided.
The photoreceptor 1 is obtained by forming an organic photosensitive layer (OPC), which is a photoconductive substance, on an aluminum cylinder surface having a diameter of about 30 to 120 mm. A photoconductor on which an amorphous silicon (a-Si) layer is formed can also be used. A belt-like photoreceptor can also be employed. The cleaning device 2 includes a cleaning brush 2a, a cleaning blade 2b, and a recovery member 2c, and removes and recovers foreign matters such as toner remaining on the surface of the photoreceptor.

  The exposure device 4 scans the light corresponding to the image data for each color on the surface of each photoreceptor 1 that has been uniformly charged by the charging means, and forms an electrostatic latent image. The exposure apparatus 4 in the illustrated example is an exposure apparatus that includes an LED (light emitting diode) array and an imaging element as light emitting elements, but uses a laser light source, a polygon mirror, etc., and beam light modulated according to image data to be formed. It is also possible to adopt a laser scanning type exposure apparatus. In addition to the charger 3, a type that makes contact with the surface of the photoreceptor 1, such as a charging roller, can be used as the charging means.

The development at this time is a development system that employs a two-component developer composed of toner and carrier. The electrostatic latent image for each color formed on the surface of each photoconductor 1 by the exposure device 4 with respect to the negatively charged photoconductor 1 is a toner of a predetermined color having the same polarity (negative polarity) as the charged polarity of the photoconductor. Developed to become a visible image. So-called reversal development is performed.
The yellow (Y), cyan (C), magenta (M), and black (K) toners are detected by the magnetically permeable toner detecting means 5e when consumed by the developing device that handles each color. Then, toner of each color is supplied from a toner cartridge (not shown) inside the printer main body 100 to each developing device 5 by a supply unit (not shown). As this supply means, a system using a known MONO pump can be adopted. According to this method, there are few restrictions on the installation location of the toner cartridge, which is advantageous for space allocation inside the printer main body. Further, since the toner can be replenished in a timely manner, it is not necessary to provide a large toner storage space in the developing device, and the developing device can be downsized.

  The developing device 5 is provided with screws 5c and 5d for stirring and conveying the toner and carrier. When the developing device 5 is attached to the printer main body 100, one end of the toner replenishing means is connected to a part of the screw 5d. The toner is supplied to the developing roller 5a rotating in the direction of the arrow by the screw 5c, but the thickness of the toner layer on the surface of the developing roller 5a is regulated to a predetermined thickness by the blade 5b. The developing roller 5a is a cylinder made of stainless steel or aluminum, and is supported by the frame of the developing device 5 so as to be rotatable and a distance from the photoreceptor is properly secured, and a predetermined magnetic force line is formed inside. Has a magnet. As the toner, a spherical or irregular toner obtained by a conventionally known method is used.

Since the second image forming units 81Y, 81M, 81C, and 81K used in the second image unit 30 have the same configuration, the second image forming unit 81 will be described with reference to FIG.
The second image forming unit 81 shown in FIG. 4 has the same constituent members as the first image forming unit 80, but the rotational direction of the photosensitive member 1 is different from that of FIG. However, they are mutually shaped with respect to the y-axis passing through the rotation axis 1a of the photosensitive member 1 indicated by an arrow in the drawing. This shape is an important matter although it is related to the arrangement of image forming members provided around the photoreceptor 1. That is, consideration is given to a method of connecting a connecting portion with the printer main body 100, for example, a connecting portion with a driving means, an electrical connecting portion, a toner supplying portion, and a toner discharging portion. Thereby, the first image forming units 80Y, 80M, 80C, and 80K can be compatible with the second image forming units 81Y, 81M, 81C, 81K. Therefore, it is not necessary to manufacture the developing device, the cleaning device, and the parts individually for the first image forming unit and the second image forming unit, and the efficiency in manufacturing parts and managing parts is high, and the overall cost can be reduced. It is peeled off.
There are the following two conditions that can be used in the first image unit 20 and the second image unit 30 in the form of an axial object with the first and second image forming units as the center of the y-axis. As a first condition, a peripheral surface on which no member for image formation is provided around the photosensitive member 1 is secured, that is, a wide range in which the intermediate transfer belt can contact is secured. It is done. The second condition is that the arrangement angle between the image receiving surface F1 of the first intermediate transfer belt 21 and the image receiving surface F2 of the second intermediate transfer belt 31 is appropriate.

The first condition and the second condition will be described with reference to FIGS. 3 or 4, the intermediate transfer belt 21 or 31 can be installed between the arrows A1 and A2. That is, the A1 side is the developing device 5, and the A2 side is that the intermediate transfer belt can be installed in a range where the belt does not contact the cleaning device 2. The inclusion of the second image bearing belt 31 in FIG. 3 shows an intermediate transfer belt on which the target image forming unit can be arranged with respect to the y axis including the rotation axis 1 a of the photoreceptor 1.
If the image forming unit 80 is turned upside down with respect to an axis orthogonal to the y axis and used as the image forming unit 81, the toner is stirred at least in the developing device 5 due to the influence of the earth's gravity and the toner on the developing roller 5a. Conditions such as replenishment are different. As a result, the members of the image forming unit 80 must be optimized, and parts cannot be shared.

  As shown in FIG. 2, the angle α is greater than 180 degrees and less than or equal to 270 degrees as a positional relationship between the image receiving surface of the first image carrying belt 21 and the image receiving surface of the second image carrying belt 31. When the angle is preferably from 210 degrees to 255 degrees, the first image carrier belt shown in FIG. 3 and the second image carrier belt shown in FIG. 4 can be used as the image forming unit. That is, it is possible to avoid an image forming unit that makes it impossible to share parts as described above.

