Image forming apparatus and control program

Abstract

To automatically perform image formation adaptively to conveyance properties of even a recording medium in use which does not satisfy product specifications.SOLUTION: An image formation device 10 comprises: a first determination unit 111 which determines the kind of a recording medium based upon sheet physical properties that a media sensor 18 measures; a second determination unit 112 which determines conveyance performance for a recording medium conveyed in a conveyance path 143; and an image formation determination unit 113 which determines whether to perform image formation based upon the conveyance performance that the second determination unit 112 determines when the kind of the recording medium that the first determination unit 111 determines does not satisfy product specification.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus and a control program. [Background technology]

[0002] In recent years, image forming devices such as electrophotographic printers have been widely used in the color printing industry. In the field of PP (production print), which corresponds to the color printing industry, there is a demand for devices that can handle a wider variety of paper types than those used in offices.

[0003] To achieve high-quality printing on these various types of paper, there is a technology that sets the type of paper contained in a paper feed tray and prints under image formation conditions determined according to that setting. For example, in the image forming device disclosed in Patent Document 1, a sensor called a media sensor that automatically identifies the type of paper is placed in the transport path, and the type of paper is automatically identified based on the detection output, and printing is performed under printing conditions appropriate for that type.

[0004] Generally, in an image forming device, paper that can guarantee a certain output quality is defined as paper within the product specifications, and the user selects the type of paper from within the setting range within the product specifications, and printing is performed under image formation conditions that correspond to the selected paper type.

[0005] On the other hand, there are cases where image forming apparatuses are used to print on paper that does not meet the product specifications. For example, paper that does not meet the product specifications has a basis weight of 350 g / m. 2 Although this type of paper is outside the product specifications of many image forming apparatuses, there are also users who print using paper with such a large basis weight (thick paper).

[0006] Patent document 2 discloses an image forming device that, since there is a risk of toner not fixing sufficiently when the paper is outside the product specifications (cardboard) or has a surface treatment, sets an upper limit on the time or number of sheets for such paper outside the product specifications, and, as long as it is within that limit, performs printing under image forming conditions that exceed the upper limit of the normal fixing temperature setting. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Publication No. 2021-59451 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-231910 Summary of the Invention [Problem to be solved by the invention]

[0008] However, using paper outside of product specifications carries certain risks. For example, there is the risk of reduced image quality and problems such as jams. A user familiar with image forming devices, such as a print shop operator, is aware of these risks and can set the optimal settings to balance risk and quality, minimizing risk and mastering the device. However, not all users are knowledgeable, and it is difficult to expect all users to respond in the same way. Furthermore, there are many cases where problems occur due to incorrect specifications without the user even realizing that they are using paper outside of product specifications.

[0009] Furthermore, as in Patent Document 2, it is possible to automatically determine whether the paper is outside the product specifications by using a media sensor inside the device, but in such a case, any paper that does not fall within the product specifications will be uniformly prohibited from printing, which limits the user's options and reduces convenience.

[0010] The present invention has been made in consideration of the above circumstances, and aims to provide an image forming apparatus and a control program that can automatically form images in accordance with the conveying performance, even when a recording medium outside the product specifications is used. [Means for solving the problem]

[0011] The above object of the present invention can be achieved by the following means.

[0012] (1) a paper feed and conveyance unit that feeds and conveys a recording medium to a conveyance path; an image forming unit that forms an image on the recording medium conveyed through the conveyance path; a media sensor disposed on the conveying path upstream of the image forming unit in a conveying direction of the recording medium, the media sensor measuring one or more paper physical properties of the conveyed recording medium; a first determination unit that determines the type of the recording medium based on the paper physical properties measured by the media sensor; a second determination unit that determines the transport performance of the recording medium transported through the transport path; an image formation determination unit that determines whether or not to perform image formation based on the conveying performance determined by the second determination unit when the type of the recording medium determined by the first determination unit is outside of product specifications; An image forming apparatus comprising:

[0013] (2) The image formation determination unit stops image formation by the image forming unit when the type of the recording medium determined by the first determination unit is outside the product specifications. The image forming apparatus described in (1) above, wherein even if the recording medium is of a type outside the product specifications, if the conveying performance determined by the second determination unit satisfies a predetermined performance, image formation is not stopped but image formation is performed on the recording medium of a type outside the product specifications.

[0014] (3) An image forming apparatus as described in (1) or (2) above, wherein the first determination unit determines that the recording medium is of a type outside of product specifications based on at least one of the classifications of the recording medium, such as basis weight, whether or not it is coated, and whether or not it is an envelope, determined by measurement by the media sensor.

[0015] (4) An image forming apparatus according to any one of (1) to (3), wherein the second judgment unit judges whether the conveying performance satisfies a predetermined performance based on the conveying time tx from when the paper feed conveying unit starts feeding the recording medium until the recording medium reaches the detection position of a paper detection sensor located at a predetermined position upstream of the image forming position of the image forming unit on the conveying path.

[0016] (5) An image forming apparatus according to any one of (1) to (3), wherein the second determination unit determines whether the conveying performance satisfies a predetermined performance from the detection result of the drive torque of the drive motor of the paper feed conveying unit in any section from when the paper feed conveying unit starts feeding the recording medium to when the recording medium reaches the detection position of a paper detection sensor located at a predetermined position upstream of the image forming position of the image forming unit on the conveying path.

[0017] (6) When the image formation determination unit stops image formation because the recording medium is a type outside the product specifications, the image formation determination unit executes a purge process in which the recording medium being conveyed is discharged blank outside the apparatus, or a jam detection process in which the recording medium is stopped midway along the conveyance path, An image forming apparatus as described in (4) or (5) above, in which, when image formation is performed even if the recording medium is a type outside the product specifications, the conveying speed and / or fixing control temperature of the recording medium are set as image formation conditions during image formation according to the determined conveying performance, and the image formation is performed under the set image formation conditions.

[0018] (7) The image formation determination unit determines the document type to be formed on the recording medium from the color mode and / or graphic or text information included in the print data, The image forming apparatus according to (6) above, wherein the image formation determining unit sets the image forming conditions in accordance with the determined document type in addition to the conveying performance.

[0019] (8) When image formation is performed on the recording medium of a type outside the product specifications, information on the occurrence of a jam of the conveyed recording medium is stored in a storage unit as history data in association with the type of the recording medium determined by the first determination unit, When the storage unit has history data associated with the type of recording medium determined by the first determination unit, the image formation determination unit: An image forming apparatus according to any one of (1) to (7) above, wherein if the history of jam occurrence in the historical data is less than a predetermined threshold, image formation is performed based on the conveying performance determined by the second judgment unit, and if the history of jam occurrence is equal to or greater than the predetermined threshold, image formation is stopped regardless of the judgment result of the second judgment unit.

[0020] (9) When image formation is performed on the recording medium of a type outside the product specifications in one print job, the image formation determination unit stores the type of the recording medium determined by the first determination unit as history data in a storage unit in association with jam occurrence information of the conveyed recording medium and image formation conditions, and An image forming apparatus as described in (6) or (7) above, wherein when an image is formed on a recording medium of a type outside the product specifications, if no jam occurs on the transported recording medium, the image forming conditions used when the image was formed are stored in the history data, and the stored image forming conditions are applied when subsequent images are formed on the same type of recording medium for the same print job.

[0021] (10) When image formation is performed on the recording medium of a type outside the product specifications in one print job, the image formation determination unit stores the type of the recording medium determined by the first determination unit as history data in a storage unit in association with jam occurrence information of the conveyed recording medium and image formation conditions, and When an image is formed on the recording medium of a type outside the product specifications, if no jam occurs on the conveyed recording medium, the image forming conditions at the time of the image formation are stored in the history data, and the stored image forming conditions are applied when an image is formed on the recording medium of the same type in the same print job thereafter, When an image is formed on a recording medium that is not of a type specified for the product, if a jam occurs on the conveyed recording medium, An image forming apparatus as described in (6) or (7) above, wherein, if the cumulative number of jam occurrences in the print job is less than a predetermined threshold, image forming conditions different from the image forming conditions when the image formation was performed are stored in the history data, and the stored image forming conditions are applied when forming images of the same type of recording medium in the same print job thereafter, and if the number of jam occurrences is equal to or greater than the predetermined threshold, the print job is canceled.

[0022] (11) Further comprising an operation display unit that receives setting inputs from a user and displays various information; When the type of the recording medium determined by the first determination unit is outside the product specifications, An image forming apparatus according to any one of (1) to (10) above, which displays on the operation display unit that the recording medium is outside the product specifications, and / or accepts permission from the user to perform printing using a recording medium outside the product specifications.

