JP2013228471A - Image forming apparatus - Google Patents

Abstract

An image forming apparatus is provided that reduces the possibility of defects occurring in an image formed on a transfer material due to the occurrence of bleeding.
An image forming apparatus includes a temperature / humidity sensor 100 for measuring temperature and humidity, a mode setting unit 131 for setting the image forming apparatus to one of an image forming mode and a power saving mode, and a mode setting unit. Whether or not cleaning is performed using the drum cleaning unit 11 based on the temperature and humidity data related to the temperature and humidity measured by the temperature and humidity sensor 100 when the power saving mode is set to the image forming mode by 131. A determination unit 132 for determining, and an execution control unit 133 for executing cleaning of the surface of the photosensitive drum 2 using the drum cleaning unit 11 when the determination unit 132 determines that cleaning is to be performed.
[Selection] Figure 2

Description

  The present invention relates to an image forming apparatus that forms an image on a transfer material.

  In image forming apparatuses such as printers, copiers, and multifunction machines, an electrostatic latent image is formed on the surface of a photosensitive drum, and then the electrostatic latent image is developed with toner to form a toner image. Is transferred to a transfer material (paper). In the image forming apparatus, when an electrostatic latent image is formed on a photosensitive drum, first, the surface of the photosensitive drum is uniformly charged by a charging roller in contact with the surface of the photosensitive drum. The charging roller includes a conductive rubber containing an ionic conductive agent on the surface.

  By the way, there is a possibility that bleeding occurs in the charging roller as the environment in which the image forming apparatus is arranged is in a high temperature and high humidity state, for example. Bleed is a phenomenon in which an ionic conductive agent appears on the surface of a conductive rubber. When such a bleed occurs, the ionic conductive agent adheres to the photosensitive drum and a defect (for example, white streaks) occurs in the image formed on the paper. In order to prevent such a problem, some image forming apparatuses have an improved charging roller (see Patent Document 1).

JP 2001-337515 A

  However, in the conventional image forming apparatus, even if the occurrence of bleeding can be prevented by improving the charging roller, other functions may be deteriorated. For example, when the amount of the ionic conductive agent contained in the rubber is reduced in order to prevent bleeding, the resistance value of the charging roller increases, and the function of charging the photosensitive drum deteriorates.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that reduces the possibility of problems occurring in an image formed on a transfer material due to the occurrence of bleeding.

  The present invention provides an electrostatic latent image on the surface of the image carrier by irradiating light on the surface of the image carrier, a charging unit for charging the surface of the image carrier, and the surface of the charged image carrier. An exposure unit to be formed and a developing unit for developing the electrostatic latent image formed by the exposure unit with toner by supplying toner to the image carrier and forming a toner image on the surface of the image carrier A transfer unit that directly or indirectly transfers a toner image formed on the surface of the image carrier to a transfer material; and a downstream side of the image carrier in the rotation direction of the image carrier, and the image A cleaning unit for cleaning the surface of the carrier, a temperature / humidity measuring unit for measuring temperature and humidity, and an image forming mode capable of transferring a toner image formed on the surface of the image carrier to a transfer material And the power consumed by the image forming device A mode setting unit that sets the image forming apparatus to any one of the power saving modes that are less than the image forming mode, and when the mode setting unit sets the image forming mode from the power saving mode, Based on temperature and humidity data related to temperature and humidity measured by the temperature / humidity measurement unit, a determination unit that determines whether or not to perform cleaning using the cleaning unit and a determination unit that determines that cleaning is performed And an execution control unit that executes cleaning of the surface of the image carrier using the cleaning unit.

  According to the present invention, it is possible to provide an image forming apparatus that reduces the possibility that a defect occurs in an image formed on a transfer material due to the occurrence of bleeding.

FIG. 4 is a diagram for explaining an arrangement of each component of the printer. FIG. 2 is a block diagram illustrating a functional configuration of a printer. It is a figure which shows an example of 1st condition data. It is a figure which shows an example of 2nd condition data. 6 is a flowchart for explaining a characteristic operation of the printer.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
With reference to FIG. 1, the overall structure of a printer 1 as an image forming apparatus according to the present embodiment will be described. FIG. 1 is a diagram for explaining the arrangement of each component of the printer 1.

As shown in FIG. 1, a printer 1 as an image forming apparatus includes an apparatus main body M and an image forming unit GK that forms a predetermined toner image on a sheet T as a sheet-like transfer material based on predetermined image information. And a paper supply / discharge unit KH that supplies the paper T to the image forming unit GK and discharges the paper T on which the toner image is formed.
The outer shape of the apparatus main body M is configured by a case body BD as a casing.