Further, as shown in FIG. 2, since the recording medium conveyance path can be secured almost horizontally and linearly above the second image forming unit 81, the recording medium is excellent in conveyance and reliability, and the entire printer is integrated. It becomes good.
In particular, the first image carrying belt is stretched horizontally and flatly, and the second intermediate transfer belt is stretched long and inclined in the vertical direction. The space in the height direction of the intermediate transfer belt is increased. However, as shown in FIGS. 3 and 4, the image forming unit has a vertical dimension with respect to the horizontal dimension by ensuring a wide range in which the image forming unit can contact the intermediate transfer belt. Is a short configuration. For this reason, in the second image unit, the image forming unit is disposed obliquely in the vertical direction with respect to the first image unit in which the image forming unit is disposed substantially horizontally. In addition, the interval between the image forming units can be set short, and the space in the height direction of the second image unit can be saved. As a result, the degree of freedom in the layout in the height direction is increased, so that the recording medium conveyance path can be set to an ideal height considering operability, a paper feeding device, and a post-processing device (not shown). .

In addition, since the sheet feeder having the same height as that occupied by the second intermediate transfer belt can be installed side by side, it is possible to install a sheet feeder that can accommodate a large number of recording media. In addition, the sheet feeding surface on the upper surface of the sheet feeding device and the recording medium conveying path can be made substantially the same height, and the sheet feeding / conveying reliability of the recording medium can be secured.
As described above, the image forming units 80 and 81 have many common points due to the arrangement of the image forming apparatus around the photosensitive member and the arrangement of the intermediate transfer belt, that is, the realization of the second condition. But it is very advantageous.

Next, the intermediate transfer belt will be described. The first intermediate transfer belt 21 as the first toner image conveying belt is supported by a plurality of rollers 23, 24, 25, 26 (two), 27, 28, 29 and travels in the direction of the arrow. The first image forming units 80Y to 80K are provided below the photoreceptors 1Y, 1C, 1M, and 1K. The first intermediate transfer belt 21 is endless, and is stretched and arranged so that a part of each photoconductor after the developing process comes into contact. In addition, a primary transfer roller 22 is provided on the inner peripheral portion of the first intermediate transfer belt 21 so as to face the photoreceptors 1Y, 1C, 1M, and 1K.
A cleaning device 20 </ b> A is provided on the outer periphery of the first intermediate transfer belt 21 at a position facing the roller 23. The cleaning device 20 </ b> A wipes away unnecessary toner remaining on the surface of the first intermediate transfer belt 21 and foreign matters such as paper dust.
Members related to the first intermediate transfer belt 21 are integrally configured as the first image unit 20 and can be attached to and detached from the printer main body 100.
The first intermediate transfer belt 21 is a medium resistance belt of 10 ⁸ to 10 ¹⁰ [Ω · cm].

On the other hand, the second intermediate transfer belt 31 as the second toner image conveying belt is supported by a plurality of rollers 33, 34, 35, 36 (two), 37, 38 and travels in the direction of the arrow. The second image forming units 81Y to 81K are provided in contact with the photoreceptors 1Y, 1C, 1M, and 1K. The second intermediate transfer belt 31 is endless, and is stretched and arranged so that a part of each photoconductor after the developing process comes into contact. A primary transfer roller 32 is provided on the inner peripheral portion of the second intermediate transfer belt 31 so as to face the photoreceptors 1Y, 1C, 1M, and 1K.
A cleaning device 30 </ b> A is provided on the outer periphery of the second intermediate transfer belt 31 at a position facing the roller 33. The cleaning device 30 </ b> A wipes off unnecessary toner remaining on the surface of the intermediate transfer belt 31 and foreign matters such as paper dust.
The second intermediate transfer belt 31 is a medium resistance belt of 10 ⁸ to 10 ¹⁰ [Ω · cm].
Members related to the second intermediate transfer belt 31 are integrally configured as the second image unit 30 and can be attached to and detached from the printer main body 100.

Further, a first secondary transfer roller 46 is provided on the outer periphery of the first intermediate transfer belt 21 in the vicinity of the support roller 28. The secondary transfer roller 46 is made of a metal roller serving as a core metal and is coated with conductive rubber, and a bias is applied to the core metal part from a power source (not shown). Carbon is dispersed in the conductive rubber, and the volume resistance is adjusted to about 10 ⁷ Ωcm. By applying +50 [μA] to the first secondary transfer roller 46 while passing the recording medium P between the first intermediate transfer belt 21 and the secondary transfer roller 46, the first image carrying belt 21 is carried. The toner image is transferred to the recording material P.

  A transfer charger 47 serving as a second secondary transfer unit is provided on the outer periphery of the second intermediate transfer belt 31 and in the vicinity of the support roller 34. The transfer charger 47 is a known type, and a thin wire of tungsten or gold is used as a discharge electrode, held by a casing, and a transfer current is supplied to the discharge electrode from a power source (not shown). By supplying a transfer current while passing the recording medium P between the second intermediate transfer belt 31 and the transfer charger 47, an image by the toner carried by the second image carrying belt 31 is transferred to the recording medium P. The polarity of the transfer current supplied to the transfer charger 47 is a positive polarity opposite to the polarity of the toner, and a current of 200 [μA] is applied to the transfer charger 47.

  On the right side of the printer main body 100, a paper feeding device 40 that accommodates the recording material P is provided. Paper feed device (tray) 40a containing a large number of recording media in a plurality of stages, for example, the upper stage, and three stages of paper feed cassettes 40b, 40c, and 40d below each are pulled out to the front (operation surface side) perpendicular to the paper surface. It is arranged to be possible. Different types of recording media P are stored in the paper feed tray 40a and the paper feed cassettes 40b, 40c, and 40d, respectively. Of these, the uppermost recording medium is selectively fed and separated by the corresponding paper feeding / separating means 41A to 41D, and only one sheet is reliably fed by the plurality of conveying roller pairs 42B to the recording medium conveying paths 43B and 43A. Sent to.

