JP2006151647A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide technique, capable of forming images on unprinted surfaces securely without labor even to face-down sheets in a mixed bundle of face-up and face-down sheets. <P>SOLUTION: An image forming device 110 determines if a surface of paper P2 where images are to be printed is unprinted or already printed by a sensor 32. If it is unprinted, it is carried on a carrying passage S1 inversely while maintaining it face direction, and the paper P2 is stored in a tray 31. If it is already printed, the paper P2 is carried from the carrying passage S1 onto a carrying passage S3 by carrying rolls 34f, 34g, and 34h, the face side of the paper P2 is reversed, and it is stored in the tray 31a. In printing images, the image forming device 110 uses paper in the tray 31a. Thereby unprinted surfaces of the paper P2 can be printed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus, and more particularly to a technique for forming an image on a so-called backing paper that has already been printed on one side.

  In view of dealing with environmental issues and reusing resources, in the workplace where a large amount of paper is used in copiers and printers, etc., recording paper (hereinafter referred to as “recording paper”) that has been used with images formed on only one side. An image is formed on a surface on which an image is not formed and reused. Here, when using the back paper in image printing, the user must align the front and back of the back paper and store the paper in the paper feed tray so that the side on which the image is formed becomes an unprinted surface. If the amount of backing paper to be used is small, the burden on the user is small, but if it is large, the burden on the user is large. Thus, the following techniques are available as techniques for effectively using the backing paper without imposing a burden on the user.

The image forming apparatus disclosed in Patent Document 1 includes a reflective optical sensor in the vicinity of a paper feed tray. This optical sensor irradiates the paper in the conveyance path with light, and determines whether the surface to be printed from now on is the printed surface or the unprinted surface based on the reflected light reflected. Then, the image forming apparatus discharges the sheet if the surface is already printed, and prints the image if the surface is not printed. Therefore, even if the back paper with the front and back mixed by the user is stored in the paper feed tray, it can be prevented from printing on the printed surface, and the back paper can be easily reused. In the technique disclosed in Patent Document 2, a tray is partitioned into a paper feed side and a paper discharge side by a partition mechanism, and unused paper is stored in the paper feed side. When printing, the image forming apparatus uses unused paper stored on the paper supply side, and stores the printed paper on the paper discharge side of the tray. Since the back paper stored on the paper discharge side is aligned in the front and back direction, the user can reuse the back paper by moving the back paper bundle to the paper feed side of the tray.
JP-A-9-96927 Japanese Patent Laid-Open No. 11-301933

  However, in the technique of Patent Document 1, if the surface to be printed is an already printed surface, the backing paper is discharged. Therefore, if the user wants to use the discharged backing paper, the user again puts it in the paper feed tray. It had to be stored, requiring user trouble. Japanese Patent Application Laid-Open No. 2003-228561 discloses a technique for discharging and feeding paper in the same tray. However, since the paper first stored on the paper feeding side by the user must be an unused paper, It was not possible to use it for a stack of back paper that was stocked in a mixed state.

  The present invention has been made in view of such a background, and an image is reliably formed on an unprinted surface without taking time and effort even for a bundle of back sheets that are bundled in a state where both front and back sides are mixed. The purpose is to provide technology that can do things.

  In order to solve the above-described problems, the present invention provides an image forming apparatus having an image forming unit that forms an image on a recording sheet according to image data, first and second recording sheet storage units for storing a recording sheet to be conveyed, Whether or not an image has already been formed on the image forming surface on which the image is to be formed by the image forming unit with respect to the recording sheet conveyed from the first recording sheet storing unit is determined upstream of the image forming unit. And detecting means for detecting, and when an image is detected on the image forming surface by the detecting means, the recording sheet is turned upside down and stored in the second recording sheet storing means, and the detecting means detects the image forming surface. An image forming apparatus comprising: a storing and conveying unit that stores the recording sheet in the second recording sheet storing unit without reversing the front and back of the recording sheet when an image is not detected To provide a location.