  As shown in FIG. 1, the image forming unit GK includes a photosensitive drum 2 as an image carrier (photosensitive member), a charging unit 10, a laser scanner unit 4 as an exposure unit, and a developing device 16 as a developing unit. And a toner cartridge 5, a toner supply unit 6, a drum cleaning unit 11 as a cleaning unit, a static eliminator 12, a transfer roller 8 as a transfer unit, and a fixing unit 9.

  As shown in FIG. 1, the paper supply / discharge unit KH includes a paper feed cassette 52, a manual paper feed unit 64, a transport path L of the paper T, a registration roller pair 80, and a paper discharge unit 50.

Hereinafter, each configuration of the image forming unit GK and the paper supply / discharge unit KH will be described in detail.
First, the image forming unit GK will be described.
In the image forming unit GK, in order from the upstream side to the downstream side along the surface of the photosensitive drum 2, charging by the charging unit 10, exposure by the laser scanner unit 4, development by the developing device 16, transfer by the transfer roller 8. Then, static elimination by the static eliminator 12 and cleaning by the drum cleaning unit 11 are performed.

  The photosensitive drum 2 is made of a cylindrical member and functions as a photosensitive member or an image carrier. The photosensitive drum 2 is disposed so as to be rotatable in the direction of an arrow about a rotation axis extending in a direction orthogonal to the conveyance direction of the paper T in the conveyance path L. An electrostatic latent image can be formed on the surface of the photosensitive drum 2.

  The charging unit 10 is disposed to face the surface of the photosensitive drum 2. The charging unit 10 uniformly charges the surface of the photosensitive drum 2 to be negative (minus polarity) or positive (plus polarity). Specifically, the charging unit includes a charging roller 10a (charging member) that contacts the surface of the photosensitive drum. A conductive member containing an ionic conductive agent is disposed on the surface of the charging roller 10a. The conductive member is, for example, epichlorohydrin rubber.

  The laser scanner unit 4 functions as an exposure unit, and is disposed apart from the surface of the photosensitive drum 2. The laser scanner unit 4 includes a laser light source (not shown), a polygon mirror, a polygon mirror driving motor, and the like.

  The laser scanner unit 4 forms an electrostatic latent image on the surface of the photosensitive drum 2 by irradiating light on the surface of the charged photosensitive drum 2. That is, the laser scanner unit 4 scans and exposes the surface of the photosensitive drum 2 based on image information input from an external device such as a PC (personal computer). By performing scanning exposure with the laser scanner unit 4, the charge on the exposed portion of the surface of the photosensitive drum 2 is removed. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 2.

  The developing device 16 supplies toner to the photosensitive drum 2 to develop the electrostatic latent image formed by the laser scanner unit 4 with toner, thereby forming a toner image on the surface of the photosensitive drum 2. That is, the developing device 16 is provided corresponding to the photosensitive drum 2 and is disposed to face the surface of the photosensitive drum 2. The developing device 16 attaches a single color (usually black) toner to the electrostatic latent image formed on the photoconductive drum 2 to form a single color toner image on the surface of the photoconductive drum 2. The developing device 16 includes a developing roller 17 disposed opposite to the surface of the photosensitive drum 2, a stirring roller 18 for stirring the toner, and the like.

  The toner cartridge 5 is provided corresponding to the developing device 16 and stores toner supplied to the developing device 16.

  The toner supply unit 6 is provided corresponding to the toner cartridge 5 and the developing device 16, and supplies the toner contained in the toner cartridge 5 to the developing device 16. The toner supply unit 6 and the developing device 16 are connected by a toner supply path (not shown).

  The transfer roller 8 directly or indirectly transfers the toner image formed on the surface of the photosensitive drum 2 to the paper T. In the case of this embodiment, the transfer roller 8 transfers the toner image directly from the photosensitive drum 2 to the paper T. That is, the transfer roller 8 transfers the toner image developed on the surface of the photosensitive drum 2 to the paper T. A transfer bias for transferring the toner image formed on the photosensitive drum 2 to the paper T is applied to the transfer roller 8 by a transfer bias applying unit (not shown). The transfer roller 8 is configured to be rotatable while in contact with the photosensitive drum 2.