[0023] (12) A program for controlling an image forming apparatus including a conveying path, an image forming unit that forms an image on a recording medium conveyed in the conveying path, and a media sensor that is disposed on the conveying path upstream of the image forming unit in a conveying direction of the recording medium and that measures one or more paper physical properties of the conveyed recording medium, a step (a) of determining the type of the recording medium based on the paper physical properties measured by the media sensor; a step (b) of determining the conveyance performance of the recording medium conveyed through the conveyance path by a paper feed conveyance unit; a step (c) of determining whether or not to perform image formation based on the conveying performance determined in the step (b) when the type of the recording medium determined in the step (a) is outside the product specifications; A control program that causes a computer to execute a process including the above.

[0024] (13) In the step (c), if the type of the recording medium determined in the step (a) is outside the product specifications, the image formation by the image forming unit is stopped. The control program described in (12) above, wherein even if the recording medium is of a type outside the product specifications, if the conveying performance determined in step (b) satisfies a predetermined performance, image formation is performed on the recording medium of a type outside the product specifications without stopping image formation. [Effects of the Invention]

[0025] The image forming apparatus according to the present invention includes a first determination unit that determines the type of recording medium based on the paper physical properties measured by the media sensor, a second determination unit that determines the transport performance of the recording medium transported along the transport path, and an image formation determination unit that determines whether to form an image based on the transport performance determined by the second determination unit when the type of recording medium determined by the first determination unit is outside the product specifications. This allows automatic image formation according to the transport performance of the recording medium. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention; [Figure 2] FIG. 1 is a block diagram showing a configuration of an image forming apparatus. [Figure 3] FIG. 2 is a side view of the area around a media sensor disposed on a transport path inside the device. [Figure 4] FIG. 2 is a schematic diagram illustrating the configuration of a basis weight detection unit of a media sensor. [Figure 5] FIG. 2 is a cross-sectional view of a surface detection portion of the media sensor. [Figure 6] 4 is a flowchart showing a printing process in the first embodiment. [Figure 7] FIG. 10 is a schematic diagram for explaining a transport time as an example of an evaluation index for transport performance. [Figure 8] 10A and 10B are schematic diagrams for explaining torque margin as an example of an evaluation index for conveyance performance. [Figure 9] 10 is a table showing each evaluation index and a determination threshold value. [Figure 10] 10 is a control table showing the relationship between conveyance performance and image forming conditions. [Figure 11] 10 is an example of an operation screen displayed in step S125. [Figure 12] FIG. 10 is a diagram for explaining image forming conditions according to document type determination in the second embodiment. [Figure 13] 10 is a flowchart showing a printing process according to a third embodiment. [Figure 14] 10A and 10B are diagrams for explaining whether image formation is permitted or not in accordance with a jam occurrence history. [Figure 15] 10 is a flowchart showing a printing process in a fourth embodiment. [Figure 16] 10A and 10B are diagrams for explaining image forming conditions according to a jam occurrence history. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Note that identical elements in the drawings are designated by the same reference numerals, and redundant description will be omitted. The dimensional proportions in the drawings may be exaggerated for convenience of explanation and may differ from the actual proportions. In the drawings, the vertical direction is referred to as the Z direction, the front and rear directions of the image forming apparatus are referred to as the X direction, and the direction perpendicular to these X and Z directions is referred to as the Y direction. The X direction is also referred to as the width direction. In the vicinity of the media sensor (media sensor 18, described below), the recording medium transport direction, which is parallel to the plane of the transport path (transport path 143, described below) that is inclined relative to the horizontal plane and perpendicular to the X direction, is referred to as the Y' direction, and the direction perpendicular to this is referred to as the Z' direction (see Figures 3 and 4, etc.). The XY' plane is a plane parallel to the transport plane, and Z' is a direction perpendicular to this transport plane. In this embodiment, recording media include printing paper and various films. In particular, printing paper includes paper made using plant-derived mechanical pulp and / or chemical pulp. The types of recording media include gloss paper, matte paper, plain paper, high-gloss paper, coated paper, envelopes, etc. Hereinafter, recording media will also be simply referred to as "paper." In this embodiment, the types of paper (types of recording media) include not only paper classifications such as gloss paper, matte paper, plain paper, high-gloss paper, coated paper, envelopes, etc., but also basis weights (or basis weight categories).

[0028] Fig. 1 is a diagram showing a schematic configuration of an image forming apparatus 10 equipped with a media sensor 18 therein. Fig. 2 is a block diagram showing the configuration of the image forming apparatus 10. Fig. 3 is a side view showing the configuration of the media sensor 18 arranged on the conveying path 143.

[0029] (Image forming device 10) 1 and 2, an image forming apparatus 10 includes a control unit 11, a storage unit 12, an image forming unit 13, a paper feed and conveyance unit 14, an operation and display unit 15, a communication unit 16, a media sensor 18, etc. These are interconnected via signal lines such as a bus for exchanging signals.

[0030] (Control unit 11) The control unit 11 is made up of a CPU, ROM, RAM, etc., and executes various processes by executing programs stored in the ROM or in a storage unit 12 (described later), and controls each unit of the device and performs various arithmetic processing in accordance with the programs. The control unit 11 functions as a paper type determination unit 111, which is a first determination unit, a conveying performance determination unit 112, which is a second determination unit, and an image formation determination unit 113. These functions will be described later.

[0031] (Storage unit 12) The memory unit 12 includes an auxiliary memory such as a hard disk that stores various programs and data in advance. The memory unit 12 also stores product specifications for usable paper 90 and historical data related to paper transport. The memory unit 12 may also store a trained model and paper profile used to determine paper type. These trained models and paper profiles are used in the paper type determination process. Here, a "paper profile" is a pre-registered data set for a particular paper, which is associated with the measured values of the media sensor 18, characteristic data input by the user, paper size, and an arbitrary identification name (e.g., paper brand). The "paper type determination engine," also referred to as a trained model, is a trained model generated through supervised learning using training data, with the detection output of the media sensor 18 for the paper 90 as the input value and the paper type information set by the user for the paper 90 as the correct label. The training data may be data collected by a cloud server from multiple image forming devices connected to a network. The learning machine (not shown) can generate a trained model by a learning method using a neural network configured by combining perceptrons. The learning method is not limited to this, and various supervised learning methods can be used. For example, random forests, support vector machines (SVMs), boosting, Bayesian network linear discriminant analysis, nonlinear discriminant analysis, etc. can be applied. Furthermore, the learning machine can be a standalone high-performance computer using a CPU and a GPU (Graphics Processing Unit) processor, or a cloud computer.

[0032] (Image forming unit 13) Image forming unit 13 forms an image, for example, by electrophotography. As shown in FIG. 1, image forming unit 13 includes writing units 131 corresponding to the respective basic colors of Y (yellow), M (magenta), C (cyan), and K (black), photosensitive drums 132, and developing units 133 containing two-component developers each composed of toner and carrier for each color. Image forming unit 13 also includes an intermediate transfer belt 134, a secondary transfer unit 135, and a fixing unit 136. Toner images formed on photosensitive drums 132 by the developing units 133 for each color are superimposed on intermediate transfer belt 134 and transferred to paper 90 conveyed at a transfer position in secondary transfer unit 135, forming a full-color toner image. The toner image on paper 90 is fixed to paper 90 by applying heat and pressure in fixing unit 136 downstream. The fixing unit 136 includes a heater and a non-contact temperature sensor, and the power supply to the heater is controlled so that the temperature detected by the temperature sensor becomes a predetermined fixing control temperature.

[0033] (Paper feed conveyance section 14) Paper feed conveyance unit 14 feeds paper from each tray and conveys it to a conveyance path within the machine. Paper feed conveyance unit 14 includes multiple paper feed trays 141 on the main body side, a manual paper feed tray 142, and conveyance paths 143 and 144. Conveyance paths 143 and 144 include multiple paper detection sensors (only sensors s0 to s2 are shown as representatives) provided along these conveyance paths, conveyance rollers (roller pairs), and one or more drive motors (only drive motor M1 is shown as a representative) that drive these conveyance rollers.

[0034] The paper feed tray 141 (or paper feed tray 142) is equipped with a pickup roller (also called a feed roller) that feeds the topmost sheet of paper 90 stacked on an internal stacking tray, and sends the sheets 90 in the paper feed tray one by one to a downstream conveyance path. A media sensor 18 is disposed on the conveyance path 143 upstream of the image forming unit 13 (more specifically, the transfer position of the secondary transfer unit 135 (hereinafter simply referred to as the "image forming position")). As shown in FIG. 3, near the media sensor 18, the conveyance path 143 is formed between guides made of metal or the like that face each other at a predetermined distance. The guides include upper and lower guide plates 1431 and 1432 (see FIGS. 4 and 5). The physical properties of the paper 90 conveyed along the conveyance path 143 are measured by the media sensor 18.