  A pair of registration rollers 45 is provided in the recording material conveyance path 43A in order to take a feeding timing for sending the recording material P to the secondary transfer position which is the first and second transfer positions. Further, a lateral registration correcting mechanism 44 for setting the position perpendicular to the conveyance direction of the recording medium to a normal position is provided in the recording medium conveyance path 43A. The lateral registration correction mechanism 44 includes the following. The recording medium P is slid and conveyed so as to include a horizontal reference guide (not shown) and a pair of skew rollers, and press the lateral end of the recording body against the reference guide. Then, the recording body is aligned with a predetermined position. The reference guide is moved and arranged at a predetermined position depending on the size of the recording medium. The lateral registration correcting mechanism 44 is composed of a regulating member that presses both sides of the recording body for a short time and a plurality of times from both lateral directions of the recording body with respect to the conveyance direction of the recording body to align the recording body at a predetermined position. The jogger method may be used.

The recording material P is conveyed from the registration roller pair 45 toward a transfer area which is a first transfer position constituted by the first intermediate transfer belt 21 and the secondary transfer roller 46. Thereafter, the sheet is transported toward a transfer area which is a second transfer position constituted by the second intermediate transfer belt 31 and the transfer charger 47.
Note that the recording medium can be supplied to the recording medium conveyance path 43C having the conveyance roller pair 42C from another sheet feeding device 300 that can be installed upstream in the conveyance direction. The upper sheet feeding surface of the sheet feeding tray 40a is arranged so that the uppermost recording medium of the sheet feeding tray 40a is fed and then conveyed substantially horizontally without being bent. Therefore, even thick recording media and highly rigid paperboard can be reliably fed. In addition, it is convenient to adopt an air sheet feeding composed of a vacuum mechanism so that the sheet feeding tray 40a can reliably feed a sheet of paper having various characteristics. Although not shown, a sensor for detecting the recording medium is provided at a key point of the recording medium conveyance path, and serves as a trigger for various signals based on the presence of the recording medium.

A recording body for transporting the recording body that has passed the second transfer position on the extension of the recording body transporting path 43A to the fixing nip of the fixing device 60 provided downstream in the transporting direction of the recording body while maintaining a planar state. A transport device 50 is provided. The recording material transport device 50 includes rollers 52, 53, 54, 55, and 56 that support a transport belt 51 that moves endlessly in the direction of the arrow. Further, on the outer side of the conveyor belt 51, a cleaning device 50A and a charge applying unit 57 for adsorbing the recording material P are provided so as to face the roller 55.
The conveyance belt 51 that moves together with the recording medium P while being in contact with the unfixed toner image is negatively charged with the same polarity as the polarity of the toner by applying a current of −200 [μA] to the charge applying unit 57. The As the transport belt 51, a metal belt, a polyimide belt, a polyamide belt, or the like can be used. A medium resistance polyimide belt having a volume resistance of 10 ⁸ to 10 ¹⁰ [Ω · cm] is preferable. The surface is provided with releasability from the toner and has a chargeable resistance value. The traveling speed of the belt 51 is matched with the traveling speed of the recording medium in the fixing device.

  A fixing device 60 having a heating unit is provided on the downstream side in the recording material conveyance direction of the recording material conveyance device 50. A type having a heater inside the roller, a belt fixing device that runs a heated belt, a fixing device that employs induction heating as a heating method, and the like can be employed. In order to make the color tone and glossiness of the images on both sides of the recording medium the same, the material, hardness, surface properties, etc. of the fixing roller and fixing belt are made equal in the vertical direction. Further, the fixing condition is controlled by a full-color and monochrome image, or single-sided or double-sided, or is controlled by a control unit (not shown) so as to obtain an optimal fixing condition according to the type of the recording medium. A cooling roller pair 70 having a cooling function is provided in the conveyance path after fixing in order to cool the recording medium after fixing and stabilize the unstable toner state at an early stage. As the cooling roller pair 70, a heat pipe structure roller having a heat radiating portion can be adopted. The cooled recording medium is discharged and stacked by a discharge roller pair 71 on a discharge stack portion 75 provided on the left side of the printer main body 100. The discharge stacking unit employs a mechanism in which a receiving member moves up and down according to a stack level by an elevator mechanism (not shown) so that a large number of recording bodies can be stacked. Note that the recording medium can also be transported to another post-processing apparatus through the paper discharge stack unit 75. As another post-processing apparatus, an apparatus for bookbinding such as drilling, cutting, folding, and binding can be connected.

The operation and display unit 90 provided on the upper surface of the printer main body 100 is provided with a keyboard and the like. As a result, conditions for image formation can be input, the status of the apparatus is displayed on the display unit, and information exchange between the operator and the printer main body 100 is facilitated.
Further, various power supplies, control boards, and the like are protected and housed in a sheet metal frame in the electrical / control device 95 provided in the printer main body 100.
In FIG. 1, reference numeral 200 denotes a document reading device, and 300 denotes a paper feeding device that can be additionally installed.

Next, an operation at the time of single-sided recording in which the printer main body 100 forms a full-color image on one side of the recording medium P will be described.
There are basically two types of single-sided recording methods that can be selected. One of the two types is a method in which an image carried on the first intermediate transfer belt 21 is directly transferred to one side of the recording medium, and the other method is an image carried on the second intermediate transfer belt 31. This is a method of transferring directly to one side of a recording medium. Here, when the image carried on the first intermediate transfer belt 21 is directly transferred to one surface of the recording medium from the configuration of the printer main body 100, the image is formed on the upper surface of the recording medium. On the other hand, when the image carried on the second intermediate transfer belt 31 is directly transferred to one side of the recording body, the image is formed on the lower surface of the recording body. In the case where the data to be recorded is a plurality of pages, it is convenient to control the image forming order so that the pages are aligned on the paper discharge stack unit 75. A method will be described in which an image is carried on the first intermediate transfer belt 21 and then transferred to a recording body so that the pages are arranged in order from the image data of the last page.