  A sheet T conveyed through the conveyance path L is sandwiched between the photosensitive drum 2 and the transfer roller 8. The sandwiched paper T is pressed against the surface of the photosensitive drum 2. A transfer nip N is formed between the photosensitive drum 2 and the transfer roller 8. In the transfer nip N, the toner image developed on the photosensitive drum 2 is transferred onto the paper T.

  The static eliminator 12 is disposed to face the surface of the photosensitive drum 2. The static eliminator 12 irradiates the surface of the photosensitive drum 2 with light, thereby neutralizing the surface of the photosensitive drum 2 after the transfer is performed (removing the electric charge).

  The drum cleaning unit 11 is disposed downstream of the transfer roller 8 in the rotation direction of the photosensitive drum 2 and cleans the surface of the photosensitive drum 2. That is, the drum cleaning unit 11 is disposed to face the surface of the photosensitive drum 2. The drum cleaning unit 11 removes toner and deposits remaining on the surface of the photosensitive drum 2, and transports the removed toner and the like to a predetermined recovery mechanism for recovery.

  The fixing unit 9 melts and presses the toner constituting the toner image transferred to the paper T and fixes the toner on the paper T. The fixing unit 9 includes a heating rotator 9a heated by a heater and a pressure rotator 9b pressed against the heating rotator 9a. The heating rotator 9a and the pressure rotator 9b sandwich and pressurize the paper T on which the toner image has been transferred, and convey the paper T. By transporting the paper T while being sandwiched between the heating rotator 9a and the pressure rotator 9b, the toner transferred onto the paper T is melted and pressurized, and is fixed to the paper T.

Next, the paper supply / discharge unit KH will be described.
As shown in FIG. 1, in the lower part of the apparatus main body M, a single paper feed cassette 52 that stores paper T is disposed. The paper feed cassette 52 is configured to be drawable in the horizontal direction from the right side (the right side in FIG. 1) of the apparatus main body M. In the paper feed cassette 52, a placement plate 60 on which the paper T is placed is disposed. In the paper feed cassette 52, the paper T is stored in a state of being stacked on the placement plate 60. The paper T placed on the placement plate 60 is sent out to the transport path L by the cassette paper feed unit 51 arranged at the paper feed side end of the paper feed cassette 52 (the right end in FIG. 1). The cassette paper feed unit 51 includes a forward feed roller 61 for taking out the paper T on the placement plate 60 and a paper feed roller pair 63 for feeding the paper T one by one to the transport path L. Is provided.

  On the right side (right side in FIG. 1) of the apparatus main body M, a manual paper feed unit 64 is provided. The manual paper feed unit 64 is provided mainly for supplying the apparatus main body M with a paper T of a size and type different from the paper T set in the paper feed cassette 52. The manual paper feed unit 64 includes a manual feed tray 65 that forms a part of the front surface of the apparatus main body M in the closed state, and a paper feed roller 66. The manual feed tray 65 is attached at its lower end to the apparatus body M in the vicinity of the paper feed roller 66 so as to be rotatable (openable and closable). The paper T is placed on the open manual feed tray 65. The paper feed roller 66 feeds the paper T placed on the open manual feed tray 65 to the manual feed path La.

  A paper discharge unit 50 is provided on the upper side of the apparatus main body M. The paper discharge unit 50 discharges the paper T to the outside of the apparatus main body M by the third roller pair 53. Details of the paper discharge unit 50 will be described later.

  The conveyance path L for conveying the paper T is a first conveyance path L1 from the cassette paper feeding unit 51 to the transfer nip N, a second conveyance path L2 from the transfer nip N to the fixing unit 9, and a discharge from the fixing unit 9. A third conveyance path L3 to the section 50, a manual conveyance path La that joins the paper supplied from the manual sheet feeding unit 64 to the first conveyance path L1, and a third conveyance path L3 from the downstream side to the upstream side. And a return transport path Lb that reverses the front and back and returns the sheet to the first transport path L1.

Moreover, the 1st junction part P1 and the 2nd junction part P2 are provided in the middle of the 1st conveyance path L1. A first branch portion Q1 is provided in the middle of the third transport path L3.
The first joining part P1 is a joining part where the manual feed path La joins the first transport path L1. The second junction P2 is a junction where the return conveyance path Lb merges with the first conveyance path L1.
The first branch portion Q1 is a branch portion where the return transport path Lb branches from the third transport path L3, and includes a first roller pair 54a and a second roller pair 54b. One roller of the first roller pair 54a and one roller of the second roller pair 54b are combined.