[0035] When performing double-sided printing, in which an image is also formed on the back side of the paper 90, the paper 90 with an image formed on one side is conveyed to a conveyance path 144 for double-sided image formation located at the bottom of the device body. The paper 90 conveyed to this conveyance path 144 is turned over on a switchback path and then merges with a conveyance path 143 for single-sided printing, where an image is formed on the other side of the paper 90 again by the image forming unit 13. The paper 90 with the image formed is discharged onto a paper output tray 145 outside the device. Paper detection sensors s0 to s2 and the like arranged on the conveyance paths 143 and 144 inside the device detect the presence (or absence) of the paper 90 and send the detection result to the control unit 11. The control unit 11 detects a paper jam (hereinafter simply referred to as a "jam") in the paper 90 when the paper 90 does not reach or pass the detection position of the paper detection sensor at the predetermined timing.

[0036] Of the transport rollers provided along the transports 143 and 144, the transport roller provided immediately before the image formation position is specifically referred to as the registration roller r1. Paper 90 is fed from one of the paper feed trays and conveyed, temporarily hitting the registration roller r1 and stopping. Reaching the registration roller r1 is detected by a paper detection sensor s1 (also called a registration sensor). At this time, a loop (slack) is formed in the paper due to differences in the stopping timing of the transport rollers upstream of the registration roller r1, and the leading edge of the paper is aligned with the axial direction of the registration roller r1 for skew correction. Furthermore, paper 90 that has stopped after hitting the registration roller r1 is re-conveyed in synchronization with the image formation timing, and the leading edge timing is adjusted.

[0037] (Operation display section 15) The operation display unit 15 is equipped with a touch panel, numeric keypad, start button, stop button, etc., and displays the status of the image forming apparatus 10, and in manual setting mode is used for setting the type of paper placed in the paper feed tray 141, etc., and inputting instructions from the user. Also, when paper 90 (recording medium) outside the product specifications, which will be described later, is used, it displays that the recording medium is outside the product specifications and / or accepts permission from the user to perform printing using a recording medium outside the product specifications.

[0038] (Communications Department 16) The communication unit 16 communicates with other external devices such as an external PC terminal via a USB cable, a wired LAN (Local Area Network), a wireless LAN (for example, a LAN conforming to the IEEE802.11 standard), or the like.

[0039] (Media Sensor 18) 3, media sensor 18 is mainly composed of paper thickness detection unit 40, basis weight detection unit 50, and surface property detection unit 60, and measures multiple paper physical properties. Paper pressing mechanism 69 presses down on paper 90 when the surface property detection unit 60 detects the paper physical properties. The paper physical properties measured by media sensor 18 include paper thickness, basis weight, surface property, moisture content, etc., as described below.

[0040] Of the components of the media sensor 18, the paper thickness detection unit 40, the basis weight detection unit 50, and the surface property detection unit 60, the paper thickness detection unit 40 is disposed on the upstream side in the conveyance direction, and the basis weight detection unit 50 and the surface property detection unit 60 are disposed on the downstream side. The basis weight detection unit 50 and the surface property detection unit 60 are disposed side by side in the width direction (X direction) at the same position in the conveyance direction. For example, the basis weight detection unit 50 is disposed on the front side in the X direction, and the surface property detection unit 60 is disposed on the rear side. The main body of the surface property detection unit 60 is disposed above the conveyance path 143, and a paper pressing mechanism 69 is disposed below it, facing it. Along the conveyance path 143, conveyance rollers 41, 186, and 187 are disposed in this order from the upstream side.

[0041] (Paper thickness detection unit 40) In the paper thickness detection unit 40, the shaft position of the driven roller is displaced depending on the thickness of the paper 90 as the paper 90 is transported through the nip of the transport roller 41. The thickness of the paper 90 is measured by measuring the height of this displaced shaft. The transport rollers 41 are two rollers, the lower of which is a fixed (axial center fixed) drive roller, and the upper of which is a driven roller that is biased toward the drive roller so that it can move toward and away from the drive roller. The height of the upper roller is detected by a displacement sensor. The displacement sensor is composed of an actuator (detection lever) that contacts the shaft of the upper roller and an encoder that measures the amount of rotation of this actuator. The paper thickness detection unit 40 outputs, for example, paper thickness (microns) as a measurement result of the paper physical property (hereinafter also referred to as "paper thickness").

[0042] (Basis weight detection unit 50) 4 is a schematic diagram showing the configuration of the basis weight detection unit 50. The basis weight detection unit 50 is a transmission-type optical sensor that detects physical property values corresponding to the basis weight of the paper 90, and includes a light-emitting unit disposed below the conveyance path 143 and a light-receiving unit disposed above it, and measures the attenuation (transmittance) of light that passes through the paper 90. For example, the transmittance is output from the basis weight detection unit 50 as the measurement result of the paper physical property (hereinafter also simply referred to as "basis weight").

[0043] As shown in FIG. 4, the basis weight detection unit 50 includes multiple light-emitting units 51 and a single light-receiving unit 52. The light-emitting unit 51 includes a first light-emitting unit 51a, a second light-emitting unit 51b, and a third light-emitting unit 51c. The first, second, and third light-emitting units irradiate an irradiation area with first, second, and third irradiation light, respectively. This irradiation area (second irradiation area) is the inner area of the opening a12 when viewed from the Z' direction. The opening a12 is provided in the upper guide plate 1431. The lower guide plate 1432 also has an opening a22 at a position opposite the opening a12. The openings a11 and a12 have the same shape, e.g., a rectangle. Transparent sheets 54a and 54b made of PET or the like that transmit the wavelengths of the irradiation light are attached to the openings a12 and a22 to prevent foreign matter such as paper dust from the paper 90 passing through the conveyance path 143 from adhering to the openings a12 and a22. As described above, the opening a11 (see Figure 5) for the surface property detection unit 60 does not have any sheet attached, and when surface property detection is not being performed, an opening / closing shutter (not shown) closes the opening a11 to prevent foreign matter from adhering.

[0044] The first light-emitting unit 51a emits first irradiation light having a first wavelength. The first wavelength is, for example, a near-infrared wavelength that is longer than the wavelength of visible light. More specifically, the first wavelength includes, for example, a wavelength between 750 nm and 900 nm. The second light-emitting unit 51b emits second irradiation light having a second wavelength. The second wavelength is, for example, a wavelength of blue light included in visible light. More specifically, the second wavelength includes, for example, a wavelength between 400 nm and 470 nm. The first light-emitting unit 51a and the second light-emitting unit 51b are both arranged on the opposite side of the transport path 143 from the light-receiving unit 52, and the third light-emitting unit 51c is provided on the same side as the light-receiving unit 52 and in the vicinity of the light-receiving unit 52. The third light-emitting unit 51c emits third irradiation light having a third wavelength toward the irradiation area (opening a12). The third wavelength is, for example, the wavelength of green light in visible light. More specifically, the third wavelength includes, for example, a wavelength between 495 nm and 570 nm. The third wavelength is a wavelength different from the first wavelength (for example, a wavelength between 750 nm and 900 nm) and the second wavelength (for example, 400 nm to 470 nm).

[0045] The third irradiation light is irradiated toward the transport path 143 inside the upper and lower guide plates 1431 and 1432. A reflector 53 is provided inside the lower guide plate 1432, which is provided near the first light emitter 51a and the second light emitter 51b. The reflector 53 is painted, for example, in green, the same color as the third irradiation light, and reflects the third irradiation light. Note that the reflector 53 does not reflect the first irradiation light (near-infrared rays) and the second irradiation light (blue light rays), which are not the same color.

[0046] In this embodiment, the control unit 11 performs measurements both when the paper 90 is not present and when the paper 90 is present. During measurements when the paper 90 is not present, the control unit 11 controls the first light-emitting unit 51a and the second light-emitting unit 51b to emit the first irradiation light and the second irradiation light at different times. The light-receiving unit 52 receives the first irradiation light and the second irradiation light, detects the light intensity of each irradiation light, and outputs the detected light intensity of the first irradiation light and the second irradiation light to the control unit 11. Similarly, during measurements when the paper 90 is present, the control unit 11 irradiates the paper 90 transported to the position of the opening a12 with the first irradiation light and the second irradiation light. The light-receiving unit 52 receives the transmitted light (first transmitted light, second transmitted light) of the first irradiation light and the second irradiation light, detects the light intensity of each irradiation light, and outputs the detected light intensity of the first transmitted light and the second transmitted light to the control unit 11. That is, the light receiving section 52 detects the first irradiated light and the second irradiated light when the paper 90 is not present, and the first transmitted light and the second transmitted light when the paper 90 is present in the opening a12.

[0047] Similarly, with respect to the third light-emitting unit 51c, the light-receiving unit 52 detects the first reflected light reflected by the reflecting unit 53 when no paper 90 is present, and the second reflected light reflected by the surface of the paper 90 when the paper 90 is in the opening a12.

[0048] The control unit 11 calculates a first transmittance by dividing the amount of the first transmitted light by the amount of the first irradiated light. Similarly, the control unit 11 calculates a second transmittance by dividing the amount of the second transmitted light by the amount of the second irradiated light. The type of paper 90 is then determined based on the first and second transmittances and the determination criteria stored in the memory unit 12.