When the printer main body 100 is operated, the photoreceptors 1Y, 1C, 1M, and 1K in the first intermediate transfer belt 21 and the first image forming units 80Y to 80K are rotated. At the same time, the second intermediate transfer belt 31 rotates, but the photoreceptors 1Y, 1C, 1M, and 1K in the second image forming units 81Y to 81K are separated from the second intermediate transfer belt 31 and are not rotated. First, image formation by the image forming unit 80Y is started. By the operation of the exposure device 4 composed of an LED (light emitting diode) array and an imaging element, light corresponding to image data for yellow emitted from the LED is irradiated onto the surface of the photoreceptor 1Y uniformly charged by the charging device 3. Thus, an electrostatic latent image is formed.
This electrostatic latent image is developed with yellow toner by the developing roller 5a to become a toner image electrostatically on the first intermediate transfer belt 21 that moves in synchronization with the photoreceptor 1Y by the transfer action of the primary transfer roller 22. Primary transfer is performed. Such latent image formation, development, and primary transfer operations are sequentially performed in the same manner on the photosensitive members 1C, 1M, and 1K.
Thereafter, yellow, cyan, magenta, and black toner images are carried on the first intermediate transfer belt 21 as sequentially overlapping full-color toner images and are moved in the direction of the arrow together with the first intermediate transfer belt 21. .

  At the same time, the recording material P used for recording is fed out from the paper feed tray 40a or the paper feed cassettes 40b to 40d in the paper feed device 40 by one of the paper feed / separation means 41A to 41D for the supply. And it is conveyed by the conveyance roller pair 42B and 42C to the recording medium conveyance path 43C. Before the leading edge of the recording body is held by the registration roller pair 45, the lateral registration correction mechanism 44 operates to push both sides of the recording body from both lateral directions with respect to the conveyance direction of the recording body. Can be aligned. The registration roller pair 45 is stationary, and the leading end of the recording body is stationary while entering the nip of the registration roller pair 45. Then, the registration roller pair 45 rotates at a timing so that the position of the image on the first intermediate transfer belt 21 is normal, and the recording medium is conveyed to the transfer area.

  The full color toner image on the first intermediate transfer belt 21 is transferred to the upper surface of the recording material P conveyed in synchronization with the first intermediate transfer belt 21 by receiving a transfer action by the secondary transfer roller 46. A current of +50 [μA] is applied to the secondary transfer roller 46. After the transfer, the surface of the first intermediate transfer belt 21 is cleaned by the belt cleaning device 20A. Further, foreign matters such as toner remaining on the surfaces of the photoreceptors 1Y, 1C, 1M, and 1K in the first image forming units 80Y to 80K that have finished the primary transfer are removed by the cleaning brush 2a and the cleaning blade 2b of the cleaning device 2. Made. The surface of each photoconductor is neutralized by a residual potential by the static eliminator Q to prepare for the next image formation / transfer process. The removed foreign matter such as toner is sent to the collecting unit 87 by the collecting unit 2c. Sensors S1 and S2 detect whether the surface potential after exposure on the surface of the photoconductor and the concentration of toner attached to the surface of the photoconductor after the development process are appropriate, and appropriately set image forming conditions. Information is sent to a control means (not shown) for control.

The recording material P onto which the toner image that has been superposed and carried on the first intermediate transfer belt 21 is transferred is transferred toward the fixing device 60 by the conveyance belt 51 of the recording material conveyance device 50. In order to ensure that the recording material P can be transported together with the transport belt 51, the surface of the transport belt 51 is charged in advance to the negative polarity of the same polarity as the toner by the charge applying means 57. The recording material P is charged with a positive polarity by the secondary transfer roller 46. For this reason, the recording material conveyed to the conveyance belt 51 is conveyed in close contact with the conveyance belt 51 in an electrostatic manner. Then, the recording material P is separated from the conveyance belt 51 and sent to the fixing device 60.
The toners of the respective colors superimposed on the recording medium P are subjected to a fixing action by the heat of the fixing device 60, and are melted and mixed to form a completely color image. Since the toner is provided on only one side (upper surface) of the recording medium, less heat energy is required for fixing compared to double-sided recording having toner on both sides. A control means (not shown) optimally controls the power used by the fixing device according to the image. Until the fixed toner is completely fixed on the recording medium, it is rubbed against a guide member or the like on the conveyance path, and an image is lost or distorted. In order to prevent this problem, the cooling roller pair 70 which is a cooling unit is operated to cool the toner and the recording medium. Thereafter, the paper is discharged by the paper discharge roller 71 onto the paper discharge stack 75 with the image surface facing upward. In the paper discharge stack section 75, the image forming order is programmed so that the recorded matter of the young pages is stacked so as to be sequentially stacked on top, so the page order is aligned. Since the paper discharge stack unit 75 descends as the number of discharged recording media increases, the recording media can be stacked in an orderly and reliable manner, and the page order is not disturbed. Instead of directly stacking the recorded recording body on the paper discharge stack section 75, it is possible to carry out a punching process or transport it to a post-processing device such as a sorter, a collator, a binding device or a folding device.

  In another method of forming an image on one side of the recording medium P, image formation is not performed in the first image forming units 80Y to 80K, and image formation is performed in order from image data of young pages for page alignment. The difference is that However, since it is basically the same as the single-sided recording process described above, details are omitted.