  In the middle of the first transport path L1 (specifically, between the second joining portion P2 and the transfer roller 8), a sensor for detecting the paper T, skew (oblique paper feeding) correction of the paper T, and an image A registration roller pair 80 for aligning the timing of forming the toner image in the forming unit GK and the conveyance of the paper T is disposed. The sensor is disposed immediately before the registration roller pair 80 in the transport direction of the paper T (upstream in the transport direction). The registration roller pair 80 conveys the paper T by performing the above-described correction and timing adjustment based on detection signal information from the sensor.

The return conveyance path Lb is a conveyance path that is provided so that the opposite surface (unprinted surface) to the surface that has already been printed faces the photosensitive drum 2 when performing duplex printing on the paper T.
According to the return conveyance path Lb, the paper T conveyed from the first branching section Q1 to the paper discharge section 50 side by the first roller pair 54a is reversed and returned to the first conveyance path L1 by the second roller pair 54b. , And can be conveyed to the upstream side of the pair of registration rollers 80 arranged on the upstream side of the transfer roller 8. A predetermined toner image is transferred onto the unprinted surface at the transfer nip N on the paper T that is reversed upside down by the return conveyance path Lb.

  A paper discharge unit 50 is formed at the end of the third transport path L3. The paper discharge unit 50 is disposed on the upper side of the apparatus main body M. The paper discharge unit 50 opens toward the right side of the apparatus main body M (the right side in FIG. 1, the manual paper feed unit 64 side). The paper discharge unit 50 discharges the paper T conveyed through the third conveyance path L3 to the outside of the apparatus main body M by the third roller pair 53.

On the opening side of the paper discharge unit 50, a paper discharge stacking unit M1 is formed. The paper discharge stacking unit M1 is formed on the upper surface (outer surface) of the apparatus main body M. The paper discharge stacking unit M1 is a part formed by the upper surface of the apparatus main body M being depressed downward. The bottom surface of the paper discharge stacking unit M1 constitutes a part of the top surface of the apparatus main body M. In the paper discharge stacking unit M1, sheets T formed with a predetermined toner image and discharged from the paper discharge unit 50 are stacked and stacked.
A sheet detection sensor is disposed at a predetermined position in each conveyance path.

Next, the functional configuration of the printer 1 will be described. FIG. 2 is a block diagram illustrating a functional configuration of the printer 1. FIG. 3 is a diagram illustrating an example of the first condition data. FIG. 4 is a diagram illustrating an example of the second condition data.
As shown in FIG. 2, the printer 1 includes the above-described components (photosensitive drum 2, charging unit 10, laser scanner unit 4, developing device 16, transfer roller 8, and drum cleaning unit 11). Note that the description of the components described with reference to FIG. 1 is omitted.
Furthermore, the printer 1 includes a temperature / humidity sensor 100 as a temperature / humidity measurement unit, a storage unit 110, an interface unit 120, and a control unit 130 in addition to the above-described components.

The temperature / humidity sensor 100 measures temperature and humidity. The temperature / humidity sensor 100 measures the temperature and humidity outside the printer 1. When the temperature and humidity sensor 100 measures temperature and humidity, it stores each data in the storage unit 110.
The temperature / humidity sensor 100 can also intermittently measure temperature and humidity at predetermined time intervals. Thereby, the processing load of the control unit 130 is reduced.

  The storage unit 110 stores temperature / humidity data and condition data. The temperature / humidity data is data related to temperature and humidity measured by the temperature / humidity sensor 100. The condition data is data relating to conditions when cleaning is performed using the drum cleaning unit 11.

  In the present embodiment, there are two condition data stored in the storage unit 110. The first condition data shown in FIG. 3 is data used for determining whether or not a first cleaning described later is performed. The second condition data shown in FIG. 4 is data used for determining whether or not second cleaning described later is performed. That is, in the first condition data and the second condition data, it is determined whether or not the photosensitive drum 2 is to be cleaned based on the relationship between the temperature and the humidity measured by the temperature / humidity sensor 100. It defines the conditions used for.

  In the first condition data and the second condition data described above, when “None” is described at a location corresponding to a predetermined temperature and a predetermined humidity, the photosensitive drum 2 is not cleaned. Further, in the first condition data and the second condition, when a number (for example, “72”) is written in a location corresponding to the predetermined temperature and the predetermined humidity, the predetermined temperature and the predetermined condition If the humidity has continued for that number of times (for example, 72 hours), the photosensitive drum 2 is cleaned.

  The interface unit 120 is connected to an external device (for example, a personal computer) installed outside the printer 1.