  According to the image forming apparatus of the present invention, the recording sheet stored in the first recording sheet storage unit by the user is transported to the detection sensor that detects the image by the transport unit. When the presence or absence of an image is detected by the detection sensor and no image is detected, the recording sheet is stored in the second recording sheet storage unit by the storage and conveyance unit while maintaining the front and back direction of the recording sheet. On the other hand, when the image is detected by the detection sensor, if the orientation is as it is, the image is printed on the already printed surface, and the already printed image and the image to be printed are overlapped. The sheet is reversed and stored in the second recording sheet storage means.

  The present invention also relates to a storage unit that stores a recording sheet, an image forming unit that forms an image in accordance with image data on the recording sheet transported from the storage unit, and a recording sheet transported from the recording sheet storage unit. Detecting means for detecting whether or not an image has already been formed on the image forming surface on which the image is to be formed by the image forming means, and an image on the recording sheet by the detecting means. An image forming apparatus comprising: a reversing conveying unit that reverses the front and back of the recording sheet and conveys the recording sheet to the image forming unit before an image is formed on the recording sheet by the image forming unit. To do.

  According to the above-described image forming apparatus, when no image is detected on the image forming side by the detection sensor, the image forming apparatus conveys the recording sheet to the image forming unit while maintaining the front and back directions of the recording sheet. Then, image formation is performed. On the other hand, if an image is detected on the image forming side by the detection sensor, the recording sheet is conveyed to the image forming unit by reversing the front and back of the recording sheet by the reverse conveying unit before image printing is performed. Print an image.

  In a preferred aspect of the present invention, the second recording sheet storage means has a paper feed roller, and when the recording sheet is discharged from the second recording sheet storage means, the paper feed roller When the recording sheet is stored in the second recording sheet storage unit in a pressed state, the paper feed roller is in a released state with respect to the recording sheet.

The first embodiment of the present invention will be described below.
(1) Apparatus Configuration FIG. 1 is a diagram illustrating an overall configuration of an image forming apparatus 100 according to the embodiment. The image forming apparatus 100 is, for example, a color printer, a color copying machine, or a multifunction machine having a plurality of these functions. As shown in FIG. 1, the configuration of the image forming apparatus 100 is roughly divided into an image forming unit 10, an image reading unit 20, and a paper supply unit 30. Further, the image forming apparatus 100 includes a user interface device 50 for the user to perform various operations. The user interface device 50 includes a liquid crystal display that functions as a touch panel, and the user can perform various operations by touching the liquid crystal display.

  The image reading unit 20 includes a document feeder 21 and an optical system member 22 composed of a CCD (Charge Coupled Device) or the like. The image reading unit 20 reads an image of a document placed on a platen glass (not shown) by the document feeder 21 using the optical system member 22 and generates image data representing the read image. The image forming apparatus 100 is connected to a network such as a LAN (Local Area Network) via a communication interface (not shown), and image data transmitted from a host device such as a personal computer or a server machine via the LAN. Receive. The image forming unit 10 performs image forming processing based on the image data generated by the image reading unit 20 and the image data received via the communication interface.

  Next, the image forming unit 10 includes a photosensitive drum 11, a charging device 12, an exposure device 13, a rotary developing device 14, a cleaning device 15, an intermediate transfer belt 16, a support roll 17, and a primary transfer roll. 18, a secondary transfer roll 19, a counter roll 40, a conveyance belt 41, and a fixing device 42. A photosensitive layer is formed on the outer peripheral surface (drum surface) of the photosensitive drum 11, and the photosensitive drum 11 is rotated in the direction of arrow a in the drawing by a driving mechanism (not shown). The charging device 12 is, for example, a roll-type charging device or a corotron-type charging device, and uniformly charges the surface of the photosensitive drum 11 to a predetermined potential. The exposure device 13 irradiates the uniformly charged photosensitive drum 11 with laser light modulated in accordance with image data to form an electrostatic latent image on the surface of the photosensitive drum 11.