[0049] (Surface property detection unit 60) FIG. 5 is a cross-sectional view of the surface property detection unit 60. The surface property detection unit 60 includes a housing 61, a light-emitting unit 62, a collimating lens 63, and multiple light-receiving units 64 (641, 642). As described below, the unit optically detects specularly reflected light and diffusely reflected light from the paper surface. An opening a11 (measurement area / irradiation area) is provided in the upper guide plate 1431, and this opening a11 is the area illuminated by the light-emitting unit. The intersection p1 shown in the figure is approximately the center of the irradiation area. The paper 90 transported to the opening a11 is temporarily stopped. In this state, the paper 90 is pressed from below by a paper pressing mechanism 69, positioning it. The reference plane within the opening a11 is a virtual plane including the lower surface of the upper guide plate 1431. During measurement, the surface of the positioned paper 90, which is the object to be measured, is placed on the reference plane. The light emitted from the light-emitting unit is collimated by a collimating lens and irradiated at an incident angle of 75° with respect to the reference plane. The wavelength of the irradiated light is, for example, 465 nm. The multiple light receiving units 64 receive specularly reflected light and diffusely reflected light. For example, they may be arranged at three locations with reflection angles of 30 degrees (for diffusely reflected light), 60 degrees (for diffusely reflected light), and 75 degrees (for specular reflected light), or at two locations with reflection angles of 60 degrees and 75 degrees. The surface property detection unit 60 outputs signals from these light receiving units as measurement results of the paper physical properties (hereinafter also referred to as "surface property 1").

[0050] (Paper pressing mechanism 69) This paper pressing mechanism 69 is disposed below the lower guide plate 1432. The paper pressing mechanism 69 includes a pressing unit 691. The paper pressing mechanism 69 also includes a drive motor, a cam mechanism, etc. (none of which are shown). The upper surface of the pressing unit 691 is a plane parallel to the lower guide plate 1432 that moves up and down when driven by the drive motor. During normal paper passage, the pressing unit 691 is approximately flush with the lower guide plate 1432, but during measurement, it rises and presses the paper 90 against the upper main body side of the surface property detection unit 60. When pressed, transport of the paper 90 stops.

[0051] (Other outputs of Media Sensor 18) As described above, the paper thickness detection unit 40, basis weight detection unit 50, and surface property detection unit 60 output paper thickness, basis weight, and surface property 1 as paper physical properties, respectively. However, the media sensor 18 may include other sensors that output other paper physical properties. For example, the media sensor 18 may include sensors that output "surface property 2," "moisture content," and "paper thickness (multiple feed)" as paper physical properties. "Surface property 2" provides an index related to the depth of the paper 90. Specifically, light is irradiated onto the surface of the paper 90 at a large incident angle (80 degrees or more but less than 90 degrees), the state is photographed, and the resulting image data is processed to output an index related to the depth corresponding to the surface irregularities as a measurement result. "Moisture content" can be measured, for example, using a moisture content sensor that optically detects the amount of light absorbed by OH groups using a near-infrared method. This moisture content meter irradiates light of a predetermined wavelength in the near-infrared region onto the paper 90, utilizing the property that the light absorption rate changes depending on the moisture content of the paper 90. The moisture content meter outputs, for example, the moisture content as a measurement result of the paper's physical properties. Paper thickness (multi-feed) is measured using an ultrasonic sensor. The ultrasonic sensor has a transmitter and a receiver, which are arranged across the conveying path 143. The ultrasonic waves emitted from the transmitter pass through the paper 90 and are received by the receiver. The degree of decrease in the signal received by the receiver detects the thickness of the paper, i.e., whether or not a multi-feed, in which two or more sheets of paper are conveyed overlapping each other, is detected. The detection output of the ultrasonic sensor can be used to determine whether or not the paper is an envelope.

[0052] (Paper type determination process) The paper type determination unit 111 determines the paper type based on the paper physical properties detected by the media sensor 18. Specifically, the paper type determination unit 111 transports the paper 90 to be measured along the transport path 143 and acquires detection data from the paper thickness detection unit 40, the basis weight detection unit 50, and the surface property detection unit 60 of the media sensor 18. Hereinafter, the data detected by the paper thickness detection unit 40 will be referred to as measurement value 1, the data detected by the basis weight detection unit 50 will be referred to as measurement value 2, and the data detected by the surface property detection unit 60 will be referred to as measurement value 3. The paper type determination unit 111 determines the paper type (paper classification) and the basis weight classification using the acquired measurement values 1 to 3 (or their average data) and a trained model (paper type discrimination engine). Alternatively, the paper type determination unit 111 determines the paper type (paper classification) and the basis weight classification using the acquired measurement values 1, 2, and 3 (or their average data) and a paper profile. Examples of paper type determinations are gloss paper, matte paper, plain paper, high-gloss paper, coated paper, and envelopes. Examples of basis weight classifications are the following 12 classifications. Note that the following classifications are examples, and classifications may be made using different classifications. Note that in the following, when the paper classification is coated paper or envelope in the main body paper feed tray 141 other than the manual feed tray 142, the paper is outside the product specifications. Furthermore, paper whose paper type (basis weight classification) is determined to be classifications 11 and 12 is outside the product specifications. (Category 1)~61g / m 2 , (Category 2) 62~75 g / m 2 , (Category 3) 76~81 g / m 2 , (Category 4) 82~92 g / m 2 , (Category 5)93~106 g / m 2 , (Category 6) 107~136 g / m 2 , (Category 7) 137~177 g / m 2 , (Category 8) 178~217 g / m 2 , (Category 9)218~257 g / m 2 , (Category 10) 258~301 g / m 2 , (Category 11) 302~351 g / m 2 , (Category 12) 352 g / m 2 ~.

[0053] (Printing process in the first embodiment) FIG. 6 is a flowchart showing the printing process in the first embodiment, and this printing process is mainly executed by the control unit 11 of the image forming apparatus 10.

[0054] (Step S101) The image forming apparatus 10 starts executing the accepted print job. If the automatic media setting mode is enabled (YES), the control unit 11 proceeds to step S103. On the other hand, if the manual setting mode is enabled (NO), the control unit 11 proceeds to step S102.

[0055] (Step S102) After accepting the paper type setting input by the user via the operation display unit 15, the image forming conditions are set to correspond to the set paper type, and printing is performed by normal printing processing, and then the process is completed (END).

[0056] (Step S103) The control unit 11 controls the paper feed and transport unit 14 to feed and transport the paper 90 from the paper feed tray 141. At this time, because the automatic setting mode is selected, the transport speed is slower than the normal (image forming) transport speed for plain paper (for example, 250 mm / sec, hereinafter also referred to as "standard speed vs."). Then, the media sensor 18 measures the paper properties of the paper 90.

[0057] (Step S104) The paper type determination unit 111 performs the above-described paper type determination process based on the paper physical properties (measured values 1 to 3) obtained in step S103.

[0058] (Step S105) If the result of the determination in step S104 is that the paper type is out of the product specifications (YES), the control unit 11 determines that the paper is out of the product specifications (for example, the paper weight is in category 11 (350 g / m 2 If the paper is coated paper, or an envelope, the process proceeds to step S121. On the other hand, if the paper is within the product specifications (NO), the process proceeds to step S106.

[0059] (Step S106) Here, the image forming conditions corresponding to the automatically set paper type are set for the paper 90 within the product specifications, and printing is performed by normal printing processing and then terminated.

[0060] (Step S121) The conveying performance determination unit 112 evaluates the conveying performance of the paper 90. As evaluation indexes for conveying performance, conveying time and driving torque (torque margin) can be used as shown below. FIG. 7 is a schematic diagram for explaining conveying time tx as an example of an evaluation index for conveying performance. FIG. 8 is a schematic diagram for explaining torque margin as an example of an evaluation index for conveying performance. FIG. 9 is a table showing evaluation indexes and determination thresholds.

[0061] (Evaluation of transport performance based on transport time tx) As described below, the conveying time tx may be used as an evaluation index for conveying performance. As shown in FIG. 7, a drive motor M1 drives each conveying roller of the conveying path 143, including the registration roller r1, as well as the pickup roller r41, the paper feed roller r42, and the separation roller r43 of the paper feed tray 141. The drive transmission of the drive motor M1 to the pickup roller r41, the paper feed roller r42, and the separation roller r43 is turned on and off by a clutch CL1. The pickup roller r41 and the separation roller r43 rotate in the same direction (counterclockwise in the figure) (i.e., the outer circumferential surfaces of the two rollers move in opposite directions at their contact points). The paper feed roller r42 applies a forward conveying force to the paper 90, i.e., a conveying force that moves the paper 90 to the right in the figure. Meanwhile, the separation roller r43 applies a reverse conveying force to the paper 90. A torque limiter provided in the drive system of the separating roller r43 is set so that the conveying force of the paper feed roller r42 is stronger than the conveying force of the separating roller r43. As a result, the topmost sheet of paper 90 is given a conveying force in the forward direction (to the right), and the second and subsequent sheets of paper 90 are given a conveying force in the reverse direction, preventing double feeding (the conveying of two or more sheets).