The control unit 130 functions as a mode setting unit 131, a determination unit 132, and an execution control unit 133.
The mode setting unit 131 sets the printer 1 to one of the image forming mode and the power saving mode. The image forming mode is a mode in which the toner image formed on the surface of the photosensitive drum 2 can be transferred to the paper T. That is, the image forming mode is a mode in which an image can be formed on the paper T, and the photosensitive drum 2, the laser scanner unit 4, the developing device 16, the transfer roller 8, and the like are operated based on the control of the control unit 130. It is a mode that can be made to. The power saving mode is a mode in which the power consumed by the printer 1 is less than that in the image forming mode. That is, the power saving mode is a mode in which an image is not formed on the paper T, and the photosensitive drum 2, the laser scanner unit 4, the developing device 16, the transfer roller 8, and the like are not operated. The power saving mode may be referred to as a sleep mode.

  For example, when no image information is input from the external device via the interface unit 120 for a predetermined time, the mode setting unit 131 sets the power saving mode. For example, when image information is input from an external device via the interface unit 120 after setting the power saving mode, the mode setting unit 131 sets the image forming mode.

  The determination unit 132 uses the drum cleaning unit 11 based on temperature and humidity data related to temperature and humidity measured by the temperature and humidity sensor 100 when the mode setting unit 131 sets the power saving mode to the image forming mode. To determine whether or not to perform cleaning. That is, the determination unit 132 refers to the condition data (first condition data and second condition data) stored in the storage unit 110 when the mode setting unit 131 sets the power saving mode to the image forming mode. Whether or not the photosensitive drum 2 is to be cleaned is determined according to the temperature and humidity based on the temperature and humidity data.

  For example, the determination unit 132 determines whether the temperature and humidity based on the temperature / humidity data correspond to the first condition data, and then determines whether the temperature and humidity correspond to the second condition data. Judging. The determination unit 132 performs cleaning when the temperature and humidity do not correspond to either the first condition data or the second condition data (when the location corresponding to the temperature and humidity is “None”). Judge not to do. If the determination unit 132 determines that the temperature and humidity correspond to the first condition data but does not correspond to the second condition data, the determination unit 132 determines to perform first cleaning described later. If the determination unit 132 determines that the temperature and humidity correspond to both the first condition data and the second condition data, the determination unit 132 determines to perform second cleaning described later.

  As an example, when the temperature based on the temperature / humidity data is 8 ° C. and the humidity is 20%, the determination unit 132 refers to the condition data and determines that the photosensitive drum 2 is not cleaned. As an example, when the temperature based on the temperature / humidity data is 17 ° C., the humidity is 20%, and the temperature and the duration of the humidity are 60 hours, the determination unit 132 refers to the condition data. Then, it is determined that the first cleaning of the photosensitive drum 2 is to be performed, as it corresponds to the first condition data. Further, as an example, when the temperature based on the temperature / humidity data is 35 ° C., the humidity is 95%, and the temperature and the duration of the humidity are 5 hours, the determination unit 132 refers to the condition data. Then, it is determined that the second cleaning of the photosensitive drum 2 is performed, assuming that both the first condition data and the second condition data are applicable.

  Here, the determination unit 132 obtains the average temperature and the average humidity from the temperature and humidity measured by the temperature and humidity sensor 100 while the mode setting unit 131 is set to the power saving mode, and data on the average temperature and the average humidity. Is preferably temperature / humidity data. That is, when determining whether or not to perform cleaning, the determination unit 132 first reads temperature / humidity data from the storage unit 110. The determination unit 132 extracts data measured while the power saving mode is set from the read temperature and humidity data. The determination unit 132 obtains an average temperature and an average humidity while the power saving mode is set based on the extracted data. Then, the determination unit 132 determines whether or not the photosensitive drum 2 is to be cleaned based on the average temperature and the average humidity, using the data related to the average temperature and the average humidity as temperature and humidity data. Thus, even when the temperature and humidity of the environment in which the printer 1 is arranged fluctuate while the printer 1 is set to the power saving mode, the determination unit 132 determines whether or not to clean the photosensitive drum 2. It can be judged accurately.

  The execution control unit 133 causes the surface of the photosensitive drum 2 to be cleaned using the drum cleaning unit 11 when the determination unit 132 determines that cleaning is to be performed. In other words, the execution control unit 133 executes either the first cleaning or the second cleaning according to the temperature / humidity data. The first cleaning is performed using the drum cleaning unit 11 by rotating the photosensitive drum 2 without substantially supplying toner from the developing device 16 to the photosensitive drum 2 during the first time. The surface of the drum 2 is cleaned. In the second cleaning, toner is supplied from the developing unit 16 to the surface of the photosensitive drum 2 and the photosensitive drum 2 is rotated for a second time longer than the first time. Utilizing this, the surface of the photosensitive drum 2 is cleaned.