  The rotary developing device 14 includes developing units 14Y, 14M, 14C, and 14K that respectively store toners (developers) of respective colors of Y (yellow), M (magenta), C (cyan), and K (black). Yes. When the rotary developing device 14 is rotated in the direction of the arrow b in the figure by a driving mechanism (not shown), the four developing units 14Y, 14M, 14C, and 14K are sequentially moved to positions close to the photosensitive drum 11. It is done. Then, each toner accommodated in each developing unit 14Y, 14M, 14C, 14K is electrically transferred to an electrostatic latent image corresponding to each color, whereby a toner image is formed on the surface of the photosensitive drum 11. It is formed. FIG. 1 shows a state in which the developing unit 14 </ b> Y that accommodates yellow is in a position close to the photosensitive drum 11 and a yellow image is formed on the surface of the photosensitive drum 11.

  The intermediate transfer belt 16 is an endless belt member, and its inner peripheral surface is stretched by a plurality of support rolls 17 (two in FIG. 1), a primary transfer roll 18 and a secondary transfer roll 19, It is moved around in the direction of arrow c. The primary transfer roll 18 transfers (primary transfer) the toner image formed on the surface of the photosensitive drum 11 to the outer peripheral surface of the intermediate transfer belt 16 while sandwiching the intermediate transfer belt 16 with the photosensitive drum 11. A cleaning device 15 provided in the vicinity of the photosensitive drum removes toner remaining on the surface of the photosensitive drum 11 after the primary transfer. The secondary transfer roll 19 transfers (secondary transfer) the toner image transferred to the outer peripheral surface of the intermediate transfer belt 16 to a sheet in a nip region formed between the opposing roll 40. The toner remaining on the surface of the intermediate transfer belt 16 after the secondary transfer is removed by the belt cleaner 23.

  The fixing device 42 includes a fixing roll 42a and a pressure roll 42b that face each other. The fixing device 42 fixes the toner image on the sheet by rapidly heating the sheet onto which the toner image has been secondarily transferred while applying pressure by the fixing roll 42a and the pressure roll 42b. After this fixing process, the paper is discharged onto the paper discharge tray 46 by the transport rollers 43a and 43b.

  The paper supply unit 30 includes paper supply sources such as paper trays 31a and 31b, and transport rolls 34a to 34h. As a conveyance path for conveying a sheet from a sheet supply source, there are a conveyance path S1 indicated by a dotted line in the drawing, and S2 indicated by a dashed line. The conveyance path S1 is a series of paths from the paper supply source to the conveyance roll 34a, the conveyance rolls 34b and 34c, and further 34d and 34e, and to the discharge port. The conveyance path S2 is a series of paths from the exit side of the fixing device 42 through the conveyance roll 34f to the conveyance rolls 34g and 34h and the conveyance roll 34c on the conveyance path S1.

  Next, the configuration of the control system of the image forming apparatus 100 will be described with reference to the block diagram of FIG. In FIG. 2, the control unit 110 includes, for example, an MPU (Micro Processor Unit) and various application specific ASICs (Application Specific Integrated Circuits), and performs image formation according to a control program stored in the storage unit 120. The operations of the image forming unit 10, the image reading unit 20, and the paper supply unit 30 of the apparatus 100 are controlled.

  The paper supply unit 30 includes a sensor 32, and the control unit 110 detects the paper fed from the paper supply source (tray 31 a or tray 31 b) on the sensor side based on the output signal from the sensor 32. Monitors whether an image is printed. That is, a sensor 32 that detects whether an image is printed on a sheet is attached between the transport rollers 34b and 34c. In the present embodiment, the sensor 32 is attached so as to detect the image of the lower side when the sheet conveyed by the conveyance path is stored in the sheet tray 31a or 31b. The sensor 32 includes a light source 32A that irradiates light to the paper (for example, an LED) and a light receiving element 32B that detects reflected light (for example, a photodiode), and an image on the paper based on the amount of received light. The presence or absence of is detected. When the sensor 32 detects that an image is printed, the control unit 110 controls the paper supply unit 30 so that the front and back of the paper are reversed (details will be described later).