Next, the operation during double-sided recording in which images are formed on both sides of the recording medium P will be described. When a start signal is input to the printer main body, images for each color sequentially formed by the first image forming units 80Y, 80C, 80M, and 80K described in the single-sided recording operation are sequentially applied to the first intermediate transfer belt 21 in order. Transfer. Substantially in parallel with the step of supporting the first image, the images for the respective colors sequentially formed by the second image forming units 81Y, 81C, 81M, 81K are sequentially primary-transferred to the second intermediate transfer belt 31, and the second The process of carrying as an image is performed. As shown in FIG. 1, the interval between the second image forming units in the belt conveyance direction is set closer than the interval between the first image forming units. Thereby, in order for the first image and the second image to coincide with each other at the front end in the transport direction of the recording medium, the formation of the second image is started after the start of the formation of the first image. . Further, since the recording medium is stopped and retransmitted by the registration roller pair 45, the sheet is fed in consideration of the time, and is aligned by the lateral registration correction mechanism 44. The registration roller pair 45 transports the recording medium to a first transfer station, which is a first transfer position constituted by the transfer roller 46 as the first secondary transfer means and the first intermediate transfer belt 21 at a timing. A transfer current of +50 [μA] is supplied to the transfer roller 46, and an image is transferred from the first intermediate transfer belt to one side (upper surface in the drawing) of the recording medium P.
In this way, the recording material P having an image on one side is continuously sent to the second transfer station, which is the second transfer position where the transfer charger 47 as the second secondary transfer means is located, by the conveying action of the transfer roller 46. . Then, by supplying a transfer current of +200 [μA] to the charger, the full-color second image previously carried on the second intermediate transfer belt 31 is transferred to the lower surface of the recording medium P at a time.

The recording material P on which the full color toner images are transferred on both sides receives the charge in the above transfer process, is charged with a positive polarity, and is transported to the transport belt 51. By supplying a current of −200 [μA] to the charge applying unit 57, the surface of the transport belt 51 is charged with the same negative polarity as the polarity of the toner. Since the recording medium is charged with a positive polarity, the recording medium is electrostatically brought into close contact with the conveying belt and transferred to the fixing device. On the other hand, the toner that forms the second image between the recording medium and the conveyance belt is charged with a negative polarity, and therefore does not adhere to the conveyance belt charged with the same negative polarity as the polarity of the toner. Then, the recording medium is separated from the conveyance belt 51 and transferred to the fixing mount 60. The toner image on both sides of the recording medium is melted and mixed in response to a fixing process by heat of the fixing device 60. The recording body subsequently passes through the cooling roller pair and is discharged onto the discharge stack portion 75 by the discharge roller 71.
When double-sided recording is performed on a recording medium of a plurality of pages, the image forming order is controlled so that an image of a young page becomes the bottom surface and is stacked on the paper discharge stack unit 75. When the image formation is completed, it is taken out from the stack, and when the top and bottom surfaces are reversed, the recorded matter is one page in order from the top, the second page on the back, the third page on the second sheet, and the fourth page on the back. Such control of image forming sequence and control such as increasing the power input to the fixing device compared to the one-side recording are executed by a control means (not shown).

  As for the single-sided recording and the double-sided recording operation, an example in which full-color recording is executed has been described, but monochrome recording using only black toner is also possible. When the need for maintenance or replacement of parts arises, maintenance is performed by opening an unillustrated exterior cover or the like. At this time, it is convenient to unitize the members constituting the image forming units 80 and 81 shown in FIGS. 3 and 4 and replace them as process cartridges. The configuration of the process cartridge is such that the image forming members excluding the intermediate transfer belts 21 and 31 and the primary transfer roller 22 and the exposure device 4 from the configuration shown in FIGS. It is housed and configured. Further, it can be realized by appropriately providing a guide part and a handle for attaching and detaching to the printer main body 100.

  Next, the characteristic part of this embodiment is demonstrated. When the recording medium P moves away from the second intermediate transfer belt 31 and moves to the conveying belt 51, there is a problem that toner that adheres electrostatically to the lower surface of the recording medium P is scattered. This is because the recording medium P is charged with a positive polarity by being charged by the transfer roller 46 and the transfer charger 47, and therefore when the recording medium P leaves the second intermediate transfer belt 31, the recording medium and the second intermediate transfer belt 31 The potential difference between the two increases, and peeling discharge occurs. It is considered that the toner adhering electrostatically to the lower surface of the recording medium was scattered by the impact of the peeling discharge. As described above, as a result of the toner adhering to the lower surface of the recording medium P being scattered, there is a problem that the periphery of the delivery area where the recording medium P is transferred from the second intermediate transfer belt 31 to the conveying belt 51 is stained with toner. Further, the scattered toner adheres to the charge applying means 57 disposed below the delivery area, and the performance of the charge applying means 57 is deteriorated so that the charging of the conveying belt 51 cannot be performed well. There was a possibility that conveyance failure due to uneven charging of 51 occurred.

  Therefore, in the present embodiment, as shown in FIG. 5, a toner suction device 110 that sucks the scattered toner below the delivery area D is provided. The toner suction device 110 includes an exhaust duct 111 connected to an exhaust fan (not shown) and a suction filter 112 that collects scattered toner. Due to the rotation of the exhaust fan, an air flow that sucks the air around the delivery area D to the suction filter 112 is generated, and the toner scattered by the peeling discharge by the air flow can be collected by the suction filter 112. The suction filter 112 is provided so as to be detachable from the suction device 110, and can be replaced by a service person at the time of periodic inspection. For this reason, the suction filter 112 is arranged so that it can be easily replaced when a cover (not shown) of the apparatus main body is opened. In addition, the suction filter 112 is preferably provided below the delivery area D so as to face the lower surface of the recording medium. This is because toner that adheres to the lower surface of the recording medium is scattered by the peeling discharge. Therefore, the scattered toner can be efficiently collected by providing the suction filter 112 so as to face the lower surface of the recording medium.

  For example, an image having a large image area, such as a photographic image, increases the amount of toner adhering to the recording body, and thus the amount of scattered toner increases. In addition, a recording medium having a large resistance value such as thick paper is difficult to be charged, so that the electrostatic adhesion force of the toner to the recording medium is weak and the amount of scattered toner increases. Therefore, the suction force for sucking the air around the delivery area D to the suction filter 112 may be changed by changing the number of rotations of the exhaust fan depending on the type of image and the type of paper.