  Specifically, when the determination unit 132 determines that the first cleaning is to be performed, the execution control unit 133 controls the photosensitive drum 2 and the like to execute the first cleaning. The first cleaning is executed when the influence of a defect that occurs on the image formed on the paper T is small. In the first cleaning, the ionic conductive agent attached to the surface of the photosensitive drum 2 can be reliably removed by idling the photosensitive drum 2 for the first time. The first time is, for example, about 15 seconds to 1 minute, and is about 30 seconds as a more specific example. The fact that toner is not substantially supplied to the photosensitive drum 2 means that the toner is not supplied from the developing device 16 to the photosensitive drum 2 at all, and an amount of toner that does not hinder the effect of the present invention is applied to the developing device 16. To the photosensitive drum 2 is also included.

  If the execution control unit 133 determines that the second cleaning is to be performed by the determination unit 132, the execution control unit 133 controls the photosensitive drum 2, the developing device 16, and the like to execute the second cleaning. The second cleaning is executed when there is a large influence of a problem that occurs on the image formed on the paper T. An abrasive (for example, titanium oxide, etc.) for polishing the surface of the photosensitive drum 2 is externally added to the toner. In the second cleaning, the toner is supplied to the photosensitive drum 2 and the photosensitive drum 2 is idled for a second time longer than the first time, so that the ionic conduction adhered to the surface of the photosensitive drum 2 is achieved. The agent can be surely removed. The second time is, for example, about 90 seconds to 5 minutes, and as a more specific example, is about 2 minutes. That is, the second time is about 1.5 to 10 times as long as the first time, and more specifically, is about four times as long as the first time.

Next, a general operation of the printer 1 will be briefly described with reference to FIG.
First, a case where single-sided printing is performed on the paper T stored in the paper feed cassette 52 will be described.
The paper T accommodated in the paper feed cassette 52 is sent out to the first transport path L1 by the forward feed roller 61 and the paper feed roller pair 63, and then the registration rollers via the first junction P1 and the first transport path L1. Transported to pair 80.
In the registration roller pair 80, skew correction of the paper T and timing adjustment with the toner image are performed.

The paper T discharged from the registration roller pair 80 is introduced between the photosensitive drum 2 and the transfer roller 8 (transfer nip N) via the first conveyance path L1. A toner image is transferred onto the paper T between the photosensitive drum 2 and the transfer roller 8.
Thereafter, the paper T is discharged from between the photosensitive drum 2 and the transfer roller 8, and the fixing nip between the heating rotator 9a and the pressure rotator 9b in the fixing unit 9 via the second conveyance path L2. To be introduced. Then, the toner TN is melted in the fixing nip, and the toner TN is fixed on the paper T.

Next, the paper T is transported to the paper discharge unit 50 through the third transport path L3 by the first roller pair 54a, and is discharged from the paper discharge unit 50 to the paper discharge stacking unit M1 by the third roller pair 53.
In this way, single-sided printing of the paper T stored in the paper feed cassette 52 is completed.

  When single-sided printing is performed on the paper T placed on the manual feed tray 65, the paper T placed on the manual feed tray 65 is sent out to the manual feed path La by the paper feed roller 66, and then the first joining portion. It is conveyed to the registration roller pair 80 via P1 and the first conveyance path L1. Subsequent operations are the same as the one-side printing operation of the paper T accommodated in the paper feed cassette 52 described above, and a description thereof will be omitted.

Next, the operation of the printer 1 when performing duplex printing will be described.
In the case of single-sided printing, as described above, the paper T on which single-sided printing has been performed is discharged from the paper discharge unit 50 to the paper discharge stacking unit M1, and the printing operation is completed.
On the other hand, when performing double-sided printing, the paper T on which single-sided printing has been performed is reversed from the time of single-sided printing and conveyed again to the registration roller pair 80 via the return conveyance path Lb. Then, double-sided printing is performed on the paper T.

  Specifically, the operation is the same as the above-described single-sided printing operation until the paper T on which single-sided printing has been performed is discharged from the paper discharge unit 50 by the third roller pair 53. Thus, in the case of double-sided printing, the rotation of the third roller pair 53 is stopped and rotated in the reverse direction in a state where the paper T on which single-sided printing has been performed is held by the third roller pair 53. When the third roller pair 53 is thus rotated in the reverse direction, the paper T held by the third roller pair 53 moves in the reverse direction (from the paper discharge unit 50 to the first branching unit Q1) along the third transport path L3. Transported in the direction of heading).