[0062] The conveying performance is determined based on whether the delay time td of the paper 90 being used is within a predetermined value x1, which is a judgment threshold, or exceeds the predetermined value x1, as shown in Figure 9. The delay time td is calculated by subtracting a preset standard time ts from the conveying time tx (delay time td = tx - ts).

[0063] The standard time ts is the time from when the control signal ON (t00) is output to the drive motor M1 of the paper feed tray 141 until the paper 90 to be evaluated actually reaches the detection position (t03) of the paper detection sensor sx. This paper detection sensor sx is a paper detection sensor arranged at a predetermined position on the conveyance path 143 between the paper feed tray 141 (or paper feed tray 142) on which the target paper 90 is placed and the image forming position. For example, the paper detection sensor sx referred to here may be either the paper detection sensor s0 or s1 shown in FIG. 1.

[0064] Standard time ts = standard time t1 + standard time t2 + standard time t4. Standard time t1 is calculated from the start request for drive motor M1, the ON request time for paper feed clutch CL1, the start time of drive motor M1, the engagement time of clutch CL1, and the control cycle. Standard time t2 is the time from engagement of paper feed clutch CL1 to arrival at paper feed roller r42. It is calculated from the conveyance speed of pickup roller r41 and the distance between pickup roller r41 and paper feed roller r42 (nip). Standard time t3 is the time from arrival at paper feed roller r42 to arrival at paper detection sensor sx. It is calculated from the conveyance speed of paper feed roller r42 (and the conveyance rollers in conveyance path 143) and the path length from paper feed roller r42 to paper detection sensor sx on conveyance path 143.

[0065] Paper outside the product specifications (e.g., 350 g / m 2 In the case of thick paper (when using thick paper), slippage is likely to occur when the paper is picked up by the pickup roller r41 or when it is transported by the paper feed roller r42 and the transport rollers on the transport path 143. When slippage occurs, a delay occurs during a period corresponding to standard times t2 and t3, and the actual transport time is longer than standard times t2 and t3. If paper transport takes longer than the expected standard time, problems such as misalignment of the image leading edge or jamming can occur. The risk of these problems occurring is determined from the delay time td. That is, as shown in FIG. 9, if the delay time td is within a predetermined value x1, the transport performance determination unit 112 determines that the target paper 90 satisfies a certain level of transport performance and that the risk of a problem occurring is low. However, if the delay time td exceeds the predetermined value x1, the transport performance determination unit 112 determines that the target paper 90 does not satisfy the transport performance and that the risk of a problem occurring is high.

[0066] (Evaluation of transport performance based on driving torque Tx) Furthermore, the drive torque Tx of the drive motor M1 may be used as an evaluation index for conveyance performance, as explained below. The drive torque Tx of the drive motor M1 can be detected by a torque detection unit (see Figure 1). The torque detection unit is a driver current detection circuit located on the printer control board, and is composed of a shutoff resistor, a voltage dividing resistor, a differential amplifier, a filter circuit, etc. The torque detection unit calculates the drive torque Tx from the power supply voltage current flowing into the motor driver that controls the operation of the drive motor M1.

[0067] As shown in FIG. 9, the conveying performance is determined based on whether the torque margin Tm during conveyance of the paper 90 is equal to or greater than a predetermined value y1, which is a determination threshold, or whether it is less than the predetermined value y1. The torque margin Tm is calculated by subtracting the maximum torque Tx during conveyance in the determination section from the torque limit value Tl (torque margin Tm = Tl - Tx). Here, the determination section is any section from the start of feeding the target paper 90 to the detection by the paper detection sensor s1 (registration sensor) upstream of the image formation position. For example, the determination may be based on the torque Tx in the section corresponding to the conveyance time tx in FIG. 7 as the entire section, or on the torque tx in a shorter section, such as the section from t00 to t02 or the section from t00 to the time when the paper detection sensor s0 detects the paper 90. Alternatively, the determination section may be the section from t0 until a predetermined time has elapsed.

[0068] Paper outside the product specifications (e.g., 350 g / m 2 When using thick paper (such as cardboard), the drive torque required to pick up and transport the paper increases. If the drive torque (load) exceeds the torque limit value Tl specified for the drive motor M1, the motor will lose synchronization, causing problems such as jamming. The risk of these problems occurring is determined based on the torque margin Tm. As shown in Figure 9, if the torque margin Tm is equal to or greater than a predetermined value y1, the transport performance determination unit 112 determines that the target paper 90 satisfies a certain level of transport performance and that there is a low risk of a problem occurring. If the torque margin Tm is less than the predetermined value y1, the transport performance determination unit 112 determines that the target paper 90 does not satisfy the transport performance and that there is a high risk of a problem occurring.

[0069] (Step S122) 7 to 9, the image formation determination unit 113 determines whether the conveyance performance of the target paper 90 based on the conveyance time tx or the drive torque tx satisfies a predetermined performance, and if the predetermined performance is satisfied (YES), the process proceeds to step S124 to stop image formation. On the other hand, if the predetermined performance is not satisfied (NO), the process proceeds to step S123.

[0070] (Step S123) The image formation determination unit 113 performs a process to cancel the print job (image formation). Specifically, the operation display unit 15 displays a message that the print job has been canceled because the paper 90 does not meet the product specifications. In addition, one of the following two post-processing steps is performed accordingly. Post-processing 1: This is a so-called purge process, in which the image forming unit 13 does not form an image on the paper 90 being conveyed, and the paper is discharged blank onto a discharge tray 145 outside the apparatus via a conveyance path 143 . Post-processing 2: Jam detection processing. If the conveying performance results in a worse result (for example, if it exceeds a predetermined threshold x2 that is larger than the predetermined threshold x1), the paper is immediately stopped at a predetermined position on the conveying path 143, or is stopped just before the registration roller r1 and is not conveyed again, and a jam is detected. Then, the jammed state is displayed on the operation display unit 15, and the user is prompted to manually remove the target paper 90.

[0071] (Step S124) The image formation determination unit 113 sets image formation conditions according to the conveyance performance evaluated in step S121. Specifically, the image formation determination unit 113 sets image formation conditions according to the conveyance time tx or the drive torque Tx. These image formation conditions may be calculated using a predetermined linear calculation formula according to the value of the conveyance time tx or the drive torque Tx, or may be set in multiple stages according to the range of values (see FIG. 10 described later). Examples of image formation conditions include the conveyance speed of the paper 90 and the fixing control temperature of the fixing unit 136. Furthermore, the set current of the drive motor M1 may be changed according to the drive torque Tx.

[0072] Figure 10 is a control table showing the relationship between conveyance performance and image formation conditions. This control table is stored in the storage unit 12 in advance. In Figure 10, the evaluated delay time td (conveyance time tx), the conveyance speed set according to the value, and the relationship with the fixing control temperature are shown. For example, if the delay time td is below a predetermined threshold value x0 (where x0 < x1), the image formation determination unit 113 sets the conveyance speed to 0.5 times the standard speed vs, and sets the fixing control temperature to a high temperature 1 higher than the normal temperature (for plain paper).

[0073] (Step S125) The control unit 11 causes the operation display unit 15 to display that it is in the non-standard paper output mode. Figure 11 is an example of the operation screen 152 displayed on the operation display unit 15 when using non-standard paper. At the time of this display, it may be possible to accept permission from the user to execute printing using the non-standard paper 90 as shown on the operation screen 152. The user gives permission to execute by operating the execute button on the operation screen 152. On the other hand, by operating the cancel button on the operation screen 152, the user can cancel the print job.

[0074] (Step S126) The control unit 11 performs image formation on the target paper 90 under the image formation conditions set in step S124. For the second and subsequent sheets of paper 90 in the same print job (using the same paper), the processing from step S103 and below may be repeated, or the processing from step S103 to S125 may be skipped, and only step S126 may be repeated to perform image formation up to the last sheet under the same image formation conditions.

[0075] As described above, the image forming apparatus 10 according to the first embodiment includes an image formation determination unit 113 that determines whether to form an image based on the conveying performance determined by the second determination unit (conveying performance determination unit 112) when the type of recording medium determined by the first determination unit (paper type determination unit 111) based on the paper physical properties measured by the media sensor is outside the product specifications. This allows automatic determination of whether to form an image based on the conveying performance, even when a recording medium outside the product specifications is used. Furthermore, when image formation is to be performed on a recording medium outside the product specifications, the image formation determination unit 113 of the image forming apparatus 10 performs image formation under image formation conditions set according to the determined conveying performance. This allows appropriate paper conveying conditions and image formation conditions to be automatically set, even when paper outside the product specifications is used.

[0076] (Second embodiment) In the first embodiment, the image forming conditions are set according to the conveying performance, but in the second embodiment described below, the image forming conditions are set according to the document type in addition to this.