  As a method of changing the rotation speed of the exhaust fan depending on the type of image, for example, there is a method of calculating the area ratio of the image from image information to be printed and changing the rotation speed of the exhaust fan based on the area ratio of the image. . The area ratio of the image can be calculated by accumulating the number of pixels of the toner adhesion planned portion to which the toner adheres among the pixels formed on the photoreceptor obtained from the exposure device 4 and the like. When the area ratio of the image calculated in this way is equal to or greater than a preset reference value, the suction force for sucking the air around the delivery area D to the suction filter 112 is changed by changing the rotation speed of the exhaust fan. increase. Further, the rotational speed of the exhaust fan is recorded in advance as a table in the recording unit of the image forming apparatus in association with the area ratio of the image. Then, the area ratio of the image calculated based on the image data obtained from the exposure device 4 and the like is compared with the area ratio of the image recorded in the recording unit, and the rotation speed of the corresponding exhaust fan is read from the table. . The rotational speed of the exhaust fan is changed based on the read rotational speed of the exhaust fan.

Not limited to this, a plurality of image forming modes are prepared in advance in the image forming apparatus, and from this image forming mode, the area ratio of the image to be formed is determined to change the rotational speed of the exhaust fan. May be. These image forming modes include character mode, photo mode, graphic mode, draft mode, etc., which can be selected from an operation unit (not shown) of the image forming apparatus or printer driver software on a personal computer. .
The image forming apparatus changes image processing parameters, image forming process conditions, and the like according to the selected image forming mode. Since these image forming modes are in accordance with the image to be printed, an approximate image area ratio can be predicted from these image forming modes. That is, if the character mode is selected, it can be predicted that the main image is printed with characters having a small image area ratio. If the photo mode is selected, it can be expected that a photo image with a high image area ratio will be printed.
The rotational speed of the exhaust fan is recorded in the recording unit of the image forming apparatus in association with these image forming modes, and when the image forming mode is changed, together with the image processing parameters and the image forming process conditions, the exhaust fan The suction force for sucking the air around the delivery region D to the suction filter 112 is changed by changing the rotation speed.

  In this way, by changing the rotation speed of the exhaust fan depending on the type of image, even if an image with a large image area is formed on the lower surface of the recording medium and the amount of toner scattered increases, the scattered toner is removed by a suction filter. It can be recovered.

  As a method of changing the rotational speed of the exhaust fan depending on the type of the recording medium, for example, a paper thickness detection means is provided upstream of the delivery area D in the recording medium conveyance direction, and based on the detection result of the paper thickness detection means, There is a method to change the rotation speed of the exhaust fan. A transmissive sensor can be used as the paper thickness detecting means. For example, a transmissive sensor is arranged in the recording paper conveyance path 43A upstream of the delivery area D in the recording material conveyance direction. As the paper thickness of the recording paper increases, the light transmitted through the recording paper decreases, so the output voltage of the light receiving element decreases according to the paper thickness of the recording paper. The relationship between the paper thickness and the output voltage is stored in advance, and the paper thickness of the recording paper is detected based on the output voltage of the transmission type sensor. Based on this detection result, the rotational speed of the exhaust fan is changed.

  A thick recording medium has a high resistance value and is difficult to be charged. Therefore, the electrostatic adhesion force of the toner to the recording medium is weak, and the toner is easily scattered by peeling discharge. Therefore, when the transmissive sensor detects a thick recording medium, the rotational speed of the exhaust fan is increased to increase the suction force of the suction filter. Thereby, even if a large amount of toner is scattered by the peeling discharge, it can be collected by the suction filter.

  On the other hand, since a thin recording medium has a low resistance value and is easily charged, the electrostatic adhesion of toner to the recording medium is strong. For this reason, even if the peeling discharge occurs, the toner is hardly scattered. However, since the thin recording body is weak, there is a possibility that a paper jam or the like may occur due to suction by the suction force of the suction device. Therefore, when the transmissive sensor detects a thin recording medium, the number of rotations of the exhaust fan is reduced to reduce the suction force of the suction device. Accordingly, the sheet can be prevented from being sucked by the suction device in the delivery area D, and the sheet jam can be suppressed. In addition, since the thin recording medium has less toner scattering due to peeling discharge, the scattered toner can be sufficiently collected in the suction filter without lowering the rotation speed of the exhaust fan and increasing the suction force of the suction filter. it can.

  In the above, the paper thickness is detected by using the transmission type sensor. However, the user specifies the paper thickness with the operation unit of the copying machine and the number of rotations of the fan based on the specification result. May be changed.

  Further, in single-sided printing in which an image is formed only on the upper surface of the recording medium, toner scattering due to peeling discharge does not occur, so the exhaust fan may be stopped and suction may be turned off.

  Further, the leading edge of the recording body is bent downward in the figure by the suction force of the toner suction device, and the leading edge of the recording body is not carried on the conveyance belt and may come into contact with the support roller, thereby causing a paper jam. . Therefore, as shown in FIG. 6, when the leading end of the recording medium passes through the delivery area D, the rotational speed of the exhaust fan may be decreased to reduce the suction force of the toner suction device. In this case, for example, as shown in FIG. 5, a paper detection sensor 120 is provided on the front side of the transfer area D in the recording medium conveyance direction, and when the paper detection sensor 120 detects the leading edge of the paper, the paper is exhausted for a predetermined time. Reduce the fan speed. As the paper detection sensor 120, a reflection type sensor is used, and the intermediate transfer belt is made of a member having a low reflectance such as black. When the recording medium passes through the paper detection sensor, the amount of reflected light changes, so that the output value of the reflective sensor changes. By detecting the change in the output value, it can be detected that the leading edge of the recording medium has passed the paper detection sensor 120. When the paper detection sensor 120 detects the leading edge of the recording medium, the rotational speed of the exhaust fan is reduced to reduce the suction force of the toner suction device. Thus, when the leading end of the recording body passes through the delivery area D, the leading end of the recording body does not move downward in the figure by the suction force of the toner suction device. As a result, it is possible to prevent the leading end of the recording body from abutting against the support roller 52 and becoming a paper jam. When the leading end of the recording medium is electrostatically attached to the conveying belt 51 after a predetermined time has elapsed, the exhaust fan is rotated again to increase the suction force of the toner suction device. Thus, the toner scattered by the peeling discharge can be collected by the suction filter by increasing the rotation speed of the exhaust fan.