(2) Operation Example Next, the operation of this embodiment will be described with reference to FIG. In the present embodiment, the user mixes the front and back sheets of paper in the tray 31b.

  First, the control unit 110 controls the paper supply unit 30 to place the paper feed roll 312b against the paper P2. Then, a motor (not shown) is driven to rotate the paper feed roll 311b and the paper feed roll 312b to send the paper P2 to the paper transport path S1 (step S10). When the paper P2 is conveyed to the position of the sensor 32, the control unit 110 detects the presence / absence of an image on the paper P2 by the sensor 32 (step S12). At this time, as shown in FIGS. 4A and 4B, the transport rollers 34c and 34d are rotated in the d and d 'directions to transport the paper.

  If no image is detected on the paper P2 (step S14; NO), the paper P2 is transported in the opposite direction (step S16). Specifically, as shown in FIGS. 4C and 4D, the transport rollers 34c and 34d are rotated in the e and e 'directions to transport the paper. The transport rolls 34a and 34b and the paper feed roll 311a are also rotated in the same e and e 'directions as the transport rolls 34c and 34d to transport the paper P2, and finally the paper P2 is stored in the tray 31a (step S18). . At this time, the paper feed roll 312a is released from the paper P2.

  When an image is detected on the paper P2 (step S14; YES), the control unit 110 transports the paper P2 from the transport roll 34d to the transport roll 34e, and further transports it to the paper transport path S2 (step S22). At this time, the secondary transfer roll 19, the opposing roll 40, the fixing roll 42a, and the pressure roll 42b are released from the paper P2, and are conveyed without printing on the paper P2. Then, the control unit 110 transports the paper P2 from the transport path S2 to the transport roll 34c.

  The process in which the paper P2 is conveyed from the tray 31b to the tray 31a by the control unit 110 is shown in FIGS.

  FIG. 5 illustrates a state in which the paper P2 whose printed surface is facing upward in the tray 31b is conveyed from the tray 31b to the tray 31a. The controller 110 first transports the paper P2 from the tray 31b to the transport path S1, and transports the transport path S1 in the g direction. When transported to the sensor 32, the presence or absence of an image on the surface on the sensor 32 side is detected. In the paper P2 in FIG. 5, since the unprinted surface is on the sensor 32 side, no image is detected. Therefore, the control unit 110 conveys the sheet P2 to the conveyance roll 34d while maintaining the front and back of the sheet P2, and then conveys the sheet P2 in the direction f and stores it in the tray 31a.

  FIG. 6 illustrates a state in which the paper P2 whose printed surface is facing down in the tray 31b is conveyed from the tray 31b to the tray 31a. The controller 110 first transports the paper P2 from the tray 31b to the transport path S1, and transports the transport path S1 in the g direction. When transported to the sensor 32, the presence or absence of an image on the surface of the paper P2 on the sensor 32 side is detected. In FIG. 5, since the sensor 32 side is an already printed surface, an image is detected. Therefore, the control unit 110 conveys the sheet P2 from the conveyance path S1 to the conveyance path S2 in order to reverse the front and back of the sheet P2. Then, when the paper P2 is transported to the transport rolls 34f and 34g on the transport path S2 and further transported from the transport roll 34h to the transport roll 34c, the paper P2 is transported in the f direction on the transport path S1 and stored in the tray 31a.

  By repeating the operation as described above, the sheets stored in the tray 31b in a mixed state as shown in FIG. 7 (a) are uniformly aligned as shown in FIG. 7 (b). Stored in the tray 31a.

  When printing is instructed by the user, the paper is sequentially transported from the tray 31a onto the transport path S1, and an image is printed on the unprinted surface of the paper. Note that the printing instruction may be performed in advance, and in this case, the image forming apparatus 100 starts image printing after performing the operation of aligning the front and back of the paper.