[0077] Fig. 12 is a diagram for explaining image formation conditions according to document type determination in the second embodiment. Fig. 12 shows a control table, etc., used in setting image formation conditions in step S124 of Fig. 6, instead of the control table of Fig. 10. In the second embodiment, the configuration other than that shown in the figure is the same as that of the first embodiment, and therefore description thereof will be omitted.

[0078] Figure 12(a) is a control table showing the relationship between the transport performance, document type, and image formation conditions. Note that Figure 12(a) shows the case of paper within the specification range for reference. When paper is within the specification range, image formation is performed under normal image formation conditions.

[0079] As shown in FIG. 12(a), when the conveying performance is unsatisfactory (step S122: NO in FIG. 6), the image formation determination unit 113 does not permit image formation and therefore does not set image formation conditions. On the other hand, when the conveying performance is satisfactory (step S122: YES in FIG. 6), the image formation determination unit 113 sets the image formation conditions to condition 1 or condition 2 depending on the document type. The document types are classified according to the table shown in FIG. 12(b). Conditions 1 and 2 of the image formation conditions to be set are determined by referring to the table shown in FIG. 12(c).

[0080] As shown in FIG. 12(b), the image formation determination unit 113 analyzes the document type based on the full-color or monochrome color mode setting for the print job to be executed and the graphic or text image information included in the print data of the print job. For example, the image formation determination unit 113 performs image analysis of the print data to determine whether the document contains graphics or is composed of text data only. This determination may be based solely on the color mode, or solely on the image, or on a combination of both. In the latter case, if one of the elements is full-color or graphic, the document may be determined as Type 1, and if both elements are monochrome or text, the document may be determined as Type 2.

[0081] 12(c), the image formation determination unit 113 sets the image formation conditions in the order of conditions 1, 2, and 3 so as to provide greater margins in conveying performance and image quality (fixing performance) (hereinafter also referred to as looser image formation conditions). For example, in condition 2, the conveying speed is set to low speed 2, which is slower than low speed 1. For example, low speeds 1, 2, and 3 are 0.7 times, 0.5 times, and 0.3 times the standard speed, respectively.

[0082] In this way, in the image forming apparatus 10 according to the second embodiment, the image formation determination unit 113 sets the image formation conditions according to the determined document type as well as the conveying performance. This provides the same effects as in the first embodiment, and furthermore, in the second embodiment, more appropriate image formation conditions can be set.

[0083] (Third embodiment) Next, an image forming apparatus 10 according to a third embodiment will be described with reference to Figures 13 and 14. In the third embodiment, information on jam occurrence is used as history data, and whether image formation is possible is determined according to the occurrence history.

[0084] Fig. 13 is a flowchart showing printing processing in the third embodiment. Fig. 14 is a diagram for explaining the determination of whether image formation is permitted or not in accordance with the jam occurrence history, with Fig. 14(a) showing the history data and Fig. 14(b) showing a determination table used to determine the number of jam occurrences and whether image formation is permitted or not.

[0085] (Steps S201 to S206) The control unit 11 (or the paper type determination unit 111) executes the processes of steps S201 to S206, and executes printing processes according to the set mode or the determined paper type. These processes directly correspond to steps S101 to S106 in Fig. 6, and therefore a description thereof will be omitted.

[0086] (Step S211) If it is determined in step S205 that the paper type is outside the product specifications, the image formation determination unit 113 refers to the history data in the storage unit 12 to check whether data relating to the same type of paper 90 has been accumulated. As shown in FIG. 14(a), for example, if the type of paper determined in step S204 is the outside product specifications paper type 01 with the same classification and basis weight, the image formation determination unit 113 determines that history data exists (YES) and proceeds to step S212. On the other hand, if there is no history data of the same type (if it is a new paper type), the image formation determination unit 113 proceeds to step S213. Proceed to S221.

[0087] (Step S212) The image formation determination unit 113 references the number of jam occurrences from the history data for the same paper type, compares this with the determination table in FIG. 14(b), and determines whether image formation is permitted or prohibited. If the number of jam occurrences in the history data is less than the predetermined threshold N1, it is permitted, that is, the paper is outputtable (YES), and the process proceeds to step S221, and in subsequent processes, it is determined whether image formation is to be performed based on the conveying performance. On the other hand, if the number of jam occurrences is equal to or greater than the predetermined threshold N1, it is not permitted, that is, the paper is not outputtable (NO), and the process proceeds to step S223. Then, the image formation determination unit 113 stops image formation regardless of the determination result of the conveying performance evaluation.

[0088] (Steps S221 to S226) The control unit 11 (or the conveying performance determination unit 112, or the image formation determination unit 113) executes the processes of steps S221 to S226, determines whether image formation is possible based on the determined conveying performance, and stops image formation or executes image formation under image formation conditions according to the conveying performance. These processes directly correspond to steps S121 to S126 in FIG. 6, and therefore, description thereof will be omitted.

[0089] (Step S231) If a jam occurs during image formation on the paper 90 (YES), the control unit 11 proceeds to step S232. On the other hand, if a jam does not occur (NO) and image formation is completed normally, the control unit 11 skips step S232 and ends the process.

[0090] (Step S232) The control unit 11 records jam occurrence information in the history data. If it is a new type of paper, new history data is generated. If it is an existing type, the number of occurrences is incremented. Note that if the increment causes the number of occurrences to exceed the predetermined threshold N1, subsequent uses of this paper 90 will be deemed unauthorized by the processing of steps S211-S212.

[0091] In this way, in the image forming apparatus 10 according to the third embodiment, if the jam occurrence history in the history data is equal to or less than a predetermined threshold, image formation is performed based on the conveying performance determined by the second determination unit, and if the jam occurrence history exceeds the predetermined threshold, image formation is stopped regardless of the determination result of the second determination unit. This makes it possible to prevent repeated jam occurrences.

[0092] (Fourth embodiment) Next, an image forming apparatus 10 according to a fourth embodiment will be described with reference to Figures 15 and 16. In the fourth embodiment, jam occurrence information is used as history data, and image formation conditions or non-permission information is set according to the occurrence history.

[0093] FIG. 15 is a flowchart showing printing processing in the fourth embodiment. This differs from the flowchart in FIG. 13 for the third embodiment described above in steps S512-S513 and steps S541-S546. FIG. 16 is a diagram illustrating the image formation conditions and non-permission information set according to the jam occurrence history. FIG. 16(a) shows a table indicating the history data for each paper type and the set image formation conditions or non-permission information, and FIG. 16(b) shows a table indicating the relationship between the number of jam occurrences and the set image formation conditions or non-permission information. As shown in FIG. 16(b), as the number of jam occurrences increases, the image formation conditions become more lenient on the device side, from Condition 1 to Condition 2 to Condition 3. That is, as the condition increases from Condition 1 to Condition 2 to Condition 3, the conveyance speed is slowed and the fixing control temperature is set higher, thereby increasing the margin for the device's conveyance capacity and fixing capacity. This allows for a margin in conveyance performance and image quality (fixing performance). Note that these conditions 1, 2, and 3 are the same as those shown in Fig. 12(c). Also, if the number of jam occurrences exceeds a predetermined threshold N1, non-permission information is set. The history data in Fig. 16(a) shows each paper type and the number of jam occurrences, which are set by the processing of steps S541 to S547 in Fig. 16 described below, and the image formation conditions or non-permission information set according to the number of occurrences.

[0094] (Steps S501 to S506) The control unit 11 (or the paper type determination unit 111) executes the processes of steps S501 to S506, and executes printing processes according to the set mode or the determined paper type. These processes directly correspond to steps S201 to S206 in Fig. 13 (or steps S101 to S106 in Fig. 6), and therefore a description thereof will be omitted.

[0095] (Step S511) In step S511, the image formation determination unit 113 performs processing similar to S211 in Figure 13, by referring to the historical data in the memory unit 12 as shown in Figure 16(a) and checking whether data related to the same type of paper 90 has been accumulated.

[0096] (Step S512) If the same type of data is stored (S511: YES) and the image formation conditions of the history data are set to "not permitted" due to a jam occurrence history of more than the predetermined threshold N1 (S512: NO), the process proceeds to step S523, and the print job is stopped. On the other hand, if the paper is an outputtable paper (YES), that is, if the image formation conditions of the history data are not set to "not permitted" (S512: YES), the image formation determination unit 113 proceeds to step S513.

[0097] (Step S513) The image formation determination unit 113 sets the image formation conditions read from the history data. For example, in the example of Fig. 16(a), if the paper type is out of product specifications 01, condition 1 (the image formation condition applied to the immediately preceding paper) is set as the image formation condition. After that, the process proceeds to step S526, where image formation is performed on the out-of-product specifications paper using the image formation conditions set in step S513.

