JP2005195650A - Transfer device - Google Patents

Abstract

A front end portion of a first recording material is landed on a more downstream side in a discharging direction on an upper surface of a storage portion to prevent the recording material from being bent or discharged.
A detection signal of a paper discharge sensor 32 that detects a passing state of a recording material in a paper discharge roller 34, a detection signal of a storage sensor 33 that detects the presence or absence of a recording material on a paper discharge tray 31, and an image forming apparatus A control unit 40 is provided for controlling the rotation speed of the paper discharge motor 35 that supplies rotation to the paper discharge roller 34 based on data input from the main control unit 110. When the first recording material discharged to the paper discharge tray 31 is an OHP sheet, the control unit 40 determines the rotation speed of the paper discharge motor 35 after the rear end of the OHP sheet passes through the fixing unit 7. Change from v1 corresponding to the forming process speed to a higher speed v2.
[Selection] Figure 2

Description

  The present invention relates to a recording material discharging apparatus for discharging a recording material on which an image has been formed by an electrophotographic image forming process to a storage portion.

  In an image forming apparatus that performs electrophotographic image forming processing, a recording material that has received a transfer of a toner image in a transfer unit is heated and pressed in a fixing unit to melt and fix the toner image. Thereafter, the recording material is discharged to a storage unit such as a paper discharge tray by a discharge unit.

  In such an image forming apparatus, an image may be formed not only on plain paper as a recording material but also on an overhead projector sheet (hereinafter referred to as an OHP sheet) made of a transparent resin film. When forming an image on an OHP sheet, it is necessary to apply a higher amount of heat in the fixing unit than when forming an image on plain paper. This is because the layer thickness of the toner image on the OHP sheet must be sufficiently thin so that the illumination light can pass through the toner image when the OHP sheet is used, and the illumination light is not diffusely reflected. This is because the surface of the image must be smooth.

For this reason, in the conventional image forming apparatus, the control temperature in the fixing unit is increased during image formation on the OHP sheet (see, for example, Patent Documents 1 and 2), or the conveyance speed when passing through the fixing unit is set. Some have been made to be slow (see, for example, Patent Document 3).
Japanese Patent Application Laid-Open No. 02-0665887 Japanese Patent Laid-Open No. 04-067172 Japanese Patent Laid-Open No. 06-208262

  However, since the OHP sheet is made of a thermoplastic transparent resin film, the OHP sheet is softened and reduced in elasticity when heated at the fixing portion. In recent years, due to a demand for space saving, an image forming apparatus has been provided with a paper discharge unit in the vicinity of the fixing unit, and the OHP sheet heated by the fixing unit has not been sufficiently lowered in temperature in the storage unit. Discharged. In the image forming apparatus, in order to store a predetermined amount of recording material in the storage unit, a recording material discharge port is provided at a position spaced upward from the upper surface of the storage unit.

  For this reason, the OHP sheet discharged from the discharge port to the storage portion is pushed out from the discharge port after the front end collides with the front side in the discharge direction on the upper surface of the storage portion, and the intermediate portion is bent and curved. It is accommodated in the accommodating part. If the OHP sheet is cooled and solidified in a curved shape in the accommodating portion in this state, the OHP sheet cannot be used properly.

  Usually, the upper surface of the storage portion is inclined so that the front side in the discharge direction is lower so that the positions of a plurality of recording materials can be aligned and stored. If the inclination of the upper surface of the storage unit is strong, the leading end of the OHP sheet does not move in the discharge direction after colliding with the upper surface of the storage unit, and not only does the OHP sheet stored in the storage unit have a large curve, but also the OHP sheet is inverted. The rear end of the OHP sheet becomes clogged with the discharge port, and the OHP sheet cannot be discharged properly. This phenomenon is considered to be due to the fact that the frictional resistance between the leading edge of the OHP sheet and the upper surface of the housing portion increases, and that static electricity remains on the OHP sheet immediately after the end of image formation.