  In this embodiment, it is the tray 31b that stores the back paper with the front and back mixed by the user, and the tray 31a is used to store the back paper with the front and back made uniform by the control unit 110. For example, the touch panel 50 Thus, the user may be able to instruct which tray is the front / back mixed tray and the front / back uniform tray. When such an instruction is given, the image forming apparatus 100 controls the conveyance path based on the instruction from the user.

  In addition, the sensor 32 is configured to detect an image on the lower side when the sheet conveyed by the conveyance path S1 is stored in the sheet 31b. However, the image is printed on the upper side. May be configured to perform upper image detection. Moreover, the structure which performs the image detection of both upper and lower sides may be sufficient. According to this configuration, when images are already printed on both sides of the paper, the images can be detected from both sides at once, so that it is possible to know that the paper cannot be used as a back paper. Based on the detection result, it is possible to control such as immediately discharging such a sheet or warning the user. Therefore, as the paper stored in the tray 31a, it is possible to reliably select the paper on which one side is not printed.

  The control program executed by the control unit 110 described in this embodiment includes a magnetic tape, a magnetic disk, a floppy (registered trademark) disk, an optical recording medium, a magneto-optical recording medium, a CD (Compact Disk) -ROM, and a DVD. (Digital Versatile Disk) can be provided in a state of being recorded on a recording medium such as a RAM.

  As described above, according to the present embodiment, even if a back paper with a mixed front and back is stored in the tray by the user, whether the surface to be printed from now on is a printed surface or an unprinted surface is detected by the sensor. Can be determined. If the printed surface is already printed, the conveyance circuit that reverses the front and back is controlled so that the back paper is conveyed, so that the user can save the trouble of aligning the front and back each time the back paper is stored in the tray.

Next, a second embodiment will be described. Note that the description of the same configuration and operation as in the first embodiment will be omitted.
(1) Apparatus Configuration FIG. 8 is a diagram illustrating an overall configuration of the image forming apparatus 100 according to the embodiment. The paper supply unit 30 includes a transport path S3 indicated by a two-dot chain line in the figure as a transport path for inverting the front and back of the paper. The conveyance path S3 passes from the fixing roll 42a and the pressure roll 42b on the conveyance path S1 through the conveyance rolls 34f and 34i and the conveyance roll 34j, and further from the conveyance roll 34j to the conveyance rolls 34i, 34g, 34h, and 34k. It is a series of routes between.

(2) Operation Example Next, the operation of this embodiment will be described with reference to FIG.

  Here, it is assumed that the tray 31b stores the back paper in which the front and back directions of the paper are mixed by the user.

  If the sheet P2 conveyed to the conveyance path S1 by the control unit 110 is detected by the sensor 32 and no image is detected (step S14; NO), the control unit 110 ends this routine, and the sheet P2 Are conveyed on the conveyance path S1 as they are, and normal image printing is performed.

  When the image is detected (step S14; YES), the control unit 110 transports the paper P2 from the transport path S1 to the transport path S3 (step S30).

  FIG. 10 shows a process in which the sheet P2 is conveyed in the routine from step S10 to step S30.

  The control unit 110 sends the paper P2 from the tray 31b onto the transport path S1. And it conveys to conveyance roll 34b-34e on conveyance path S1, and passes between fixing roll 42a and pressurization roll 42b. At this time, the secondary transfer roll 19, the opposing roll 40, the fixing roll 42a, and the pressure roll 42b are controlled so as to be in a released state with respect to the paper P2. Thereafter, the paper is transported to the transport roll 34f and transported from the transport roll 34f by the transport rolls 34i and 34j in the x1 direction, and then the transport rolls 34i and 34j are rotated in the opposite direction to transport the paper P2 in the x2 direction. . Then, the transport rolls 34i to 34g and 34h are transported to 34k, and then transported to the transport roll 34d.

  When step S30 ends, the control unit 110 ends this routine, transports the sheet P2 as it is from the transport roll 34d onto the transport path S1, and performs normal image printing.