[0098] (Steps S521 to S526) The control unit 11 (or the conveying performance determination unit 112, or the image formation determination unit 113) executes the same processing as steps S221 to S226 in Fig. 13 (or steps S121 to S126 in Fig. 6). That is, the control unit 11 determines whether or not image formation is possible based on the determined conveying performance, and executes image formation under image formation conditions according to the conveying performance set in step S524 or image formation conditions based on the history data set in step S513.

[0099] (Step S541) 13, and if a jam occurs during image formation on the paper 90 (YES), the controller 11 increments the number of jam occurrences in the history data and proceeds to step S544. On the other hand, if a jam does not occur (NO) and image formation is completed normally, the controller 11 proceeds to step S542.

[0100] (Step S542) The image formation determination unit 113 records the current image formation conditions (used in step S526) in the history data of the determined paper type. These recorded image formation conditions are read out in step S513 when forming an image on the next paper 90 (using the same paper type for the same print job) and are used for image formation.

[0101] (Step S543) If the print job has not ended (NO), the control unit 11 returns the process to step S503 and repeats the subsequent processes. On the other hand, if the print job has ended (YES), the process ends.

[0102] (Step S544) The image formation determination unit 113 determines whether the number of jams in the history data is greater than a predetermined threshold N1, and if so (YES), proceeds to step S545, and if less than the predetermined threshold N1 (NO), proceeds to step S547.

[0103] (Steps S545 and S546) Here, the image formation determination unit 113 records non-permission in the history data, and performs the same print job cancellation process as in step S123 of FIG. 6, and then ends the process (END).

[0104] (Step S547) Here, as the number of jams increases, the image formation determination unit 113 records image formation conditions different from the current image formation conditions (used in step S526) in the history data for the determined paper type. Specifically, the image formation conditions are changed to conditions that are one level looser according to the table in FIG. 16(b). Thereafter, the process returns to step S503, and the subsequent processes are repeated. In this case, the image formation conditions in the history data read in step S513 are applied to image formation on the next paper 90 of the same print job. These image formation conditions are the image formation conditions recorded in step S547. Note that in the fourth embodiment, the history data is reset each time a print job ends so that it is applied only within the same print job (for example, a reset process is performed after step S543 (NO)). However, the history data may be continuously used without being reset so that it is applied across print jobs.

[0105] In this way, in the image forming apparatus according to the fourth embodiment, when an image is formed on a recording medium outside the product specifications and no jam occurs, the image forming conditions used when the image was formed are stored in the history data, and the stored image forming conditions are applied when subsequent images are formed on the same type of recording medium in the same print job. When an image is formed on a recording medium outside the product specifications and a jam occurs on the conveyed recording medium, if the cumulative number of jams in the print job is less than a predetermined threshold, image forming conditions different from those used when the image was formed are stored in the history data, and the stored image forming conditions are applied when subsequent images are formed on the same type of recording medium in the same print job. If the cumulative number of jams is equal to or greater than the predetermined threshold, the print job is canceled. This achieves the same effects as the third embodiment, and, when a jam occurs, different image forming conditions, i.e., different paper conveyance conditions, can be set to prevent jams.

[0106] The configuration of the image forming apparatus 10 described above is a description of the main configuration in explaining the features of the above-described embodiments. However, the configuration is not limited to the above-described configuration and can be modified in various ways within the scope of the claims. Furthermore, configurations that are included in general image forming apparatuses 10 are not excluded. Furthermore, the processing in the image forming apparatus 10 according to each of the above-described embodiments may include steps other than those shown in the flowcharts above, or may not include some of the steps described above. Furthermore, the order of the steps is not limited to the above-described embodiments. Furthermore, each step may be combined with other steps and executed as a single step, may be executed as part of other steps, or may be divided into multiple steps and executed.

[0107] (Variation) As a modified example, when image forming apparatus 10 forms an image on a recording medium outside the product specifications and no jam occurs on the conveyed recording medium, it may store the image forming conditions used when the image was formed in the history data, and apply the stored image forming conditions to subsequent image formations on the same type of recording medium in the same print job. Specifically, in the fourth embodiment, the image forming conditions were applied to the image forming conditions for the next sheet of paper within the same print job (steps S542 to S511 and S512 in FIG. 15). However, the history data may not be reset even after the print job is completed, and the same image forming conditions recorded in the history data may be applied to subsequent print jobs for the same type of paper. This allows stable image formation while reducing the risk of jamming, even when using paper outside the product specifications.

[0108] The means and methods for performing various processes in the image forming apparatus 10 according to the above-described embodiment can be realized by either a dedicated hardware circuit or a programmed computer. The program may be provided by a computer-readable recording medium such as a USB memory or a DVD (Digital Versatile Disc)-ROM, or may be provided online via a network such as the Internet. In this case, the program recorded on the computer-readable recording medium is typically transferred to and stored in a storage unit such as a hard disk. The program may be provided as standalone application software or may be incorporated into the software of the device as a function of the device. [Explanation of symbols]

[0109] 10 Image forming device 11 Control section 111 Paper type determination unit (first determination unit) 112 Conveyance performance determination unit (second determination unit) 113 Image formation determination unit 12 Storage section 13 Image forming unit 14 Paper feed transport section 15 Operation panel 16 Communications Department 18 Media Sensor 40 Paper thickness detection unit 50 Basis weight detection unit 60 Surface detection unit 69 Paper pressing mechanism

Claims

1. a paper feed and conveyance unit that feeds and conveys a recording medium to a conveyance path; an image forming unit that forms an image on the recording medium conveyed through the conveyance path; a media sensor disposed on the conveying path upstream of the image forming unit in a conveying direction of the recording medium, the media sensor measuring one or more paper physical properties of the conveyed recording medium; a first determination unit that determines the type of the recording medium based on the paper physical properties measured by the media sensor; a second determination unit that determines the transport performance of the recording medium transported through the transport path; an image formation determination unit that determines whether or not to perform image formation based on the conveying performance determined by the second determination unit when the type of the recording medium determined by the first determination unit is outside of product specifications; Equipped with The type outside the product specifications is a case where the basis weight category determined by the first determination unit is a category of a predetermined basis weight or more, the second determination unit determines whether or not conveyance performance satisfies a predetermined performance from a detection result of a drive torque of a drive motor of the paper feed conveyance unit in any section from when the paper feed conveyance unit starts feeding the recording medium to when the recording medium reaches a detection position of a paper detection sensor disposed at a predetermined position upstream of an image forming position of the image forming unit in the conveyance path; Image forming device.

2. When the image formation determination unit stops image formation because the recording medium is a type outside the product specifications, the image formation determination unit executes a purge process in which the recording medium being conveyed is discharged blank outside the apparatus, or a jam detection process in which the recording medium is stopped midway along the conveyance path, An image forming apparatus as described in claim 1, wherein when image formation is performed even if the recording medium is a type outside the product specifications, the conveying speed and / or fixing control temperature of the recording medium are set as image formation conditions during image formation according to the determined conveying performance, and the image formation is performed under the set image formation conditions.

3. a paper feed and conveyance unit that feeds and conveys a recording medium to a conveyance path; an image forming unit that forms an image on the recording medium conveyed through the conveyance path; a media sensor disposed on the conveying path upstream of the image forming unit in a conveying direction of the recording medium, the media sensor measuring one or more paper physical properties of the conveyed recording medium; a first determination unit that determines the type of the recording medium based on the paper physical properties measured by the media sensor; a second determination unit that determines the transport performance of the recording medium transported through the transport path; an image formation determination unit that determines whether or not to perform image formation based on the conveying performance determined by the second determination unit when the type of the recording medium determined by the first determination unit is outside of product specifications; Equipped with The type outside the product specifications is a case where the basis weight category determined by the first determination unit is a category of a predetermined basis weight or more, the second determination unit determines whether or not the conveyance performance satisfies a predetermined performance in accordance with a conveyance time tx from when the paper feed conveyance unit starts feeding the recording medium until when the recording medium reaches a detection position of a paper detection sensor disposed at a predetermined position upstream of an image forming position of the image forming unit on the conveyance path; When the image formation determination unit stops image formation because the recording medium is a type outside the product specifications, the image formation determination unit executes a purge process in which the recording medium being conveyed is discharged blank outside the apparatus, or a jam detection process in which the recording medium is stopped midway along the conveyance path, When image formation is to be performed even if the recording medium is of a type outside the product specifications, a conveying speed of the recording medium and / or a fixing control temperature are set as image formation conditions during image formation according to the determined conveying performance, and the image formation is performed under the set image formation conditions. Image forming device.

4. A paper feed conveying unit including a main body paper feed tray and a manual paper feed tray built into the main body, which feeds and conveys recording media from the main body paper feed tray or the manual paper feed tray to a conveying path; an image forming unit that forms an image on the recording medium conveyed through the conveyance path; a media sensor disposed on the conveying path upstream of the image forming unit in a conveying direction of the recording medium, the media sensor measuring one or more paper physical properties of the conveyed recording medium; a first determination unit that determines the type of the recording medium based on the paper physical properties measured by the media sensor; a second determination unit that determines the transport performance of the recording medium transported through the transport path; an image formation determination unit that determines whether or not to perform image formation based on the conveying performance determined by the second determination unit when the type of the recording medium determined by the first determination unit is outside of product specifications; Equipped with The type of the recording medium is outside the product specifications when the paper type of the recording medium determined by the first determination unit is coated paper or an envelope, and the recording medium is fed from the main body paper feed tray. Image forming device.