  Further, when an image having a large image area is formed as described above, or as a result of increasing the suction force of the toner suction device when transporting a thick recording member, the recording member is improved by the suction force of the toner suction device. There is a risk that it will not be transported. Therefore, the current flowing through the charge applying unit 57 may be changed based on the suction force of the toner suction device. Specifically, when the suction force of the toner suction device is increased, the current flowing through the charge applying unit 57 is increased to increase the charge amount of the transport belt 51. As a result, the leading end of the recording body can be more strongly and electrostatically attached to the conveyance belt. As a result, even if the suction force of the toner suction device is increased, the recording medium is carried on the transport belt and can be transported satisfactorily to the fixing device.

  In this embodiment, the toner suction device is provided in the region D where the recording medium is transferred from the second intermediate transfer belt to the conveyance belt, but the present invention is not limited to this. For example, the toner suction device may be provided in a region where the recording medium is transferred from the conveyance belt to the fixing device. Even in this case, when the recording medium is separated from the conveyance belt, the toner on the lower surface of the recording medium which is scattered due to the occurrence of peeling discharge is sucked by the suction device, so that the fixing device is prevented from being contaminated with the scattered toner. can do. As a result, the fixing device becomes dirty, and fixing defects and the like can be suppressed. Further, the toner suction device may be provided in each of an area D where the recording medium is transferred from the second intermediate transfer belt to the conveying belt and an area where the recording medium is transferred from the conveying belt to the fixing apparatus. Thus, by providing the toner suction device in each delivery area, it is possible to suppress both fixing failure and conveyance failure of the recording medium.

In this embodiment, the recording medium is provided with a conveying belt that receives the recording medium from the second intermediate transfer belt and conveys the recording medium to the fixing device. However, the present invention is not limited to this. You may make it convey. In this case, the toner suction device is provided in a region where the recording medium is transferred from the second intermediate transfer belt to the fixing device.

(1)
As described above, according to the image forming apparatus of the present embodiment, the toner scattered by the toner suction device can be prevented from being contaminated by the scattered toner. In addition, a toner suction device is provided in a transfer area where the recording medium is transferred from the second intermediate transfer belt as a member carrying the recording body to a conveying belt as another member. As a result, the toner scattered by the peeling discharge generated when the recording material is separated from the second intermediate transfer belt can be efficiently sucked. Thereby, it is possible to suppress the periphery of the delivery area of the apparatus from being contaminated by the scattered toner.
Further, when the charge applying means for applying the charge to the conveying belt is below the delivery area, the scattered toner is suppressed from adhering to the charge applying means. As a result, it is possible to suppress the charge imparting ability from being deteriorated due to adhesion to the toner, and it is possible to suppress charging defects such as uneven charging on the transport belt. As a result, it is possible to suppress a decrease in the conveyance capability of the recording medium of the conveyance belt, and it is possible to suppress a conveyance failure of the recording medium.
(2)
Further, according to the image forming apparatus of the present embodiment, the toner suction device is provided so as to face the surface of the recording medium on the second intermediate transfer belt side. The toner that scatters around the delivery area D is the toner that adheres to the surface of the recording medium on the second intermediate transfer belt side due to detachment discharge. Therefore, by providing the toner suction device so as to face the surface of the recording medium on the second intermediate transfer belt side, the toner scattered around the delivery area D can be efficiently sucked by the toner suction device.
(3)
Further, according to the image forming apparatus of the present embodiment, since the suction force of the toner suction device is made variable, the thickness of the recording body, the image area ratio formed on the surface of the recording body on the second intermediate transfer belt side, and the like. However, even if various conditions change, the toner can be sucked with an optimum suction force.
(4)
Further, according to the image forming apparatus of the present embodiment, the suction force of the toner suction device is based on at least one of the type of the recording body and the area ratio of the image formed on the surface of the recording body on the second intermediate transfer belt side. It has changed. A thick recording paper has a high resistance value, so that it is not charged with a positive polarity even if charge is injected during secondary transfer. For this reason, the electrostatic adhesive force between the recording paper and the toner is weak, and a lot of toner is scattered by the impact of the peeling discharge. For this reason, when the type of the recording paper is a thick recording paper, the scattered toner adheres to the periphery of the delivery area if a large amount of toner is sucked by increasing the suction force of the toner suction device. This can be suppressed. In addition, since a thin recording paper has a low resistance value and is easily charged, it is sufficiently charged with a positive polarity by charge injection during secondary transfer. For this reason, the toner adheres strongly and electrostatically to the recording medium, and the toner does not scatter much even if a peeling discharge occurs. However, since the recording paper with a small thickness is weak, the recording paper may be sucked by the suction force of the toner suction device and may cause a paper jam. Therefore, when the type of the recording body is a thin recording body, the suction force of the toner suction device is lowered so that the recording body is not sucked by the suction force. As described above, in the case of a recording paper with a small thickness, toner scattering is small, so that even if the suction force of the toner suction device is reduced, the scattered toner can be sucked without any problem. Further, by reducing the suction force, the recording paper is not sucked by the toner suction device, and paper jam can be suppressed.
In this way, by changing the suction force of the toner suction device depending on the type of paper, the recording medium can be transported satisfactorily and the scattered toner can be prevented from adhering to the periphery of the delivery area. .
Also, if the area ratio of the image formed on the surface of the recording medium on the second intermediate transfer belt side is high, the amount of toner adhering to the surface of the second intermediate transfer belt side increases, and a lot of toner is removed by the peeling discharge. Scatter. Therefore, when the area ratio of the image formed on the surface of the recording medium on the second intermediate transfer belt side is high, the suction force of the toner suction device is increased so that a large amount of toner can be sucked. Thereby, even if a lot of toner is scattered, it is possible to suppress the scattered toner from adhering to the periphery of the delivery area.
As described above, the scattered toner adheres to the periphery of the delivery area by changing the suction force of the toner suction device based on the area ratio of the image formed on the surface of the recording medium on the second intermediate transfer belt side. Can be suppressed.
(5)
Further, according to the image forming apparatus of the present embodiment, the operation of the toner suction device is stopped when an image is not formed on the surface of the recording medium on the second intermediate transfer belt side. When an image is not formed on the surface of the recording medium on the second intermediate transfer belt side, no toner is scattered even if a peeling discharge occurs. Therefore, even if the operation of the toner suction device is stopped, toner is not present around the delivery area. There is no adhesion. Therefore, when an image is not formed on the surface of the recording medium on the second intermediate transfer belt side, the power consumption of the image forming apparatus can be suppressed by stopping the operation of the toner suction device.
(6)
Further, according to the image forming apparatus of the present embodiment, the suction force of the toner suction device is weakened while the leading end of the recording body passes through the delivery area. When the leading edge of the recording body passes through the delivery area, the leading edge of the recording body is attracted by the toner suction device due to the suction force of the toner suction device, and the leading edge of the recording body abuts against the support roller of the conveyance belt, thereby causing a paper jam. There is a fear. Therefore, the suction force of the toner suction device is weakened while the leading edge of the recording body passes through the delivery area. Accordingly, the leading end of the recording body is suppressed from being sucked by the toner suction device when the leading end of the recording body passes through the delivery area. Therefore, it can suppress that the front-end | tip of a recording body strikes the support roller of a conveyance belt, and can suppress paper jam.
(7)
Further, according to the image forming apparatus of the present embodiment, the amount of charge applied to the transport belt is changed based on the suction force of the toner suction device. The higher the suction force of the toner suction device, the stronger the force for sucking the recording body, and there is a possibility that the recording body cannot be transported satisfactorily. However, the amount of charge applied to the conveyor belt is changed when the suction force of the toner suction device is high. Specifically, the amount of charge applied to the conveyance belt is increased, and the electrostatic adhesion force of the recording medium to the conveyance belt is made stronger than the suction force of the toner suction device. As a result, the force with which the conveying belt conveys the recording medium to the fixing device is stronger than the suction force of the toner aspirating device, and the conveying force can be conveyed to the fixing device without being disturbed.
(8)
Further, according to the image forming apparatus of the present embodiment, the filter of the toner suction device is configured to be detachable from the toner suction device. Therefore, it is possible to maintain the suction force capability of the toner suction device simply by replacing the filter. Further, the filter can be easily replaced, and the maintenance time can be shortened.