  As described above, when the paper T is transported in the reverse direction on the third transport path L3, it is introduced into the second roller pair 54b (not the first roller pair 54a). Then, the paper T joins the first transport path L1 via the return transport path Lb and the second joining portion P2. Here, the paper T is turned upside down from the one-side printing.

  Further, the paper T is corrected or adjusted by the registration roller pair 80 and is introduced between the photosensitive drum 2 and the transfer roller 8 through the first conveyance path L1. Since the unprinted surface of the sheet T passes through the return conveyance path Lb and faces the photosensitive drum 2, the toner image is transferred to the unprinted surface, and as a result, duplex printing is performed.

  Next, a characteristic operation of the printer 1 will be described with reference to FIG. FIG. 5 is a flowchart for explaining a characteristic operation of the printer 1.

  In step ST1, the control unit 130 (mode setting unit 131) sets the printer 1 to the image forming mode. For example, when the control unit 130 (mode setting unit 131) is set to the power saving mode and image information is input from an external device via the interface unit 120, the printer 1 is set to the image forming mode. Set.

  In step ST <b> 2, the control unit 130 (determination unit 132) acquires temperature / humidity data based on reading the temperature / humidity data stored in the storage unit 110.

  In step ST <b> 3, the control unit 130 (determination unit 132) refers to the condition data stored in the storage unit 110, and performs cleaning as to whether or not to clean the photosensitive drum 2 based on the temperature / humidity data. In this case, it is determined which of the first cleaning and the second cleaning is performed. When performing the first cleaning, the control unit 130 advances the process to step ST4. In the case of performing the second cleaning, the control unit 130 advances the process to step ST5. When cleaning is not performed, the control unit 130 ends the process.

  In step ST4, the control unit 130 (execution control unit 133) causes the first cleaning to be executed. That is, the control unit 130 (execution control unit 133) controls the photosensitive drum 2 and the like, so that the developing device 16 does not substantially supply toner to the photosensitive drum 2 and the photosensitive drum 1 for the first time. The body drum 2 is idled and the surface of the photosensitive drum 2 is cleaned by the drum cleaning unit 11. After step ST4, the control unit 130 ends the process.

  In step ST5, the control unit 130 (execution control unit 133) controls the developing device 16 so as to supply a predetermined amount of toner to the photosensitive drum 2. The control unit 130 (execution control unit 133) may control the developing device 16 so that the toner is supplied to the photosensitive drum 2 at a time before the process of step ST6 described later is performed, and the process of step ST6 is performed. The developing device 16 may be controlled so that the toner is supplied to the photosensitive drum 2 intermittently or continuously during the operation.

  In step ST <b> 6, the control unit 130 (execution control unit 133) controls the photosensitive drum 2 and the like to cause the photosensitive drum 2 to rotate idly for the second time, and the drum cleaning unit 11 performs the photosensitive operation. The surface of the body drum 2 is cleaned. After step ST6, the control unit 130 ends the process.

According to this embodiment, the following effects are produced, for example.
The printer 1 uses the drum cleaning unit 11 based on temperature and humidity data related to temperature and humidity measured by the temperature and humidity sensor 100 when the mode setting unit 131 sets the power saving mode to the image forming mode. A determination unit 132 that determines whether or not to perform cleaning, and an execution control unit 133 that executes cleaning of the surface of the photosensitive drum 2 using the drum cleaning unit 11 when the determination unit 132 determines that cleaning is to be performed. And comprising. As a result, the printer 1 cleans the photosensitive drum 2 when there is a possibility that the charging roller 10a may bleed, so that the possibility of a defect occurring in the image formed on the paper T can be reduced. .

Further, the printer 1 causes either the first cleaning or the second cleaning to be executed according to the temperature / humidity data. In the first cleaning, the photosensitive drum 2 is rotated using the drum cleaning unit 11 by rotating the photosensitive drum 2 without substantially supplying toner from the developing unit to the photosensitive drum 2 during the first time. The surface of No. 2 is cleaned. The second cleaning uses the drum cleaning unit 11 by supplying toner from the developing unit to the surface of the photosensitive drum 2 and rotating the photosensitive drum 2 for a second time longer than the first time. Thus, the surface of the photosensitive drum 2 is cleaned.
Accordingly, the printer 1 can perform appropriate cleaning according to the state of a problem that may occur in an image formed on the paper. In other words, since the printer 1 performs either the first cleaning or the second cleaning, the possibility that a defect occurs in the image can be further reduced. Further, when the first cleaning is executed, the printer 1 does not substantially supply toner from the developing unit 16 to the photosensitive drum 2, so that resources can be saved.