  However, as long as at least one recording material is accommodated on the accommodating portion, the OHP sheet that is subsequently discharged is accommodated smoothly, and the OHP sheet is not bent or discharged poorly.

  The present invention has been made by paying attention to the fact that if at least one recording material is accommodated on the accommodating portion, the recording material discharged thereafter is smoothly accommodated in the accommodating portion. It is an object of the present invention to provide a recording material discharging apparatus that can prevent the recording material from curving or discharging poorly so that the front end portion of the recording material is landed more downstream in the discharging direction on the upper surface of the accommodating portion.

  The present invention has the following configuration as means for solving the above-described problems.

(1) A discharge unit that is provided in an image forming apparatus that forms an image on a recording material by electrophotographic image forming processing and discharges the recording material that has been heated in the fixing unit to a predetermined storage unit; Control means for controlling the discharge speed of the recording material by,
The control means is a high-speed controller that sets the discharge speed of the first recording material in each of the image forming jobs constituted by the image forming process for at least one recording material to be higher than the discharge speed of the second and subsequent recording materials. It is characterized by performing discharge control.

  In this configuration, the first recording material is discharged into the storage portion at a higher discharging speed than the second and subsequent recording materials. Therefore, the front end portion of the first recording material lands on the front side in the discharge direction on the upper surface of the storage portion rather than the front end portions of the second and subsequent recording materials.

(2) The control means performs the high-speed discharge control when discharging a specific type of recording material.

  In this configuration, during the image forming process for a specific type of recording material, the first recording material is discharged to the storage unit at a higher discharge speed than the second and subsequent recording materials. Therefore, only when the first recording material discharged to the storage portion is a specific type of recording material, the front end portion of the recording material is higher than the front end portion of the second and subsequent recording materials. Land in front of the discharge direction.

(3) The specific type of recording material is an OHP sheet.

  In this configuration, during the image forming process for the OHP sheet, the first OHP sheet is discharged to the storage unit at a higher discharge speed than the second and subsequent recording materials. Therefore, only when the first recording material discharged to the storage portion is an OHP sheet, the front end portion of the OHP sheet is more forward in the discharge direction on the upper surface of the storage portion than the front end portions of the second and subsequent recording materials. Land on.

(4) The image forming apparatus further includes a detection unit that detects the presence or absence of a recording material in the storage unit, and performs the high-speed discharge control when the detection unit has not detected the recording material.

  In this configuration, when the detection unit does not detect the recording material in the storage unit, the first recording material is discharged to the storage unit at a higher discharge speed than the second and subsequent recording materials. Therefore, only the first recording material whose front end portion is in direct contact with the upper surface of the storage portion lands ahead of the front end portion of the second and subsequent recording materials in the discharge direction on the upper surface of the storage portion.

(5) The control unit does not perform the high-speed discharge control for subsequent image forming jobs in a plurality of image forming jobs executed continuously.

  In this configuration, when a plurality of image forming jobs each consisting of an image forming process for at least one recording material are continuously performed, the first recording in the image forming job other than the first image forming job is performed. The material is discharged at the same discharge speed as the second and subsequent recording materials. Therefore, in a state where at least one recording material is already accommodated in the accommodating portion, the recording material is not discharged at a high speed.

(6) The high-speed discharge control is a control for increasing the discharge speed of the discharge unit after the trailing edge of the first recording material passes through the fixing unit.

  In this configuration, the recording material discharge speed is not increased until the trailing edge of the first recording material passes through the fixing unit. Therefore, the amount of heat given by the fixing unit does not change midway in the first recording material.

  According to the present invention, the following effects can be obtained.

(1) The front end portion of the first recording material can be landed ahead of the front end portion of the second and subsequent recording materials in the discharge direction on the upper surface of the storage portion, and has collided with the upper surface of the storage portion. It is possible to smoothly move the front end portion of the first recording material in the discharge direction along the upper surface of the storage portion. Thus, even when the recording material does not have sufficient elasticity, it is possible to prevent the recording material from being bent or discharged, and the recording material can be appropriately stored in the storage portion.