1 is a schematic diagram of a copying machine according to an embodiment. Explanatory drawing of angle (alpha) which two image receiving surfaces form. FIG. 3 is a detailed view when the developing unit is used as a first image unit. FIG. 3 is a detailed view when the developing unit is used as a first image unit. FIG. 4 is a diagram illustrating a structure around a transfer area where a recording medium is transferred from a second intermediate transfer belt to a conveyance belt. The figure explaining the mode of the strength of the suction force of the toner suction device. The figure which shows the principal part of the image forming apparatus of a one pass system

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 5 Developing device 20 1st image unit 21 1st intermediate transfer belt 30 2nd image carrier unit 31 2nd intermediate transfer belt 50 Recording material conveyance device 51 Conveyance belt 57 Charge application means 60 Fixing device 80 First image formation Unit 81 Second image forming unit 100 Printer main body (image forming apparatus)
110 Toner Suction Device 112 Suction Filter P Recording Material

Claims (8)

In the process of transporting the recording body, the toner image is transferred to one side of the recording body, the other toner image is transferred to the other side of the recording body, and the toner image is transferred to both sides of the recording body. In an image forming apparatus for conveying a recording body onto which a toner image has been transferred to a fixing unit and fixing the toner image on the recording body,
At least the recording of the recording body is provided in a transfer area where the recording body is transferred from a member carrying the recording body to another member while the recording body on which the toner image is transferred is conveyed to a fixing unit. An image forming apparatus comprising a toner suction device that sucks toner scattered from a surface of a member carrying a body. The image forming apparatus according to claim 1.
The image forming apparatus according to claim 1, wherein the toner suction device is provided so as to face a surface of the recording member on a side of the member carrying the recording member. The image forming apparatus according to claim 1 or 2,
An image forming apparatus, wherein the suction force of the toner suction device is variable. The image forming apparatus according to claim 3.
The suction force of the toner suction device is changed based on at least one of the type of the recording body and the area ratio of an image formed on the member-side surface of the recording body. Image forming apparatus. The image forming apparatus according to claim 3 or 4,
An image forming apparatus characterized in that the operation of the toner suction device is stopped when an image is not formed on the surface of the recording member on the side of the member carrying the recording member. The image forming apparatus according to any one of claims 3 to 5,
The suction force of the toner suction device while the leading edge of the recording body passes through the delivery area, until the trailing edge of the recording body has passed through the delivery area after the leading edge of the recording body has passed the delivery area. An image forming apparatus characterized in that the suction force is weaker than that between the two. The image forming apparatus according to any one of claims 3 to 6,
A transport member that transports the recording body onto which the toner image has been transferred by applying a charge having a reverse polarity to the charge on the recording paper to the fixing unit;
An image forming apparatus, wherein the amount of charge applied to the conveying member is changed based on the suction force of the toner suction device. The image forming apparatus according to claim 1,
The toner suction device includes a filter for collecting toner, and the filter is configured to be detachable from the toner suction device.

Images