  In addition, the printer 1 obtains the average temperature and the average humidity from the temperature and humidity measured by the temperature and humidity sensor 100 while the mode setting unit 131 is set to the power saving mode, and obtains data on the average temperature and the average humidity as the temperature. Use humidity data. While the printer 1 is set to the power saving mode, the temperature and humidity of the environment in which the printer 1 is arranged may fluctuate. Even in such a case, the printer 1 can accurately determine whether or not to clean the photosensitive drum 2. Further, when it is determined that the photosensitive drum 2 is to be cleaned, the printer 1 can accurately determine whether to perform the first cleaning or the second cleaning.

As mentioned above, although preferred embodiment was described, this invention can be implemented with a various form, without being limited to embodiment mentioned above.
In the present embodiment, a direct transfer method in which the toner image formed on the surface of the photosensitive drum 2 is directly transferred to the paper T is used. However, the present invention is not limited to this embodiment, and after the toner image formed on the surface of the photosensitive drum is primarily transferred to the intermediate transfer belt, the toner image is transferred from the intermediate transfer belt to the sheet. An indirect transfer method may be used.
In the present embodiment, the monochrome printer 1 is described as the image forming apparatus. However, the present invention is not limited to this, and the image forming apparatus may be a color printer, a color copier, a facsimile, or a complex machine thereof. .

DESCRIPTION OF SYMBOLS 1 ... Printer (image forming apparatus), 2 ... Photosensitive drum (image carrier), 4 ... Laser scanner unit (exposure part), 8 ... Transfer roller (transfer part), 10 ... Charging part, 10a ... Charging roller (charging) Member), 11 ... drum cleaning unit (cleaning unit), 16 ... developing device (developing unit), 100 ... temperature / humidity sensor (temperature / humidity measuring unit), 131 ... mode setting unit, 132 ... determination unit, 133 ... execution control unit

Claims (4)

An image carrier;
A charging unit for charging the surface of the image carrier;
An exposure unit that forms an electrostatic latent image on the surface of the image carrier by irradiating light on the surface of the charged image carrier;
A developing unit that develops the electrostatic latent image formed by the exposure unit with toner by supplying toner to the image carrier and forms a toner image on the surface of the image carrier;
A transfer unit that directly or indirectly transfers a toner image formed on the surface of the image carrier to a transfer material;
A cleaning unit that is disposed downstream of the transfer unit in the rotational direction of the image carrier and that cleans the surface of the image carrier;
A temperature and humidity measuring unit for measuring temperature and humidity;
An image forming mode in which a toner image formed on the surface of the image carrier can be transferred to a transfer material, and a power saving mode in which power consumed in the image forming apparatus is less than that in the image forming mode. A mode setting unit for setting the image forming apparatus in any of them,
When the mode setting unit sets the image forming mode from the power saving mode, cleaning is performed using the cleaning unit based on temperature and humidity data measured by the temperature and humidity measuring unit. A determination unit for determining whether or not to perform;
An execution control unit for performing cleaning of the surface of the image carrier using the cleaning unit when the determination unit determines to perform cleaning;
An image forming apparatus comprising: The execution control unit
During the first time, the surface of the image carrier is cleaned using the cleaning unit by rotating the image carrier without substantially supplying toner from the developing unit to the image carrier. A first cleaning to be performed;
The toner is supplied from the developing unit to the surface of the image carrier, and the image carrier is rotated for a second time longer than the first time so that the image carrier is utilized by using the cleaning unit. A second cleaning for cleaning the surface of the body;
The image forming apparatus according to claim 1, wherein any one of the above is executed according to the temperature and humidity data. The determination unit obtains an average temperature and an average humidity from the temperature and humidity measured by the temperature and humidity measurement unit while being set to the power saving mode by the mode setting unit, and obtains data on the average temperature and the average humidity. The image forming apparatus according to claim 1, wherein the image forming apparatus uses temperature and humidity data. The charging unit includes a charging member that contacts the surface of the image carrier,
The image forming apparatus according to claim 1, wherein a conductive member containing an ionic conductive agent is disposed on a surface of the charging member.

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