  In this embodiment, in step S30 in FIG. 9, after the paper P2 is transported from the transport path S1 to the transport path S3, normal image printing is performed on the paper P2. However, the image printing is not performed and the tray 31b is used. You may make it store temporarily in trays other than. That is, printing may be performed only when the surface on which an image is to be printed is an unprinted surface, and when the surface is an already printed surface, the front and back surfaces may be reversed and temporarily stored in the tray 31a.

  In the present embodiment, the tray 31b is a tray that stores sheets of paper mixed by the user, but the user may select the tray to be stored using, for example, a touch panel. When such an instruction is given, the image forming apparatus 100 controls the conveyance path based on the instruction from the user.

  As described above, according to the present embodiment, even if a sheet with both front and back sides is stored in the tray, the sensor determines whether there is an image on the side to be printed from now on. Since printing is performed, the user can save the trouble of aligning the front and back each time sheets are stored in the tray.

  Note that the second embodiment described above can be modified in the same manner as the first embodiment described above.

1 is a diagram illustrating a configuration of an image forming apparatus according to a first embodiment of the present invention. 2 is a block diagram illustrating a configuration of a control system of the image forming apparatus. FIG. 3 is a flowchart showing a flow of processing performed by the image forming apparatus. FIG. 6 is a diagram illustrating a rotation direction of a conveyance roll and a conveyance direction of a sheet. FIG. 6 is a diagram illustrating a sheet conveyance path. FIG. 6 is a diagram illustrating a sheet conveyance path. FIG. 10 is a diagram showing that the front and back orientations are uniform when the paper having the front and back orientation mixed in the tray 31b is stored in the tray 31a through the transport path. It is a figure which shows the structure of the image forming apparatus which concerns on 2nd Embodiment of this invention. 2 is a block diagram illustrating a configuration of a control system of the image forming apparatus. FIG. FIG. 6 is a diagram illustrating a sheet conveyance path.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Image forming apparatus, 10 ... Image forming unit, 11 ... Photosensitive drum, 12 ... Charging device, 13 ... Exposure apparatus, 14 ... Rotary developing device, 14Y, 14M, 14C, 14K, 14F ... developer, 16 ... intermediate transfer belt, 18 ... primary transfer roll, 19 ... secondary transfer roll, 20 ... image reading unit, 30 ... paper supply Units 31a, 31b ... paper trays, 34a to 34k ... transport rolls, 32 ... sensors, 42 ... fixing device, 43 ... paper discharge roll, 50 ... user interface device, 110 ... Control unit.

Claims (3)

In an image forming apparatus having image forming means for forming an image according to image data on a recording sheet,
First and second recording sheet storage means for storing the recording sheet to be conveyed;
Whether or not an image has already been formed on the image forming surface on which the image is to be formed by the image forming unit with respect to the recording sheet conveyed from the first recording sheet storing unit is determined upstream of the image forming unit. Detecting means for detecting;
When an image is detected on the image forming surface by the detecting means, the recording sheet is turned upside down and stored in the second recording sheet storing means, and no image is detected on the image forming surface by the detecting means. In this case, the image forming apparatus includes: a storing and conveying unit that stores the recording sheet in the second recording sheet storing unit without reversing the front and back of the recording sheet. Storage means for storing the recording sheet;
Image forming means for forming an image in accordance with image data on a recording sheet conveyed from the storage means;
An upstream side of the image forming unit detects whether an image has already been formed on the image forming surface on which the image is to be formed by the image forming unit with respect to the recording sheet conveyed from the recording sheet storage unit. Detection means;
When the image is detected on the recording sheet by the detection unit, the reverse conveying unit reverses the front and back of the recording sheet and conveys the image to the image forming unit before the image is formed on the recording sheet by the image forming unit. And an image forming apparatus. The second recording sheet storage means has a paper feed roller, and when the recording sheet is discharged from the second recording sheet storage means, the paper feed roller is pressed against the recording sheet, and the second recording sheet storage The image forming apparatus according to claim 1, wherein when the recording sheet is stored in the unit, the paper feed roller is released from the recording sheet.

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