(2) The sheet is discharged at a high speed only when the first recording material discharged to the storage unit is a specific type of recording material that is liable to bend or discharge poorly. Therefore, it is possible to prevent the normal recording material from being discharged at high speed. As a result, it is possible to prevent a specific type of recording material from being bent or to be ejected properly, so that the recording material can be properly accommodated in the accommodating portion, and normal recording material is discharged in the ejection direction beyond the accommodating portion. Therefore, it is possible to prevent a housing failure in the housing portion.

(3) The sheet is discharged at a high speed only when the first recording material discharged to the storage portion is an OHP sheet that is likely to be bent or discharged, and is not likely to be bent or discharged in the storage portion of plain paper or the like. This recording material can be prevented from being discharged at a high speed. As a result, it is possible to prevent the OHP sheet from being bent or to be discharged and to properly store the OHP sheet in the storage portion, and to discharge a normal recording material beyond the storage portion in the discharge direction. It is possible to prevent housing failure in the housing portion.

(4) Only the first recording material in which the front end portion is in direct contact with the upper surface of the storage portion can be landed forward in the discharge direction on the upper surface of the storage portion rather than the front end portions of the second and subsequent recording materials, At least one recording material is already accommodated in the accommodating portion, and it is possible to prevent the recording material from being discharged at a high speed in a state where it is difficult for the recording material to be bent or discharged. Accordingly, it is possible to prevent a storage failure in the storage portion due to the recording material being discharged beyond the storage portion in the discharge direction.

(5) In a state where at least one recording material is already stored in the storage portion, it is possible to prevent the recording material from being discharged at a high speed. Accordingly, it is possible to prevent a storage failure in the storage portion due to the recording material being discharged beyond the storage portion in the discharge direction.

(6) The amount of heat applied by the fixing unit can be prevented from changing in the middle of the first recording material, and the image forming state in one recording material can be kept constant, and deterioration in image quality can be prevented. can do.

  FIG. 1 is a diagram showing a configuration of an image forming apparatus provided with a recording material discharging apparatus according to an embodiment of the present invention. The image forming apparatus 100 performs an electrophotographic image forming process including charging, exposure, development, transfer, and cleaning processes on a recording material such as paper based on image data input from the outside. For this reason, the image forming apparatus 100 includes a charger 2, an exposure unit 3, a developing unit 4, a transfer unit 5 and a cleaner 6 around the photosensitive drum 1 on which a photosensitive layer generating a photoconductive action is formed. An image forming unit 10 arranged in this order along the rotation direction of the drum 1 is provided.

  The charger 2 uniformly applies a charge having the same polarity as the charging polarity of the toner to the surface of the photosensitive drum 1. The exposure unit 3 exposes the surface of the photosensitive drum 1 with the image light modulated by the image data, removes the charge in the exposed portion, and forms an electrostatic latent image on the surface of the photosensitive drum 1. The developing unit 4 supplies toner to the surface of the photosensitive drum 1 to visualize the electrostatic latent image into a toner image. The transfer unit 5 applies a voltage having a polarity opposite to the charging polarity of the toner to the recording material sandwiched between the photosensitive drum 1 and transfers the toner image onto the surface of the recording material. The cleaner 6 removes the toner remaining on the surface of the photosensitive drum 1 after the transfer process.

  The image forming apparatus 100 is placed on the paper feeding device 200. The paper feeding device 200 is provided with paper feeding trays 201 to 204. Paper feed rollers 211 to 214 are disposed in the paper feed trays 201 to 204, respectively. A main transport path 20 is formed from each of the paper feed trays 201 to 204 via the image forming unit 10 in the image forming apparatus 100 to the discharge port 30a. The recording material stored in any of the paper feed trays 201 to 204 is fed into the main conveyance path 20 via any of the paper feed rollers 211 to 214, and then the photosensitive drum of the image forming unit 10. 1 and the transfer unit 5.