5. The image formation determination unit When the type of the recording medium determined by the first determination unit is outside the product specifications, if the conveying performance determined by the second determination unit satisfies a predetermined performance, image formation is performed on the recording medium of the type outside the product specifications without stopping image formation; 5. An image forming apparatus according to claim 1, wherein if the type of recording medium determined by the first determination unit is outside the product specifications, and if the conveying performance determined by the second determination unit does not satisfy a predetermined performance, image formation is stopped.

6. 5. The image forming apparatus according to claim 4, wherein the second determination unit determines whether the transport performance satisfies a predetermined performance based on the transport time tx from when the paper feed transport unit starts feeding the recording medium until the recording medium reaches the detection position of a paper detection sensor located at a predetermined position upstream of the image forming position of the image forming unit on the transport path.

7. The image forming apparatus of claim 4, wherein the second judgment unit judges whether the conveying performance satisfies a predetermined performance from the detection result of the driving torque of the drive motor of the paper feed conveying unit in any section from when the paper feed conveying unit starts feeding the recording medium to when the recording medium reaches the detection position of a paper detection sensor located at a predetermined position upstream of the image forming position of the image forming unit on the conveying path.

8. When the image formation determination unit stops image formation because the recording medium is a type outside the product specifications, the image formation determination unit executes a purge process in which the recording medium being conveyed is discharged blank outside the apparatus, or a jam detection process in which the recording medium is stopped midway along the conveyance path, An image forming apparatus as described in claim 6 or claim 7, wherein when image formation is performed even if the recording medium is a type outside the product specifications, the conveying speed and / or fixing control temperature of the recording medium are set as image formation conditions during image formation according to the determined conveying performance, and the image formation is performed under the set image formation conditions.

9. the image formation determination unit determines a document type to be formed on the recording medium from a color mode and / or graphic or text information included in the print data; 9. The image forming apparatus according to claim 2, wherein the image formation determining unit sets the image forming conditions in accordance with the determined document type in addition to the conveying performance.

10. When image formation is performed on the recording medium of a type outside the product specifications, information on the occurrence of a jam of the conveyed recording medium is stored in a storage unit as history data in association with the type of the recording medium determined by the first determination unit, When the storage unit has history data associated with the type of recording medium determined by the first determination unit, the image formation determination unit:

10. An image forming apparatus according to claim 1, wherein if the history of jam occurrence in the history data is less than a predetermined threshold, image formation is performed based on the conveying performance determined by the second judgment unit, and if the history of jam occurrence is equal to or greater than the predetermined threshold, image formation is stopped regardless of the judgment result of the second judgment unit.

11. When image formation is performed on the recording medium of a type outside the product specifications in one print job, the image formation determination unit stores the type of the recording medium determined by the first determination unit as history data in a storage unit in association with jam occurrence information of the conveyed recording medium and image formation conditions, and An image forming apparatus as described in claim 2, claim 8, or claim 9, wherein, when an image is formed on a recording medium of a type outside the product specifications, if no jam occurs on the transported recording medium, the image forming conditions used when the image was formed are stored in the history data, and the stored image forming conditions are applied when subsequent images are formed on the same type of recording medium for the same print job.

12. When image formation is performed on the recording medium of a type outside the product specifications in one print job, the image formation determination unit stores the type of the recording medium determined by the first determination unit as history data in a storage unit in association with jam occurrence information of the conveyed recording medium and image formation conditions, and When an image is formed on the recording medium of a type outside the product specifications, if no jam occurs on the conveyed recording medium, the image forming conditions at the time of the image formation are stored in the history data, and the stored image forming conditions are applied when an image is formed on the recording medium of the same type in the same print job thereafter, When an image is formed on a recording medium that is not of a type specified for the product, if a jam occurs on the conveyed recording medium, 10. An image forming apparatus according to claim 2, claim 8, or claim 9, wherein, if the cumulative number of jam occurrences in the print job is less than a predetermined threshold, image forming conditions different from the image forming conditions when the image formation was performed are stored in the history data, and the stored image forming conditions are applied when forming images on the same type of recording medium in the same print job thereafter, and if the number of jam occurrences is equal to or greater than the predetermined threshold, the print job is canceled.

13. further comprising an operation display unit that receives setting inputs from a user and displays various information; When the type of the recording medium determined by the first determination unit is outside the product specifications, 13. The image forming apparatus according to claim 1, wherein the operation display unit displays a message indicating that the recording medium is outside the product specifications, and / or the image forming apparatus accepts permission from the user to perform printing using the recording medium outside the product specifications.

14. A program for controlling an image forming apparatus including: a conveying path; an image forming unit that forms an image on a recording medium conveyed on the conveying path; and a media sensor that is disposed on the conveying path upstream of the image forming unit in a conveying direction of the recording medium and that measures one or more paper physical properties of the conveyed recording medium, a step (a) of determining the type of the recording medium based on the paper physical properties measured by the media sensor; determining the conveyance performance of the recording medium conveyed through the conveyance path by a paper feed conveyance unit; (b) and a step (c) of determining whether or not to perform image formation based on the conveying performance determined in the step (b) when the type of the recording medium determined in the step (a) is outside the product specifications; A process comprising: The type outside the product specifications is a type in which the basis weight category determined in step (a) is equal to or greater than a predetermined basis weight, In the step (b), it is determined whether or not the conveying performance satisfies a predetermined performance from a detection result of a drive torque of a drive motor of the paper feed conveying unit in any section from when the paper feed conveying unit starts feeding the recording medium to a detection position of a paper detection sensor arranged at a predetermined position upstream of an image forming position of the image forming unit in the conveying path. A control program that causes a computer to execute a process.

15. A program for controlling an image forming apparatus including: a conveying path; an image forming unit that forms an image on a recording medium conveyed on the conveying path; and a media sensor that is disposed on the conveying path upstream of the image forming unit in a conveying direction of the recording medium and that measures one or more paper physical properties of the conveyed recording medium, a step (a) of determining the type of the recording medium based on the paper physical properties measured by the media sensor; determining the conveyance performance of the recording medium conveyed through the conveyance path by a paper feed conveyance unit; (b) and a step (c) of determining whether or not to perform image formation based on the conveying performance determined in the step (b) when the type of the recording medium determined in the step (a) is outside the product specifications; A process comprising: The type outside the product specifications is a type in which the basis weight category determined in step (a) is equal to or greater than a predetermined basis weight, In step (b), it is determined whether or not the conveying performance satisfies a predetermined performance in accordance with a conveying time tx from when the paper feed conveying unit starts feeding the recording medium until when the recording medium reaches a detection position of a paper detection sensor disposed at a predetermined position upstream of an image forming position of the image forming unit in the conveying path, In the step (c), if the image formation is to be stopped because the recording medium is of a type outside the product specifications, a purge process is performed in which the recording medium being conveyed is discharged blank outside the apparatus, or a jam detection process is performed in which the recording medium is stopped midway along the conveyance path, When image formation is to be performed even if the recording medium is of a type outside the product specifications, a conveying speed of the recording medium and / or a fixing control temperature are set as image formation conditions during image formation according to the determined conveying performance, and the image formation is performed under the set image formation conditions. A control program that causes a computer to execute a process.

16. A program for controlling an image forming device comprising: a main body paper feed tray built into the main body; a manual feed tray; a transport path; an image forming unit that forms an image on a recording medium transported from the paper feed tray or the manual feed tray in the transport path; and a media sensor that is arranged upstream of the image forming unit in the transport path in the transport direction of the recording medium and that measures one or more paper physical properties related to the transported recording medium, a step (a) of determining the type of the recording medium based on the paper physical properties measured by the media sensor; determining the conveyance performance of the recording medium conveyed through the conveyance path by a paper feed conveyance unit; (b) and a step (c) of determining whether or not to perform image formation based on the conveying performance determined in the step (b) when the type of the recording medium determined in the step (a) is outside the product specifications; A process comprising: The type of the recording medium is outside the product specifications when the paper type of the recording medium determined in step (a) is coated paper or an envelope, and the recording medium is fed from the main body paper feed tray. A control program that causes a computer to execute a process.

17. In the step (c), When the type of the recording medium determined in step (a) is outside the product specifications, if the conveying performance determined in step (b) satisfies a predetermined performance, image formation is performed on the recording medium of the type outside the product specifications without stopping image formation; 17. A control program according to claim 14, wherein if the type of recording medium determined in step (a) is outside the product specifications, and if the conveying performance determined in step (b) does not satisfy a predetermined performance, image formation is stopped.

Images