  The discharge port 30 a includes a discharge roller 34 and opens on the upper surface of the image forming apparatus 100. On the upper surface of the image forming apparatus 10, a paper discharge tray 31 which is a storage portion of the present invention is provided. The paper discharge tray 31 is provided with a storage sensor 33 which is a detection means of the present invention that detects the presence or absence of a recording material. In addition, a paper discharge sensor 32 that detects the passing state of the recording material is provided at the discharge port 30a. The paper discharge tray 31, paper discharge sensor 32, storage sensor 33, and paper discharge roller 34 together with a paper discharge motor, which will be described later, constitute a discharge unit 30 that is a discharge means of the present invention. The upper surface of the paper discharge tray 31 is inclined with the upstream side in the recording material discharge direction down. This is because a plurality of discharged recording materials are accommodated in alignment with the rear end position as a reference.

  In the main conveyance path 20, a fixing unit 7 which is a fixing unit of the present invention is disposed between the image forming unit 10 and the discharge port 30a. The fixing unit 7 includes a heating roller 7a and a pressure roller 7b, and heats and presses the recording material that has completed the transfer process to melt and fix the toner image on the surface of the recording material.

  FIG. 2 is a diagram showing a configuration of the recording material discharging apparatus. A recording material discharging apparatus 40 according to an embodiment of the present invention includes a paper discharge tray 31, a paper discharge sensor 32, a storage sensor 33, a paper discharge roller 34, and a paper discharge motor 35. The control unit 40 controls the operation of the paper discharge unit 30.

  The control unit 40 is a control unit of the present invention, and drives and controls a paper discharge motor 35 that supplies rotation to the paper discharge roller 34 based on detection signals from the paper discharge sensor 32 and the storage sensor 33. The rotational speed of the paper discharge motor 35 defines the recording material discharge speed. The control unit 40 is connected to the main control unit 110 of the image forming apparatus 100. The control unit 40 receives data from the main control unit 110 to start image forming processing, data for specifying the type of recording material to be subjected to image forming processing, and the rear end of the recording material from the fixing unit 7. Data indicating that it has passed is supplied.

  As an example, the paper discharge sensor 32 and the accommodation sensor 33 are optical sensors in which a light emitting element and a light receiving element are arranged to face each other with a predetermined gap, and are provided with actuators 32a and 33a so as to be swingable.

  The actuator 32a allows the upper end portion to enter the gap between the light emitting element and the light receiving element of the paper discharge sensor 32 while the recording material passing through the discharge port 30a contacts the lower end portion, thereby shielding the light from the light emitting element. The paper discharge sensor 32 outputs to the control unit 40 a detection signal that is turned on / off depending on whether the light receiving element receives light from the light emitting element. The control unit 40 detects whether the recording material passes through the discharge port 30a according to the state of the detection signal.

  The actuator 33a blocks the light of the light emitting element by causing the lower end portion to enter the gap between the light emitting element and the light receiving element of the accommodating sensor 33 while the recording material accommodated on the paper discharge tray 31 is in contact with the upper end portion. To do. The accommodation sensor 33 outputs a detection signal that is turned on / off according to whether or not the light receiving element receives light from the light emitting element to the control unit 40. The control unit 40 detects whether or not at least one recording material is stored on the paper discharge tray 31 according to the state of the detection signal.

  3 to 8 are views for explaining a recording material discharge state in the recording material discharge apparatus. The recording material (plain paper) P for which image forming processing has been completed in the image forming apparatus 100 desirably passes through the ideal line indicated by the broken line in FIG. The plain paper P that has been subjected to the image forming process in an environment of normal temperature and normal humidity is discharged from the discharge port 30a onto the discharge tray 31 along a substantially ideal line as shown by a solid line in FIG. The plain paper P whose rear end has passed the paper discharge roller 34 passes through the state shown in FIG. 4, and the upper end along the upper surface of the paper discharge tray 31 as shown in FIG. The paper is stored in the paper discharge tray 31 in a state of being in contact with the surface 31a.

  On the other hand, in the image forming process for the OHP sheet P ′ made of a thermoplastic transparent resin film, the OHP sheet P ′ to be discharged from the discharge port 30a onto the discharge tray 31 by the discharge roller 34 is Flexibility is increased by heating when passing through the fixing unit 7, and elastic force is decreased. For this reason, as shown in FIG. 6, the front end of the OHP sheet P ′ quickly drops downward and collides with the upper surface of the paper discharge tray 31 on the upstream side in the discharge direction from the ideal line. The front end of the OHP sheet P ′ that is in contact with the upper surface of the paper discharge tray 31 does not move smoothly downstream in the discharge direction, and as shown in FIG. It is stored on the paper discharge tray 31. As a result, the consistency of a plurality of recording materials stacked and accommodated is deteriorated, or the discharge of the subsequent recording material is affected, and the rear end of the OHP sheet P ′ having a curved middle portion is the discharge port 30a. The recording material may be damaged and a paper jam may occur in the discharge port 30a. Further, when the distance between the discharge port 30 a and the upper surface of the paper discharge tray 31 is long, the OHP sheet P ′ may be reversed on the paper discharge tray 31.

  On the other hand, as shown in FIG. 8, the front end of the OHP sheet P ′ discharged in a state in which one or more recording materials (regardless of types) P are already accommodated on the discharge tray 31 is early. Even if it falls downward, it easily moves in the paper discharge direction as shown by the arrow along the upper surface of the recording material P accommodated first, and does not bend at the middle portion, so that it does not curve on the paper discharge tray 31. It is stored properly.

  FIG. 9 is a flowchart illustrating an example of a processing procedure in the control unit. When an image formation processing start signal related to one image forming job is input from the main control unit 110 (S1), the control unit 40 starts driving the paper discharge motor 35 (S2). At this time, the paper discharge motor 35 is set to the normal rotation speed v1. The rotation speed v <b> 1 is a speed corresponding to the image forming process speed in the image forming unit 10 of the image forming apparatus 100. In other words, the rotation speed v1 is a speed that matches the discharge speed of the recording material discharged by the paper discharge roller 35 with the conveyance speed of the recording material when passing through the image forming unit 10.

  Next, it is determined whether or not data indicating that the target of the image forming process is an OHP sheet is input from the main control unit 110 (S3). If the OHP sheet is the target, based on the detection signal of the accommodation sensor 33. Then, it is determined whether or not the recording material is stored on the paper discharge tray 31 (S4).

  When the recording material is not accommodated on the paper discharge tray 31, the control unit 40 waits for the trailing edge of the OHP sheet to pass through the fixing unit 7 (S5), and the trailing edge of the OHP sheet causes the fixing unit 7 to pass. When the sheet passes, the sheet discharge motor 3 is driven at a rotational speed v2 (v2> v1) until the trailing edge of the OHP sheet passes the sheet discharge roller 34 (S6, S7). The processing of s6 and s7 is the high speed discharge control of the present invention.

  When the trailing edge of the OHP sheet passes the paper discharge roller 34, the control unit 40 drives the paper discharge motor 35 at the rotation speed v1 until the image forming job is completed (S8, S9).

  When the target of the image forming process is not an OHP sheet, or when at least one recording material is already stored on the paper discharge tray 31, the control unit 40 drives the paper discharge motor 35 at the rotational speed v1. (S3 → S8, S4 → S8).

  Through the above processing, as shown in job A shown in FIG. 10A or job B shown in FIG. 10B, the elastic force is reduced by heating in the fixing unit 7, and the front end is upstream of the discharge direction in the discharge tray 31. The discharge of the OHP sheet is performed at the time of image formation of the OHP sheet that collides with the sheet, and when the recording material is not stored in the discharge tray 31 and the front end of the OHP sheet is difficult to move downstream in the discharge direction. Speed is increased.

  As a result, the position where the front end of the OHP sheet lands (collises) on the surface of the discharge tray 35 can be moved downstream in the discharge direction, and the front end of the OHP sheet can move smoothly in the discharge direction. Are not bent or the front end of the OHP sheet stays at the discharge port 30a and does not cause a discharge failure.

  Further, since the rotation speed of the paper discharge motor 35 is changed from v1 to v2 after the trailing edge of the OHP sheet passes through the fixing unit 7, the conveyance speed does not change while the OHP sheet passes through the fixing unit 7. It is possible to prevent the toner fixing state from changing in the middle of one OHP sheet and lowering the image quality.

  As shown in FIG. 10C, even if an image forming job includes an image forming process for an OHP sheet, if the first recording material is not an OHP sheet, or as in job B shown in FIG. Even if the first recording material is an OHP sheet, the rotation speed of the paper discharge motor 35 is set to v1 when the first recording material is discharged for the subsequent image forming job executed continuously with the preceding job A. The process of changing from v2 to v2 is not performed. This is because another recording material is already accommodated on the paper discharge tray 31 when the OHP sheet is discharged.

  The accommodation sensor 33 for detecting the presence or absence of the recording material on the paper discharge tray 31 can be omitted. In this case, the first recording material in the current image forming job depends on whether or not a predetermined time has elapsed from the timing at which the preceding image forming job is completed to the start of the current image forming job. It is determined whether or not the rotational speed of the paper discharge motor 35 is changed from v1 to v2 when the (OHP sheet) is discharged.

1 is a diagram illustrating a configuration of an image forming apparatus including a recording material discharge device according to an embodiment of the present invention. It is a figure which shows the structure of the said recording material discharge apparatus. FIG. 6 is a diagram illustrating a normal discharge state of a recording material in the recording material discharge device. FIG. 6 is a diagram illustrating a normal discharge state of a recording material in the recording material discharge device. FIG. 4 is a diagram illustrating a normal storage state of a recording material in the recording material discharge device. FIG. 5 is a diagram illustrating a discharge state of a first OHP sheet in the recording material discharge apparatus. FIG. 5 is a diagram illustrating a discharge state of a first OHP sheet in the recording material discharge apparatus. FIG. 5 is a diagram illustrating a discharge state of second and subsequent OHP sheets in the recording material discharge apparatus. It is a flowchart which shows an example of the process sequence in the said control part. FIG. 4 is a diagram for explaining a relationship between the configuration of an image forming job and a control state of a paper discharge speed in the image forming apparatus.

Explanation of symbols

7 Fixing unit (fixing part)
10 Image forming section 30 Paper discharge section (discharge means)
31 Output tray (container)
32 Paper discharge roller 33 Storage sensor (detection means)
40-control unit (control means)
100 Image forming apparatus

Claims (6)

A discharge unit that is provided in an image forming apparatus that forms an image on a recording material by electrophotographic image forming processing, discharges the recording material heated in the fixing unit to a predetermined storage unit, and the recording material by the discharging unit Control means for controlling the discharge speed of
The control means is a high-speed controller that sets the discharge speed of the first recording material in each of the image forming jobs constituted by the image forming process for at least one recording material to be higher than the discharge speed of the second and subsequent recording materials. A recording material discharging apparatus that performs discharging control.   The recording material discharge apparatus according to claim 1, wherein the control unit performs the high-speed discharge control when discharging a specific type of recording material.   The recording material discharging apparatus according to claim 2, wherein the specific type of recording material is an OHP sheet.   The recording material according to claim 1, further comprising a detection unit that detects the presence or absence of the recording material in the storage unit, and performing the high-speed discharge control when the detection unit has not detected the recording material. Discharging device.   The recording material discharging apparatus according to claim 1, wherein the control unit does not perform the high-speed discharge control for subsequent image forming jobs in a plurality of image forming jobs that are continuously executed.   The recording material discharge according to claim 1, wherein the high-speed discharge control is a control for increasing a discharge speed of the discharge unit after a rear end of the first recording material passes through the fixing unit. apparatus.

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